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本文考虑到地球自转的影响,应用引力场强的概念,导出了质点在地球中任意一条光滑隧道内运动的微分方程.同时指出:在某些特殊隧道内的自由质点,其运动是简谐振动,但对于其它隧道来说,质点从一端进入后,或者作简谐振动而以隧道中某点为返转点,或者从另一端抛出而不再返回. 相似文献
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本文根据直线来与曲线(c)间的交角公式导出ctg=r'(θ)/r(θ)的形式,由此微分方程可得到 r(θ) 的积分式,便可直接求得极坐标形式的质点运动的轨 道方程.此法给解决质点运动轨迹的问题带来方便. 相似文献
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本文研究了均匀重力场中的质点在光滑圆柱面上的挠曲线运动,用牛顿定律或拉格朗日方程推导质点的运动微分方程,然后解得质点脱离圆柱面的位置满足的方程以及脱离前的运动时间,最后导出用椭圆积分表示的挠曲线运动轨迹的参数解析表达式。 相似文献
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用把方程的解设为余弦函数多项式的一种直接方法,求解了受幂律引力作用的质点一类非线性轨道微分方程,从而得出在幂律引力作用下从拱点抛出质点的运动轨道是正弦螺线。 相似文献
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从陈子定理可以演绎出描写质点运动的各种表示方式,从陈子定理可以推导出质点动力学的基本定理,包括牛顿运动三定律,动能定理,质心运动定理。 相似文献
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利用直角坐标系中的质点运动微分方程和机械能守恒定律,推导出质点沿竖直面内任意的光滑曲线运动过程中单侧约束解除点的一般公式,并用它研究了约束曲线是二次曲线、立方抛物线、正弦曲线、双曲正弦线和普通摆线的情况. 相似文献
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In the Standard Model (and MSSM), renormalization effects on neutrino mixing are generally very small and the attractive fixed points are at vanishing neutrino mixing. However for multi-Higgs extensions of the Standard Model, renormalization effects on neutrino mixing can be large and nontrivial fixed points are possible. Here we examine a simple two-Higgs model. For two flavors, maximal mixing is an attractive infrared fixed point. For three flavors, the neutrino mass matrix evolves towards large off-diagonal elements at low energies. The experimentally suggested bimaximal neutrino mixing pattern is one possible attractive infrared fixed point. 相似文献
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辐射压是影响大质量恒星结构和演化不可忽视的重要物理因素. 根据辐射压对非同步转动的洛希势函数的影响, 数值计算了洛希瓣的大小和3个拉格朗日点的位置和相应的势函数, 并与同步转动的洛希模型计算的结果做了对比. 结果发现: 辐射压可以整体地减小大质量恒星表面的重力加速度, 而转动离心力能最大减少赤道附近的重力加速度. 辐射压和非同步转动均可以明显地改变洛希瓣的大小和3个拉格朗日点的位置和势函数, 影响双星系统物质交换的时间. 因此, 研究辐射压, 非同步转动等物理因素对大质量双星系统洛希势函数的影响, 对密近双星的演化具有重要意义.
关键词:
恒星结构与演化
转动
辐射压 相似文献
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B. P. Kondratyev 《Physics of Particles and Nuclei Letters》2011,8(5):431-435
A theory of equigravitating bodies by which external force fields of volumetric axially symmetric figures can be represented
by unitary integrals is developed. This theory is being developed in three directions. The first is connected with the proof
of the existence of equigravitating line segments. Such line segments can have both real and imaginary distributions of density;
however, the mass and external potential remain real values. The ends of line segments coincide with special points (these
are cusp points on the surfaces or special points of the analytical continuation of the external potential inside the body).
