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991.
992.
A high accuracy test of the weak equivalence principle(WEP) is of great scientific significance no matter whether its result is positive. We analyze the gravity gradient effect which is a main systematic error source in the test of WEP.The result shows that the uncompensated gravity gradient effect from the coupling term of the dominated gravity gradient multipole moment component q_(21) and the relative multipole field component Q_(21) contributes to an uncertainty of 1×10~(-11) on the E¨otv¨os parameter. We make a Q_(21) compensation to reduce the effect by about 20 times, and the limit of the test precision due to this coupling is improved to a level of a part in 10~(13). 相似文献
993.
In this paper we study a reaction–diffusion–advection predator–prey model in a river. The existence of predator-invasion traveling wave solutions and prey-spread traveling wave solutions in the upstream and downstream directions is established and the corresponding minimal wave speeds are obtained. While some crucial improvements in theoretical methods have been established, the proofs of the existence and nonexistence of such traveling waves are based on Schauder’s fixed-point theorem, LaSalle’s invariance principle and Laplace transform. Based on theoretical results, we investigate the effect of the hydrological and biological factors on minimal wave speeds and hence on the spread of the prey and the invasion of the predator in the river. The linear determinacy of the predator–prey Lotka–Volterra system is compared with nonlinear determinacy of the competitive Lotka–Volterra system to investigate the mechanics of linear and nonlinear determinacy. 相似文献
994.
刘远全 《原子与分子物理学报》2017,34(4):644-648
本文采用第一性原理研究了(NaP_3)_n(n=1~5)团簇的几何结构、能隙、电荷分布以及态密度.研究结果表明:NaP_3团簇为线型结构,是(NaP_3)_n(n=1~5)团簇中的基本单元,随着n增大,团簇转变为环状结构和空间结构;(NaP_3)_3团簇的能隙出现峰值,表明该团簇较其他团簇有较高的稳定性;(NaP_3)_3团簇中对于高能量区域的态密度是由Na 3s和P 3p轨道贡献,其中在费米附近的能量主要由P 3p轨道贡献,对于低能量区域的态密度主要由Na 3s轨道贡献;(NaP_3)_n(n=1~5)团簇中的Na原子电荷分布均为正值,表明电荷总体上是从Na原子转移到P原子. 相似文献
995.
In this paper, we investigate the mean squared derivative cost functions that arise in various applications such as in motor control, biometrics and optimal transport theory. We provide qualitative properties, explicit analytical formulas and computational algorithms for the cost functions. We also perform numerical simulations to illustrate the analytical results. In addition, as a by‐product of our analysis, we obtain an explicit formula for the inverse of a Wronskian matrix that is of independent interest in linear algebra and differential equations theory. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
996.
M. V. Dolgopolik 《Optimization》2017,66(10):1577-1622
In this article, we develop a general theory of exact parametric penalty functions for constrained optimization problems. The main advantage of the method of parametric penalty functions is the fact that a parametric penalty function can be both smooth and exact unlike the standard (i.e. non-parametric) exact penalty functions that are always nonsmooth. We obtain several necessary and/or sufficient conditions for the exactness of parametric penalty functions, and for the zero duality gap property to hold true for these functions. We also prove some convergence results for the method of parametric penalty functions, and derive necessary and sufficient conditions for a parametric penalty function to not have any stationary points outside the set of feasible points of the constrained optimization problem under consideration. In the second part of the paper, we apply the general theory of exact parametric penalty functions to a class of parametric penalty functions introduced by Huyer and Neumaier, and to smoothing approximations of nonsmooth exact penalty functions. The general approach adopted in this article allowed us to unify and significantly sharpen many existing results on parametric penalty functions. 相似文献
997.
Marius Măntoiu 《偏微分方程通讯》2017,42(11):1659-1681
By using commutator methods, we show uniform resolvent estimates and obtain globally smooth operators for self-adjoint injective homogeneous operators H on graded groups, including Rockland operators, sublaplacians, and many others. Left or right invariance is not required. Typically the globally smooth operator has the form T = V|H|1∕2, where V only depends on the homogeneous structure of the group through Sobolev spaces, the homogeneous dimension and the minimal and maximal dilation weights. For stratified groups improvements are obtained, by using a Hardy-type inequality. Some of the results involve refined estimates in terms of real interpolation spaces and are valid in an abstract setting. Even for the commutative group ?N some new classes of partial differential operators are treated. 相似文献
998.
材料强度理论研究是高等材料力学的一个重要研究领域,200多年来,各国学者提出了许多强度理论及试验研究结果.这些理论都是从不同的假设和力学模型出发,推导出不同的数学表达式,但一般只适用于某一类特定的材料.各种强度理论之间是否有联系?是否可能建立一个广泛适用的统一强度理论?自19世纪末以来,世界各国学者都在努力寻求建立统一强度理论,但一直没有成功.本文应用理论研究和试验验证相结合的方法,提出并验证了三剪应力统一强度理论。认为当作用于菱形十二面单元体上的三个主剪应力及其作用面上的三个正应力的函数达到某一极限值时,材料发生破坏.三剪应力统一强度理论是全应力理论,它用一个统一的线性表达式包含或逼近了现有的和其他新的各种单一和统一、线性和非线性、外凸和非凸的强度理论,形成了以单剪强度理论为下限、而以三剪应力强度理论为上限的一系列强度理论的新体系,实现了外凸强度理论和非凸强度理论的高度统一,使强度理论从适用于某一类材料、某种应力状态的单一强度理论发展为可以适用于各种材料及不同应力状态的统一强度理论,并能更大程度地发挥材料的强度潜力.通过与大量试验结果的对比分析表明：三剪应力统一强度理论可以广泛适用于各种材料及其不同的应力状态. 相似文献
999.
1000.
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