Structure Definition and 1000 Threads

  1. A

    A question about band structure silicene by tight binding

    Dear forum people, I know that electronic properties silicene is the same graphene but i can not figure out how can I plot band strcture silicene. I want to plot that in the following path: K→Γ→M→K
  2. P

    Regarding a bimorph's structure

    Can anyone explain to me why a bimorph has a metal in between the two piezo-layers?
  3. ZapperZ

    Impact of question structure on student's performance.

    This EJP paper is open access, so you should be able to read it. The conclusion isn't unexpected, because having a "scaffolding" to guide a student through a problem is almost like hand-holding without an instructor being there. I've used this type of questions during quizzes and maybe even...
  4. Y

    Hyperfine Structure of $^133Cs$: Find I & J

    Homework Statement A transition happens for ##\lambda = 494nm## in the Cesium ions (##^133 Cs##) between a term in the ##5p^5 6s## configuration and term in the ##5p^5 6p## configuration. Five components are observed with the following energies (relative to the transition of least energy): 0...
  5. ROYAL MADAN

    How to join honeycomb and skin in ansys apdl for sandwich structure

    I modeled honeycomb core and face sheet seperately now i want to add or glue them to make a sandwich but it shows error so how can i join them.anyone please
  6. Kitrak

    Solving Spinal Structure Mystery in Solid State Chemistry

    In solid state chemistry, what's a normal spinal structure? I came across a question about it and I couldn't find any credible answers.
  7. U

    How Is the Polyacetylene Chain Structured in a 1D Lattice Model?

    Homework Statement The polyacetylene chain is a 1D chain of Carbon atoms with single bonds and double bonds in succession. Spacing for single bond is ##a_s = 0.144~nm## and spacing for double bond is ##a_d = 0.136~nm##. Describe the structure using a "lattice" and a "basis". Sketch the...
  8. R

    What type of bonding is involved in the structure of DNA?

    I'm getting confused with the type of bonding (1) between the nucleotides and (2) between the nucleotide and the "sugar phosphate backbone". This diagram: http://tigger.uic.edu/classes/phys/phys461/phys450/ANJUM04/DNA_helix.jpg Shows hydrogen bonds between the nucleotide bases. But then Wiki...
  9. Raf76

    Guides for bolt diameter and length against plate thickness?

    Hi, I tried to find design regulations/codes that specify relations between bolt diameter/bolt length against connected plate thicknesses. I couldn't find that in Eurocodes 3. Can someone help me with info where to find those regulations ? Example: can we connect 5 mm plates using M24 ? or...
  10. R

    What if the packing parameter of a lipid structure is greate

    ...r than 1? This is the slide we have been given in class So what on Earth would the structure of PA, PC and PE be? I understand the closer to 1 it would be a bilayer so PC is likey a bilayer but can't understand what the others would be from this slide, does anyone have any ideas?
  11. T

    OneDrive for business - easy access to folder structure?

    I'm considering using OneDrive for business as a part of Office 365. What I'm unsure about is how to use it exactly. What I need it for is simply as a way of accessing my files and folders in the File Explorer. What I don't get is this sync-business I keep reading about. If the only thought...
  12. A

    The structure of carbon graphite

    hi everyone I found out that graphite carbon conduct just in one side if there is anyone who can inform me how is the structure of this material?
  13. T

    How Does the Universe Use Temperature Differences to Create Structures?

    The main result of thermodynamics is that if you have a place that is hot and another place that is colder, you can operate a heat engine by absorbing heat from the hot place and dumping it in the cold place, extracting some useful work in the process. It gives you a way to calculate the...
  14. B

    Plotting Band Structure in Graphene for Scientists

    I just learned how to get a tight-binding dispersion for graphene. But i can not figure out how can I plot that. I want to plot that in the following path: Γ→K→M→Γ I would be appreciated if could some one give me a hand on my problem. thanks for alot.
  15. AdityaDev

    Why Do 1s and 2s Orbitals Have Different Electron Probabilities?

    From the ψ2 vs r graph (i.e probability of finding an electron vs distance from nucleus graph), there are no nodes for 1s orbital while there is a node in the 2s orbital graph.But they have similar structures right? Then why is there a difference in finding the probability of finding an...
  16. D

    Problem about electronic structure

    Hello everyone! The electronic structure of CNT is discussed on the basis of band structure of graphene. Graphene has a linear dispersion relation: E = h_cut vF |k| where k is the 2D wavevector and vF is the Fermi velocity. CNTs are macroscopic along the axis but have a circumference of atomic...
  17. ugenetic

    Band Structure of a solid is not related to the size/doping?

