Structures Definition and 324 Threads

Hello, My question stems from a research project of mine involving taking the normal modes of clusters of molecules from a potential. I was curious of the interpretation that can be made of normal mode vectors at a non-equilibrium structure, i.e something following a MD trajectory beginning at...

Given a real vector space, I understand the significance of defining a complex structure. Now, if J is a complex structure on a real vector space, and we find an anti-commuting complex structure I, so that we have I, J, and K=IJ, what are some interesting properties that we have now on our...

I'm posting this question here because I recall a certain book as being an outstanding introducton to algebraic structures and therefore worth knowing about in 2012. The problem is that I borrowed it from a library in the early 1990s and I can't remember it's name! Here's what I remember...

Say we complex structure J on a space with even dimension. Is there a trick to finding another complex stucture I that anti-commutes with J? Moreover I'm that these be integrable complex structres. Any ideas?

Homework Statement Let (M,J) be an almost complex manifold and [.,.] be the commutator bracket on vector fields. Show that if the map v \mapsto [v,w] is complex linear then J is integrable. The Attempt at a Solution This question essentially just boils down to showing that the...

Hello! I have silly question on resonance, it's so silly, I couldn't find an answer: Lets say there is a O=CR-CH=CH2 bonding in a molecule, R = some other group. You can get (I have put the charges in brackets and Superposition (I think that's what its called): (1-)O-C=C-C(1+) (ignoring...

Suppose S is a family of L-structures where L is some collection of constant symbols, relation symbols, and function symbols. Does the coproduct of elements of S exist? If not, how does one prove it? If yes, how is the coproduct defined? Are the maps from elements of S to the coproduct all...

Here is some code: typedef struct ExpandedTime { int et_usec; int et_sec; int et_min; int et_hour; } ExpandedTime* localTime(ExpandedTime* etime); Apparently the ExpandedTime* localTime(ExpandedTime* etime) is a function called localTime() that takes a pointer to an...

Here is a glimpse of my current research. This is a kinetic simulation of electrostatic waves in a bump-on-tail plasma, with multiple resonances and some dissipation. Quasi-linear theory predicts a flattening of the velocity distribution over the range of resonant velocities of linearly unstable...

Drawing 2D Velocity Structures? Homework Statement I need some help in drawing structures such as velocity of the plane relative to the air, velocity of the plane relative to the ground, and velocity of the air relative to the ground. Please give me some tips on how to drawing these, thanks!

I'm trying to point to the data in struct ele709_record john_doe into the total_mark function. But it's not working, the value returned is not the same as in struct. #include <stdio.h> struct lab { double experiment1; double experiment2; double experiment3; }; struct theory{...

Hello. I am an EE student with two semester left. I can optionally take a course on Data Structures from the CS department this next semester but am unsure if the material is old school or is still relevant today. The course covers the following topics with programming assignments in C...

Hi, On a surface evanescent waves are created when total internal reflection occurs. However when this surface has periodic structures of appropriate periodicity (gratings, photonic crystals) the evanescent waves are "freed" from the surface and they propagate to the surrounding media. I am...

Hi, On a surface evanescent waves are created when total internal reflection occurs. However when this surface has periodic structures of appropriate periodicity (gratings, photonic crystals) the evanescent waves are "freed" from the surface and they propagate to the surrounding media. I am...

Anyone? Anything? Even if I'm making little smiley faces on graphite? I'd love to make something that's more complex using steel, even if I have to stitch it together atom by atom.

What are they, how are they visualized? Is it like how basic equations when plotted form a shape (e.g. circle) but much more complex? When I think of the those words, I think of some sort of weird/cool looking shape.

Homework Statement Prove that if gcd(a,b)=1 then N\ S(a,b) is a finite set. Homework Equations The Attempt at a Solution I'm new to set theory and this question is from a voluntary course that don't give any credit. I'm not sure how to start off here. What does the S(a,b)...

Hi All, I've written some code in Matlab that calculates a number of parameters and saves the data to a structure. A portion of the code is shown below: uniqueName = genvarname(date); plant(id).(uniqueName) = {date avgHeight avgVol}; . The various parameters such as avgHeight etc. are...

So we have the covalent Radii of Ga = 1.26 A and As = 1.19 A. And the structure is Zinc blende with arsenic occupying half of the tetrahedral sites. So its probably not close packed... The formula the works for me is, [4/sqrt(3)] x [ radius of Ga + radius of As ]. I can get the answer ( 5.66...

The problem has been highlighted in the attached picture, it's an old exam paper question and I've been trying to do it in preparation for a university exam. I am confident in modelling the structure (into both shear panels and edge members), and confident that I am able to identify both...

Structures (civ Eng) urgent help Hello, I've got two resit exams coming up in over a week for Civil engineering first year structures 1a and 1b. I've been attempting several past papers and there were some questions I desperately need help with. I'm not sure if this is exactly the...

Let Q be the group of rational numbers with respect to addition. We define a relation R on Q via aRb if and only if a − b is an even integer. Prove that this is an equivalence relation. I am very stumped with this and would welcome any help Thank you

What is data structures in C and C++ all about? I heard that data structures are useful in constructing menu items of any software's menu bar. Is it true? Please tell me more examples of the applications of data structures in real life. Thanks.

Homework Statement Using the method of sections, determine the force in members BD, CD, and CE of the roof truss shown in the figure (the red line is the cutting plane and the green arrows are my assumed directions of the unknown forces) Homework Equations summation of moments=0...

Which is better Java or C/C++ with data structures and why?

