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111.
IntroductionTheproblemofaconesubjectedtoconcentratedloadsatitsapexisaclassicalprobleminthetheoryofelasticity.AnumberofscholarshavestUdiedtheproblem.LovereportedthesolutionstotheproblemofanisotropicconeunderconcentfatCdforcesatitsapex['].Lur'estudiedthisclassofproblemssystematicallybymeansofPapkovich-Neubergeneralsolution[2].LekniskiiandHu,byusingtheirrespectivegeneralsolutions,studiedcompressionandbendingproblemsofatransverselyisotropicconesubjectedtoaxialconcentfatedforcesandtfansverseconc… 相似文献
112.
ZHANG Cheng-Min 《理论物理通讯》2005,44(8)
In the framework of parallelism general relativity, the torsion axial-vector in the rotating gravitational field is studied in terms of the alternative Kerr tetrad. In thecase of the weak field and slow rotation approximation, we obtain that the torsion axial-vector possesses the dipole-like structure. Furthermore, the effect of massive neutrino spin precession in this field is mentioned. 相似文献
113.
M. B. Shundalov G. A. Pitsevich M. A. Ksenofontov D. S. Umreiko 《Journal of Applied Spectroscopy》2009,76(3):325-333
We present results of ab initio and DFT calculations of the structure, potential functions of the methyl group internal rotation and the amino group inversion,
and vibrational frequencies and intensities in IR and Raman spectra of methylcarbamate. The calculations were carried out
using different basis sets in the HF, MP2, and DFT/B3LYP approximations. The influence of both the basis set size and the
allowance for electronic correlation on peculiarities of the structure of the amino group in methylcarbamate has been analyzed.
It is shown that the B3LYP/6-311++G(2d, p) and B3LYP/cc-pVDZ calculations reproduce highly accurately experimental geometric
parameters of methylcarbamate. Parameters of torsional and inversion potentials and characteristics of vibrational spectra
calculated in different approximations show satisfactory agreement with experimental values.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 349–357, May–June, 2009. 相似文献
114.
在研制基于微型光机电系统技术的光电器件过程中,需要精确测定器件在给定驱动条件下的运动情况。在对制作完成的光开关进行性能测试时,由于微型光机电系统光开关的几何尺寸的限制,如果要准确测定光开关微反射镜的运动位移。将会有一定的困难。提出了一种采用线阵CCD技术的光学测量方法,实现了对光开关悬臂梁在驱动电压作用下的旋转角度的精确测量。通过理论推导得到了悬臂梁扭转角度与可测量物理量的关系.通过求解方程得到了各个物理量的数值选择对于测量结果的影响,并且给定了测量时各个物理量的参考值。通过实验测量,误差小于10%,表明这是一种具有实际意义的测量方案。 相似文献
115.
V. N. Paimushin V. A. Ivanov S. A. Lukankin N. V. Polyakova V. A. Firsov S. A. Kholmogorov 《Mechanics of Composite Materials》2009,45(2):113-136
Based on linearized equations of the theory of elastic stability of straight composite bars with a low shear rigidity, which
are constructed using the consistent geometrically nonlinear equations of elasticity theory for small deformations and arbitrary
displacements and a kinematic model of Timoshenko type, exact analytical solutions of nonclassical stability problems are
obtained for a bar subjected to axial compression and torsion for various modes of end fixation. It is shown that the problem
of direct determination of the critical parameter of the compressive load at a given torque parameter leads to transcendental
characteristic equations that are solvable only if bar ends have cylindrical hinges. At the same time, we succeeded in obtaining
solutions to these equations in terms of wave formation parameters of the bar; these parameters, in turn, enabled us to find
the parameter of the critical load at any boundary conditions. Also, an algorithm for numerical solution of the problems stated
is proposed, which is based on reducing the problems to systems of integroalgebraic equations with Volterra-type operators
and on solving these equations by the method of mechanical quadratures (finite sums). It is demonstrated that such numerical
solutions exist only for certain ranges of parameters of the bar and of the parameter of torque. In the general case, they
can not be obtained by the numerical method used. It is also shown that the well-known solutions of the stability problem
for a bar subjected to torsion or to compression with torsion are in correct.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 45, No. 2, pp. 167–200, March–April, 2009. 相似文献
116.
Jinsung Park 《Journal of Functional Analysis》2009,257(6):1713-1758
In this paper we derive a relationship of the leading coefficient of the Laurent expansion of the Ruelle zeta function at s=0 and the analytic torsion for hyperbolic manifolds with cusps. Here, the analytic torsion is defined by a certain regularized trace following Melrose [R.B. Melrose, The Atiyah-Patodi-Singer Index Theorem, Res. Notes Math., vol. 4, A.K. Peters, Ltd., Wellesley, MA, 1993]. This extends the result of Fried, which was proved for the compact case in [D. Fried, Analytic torsion and closed geodesics on hyperbolic manifolds, Invent. Math. 84 (3) (1986) 523-540], to a noncompact case. 相似文献
117.
基于扭秤测量冲量原理,结合激光干涉法差动测量角度的方法,提出一种基于扭秤的激光干涉差动测量微小冲量的方法。介绍系统的基本组成和测量过程,给出扭秤结构设计参数,并对系统参数进行了标定,结合设计参数与标定结果,对系统的分辨率、量程和精度进行了校核,在典型的测量环境下,对激光烧蚀靶材所形成的Ns量级微小冲量进行了测量,给出了典型的测量结果并进行分析。结果表明:所提出的基于扭秤的激光干涉差动测量微小冲量方法,系统分辨率可达10-7Ns量级,测量范围跨5个数量级,最大可以测量10-2Ns量级冲量,测量精度优于95%。 相似文献
118.
Zhenyu Xue Jonas Faleskog John W. Hutchinson 《International Journal of Solids and Structures》2013,50(25-26):4258-4269
An extension of the Gurson model that incorporates damage development in shear is used to simulate the tension–torsion test fracture data presented in Faleskog and Barsoum (2013) (Part I) for two steels, Weldox 420 and 960. Two parameters characterize damage in the constitutive model: the effective void volume fraction and a shear damage coefficient. For each of the steels, the initial effective void volume fraction is calibrated against data for fracture of notched round tensile bars and the shear damage coefficient is calibrated against fracture in shear. The calibrated constitutive model reproduces the full range of data in the tension–torsion tests thereby providing a convincing demonstration of the effectiveness of the extended Gurson model. The model reinforces the experiments by highlighting that for ductile alloys the effective plastic strain at fracture cannot be based solely on stress triaxiality. For nominally isotropic alloys, a ductile fracture criterion is proposed for engineering purposes that depends on stress triaxiality and a second stress invariant that discriminates between axisymmetric stressing and shear dominated stressing. 相似文献
119.
120.
Determination of the thermal noise limit in test of weak equivalence principle with a rotating torsion pendulum 下载免费PDF全文
Thermal noise is one of the most fundamental limits to the sensitivity in weak equivalence principle test with a rotating torsion pendulum. Velocity damping and internal damping are two of many contributions at the thermal noise, and which one mainly limits the torsion pendulum in low frequency is difficult to be verified by experiment. Based on the conventional method of fast Fourier transform, we propose a developed method to determine the thermal noise limit and then obtain the precise power spectrum density of the pendulum motion signal. The experiment result verifies that the thermal noise is mainly contributed by the internal damping in the fiber in the low frequency torsion pendulum experiment with a high vacuum. Quantitative data analysis shows that the basic noise level in the experiment is about one to two times of the theoretical value of internal damping thermal noise. 相似文献