    Look at the diagram below, after all that doping, 2 blocks of Si have the same band structure? My understanding of band structure and fermi level is that: Given a block of solid (Please note, not a TYPE of solid, but this PARTICULAR block of solid) it will have its own unique band structure...
  18. J

    Constructing a Bending Moment Function Using McCauley's Method

    I have A beam of 1.2 m long, supports at 0m and 0.8 m. forces of 10 N at 0.4 m and 5N at 1.2 m I need to find the deflection equation for this situation. Can someone have a look and see if they can come up with the equation. As I have tried but my results do not match what I am expecting
  19. Ahmad Kishki

    The Mathematical Structure of QM and the Stern Gerlach

    Many books in QM (eg: Sakurai) mention that the stern-gerlach experiment provides enough motivation for the mathematical structure of QM, Sakurai even mentions Gottfried's book. Point is, i didnt find Gottfried's book, so i am looking for other books that develop the math of quantum mechanics...
  20. eis3nheim

    What is the best referece book to study atomic structure?

    what is the best referece book to study atomic structure and electronic structure of atoms ?
  21. U

    How Is Shell Structure Evidenced in Atomic Nuclei?

    Homework Statement (a) What shows the existence of shell structure? What are the other numbers? (b) Deduce the spin and parities. Homework EquationsThe Attempt at a Solution The shell model is given by: So for Li, 3 protons pair up with 3 neutrons, leaving an unpaired neutron in...
  22. M

    Structure of generated sigma algbra

    I am think what is the structure of generated ##\sigma##-algebra. Let me make it specific. How to represent ##\sigma(\mathscr{A})##, where ##\mathscr{A}## is an algebra. Can I use the elements of ##\mathscr{A}## to represent the element in ##\sigma(\mathscr{A})##?
  23. H

    Independent calibration of structure and load cell?

    I have a load cell which must be placed onto a piece of vehicle structure. In an ideal world I would attach the load cell to the structure and calibrate both together to ensure a very accurate calibration, and that accurate loads are measured. However a problem arises if I need to replace the...
  24. nate crosby

    Free Body Diagram -- forces on a structure over a balcony wall

    Hi, I am trying to work out the forces involved at the contact points in a design of a structure over a balcony wall. I have drawn up the cross section of the situation equilibrium, with a tolerance. I want to find out what forces will be acting on the structure and the balcony wall when a...
  25. R

    Determine Crystal structure of non-cubic crystal in XRD plot

    Given only 2theta and intensity, how to know the crystal structure (except cubic) of non cubic crystals, and also determine their lattice parametera,b,and c, if there's a link or website discussing techniques to determine crystal structure of all crystals, please don't hesitate to put it here...
  26. N

    What is the format for ionic lewis structure w/ resonance?

    Homework Statement I need to draw NH4NO2 which is an ionic compound. 3. The Attempt at a Solution NH4 is fairly straightforward to draw, with one N in the middle and four H surrounding, and no lone pairs. The problem comes with NO2- which is one nitrogen bonded to two oxygens. However, one...
  27. Robsta

    Why Does the Matrix Element <2 0 0|z|2 1 0> Equal -3a0 in Hydrogen?

    Homework Statement Show that for hydrogen the matrix element <2 0 0|z|2 1 0> = -3a0 where a0 is the Bohr Radius. On account of the non-zero value of this matrix element, when an electric field is applied to a hydrogen atom in its first excited state, the atom's energy is linear in the field...
  28. Saint.V8

    How Do I Calculate Floor Loading for My Structure?

    Been trying to bend my head round something that is no doubt so simple it is unreal...! I am designing a structure that has a total weight of 1.6 tonnes (1600kg), the structure floor area is 8m x 3.5m and sits on 8 pads of 500mm x 500mm. To calculate the floor loading do I: Divide the weight...
  29. A

    Determine the structure function

    hi how can I determine structure function ## F_2## in ##R=QCD##, with having ##F_2## in ##R=0## in special ##x## and ##Q## ? thanks
  30. J

    Aluminum structure modifications for use near a very hot fire

    I'm building an frame out of solid 5/8 inch thick aluminum square bars. this frame will be around a fire temps close to melting points but there will be insulation in make sure it won't melt. I was thinking about drilling holes in the free space of the aluminum to reduce it's weight and if you...
  31. C

    Simple Statics Question: Truss Structure

    Homework Statement Homework Equations ∑M = 0, ∑Fx = 0, ∑FY = 0 The Attempt at a Solution If so, If so, I will be using the method of sections to cut along the red line as indicated in the picture. This gives me 3 equations of equilibrium as shown above. However, before solving these...
  32. Oxymoron

    Metrics and Group Structure Reduction

    I don't understand the geometry of what happens when you give a manifold a metric, in particular how the group structure reduces to the orthogonal group. I've read the wikipedia article http://en.wikipedia.org/wiki/Reduction_of_the_structure_group a dozen times but I get stuck when it says that...
  33. S

    Gold Atom Count in O-Ring: 10.4x10^21

    Homework Statement A golf O-ring is used to form a gastight seal in a high-vacuum chamber. The ring is formed from a 100-mm length of 1.5-mm-diameter wire. Calculate the number of gold atoms in the O-ring. Homework Equations Volume of cylinder = PI*h*r^2 The Attempt at a Solution I got the...
  34. S

    Books on Atomic Structure, Chemical Bonding, Quantum for Beginners

    Hi all! I would like to ask your help! I am a rookie in the subject. I have to admit i don't exactly interested in the mathematical way. I really don't have the "basic" advanced math which would needed it. :) Look at me if i would be a high school physics and chemistry teacher whose imaginary...
  35. L

    Structure of orbits at a tornado, whrilwind, etc.

