Recent content by chenrim

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    A Free energy density in liquid crystals

    Hi, For someone who's familiar with LC's: How to derive the expression for free energy density of an hybrid aligned LC cell? what should be the vector for the director? I already familiar with the cases of splay and bend cell but couldn't understand how to derive it to the case where the cell is...
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    MATLAB Numerical Integration with Matlab - Solve K33, K11 Integral

    Hi all, i need help solving the following integral using Matlab: * tetam is a parameter and the integration is by alpha. the answer should be function of tetam * K33, K11 are constantsThanks , Chen
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    Bandgap Engineering simulation

    Hi, im looking to simulate Bandgap diagram of an heterojunction of AlGaAs/ GaAs with metal schottky contacts. can anyone please recommend me of a program that can perform this task? i'll be glad to know. thanks
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    MATLAB Transforming Complex Exponential to Discrete Vector Form

    Yes it's somehow related I want to use the Wigner-Ville algorithm, so in order to do it i need to make my signal discrete . since it's a complex exponential i don't know how to represent this complex signal as a vector thanks, Chen
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    MATLAB Transforming Complex Exponential to Discrete Vector Form

    Hi, I want to transform a complex exponential with quadratic phase to discrete form, in other words to a vector form. can anyone help me with that? Thanks
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    Solve Fourier Optics Output with Fresnel Transform

    1. I have the following setting of free space than a lense and again free space i need to solve for the output field as in the figure attached. 3. i used the fresnel transform once and then multiplied the field with the exponential and then convolved all the field. still couldn't make it to the...
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    Understanding NPN BJT Transistor: Ic & Ib Ratios

    Hi i have have a small question regrading to a NPN BJT transistor. the DC current gain (beta) is the ratio between Ic/Ib where Ic and Ib are the collector and base currents respectively. Ib is the input current, that's alright , but, i don't get why Ic considered as the output? in NPN BJT...
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    Find Help w/ Taylor Series: (y+dy)^0.5

    Yes you right X also should be taken negative. i didnt understand the step between line 2 and 3 https://drive.google.com/file/d/0B4wgc0vIE7CCUmpXLXJ0TEtIeUU/view?usp=sharing
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    Find Help w/ Taylor Series: (y+dy)^0.5

    The thing is that i have an r.v (random variable) of the form Y=X^2 and by definition : fy(y)dy= P{y<Y<=y+dy} i can substitute Y with (X)^2 and then i take the square root from both sides and get : P{ sqrt(y)<X<= sqrt(y+dy) }} now i want to show the PDF of X by the definition so i want to...
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    Find Help w/ Taylor Series: (y+dy)^0.5

    help with the following taylor series: (y+dy)^0.5 Thanks
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    System of two second order ODE's

    It's working , Thank you very much :) appreciate your help !
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    System of two second order ODE's

    I tried your seggestion and it's still doesn't seem to work out for me.. is it working for you?
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    System of two second order ODE's

    Hi da_nang thanks for your answer. I think i didn't fully understand. In the Mirage function i set two inputs: the first one is the time interval for solving the problem. the second will be a vector of initial conditions. the line where " xprime=.." i must have mixed values of x(1) with x(2)...
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    System of two second order ODE's

    Hi , I have tried solving the following system of ODE's (eq1 attached) using Matlab. first i reduced it into a system of four 1st order ODE's (eq2 attached). thani tried to solve it using ode45() in the following manner: function xprime = Mirage(t,x); k=2; xprime=[x(1)...
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    Cartesian unit vectors expressed by Cylindrical unit vectors

    I tried to understand it by the geometry of it but that's a better way to understand it. Thanks
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