引力辐射阻尼对双星轨道要素变化的影响——对过近星点时刻的影响

在文献［１］研究的基础上对双星引力辐射阻尼的效应又做了进一步研究．首先给出文献［１］的主要结果及其更正，然后利用文献［１］的结果又给出引力辐射阻尼对双星过近星点时刻的影响。结果表明，引力辐射阻尼对双星过近星点时刻不仅产生周期变化的效应，而且还产生长期变化的效应，这后者的效应使得双星过近星点时刻提前。最后利用所推出的结果对三颗双星（Ｙ Ｃｙｇ，ＰＳＲ２３０２＋２４．ＰＳＲＩ９１３＋１６）做了数值的长期效应的计算。 关键词：     

地磁场对带电人造卫星运动的影响

本文利用电磁学、理论力学等方法研究了带电的赤道卫星在地磁场中做椭圆轨道运动时地磁场对轨道运动的影响。研究结果表明:地磁场对带电卫星的轨道长轴没有摄动影响,但对轨道偏心率和近地点均有进动影响,且近地点不仅有周期变化影响而且还有长期变化影响。由计算实例表明:当卫星自身带电量较大时(如1库仑电量),这种影响必须予以考虑。     

旋转致密双星的引力波特征

研究了轨道和旋转效果到2.5阶后牛顿旋转致密双星拉格朗日动力学与引力波的关系, 分析了有序和混沌轨道的引力波特征.发现当加速度不考虑辐射项时, 有序双星系统辐射的引力波具有周期或拟周期的特征, 而混沌双星系统辐射的引力波却具有明显的混沌特征.当加速度含有辐射项贡献时, 双星必会出现并合现象.此时, 原保守有序双星系统需较长时间才能完成并合过程, 引力波形在双星并合前仍保留拟周期的基本特点;然而, 原保守混沌双星系统仅在较短时间内就会并合, 但因并合时间太短, 无法获取足够的动力学信息导致引力波形的特征不易分辨.     

致密双星后牛顿偏心轨道的引力波研究

本文主要研究非保守的后牛顿哈密顿自旋致密双星偏心轨道的引力辐射,数值比较保守的和非保守的自旋致密双星系统轨道参量偏心率大小与 引力波形的关系及引力辐射耗散效应项对轨道动力特性的影响. 数值研究表明：由于系统能量积分被保持,保守的双星轨道偏心率值改变对时域引力波形变化影响不是很明显,但辐射的引力波频率分布范围随着偏心率的增大而扩大. 而当运动方程中包含2.5PN引力耗散效应项时,由于引力辐射时伴随着能量和角动量损失,导致双星两体之间的距离和轨道偏心率逐渐衰减,轨道动力特性变得更加复杂. 双星旋进合并过程中辐射的引力波受到轨道偏心率的调制,引力辐射的强度随着偏心率的增大而增强,而引力辐射持续的时间缩短,且自旋与自旋耦合效应项对引力的贡献增大了. 关键词： 非保守的 引力辐射 耗散 偏心率     

旋转致密双星后牛顿轨道的引力波研究

本文利用辛算法和功率谱研究旋转致密双星保守的后牛顿哈密顿系统的引力辐射, 讨论了系统的动力学参量、旋转-轨道耦合、旋转-旋转耦合效 应及轨道类型对后牛顿近似引力波形的影响. 数值结果表明有序轨道的引力波随时间呈周期性地变化, 而混沌轨道引力波的变化具有混沌性, 并且轨道的混沌特性可提高引力波的辐射能量, 尤其指出的是旋转参量大小对引力波形的变化发挥至关重要的作用.     

