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Materials in Electronics/Confined Particles/1D Finite Wells

We have seen the result of an infinite potential well, but this is not a situation that can exist in real life - a point cannot have infinite potential with respect to another. Let us consider the symmetric finite potential well, right. It is easier mathematically if the well is centred around the origin. As before, the potential in the well (between -L and L) is 0, but outside the well, it is a finite value, V (equal on both sides):

 * $$V\left( x \right) = \begin{cases}

V,\quad x < -L \\ 0, \quad -L \le x \le L \\ V, \quad x > L                            \end{cases} $$

Because the potential outside is finite, an electron could escape from the well even if its potential was less than V (quantum tunnelling), so we expect to see a wavefunction which does not go to zero at the boundaries of the well.

Let's break up our wavefunction into three pieces, one on each side and one inside the well:

 * $$\psi\left( x \right) = \begin{cases}

\psi_1\left( x \right), & \quad x<-L \\ \psi_2\left( x \right), & \quad -L \le x \le L \\ \psi_3\left( x \right), & \quad x>L \end{cases}$$

We will solve each of the wavefunctions separately using Schrödinger's Equation:

 * $$-\frac{\hbar^2}{2 m} \frac{d^2}{d x^2}\psi\left( x \right) + V(x) \psi = E \psi$$

Inside the Well
Inside the well, the potential is zero, so we can rewrite Schrödinger's Equation as follows:

 * $$-\frac{\hbar^2}{2 m} \frac{d^2}{d x^2} \psi_2\left( x \right) = E \psi_2 $$

Rearranging,

 * $${{d^2} \over {dx^2 }}\psi_2 \left( x \right) = - {{2mE} \over \hbar^2 }\psi_2 \left( x \right)$$

Recall that the energy is given by

 * $$E\,$$
 * $$ = T\left( x \right) + V\left( x \right)\,$$
 * $$ = {{\hbar ^2 k^2 } \over {2m}}$$
 * }
 * $$ = {{\hbar ^2 k^2 } \over {2m}}$$
 * }

Substituting for E in our differential equation gives:

 * $${{d^2 \psi_2 \left( x \right)} \over {dx^2 }} = - k^2 \psi_2 \left( x \right)$$

This is now a second-order differential equation with a standard form. The general solution is given by:

 * $$\psi_2 \left( x \right) = A \sin{kx} + B \cos{kx}$$

The energies here are

 * $$E = \frac{k^2 \hbar^2}{2m} $$

In this general solution, A and B can be any complex numbers, and k can be any real number.

Outside the Well
We will now look at the region with the wavefunction ψ1, i.e. to the left. The region to the right of the well will have an identical derivation. For the region outside of the box to the left, since the potential is constant, V(x) = V our statement of Schrödinger's Equation becomes:

 * $$-\frac{\hbar^2}{2 m} \frac{d^2}{d x^2}\psi_1\left( x \right) = (E - V) \psi_1 $$

There are two possible families of solutions, depending on whether E is less than V (the particle is bound in the potential well) or E is greater than V (the particle is free).

Unbound State
For a free particle, E > V, and letting
 * $$\kappa^2=\frac{2m(E - V)}{\hbar^2}$$

produces
 * $$\frac{d^2}{d x^2} \psi_1 \left(x \right) = -\kappa^2 \psi_1 $$

with the same solution form as inside the well:

 * $$\psi_1 = C \sin(\kappa x) + D \cos(\kappa x)\quad$$

Bound State
This analysis will first focus on the bound state, where E-V. Letting
 * $$\alpha^2 = \frac{2m(V - E)}{\hbar^2}$$

produces
 * $$\frac{d^2}{d x^2} \psi_1\left(x \right) = \alpha^2 \psi_1\left(x \right) $$

where the general solution is exponential:
 * $$\psi_1\left(x \right) = Fe^{- \alpha x}+ Ge^{ \alpha x} \,\!$$

Similarly, for the other region outside the box:

 * $$\psi_3\left(x \right) = He^{- \alpha x}+ Ie^{ \alpha x} \,\!$$

Now in order to find the specific solution for the problem at hand, we must specify the appropriate boundary conditions and find the values for A, B , F , G , H and I that satisfy those conditions.

Finding Wavefunctions for the Bound State
Solutions to the Schrödinger Equation must be continuous, and continuously differentiable. These requirements are boundary conditions on the differential equations previously derived.

In this case, the finite potential well is symmetrical, so symmetry can be exploited to reduce the necessary calculations, by choosing wavefunctions of well defined parity.

Summarizing the previous sections:

 * $$\psi\left( x \right) = \begin{cases}

\psi_1\left( x \right), & \quad x<-L \\ \psi_2\left( x \right), & \quad -L \le x \le L \\ \psi_3\left( x \right), & \quad x>L \end{cases}$$

where we found the wavefunctions for the bound state, $$\psi_1, \psi_2 \,\!$$ and $$\psi_3 \,\!$$ to be:
 * $$\psi_1 \left( x \right) = Fe^{- \alpha x} + Ge^{ \alpha x} \,\!$$
 * $$\psi_2 \left( x \right) = A \sin(kx)     + B \cos(kx)\quad$$
 * $$\psi_3 \left( x \right) = He^{- \alpha x} + Ie^{ \alpha x} \,\!$$

Where

 * $$k=\frac{\sqrt{2mE}}{\hbar}$$
 * $$\alpha=\frac{\sqrt{2m(V - E)}}{\hbar}$$

We see that as x goes to $$-\infty$$, the F term goes to infinity. Likewise, as x goes to $$+\infty$$, the I term goes to infinity. As the wave function must be finite for all x, this means we must set F = I = 0, and we have:

 * $$\psi_1 \left( x \right) = G e^{ \alpha x} \,\!$$
 * $$\psi_2 \left( x \right) = A \sin(kx)     + B \cos(kx)$$
 * $$\psi_3 \left( x \right) = H e^{- \alpha x} \,\!$$

Next, we know that the overall $$\psi \,\!$$ function must be continuous and differentiable. In other words the values of the functions and their derivatives must match up at the dividing points:

 * {| cellpadding=4

 * $$\psi_1(-L) = \psi_2(-L) \,\!$$
 * width=75|
 * $$\psi_2(L) = \psi_3(L) \,\!$$
 * $$\frac{d\psi_1}{dx}(-L) = \frac{d\psi_2}{dx}(-L) \,\!$$
 * $$\frac{d\psi_2}{dx}(L) = \frac{d\psi_3}{dx}(L) \,\!$$
 * }
 * $$\frac{d\psi_2}{dx}(L) = \frac{d\psi_3}{dx}(L) \,\!$$
 * }

Firstly, we need to recall that there must exist wavefunction solutions with well defined parity, odd or even. Since the sine function is odd and the cosine function is even, we can search for a wavefunction solution in the well of the form of sine or cosine. We can now analyse the even and odd wavefunctions separately. It will be shown that for bound states, the even an odd solutions always have different energies. This means there is no degeneracy, and thus there are no bound eigen-states which are a linear combination of sine and cosine, and all bound states have well defined parity. Below is a diagram showing an even parity wavefunction against an odd parity wavefunction. These are illustrative only and do not necessarily relate to the given problem, they are meant to confer the symmetry of the wavefunctions only.

Even Wavefunctions
The wavefunction for the even solution has no odd (sine) components, so the three wavefunctions are now:

 * $$\psi_1 \left( x \right) = G e^{ \alpha x} \,\!$$
 * $$\psi_2 \left( x \right) = B \cos(kx)$$
 * $$\psi_3 \left( x \right) = H e^{- \alpha x} \,\!$$

Let us now consider the conditions requiring continuity of the wavefunction at the two "joining points":

 * $$G e^{-\alpha L}=B \cos(-kL)\,$$
 * $$H e^{-\alpha L}=B \cos( kL)\,$$

Since the cosine function is even, the two equations have the same right hand side. So we have

 * $$G e^{-\alpha L}=H e^{-\alpha L}\,$$
 * $$G = H \,$$

The conditions of continuity of the derivatives at the boundaries give us the following:

 * $$\alpha G e^{-\alpha L}=-kB \sin(-kL)\,$$
 * $$\alpha H e^{-\alpha L}= kB \sin(kL)\,$$

Given the equality of G and H, we can now divide any equation from the second conditions by any from the first conditions. I will choose the first equations from each set:

 * $$\frac{\alpha G e^{-\alpha L}}{G e^{-\alpha L}}=\frac{-kB \sin(-kL)}{B \cos(-kL)}$$

We now have an expression for α (recall that the tan function is odd, so the negatives cancel):

 * $$\alpha = k \tan \left( kL \right),$$

where

 * $$k=\frac{\sqrt{2mE}}{\hbar}$$
 * $$\alpha=\frac{\sqrt{2m(V - E)}}{\hbar}$$

This can be reduced to the following equations:

 * $$\frac{\alpha}{k} = \tan \left( kL \right),$$
 * $$\sqrt{\frac{V-E}{E}}=\tan \left( \frac{\sqrt{2mE}}{\hbar}L \right)$$

An even parity wavefunction exists at the energies (E) that satisfy this equation. This equation is extremely difficult to solve analytically, but can readiliy be solved numerically or graphically. This will be done later. First, we will derive the odd parity wavefunctions.

Odd Wavefunctions
The wavefunction for the odd solution has no even (cosine) components, so the three wavefunctions are now:

 * $$\psi_1 \left( x \right) = G e^{ \alpha x} \,\!$$
 * $$\psi_2 \left( x \right) = A \sin(kx)$$
 * $$\psi_3 \left( x \right) = H e^{- \alpha x} \,\!$$

Let us now consider the conditions requiring continuity of the wavefunction at the two "joining points":

 * $$G e^{-\alpha L}=A \sin(-kL) \,$$
 * $$-H e^{-\alpha L}=A \sin( kL) \,$$

Since sine is an odd function, we can see that

 * $$G e^{-\alpha L}=-H e^{-\alpha L} \,$$
 * $$G=-H \,$$

The conditions of continuity of the derivatives at the boundaries give us the following:

 * $$\alpha G e^{-\alpha L}=kA \cos(-kL) \,$$
 * $$\alpha H e^{-\alpha L}=kA \cos(kL) \,$$

Dividing the first equation from the second by the first equation from the first set (any combination would do), we get:

 * $$\frac{\alpha G e^{-\alpha L}}{G e^{-\alpha L}}=\frac{kA \cos(-kL)}{A \sin(-kL)}$$
 * $$\alpha=k \cot \left( -kL \right) \,$$

And because cot is an odd function,

 * $$\frac{\alpha}{k}=-\cot \left(kL \right)$$
 * $$\sqrt{\frac{V-E}{E}}=-\cot \left( \frac{\sqrt{2mE}}{\hbar}L \right)$$

An odd parity wavefunction exists whenever the energy satisfies this condition. As with the even wavefunction, this is not a trival equation to solve analytically, but can be solved graphically or numerically.

Graphical Solution for Energy Levels
Let us quickly restate our objectives here. We wish to find the energies of the bound states of an electron in a finite square well. An energy level exists only when one of the following conditions is satisfied:

 * $$\frac{\alpha}{k}=\tan \left(kL \right)$$

 * $$\frac{\alpha}{k}=-\cot \left(kL \right)$$

We can plot the three functions together on a graph against energy, E. The conditions are satisfied at the crossing points as shown below. We therefore can find the allowed energy levels by reading the energy at the crossings. Before we can plot a graph, we need to choose some properties of our system. Let us set the width of the well to be 0.4nm in total (L=0.2nm) and set the potential barrier,V, to 75eV.

