排序方式: 共有219条查询结果,搜索用时 171 毫秒
21.
Yakov Itin 《General Relativity and Gravitation》1999,31(2):187-203
The wave type field equationa =a, where ais a coframe field on a space-time, was recentlyproposed to describe the gravity field. This equationhas a unique static, spherically symmetric, asymptotically flat solution, whichleads to the viable Yilmaz–Rosen metric. We showthat the wave type field equation is satisfied by thepseudo-conformal frame if the conformal factor isdetermined by a scalar 3D-harmonic function. This functioncan be related to the Newtonian potential of classicalgravity. So we obtain a direct relation between thenon-relativistic gravity and the relativistic model: every classical exact solution leads to asolution of the field equation. With this result weobtain a wide class of exact, static metrics. We showthat the theory of Yilmaz relates to thepseudo-conformal sector of our construction. We derive also aunique cosmological (time dependent) solution of thedescribed type. 相似文献
22.
《Quaestiones Mathematicae》2013,36(1):35-44
We prove the existence of Gorenstein injective envelopes and covers over n-perfect rings for some classes of modules associated with a dualizing bimodule. 相似文献
23.
Peichu Hu Chungchun Yang 《分析论及其应用》2005,21(2):101-117
In this paper, we will introduce some problems and results between Diophantine approximation and value distribution theory. 相似文献
24.
In 1975, Ashtekar and Magnon showed that anenergy condition selects a unique quantization procedurefor hypersurface orthogonal observers in general, curvedspacetimes. We generalize this result in two important ways, by eliminating the need toassume a particular form for the (quantum) Hamiltonian,and by considering the surprisingly nontrivial extensionto non-minimal coupling, for which the classical Hamiltonian differs from the classical energycalculated from the stress-energy tensor. 相似文献
25.
Carlos A. López 《General Relativity and Gravitation》1997,29(9):1095-1098
It is shown that uncharged test particles, released from rest at infinity in the Kerr-Newman field, stop and rebound when the radial coordinate r takes the value r0 = Q2/(2M). This expression corresponds to the position of a stationary source of the Kerr-Newman field found by the author. It represents the surface of a massive oblate ellipsoid of revolution undergoing rigid rotation. Besides, the magnitude of r0 guarantees that no violation of causality occurs throughout spacetime. Although the test particles' angular momenta are always zero, they acquire a rotational motion as a consequence of the dragging of inertial frames. 相似文献
26.
27.
Alexander I. Nesterov 《General Relativity and Gravitation》1997,29(9):1115-1122
We study topology change in (2+1)D gravity coupling with non-Abelian SO(2, 1) Higgs field from the point of view of Morse theory. It is shown that the Higgs potential can be identified as a Morse function. The critical points of the latter (i.e. loci of change of the spacetime topology) coincide with zeros of the Higgs field. In these critical points the two-dimensional metric becomes degenerate, but the curvature remains bounded. 相似文献
28.
L. C. Garcia de Andrade 《General Relativity and Gravitation》1998,30(11):1629-1637
Two classes of non-Riemannian domain walls are obtained as distributional planar sources for the linearized Einstein-Cartan (EC) field equations of gravity. The first class represents spin polarized particles distributed on the non-Minkowskian side of the wall and an analogy with the ferromagnetic domains is displayed since the spin distributions are different on both sides of the walls. The other class represents a gravitational analog of Type I superconductor where Cartan torsion plays the role of the magnetic field. The interior solution is obtained by using matching conditions in EC-gravity and is matched to a torsionless vacuum in the last case. 相似文献
29.
用LKB2277生物活性检测系统测定了三种厌氧菌---吉氏类杆菌、艰难梭状芽胞杆菌、黑色消化球菌的生长发热功率曲线。根据广义logistic方程, 建立了细菌生长过程的热动力学方程:ln[P/(Pm-P)^v^+^1]=ln[P0/(Pm-P0)^v^+^1]+k.t。由此热动力学方程, 求得了细菌的生长常数k, 根据Arrhenius公式求得吉氏菌的生长活化能Ea=59.7kj/mol, 应用过渡态理论得到吉氏菌在不同温度下的活化力学参数, 这个热动力学方程描述的是一系列不规则的细菌生长过程发热曲线, 将它与经典的指数模型和logistic模型进行比较, 它具有更广泛的适用性。 相似文献
30.
电负性标度和电子亲和能的规律性研究II. 电子亲和能的规律性研究 总被引:1,自引:0,他引:1
本文研究了不同情形下, 绝对硬度η与~nt(r为轨道半径, n, I 为轨道的主量子数和角量子数)的关系, 并在前文提出的Z/~nl与Mulliken 电负性关系基础上, 将元素电子亲和能A同时与Z/~nl和~nl相关起来, 并表示成A=αZ/~nl+b~nb+c(a, b, c为常数)。我们研究了这种关系在周期表中各族及各过渡系的拟合结果, 不但计算值与电子亲和能的实验值非常吻合, 而且拟合的相关程度很高。本文方法为系统研究电子亲和能的变化规律提供了简单可行的途径。 相似文献