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791.
本文讨论了四对谱问题、相应保谱发展方程族以及它们 Lax表示的等价性 ,并利用这种等价关系导出了一些方程的 Lax表示 . 相似文献
792.
本文用通俗的方法介绍了广义相对论的基本思想 ,并得到了史瓦西场时空弯曲的规律及质点在史瓦西场中自由运动的规律 ,从而解决了引力红移 ,CS原子钟环地球飞行后与地面上 CS原子钟的时差 ,行星进动 ,光子经过太阳表面时的偏转角 ,雷达回波延迟等问题 . 相似文献
793.
A. I. Miller 《Physics in Perspective (PIP)》1999,1(1):85-104
Jahrbuch paper is an extraordinary document because it contains his first steps toward generalizing the 1905 relativity theory to
include gravitation. Ignoring the apparent experimental disconfirmation of the 1905 relativity theory and his unsuccessful
attempts to generalize the mass-energy equivalence, Einstein boldly raises the mass-energy equivalence to an axiom, invokes
equality between gravitational and inertial masses, and then postulates the equivalence between a uniform gravitational field
and an oppositely directed constant acceleration, the equivalence principle. How did this come about? What is at issue is
scientific creativity. This necessitates broadening historical analysis to include aspects of cognitive science such as the
role of visual imagery in Einstein's thinking, and the relation between conscious and unconscious modes of thought in problem
solving. This method reveals the catalysts that sparked a Gedanken experiment that occurred to Einstein while working on the Jahrbuch paper. A mental model is presented to further explore Einstein's profound scientific discovery. 相似文献
794.
本文主要给出*-模的一些充分必要条件,同时还证明了:如果f:R→S是环同态,RP是P-投射模,当RP是*-模,Tilting模,拟Tilting模时,S RP也分别是*-模,Tilting模,和拟Tilting模。 相似文献
795.
Yu. A. Chirkunov 《Journal of Applied Mechanics and Technical Physics》2009,50(2):213-219
An algorithm is proposed which allows all conservation laws for a system of differential equations to be to obtained from
its one zero-order conservation law for which the general rank of the Jacobi matrix is equal to the number of independent
variables of the system. The efficiency of the algorithm is shown by examples of the equations of gas dynamics, for which
new conservation laws are derived. For the equations considered, additional symmetry properties related to these conservation
laws are established.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 2, pp. 53–60, March–April, 2009. 相似文献
796.
In this work, sandwich beams are studied to reveal the underlying size effects of the periodic core cells for the first time within the framework of free vibration analysis of such an advanced lightweight structure. The energy equivalence method is formulated as a theoretical approach that takes into account the cell size effect. It is compared with the asymptotic homogenization method and direct finite element method systematically to show their consistence and applicability. The accuracy of free vibration responses predicted by the detailed finite element model is used as the standard of comparison. It is shown that the cell size is an important parameter characterizing the cellular core rigidities that influence vibration responses. The homogenization model agrees exactly with the asymptotic solution of the analytical expression of the beam model only whenever the cell size tends to be infinitely small. 相似文献
797.
For a long time, it has been generally believed that spin-spin interactions can only exist in a theory where Lorentz symmetry is gauged, and a theory with spin-spin interactions is not perturbatively renormalizable. But this is not true. By studying the motion of a spinning particle in gravitational field, it is found that there exist spin-spin interactions in gauge theory of gravity. Its mechanism is that a spinning particle will generate gravitomagnetic field in space-time, and this gravitomagnetic field will interact with the spin of another particle, which will cause spin-spin interactions. So, spin-spin interactions are transmitted by gravitational field. The form of spin-spin interactions in post Newtonian approximations is deduced. This result can also be deduced from the Papapetrou equation. This kind of interaction will not affect the renormalizability of the theory. The spin-spin interactions will violate the weak equivalence principle, and the violation effects are detectable. An experiment is proposed to detect the effects of the violation of the weak equivalence principle. 相似文献
798.
樊馨蔓 《浙江大学学报(理学版)》2013,40(5):499-501
利用幂等元刻画了自同态正则分裂图的自同态幺半群的ρf 类和自同态像的个数,进而得到了〖L〗类及〖R〗类的个数. 相似文献
800.
本文在余代数上定义了五类等价关系,它们是Green等价G,D,L,R,H.然 后给出了这些等价关系一些基本性质和结构特点.在每个Green等价的等价类集上构 造了一种偏序并给出了偏序上半格和格结构的刻划.用G-,L-,R-类分别给出了子余 代数、左余理想、右余理想的结构刻划.进一步地,本文研究了张量积上的Green等 价以及余代数同态的Green保持性和提升性.作为应用,本文得到了两个不可约余代 数的张量积仍为不可约余代数的一个条件;证明了不可约余代数在G-保持余代数同 态下的同态像是不可约的. 相似文献