Dos Definition and 49 Threads

In the following pdf I tried to calculate the density of states of free electrons and phonons. First, I found the free electron DOS in 1D, it turns to be proportional to (energy)^(-1/2) and in 2D it is constant. However, I am not sure I found the DOS for phonons in the second part of the...

I just want to clear some confusion I am having with the Fermi-Dirac distribution & density of states (DOS) of a semiconductor, which are given by Say we have a piece of Silicon in equilibrium and its Fermi level lies 0.25 eV below the conduction band edge, i.e. Ec - EF = 0.25 eV. Let us say...

Usually one would expect through \sigma=ne^2 \tao/m and DOS~1/m to argue that \sigma ~ DOS around Fermi surface. This seems to be a quite fundamental argument and should be expected to hold most of the time. For a quality check, does anybody have experience on how often LDA gives consistent DOS...

The recent news about a denial-of-service attack (DOS) that came via the internet-of-things (IOT) https://www.cnet.com/how-to/ddos-iot-connected-devices-easily-hacked-internet-outage-webcam-dvr/ brings up the question: How are the boundaries between "the internet" and other forms digital...

Hi guys, I have a very particular question on the derivation of DOS. For a particle in an infinite box k=π/L. However, when deriving the density of states, all textbooks use k=2π/L Now you could argue that they account for spin degeneracy, but its not that! Because in the textbooks that...

Hello! I am trying to run Dos copy command butim a confused a little about using it to copy folders to multiple folders.My problem is to write a command that will copy all folders from a source that could be something like G:\ or H:\ i.e from USB drive.Can i use G and H both at a time? Thanks in...

Can you suggest books or any resource that will help understand DOS graph discussions in journal articles? I am reading DFT results. I try very hard to understand how their discussion is related to DOS graph presented, but I can't no matter how I reread it over and over again. :frown...

In the Green Function theory. The Spectrum Function can be related to DOS. However, in the nonzero T condition, we can also define Spectrum Function. In the other hand, in my conception, DOS is the independent quantity which is determined by the system. So, does it mean DOS is actually a...

Hello! Does anybody know how to calculate the DOS as a function of Neff and λ/Λ? Thanks.

Hello! I know how to calculate band structure and density of states of photonic crystal (example is pic.1) Does anybody know how to plot such DOS maps? The second picture is from the article about photonic crystal fibers by Rodrigo Amezcua.

I have calculated the band structure of an infinite photonic crystal structure by COMSOL. So, I have an array of meanings of K-vector and different values of frequency V. I need to calculate density of states (DOS). How can I calculate it? Thanks.

Hi, I'm trying to understand(implement) Wang-Landau's algorithm to calculate the DOS. There are zillions of seemingly identical descriptions on the net, which I thought are straightforward to type into a machine - but when reading the papers(codes) I don't get the main point, i.e. for me it...

In some quantum textbooks [1], the tunneling transmission formula depends only on the density of states of 2 regions (DOS) involved in tunneling. (T(E)=C×DOS1(E)×DOS2(E), where C is constant). However, in Landauer transmission formula (without tunneling) the transmission depends on both DOS and...

To calculate the DOS of a material, the electronic structure typically needs to be calculated first. This requires lots of expertise and the accuracy is questionable. I'm interested in seeing if there's some shortcut to get some general properties of the DOS: If I could arbitrarily deform...

When I was a (very lonely) child, I used to play endlessly with this predator-prey simulation game: http://www.leinweb.com/snackbar/wator/ (You may have trouble getting this applet to run based on java updates, other security settings and what not). There is more information about it here...

I have a question regarind how to calculate the DOS for ferromagnetic impurities in a dielectric We have samples with ferromagnetic rare-earth ions implanted in a dielectric material. The concentration known and is quite high but the ions are probably only interacting weakly (they are on...

Hi,everyone,there is an important formula of DOS as follows, D_{n}(E)=\frac{Ω}{(2\pi)^{3}}\int_{BZ}dk\delta[E-\epsilon_{n}(k)] (1) On the other hand, another formula of DOS is often mentioned as follows, D_{n}(E)=\frac{Ω}{(2\pi)^{3}}\int_{S}\frac{dS}{\nabla_{k}E(k)} (2)...

I have a report for complete about DOC operating system and their requirements t, but i haven't good source for collected details please help my my friend,

Hi guys! When I was about 6-7 years old (around 1993-1994), I used to play to some DOS games in my aunt's house. I've sucessfully recovered the names of some of them (like the sleepwalker) but I'm stuck at finding the name of one of them that I liked. All I remember is that at start we are on...

Hello, I would like to buy a PC which is faster then my Pentium I,II, but can work under Dos 6.22. I have been told that a 32-bit pentium IV motherboard and processor could not be run under dos, is that true? If it is, can you tell me the fastest processor I can possibly use? Thanks a lot

I'm trying to find out how to "properly" fourier-transform a velocity-auto-correlation function (VAC), for calculation of phonon density of states (DOS), from molecular dynamics simulation. The problem I'm running into is that my calculated DOS: a) doesn't fall of to zero as the frequency...

Hello! I have accomplished creating the USB boot able flash drive, That boots with DOS, I had thought this would be the perfect way to take control over the hard disk when my Operating system is corrupted.. But it's not. On the Dos windows drive c: is shown but I don't think that's my hard disk...

hello nice people, some guy was saying something that one can check his code in dos also. the instructor said yes. i didnt understand it. it will mean that you can test the code even without compiler. i didnt understand the whole story so i hope you can fill in the gaps. any ideas what they...

