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Rajesh Prasad lectures on Materials Science
Добавлен 25 мар 2020
Видео
SymmetryScape: Patterns in Qutub Complex
Просмотров 4609 месяцев назад
Analysing patterns in Qutub Complex. This video is the continuation of ruclips.net/user/shorts2iVBf6WcLuI?feature=share I have been quite careless when writing plane group symbols in this video, P6mm and P4mm with capital P. Conventionally, for two-dimensional patterns they are written with small p: p6mm and p4mm. Capital P is reserved for space group symmetry in three dimensions.
How to squeeze in 25th. circle in the space for 24?
Просмотров 28210 месяцев назад
Comparison of packing of circles in square and hexagonal arrangements. This gives a mathematical explanation of the puzzle presented in the following video: ruclips.net/user/shortsTL0lZhIFKuE
Is HCP a Bravais Lattice?? | ChatGPT Crystallography Quiz Part 2
Просмотров 1,5 тыс.Год назад
Is HCP a Bravais Lattice?? | ChatGPT Crystallography Quiz Part 2
ChatGPT Crystallography Quiz 1: CsCl
Просмотров 1 тыс.Год назад
ChatGPT confused about whether the Bravais lattice of CsCl is BCC or SC
Volume of a unit cell in any crystal system
Просмотров 6 тыс.3 года назад
This video develops the formula for volume of a unit cell in the most general crystal system, triclinic System. The formula is derived using a result, established in another video, that volume is the square root of the determinant of the metric tensor.
Metric Tensor: Distances and angles in any crystal system
Просмотров 1,8 тыс.3 года назад
Metric tensor is a useful tool to calculate distances and angles in any crystal system. 00:00 Introduction 00:45 Dot product in Cartesian system 05:15 Dot product in crystal coordiante system 08:15 Metric Tensor 09:45 Metric tensor for Cartesian coordiante system 11:15 Metric tensor is symmetric 11:55Determinant of metric tensor is the square of the volume of the unit cell 18:20 Metric tensor i...
Stereographic projection V: Great circle through two poles
Просмотров 1,3 тыс.3 года назад
How to draw a great circle passing through two poles
Stereographic Projection IV Opposite of a Pole
Просмотров 1,3 тыс.3 года назад
This video describes the construction to find opposite of a pole in a stereographic projection.
Stereographic Projection III: Pole of a great circle
Просмотров 3,1 тыс.3 года назад
How to locate a pole of a great circle in a stereographic projection. At 9.30 and afterwards when I say 'reference circle' I mean 'reference sphere'.
Stereographic projections II Small circles
Просмотров 4 тыс.3 года назад
This describes how to draw and interpret small circles in stereographic projections
Stereographic projection I : Introduction
Просмотров 16 тыс.3 года назад
Introduction to stereographic projection
Ewald's sphere and electron diffraction pattern
Просмотров 10 тыс.3 года назад
Ewald's sphere and electron diffraction pattern
Primitive unit cell of an FCC lattice
Просмотров 31 тыс.3 года назад
Primitive unit cell of an FCC lattice
Primitive Unit Cell of a BCC Lattice
Просмотров 26 тыс.3 года назад
Primitive Unit Cell of a BCC Lattice
Reciprocal Lattice of a Simple Cubic Lattice Edited
Просмотров 8 тыс.3 года назад
Reciprocal Lattice of a Simple Cubic Lattice Edited
Proof of Weiss zone Law Using Reciprocal Lattice
Просмотров 1,7 тыс.3 года назад
Proof of Weiss zone Law Using Reciprocal Lattice
Crystallography Lec 7: Crystal = Lattice + Motif
Просмотров 2,3 тыс.3 года назад
Crystallography Lec 7: Crystal = Lattice Motif
Crystallography Lec 6: 7 crystal system and 14 Bravais Lattices on the basis of symmetry
Просмотров 4,5 тыс.3 года назад
Crystallography Lec 6: 7 crystal system and 14 Bravais Lattices on the basis of symmetry
Crystallography- Lecture 5: Basis for classification of Lattices
Просмотров 2,2 тыс.3 года назад
Crystallography- Lecture 5: Basis for classification of Lattices
Experiments done at B.Tech Intro at IIT Delhi 🧐
Просмотров 8 тыс.3 года назад
Experiments done at B.Tech Intro at IIT Delhi 🧐
Crystallography L4: Lattice Parameter as Basis for Classification
Просмотров 1,7 тыс.4 года назад
Crystallography L4: Lattice Parameter as Basis for Classification
Crystallography- Lecture 3: Missing Lattices
Просмотров 5 тыс.4 года назад
Crystallography- Lecture 3: Missing Lattices
NICE
Extremely happy with this. Thankyou so much. I have been searching this for soo long
awesome lecture
Really easy explanation....🙏
Why do we just take a section and say that it's the diffraction pattern? Don't we have to construct an Ewald's sphere and then find kd for the direction of the diffracted beam? Can someone please help?
Sir please also make a video on unit cell of a structure with ball to visualize
My professors are so bad at explaining... They always skip the explanation... But you sir... Bravo... You make even a plebian like me understand perfectly!!
