Motion of dust in mean motion resonances with planets

Effect of stellar electromagnetic radiation on the motion of spherical dust particle in mean motion orbital resonances with a planet is investigated. Planar circular restricted three-body problem with the Poynting–Robertson (P–R) effect yields monotonic secular evolution of eccentricity when the particle is trapped in the resonance. Planar elliptic restricted three-body problem with the P–R effect enables nonmonotonous secular evolution of eccentricity and the evolution of eccentricity is qualitatively consistent with the published results for the complicated case of interaction of electromagnetic radiation with nonspherical dust grain. Thus, it is sufficient to allow either nonzero eccentricity of the planet or nonsphericity of the grain and the orbital evolutions in the resonances are qualitatively equal for the two cases. This holds both for exterior and interior mean motion orbital resonances. Evolutions of argument of perihelion in the planar circular and elliptical restricted three-body problems are shown. Numerical integrations show that an analytic expression for the secular time derivative of the particle’s argument of perihelion does not exist, if only dependence on semimajor axis, eccentricity and argument of perihelion is admitted. Connection between the shift of perihelion and oscillations in secular eccentricity is presented for the planar elliptic restricted three-body problem with the P–R effect. Period of the oscillations corresponds to the period of one revolution of perihelion. Change of optical properties of the spherical grain with the heliocentric distance is also considered. The change of the optical properties: (i) does not have any significant influence on the secular evolution of eccentricity, (ii) causes that the shift of perihelion is mainly in the same direction/orientation as the particle motion around the Sun. The statements hold both for circular and noncircular planetary orbits.     

The rectilinear three-body problem using symbol sequence II: role of the periodic orbits

We study the change of phase space structure of the rectilinear three-body problem when the mass combination is changed. Generally, periodic orbits bifurcate from the stable Schubart periodic orbit and move radially outward. Among these periodic orbits there are dominant periodic orbits having rotation number (n − 2)/n with n ≥ 3. We find that the number of dominant periodic orbits is two when n is odd and four when n is even. Dominant periodic orbits have large stable regions in and out of the stability region of the Schubart orbit (Schubart region), and so they determine the size of the Schubart region and influence the structure of the Poincaré section out of the Schubart region. Indeed, with the movement of the dominant periodic orbits, part of complicated structure of the Poincaré section follows these orbits. We find stable periodic orbits which do not bifurcate from the Schubart orbit.     

On the restricted circular conservative three-body problem with variable masses

We consider the restricted circular three-body problem in which the main bodies have variable masses but the sum of their masses always remains constant. For this problem, we have obtained the possible regions of motions of the small body and the previously unknown surfaces of minimum energy that bound them using the Jacobi quasi-integral. For constant masses, these surfaces transform into the well-known surfaces of zero velocity. We consider the applications of our results to close binary star systems with conservative mass transfer.     

高压线路雷击故障分析

2007年6月27日上午10：30左右,沧州市出现强雷雨天气过程。沧州供电公司2条高压线路被雷电击断,造成2人死亡的事故。     

谈如何做好数字化地震观测资料的归档与管理工作

地震观测数字化使地震观测资料的载体发生了根本转变。数字化地震观测资料的归档与管理就成为科技档案部门目前急待解决的一个问题,要做好这项工作,就应加强档案法规的宣传力度,建立健全归档管理各项规章制度,确定归档管理运行机制、收集原则、收集范围、分类编号方法、保管、利用等现代管理方法,对数字化地震观测资料进行科学的管理。     

加油站的雷电防护设计

通过对加油站所处环境特点、系统特点中雷电灾害各因素的分析,对加油棚、油罐及附属建筑的直击雷防护和接地,加油站电源、信号系统的雷电系统防护和静电防护等,依据GB 50057、IEC 61312、GB 50156-2002标准对雷电防护的要求,提出了系统的解决方案。     

地震信息服务系统机房接地系统的设计

本文从理论和实践的角度描述了“中国数字地震观测网络”分项信息服务系统中计算机机房接地系统的分类和它们之间的内在关系。提出了在接地系统设计时的具体技术指标。并对计算机机房接地系统设计时应注意的问题提出了一些建议。     

非连续变形分析方法中的阻尼问题研究

定量研究了非连续变形分析(DDA)方法中的黏性阻尼与数值阻尼。首先,基于Newmark直接积分法,推导了块体系统的运动方程。其次,通过动力学中的黏性阻尼理论建立了DDA中动力系数、时间步长与黏性阻尼比的关系式,探讨了DDA中的常加速度积分方案的数值阻尼分区及阻尼比计算方法,进而得到两种阻尼共同作用时的阻尼比表达式,并分析了频域内阻尼比的分布情况。最后,以谐振激励下的块体振动为例,通过对比不同阻尼作用下块体位移的DDA计算值与理论解,验证了本文提出的阻尼比计算公式的正确性。研究表明：黏性阻尼对低频的衰减作用明显,数值阻尼则可以很快地消除高频干扰,而二者共同作用下可降低阻尼的频率相关性。该研究成果为DDA的振动、波动等动力计算的阻尼取值提供了理论依据。     

基于GIS模式的数据仓专题图研究

针对基于GIS的BTEX油气化探数据仓地质专题图制作系统进行研究,分析了基于自动化制图理念的数据流,提出了系统的总体构架及基于国家标准的地质符号库,并根据油田地质成果图规范开发了BTEX油气化探数据仓数据挖掘成果图的制图模板。将该系统应用于渤中凹陷的BTEX数据综合评价图的制作,结果表明该软件具有较好的人机交互性和扩展性,在满足BTEX油气化探数据仓的处理结果专题地图的制作与成果展示的基础上,能够提高BTEX油气化探地质专题图的制图效率。     

地图中艺术性的体现

通过对地图创作中色彩、符号、图面配置艺术手段等的探讨,满足人们对地图的美观要求,更好地体现地图的艺术性。