Recent content by a b

Here is the code you asked for, there is also a readme.txt file with some instructions and the executable file for windows. I hope it will be useful. I'm not 100% sure that the executable file can run on any Windows computer, anyway I think it has a good probability to run on any Windows XP...

Hello, I'm interested in neural network programming but I am a beginner. Recently I wrote an example in C++ that I found in a book. It was a feedforward 3 layers network that learns the examples with the backpropagation algorithm. The aim of the network was to learn to "throw a stone": I taught...

You are right: you said it quite clearly in the first post you wrote. I've realized just now. I'm sorry, but for some reason I don't know, I missed the point of your explanation the first time I read it..

I've just asked a university teacher and he gave me an answer that I think is very explanatory and clear. He said that, since there is a potential difference between the compartments, actually a charge do exist inside each compartment, but it is a so small amount that it can be ignored...

Ok thank you. So what you just said applies to both Nernst and Donnan equilibria?

That is the same i thought: if there is potential difference, the two compartments must be charged; but i read in many places that in a Donnan equilibrium the potential difference is given only by microscopic charge distribution, in a order of a Debye length, while the whole compartments are...

Hello, I've heard that when you are considering a Gibbs-Donnan equilibrium, that is if you have for example a situation like this: There are two compartments 1 and 2 divided by a membrane, and at the beginning you have: In compartment 1 a neutral solution of permeable ions H+ and Cl-; In...

Hello everybody, i previously posted a topic about an exercise on luminance that was (appropriately, I admit) moved in the homework section. But nobody has still answered me. But the reason for which I didn't understand that exercise was that I was not sure about what luminance actually is, so...

Hello everybody, this question is about an exercise but I post it here because it is not homework, it is an exercise that I've done to learn by myself. I hope it is ok. It is an exercise from Irodov book (exercise 5.12) The exercise says: A small spherical lamp, uniformly luminous with...

to BruceW: I was certainly wrong , but maybe you too, or maybe you were just using a notation that I don't know: if you define Poynting vector as \vec S= \frac{1}{\mu } \vec E \times \vec B then you have, for linear polarization, <S>= \frac{1}{2} \sqrt{\frac{\varepsilon }{\mu}}...

Hello everybody, I have some questions: I'm talking only about traveling waves, not standing waves. If a linear polarized electromagnetic wave has electric field amplitude E_0, i know that its intensity is given by I=(1/2) (E_0^2 ) /c that is the Poynting vector averaged over a...

Hello everybody, I've often read that if a light ray travels from a medium 1 to a medium 2 and the two media have the same impedance, there is no reflected light at all, only transmitted light. So i made some calculations assuming to have two media with two different refractive indexes but same...