Hi 1: Is this possible to use two or more DOS commands in the same line. When I enter the command "TREE C:\" it displays all the folders (=directories) and sub-folders present there in the drive C. But I don't want to see the sub-folders displayed in the tree. I don't know the command for...

dos "TYPE" command problem Hi You can see in the video that I have text file "hello" in "C:\Documents and Settings\Administrator". But when I try to access it using the "TYPE" command it fails. Could you please explain the reason for this failure? The "type" command displays the contents...

Hi Please have a look on the video. Is there a way to undo a certain DOS command? In the video I entered the command "color 3d", is there a way to undo this command and revert to the previous color scheme? Please help me. Thanks. Video:

Hi If I write the command "cmd" I get a different version of Command Prompt from when I enter the command "command". More or less they're the same but start with different 'initial' command string. What's the difference between the two? Please help me. Thanks. Video:

FreeDOS (formerly Free-DOS and PD-DOS) is an operating system for IBM PC compatible computers. FreeDOS is made up of many different, separate programs that act as "packages" to the overall FreeDOS Project. As a member of the DOS family, it provides mainly disk access through its kernel, and...

Hello! I have a very simple question... Does anyone know if exists on the WWW a database where I can download the calculated density of states for the transition metals? I want data not just pictures! Thanks

DOS stands for Disk Operating System. Why is it named so? Does the 'system' drive 'disk', or the 'system' is operated using some 'disk'? I know I have it right but it could help you to understand what I'm trying to ask. Please let me know. Thanks.

Dear all, I found in many references the authors pointed out the eg and t2g band in the DOS graphics, and wrote in the text accordingly that it had eg symmetry (or t2g symmetry). How did they conclude that just from one Dos graphics (sometimes d projected)? Best regards

Homework Statement have band dispersion \epsilon = \epsilon_c + \frac{h^2 k_x^2}{2 m_x} + \frac{h^2 k_y^2}{2 m_y} + \frac{h^2 k_z^2}{2 m_z} Show density of states is g(\epsilon) = \frac{m^{3/2}}{\pi^2 h^2} \sqrt{2|\epsilon - \epsilon_c|} Homework Equations 2 \frac{d\vec{k}}{(2\pi)^3} =...

Hi all. Is there any place where I can check how to derive the DOS of bilayer graphene subject to an external field. I have got the Hamiltonian right and solved the eenrgies but then I am not sure how to obtain the DOS right.. Thanks

Hi In this paper, http://people.ccmr.cornell.edu/~jcdavis/publicationPDF/NaturePhys_3_865.pdf, page 2 figure 1c, there is a plot of the Fourier transformation of the local density of states for some energy E. There is a thing I don't quite understand: The LDOS is discrete, i.e. it depends on...

Just a quick question. I have tried searching, but Google is fairly useless for me. Do any of you know of free C or C++ compilers that can create programs for DOS but run on Windows (specifically, Vista)? I have an old DOS machine but don't want to have to write code on it. Instead, I want...

Hi all, Sorry for starting a new thread that is similar to another previous one but the question I'll ask is different in fact. Please consider the DOS of a metallic CNT given in this thread: https://www.physicsforums.com/showthread.php?t=351722 On the other hand, the DOS of 1-D...

DOS of metallic CNT Hi all, I am in doubt on a subject. The density of states function of a metallic CNT, is given as http://img196.imageshack.us/img196/5629/adszuci.jpg in the book "Introduction to Nanoelectronics" of Hanson. On the other hand, in the same book, it is said that...

does anyone remember DOS? what do I type to repeat the last thing I typed, instead of typing it all out again, if there is such a thing?

Hi When I go in Dos fullscreen mode, and press prtScrn, the output I get in Word is not an image. Whatever text was on the screen, appears as a text, and not in any image form. Also, no colours (which were present in the exe file which I ran in dos mode) appeared. Can't I get the same...

Does anybody know how Green's function can be used to calculate the charge density of state? Thanks Tanja

It was more of a game actually. I believe the name of it was Moon Shot, Moon Lander or something to that extent. The game was laid out fairly simple. The entire game was composed of a white blob in the center of the screen (Earth) along with another eraser-head sized blob orbiting around the...

Hey guys, I was wondering if any of you can help me with my problem. I have this really small DOS program (~40 kb) that I am running and it is based on Kramers' formula. Now the thing is when you generate a graph in this program there is a message in the bottom right-hand corner that says...

Dears Is any method to calculate the density of states of spherical (purely) quantum dot?

Does anyone have a link for the derivation of the density of states for 2D electrons in an out of plane magnetic field, which also details collision broadening leading to the oscillatory density of states?

:mad: i can't find any bacth file commands anyone know were to find some?

I am looking for Turbo Debugger DOS version. Maybe this is too old? I can't find a dowload link for this software.. Anyone know where can I get one? Borland website doesn't have it..

My friend came to me with a problem about his computer. He unknowingly had a pirated copy of XP pro 2000, and tried to update. Well needless to say, he cannot log on to windows now. He doesn't have anything on the computer worth keeping, so I am just going to give him another OS. Question is...

I don't know if there is a thread with help on DOS but I am trying to find out how to use the BACKUP and RESTORE commands properly as I have tried to use them and have failed on a number of tries. Thanks for any help in advanced. The Bob (2004 ©)

1. how do i turn on/off a port? in m using win xp 2. how do i see the connect been established with my pc using DOS? many thanks