    Any sites showing the whole structure of direct orbits of air molecules inside and outside of any type of turbine? By "direct" orbits, I mean between the two successive clashes of each molecule with other molecules.
  36. I

    Compute subband structure of graphene

    There’re 2 ways to calculate the subband structure of graphene nanoribbon using tight-binding model, for Zigzag chain: The first one is to diagonize the Hamiltonian $H = H_0 + H_10*exp(i*k_x) + H_01*exp(-i*k_x)$ and obtains the eigenvalues. The second method is just diagonize the Hamiltonian in...
  37. Paul Shredder

    Structure of a Matrix With Empty Null Space

    Hi guys, I hope you are having a great day, this is Paul and, as you have seen in the title, that's what I'm looking for, let me explain: When you have a square matrix with empty null space, that is, the only solution to the equation Ax=0 (with dim(A)=n x n) is the vector x=0n x 1, means that...
  38. J

    Inner product structure for classical diff equations

    I'm interested in what people know about the application of inner product structures (usually reserved for QM) to diff equations describing classical physics, in particular non- hermitician diff operator of the Fokker-Plank equation. Thanks.
  39. H

    Why is CNT considered a 1D structure despite having movement in two dimensions?

    The electronic structure of CNT is discussed on the basis of band structure of graphene. Graphene has a linear dispersion relation: E = h_cut vF |k| where k is the 2D wavevector and vF is the Fermi velocity. CNTs are macroscopic along the axis but have a circumference of atomic dimensions, which...
  40. R

    Derive Primitive Vectors in Complex Crystal Structure

    Hi Guys, please help me. how can i derive the primitive vector of copper oxide (I)? basically this is cuprous oxide having a cubic crystal structure but since it has oxygen in it the directions and magnitude of primitive vector are far different compare to basic cubic structure. also please help...
  41. L

    What Would Happen to Humanoid Bone Structure If the Moon Crashed Into Earth?

    Hi all, This is a bit of a bizarre question, but: If some way, some how, the moon crashed into Earth... then (oh so many) years later humanoid life appeared, what might its bone structure be like in contrast to ours? That is all
  42. L

    Does glucose in its cyclic structure react with HI ?

    does glucose in its cyclic structure react with HI to form CH3-CH2-CH2-CH2-CH2-CH3? (open chain structure of glucose reacts with HI to form CH3-CH2-CH2-CH2-CH2-CH3)
  43. G

    S-matrix structure of the lightest particle

    If you have a particle that is the lightest particle, then it cannot decay into other particles. As a consequence of this, its T-matrix amplitude on-shell should be zero, since the S-matrix is S=1+iT, and the amplitude for the particle to be found with the same quantum numbers and momentum is 1...
  44. LokiReise

    A question about a rotating space structure

    So I was thinking to myself, if i had a somewhat disproportionate tripodal space structure, how would i make it rotate around a chosen point where the arms of the structure (hallways and passes most likely) converged ? TORQUE AND MOMENT OF INERTIA ! Then I thought about something else...
  45. T

    Optics - Obtaining structure of an object using a laser

    Hi, Recently I did an experiment to try and discover what some objects look like microscopically, using a laser and looking at their diffraction patterns. We used the fact that the intensity profile you obtain is the Fourier transform of the object you're shining it through, so we can recover...
  46. M

    Formation of Excimer Structures: Explained for Engineers

    Reposting from another section... Can anyone explain to me how an excimer is formed? Like structure wise? Considering Xenon. I've gathered that an excited state Xe*, ground state Xe, and a 3rd body M react resulting in an Xe* excimer + M(carrying away excess energy). I'm struggling to find...
  47. TrickyDicky

    Fine structure constant meaning

    I admit that I have always seen this number as a simple proportionality constant relating other constants and units. But there is a long tradition attributing it all kinds of deep physical and even mystic significance, what do you think?
  48. G

    Calculating Stiffness & Displacement of Structure w/100kN Weight

    Homework Statement 1. A structure with weight of 100 kN and which has a natural period of 1 second. Compute the stiffness of the structure. The structure has 5% critical damping. The structure when at rest is subjected to a half sine wave loading having a magnitude of 10kN and lasting 2...
  49. R

    Primitive vector of complex ceramics structure

    Hi Guys, please help me. how can i derive the primitive vector of copper oxide (I)? basically this is cuprous oxide having a cubic crystal structure but since it has oxygen in it the directions and magnitude of primitive vector are far different compare to basic cubic structure. also please help...
  50. T

    Chemistry Molecular Structure: Thorium & Rubidium; Thorium & Phosphour

    Homework Statement Got a homework question for what kind of molecular structure you would get by combining these to metals: Thorium and rubidium, thorium and phosphour. Got to draw the Lewis diagrams and VSEPR model for these molecular structures, and predict the geometry - bond angles - bond...
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