The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction over the areas of broadband access, fair competition, radio frequency use, media responsibility, public safety, and homeland security.The FCC was formed by the Communications Act of 1934 to replace the radio regulation functions of the Federal Radio Commission. The FCC took over wire communication regulation from the Interstate Commerce Commission. The FCC's mandated jurisdiction covers the 50 states, the District of Columbia, and the territories of the United States. The FCC also provides varied degrees of cooperation, oversight, and leadership for similar communications bodies in other countries of North America. The FCC is funded entirely by regulatory fees. It has an estimated fiscal-2016 budget of US $388 million. It has 1,454 federal employees as of July 2019.
I have a problem with finding the energy of an electron in an FCC lattice using the weak potential method. We did that for a one-dimensional lattice during class, and I know that there was a double degeneration at the boundaries of the first Brillouin Zone. However, I'm not sure what...
https://www.researchgate.net/figure/1-Silicon-crystallographic-structure-It-has-the-diamond-structure-which-is-two-fcc_fig4_34172659 the fcc silicon lattice is shown.
My question is:
Since the silicon atom has 4 valence electrons and requires 4 more to be completed, why are so many atoms shown...
I have been developing some simple electronic devices to help with Animated Christmas Light displays. I was about to start selling professional versions of my devices, until I found out I am required to get them FCC certified. This costs about $2500 per design, which is completely outrageous...
My issue is more with the steps to approach rather than the calculations. I was just wondering if someone could confirm my approach to be correct.
As it asking for the reciprocal lattice of an FCC I assume this would mean I need to use the points on the BCC to calculate the geometrical...
Greetings,
for a Monte Carlo simulation of N hard spheres, I want to set up the initial configuration as a fcc lattice. I am thinking about how to do it most efficiently.
Here is the lattice structure:
The 3 lattice vectors, each one pointing to a different type of the 12 nearest neighbors...
Homework Statement
Three close-packed planes of atoms are stacked to form fcc lattice. The stacking sequence of the three planes can be altered to form the hexagonal close packed structure by sliding the third plane by the vector r over the second. If the planes in the fcc structure are all...
I tried to treat FCC lattice with a lattice constant a, as a monoatomic lattice.
The reciprocal lattice is a BCC with a lattice constant 2pi/a.
And the structure factor is 1.
But I can treat FCC lattice with a lattice constant a, as a simple cubic lattice,
with 4 atoms in each unit cell. As one...
Homework Statement
Based on sizes for Na(.97 Angstroms), Cs(1.67 Angstroms), and Cl(1.81 Angstroms), which lattice type would you expect for NaCl and CsCl and why?
Homework Equations
My equation for the hole size for a bcc is (4/sqrt(3))(radius)-2(radius), I assume you put in the radius of Cl...
What are the reasons behind the different microstructures of steel at different temperatures? I don't understand why steel at high temperatures (austenite phase) would favor an FCC crystal structure while steel at lower temperature (ferrite) would favor a BCC crystal structure.
The FCC's propagation models for the FM broadcast band seem grotesquely inaccurate in some places, where stations can be received that the models say are absolutely out of range. I'm not even talking about DX conditions like ducting or skip, I'm talking about baseline. When I lived in...
Homework Statement
I need to calculate the energy dispersion relation in the tight binding for simple cubic, base centered cubic and face centered cubic crystals. There are no values given, they just need the result depending on the lattice constant a.
Homework Equations
E (k) = alpha + beta *...
Taken from http://dao.mit.edu/8.231/BZandRL.pdf
BCC
In real space, it has a simple cubic lattice with one basis in the centre. Total number of atoms per unit cell = 2. Volume of primitive unit cell is then ##\frac{1}{2}a^3##.
In reciprocal space, BCC becomes an FCC structure. It has a simple...
Homework Statement
[/B]
(a) Show Compression of FCC leads to BCC.
(b) State rules for X-rays reflection in FCC.
(c) What are the new Miller Indices after compression?
Homework EquationsThe Attempt at a Solution
Part(a)[/B]
I'm quite confused as to what they mean by 'principal axes'.
For an...
Hi all,
Without first delving too deeply into the literature I wanted to ask if its is only permissible for FCC structures to have a coordination number of 12. In the case of lattice vacancies and/or distortion: wherein the atomic sites are slightly displaced; is there a kind of tolerence for...
The bulk modulus B = - V (∂P/∂V). At constant temperature the pressure is given by P= -∂U/∂V, where U is the total energy. We can write B in terms of the energy per particle u = U/N and volume per particle
v = V/N :
B = v...
I'm very surprised that nobody has posted on the topic. The FCC is planing to kill net neutrality in everything but name; as a result, the internet could change in very fundamental ways.
https://www.eff.org/issues/net-neutrality
It is already affecting investments in startups...
Homework Statement
Solids consist of a crystalline lattice of atoms-a unit cell that has a certain configuration of atoms that is repeated over and over. The picture that I can't post here, shows a pyramidal structure of metal spheres. The base is 8 spheres by 8 spheres with a height of 8...
Homework Statement
A wavelength of 0.7107 Angstroms is used to analyse a polycrystalline sample with a known FCC lattice structure. The interplanar spacing of the first peak is 0.3 A. Calculate 2θ for the first 3 peaks on the XRD pattern. First 3 peaks occur at (111), (200) and (220)...
I was just wondering why is it that the strengthening effect of interstitial carbon is different in FCC and BCC iron alloys. I can't figure this one out on my own so I thought I'd come to the place where the smart people hang out.