We see that there are six permitted energy states: even wavefunctions at about 2, 17 and 46eV and odd wavefunctions at about 7.5, 30 and 64.5eV. This method provides an easy way to find out how many levels there are and approximately where they are located. While the graphical method is theoretically as accurate as any, it is possible to practically obtain much higher accuracy using purely numerical methods.

Also notice that however small the potential barrier, there will always be at least one even solution, corresponding to the first intersection. The existence of an odd solution depends on the value of V.

Numerical Methods for Energy Levels
There are many numerical methods that could be used to solve these equations. While the equations cannot be solved exactly, they can be differentiated. This means that we can use Newton-Raphson Iterations, which are typically fast to converge. By using our graphical method to give us a rough idea of the locations of the roots, we can select suitable starting values for the iterations.

The two equations below are the equations to solve using the iteration (the Newton-Raphson method requires a function equal to zero).

 * $$\frac{\alpha}{k} - \tan \left(kL \right)=0$$
 * $$\frac{\alpha}{k} + \cot \left(kL \right)=0$$

The derivates of these equations are needed for the iteration (unless done automatically by a computer), and these are given below:

\frac{ -V } {2E^2 \sqrt{\frac{V-E}{E}}}   - \frac{Lm} {\hbar \sqrt{2m E}} \sec^2 \left( \frac{L \sqrt{2mE}}{\hbar} \right) $$

\frac{ -V } {2E^2 \sqrt{\frac{V-E}{E}}}  - \frac{Lm} {\hbar \sqrt{2m E}} \csc^2 \left( \frac{L \sqrt{2mE}}{\hbar} \right) $$

The table below shows the six levels in this system, the starting value for the iteration, and the energy to 5 decimal places.

Let's compare these to the first six energy levels for an infinite squre well, which we saw how to derive before:

As you can see, the energy levels are lower in the finite well than in the infinite well. This is due to the wavefunction extending beyond the well's boundaries, effectively resulting in a larger box. As a larger box results in lower energy levels, this makes sense.

Finding the Numerical Wavefunctions
We have found a way to evaluate the energy levels present in a finite potential well, which is usually the only information required, but we can also find the shape of the wavefunction. We already know the approximate shape - it is sinusoidal inside the well and decays exponentially to zero outside it.

First Energy Level
Let's start at the first (lowest) energy level, which is even. We already defined the wavefunction piecewise as follows:

 * $$\psi_1 \left( x \right) = G e^{ \alpha x} \,\!$$
 * $$\psi_2 \left( x \right) = B \cos(kx)$$
 * $$\psi_3 \left( x \right) = H e^{- \alpha x} \,\!$$

Now that we know the energy of the level, we can easily compute k and α. This means that we just have to find G, B and H. We have already shown that G=H. Because we will have to normalise the wavefunction later anyway, we can manipulate the scaling of the functions at this point without consequence. Let us set the value of B to 1. This way we just have to find the value of G (=H) which satisfies the continuity bondary condition:

 * $$\psi_3(L) = \psi_2(L) \,\!$$
 * $$G e^{-\alpha L}= \cos(kL)\,$$

Rearranging,

 * $$G=\frac{\cos(kL)}{e^{-\alpha L}}$$

The values of k and α and E at the first energy level

 * E = 1.89660eV = 3.03868 × 10-19 J
 * k = 7.05548 × 109
 * α= 4.38034 × 1010

This gives

 * G = 1014.31

We can now plot the wavefunction against position. Note that we have not performed normalisation yet, so the units are arbitrary.

We can see that the wavefunction extends visibly into the classically forbidden zone (blue). If the exact matching of the gradient is hard to fathom, remeber that it was this very condition that led to the definitions for k and α. However, as the calculations leading to this point apply only to valid energies, if you try to plot the wavefunctions for a non-valid energy, you will get a continuous (as the method of obtaining G enforces this) but not smooth graph, implying that the solution does not fit the physical system.

Because we have no simple relationship between the energy and shape of the graph (notice that G changes as a reasonably complex function of E), we can't find an easily expressible normalisation coefficient. However, by integrating the square of the wavefunction, we can still evaluate it:

 * $$\int_{-\infty}^{\infty} | \psi(x) |^2 dx =1$$
 * $$\int_{-\infty}^{-L} | \psi_1(x) |^2 dx+

\int_{-L}^{L} | \psi_2(x) |^2 dx+ \int_{L}^{\infty} | \psi_3(x) |^2 dx=1$$
 * $$\psi_0^2 \left[\int_{-\infty}^{-L} G^2 e^{2\alpha x} dx+

\int_{-L}^{L} \cos^2(kx) dx+ \int_{L}^{\infty} G^2 e^{-2\alpha x} dx \right]=1$$

This integral is quite simple, and yields the following normalisation coefficient:

 * ψ0=66990.6

Compare this with 70710.7 for an infinite well. Remember to account for the units (often nanometres cause problems) when doing this integral. It makes sense that the normalisation coeffiecient is lower here, as the wavefunction extends further, so has a higher area when the sinusoid is scaled to 1, meaning that it must be multiplied by a smaller number to give a unity probability of finding the particle somewhere.

Second Energy Level
Now let's consider the second energy level, which is odd. The wavefunction is given by:

 * $$\psi_1 \left( x \right) = G e^{ \alpha x} \,\!$$
 * $$\psi_2 \left( x \right) = A \sin(kx)$$
 * $$\psi_3 \left( x \right) = H e^{- \alpha x} \,\!$$

where G = -H. Setting A=1, and proceeding as above, we get the following:

 * E = 7.56592eV = 1.21219389 × 10-18 J
 * k = 1.40919 × 1010
 * α= 7.99293 × 109

This gives a G of 1432.53 and leads to the graph below:

To get the normalisation coeffiecient, we put

 * $$\int_{-\infty}^{\infty} | \psi(x) |^2 dx =1$$
 * $$\int_{-\infty}^{-L} | \psi_1(x) |^2 dx+

\int_{-L}^{L} | \psi_2(x) |^2 dx+ \int_{L}^{\infty} | \psi_3(x) |^2 dx=1$$
 * $$\psi_0^2 \left[\int_{-\infty}^{-L} G^2 e^{2\alpha x} dx+

\int_{-L}^{L} \sin^2(kx) dx+ \int_{L}^{\infty} G^2 e^{-2\alpha x} dx \right]=1$$

which gives a normalisation coefficent of 66849.7. This is marginally smaller than the coefficient for the first energy level. Since the wavefunction extends further into the potential barrier region (this is not clearly apparent in the graph, but it is just observable), this is to be expected. We can see this pattern continue through all six levels:

Unbound States
There are also permitted energy levels for a particle above the energy of the top of the well, V. These are called unbound states as they do not decay to zero outside the well. However, they are certainly still affected by it. Unbound states are also called continuum states, because unlike the discrete bound states they have a solution for the continuous range of energies which fulfill
 * $$E > V \,$$

Recall the definition for α:

 * $$\alpha=\frac{\sqrt{2m(V - E)}}{\hbar}$$

In unbound states, this is imaginary, which means that we cannot use the same method as we could for bound states. If you look at the graphical solution, you can see that the line for α/k ends at V, meaning that there are no more valid bound state energy levels past this point.

We saw near the beginning of this page that the wavefunction for an unbound state outside the well is

 * $$\psi_1 \left( x \right) = C \sin(\kappa x) + D \cos(\kappa x)\quad$$

where

 * $$\kappa=\sqrt{\frac{2m(E - V))}{\hbar^2}}$$

The solution inside the well is the same as for the bound states:

 * $$\psi_2 \left( x \right) = A \sin{kx} + B \cos{kx}$$

Becaue the potential is symmetric around the origin, there must be solutions of defined parity also for unbound states, so we will choose a basis of odd and even wavefunctions. As before, we know that the overall wavefunction must be continuous and differentiable. In other words the values of the functions and their derivatives must match up at the dividing points:

 * {| cellpadding=4

 * $$\psi_1(-L) = \psi_2(-L) \,\!$$
 * width=75|
 * $$\psi_1(L) = \psi_2(L) \,\!$$
 * $$\frac{d\psi_1}{dx}(-L) = \frac{d\psi_2}{dx}(-L) \,\!$$
 * $$\frac{d\psi_1}{dx}(L) = \frac{d\psi_2}{dx}(L) \,\!$$
 * }
 * $$\frac{d\psi_1}{dx}(L) = \frac{d\psi_2}{dx}(L) \,\!$$
 * }

Odd Wavefunctions
For odd wavefunctions, we can ignore the cosine terms for $$\psi_2$$, but not for $$\psi_1$$ and $$\psi_3$$:

 * $$\psi_2 \left( x \right) = A \sin{kx} \,\!$$
 * $$\psi_1 \left( x \right) = C \sin{\kappa x} + D \cos{\kappa x}=C \sin{(\kappa x-\phi)}$$
 * $$\psi_3 \left( x \right) = E \sin{\kappa x} + F \cos{\kappa x}=C \sin{(\kappa x+\phi)}$$

$$\psi_1$$ and $$\psi_3$$ are not odd functions on their own, but the general function $$\psi$$ defined for all x is odd, noting that for any $$x_0 > L$$:

 * $$\psi_1 \left( -x_{0} \right) = \psi_3 \left( x_{0} \right)$$

Applying the boundary condition of continuity of the wavefunction, we get the same result at each boundary:

 * $$C \sin{(\kappa L + \phi)}= A \sin{kL}\,\!$$

taking the derivative and requiring continuity at L, we get:

 * $$\kappa C \cos{(\kappa L + \phi)}= k A \cos{kL}\,\!$$

The choice of wavefunctions of a defined parity reduces the problem to tailoring the values of the wavefunction and its derivative only at one point (as the other yields identical equations). Thus we have two equations with three variables. We will choose C, the amplitude of the wavefunction outside the well to be unity. At the end we will normalize $$\psi$$ to unity over the full 1D finite well.

Dividing the equation derived from continuity of the wavefunction by that of the continuity of the derivative:

 * $$\tan{(\kappa L + \phi)}=\frac{\kappa}{k} \tan {kL}$$

 * $$\phi=\arctan{(\frac{\kappa}{k} \tan {kL}}) - \kappa L$$

Inserting the phase $$\phi$$ into the equation of continuity at L, and taking C=1, we get:
 * $$A=\frac {\sin{(\kappa L + \phi)}} {\sin{kL}} $$

Thus we see that there is an odd wavefunction solution for any energy, well depth, and width. There is a resonance above the well when:

 * $$\sin{kL}=0,\!$$

This is similar to the Fabri Perot resonances in optics.

Even Wavefunctions
In the same manner as for the odd wavefunctions, we can ignore the sine terms for $$\psi_2$$, but not for $$\psi_1$$ and $$\psi_3$$ for the even wavefunctions:

 * $$\psi_2 \left( x \right) = B \cos{kx} \,\!$$
 * $$\psi_1 \left( x \right) = C \sin{\kappa x} + D \cos{\kappa x}=D \cos{(\kappa x-\phi)}$$
 * $$\psi_3 \left( x \right) = E \sin{\kappa x} + F \cos{\kappa x}=C \cos{(\kappa x+\phi)}$$

Applying the boundary condition of continuity of the wavefunction, we get the same result at each boundary:

 * $$C \cos{(\kappa L + \phi)}= B \cos{kL}\,\!$$

taking the derivative and requiring continuity at L, we get:

 * $$\kappa C \sin{(\kappa L + \phi)}= k A \sin{kL}\,\!$$

Dividing the equation derived from continuity of the wavefunction by that of the continuity of the derivative:

 * $$\tan{(\kappa L + \phi)}=\frac {k} {\kappa} \tan {kL}$$

 * $$\phi=\arctan{(\frac {k} {\kappa} \tan {kL}}) - \kappa L$$

Inserting the phase $$\phi$$ into the equation of continuity at L, and taking C=1, we get:

 * $$A=\frac {\cos{(\kappa L + \phi)}} {\cos{kL}} $$

Thus we see that there is an even wavefunction solution for any energy, well depth, and width. There is a resonance above the well when:

 * $$ \cos{kL}=0 ,\!$$


text:
Talk:Music Theory/Dance

I added some less ridiculously-broad information and clarified a couple of mischaracterizations, but this page still needs a lot of work. It should also be accurately entitled "Electronic Music", since "Dance Music" might be said to include any form of music specifically geared toward dancing, from the waltz to tribal drumming to salsa. --SamClayton 05:05, 19 September 2007 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Music Theory/Dance


text:
Scratch/Planning

*Note* - This is a "meta page", and a central location to discuss the planning and organization of this Wikibook. Feel free to add your thoughts, ideas, humorous incidents, and rambling prose about Scratch in this area. The focus should be the Scratch programming language, but slightly off topic comments loosely related will also be tolerated.

