Mobility Definition and 40 Threads

This is a basic conundrum that has bothered me for years: if you or a species like you is "adapted" to Twice Gravity (or any other multiple of 9.8m/2 squared) and your life functions and capacities are near identical, How strong/fast are you? Compared to 1G? See, this is the issue of mass vs...

How a high mobility of particles over surface cause to aggregation, the professor in the class said that "high mobility causes to local equilibration and thus to a compact aggregation".. which I didn't understand..! What does he mean about local equilibration and how all connect to each other?!

Referencing: http://www.vlsiinterviewquestions.org/2012/07/21/inverted-temperature-dependence/ Mobility decreases in a MOSFET with increasing temperature However, referencing: https://www.quora.com/Why-does-resistivity-of-semiconductors-decrease-with-increase-in-temperature Resistivity...

Engineers Students Doctors ... i would like to discuss some ideas in my projects .. and also can you tell me how do I know what clients need and want? the first project is about a wheelchair i just added on it a rod when you push it it will create a circular motion to the wheel so he needs...

Metals are highly effective at screening electric fields. If we place two contacts reasonably far away from each other on a piece of metal and apply a voltage bias, the charge carriers in the section that is far enough from both the contacts should be unaffected by the electric field. Why then...

Homework Statement A metallic film has length L=10mm, width W=1mm and thickness t=1##\mu m##. The current is parallel to the long edge and has magnitude ##I=0.7A##. Longitudinal voltage is ##V=1V## and it doesn't change with magnetic field. The Hall (transverse) voltage ##V_H## increases at...

Homework Statement ABCD is a plane rectangular strip of conducting material of uniform thickness, with a steady current flowing uniformly from AD to BC. The potential difference between E and F, the mid-points respectively of AB and CD, is zero, but when a magnetic field is set up at right...

Hello. Electron mobility in plasma is μ = q/m⋅ν, where q, m and ν are charge and mass of electron and electron collisional frequency. (https://en.wikipedia.org/wiki/Electrical_mobility) And unit of the mobility is m2/V⋅S (https://en.wikipedia.org/wiki/Electron_mobility) According to the...

A slab made of unknown material is connected to a power supply as shown in the figure. There is a uniform magnetic field of 0.7 tesla pointing upward throughout this region (perpendicular to the horizontal slab). Two voltmeters are connected to the slab and read steady voltages as shown...

Hi, Lately, I've been trying to compare and understand conduction properties of metals and semiconductors. However, there are two question on my mind that I'm still trying to figure out. Maybe someone here might be able to provide some clues. 1. It is known that a linear increase of the...

I need to find the mobility of the pictured system I have labeled the 5 links with black numbers and the 6 joints with red letters for convenienceAttempt at a solution: I know the mobility equation is M = 3(N-1) – 2(J1) – J2 + R, where N = number of links, J1 is the number of 1 DoF Joints, J2...

Dear all We (Maor Rosenberg and my co Vered Waksman) are Materials Engineering students at Ben Gurion University. We are working on a project in the field of mobility equipment for people who are physically challenged (as elderly and temporary/permanently mobility challenged people). As we work...

Homework Statement In the circuit shown, two thick copper wires connect a 1.5 V battery to a Nichrome wire. Each copper wire has radius R = 0.009m and is L = 0.17m long. Copper has 8.4 \times 10^{28} mobile electrons/m^3 and an electron mobility of 4.4 \times 10^{-3}(m/s)/(V/m). The Nichrome...

Hi! According to this http://en.wikipedia.org/wiki/Electrical_mobility, the definition of electrical mobility ##\mu## is: ##\vec{v} = \mu \vec{E}##. But since electrical mobility is always positive, this means that the velocity is always parallel to the E-field regardless of charge. How can...

I have measured the conductivity of a 2D material. I want to use σ=N⋅e⋅μ to find the mobility μ=σ/(N⋅e). https://en.wikipedia.org/wiki/Electron_mobility#Relation_to_conductivity I have measured N using a spectroscopic/imaging technique to get a Surface Density with units [cm^-2]. Mobility...

I have been told when making transport measurements of graphene it is usually placed in a cryostat and cooled to ~ 4K. However I cannot find any sources that back this up and don't fully understand why it is done in the first place. My thoughts are that it is to measure the carrier mobility...

Hello PF, thanks for having me here. I am working in chemistry and we are building a atmospheric pressure drift tube ion mobility spectrometer. The drift tube consists of 20 stacked stainless steel electrodes insulated by PTFE spacers connected via a resistor chain (voltage divider) to produce...

