Recent content by Chuck88

Dear all, I want to know the meaning of end-pinching in fluid mechanics. Can someone provide me with the information?

Sorry that I did not make it clear. I want to know the steps of the derivation for the correlation between the curvature and bending stiffness.

I want to know why the moment could be represented as the product of the bending stiffness and the curvature. I do not quite understand the function of the curvature in the formula. http://en.wikipedia.org/wiki/Curvature

Thanks for your reply. The capacitor C2 is actually a piezoelectric disk and I am going to use the ultrasonic wave generated by the piezoelectric device to atomize the water. The reaon I want to vary the frequency is that for different piezoelectric disk, the resonant frequency is different...

Dear All, I am designing the circuit for an atomizer. The problem I am facing now is I do not know the method to change the frequency of the voltage applied on the capacitor of my circuit. Can you provide me some information about the way to change the frequency of the voltage applied on...

Thanks for your reply. I have found one link which could is also quite useful. http://mathinsight.org/curl_gradient_zero

Thanks for your reply and from the materials you provided, I have known some of the knowledge I did not know before. Another question is that suppose I have alreadly got the value of a curl, which is not equal to zero, how can I prove reversely that the potential does not exist?

When I am studying the ratation of the fluid, I found one sentence: "The irrotational flow must have the velocity potential." Why? Can someone tell me the derivation of this equation?

The details are that I am wearing the shoes and standing on the ground. Suddenly, I saw a pair of bare wires in front of me. I feel quite excited. So I run forward and touch one of the wires. Immediately, I feel shocked.

I know that rubber is a type of good insulator of electricity. But the problem is that we will still get shocked when we are wearing the rubber shoes. How does that happen? The rubber shoes should cut off the electric connection between us and the ground?

Can you explain that in detail?

Thanks for your reply. But ##\phi## in the real part ##\cos(\mathbf{k} \cdot \mathbf{r} - \omega t + \phi)## could represent the phase of the wave. And ##A_{0}## could represent the amplitude of the wave. It seems like that if we neglect the imaginary part of the wave, the amplitude and phase...

The plane wave function sometimes could be represented as: U(\mathbf{r} ,t ) = A_{0} e^{i(\mathbf{k} \cdot \mathbf{r} - \omega t + \phi)} and we could separate the expression above into: U(\mathbf{r} ,t = \cos(\mathbf{k} \cdot \mathbf{r} - \omega t + \phi) + i \sin(\mathbf{k}...

When I am studying the Rayleigh-Taylor instability, I saw this equation: \frac{\partial \eta}{\partial t} + u' \frac{\partial \eta}{\partial x} = \omega ' (\eta) I do not quite understand the meaning of this equation. Can some one provide me with some instructions and information...

Thanks for your reply. But if I am going to use the royer oscillator, I have to buy a DC voltage supply. I do not have the DC voltage supply which could provide 12 VDC. And also to build the transformer is not very easy for me to do. Can I use some type of amplifier which could be got on market?