The "talk" pages attached to the other modules of this Wikibook should be used to help organize or raise objections to those specific pages, while this is more about the project as a whole.

If you add a comment, please sign your comments with four tildes like this:  --~

Welcome to the Scratch Wikibook
If you are reading this, you have done a pretty good job of navigating through this Wikibook. The tone I'm trying to set for this Wikibook is one of being rather relaxed, and to try out some very new ideas for textbook development, but also allow traditional "textbook-like" content to be created. Please help me in discussing your thoughts and criticisms about this Wikibook, and keep the goal in mind that we are here to help people learn about Scratch. --Rob Horning 15:17, 27 May 2007 (UTC) The Wikibook is going through a major period of changes as it is updated to Scratch 1.4 By me Tanderson11, I am updating images and adding terminology as my current project now. --Tanderson11 (talk) 23:20, 31 December 2009 (UTC)

I applaud the start of a tutorial on Scratch, but I don't know if I have time to develop any materials for it. If you see anything in my Tech News (http://www.soe.ucsc.edu/~karplus/tech_club/) that could be useful, let me know. I'd have no problem including any of that in the wikibook. Kevin k (talk) 17:35, 27 December 2007 (UTC)

Layout of the Book
It looks like this book hasn't seen a lot of edits lately and is only around 10% complete as of 2015. I am interested in working on it and I wanted to know if some of the original authors have any particular structure in mind. Like am outline or something. There are some redlinks already that I assume are planned pages? Thanks, Blackhat999 (discuss • contribs) 21:24, 11 November 2015 (UTC)

Updating to Scratch 3.0
Most of the information here is pretty dated; There have been two major releases of Scratch with an entirely different web interface, system requirements, and other changes. Would it be a good idea to update the info here? And how would I go into add such info? Sorry, I don't have as much experience into Wikibooks. Thanks.

And also, please reply to this message with reply to. SergioFLS (discuss • contribs) 13:39, 10 October 2023 (UTC)
 * Welcome to Wikibooks! As far as I can see, this book is the perfect book to make updates. As for how to go about with it, you can do whatever is reasonable. For example, maybe you can expand the Scratch/Initial Setup/What is Scratch? page since it seems to be an undeveloped draft (since 2015). Further information regarding editing Wikibooks can be found in Using Wikibooks, but I'd recommend to be bold. If you have any questions, the reading room will be a good place to guide you to the right forum. —Atcovi (Talk - Contribs) 13:54, 10 October 2023 (UTC)
 * Thanks for your reply! While I haven't updated that page yet, I have updated some other pages to replace dead links and update info to Scratch 3.0. I will check out the other resources you've provided. SergioFLS (discuss • contribs) 16:43, 10 October 2023 (UTC)

title: Scratch/Planning


text:
Scratch/Learning Scratch

Learning Scratch

Getting Started

 * Introducing Scratch
 * Exploring
 * Sprites
 * Blocks

Tutorials

 * /Making Sprites/
 * /Stage Design/
 * /Custom Image Design/
 * Event Triggers and Blocks
 * /Basic Animation/
 * /Movement/
 * Scene and Stage Changes

title: Scratch/Learning Scratch


text:
Talk:FHSST Physics/Atomic Nucleus/Nuclear Reactors

Is there a reason this page spends a huge amount of time talking about a reactor design that is not in operation? --24.147.86.187 17:50, 27 May 2007 (UTC)


text:
Logic for Computer Scientists/Predicate Logic/Equivalence and Normal Forms

Equivalence and Normal Forms
Equivalence of formulae is defined as in the propositional case:

Definition 6
The formulae $$F$$ and $$G$$ are called (semantically) equivalent, if for all interpretations $$\mathcal{I}$$ for $$F$$ and $$G$$, $$\mathcal{I}(F)= \mathcal{I}(G)$$. We write $$F \equiv G$$.

The equivalences from the propositional case in theorem 4 equivalences hold and in addition we have the following cases for quantifiers.

Theorem 1
The following equivalences hold:

$$ \lnot \forall x F$$ $$ \equiv$$  $$ \exists x  \lnot F$$

$$ \lnot \exists x F$$ $$ \equiv$$ $$ \forall x \lnot F$$

If $$x$$ does not occur free in $$G$$:

$$ \forall x F \land G$$ $$ \equiv$$  $$ \forall x ( F \land G)$$

$$ \forall x F \lor G$$  $$\equiv$$  $$ \forall x ( F \lor G)$$

$$ \exists x F \land G$$ $$\equiv$$  $$ \exists x ( F \land G)$$

$$ \exists x F \lor G$$ $$\equiv$$  $$ \exists x ( F \lor G)$$

$$\forall x F \land \forall x G$$ $$ \equiv$$ $$ \forall x (F  \land G)$$

$$\exists x F \lor \exists x G$$ $$ \equiv$$  $$\exists x  (F \lor G)$$

$$\forall x \forall y \; F$$ $$\equiv$$ $$ \forall y \forall x F$$

$$\exists x \exists y \; F$$ $$ \equiv$$ $$\exists y \exists x F$$

Proof: We will prove only the equivalence $$ \forall x F \land G \equiv \forall x ( F \land G) $$ with $$x$$ has no free occurrence in $$G$$, as an example. Assume an interpretation $$\mathcal{I}= (U,\mathcal{A})$$ such that

 * $$ \mathcal{I}( \forall x F \land G) = true $$
 * $$\text{iff } \mathcal{I}(\forall x F)= true \text{ and } \mathcal{I}(G) = true $$

 * $$\text{iff } \text{ for all }  d \in U : \mathcal{I}_{[x/d]}(F) = true   \text{ and }

\mathcal{I}(G) = true $$

 * $$\text{iff } \text{ for all } d \in U : \mathcal{I}_{[x/d]}(F) = true   \text{ and }

\mathcal{I}_{[x/d]}(G) = true \text{ (x = does not occur free in = G)} $$

 * $$\text{iff } \text{ for all }  d \in U : \mathcal{I}_{[x/d]}((F \land G))= true $$

 * $$\text{iff } \mathcal{I}( \forall x ( F \land G)) = true.

$$ Note that the following symmetric cases do not hold:

$$\forall x F \lor \forall x G$$   is not equivalent to   $$\forall x  (F \lor G)$$

$$\exists x F \land \exists x G$$  is not equivalent to   $$\exists x  (F \land G)$$

The theorem for substituitivity holds as in the propositional case.

Example: Let us transform the following formulae by means of substituitivity and the equivalences from theorem 1:

(\lnot ( \exists x P(x,y) \lor \forall z Q(z)) \land \exists w  P(f(a,w)))$$

\equiv ((\lnot \exists x P(x,y) \land \lnot \forall z Q(z)) \land \exists w  P(f(a,w))) $$

\equiv ((\forall x \lnot P(x,y) \land \exists z \lnot Q(z)) \land \exists w  P(f(a,w))) $$

\equiv ( \exists w P(f(a,w)) \land (\forall x \lnot  P(x,y) \land \exists z \lnot Q(z))) $$

\equiv \exists w ( P(f(a,w)) \land \forall x (\lnot  P(x,y) \land \exists z \lnot Q(z))) $$

\equiv \exists w ( \forall x ( \exists z \lnot Q(z) \land \lnot  P(x,y)) \land  P(f(a,w))) $$

\equiv \exists w ( \forall x   \exists z (\lnot Q(z) \land \lnot  P(x,y)) \land  P(f(a,w))) $$

\equiv \exists w  \forall x   \exists z ((\lnot Q(z) \land \lnot  P(x,y)) \land  P(f(a,w))) $$

Definition 7
Let $$F$$ be a formula, $$x$$ a variable and $$t$$ a term. $$F[x/t]$$ is obtained from $$F$$ by substituting every free occurrence of $$x$$ by $$t$$. Note, that this notion can be iterated: $$F[x/t_1][y/t_2]$$ and that $$t_1$$ may contain free occurrences of $$y$$.

Lemma 1
Let $$F$$ be a formula, $$x$$ a variable and $$t$$ a term. $$\mathcal{I}(F[x/t]) = \mathcal{I}_{[x/\mathcal{I}(t)]}(F)$$

Lemma 2 (Bounded Renaming)
Let $$F= Q x G$$ be a formula, where $$Q \in \{\forall, \exists\}$$ and $$y$$ a variable without an occurrence in $$G$$, then $$F \equiv Q y G[x/y]$$

Definition 8
A formula is called proper if there is no variable which occurs bound and free and after every quantifier there is a distinct variable.

Lemma 3 (Proper Formula)
For every formula $$F$$ there is a formula $$G$$ which is proper and equivalent to $$F$$. Proof: Follows immediately by bounded renaming. Example: $$ F = \forall x \exists y\; p(x, f(y)) \land \forall x (q(x, y) \lor r(x)) $$ has the equivalent and proper formula $$ G= \forall x \exists y\;( p(x, f(y))) \land \forall z(q(z, u) \lor r(z) $$

Definition 9
A formula is called in prenex form if it has the form $$ Q_1 \cdots Q_n F$$, where $$Q_i \in \{\forall, \exists\}$$ with no occurrences of a quantifier in $$F$$

Theorem 2
For every formula there is a proper formula in prenex form, which is equivalent. Example: $$\forall x \exists y\;( p(x, g(y, f(x))) \lor \lnot q(z)) \lor \lnot \forall x \;r(x,z)$$

$$\forall x \exists y\;( p(x, g(y, f(x)) \lor \lnot q(z)) \lor \exists x \; \lnot  r(x,z)$$

$$\forall x \exists y\;( p(x, g(y, f(x)) \lor \lnot q(z)) \lor \exists v \lnot  r(v,z)$$

$$\forall x \exists y \exists v\; ( p(x, g(y, f(x)) \lor \lnot q(z)) \lor \lnot   r(v,z)$$

Proof: Induction over the structure of the formula gives us the theorem for an atomic formula immediately.
 * $$F = \lnot F_0$$: There is a $$G_0 = Q_1 y_1 \cdots Q_n y_n G'$$ with  $$Q_i \in \{ \forall, \exists\} $$, which is equivalent to $$F_0$$. Hence we have  $$F \equiv  \overline{Q_1} y_1 \cdots \overline{Q_n} y_n \lnot G' $$

where $$\overline{Q_i} = \begin{cases} \;\;\,\exists & if Q_i = \forall \\ \;\;\, \forall & if Q_i = \exists \end{cases} $$ $$ G_1 =  Q_1 y_1 \cdots Q_k y_k G_1' $$ $$G_2 =  Q_1' z_1 \cdots Q_l' z_l G_2' $$ where $$\{y_1, \cdots, y_n\} \cap \{z_1, \cdots , z_l\} = \emptyset $$ and hence $$ F \equiv Q_1 y_1 \cdots Q_k y_k Q_1' z_1 \cdots Q_l' z_l ( G_1' \circ G_2') $$ In the following we call proper formulae in prenex form PP-formulae or PPF’s.
 * $$F = F_1 \circ F_2$$ with $$\circ \in \{\land, \lor\} $$. There exists $$G_1, G_2$$ which are proper and in prenex form and $$G_1 \equiv F_1$$  and $$G_2 \equiv F_2$$. With bounded renaming we can construct

Definition 10
Let $$F$$ be a PPF. While $$F$$ contains a $$\exists$$-Quantifier, do the following transformation: $$F$$ has the form $$ \forall y_1, \cdots \forall y_n \exists z\; G$$ where $$G$$ is a PPF and $$f$$ is a $$n$$-ary function symbol, which does not occur in $$G$$.

