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In a recent article [Physics Letters A 372 (2008) 417], Wang et al. proposed a method, which is called the (G′/G)-expansion method, to look for travelling wave solutions of nonlinear evolution equations. The travelling wave solutions involving parameters of the KdV equation, the mKdV equation, the variant Boussinesq equations, and the Hirota-Satsuma equations are obtained by using this method. They think the (G′/G)-expansion method is a new method and more travelling wave solutions of many nonlinear evolution equations can be obtained. In this paper, we will show that the (G′/G)-expansion method is equivalent to the extended tanh function method. 相似文献
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A 2+1 version of a rotating perfect fluid spacetime of Gödel type is examined to see whether it has a Finkelstein-Misner kink. It is shown, by three different methods, that the kink number is one. 相似文献
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引力相互作用是物理世界的四种1)基本相互作用之一.它的耦合常数为引力常数G.本文将介绍近年来有关G的理论和测量的进展. 一、G又被重视起来了 引力常数G是人类测量得最早的基本物理常数.远在1798年,卡文迪什已经用扭秤测出了引力常数G,并且用它估计过地球的质量.由于引力相互作用是四种基本相互作用中最弱的一种,G的精确测量是非常困难的.G又没有什么用处[1],使得以后G的测量研究长期陷于停顿的状态.直到1969年,G的测量精度还几乎停留在卡文迪什的水平,只有三位有效数.有人分析甚至不超过1/500[2]. 近年来随着广义相对论理论研究的进展… 相似文献
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In this paper,we use the fractional complex transform and the(G'/G)-expansion method to study the nonlinear fractional differential equations and find the exact solutions.The fractional complex transform is proposed to convert a partial fractional differential equation with Jumarie’s modified Riemann–Liouville derivative into its ordinary differential equation.It is shown that the considered transform and method are very efficient and powerful in solving wide classes of nonlinear fractional order equations. 相似文献
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通过G e o G e b r a软件绘制了理想气体状态方程的三维立体图, 并在三维图中分析了教学中常见的等温
线、 等压线、 等容线, 为理想气体状态方程提供了另一种教学视角 相似文献
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In this article, we propose an alternative approach of the generalized and improved (G'/G)-expansion method and build some new exact traveling wave solutions of three nonlinear evolution equations, namely the Boiti- Leon-Pempinelle equation, the Pochhammer-Chree equations and the Painleve integrable Burgers equation with free parameters. When the free parameters receive particular values, solitary wave solutions are constructed from the traveling waves. We use the Jacob/elliptic equation as an auxiliary equation in place of the second order linear equation. It is established that the proposed algorithm offers a further influential mathematical tool for constructing exact solutions of nonlinear evolution equations. 相似文献
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万有引力常数G是人类历史上引入的第一个基本物理学常数,其在理论物理、天体物理和地球物理等许多领域中扮演着重要角色.两百多年来,人们共测量出了200多个G值,但G的测量精度仍然是所有物理学常数中最差的,这一现象反映了测G工作本身的复杂性和困难性.本文简要概述了G值测量的意义和测G的历史,并结合自2010年以来国际上新出现的三个高精度测G实验介绍这一领域的研究进展,以及华中科技大学引力实验中心测G工作的最新动态. 相似文献
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引力常量G是一个重要的普适常量,自从1798年英国物理学家卡文迪什(H.Cavendish)用扭秤第一次精确地测定了G以来,200年间,很多实验工作者对G进行测量所用的方法大体上都是在扭秤法基础上的改进,测量精度几乎仍停留在三位有效数字. 相似文献
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We investigate the geodesic curves of the homogeneous Gödel-type space-times, which constitute a two-parameter (l and ) class of solutions presented to several theories of gravitation (general relativity, Einstein-Cartan and higher derivative). To this end, we first examine the qualitative properties of those curves by means of the introduction of an effective potential and then accomplish the analytical integration of the equations of motion. We show that some of the qualitative features of the free motion in GSdel's universe (l
2=22) are preserved in all space-times, namely: (a) the projections of the geodesics onto the 2-surface (r, ) are simple closed curves (with some exceptions forl
242), and (b) the geodesies for which the ratio of azimuthal angular momentum to total energy,, is equal to zero always cross the originr=0. However, two new cases appear: (i) radially unbounded geodesies with assuming any (real) value, which may occur only for the causal space-times (l
242), and (ii) geodesies with bounded both below and above, which always occur for the circular family (l
2<0) of space-times. 相似文献
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Ernst RR 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,173(2):188-191
The Günther Laukien Prize, established in 1999, intends to recognize recent cutting-edge experimental NMR research with a high probability of enabling beneficial new applications. It is awarded yearly at the Experimental NMR Conference (ENC). 相似文献
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本文采用分子动力学模拟和结合自由能计算研究了抑制剂G4G与HIV-1蛋白酶的作用机制。研究结果表明范德华作用主导了抑制剂G4G与HIV-1蛋白酶的结合。基于残基的自由能计算表明残基Gly49、Ile50、Val82、Ile84、Gly27′、Ala28′、Ile50′和Ile84′与G4G产生了较强的相互作用,同时研究也表明CH-π,CH-O相互作用和氢键是其主要的作用形式。该研究能为以HIV-1蛋白酶为靶标的抗艾滋病药物设计提供理论上的指导。 相似文献