Hello PF Let's say I have a device with three layers, A, B, and C, where layers A and C are the anode and cathode. I can measure the IV curves from that device easily. Now let's say I added a fourth layer, D, in between A and B. Layer D interacts with layer B such that it increases it's...

how the dispersion relation(i.e. E-k relation) affects carrier mobility in metals or semi-metals?

Homework Statement So in one of our practice problems it states that as we increase the doping concentrations, the result will be a decrease in mobility. However, I thought that when you increase doping concentrations, there will be a higher concentration of carriers available for...

Hello I have been thinking about an idea for quite a while. It uses piezoelectric materials to enhance the motions of a human wearer. If someone were to move their leg up, the piezoelectric material will convex and produce a voltage this voltage would be used to trigger a semiconductor that...

I am going to give a presentation on High Electron Mobility Transistors (the ones that use a 2 dimension electron or hole gas), and although I can find many detailed descriptions of the band structures and what causes the 2DEG's high mobility, I haven't found a clear description of the process...

suppose we have a substance that is hydrophobic/hydrophilic and also has some charge on it surface(negative or positive) disspersed in water. if we add some salt different kinds possible(NaCl NaNO3 NaSCN). What is the effect of hydrophobicity and surface charge on Electrophoretic mobility?

Hello, I would like to know what are the chances of a couple getting two permanent academic positions in the same place, since it seems so hard to get a tenure track position? Have you ever tried (and succeeded?) in finding a position in the same city as your wife/husband, and what do people...

is it true that the ionic mobility increases with the decrease of the ionic size?

The electrical conductivity of copper is 5.96 x 10^7 S/m; its atomic weight is 65.546 AMU; the charge on the electron is 1.06 x 10-19 coulombs; the density of copper is 8.92 g/cm^3. Assume there is one free electron per copper atom. Calculate the mobility in cm^2/volt-sec. This is a...

Hi there, i've got a question about the mobility of the electrons in semiconductors and metalls. in a semiconductor the mobilities are ~ 1000 cm²/Vs. In metals the mobilities are in the range of 50 cm²/Vs. what's the origin of that great difference?

Heres the question: A sample of pure silicon, which has four valence electrons is doped with gallium, which has three valence electrons, to give a concentration of 10^23 m^-3. a. Is the material n-type or p-type? b. If the electron mobility is 0.14 m^2/Vs and the hole mobility is 0.05...

Greetings, I'm trying to understand how protons might move through solid water ice. More specifically this concerns how deuterium/hydrogen ratios are used to date ice core samples drilled into glaciers. On one hand I am told that, once it is deposited from the atmosphere in the form of...

Eg) Silicon Material When we say about mobility of a semiconductor - we basically have to consider its properties etc. One of it is impurities. Here we have to consider its TOTAL Dopant Concentration?

I found following quite interesting as well surprising. I always thought US have greater social mobility. http://news.bbc.co.uk/2/hi/americas/8162616.stm

Problem: Calculate mobilities of electrons and holes (assuming equal) in grey tin, silicon and germanium. Calculate also the mobility that would be necessary for diamond to have an intrinsic conductivity of 10-12 S m-1 if the hole and electron mobilities were equal. Working: \sigma = Nc...

hi, holes are the absence of electrons in the lattice, right? then how come we say holes have a +ve charge? shouldn't it be zero? also, why is the mobility of electrons more than holes? thanks

why the mobility of electrons more than holes despite the fact that electrons have larger effective mass than holes.

I'm sure you've all heard over and over again that income inequality in the US has increased over the years. This often leads people to conclude that "the rich are getting richer and the poor are getting poorer" and that "income mobility and opportunity are gone (or at least decresing)."...

Did Samuel Stupp (Northwestern University) inject/use stem cells when he got the paralyzed mice to walk again or did he just use molecules with he capacity to self assemble into nanofibres once injected into the body? (to get the stem cells to help with the healing, or to do whatever it was that...

Hey all, I have a pretty straightforward question about electron mobility in metals. We are given the length of a copper wire, it's radius, the current flowing through it, voltage drop across it, and the proportion of free electrons to copper atoms. I've found the current density...

Seriously, what does it mean and why is it good?

Hi guys, Just a quick question. In my lecturers notes, he has mobility and degrees of freedom as different things. With a separate equation for each. However, when I went searching the net for some info because I couldn't understand the notes, I found it to be different. The sites I...

I am looking for some good links on this particular methodology. Anybody have any?