Let $$F$$ be $$ \forall y_1, \cdots \forall y_n\;  G[z/f(y_1, \cdots ,y_n)] $$

If there exists no more $$\exists$$-quantifier, $$F$$ is in Skolem form.

Theorem 3
Let $$F$$ be a PPF. $$F$$ is satisfiable iff the Skolem form of $$F$$ is satisfiable.

Proof: Let $$F = \forall y_1 \cdots \forall y_n \exists z\; G$$; after one transformation according to the while-loop we have $$ F' = \forall y_1 \cdots \forall y_n \; G [z/ f(y_1, \cdots, y_n) $$ where $$f$$ is a new function symbol. We have to prove that this transformation is satisfiability preserving: Assume $$F'$$ is satisfiable. than there exists a model $$\mathcal{I}$$ for $$F'$$ $$\mathcal{I} $$ is an interpretation for $$F$$. From the model property we have for all $$u_1, \cdots, u_n \in U_\mathcal{I}$$ $$ \mathcal{I}_{[y_1/u_1] \cdots [y_n/u_n]}(G[z/f(y_1, \cdots, y_n)]) = true $$ From Lemma 1 we conclude $$ \mathcal{I}_{[y_1/u_1] \cdots [y_n/u_n] [z/v]} (G) = true $$ where $$v = \mathcal{I}(f(u_1, \cdots, u_n)$$. Hence we have, that for all $$u_1, \cdots , u_n \in U_\mathcal{I}$$ there is  a $$ v \in U_\mathcal{I}$$, where  $$ \mathcal{I}_{[y_1/u_1] \cdots [y_n/u_n] [z/v]} (G) = true $$ and hence we have, that $$\mathcal{I}(\forall y_1 \cdots \forall y_n \exists z\; G) = true$$, which means, that $$\mathcal{I}$$ is a model for $$F$$.

For the opposite direction of the theorem, assume that $$F$$ has a model $$\mathcal{I}$$. Then we have, that for all $$u_1, \cdots, u_n \in U_\mathcal{I}$$, there is a $$ v \in U_\mathcal{I}$$, where $$ \mathcal{I}_{[y_1/u_1] \cdots [y_n/u_n] [z/v]} (G) = true $$ Let $$\mathcal{I'}$$ be an interpretation, which deviates from $$\mathcal{I}$$ only, by the fact that it is defined for the function symbol $$f$$, where $$\mathcal{I}$$ is not defined. We assume that $$f^{\mathcal{I}'}(u_1, \cdots, u_n) = v$$, where $$v$$ is chosen according to the above equation.

Hence we have that for all $$u_1, \cdots, u_n \in U_\mathcal{I}'$$ $$ \mathcal{I}'_{[y_1/u_1] \cdots [y_n/u_n][z/f^{\mathcal{I}'}(u_1, \cdots, u_n)]}(G) = true $$ and from Lemma 1 we conclude that for all $$u_1, \cdots, u_n \in U_\mathcal{I}$$ $$ \mathcal{I}'_{[y_1/u_1] \cdots [y_n/u_n]}(G[z/f^(y_1, \cdots, y_n)]) = true $$ which means, that $$\mathcal{I}'(\forall y_1 \cdots \forall y_n \; G[z/f(y_1, \cdots, y_n)]) = true$$, and hence $$\mathcal{I}'$$ is a model for $$F'$$. The above results can be used to transform a Formula into a set of clauses, its clause normal form:

Problem 6 (Predicate)
Let $$F$$ be a formula, $$x$$ a variable and $$t$$ a term. Then $$F[x/t]$$ denotes the formula which results from $$F$$ by replacing every free occurrence of $$x$$ by $$t$$. Give a formal definition of this three argument function $$F[x/t]$$,  by induction over  the structure of the formula $$F$$. $$\Box$$

Problem 7 (Predicate)
Show the following semantic equivalences: $$\Box$$
 * 1) $$\forall x (p(x) \to (q(x) \land r(x))) \equiv \forall x (p(x) \to q(x)) \land \forall x (p(x) \to r(x))$$
 * 2) $$\forall x (p(x) \to (q(x) \lor r(x))) \not\equiv \forall x (p(x) \to q(x)) \lor \forall x (p(x) \to r(x))$$

Problem 8 (Predicate)
Show the following semantic equivalences:
 * 1) $$(\forall x p(x)) \to q(b) \equiv \exists x (p(x) \to q(b))$$
 * 2) $$(\forall x r(x)) \lor (\exists y \lnot r(y)) \equiv (\forall x r(x)) \to (\exists y r(y))$$

$$\Box$$

Problem 9 (Predicate)
Show that for arbitrary formulae $$F$$ and $$G$$, the following holds: $$\Box$$
 * 1) $$\forall x (F \lor G) \not\equiv \forall x F \lor \forall x G$$
 * 2) If $$G = F[x/t]$$, than $$G \models \exists x F$$.


text:
Scratch/Lessons/Downloading

Scratch code is almost entirely written using MIT's official editor, though some third-party editors exist as well. This editor can be used either offline or online. The online editor only features Scratch 3.0, but the offline editors for previous versions can still be downloaded. The online editor can be found at https://scratch.mit.edu/projects/editor. Information on the offline editor can be found below.

Scratch 3.0
The Scratch offline editor can be downloaded free of charge at https://scratch.mit.edu/download and the following operating systems are supported: Despite not being officially supported, the offline editor can be ran on Windows 7 as well.
 * Windows logo - 2012 (dark blue).svg Windows 10 or later
 * MacOS logo (2017).svg macOS 10.13 or later
 * Google Chrome icon (February 2022).svg ChromeOS
 * Android Robot Head 2023.svg Android 6.0 or later (tablets only)

Scratch 2.0
Scratch 2.0 is still available for download on the Scratch website. Scratch 2.0 also requires Adobe AIR. The following operating systems are supported:

 * Windows XP or later
 * Mac OS X 10.4 Tiger Logo.png Mac OS X
 * Tux.svg Linux distributions such as Fedora 13, Ubuntu 10.10, and openSUSE 11.3

Scratch 1.4
Scratch 1.4 is still available for download at https://scratch.mit.edu/scratch_1.4 and is available for the following Operating Systems:

 * Windows Logo (1992-2001).svg Windows 2000 and later
 * Mac OS X 10.4 Tiger Logo.png Mac OS X version 10.4 through 10.14.6
 * Tux.svg Linux - in various 32 bit distribution flavors

A minimum of 120 megabytes of hard drive space are requested to hold the Scratch basic multimedia pack and software.

Screen pixel size should be 1024 x 768 or larger, thousands or millions of colors (16-bit color or greater)

There are some aspects of Scratch where CPU performance can be an issue, but basic computers capable of running any of the above operating systems should work for most simple Scratch projects. Scratch is likely to be on the default installation for the XO-1 computer, to give an example of the kind of computer capable of using this software.

Linux Version
A version of Scratch for Linux is available from the scratch website at http://info.scratch.mit.edu/Scratch_on_Linux

This is missing some features of the Windows and Mac versions of Scratch, but you are able to edit, create, and otherwise interact with Scratch using most of the blocks.

Forum threads about the Linux version of Scratch can be found here:

 * http://scratch.mit.edu/forums/viewtopic.php?id=21
 * http://scratch.mit.edu/forums/viewtopic.php?id=305

Network (LAN) issues in a classroom
Scratch can be installed successfully on a shared network hard drive or other data sharing device that is commonly found in a classroom setting. This can give your students an advantage of being able to share a larger variety of multi media resources, and perhaps even to share project ideas between students. Specific details would have to be worked out with your district network technology specialist.

Several instructors and the Scratch development team have been successful at networking access to the Scratch software, both on a Mac as well as on a PC (Windows) architecture. Some user management software may cause some additional problems, but somebody with some competence at dealing with networking issues ought to be able to resolve these issues.

Scratch forum threads dealing with this specific topic can be found at the following places:
 * http://scratch.mit.edu/forums/viewtopic.php?id=194
 * http://scratch.mit.edu/forums/viewtopic.php?id=210

It should be noted that the first version of Scratch (version 1.1) exhibited some buggy behavior in networking environments due to user permission management options. These bugs can usually be worked around, and mainly deal with trying to load or save files when user permission has been denied. The "default" directories for both loading and saving files are sub-directories of the software folder itself. In this situation, you may want to encourage students to load and save through the documents folder. Most of these problems appear to have been fixed in v1.2.1.

Embedding Scratch
A Java applet has been written for use with Scratch applications, allowing you to "embed" a Scratch project within a web page. This applet is demonstrated on the main Scratch website, but you can also copy this applet to be used on your own website or blog. If you have uploaded content to the Scratch website, you can click the embed link on the project page and copy the HTML to embed it.

Some information that goes into greater depth about hosting all of the files "locally" on your own web server can be found here:

 * http://scratch.mit.edu/forums/viewtopic.php?pid=584
 * http://scratch.mit.edu/forums/viewtopic.php?pid=763

Scratch Projects on a "Live CD-ROM"
If you plan on sharing Scratch projects, you may want to include the Scratch software together with the project you created. As Scratch is an interpreted language instead of something which is compiled, you must include the interpreter together with your projects. All of these files can be found in the installation directory of Scratch.

Mac OS X
In addition to the .sb files containing the projects you need

 * Scratch.app
 * Scratch.image
 * license.txt (to make sure that the people who get Scratch know the terms of use of this software... a legal requirement)

The Help and locale subdirectories are probably also important

Windows
The following are some critical files that must be kept together with your Scratch project if you don't want to install the complete edition of Scratch on somebody else's computer:

 * Scratch.exe
 * Scratch.image
 * Scratch.ini
 * ScratchPlugin.dll
 * Mpeg3Plugin.dll
 * license.txt (to make sure that the people who get Scratch know the terms of use of this software... a legal requirement)

While not a "requirement", you have a couple of options to make it easier for somebody to start your project right away:

Create a "batch file" for your project
All you need to do here is to open a text editor like "Notepad" or "Wordpad" and type something like this line:

Scratch.exe Scratch.image project.sb

Substitute the name of your project that you want to share with the name "project.sb"

Save this file with the name "clickme.bat" or some other name that also ends in ".bat". This creates a command line "batch file" which used to be common in MS-DOS, but is still used in Windows.

Create a Windows shortcut
Open Windows Explorer and create a new temporary folder where you are going to put all of these files before you put them on your CD-ROM.

Next, use the right mouse button and click in the folder space, selecting the option "New", and the sub-option "shortcut".

When it asks for the name of the file, type in the same information listed above that is inside the batch file.

Click on the "Next" button, and the shortcut file should be created by Windows.