At two special points, the body has only one line equigravitating segment, otherwise the line segments are compound or form
equigravitating “skeletons.” At the isolated special points, external gravitational fields can be presented by a set of line
segments and mass points. The second direction is based on a representation of the external gravitational field of volumetric
axially symmetric figures with an equator plane by means of potentials of flat round disks. Such disks are obtained on the
line segments with symmetric density distributions. The return is always true: for homogeneous or any nonuniform round disk,
it is possible to find an equigravitating line segment. It manages to construct chains of “spheroid-disk-line segment” equigravitating
bodies. The third direction of this theory is connected with the development and expansion on the scope of the method of confocal
transformations. This method is modified and applied not only to continuous homogeneous ellipsoids, but also to non-uniform
stratified ellipsoids with a stratification of the general type, as well as to homogeneous and nonuniform shells. Any elementary
or thick ellipsoidal shells (and continuous nonuniform stratified ellipsoids) connected by special confocal transformations
equigravitate each other. 相似文献
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We study the ergodic properties of three classical particles of unequal mass moving on a ring and colliding like hard points.Although it is generally believed that this system is ergodic, we show that extensive numerical calculations do not support this belief.This may be connected with our discovery that for vanishing total momentum, any initial state with one particle at rest is periodic, independent of the mass values.The analogous periodicity for two unequal mass particles bouncing in a one-dimensional box can be understood on the basis of a remarkable property of a billiard in the form of a rectangular triangle. 相似文献
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Daniel Pa?ca 《Physica D: Nonlinear Phenomena》2010,239(16):1516-1766
The present paper studies the escape mechanism in collinear three point mass systems with small-range-repulsive/large-range-attractive pairwise interaction. Specifically, we focus on the asymptotic behaviour for systems with non-negative total energy.On the zero energy level set there are two distinct asymptotic states, called 1+1+1escape configurations, where all the three separations infinitely increase as t→∞. We show that 1+1+1 escapes are improbable by proving that the set of initial conditions leading to such asymptotic configurations has zero Lebesgue measure. When the outer mass points are of the same kind we deduce the existence of a heteroclinic orbit connecting the 1+1+1 escape configurations. We further prove that this orbit is stable under parameter perturbation.In the positive energies’ case, we show that the set of initial conditions leading to 1+1+1 escape configurations has positive Lebesgue measure. 相似文献
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Xia Ma Paul T. GiguereBalaji Jayaraman Duan Z. Zhang 《Journal of computational physics》2010,229(20):7819-7833
When using the time explicit material point method to simulate interaction of materials accompanied by large deformations and fragmentation, one often encounters a numerical instability caused by small node mass, because acceleration on a mesh node is obtained by dividing the total force on the node by the mass of the node. When the material points are in the far sides of the cells containing the node, typically happening near material interfaces, the node mass can be very small leading to artificially large acceleration and then numerical instability. For the case of small material deformations, this instability is typically avoided by placing the material points away from cell boundaries. For cases with large deformations, with the exception of initial conditions, there is no control on locations of the material points. The instability caused by small mass nodes is often encountered. To avoid this instability tiny time steps are usually required in a numerical calculation. 相似文献
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We have investigated the appearance of chaos in the one-dimensional Newtonian gravitational three-body system (three masses on a line with -1/r pairwise potential). In the center of mass coordinates this system has two degrees of freedom and can be conveniently studied using Poincare sections. We have concentrated in particular on how the behavior changes when the relative masses of the three bodies change. We consider only the physically more interesting case of negative total energy. For two mass choices we have calculated 18 000 full orbits (with initial states on a 100x180 lattice on the Poincare section) and obtained dwell time distributions. For 105 mass choices we have calculated Poincare maps for 10x18 starting points. Our results show that the Poincare section (and hence the phase space) divides into three well defined regions with orbits of different characteristics: (1) There is a region of fast scattering, with a minimum of pairwise collisions. This region consists of 'scallops' bordering the E=0 line, within a scallop the orbits vary smoothly. The number of the scallops increases as the mass of the central particle decreases. (2) In the chaotic scattering region the interaction times are longer, and both the interaction time and the final state depend sensitively on the starting point on the Poincare section. For both (1) and (2) the initial and final states consist of a binary + single particle. (3) The third region consists of quasiperiodic orbits where the three masses are bound together forever. At the center of the quasiperiodic region there is a periodic orbit discovered (numerically) by Schubart in 1956. The stability of the Schubart orbit turns out to correlate strongly with the global behavior. 相似文献
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Rodríguez D Kolhinen VS Audi G Aystö J Beck D Blaum K Bollen G Herfurth F Jokinen A Kellerbauer A Kluge HJ Oinonen M Schatz H Sauvan E Schwarz S 《Physical review letters》2004,93(16):161104
The mass of one of the three major waiting points in the astrophysical rp process 72Kr was measured for the first time with the Penning trap mass spectrometer ISOLTRAP. The measurement yielded a relative mass uncertainty of deltam/m=1.2x10(-7) (deltam=8 keV). (73,74)Kr, also needed for astrophysical calculations, were measured with more than 1 order of magnitude improved accuracy. We use the ISOLTRAP masses of 72-74Kr to reanalyze the role of 72Kr (T(1/2)=17.2 s) in the rp process during x-ray bursts and conclude that 72Kr is a strong waiting point delaying the burst duration with at least 80% of its beta-decay half-life. 相似文献