He made materials science easier. Thnk u professor
Nice :)
just fantastic, Ewald sphere remained elusive in my physics course, until now that you explained it in a couple of minutes! But I think there is 1 mistake: the length of G*hkl vector should be 2pi/dhkl instead of just 1/dhkl, in order for the scattering condition G*T = 2 pi m, where m is integer and T is lattice vector, to hold. Correspondingly the length of CO or any other of those scattering vectors has to be 2 pi / lambda instead of just 1/lambda
Actually there are two different conventions which are used. I am using he convention most commonly used in crystallography text. Here the reciprocal lattice vectors and the wave vectors are defined without the factor 2 Pi. Thus reciprocal basis vector a*=bXc/V, b*=cXa/V, c*=aXb/V and k=1/lambda. Correspondingly, G*_hkl = 1/d_hkl. The other convention is used most commonly in physics texts where the factor 2 Pi is introduced in the reciprocal lattice vectors and the wave vectors. Thus a*= 2 Pi bXc/V, b*= 2 Pi cXa/V, c*= 2 Pi aXb/V and k=2 Pi/lambda. Correspondingly G*_hkl = 2 Pi/d_hk. So physicist's reciprocal lattice vectors, wave vectors and the radius of Ewald sphere are all linearly expanded by 2 Pi in comparison to the corresponding quantities of the crystallographer. However, if a crystallographers reciprocal lattice vector lies on the his/her Ewald sphere then a physicist's reciprocal lattice vector will also lie on his/her Ewald sphere. Thus both will agree whether in a given experimental setting diffraction happens or not.
@@rajeshprasadlectures okkay, good
excellent video!
Keep up the good work Sir We need more academicians like you
3:07 Sir, is there a typo for a2*=a1xa3/Vp? The cross product calculated I get in this way is the opposite number of a2*. Should it be a2*=a3xa1/Vp?
Yes, I made a typo here. You are right. Thanks for pointing this out.
Very very good explanation.
A complete assignment could be created around each monument! What a way to learn! Professor you are awesome!
Can anyone tell how this type of simple videos can be made ?
For this one I have just used powerpoint.
when you want study materials go to prof prasad
determine the angle between the primitive vectors in bcc structure
Since the primitive vectors of a BCC are along the body diagonal of a cube, these angles can be easily calculated as cos^-1 (-1/3) =109.5 Degrees.
materials engineering by prof.rajesh prasad is amazing
Sir in what special case we can make bct unit cell as fcc ?
BCT with c/a = Sqrt [2] will actually be an FCC. This is another example of why crystal systems should not be defined simply by their lattice parameters. So, to avoid this case you will have to say that for tetragonal system is one with a=b.NE.c as well as for BCT c.NE. Sqrt [2]. This sort of conditions will soon make definitions based on lattice parameters very messy.
@@rajeshprasadlectures thank you sir
if you need to understand materials go to prof .rajesh prasad
Dear Professor, I have a simple question: The Kroneker's delta is defined based on the cubic system? I don't get 1 from dot product of the vector a and the vector a* in parallelopiped and in any other lattice systrm not having the angle of 90 degree between the basis vectors in real space.
Kronecker's delta is just another name for the unit matrix. In the unit matrix only the diagonal terms are unity and all off-diagonal terms are zero. Similarly for kronecker's delta delta_11=delta_22=delta_33=1 and delta_12=delta_21=delta_13=delta_31=delta_23=delta_32=0. Thus ai. a*j=delta_ij is just a short way of writing nine dot products a1.a*1=1; a1.a*2=0; a1.a*3=0; a2.a*1=0; a2.a*2=1; a2.a*3=0; a3.a*1=0; a3.a*2=1; a3.a*3=1; The above relations are true for all systems and not only for cubic system. Note that we are not requiring a1.a2=0 which is true for orthogonal system (cubic, tetragonal and orthorhombic) but not for a general parallelopiped. We are requiring a1.a*2=0 where a*2 is a basis vector of reciprocal lattice and is not the same as a2. So by the relation a1.a*2=0 we are requiring that the second basis vector (a*2) of the reciprocal basis is orthogonal to the first basis vector (a1) of the real lattice. Hope this clarifies.
Brilliant! You an excellent teacher! Congratulations!!
thankyou you saved my life
Thanks for your time and effort for making such wonderful videos for young and old minds. We can only request you to keep doing more such videos.
You handwriting is beautiful 😍
Fantastic explanation, very clarifying. Thank you!
Bite me ... literally can't understand anything
Sorry indeed. I fail.
Thank you Sir for this interesting video
I dont comment very often, but damn. This channel is an absolute gem! Neither books nor lectures, nor other videos have explained matters this clear
Shouldn't the product of ai* and aj vectors be delta(ij) times 2pi?
This is purely a question of convention. The convention used by me is preferred by crystallographers where ai*aj=delta_ij. The convention often used by physicists is ai*aj*=2pi delta_ij. One can use either convention.
@@rajeshprasadlectures thank you a lot, now everything is clear
Thank you sir.
Thank you
sir your lectures are so great. In india this is the best course ever on material science . once I want to meet you sir. Sir if possible I am eager to do some internship/project with you sir . Now it has become dream to meet you Rajesh sir. Love from students community teachers like are the best ❤.
only if our professor could have been like you :/
amazing
Awesome🤩
Nice explanation
Interesting...
hi sir
Hello dear Sir, I really loved your introductory lecture on Material Science Branch at IITD, I'm really certain that I would Choose material science only its so interesting !! I have my JEE Advanced in a few months, I will work really hard to be able to meet you in person. please bless me, I'll be there soon. Dhanyawaad 🙏
Very much looking forward to this
Very interesting
sir please continue this series
exceptional and unique way of teaching ❤❤
sir , I have seen some videos where 32 crystallographic point groups are mentioned, but in this video you have explained 7 point group symmetries .what are the differences between these two?
Crystals (lattice+motif) can have 32 point groups. Lattice alone can have only 7 point groups.
Sir truly speaking I am a big fan of yours. Without you I could not have learnt crystallography so well. These lectures silently helping students. For your information I asked the same question to chat GPT. And it says,yes hcp is a Bravais lattice😂 So we should not believe chat GPT😂
thanks sir, so useful and convenient
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