Finally, type in what you want to call this shortcut. Something simple like "Click Me" or "My Cool Project" is suggested.

title: Scratch/Lessons/Downloading


text:
Talk:Scratch/Lessons/Downloading

Source
Source material for the system requirements came from: http://scratch.mit.edu/forums/viewtopic.php?id=286

Any changes or updates to this information should be posted on this thread, but it may be wise to look elsewhere on the Scratch website in the future. --Rob Horning 18:08, 27 May 2007 (UTC)

The original thread about creating a Live CD-ROM: http://scratch.mit.edu/forums/viewtopic.php?id=243

Thanks Andres! --Rob Horning 16:37, 28 May 2007 (UTC)

Update to Scratch 2.0
I am updating the page to reflect Scratch 2.0, while leaving a not at the bottom describing Scrathc 1.4 differences. Any objections to this? Blackhat999 (discuss • contribs) 21:38, 11 November 2015 (UTC)

title: Talk:Scratch/Lessons/Downloading


text:
Macroeconomics/Market Economics

Market Economics concerns the study of forces within, and affecting, the varying markets of an economy.

title: Macroeconomics/Market Economics


text:
Muggles' Guide to Harry Potter/Magic/Bubble-Head Charm

Overview
The Bubble-Head Charm makes a pocket of breathable air about the caster's head.

Extended Description
This charm has been seen used in two places so far.

In Harry Potter and the Goblet of Fire, Cedric and Fleur use the Bubble-Head Charm in the Second Task. This charm allows them to survive underwater, giving them breathing air, for the time necessary to carry out their task.

In Harry Potter and the Order of the Phoenix, after Dolores Umbridge is appointed Headmaster, discipline at the school falls apart. Because she is afraid that the teachers might act to undermine her, Umbridge basically removes any authority they have, which leaves her and Filch the impossible task of maintaining discipline in a school of possibly 680 adolescent witches and wizards. While teachers can maintain order in their individual classrooms, nobody will take responsibility for the hallways, which become littered with dungbombs, which Filch, being a Squib, is largely powerless to clean up. It becomes common practice for the students to use a Bubble-Head Charm on themselves between classes, because the hallways smell so bad.


text:
Materials in Electronics/Confined Particles/Parity

Parity in 1 Dimension
Parity is one dimension is essentially a statement of the wavefunction's "evenness" or "oddness". This is how the wavefunction behaves when it is reflected about the point x=0:

Parity is important in scenarios such as the 1D finite square potential well. Because the well is symmetrical about its midpoint, it follows that the electron's probability density is also symmetrical about the midpoint (i.e. even). Recall that the probability density is given by the wavefunction multiplied by its conjugate. The statement of the evenness of the porobability is therefore:

 * $$\psi\left(x \right)^* \psi\left(x \right)=\psi\left(-x \right)^* \psi\left(-x \right)$$

The theory of even and odd functions shows that either an odd or even function multiplied by itself yields an even function, but a linear compination will not. Therefore, this condition can only be fulfilled if the wavefunction parity is either even or odd. It cannot be fulfilled if the wavefunction parity is a linear combination of even and odd functions, as this kind of combination produces neither an even or odd function.

 * {| width="100%" style="background-color: #F3F3FF; border: solid 2px #D6D6FF; padding: 1em;" valign="top"

 * Generally speaking, any wavefunction must have a definite parity with respect to the symmetry of the physical system
 * }


text:
Talk:General Astronomy/Motion and Gravity

please help me answer the following question.

Between which particles would an electric force of attraction occur?


text:
User talk:Kwilliamszaf~enwikibooks

Welcome message
Hello, welcome to Wikibooks!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be a good idea to add this page to your "watchlist" so that you can see when any new information is posted there. You can do that by clicking the tab labeled "watch" at the top of the page.

Good luck!

You might also be interested to read our Cookbook policy page, and talk to other Cookbook editors. Webaware talk 23:41, 27 May 2007 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Kwilliamszaf. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Kwilliamszaf~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:21, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:11, 19 April 2015 (UTC)

title: User talk:Kwilliamszaf~enwikibooks


text:
User talk:61.88.131.150

Regarding edits made during May 28 2007
Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you. If this is an IP address, and it is shared by multiple users, ignore this warning if you did not make any unconstructive edits. Az1568(Talk) 01:10, 28 May 2007 (UTC)

 * This is your last warning. Knock it off, or you will be blocked.  --Jomegat 02:13, 8 June 2007 (UTC)

title: User talk:61.88.131.150


text:
HSC Physics/Core/From Ideas to Implementation

Contextual Outline
Text excerpt is from Physics Stage 6 Syllabus

By the beginning of the twentieth century, many of the pieces of the physics puzzle seemed to be falling into place. The wave model of light had successfully explained interference and diffraction, and wavelengths at the extremes of the visible spectrum had been estimated. The invention of a pump that would evacuate tubes to 10−4 atmospheres allowed the investigation of cathode rays. X-rays would soon be confirmed as electromagnetic radiation and patterns in the Periodic Table appeared to be nearly complete. The nature of cathode rays was resolved with the measurement of the charge on the electron soon to follow. There was a small number of experimental observations still unexplained but this, apparently complete, understanding of the world of the atom was about to be challenged. The exploration of the atom was well and truly inward bound by this time and, as access to greater amounts of energy became available, the journey of physics moved further and further into the study of subatomic particles. Careful observation, analysis, imagination and creativity throughout the early part of the twentieth century developed a more complete picture of the nature of electromagnetic radiation and matter. The journey taken into the world of the atom has not remained isolated in laboratories. The phenomena discovered by physicists have, with increasing speed, been channelled into technologies, such as computers, to which society has ever-increasing access. These technologies have, in turn, often assisted physicists in their search for further knowledge and understanding of natural phenomena at the sub-atomic level. This module increases students’ understanding of the history, nature and practice of physics and the applications and uses of physics, the implications of physics for society and the environment, and the current issues, research and developments in physics.

Chapters

 * /Cathode Rays/ [[File:00%.svg]]
 * /Photoelectric Effect and Black Body Radiation/ [[File:00%.svg]]
 * /Transistors/ [[File:00%.svg]]
 * /Superconductivity/ [[File:00%.svg]]


text:
User:JCGonzales~enwikibooks

See my user page at Academia Wikia on academic publishing.

title: User:JCGonzales~enwikibooks


text:
User talk:24.111.217.145

Regarding edits made during May 28 2007
Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you. If this is an IP address, and it is shared by multiple users, ignore this warning if you did not make any unconstructive edits. Az1568(Talk) 06:46, 28 May 2007 (UTC)

title: User talk:24.111.217.145


text:
User talk:Gurbir-27

Hereby being a new member of this prestigious site, i would like to introduce myself as a student which is very keen to know about latest as well as past articles, offers,news , life, & many more amazing ventures and exciting offers related to my concerned bussinesss............ Iam Gurbir Singh of India,Jharkhand.,Ranchi Iam a student who is in class 10th of Bishop Westcott Boys' School ,Namkum.it is affiliated to  ICSE sllyabus.... therefore i want to take the help of this site in  my study matters...............

title: User talk:Gurbir-27


text:
Talk:Communication Theory/Propaganda and the Public

Shouldn't the Chomsky/Herman Propaganda Model be covered here? It certainly seems relevant. Mike.lifeguard 07:31, 28 May 2007 (UTC)


text:
Computational Chemistry

This book has been started using the initial author's teaching notes from a defunct university postgraduate molecular modelling course and it is hoped it will evolve into something useful and disguise its roots as other authors hack at it.

It will hopefully differentiate itself from an encyclopedia by having a practical rather than reference standpoint and will include a collection of problems.

Introduction
Computational chemistry covers a range of chemical applications such as quantum chemistry, molecular dynamics, molecular modelling, molecular mechanics and chemical informatics. Chemical informatics involves very large databases and information retrieval and data mining. Quantum chemistry is heavy computation and hard mathematics. Molecular dynamics is also heavy computation with hard but classical Newtonian mathematics!

Computational chemists cannot get enough computer time to try and simulate chemical reality as the variety of molecules is infinite and there are a lot of molecules in even a tiny drop of water. However making your simulation match reality requires a complex model and interpreting the data from hours of computer time to yield useful knowledge is difficult.

Contents

 * /Molecular mechanics/
 * /Molecular dynamics/
 * /Molecular quantum mechanics/
 * /Semiempirical quantum chemistry/
 * /Geometry optimization/
 * /Applications of molecular quantum mechanics/
 * /Applications of molecular modelling/
 * /Chemical informatics/
 * /Data bases and modelling/
 * /Macromolecular chemistry/
 * /Drug Design/
 * /Continuum solvation models/
 * /At the edge of Biology, Genomics and Proteomics/
 * /Bibliography/

title: Computational Chemistry


text:
User:Jeandré du Toit

Previously User:Jeandré here on wikibooks.

w:User:Jeandré du Toit

title: User:Jeandré du Toit


text:
HSC Physics/Core/From Ideas to Implementation/Cathode Rays

Introduction
Cathode rays are streams of electrons emitted in a evacuated tube known as a cathode ray tube or a discharge tube. The cathode rays flow from the cathode (negative electrode) to the anode (positive electrode). It is possible to deflect the path of the rays using electric and magnetic fields. This has lead to its use in many applications including the television and the computer.


text:
Belarusian/Lesson 6

Soft Consonants
Most consonants in Belarusian have two modifications: hard and soft.

Consonants are pronounced softly before y-vowels, е, ё, і, ю or я. In such a position (after consonsants) these vowels loose their й and pronounced as э, о, і, у or а respectively.

In English, something similar to "hard-soft" phenomenon also takes place. E.g., l in purple is more like Belarusian hard л while in please it is pronounced like soft л. But in Belarusian these modifications are considered as different phonemes, i.e. their mispronounciation may result in misunderstanding and word confusion.

бэз "bez" - lilac; без "biez" - without

лук "luk" - a bow; люк "liuk" - a hatch

Soft consonants are pronounced with your tongue moved up and forward relative to its position when pronouncing the hard sound. It is something like pronouncing an extremely short і sound after the consonant.

Ве́на "V(i)ena" - Vienna

вёска "v(i)oska" - a village

лю́стра (neuter) "l(i)ustra" - a mirror

The consonants дж, ч, дз, ц, ж, ш and р are always hard (зацвярдзе́лыя "zatviardielyya"). Consequently, дж, ч, ж, ш and р can never be followed by е, ё, і, ю or я.

The sound й is a soft sound, and it has no hard mate. As was already mentioned before, it can never be followed by a vowel.

L in Borrowings: Soft of Hard?
There is a remarkable difference between tarashkievitsa and narkamauka in spelling and pronunciation of a number of borrowed words. Such words having an l+vowel combination in the original language have hard л in narkamauka and soft л in tarashkievitsa.

However, li and le are transliterated as лі and ле in both variants.

In some borrowings, especially German and French, л is soft in both variants: люк a hatch, лю́мпен a lumpen, a social outcast element, лю́стра a mirror.

The word пала́ц (a palace) is spelled the same in tarashkievitsa (though it might be spelled as паляц according to this rule).

Soft Noun And Adjective Endings
Nouns ending by я (usually feminine), е or ё (neuter) in plural end by і.

до́ля a part, a share - до́лі

по́ле a field - палі

Note that neuter nouns ending by е can have a stressed ending in plural.

The plural і ending is also obtained by nouns ending by к, ка, г, га, х, ха.

рака́ a river - рэ́кі

даро́га a road - даро́гі

кніга a book - кнігі

саба́ка a dog - саба́кі

вёска a village - вёскі

чарапа́ха a turtle - чарапа́хі

бык a bull - быкі

выкла́дчык a lecturer - выкла́дчыкі

Soft adjective endings are as follows.

