دانلود گزارش کارورزی و کار آموزی

چکیده :

The geometries of eighteen 1,5-benzodiazepines including their oxo and thioxo derivatives have been calculated

and compared with experimental geometries determined by X-ray crystallography using as property

the methylene flip angle. Protonation of 3H-1,5-benzodiazepine lead to a planar quasi-aromatic

cation. For the non-planar structures we have calculated ring inversion barriers that are well correlated

with ten experimental values determined by Dynamic NMR allowing the establishment of an empirical

equation for predicting new values

چکیده : 

Thiocarbonyl ene reactions via CAS and CAC bond formation routes have been performed using DFT

method at B3LYP/6-31G**//B3LYP/6-31G* level, indicating that both routes undergo concerted mechanism.

The reactions with 10 substituents on enophile were further examined. It was found that substituent

affects the activation energy and regioselectivity. An electron withdrawing group lowers the

activation energy and prefers the CAS bond formation pathway, while the reaction with an electron

donating group prefers the CAC bond formation route with higher barrier. It is worth noting that a very

strong electron donating group is kinetically and thermodynamically unfavorable for the thiocarbonyl

ene reaction. The substitution effect was explained by the reactivity index and charge transfer. And

the charge difference on C1 and S in enophile controls the regioselectivity.

چکیده : 

A computational investigation of the catalytic activity of the water molecules in the OH initiated degradation

mechanism of chloronitromethane is presented. The effect of the water solvated environment is

shown to be so important that even single water molecules can act as catalysts in this radical–molecule

reaction, accelerating substantially the dissociation mechanism. The calculations that involve the single

coordination of one water molecule, show very clearly the significant lowering of the potential energy

surface and the considerable reduction of the activation energy for the H abstraction pathway that initiates

the decomposition process

چکیده : 

This paper computes the quantization of the moduli space of flat SO(3)-bundles over an oriented

surface with boundary, with prescribed holonomies around the boundary circles. The result agrees

with the generalized Verlinde formula conjectured by Fuchs and Schweigert.

چکیده : 

Walking down stairs is a challenging perceptual–motor activity, as indicated by the large number of documented falls on stairs each year. The present study suggests that descending stairs is also a challenging memorial activity. A total of 147 people were videotaped as they descended a staircase. When the walkers were in the middle of the stairs, they looked down every third step on average, but as they neared the bottom, they looked down with high probability on or around the fourth step. The trigger for the last look down, by hypothesis, was disappearance of the stairs from the lower visual field. A model is proposed in which mid-stair walking is controlled primarily on the basis of visual guidance, whereas end-stair walking is controlled primarily on the basis of memory.

• Walking down memory lane: Where walkers look as they descend stairs provides hints about how they control their walking behavior
• DAVID A. ROSENBAUM
• The American Journal of Psychology
• Vol. 122, No. 4 (Winter 2009) (pp. 425-430)
• Page Count: 6

چکیده :

Inthisnote,wepresentasimplecombinatorialfactor6algorithmforapproximatingtheminimumhittingsetofafamilyR={R1,...,Rn}ofaxis-parallelrectanglesintheplanesuchthatthereexistsanaxis-monotonecurveγthatintersectseachrectangleinthefamily.Thequalityofthehittingsetisshownbycomparingittothesizeofapacking(setofpairwisenon-intersectingrectangles)thatisconstructedalong,hence,wealsoobtainafactor6approximationforthemaximumpackingofR.Incaseswheretheaxis-monotonecurveγintersectsthesameside(e.g.thebottomside)ofeachrectangleinthefamilytheapproximationfactorforhittingsetandpackingis3.

چکیده : 

Estimating the load-bearing capacity of brick masonry walls is a fundamental aspect of the design or retrofitting

of this type of structures. This paper presents a new ANN-based proposal as an alternative to the

different existing methods. The proposal takes into account load eccentricity, wall slenderness ratio and

stiffness and masonry tensile strength, and is validated by a comparison with the Eurocode 6 and other

formulations as well as three other experimental studies. The proposal closely agrees with the experimental

results and is less conservative than Eurocode 6 and therefore more likely to provide the optimum

design for masonry walls

چکیده : 

The aim of this paper is to propose some diagnostic methods in double generalized linear

models (DGLMs) for large samples. A review of DGLMs is given, including the iterative process

for the estimation of the mean and precision coefficients as well as some asymptotic

results. Then, a variety of diagnostic tools, such as leverage measures and curvatures of local

influence under some usual perturbation schemes, the standardized deviance component,

and Pearson residuals, are proposed. The diagnostic plots are constructed for the mean and

precision models, and an illustrative example, in which the texture of four different forms

of light snacks is compared across time with the texture of a traditional one, is analyzed

under appropriate double gamma models. Some of the diagnostic procedures proposed in

the paper are applied to analyze the fitted selected model.