转动双星同步和轨道圆化的物理过程研究

潮汐效应是影响恒星结构和演化非常重要的物理因素.本文研究了影响潮汐同步和轨道圆化的物理因素,如恒星质量、初始转速、轨道周期、金属丰度、对流超射等,并根据转动恒星的角动量转移和元素扩散方程,给出了这些因素对转动双星演化和元素混合的影响.结果表明：具有大质量子星、初始转速慢、对流超射小、轨道周期短的双星系统,能更早地达到平衡速度和轨道圆化;初始转速快的恒星,由于潮汐同步过程减速,双星系统中氮元素增丰没有单星的氮元素增丰显著;大质量星、高金属丰度、超射大和短周期的双星系统,氮增丰相对显著;质量小、金属丰度低、转速慢、超射大的恒星具有较小的恒星半径,而低金属丰度恒星表面却具有较高的有效温度,快速转动单星向低温和低光度端演化.     

从1993年度诺贝尔物理奖说起

 新闻报道泰勒(J．H．Taylor)和赫尔斯(R．AHulse)荣获1993年度诺贝尔物理奖。他们获得此项殊荣是意料中的,因为他们于1974年发现了一颗十分重要的双星脉冲星,名叫PSR1913+16。     

二维可积系统的求迹公式和周期轨道的量子化

从Berry–Tabor求迹公式出发,导出了二维可积系统周期轨道作用量的半经典量子化条件.利用此量子化条件,考虑周期轨道满足的周期条件,得到了二维无关联四次振子系统周期轨道作用量的半经典量子化条件,并给出了半经典能级公式.对能级与周期轨道的对应关系做了分析.     

可兴奋性细胞混沌放电区间的识别机理

在神经起步点记录到加周期分岔过程的生理实验数据，在对此分岔过程中位于周期n爆发 和周期(n+1)爆发之间的混沌的峰峰间期数据检测不稳定的周期轨道时，发现从靠近周期 n爆发的混沌的峰峰间期数据中，可以检测出不稳定的周期n轨道；而从靠近周期(n+1)爆 发的混沌的峰峰间期数据中，不仅可以检测出不稳定的周期(n+1)轨道，还可以检测出不稳 定的周期n轨道.针对该现象，借助于Sherman建议的胰腺β细胞模型，从非线性动力 学角度给出了理论解释.指明了由鞍结分岔和倍周期分岔分别产生第一类阵发和第三类阵发 为出现该 关键词： 峰峰间期 不稳定的周期轨道 鞍结分岔 倍周期分岔     

从1993年度诺贝尔物理奖说起

新闻报道泰勒(J．H．Taylor)和赫尔斯(R．AHulse)荣获1993年度诺贝尔物理奖。他们获得此项殊荣是意料中的,因为他们于1974年发现了一颗十分重要的双星脉冲星,名叫PSR1913+16。事实上,另一个大奖,1991年度日本的国际奖金“京都赏”(KyotoPrize,金额与诺贝尔奖金相     

The Post-Newtonian Effects of the Rotation of the Central Body on the Motion of the Celestial Body in Three Gravitational Theories

The post-Newtonian effects of the rotation of the central body on the variation of celestial orbital elements are studied according to the post-Newtonian metric theory. The variation of celestial orbital elements caused by the rotation of the central body in three gravitational theories of Einstein, Brans-Dicke and Nordtvedt is obtained by using the method of general perturbation. The resulting effects are the periodic variation of inclination, eccentricity and mean anomaly; the periodic and secular variation of longitudes of periastron and ascending node and mean longitudes of epoch, but the semimajor axis remains unperturbed (no variation). In addition, the obtained theoretical results are applied to the calculation of the post-Newtonian effect of the rotation of the sun on the variation of the orbital elements of planets in solar system. The numerical results are given in nble 1. Finally, the obtained results are discussed and compared with other theories.     