I always see them in my dynamics problem but I never understand what are they used for, typically? Just to get some sort of perspective on the thing. It's supposed to be a rod connected to two pistons moving with linear and circular motion...

hi! i have a bunch of questions where I'm suppose to indicate if a structure is statically determinate i have way to do this that usually gives me a decent answer. i go with r > 3n means it's indeterminate, and r = 3n means it's determinate. r represents reaction forces, and n represents...

QUESTION: " Political and legal systems are often labelled as either being 'democratic' or 'non-democratic'. Compare the structures of such systems. " HOW?: I look at this question and not know exactly what I am looking for. What exactly is a structure of democratic and non-democratic...

Every so often I return to the idea of structures as used in logic & clean up my ideas about them, here is my latest attempt, four questions based on the short summary below, would really appreciate any help from you guys. A structure is a triple of the form = (F, σ, I). F is a set of...

Hi everyone. I'm very interested in how order and structures arises in the universe, but I don't get how thermodynamics (which seem to be closely linked to order, especially the second law) relates to that... So I will ask a few questions. Please don't be too technical, I study computer...

Homework Statement Let A be the set of all strings of a's and b's of length 4. Define a relation R on A as follows. For all s,t \in A, sRt, s has the same first two characters as t. s=baaa t=abaa Homework Equations The Attempt at a Solution I just want to know if the order of the first two...

I have a question that is asking me to draw a diagram and explain the structure of different types of capacitors. I am actually not sure what they're referring to. Do you think they might be referring to types of capacitors like: Ceramic capacitor, mica capacitor, Electrolytic capacitor. The...

Homework Statement I have attached a jpeg of the question invloved. Involving finding shap factors for both the T and the sqaure piece. Homework Equations Due to illness i missed the lecture for this topic and as such i am missing the relevant equations on how to attempt this. If...

Homework Statement The following hydrocarbons have different structures but the same atoms except for one. Which of them is this exception and what is the difference? a)cyclobutane b)1-butene c)2-butene d)cyclobutene e)methylcyclopropane Homework Equations Which of them is this...

Homework Statement In the enclosed picture is a loaded beam and strut, what I need to do is determine the reactions at the supports. The problem is that I think the beam is indeterminable because there are more than three reactions? Homework Equations I do no the three equations of...

My teacher is explaining resonance structures in class, but I don't understand it that well. Can someone please help? (:

I just found out that the words "algebraic structure" have a precise definition and that this notion is not just common language! Then below this definition they give another (equivalent) definition: So based on this I have three questions: 1: How is this concept explained in terms of...

Structures of Glycine at pH's 1, 5.97 and 13, just wondering if anyone can confirm these, been a while since molecular bio. pH 1 pH 6 pH 13 Regards, Andrew Johnson

Hi guys, was wondering if someone could help me with a homework problem. The problem: The input is an N x N matrix of numbers that is already in memory. Each individual row is increasing from left to right. Each individual column is increasing from top to bottom. Give an O(N) worst-case...

I'm only talking about carbon-carbon double/triple bonds here. A nucleophilic atom is one that would donate electrons to an electrophile (often a highly electronegative atom like oxygen or a halogen). Anyways, what about carbon-carbon double bonds? I'm inclined to think that they're less...

I am writing a program in C (vanilla, non-C++/C#) and I am having trouble figuring out why my initialization of my array of structures isn't working. I have tried a number of things without any luck. I still get a compiler error: "conflicting types for 'cardInfo' " I am writing a simple...

I'm working my way through The Art of Writing Reasonable Organic Reaction Mechanisms by Robert B. Grossman (excellent book, by the way), but the way he describes resonance is confusing me. I feel like the more I think about it, the more confusing it gets. Consider a carbon-carbon double...

Homework Statement (Fraleigh's Algebra, 2003, p. 36) There are 16 possible binary structures on the set {a, b} of two elements. How many nonisomorphic (that is, structurally different) structures are there among these 16? Phrased more precisely in terms of the isomorphism equivalence...

Let J be a set of all linear functions. Consider the set R^2 in the Euclidean plane. Define a binary operation * on R^2 in such a way that the two binary structures <J, +> and <R^2, *> will be isomorphic. Any thoughts? If something is not clear please ask. Thank you.

i have to fill in the blanks for the following questions using the following choices (some will be used once, others more than once, and others not at all) : z-dna, cruciform structure, mirror repeat, hairpin structure, g-tetraplex, triplex dna, hoogsteen pairs, a-dna, duplex dna, inverted...

I was wondering if someone could tell me (in pedestrian terms) what are the crystal structures of aluminum, copper and iron as a function of the temperature. I just read the chapter on crystalline arrays of Callister's Materials Ecience & Eng. but the book just says that Cu and Al have a FCC...

When drawing a Lewis structure for a compound how do you know what bonds to what? For example, with H2SO4, how does one know whether the H bond to O or to S?

Hello I have used Data Abstraction and Problem solving in Java Walls and mirrors, for my 1st data structures course I found i didn't use it that much at all, it pretty wordy and quite boring to read. Can anyone recommend me a good book for data structures? Basically in the course we...

Homework Statement The maximum size to which a cell may grow is limited by the cell's ? Homework Equations NIL The Attempt at a Solution It's a multiple-choice question... so i picked nucleus. My argument is that the nucleus controls the internal functions of the cell. However...

Hello all, experts and otherwise. I'm looking for some links to software and documentation for selecting Regions of Interest (ROI) in MRI data of the human brain. Saving ROIs is a must. Any tips also appreciated. Thank you!