If the ending of an adjective is preceded by к, г or х, its flexions are as follows.

Pronunciation: Soft Consonants
Pronounce these words paying special attention to soft consonants.

Ве́нгрыя Hungary

Кіта́й China

вёска a village

лю́стра a mirror

Ме́ксіка Mexico (the country)

Ме́хіка Mexico (the city)

Фінля́ндыя Finland

Літва́ Lithuania

Gender
Make up three sentences with the given pair of words: "This is a "; "It/he/she is "; This is a ". Take note that nouns and adjectives must be coordinated by gender, i.e. masculine adjectives are used with masculine nouns etc.

Sample: village, old: Гэта вёска. Яна старая. Гэта старая вёска.

(1) mirror, new

(2) field, broad

(3) road, narrow

(4) river, beautiful

(5) lecturer, young

Clue: (1) Гэта люстра. Яно новае. Гэта новае люстра. (2) Гэта поле. Яно шырокае. Гэта шырокае поле. (3) Гэта дарога. Яна вузкая. Гэта вузкая дарога. (4) Гэта рака. Яна прыгожая. Гэта прыгожая рака. (5) Гэта выкладчык. Ён малады. Гэта малады выкладчык.

Number
Transform all sentences from the previous exercise into plural.

Sample: village, old: Гэта вёскі. Яны старыя. Гэта старыя вёскі.

Clue: (1) Гэта люстры. Яны новыя. Гэта новыя люстры. (2) Гэта палі. Яны шырокія. Гэта шырокія палі. (3) Гэта дарогі. Яны вузкія. Гэта вузкія дарогі. (4) Гэта рэкі. Яны прыгожыя. Гэта прыгожыя рэкі. (5) Гэта выкладчыкі. Яны маладыя. Гэта маладыя выкладчыкі.

Translation
Translate into Belarusian.

(1) These are beautiful fields.

(2) These are young secretaties.

(3) Who is this? This is a dog. It is old.

(4) This is a new church.

(5) I am young.

(6) You are ill.

Clue: (1) Гэта прыгожыя палі. (2) Гэта маладыя сакратаркі (сакратары). (3) Хто гэта? Гэта сабака. Ён стары. (4) Гэта новая царква. (5) Я малады (маладая). (6) Вы хворыя.

title: Belarusian/Lesson 6


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Cookbook:Grilled Aubergine

| Japanese Cuisine | Vegetarian

Ingredients

 * 1 ea. (375 g) large aubergine (eggplant)
 * Vegetable oil
 * 2 tablespoons miso paste
 * 1½ tablespoons sugar
 * 2 tablespoons soup stock
 * 1 teaspoon white sesame seeds

Procedure

 * 1) Wash the aubergine, and cut it into 2.5 cm slices lengthwise.
 * 2) Brush the cut surfaces with oil.
 * 3) Grill 7–10 cm from the source of the heat until the aubergine is tender and browned all over (about 5 minutes).
 * 4) In a small saucepan combine the miso, sugar, and soup stock. Cook, stirring, over low heat until the mixture is smooth and hot. Do not let it boil.
 * 5) Pour the sauce mixture over the aubergine.
 * 6) In a small frying pan toast the sesame seeds until they jump, then sprinkle them over the aubergine.

title: Cookbook:Grilled Aubergine


text:
Cookbook:Habas con Jamon (Broad Beans with Ham)

Ingredients

 * 300 g broad beans (fresh or canned)
 * 1 onion, sliced
 * 2 strips of ham or bacon (or vegetarian bacon)
 * Olive oil

Procedure

 * 1) Fry onions and ham in a pan with a little olive oil.
 * 2) Add the broad beans and sauté for a few minutes until the beans are soft.
 * 3) Serve hot.


text:
Usenet Explorer User's Manual

Usenet Explorer is a multi server, multi windows, multitasking newsreader for text and binaries. A powerful binary downloader, without compromising support for text. Supports virtual groups and grouping binary posts into collections. Has full download automation capabilities. Is fast and reliable. Includes a comprehensive Usenet binary indexing service.

/Features/
Multiserver, Multitasking, Virtual groups, Collections, NZB, Header filtering, Automation, SSL support, Fast and reliable, Indexing service

/User Interface/
Icons, Windows and panes, Toolbars, Editors, Keyboard shortcuts, Workspace, Task manager, Quick filter bar, Search service bar, Toolbar, Status bar, Filter editor

/Manual/
Quick Start, Installation, Configuration, Getting headers, Searching, Reading News, Downloading, Import NZB files, Filters, Automation, Tips & Tricks, FAQ

/Appendixes/
/Versions/, /Glossary/, /Index/, /References/

title: Usenet Explorer User's Manual


text:
User talk:Mmckenzie

Welcome message
Hello, welcome to Wikibooks!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be a good idea to add this page to your "watchlist" so that you can see when any new information is posted there. You can do that by clicking the tab labeled "watch" at the top of the page.

Good luck!

You might also be interested to read our Cookbook policy page, and talk to other Cookbook editors. Webaware talk 13:35, 28 May 2007 (UTC)

title: User talk:Mmckenzie


text:
Stress-related Disorders/Introduction

Stress - Brief Introduction
Q. Differentiation between Anxious and Stress.

It is not very grammatically correct to write in patients chart- "Looks anxious" and referring them to psychiatric ward/PSY-consultation. Stress is not an anxiety (anxiety disorder), they are not synonymous.

A general concept/understanding in Human-psychology/Psychiatry is beneficial.

Q. When is stress experienced?

A person typically is stressed when they experiences positive or negative temporarily strain or overwhelm adaptive capacities.

In general - Stress can be physiological or pathological. A general concept/understanding in them is beneficial.

Q. Who can get Stress?

Stress is highly individualized and depends on variables such as the novelty, rate, intensity, duration, or personal interpretation of the input, and genetic or experiential factors.

For an example
 * Panic attacks are more frequent when the predisposed person is exposed to stressors.

Q. What to do if you encounter stressed person in surgical ward?

Ultimate refer place is psychiatric consultation, But... pre-PSY-consultation, we can provide our little help.

Q. Which stress remedies are in fashion?

 * Stress-reduction strategies can be helpful to many stressed/anxious patients/sufferer.
 * Unfortunately, many stressed/anxious persons cannot concentrate enough to use such strategies effectively for acute relief.
 * Most stress-reduction techniques have their greatest utility as elements of a prevention plan that attempts to raise one's threshold to anxiety-provoking experiences.

title: Stress-related Disorders/Introduction


text:
User:AFUSCO~enwikibooks

This user is rarely here please visit my page on Wikipedia

title: User:AFUSCO~enwikibooks


text:
Cookbook:Taro Fish

| Chinese Cuisine | Vegetarian

Ingredients

 * 1 small taro
 * 2 sheets nori
 * 1 tsp preserved black beans
 * 2-inch piece of ginger
 * 1 green pepper
 * 2 spring onions
 * 1 tsp vegetable stock powder
 * 2 tbsp Shaoxing rice wine
 * Vegetable oil

Procedure

 * 1) Peel and chop taro into 1-inch chunks. Steam until soft.
 * 2) Meanwhile soak black beans in a little water.
 * 3) Mash taro with the vegetable stock powder.
 * 4) Place 2 sheets of nori on the bench, moistening one to join them together.
 * 5) Place the mashed taro mixture in the centre of the sheets and roll the nori sheets over the top.
 * 6) Cut the nori at one end to resemble fish fins.
 * 7) Slice green pepper, ginger and spring onions into thin strips and stir fry for a few minutes.
 * 8) Add the Shaoxing wine and black beans.
 * 9) Make cuts halfway through the taro fish at about 1 inch intervals and pour the sauce over it.
 * 10) Serve on a platter.

title: Cookbook:Taro Fish


text:
Stress-related Disorders/Anxiety Reduction

 The Five Rs of Stress/Anxiety reduction

The five core concepts used in the reduction of anxiety or stress:

 * 1) Rcognition of the causes and sources of the threat or distress; education and consciousness raising.
 * 2) Relationships identified for support, help, reassurance
 * 3) Removal from (or of) the threat or stressor; managing the stimulus.
 * 4) Relaxation through techniques such as meditation, massage, breathing exercises, or imagery.
 * 5) Re-engagement through managed re-exposure and desensitization.


text:
Stress-related Disorders/Relaxation Response

A Technique for Promoting the Relaxation Response

 * 1) Basic elements
 * 2) *A quiet environment
 * 3) *A comfortable posture
 * 4) *A mental device
 * 5) **A mental device (a meaningful word or phrase)
 * 6) *A passive attitude
 * 7) Instructions
 * 8) *In a quiet environment
 * 9) **In a quiet environment, sit in a comfortable position.
 * 10) Close your eyes
 * 11) *Deeply relax all your muscles
 * 12) **Deeply relax all your muscles, beginning at your feet and progressing up to your face (i.e., feet, calves, thighs, lower torso, chest, shoulders, neck, hand). Allow them to remain relaxed.
 * 13) *Breathe through your nose
 * 14) **Become aware of your breathing. While breathing out, say silently to yourself the word "one" ("won") or some other word or short phrase that is meaningful to you (i.e., breathe in; breathe out, saying "won"; breathe in; breathe out, saying "won").
 * 15) *Continue this way for 20 minutes
 * 16) **You may open your eyes periodically to check the time, but do not use an alarm. Do this once or twice daily and not within 2 hours after any meal.
 * 17) *When you finish each 20-minute exercise
 * 18) **When you finish each 20-minute exercise, sit quietly for a few minutes, first with your eyes shut and then with them open.
 * 19) *The goal is a passive attitude
 * 20) **Deep relaxation will not always occur, and distracting thoughts will come into your mind. When you become conscious of them, ignore them and sustain the breathing exercise.

Source
Adapted from Benson H. The Relaxation Response. New York: Morrow, 1975; and Benson H, Beary JF, Carol MP. The relaxation response. Psychiatry 37:37-46, 1974.


text:
Stress-related Disorders/Defenses

 Defenses

 Defense mechanism

Behavior patterns primarily concerned with protecting ego. Presumably the process is unconscious and the aim is to fool oneself.
 * It is intrapsychic processes serving to provide relief from emotional conflict and anxiety.
 * Conscious efforts are frequently made for the same reasons, but true defense mechanisms are unconscious.
 * Some of the common defense mechanisms are:
 * 1) Compensation
 * 2) Con-version
 * 3) Denial
 * 4) Displacement
 * 5) Dissociation
 * 6) Idealization
 * 7) Identification
 * 8) Incorporation
 * 9) Introjection
 * 10) Projection
 * 11) Rationalization
 * 12) Reaction formation
 * 13) Regression
 * 14) Sublimation
 * 15) Substitution
 * 16) Symbolization
 * 17) Undoing

Repression/suppression
"One way to deal with emotional pain is to not think about what has happened." With practice, this becomes an automatic process, we really don't remember what we did or what happened. This is repression.
 * We put it out of our mind.
 * We forget it.

Unconscious (unintentional) blocking of thoughts and experiences is repression. Voluntary blocking of thoughts and experiences is suppression.

Displacement
"Displacement is simply taking an emotion that belongs in one situation and displaying it in another."

The most common emotions which are displaced are:
 * 1) Anger.
 * 2) Hostility.

Example of Displacement: Imagine, for a moment, that you have had a rough day at work.

 * 1) Your boss has chewed you out, and you are angry about it.
 * 2) It's not safe to take out your anger on your boss. You might be fired.
 * So, when you get home, you yell at the kids and beat your wife.

That's displacement.

Projection
"Projection is the process of taking feelings we have about ourselves (usually painful feelings) and focusing them on other people."

