Recent content by Jopi

Actually, the question came up in a statistical physics exercise, where we were asked to calculate the pressure of a photon gas confined to area A=L^2. And you need the number of polarization states when you change a sum to an integral. My theory is that the lecturer was lazy and just changed...

Hi, I stumbled upon this dilemma in a homework problem which involved 2D photon gas (unphysical, I know). How many polarization states are there for EM-radiation confined to 2D? In 3D it's 2, but how does it work in 2D? An EM-wave propagating in the z-direction can have its E-component...

Homework Statement As a part of a lab report, I need to calculate the distance of the (111) planes of an FCC lattice made out of spheres with diameter D. Homework Equations The Attempt at a Solution The course assistant has given me the value of \frac{\sqrt{6}}{3}D. I can...

I got the devices working now. The problem with the pressure gauge was that someone had changed the baudrate from the default value and that I had to first send an <ENQ> and the read. The cooler required an <STX> at the beginning of the message, and once I figured out how to send that it began...

I know the pressure gauge uses COM5 and the cooler is connected to COM6. If I click 'Connect' in the Test & Measurement toolbox I can connect to both ports, but Matlab cannot identify any devices. If I try to send a query to either device, I get no response before the timeout. The datatype for...

But I can control and get readings from the cooler with LabView, doesn't that imply that the cable is ok?

Thanks for your reply. I haven't built the setup myself, and I think I should not change it in any way. I know that at least the cooler works, I tried it using the old LabView software. The oscilloscope I have here uses a TCP/IP connection, so I can't try the serial port with that. I don't...

Hi, I have a cooler and a pressure gauge which I need to operate from Matlab. Both devices are connected to the computer via a serial port. I've been using the Matlab Instument Toolbox Test & Measurement tool to try and communicate with these machines. The problem is that I don't get any data...

Hi, this is not actually a homework question, but as it has mostly to do with computer science, I thought this would be the appropriate place. At work we have a measurement setup which is currently controlled by a LabView program. My task is to move the code from LabView to Matlab. I don't...

Homework Statement Prove that the number of electrons whose velocity's x-component is between [x,x+dx] is given by dN = \frac{4\pi V m^2 k_B T}{h^3} ln [exp(\frac{E_F -mv_x^2/2}{k_B T})+1]dv_x Homework Equations The Fermi-Dirac Distribution function: \frac{dn}{dE}=\frac{4\pi V...

Hi, I don't know if this is the right place, but I figured there'd be people here who know a thing or two about the said calculator model. My TI-86 is and old one (ca. 5 years). I didn't use it in the summer, and when I took it out again, there were multiple dead lines on the LCD screen. Is...