Any opinions?
Hi friends . is there anybody here who can give me a fortran code for describing fcc lattice and give us the neighbours of each site and also which pay attention to periodic condition ?
thank you for your help my friends.
Hi all,
I'm trying to solve a problem in Ashcroft - Mermin "Solid State Physics", Chapter 10: The Tight-Binding Method, and need your help.
Homework Statement
In problem 2(c) it says:
For a face-centered Bravais lattice with only nearest-neighbor \gamma_{ij} appreciable, show that the...
Hello All,
I've been reading about XRD and found this picture online:
http://en.wikipedia.org/wiki/File:Aluminumpowderpattern.png
My question, which might be due to the lack of background as I'm an ECE guy, is why are the FCC lattice vectors depicted of Spirals whose minima lie on the...
I have been acquiring some nice molecular models of graphene, buckyballs, and things like the model below.
http://www.indigo.com/images/product/172.jpg
One thing I have not been able to find are crystal models with the different orientations like face-centered cubic, body-centered cubic...
When doing these coordination numbers, which atom do I consider? Am I supposed to use only one unit cell to determine the number? When counting the number of nearest neighbors, does it mean literally that only the number of atoms with the shortest distance can be counted, meaning you find the...
does anybody know the upper limit of the bcc and fcc metals like Fe, Cu, Ag? According to the fact that the planes with high (hkl) indices have small interplanar spacing d_hkl, the smallest spacing would be present. what is that? atomic diameter of a specifc metal?
The number of lattice point in FCC?
Hi, I am having a trouble to figure the number of lattie point in FCC structure out. My textbook said simple cubic has 1 lattice point, BCC has 2 points, and FCC has 4 points. However there is no further explanation or figures. I am a kind of understand...
number of atoms in FCC gold cube with only the radius given!
1)it is given that the radius of a gold atom sphere is 144.2 pm, gold is packed in an FCC manner
Give the ratio Ns/Nv as a function of L (gold cube side) and a parameter
of FCC latice, knowing that Ns is the number of surface...
Hello i need help in this question
it is given that the radius of a gold atom sphere is 144.2 pm, gold is
packed in an FCC manner
Give the ratio Ns/Nv as a function of L (gold cube side) and a parameter
of FCC latice, knowing that Ns is the number of surface atoms and Nv is
the...
http://www.csmonitor.com/Innovation/Horizons/2011/0923/Net-neutrality-rules-are-coming.-Here-s-why-they-matter" .
and
http://www.pcmag.com/article2/0,2817,2393442,00.asp"
and
and
If you are alseep under a rock, this is a wake up call...
Rhody... :frown:
I was wondering, does anyone have any images that show the difference between the radial distribution functions for hcp and fcc lattices? I would be useful for reference purposes.
This may be obvious but since the packing fraction for both hexagonal close packed and face centered cubic is the same (74% i believe) why is HCP more common in elemental compositions?
Homework Statement
The proof seems fairly straight forward, but after plugging in the primitive vectors to the equations for the reciprocal lattice vectors, I'm getting
2\pi\frac{\frac{a^2}{4}(x+y-z)}{\frac{a}{2}(y+z)\cdot(\frac{a^2}{4}(-x+y+z))}
One proof I checked said that the bottom...
How is the distance between any two layers in a FCC unit cell equal to a/√3, where a is the edge length? I think it should be a/2 because the distance of a face centered atom from any 4 edges surrounding it is a/2. Can someone explain it geometrically?
Unit Cell -- Linear Density -- BCC&FCC
Homework Statement
Calculate the linear density for the most densely packed directions in BCC and FCC. Note the difference in linear density. Note the difference in linear density.
Homework Equations
LD = #of atoms/length
The Attempt at a...
The problem said:
"Determine the magnitude of the Schmid factor for an FCC single crystal oriented with its [100] direction parallel to the loading axis. "
The Schmid factor is the
"cos(\phi)*cos(\lambda)"
term in the equation for resolved shear stress.
I know that the slip planes...
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...
In my Physics lab, I'm doing X-Ray diffraction and attempting to determine the crystal structure of some common salts. To do this, I first need to determine the Miller Indices for the crystal structures that I'm considering. I can then match the location of peaks in X-Ray data (we're using...
How do you determine a plane or a point on a crystal lattice when translated to a rhomboidal primitive cell.
For example, rhombohedral primitive cell for an FCC is defined as:
a_1 = 1/2 a*(x+y);
a_2=1/2*a(y+z);
a_3=1/2*a(z+x);
If we have a plane, for example the 111 plane on an FCC, how...
i study from some books that the properties of a materials depends on the structure of it, while the structure depends on how it being process..may i know what structure actually it means? i can't get its meaning..does it means the processing methods will influnce whether the materials will be...
Hey guys I've got a question and I am not sure how to go about answering it without looking up a table of characteristics of elements!
Niobium has an atomic radius of 0.1430nm and a density of 8.57g/cm^3. Determine wheather it has an FCC or BCC crystal structure?
Now i think you have to...
Homework Statement
Write down the number of nearest neighbours in a FCC structure, calculate the angle between the bonds and the packing fraction.
Homework Equations
Literally don't know where to start!
The Attempt at a Solution
Very confused at the moment. Tried to look up...
Hello,
FCC metals experience significant tension-compression asymmetry because of the comparatively limited number of slip systems that act under compression, compared to tension, right?
Thanks,
-scott