Examples of Projection:

 * 1) A person who fears he is drinking too much may point out another person who is drinking and put him down for being a drunk.
 * 2) A man or woman who has been cheating on his/her spouse may accuse the spouse of being unfaithful.

Types of Projection: Blame is a form of projection. Examples of blame:
 * 1) An individual, concerned about his drinking, may blame his parents for the way they raised him, or his wife for the way she treats him.
 * 2) Eventually the alcoholic comes to hate himself, but he finds this emotional state too much to bear so he expresses this as hatred for those closest to him, usually his wife and children.

Denial
"Denial is the refusal to believe or accept the reality that certain events have happened (are happening) or will happen."

 * To accept the reality would bring emotional pain, so the events are denied.
 * This is the single most common psychological symptom of chemical dependency.

Co-Relation: Related to denial is the defense called minimizing.

Minimizing:
Events are accepted, but only in a watered down version. Example: Sure I drink once in a while. Everybody does. It's no big deal. Once in a while I might get carried away, but it really isn't a problem.

Withdrawal
"Withdrawal is usually used when a person is afraid of rejection or afraid to fail."

 * By withdrawing the person is attempting to avoid psychological pain.
 * The problem is it inevitably leads to strong feelings of loneliness, and it does nothing for the original fears.

Withdrawal takes several forms. Most common are: But the use of drugs and excessive sleeping (can) also occur.
 * 1) Silence.
 * 2) Running away.

Co-Relation: Closely related to withdrawal are:
 * 1) Avoidance.
 * 2) Deflection.

NB! Many co-alcoholics use avoidance extensively. i.e., they won't talk about the problems at home and they stay away from others to avoid feelings of embarrassment, shame, etc.

Deflection:
"Deflection is a method of changing a subject that is or might be painful."

Commonest methods of deflection are: These are the two of the most common methods of deflecting people away from difficult subjects.
 * 1) Humor
 * 2) Anger

Alcoholics frequently combine deflection and projection through the use of anger and hostility.

Rationalization
"Rationalization is to justify your behavior or to make excuses for your behavior."

Examples:
 * 1) The alcoholic, arrested for impaired driving, may tell himself, and everybody else, that the RCMP are out to get him.
 * 2) A person may fail to get a job he has applied for, and then tells people it was really a crummy job anyway and he didn't really want it.

Fantasy
"When the world of everyday life becomes too painful or difficult too bear, some people turn to the inner world of fantasy."

 * Day dreaming and wishful thinking replace action.
 * Combined with avoidance you get retreats into fiction via books and/or TV.

NB! Alcoholics often combine rationalizing and fantasy. The result is: "IF ONLY... Syndrome"

 * 1) If only I had money...
 * 2) If only I didn't have a wife and children...
 * 3) If only I could do what I want...
 * 4) If only people understood me...
 * 5) If only I were younger (older)...

Intellectualization
"In order to avoid experiencing his real feelings a person may discuss his problem(s) in an analytical, rational, intellectual way."

Risk: 1. This is common among college educated people and alcoholism counsellors who have fallen off the wagon. 2. This defense often frightens or repels other people leading to isolation and a strong sense of loneliness.

Procrastination
"Procrastination is another way to avoid painful feelings by convincing yourself that a problem can be dealt with later."

"I'll look for work tomorrow." "I'll stop drinking tomorrow." "I'll get the car fixed after I get a job."

Reaction-formation
"This defense is simply faking your feelings or expressing the opposite of what you really feel."
 * This process can become so automatic that you actually do not know what your true feelings are.

Summary
The major function of these psychological defenses is to prevent the experiencing of painful emotions.
 * There are several major problems with their use.

First:
Many of these defenses create new problems that are as bad, or worse, than the emotional problems they mask.
 * Some are just plain destructive.
 * Example:
 * Rejection literally destroys the relationships we care most about.

Second:

 * These defenses distort our ability to perceive reality as it is.
 * And this prevents us from dealing with our problems in a constructive way.

Third:

 * These defenses do not rid us of the painful feelings we have.
 * In fact, by masking them so that we do not feel them, we effectively store them up within ourselves.

 * Emotions are discharged through expression, so by denying ourselves the chance to feel them, we also deny ourselves the ability to get rid of them.

Fourth:

 * These defenses do not just screen out painful emotions. They are, in fact, defenses against all emotion.

painful feelings, the less able we are to experience the joyful and happy feelings that make life worth living.
 * So the more effective our defenses become in protecting us from our

Finally:

 * These defenses are not perfect.

 * As more and more hurt is stored away, a tension is developed.
 * We become increasingly anxious, nervous, and irritable.
 * We become emotionally unpredictable.

 * And when our defenses weaken, as they will from time to time, we experience emotional explosions.

Ultimately:

 * These defenses prevent us from knowing what is wrong, but they do not prevent us from feeling bad.

Source

 * http://www.shrinktank.com/ftp/defenses.zip
 * defenses.txt

title: Stress-related Disorders/Defenses


text: File:Ue logo.gif

title: File:Ue logo.gif


text:
User talk:Stan.a

Hello, welcome to Wikibooks!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be a good idea to add this page to your "watchlist" so that you can see when any new information is posted there. You can do that by clicking the tab labeled "watch" at the top of the page.

Good luck! -- Herby talk thyme 15:39, 28 May 2007 (UTC)

Image copyright problem with Image:Ue logo.gif
Thanks for uploading Image:Ue logo.gif. However, the image may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

The copyright holder is usually the creator, the creator's employer, or the last person who was transferred ownership rights. Copyright information on images is signified using copyright templates. The three basic license types on Wikibooks are open content, public domain, and fair use. Find the appropriate template in Image copyright tags and place it on the image page like this:.

Please signify the copyright information on any other images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, feel free to contact me, or ask them at the Study help desk. Thank you. -- Herby talk thyme 15:50, 28 May 2007 (UTC)

title: User talk:Stan.a


text:
Usenet Explorer User's Manual/Versions

This chapter contains the change log of Usenet Explorer.

The primary source of information for this page is the Usenet Explorer Forums Release history.

v2.2.1
Released 26 August 2008.

v2.2
Released 18 July 2008.

v2.1.5
Released 17 July 2008.

v2.1.4
Released 13 July 2008.

v2.1.3
Released 8 July 2008.

v2.1.1
Released 3 July 2008.

v2.1
Released 2 July 2008.

v2.02
Released 8 June 2008.

v2.01
Released 6 June 2008.

v2.0
Released 25 May 2008.

v1.9.9.8
Released (unknown).

v1.9.9.7
Released 10 November 2007.

v1.9.9.5
Released 8 November 2007.

v1.9.9.3
Released 7 November 2007.

v1.9.9.2
Released 29 October 2007.

v1.9.9.1
Released 27 October 2007.

v1.9.9
Released 1 September 2007.

v1.9.8
Released (unknown).

v1.9.7
Released 23 July 2007.

v1.9.6
Released 14 July 2007.

v1.9.5
Released 17 June 2007.

v1.9.2
Released 17 June 2007.

v1.9.1
Released 1 June 2007.

v1.9
Released 26 May 2007.

 * Introduction of Custom Collections.

v1.8
Released 14 May 2007.

- search service protocol has been changed to address future needs

- quick filter "find mode" match cyan color oval sign now is shown in the newsgroup list as well

this release is the concluding conservative release in the series to secure last changes before proceeding with further development

v1.7.7
- fixed accidentally disabled dragging newsgroups between folders while refining multiple selection workspace view code.

- this completes the latest series of updates resolving all small issues and user requests as the development is now moving to larger onces.

v1.7.6
- size left is shown along with time left in the status bar enable the status bar using View > Status bar

- added right/left arrow keys shortcuts in addition to plus/minus sign to expand/collapse threads and collections in newsgroup views to expand threads and collections in newsgroup view press or +, to collapse press <- or -

- further refined multiple selection code in vista plus now it is possible to select several areas like in newsgroup view using e.g. ctrl+mouse then shift+mouse

- fixed non-working context "newsgroup list" submenu from within newsgroup list view

- ssl access now can connect through a proxy server (edit menu->properties->proxies)

title: Usenet Explorer User's Manual/Versions


text:
User:Minestrone Soup~enwikibooks

Hello there!

title: User:Minestrone Soup~enwikibooks


text:
User talk:Minestrone Soup~enwikibooks

Hello, welcome to Wikibooks!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be a good idea to add this page to your "watchlist" so that you can see when any new information is posted there. You can do that by clicking the tab labeled "watch" at the top of the page.

Good luck! -- Herby talk thyme 16:22, 28 May 2007 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Minestrone Soup. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Minestrone Soup~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:30, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:15, 19 April 2015 (UTC)

title: User talk:Minestrone Soup~enwikibooks


text:
Semiconductors/Introduce to Transistor

Intro
A Transistor is an electronic component created by joining two types of semiconductors. One type of semiconductor is "P-type" and the other is "N-type". Bipolar transistors have 3 terminals : Base, Collector, Emitter. Transistors are commonly used in amplification, switching, and buffering signals or applied voltages.

The two types of bipolar-junction transistors (BJTs) can be constructed from 2 configurations below 1) A P-type region lies between 2 N-Typed Semi Conductors . This kind of configuration is called NPN Transistor
 * [[image:NPN BJT.svg|400px]]    [[image:BJT symbol NPN.svg|75px]]

2) An N-type region lies between 2 P-Typed Semi Conductors . This kind of configuration is called PNP Transistor.
 * [[image:PNP BJT.svg|400px]][[image:BJT symbol PNP.svg|75px]]

It is equivalent to two nose-to-nose diodes, but as before, just connecting two diodes will not work. Generally, a PNP diode is identical to an NPN diode, but with all currents reversed.

I-V Curve
I-V curve indicates transistor's current versus transistor's voltage
 * Current-Voltage_relationship_of_BJT.png

From I-V curve above
 * $$V < V_{BE} . I = 0$$ . Transistor is cut-off
 * $$V = V_{BE} . I = 1mA$$ . Transistor conducts current
 * $$V > V_{BE}. I = e^{V/V_d}$$ . Tranistor is active and provides amplified current
 * $$V = V_s . I = I_s$$ . Transistor is saturated

Với
 * $$V_{BE}=V_d$$
 * $$V_d=0.6$$ Silicon

Operating Modes
A bipolar transistor can be regarded as a current amplifier. The (small) base current is amplified by a factor (typically in the range of 10 to 500) to yield a proportionally larger collector current. But in order for a transistor to perform its task properly, there have to be voltages applied to make the transistor conduct current. These voltages are called bias voltages.

Depending on how the transistor is used, it can behave as a (relatively) linear amplifier or a switch.

A bipolar transistor has three terminals, base, emitter and collector, and two internal PN-junctions; the collector to base junction (CBJ) and the emitter to base junction (EBJ). A junction is conducting a significant amount of current in the forward direction (P to N) if the voltage across it is larger than a diode forward voltage drop (Vd), which is around 0.6 V in silicon. The operation of the transistor is largely affected by how the terminals are biased. The table below shows how to bias the base-emitter voltage (Vbe) and the collector-emitter voltage (Vce) to bring the transistor into the different modes. The table shows the voltages for a silicon NPN transistor:

When a transistor operates in the active mode it will act as an amplifier meaning that a small change in base current will cause a proportional change in collector current. In the active mode, the EBJ is conducting and the collector to emitter voltage is bigger than the collector to emitter saturation voltage (Vcesat). Typically, Vcesat is around 0.2V.

When a transistor operates in the cut-off and saturation modes, it will act as a switch. In the cut-off mode, there is no base current and therefore no collector current. The collector voltage is not important as long as it is larger than the emitter voltage. In the saturation mode, the transistor is fully on, meaning that an increas in base current does not result in any significant increase in collector current.

