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11.
12.
The energy and structural changes of lithium microclusters based on temperature has been investigated by using Molecular-Dynamic simulation Method. Two and three-body interacted semi-empiric potential energy formula that characterized the interaction has been used. It has been calculated that the dissociation of atoms from cluster has started after 1300 K for Li3 and 1350 K for Li4, respectively. Dissociations at the fixed temperatures are very close to the expected values of the lithium metal. Additionally, it has been observed that Li4 microclusters above 1000 K and Li3 clusters above 700 K temperatures have steady structures in two different energy values. 相似文献
13.
Parabolic trough collectors generate thermal energy from solar energy. Especially, they are very convenient for applications in high temperature solar power systems. To determine the design parameters, parabolic trough collectors must be analysed with optical analysis. In addition, thermodynamics (energy and exergy) analysis in the development of an energy efficient system must be achieved. Solar radiation passes through Earth's atmosphere until it reaches on Earth's surface and is focused from the parabolic trough collector to the tube receiver with a transparent insulated envelope. A11 of them constitute a complex mechanism. We investigate the geometry of parabolic trough reflector and characteristics of solar radiation to the reflecting surface through Earth's atmosphere, and calculate the collecting totM energy in the receiver. The parabolic trough collector, of which design parameters are given, is analysed in regard to the energy and exergy analysis considering the meteorological specification in May, June, July and August in 1sparta/TUrkey, and the results are presented. 相似文献
14.
Summary The paper presents a thermodynamically consistent constitutive model for elasto-plastic analysis of orthotropic materials at large strain. The elastic and plastic anisotropies are assumed to be persistent in the material but the anisotropy axes can undergo a rigid rotation due to large plastic deformations. The orthotropic yield function is formulated in terms of the generally nonsymmetric Mandel stress tensor such that its skew-symmetric part is additionally taken into account. Special attention is focused on the convexity of the yield surface resulting in the nine-dimensional stress space. Of particular interest are new convexity conditions which do not appear in the classical theory of anisotropic plasticity. They impose additional constraints on the material constants governing the plastic spin. The role of the plastic spin is further studied in simple shear accompanied by large elastic and large plastic deformations. If the plastic spin is neglected, the shear stress response is characterized by oscillations with an amplitude strictly dependent on the degree of the plastic anisotropy.accepted for publication 2 March 2004 相似文献
15.
We study nonlinear resonance in viscous gravity-driven films flowing over undulated substrates. Numerical solution of the full, steady Navier–Stokes equations is used to follow the emergence of the first few free-surface harmonics with increasing wall amplitude, and to study their parametric dependence on film thickness, inertia and capillarity. Bistable resonance is computed for steep enough bottom undulations. As an analytic approach, we apply the integral boundary-layer method and derive an asymptotic equation valid for rather thin films. The analysis recovers the key numerical findings and provides qualitative understanding. It shows that higher harmonics are generated by a nonlinear coupling of the wall with lower-order harmonics of the free surface. It also accounts for bistable resonance, and produces a minimum model whose solution is similar to that of the Duffing oscillator. 相似文献
16.
N. Aksel 《Archive of Applied Mechanics (Ingenieur Archiv)》2000,70(1-3):81-90
Summary In creeping flows of thin films, the capillarity can play a dominant role. In this paper, the creeping film flow down an
inclined plane with an edge is considered. The influence of the capillarity on the velocity and the film surface is studied
analytically, numerically and experimentally.
Received 12 April 1999; accepted for publication 9 May 1999 相似文献
17.
18.
Mustafa Yıldız Hava Özay Hüseyin Ünver Nazan Ocak İskeleli D. Mehmet Zengin Tahsin Nuri Durlu 《Journal of chemical crystallography》2010,40(11):909-913
Abstract
Schiff base (E)-2-[(benzo[d]thiazol-2-ylimino)methyl]phenol (1) has been synthesized from the reaction of 2-hydroxy-benzaldehyde with 2-aminobenzothiazole. The 2-[(benzo[d]thiazol-2-ylamino)methyl]phenol (2) was prepared reduction of the Schiff base 1 with sodium borohydride. The compounds 1 and 2 have been characterized by elemental analysis, FT-IR, 1H-NMR, 13C-NMR and UV–visible spectroscopic techniques. The structure of the compound 2 has also been examined crystallographically. The compound 2 crystallizes in the monoclinic space group P2/c. The unit cell parameters were found as a = 10.017(1), b = 11.725(1), c = 10.341(1) ?, V = 1208.1(1) ?3, D x = 1.409 g cm−3 and Z = 4. The crystal structure was solved by direct methods and refined by the full-matrix least squares method and found as R 1 = 0.0308 and wR 2 = 0.0818 for 2032 for the observed reflections [I > 2σ(I)]. 相似文献19.
The exact and the asymptotic non-null distribution of the maximal invariant corresponding to testing that the covariance matrix of a 2m-dimensional real normal distribution has complex structure is obtained. 相似文献
20.
Jan Finjord Aksel Hiorth Unn H. a Lad Svein M. Skjæveland 《Transport in Porous Media》2007,69(1):33-53
We consider analytical and numerical solution of NMR relaxation under the condition of surface relaxation in an equilateral
triangular geometry. We present an analytical expression for the Green’s function in this geometry. We calculate the transverse
magnetic relaxation without magnetic gradients present, single-phase, both analytically and numerically. There is a very good
match between the analytical and numerical results. We also show that the magnetic signal from an equilateral triangular geometry
is qualitatively different from the known solution: plate, cylinder, and sphere, in the case of a nonuniform initial magnetization.
Nonuniform magnetization close to the sharp corners makes the magnetic signal very fast multiexponential. This type of initial
configuration fits qualitatively with the experimental results by Song (Phys. Rev. Lett. 85, 3878 (2000)), Song et al. (Nature
406, 178 (2000)), Song (Mag. Reson. Imag. 19, 417 (2001)) and Lisitza and Song (Phys. Rev. B
65, 172406 (2002)). It should also be noted that the solution presented here can be used to describe absorption of a chemical
substance in an equilateral triangular geometry (for a stationary fluid). 相似文献