The Perturbation Effect of Rotating Solar Polytropic Model on the Variation of Planetary Orbital Elements

In this paper the author examines the perturbation effect of rotating solar polytropic model on the variation of planetary orbital elements by the method of general perturbation in celestial mechanics and the polytropic model ofgaseous star in astrophysics. The perturbation variables of planetary orbital elements caused by the rotation, oblateness and central density of the sun for the polytropic index n = 3 are derived. The result shows clearly that the periodic perturbation effects are the orbital elements of all and the secular perturbation effects are the variation of the longitudes of perihelion, the ascending node and the mean anomaly of epoch. Finally, the author applies the obtained theoretical results to a calculation of the variation of orbital elements of four planets. The numerical results are given in Table 1.     

Post-Newtonian gravitational radiation from binary stars

A method is presented for evaluating post-Newtonian orbital corrections to the orbital-period decrease of a relativistic binary, by using previous results on the gravitational-radiation luminosity of a bounded source and the binary's relative motion. The method is based on an energy-balance equation, whose validity to post-Newtonian accuracy is not proved here, but, in view of recent theoretical results on the classical energy-balance equation, seems to be quite reasonable, and, in view of the available observational data, is practically correct. In the case of the binary pulsar PSR 1913 + 16 the proposed relative orbital correction amounts to 10^–6 of the current observational uncertainty, thus greatly favoring the predictions of the classical quadrupole formula.     

Measurement of gravitational spin-orbit coupling in a binary-pulsar system

In relativistic gravity, a spinning pulsar will precess as it orbits a compact companion star. We have measured the effect of such precession on the average shape and polarization of the radiation from PSR B1534+12. We have also detected, with limited precision, special-relativistic aberration of the revolving pulsar beam due to orbital motion. Our observations fix the system geometry, including the misalignment between the spin and orbital angular momenta, and yield a measurement of the precession time scale consistent with the predictions of general relativity.     

Orbit of the spectroscopic binary b Persei

New spectroscopic orbital elements have been derived for the close binary system b Persei. The period is improved to 1.527360 days. Earlier observations by Cannon (1914), Harper (1930) and Heard (1938) have been reanalysed and the reality of the variations in the orbital elements is established. The change inω indicates an aspidal motion period of about 60 years. Changes in some of the orbital elements may be due to the distortion of the radial velocity curve by gas streams present in the system. In view of the flaring radio emission detected from this system and the variations of the orbital elements, we believe that the close binary system b Persei is in an active mass transfer phase.     

Parameter-induced stochastic resonance with a periodic signal

In this paper conventional stochastic resonance (CSR) is realized by adding the noise intensity. This demonstrates that tuning the system parameters with fixed noise can make the noise play a constructive role and realize parameter-induced stochastic resonance (PSR). PSR can be interpreted as changing the intrinsic characteristic of the dynamical system to yield the cooperative effect between the stochastic-subjected nonlinear system and the external periodic force. This can be realized at any noise intensity, which greatly differs from CSR that is realized under the condition of the initial noise intensity not greater than the resonance level. Moreover, it is proved that PSR is different from the optimization of system parameters.     

LMTO能带计算中空原子球和原子空d态的作用

本文研究LMTO能带计算中空原子球和空d态(未填充价电子的d态)的特征和作用。提出一种只在矩阵元计算中计入空d态和空原子球的p、d态的计算方案,在GaAs能带的实际计算中表明,该计算方法把通常求解的36×36阶久期方程减小为10×10阶,仍然得出合理的能带结构,然而,计算效率显著地提高。     

二元合金成份的无标样X光能谱定量分析

一般用电子探针对合金成份进行定量分析时都用标样进行对比。本文提出了一个不用标样的二元合金成份的定量分析方法。利用扫描电子显微镜-X光能谱分析装置同时测定二元合金(Cu-Ga,GaAs)中二元素的K_a光子数比值后,由简化的入射电子能量损失公式和X光激发截面公式并考虑了二次荧光效应后,可计算出二元合金的成份。当入射电子的过电压保持在2—3时,得到和实际成份一致的结果。利用上述简化模型对文献中不同纯元素特征X光的“仪器灵敏度”进行了计算和讨论。 关键词：