The reverse active mode is normally not used. This mode occurs if the emitter and collector terminals are swapped for a transistor in the active mode so that emitter and collector change roles. Based on the descriptions of a transistor given so far, one might expect that a transistor is symmetrical and that it would work identically with collector and emitter swapped. However, the physical design of real transistors is such that the current amplification is much smaller in the reverse active mode compared to the forward active mode, although it is still typically larger than one. This can be useful knowledge when troubleshooting a prototype circuit. If it seems to act as if the gain of the transistor is too low, it might be due to swapped emitter and collector terminals.

/NPN/ Transistor

 * /NPN/4R1T/
 * /NPN/2R1T/

/PNP/ Transistor

 * /PNP/4R1T/
 * /PNP/2R1T/

title: Semiconductors/Introduce to Transistor


text:
Wikijunior talk:Human Body/Medical - Laparoscopic Surgery

This topic doesn't seem to fit into the outline for this book. Suggest possibly moving into another book. Kfasimpaur 16:39, 28 May 2007 (UTC)


text:
Wikijunior:Human Body/Digestive System/Large Intestine

The large intestine is the final part of the digestive system. In the large intestine, digestion is finished, and nutrients continue to be absorbed. Finally, wastes get ready to leave the body.

What does the large intestine look like?
The large intestine is fatter and shorter than the small intestine. It is about 2.5 inches (6.4 cm) wide and 5 feet (1.5 meters) long. It wraps around the small intestine like an upside-down U.

What are the parts of the large intestine?
The large intestine is shaped like an upside-down horseshoe. The left side that goes up is called the ascending colon. The part that goes across the top is the transverse colon. The part that goes back down is the descending colon. At the end of this is the rectum. This is the opening through which waste leaves the body.

What is the function of the large intestine?
The large intestine finishes digesting food. Food stays in the large intestine longer than any other part of the digestive system. Food can be there for up to a whole day or more. Any remaining nutrients are absorbed into the blood. Most of the rest of the liquid that enters the large intestine is water. Much of this is absorbed into the blood as well.

Whatever is left is waste, or feces. This passes out of the body when you go to the bathroom.

How does the large intestine interact with other parts of the body?
The large intestine is connected to the small intestine. Though not as long as the small intestine the large intestine plays more of an important role in the digestive system. Watery food comes from the small intestine into the large intestine.

Minerals and water are absorbed from the large intestine into the blood. Then they can be used by the rest of the body.

Attached to the large intestine is an organ called the appendix. It doesn't do anything that we know of. Sometimes, it gets infected it and must be removed before it bursts, ultimately killing you.


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Semiconductors/Introduce to Transistor/NPN/4R1T

Transistor Configuration

 * [[Image:Transistor_amplifier_blocked_emitor.svg|200px]]

Formula

 * $$V_B = V_i \frac {R_2} {R_2 + R_1}$$
 * $$V_E = V_B - 0.7 = V_B$$
 * $$I_E = \frac {V_E} {R_4} = \frac {V_B} {R_4}$$
 * $$I_C = I_E$$
 * $$V_C = I_C R_4$$
 * $$V_C = V_i (1 - \frac {R_3} {R_4} \frac {R_2}{R_2 + R_1})$$

Analysis
1 ) R2 >> R1
 * $$V_C = V_i (1 - \frac {R_4} {R_3})$$
 * R4 = 0 . VC = 0
 * R4 = R3 . VC = 0
 * R4 = 2 R3 . VC = -Vi
 * R4 = 3 R3 . VC = - 2 Vi

 * R4 = n R3 . VC = - (n-1) Vi

 * 1) PNP hoạt động như một khuếch đại âm . Điện  thế xuất là một điện thế âm bằng với điện thế nhập khuếch đại (n-1)
 * 2) Vậy khi chọn R2 >> R1, R4 = n R3 thì ta được VC = - (n-1) Vi

2 ) R4 = R3
 * $$V_c = V_i (1 - \frac {R_2}{R_2 + R_1})$$

 * R2 = 0 . Vc = Vi
 * R2 = R1 . $$V_c = V_i\frac{1}{2} $$
 * R2 = 2 R1 . $$V_c = V_i\frac{2}{3} $$
 * R2 = 3 R1 . $$V_c = V_i\frac{3}{4} $$

 * R2 = n R1 . $$V_c = V_i\frac{n}{n+1} $$

'''.
 * 1) 'PNP hoạt động như một khuếch đại dương'' . Điện thế xuất là một điện thế dương bằng với điện thế nhập khuếch đại $$\frac{n}{n+1}  $$
 * 1) Vậy khi chọn R4 = R3 và R2 = n R1 thì ta được $$V_C = V_i [\frac {n}{n+1}]$$.

3) R2 = 0 . VC = Vi
 * R2 >> R1 . VC = 0

 * 1) PNP hoạt động như một công tắc . Mở khi R2 >> R1  . Đóng khi R2 = 0'''
 * 2) Vậy khi chọn R2 = 0, R2 >> R1 thì ta được một công tắc

4 ) R4 = R3=R2 = R1 = R
 * $$V_C = V_i [\frac {1}{2}]$$.

 * 1) Vậy khi chọn R4 = R3=R2 = R1 = R thì ta được $$V_C = V_i [\frac {1}{2}]$$.

Amplifier
From
 * $$V_C = V_i (1 - \frac {R_3} {R_4} \frac {R_2}{R_2 + R_1})$$

If R2 >> R1

 * $$V_C = V_i (1 - \frac {R_3} {R_4}) $$
 * R3 = 0 . VC = Vi
 * R3 = R4 . VC = VC = 0
 * R3 = 2R4 . VC = -Vi
 * Rn = 3R4 . VC = -2Vi

 * R3 = nR4 . VC = -Vi(n-1)

 * When choosing value of the resistors such as R2 >> R1 và R3 = nR4 . VC = -Vi(n-1) .Transistor acts as a Negative Amplifier with the ratio of amplification is (n-1) . The output voltage is a negative voltage equals to the input voltage amplied by a factor of (n-1)

Switch
From
 * $$V_C = V_i (1 - \frac {R_3} {R_4} \frac {R_2}{R_2 + R_1})$$

If R3 = R4
 * $$V_C = V_i (1 - \frac {R_2}{R_2 + R_1})$$

When choosing resistor's values such as
 * R2 >> R1 . VC = 0
 * R2 = 0 . VC = 1

 * Transistor acts as a Switch
 * Open when R2 >> R1 . VC = 0
 * Close when khi R2 = 0 . VC = 1

Negative Buffer
From
 * R3 = nR4 . VC = -Vi(n-1)

 * If R3 = 2R4..
 * VC = -Vi.
 * Transistor acts a Negative Buffer. VC = -Vi. The output voltage is a negative voltage equal to the input voltage

Positive Buffer
From
 * $$V_C = V_i (1 - \frac {R_3} {R_4} \frac {R_2}{R_2 + R_1})$$

 * If R2 >> R1

 * $$V_C = V_i (1 - \frac {R_3} {R_4}) $$
 * R3 = 0 . VC = Vi
 * Transistor acts a Positive Buffer. The output voltage is a positive voltage equal to the input voltage

 * If R3 = R4

 * $$V_C = V_i (1 - \frac {R_2}{R_2 + R_1})$$
 * R2 >> R2 . VC = Vi
 * Transistor acts a Positive Buffer. The output voltage is a positive voltage equal to the input voltage

Voltage Divider
From
 * $$V_C = V_i (1 - \frac {R_3} {R_4} \frac {R_2}{R_2 + R_1})$$

 * If R1 = R2 = R3 = R4 = R
 * V_C = ½ V_i
 * The output voltage is exactly half of the input voltage


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Wikijunior:Human Body/Digestive System/Small Intestine

The small intestine is a part of the digestive system. It is the most important organ for the digestion of food.

What does the small intestine look like?
The small intestine is a long, narrow tube that is all coiled up in the lower part of our abdomen (the part of our body we usually call our "stomach"). It is over 20 feet (6 meters) long! This is the largest part of the digestive system. The only way the small intestine can fit into our bodies is by curling and looping to fit in a small space.

What are the parts of the small intestine?
The small intestine is about 20 feet long

The first part of the small intestine is called the duodenum. The middle part is the jejunum. This is where most of the nutrients in food are absorbed into the blood. The last part of the small intestine is called the ileum. This part connects to the large intestine.

The lining of the small intestine is covered with tiny finger-like projections called villi. They look almost like carpet. The villi help the nutrients in food to be absorbed into the blood.

What is the function of the small intestine?
The small intestine is where most digestion takes place. Food is broken down into smaller and smaller particles. Finally, when the particles are small enough, they are absorbed into the blood, and the blood carries the nutrients to all parts of the body.

How does the small intestine interact with other parts of the body?
The small intestine is connected to the stomach. Food that the stomach has begun to digest moves into the small intestine. After it moves through the small intestine, food moves on the large intestine. Like other organs, the small intestine gets oxygen from blood vessels. The blood in the small intestine also carries the nutrients from food to the rest of the body. The circulatory system allows this to happen.

The small intestine gets enzymes from two important glands, called the liver and the pancreas. The liver is the largest organ in our bodies. It makes a liquid called bile that helps digest fat. The bile is stored in another organ called the gall bladder. The pancreas makes a juice that breaks down sugars and starches.


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Wikijunior:Human Body/Digestive System/Stomach

The stomach is a part of the digestive system. It is where food is stored and where digestion continues after food is chewed and swallowed.

What does the stomach look like?
Many people think the stomach is near the belly button. However, it is really higher up. The stomach is behind the lower part of the ribs.

The stomach is a bag or pouch made of muscle. The stomach is a j-shaped organ. It is about the size of a grapefruit.... The stomach stretches when it is full of food. It also has an exit and an entrance.

What are the parts of the stomach?
At the top of the stomach is a tube where food comes in from the esophagus. When you swallow, this tube opens so food can go in the stomach.

The stomach is made of muscle. These muscles help to break down food by mashing it into smaller pieces. The muscles also make waves pushing the food further down the digestive track. This is called peristalsis and happens from the esophagus all the way to the large intestine.

The stomach is lined with glands. These special cells make a liquid that is released into the stomach. This liquid is called gastric juice. The gastric juice has acid in it and helps break down or digest food.

The bottom part of the stomach is called the pyloric area. At the bottom of the stomach is another opening. This leads to the small intestine.

One of the most important parts of the stomach (and generally of the digestive system) is the bacterial fauna that populates it. Distinct to the specific environment, and part of a system that produces enzymes necessary to process some foods or optimize what can be extracted from what we ingest. A symbiotic (mutual beneficial) relation that is created and updated from birth, including the milk a baby gets from his mother.

What is the function of the stomach?
The stomach stores food and begins to digest it. It does this by using its muscles to crush food into smaller pieces. The stomach uses digestive enzymes and acids to break down food.

How does the stomach interact with other parts of the body?
The stomach does its job without you thinking about it. It is controlled by the nervous system. The nerves help tell you when to feel hungry. They also tell your stomach when to start making more chemicals for digestion.

The inner layer of the stomach has blood vessels in it. The blood supplies oxygen to the stomach so it can do its work.

Muscles in the stomach help move food through it. After the stomach has done its work, the food moves on to the small intestine.

How can you keep your stomach healthy?
Good digestion begins with chewing. Chewing food well and eating slowly is good for your stomach.

Eat when you're hungry. Don't eat too much or too little food. Try to eat food that doesn't have too much fat or sugar. Include vegetables and fruit in your diet. If you eat something that often makes your stomach hurt or feel bad, avoid that food.