范德蒙行列式应用三则

本文介绍了如何构造范德蒙行列式进行行列式计算及证明的三个应用问题。     

关于八元数行列式的一种定义方法

论文通过对八元数的研究,给出八元数行列式的一种定义方法,并使八元数自共轭矩阵的行列式必为实数．     

广义矩阵函数的一个注记

设f∈FSn 广义矩阵函数df:Fn×n→F定义为df(A) =∑σ∈Snf(σ)∏ni =1 aiσ(i) .论文刻划了广义矩阵函数和行列式的内在联系 ,改进了已有的相应结果     

次正定矩阵和次亚正定矩阵行列式的不等式

论文提出了k-局部次完全对称矩阵的概念，研究了次正定矩阵和次亚正定矩阵行列式的不等式，对现有的一些结果作进一步的推广。     

考虑前屈曲几何非线性影响的结构稳定性分析

本文采用有限元法分析考虑前屈曲几何非线性影响的结构稳定性。应用伴有线性搜索和各种牛顿型解法的组合弧长法可以顺利地描述包含有极值点的载荷一位移曲线,与此同时,若在加载点处计算结构刚度矩阵的行列式值、临界载荷因子和特性刚度参数等值,则可根据稳定准则,通过插值确定临界点的位置。从而为研究复杂结构稳定性提供简便而有效的方法。     

运用拓扑方法求取网络传递函数

运用拓扑方法求解校正网络的传递函数,它可直接到写出传递函数分子和分母各项,而不是像过去常用克希荷夫定律求解行列式各项。后者的缺点是要对0项的运算和对对消项的运算。特别是对于复杂的校正网络,主要的计算工作量是对0项和对消项的计算,不仅浪费机时,也降低了计算精度。应用拓扑方法求解校正网络的传递函数就能避免上述缺点。因而它得到越来越广泛的应用。     

用三轴转台辨识陀螺仪误差模型系数时的速率试验设计

介绍了用三轴转台的匀角速率功能标定捷联陀螺仪的动态误差模型系数的方法。首先计算了陀螺仪的输出，陀螺仪的误差模型系数以及三轴转台三轴同时施加的角速率的函数关系。其次在给定不同的中、内环角速率比时，用傅立叶分析的方法得出了陀螺仪输出的各次谐波幅值与动态误差模型系数的关系，以及相应的结构矩阵和信息矩阵。最后根据信息矩阵行列式值与外环角速率的关系，选定了标定陀螺仪动态误差模型系数时的最优三轴速率试验计划。     

一种应用于二维DG方法的次优策略

构建了最高达10次的二维Serendipity间断有限单元,作为二维节点型DG方法的次优应用策略。通过强制边界节点为勒让德-高斯-勒巴图积分点,保证了良好的边界插值特性。该种新构建方法使得单元内点通过最大化范德蒙行列式的绝对值确定,并得到了带约束非线性优化问题的全局收敛解。最终得到的节点分布具有特定的对称构型,单元的勒贝格常数较低,介于所见文献的其他类节点单元之间,表明可以作为插值单元进行计算。与紧致型节点单元相比,构建得到的单元节点数量仅比完备插值空间所要求的紧致节点数量多2个节点,成为一种次优应用策略。此外,相比于传统的张量积型节点单元,极大的节省了计算资源,更适宜在间断有限元类方法中应用。     

基于Web的拦截网页中弹出广告编程技术的研究及实践

本文采用基于Web的拦截技术,通过对服务器传来的数据包进行分析,对其中的弹出广告的数据包进行过滤,最终实现拦截网页中弹出的广告牌,达到快速浏览网页的效果。     

The concept of a Space-Space interferometer for observations in mm and sub-mm wavebands

At present, space radio astronomers and engineers study the prospects of design of the second-generation ground-space interferometers for astrophysical research with the microsecond angular resolution of sources. The implemented Japanese VSOP project (1998–2003) and the Russian Radioastron project (under preparation for space flight) are related to the first generation. In this paper, the ideology and configuration of the Space-Space interferometer are considered. It would allow one to obtain principally new capabilities: to exclude the Earth’s atmosphere influence, to realize a quasi-phase-stable interferometer, and to remove the problems of electromagnetic compatibility with other services. Moreover, a capability will appear to carry out preliminary correlation processing onboard the spacecraft due to achievement of small residual uncertainties in signal delay and frequency and, owing to this, to realize onboard data compression in order to transmit data to the Earth by usual space communication channel.     

Soyuz in French Guiana: A strategic perspective

After a proposition from Russia to France, ESA agreed to see Soyuz rockets take off from French Guiana. From industry, to governments and agencies, many Russian and European actors were involved in this project and they all had different motives. It is therefore relevant to try to discern them so as to understand the rationale behind this cooperative endeavor. Soyuz's primary role is to consolidate Arianespace commercial position in the launching market and to bring activity and founding to a stagnating Russian space sector. With this decision Arianespace will have a full range of commercially available launchers with Soyuz completing the two European rockets Vega and Ariane V. But since Vega and Ariane must have the priority, there is a risk to see an insufficient launch rate for Soyuz, which would not satisfy the Russian partners. Commercial elements alone cannot justify the agreement. There is a larger strategic ambition behind. What is at stake is the future development of innovative launch systems. It is important for ESA to maintain an autonomous access to space and to maintain a dynamic and strong European propulsion industry. Cooperation with Russia can offer an increase of expandable rockets capabilities and can pave for the next generation of launch vehicles. Moreover, we can detect an interest in acquiring a system that has the potential for human space flight capacity. Finally, the decision to launch Soyuz from French Guiana was the conjunction of Russian and French national interests, which led to a complete redefinition of the relations between Europe and Russia. It is of strategic importance that we, Europeans, adapt to this evolution and understand the new place that Russia takes in our space sector.     

Bubble detector characterization for space radiation

In light of the importance of the neutron contribution to the dose equivalent received by space workers in the near-Earth radiation environment, there is an increasing need for a personal dosimeter that is passive in nature and able to respond to this neutron field in real time. Recent Canadian technology has led to the development of a bubble detector, which is sensitive to neutrons, but insensitive to low linear energy transfer (LET) radiation. By changing the composition of the bubble detector fluid (or “superheat”), the detectors can be fabricated to respond to different types of radiation. This paper describes a preliminary ground-based research effort to better characterize the bubble detectors of different compositions at various charged-particle accelerator facilities, which are capable of simulating the space radiation field.     

浅谈发挥低年级学生学习英语的积极性

英语教学，特别是低年级英语教学既需要教师的积极性，更需要学生的积极性，二者缺一不可。要想发挥学生的学习积极性，首先应发挥英语自身的魅力，启发学生的积极性；其次，以情感促教学调动学生的积极性；再者，采取有效措施巩固学生的积极性。     

The regulatory challenges of ensuring commercial human spaceflight safety

Space tourism is the term commonly used to refer to ordinary members of the public buying tickets to travel to space and back, but has recently become more broadly associated with “any commercial activity offering customers direct or indirect experience with space travel”. The nascent commercial human spaceflight market presents a challenge to regulators with regard to the potential certification and licensing of the flight vehicles and their use (both within and outside the atmosphere), from the perspective of the operator, the flight participants, and third parties who might be affected by the operations. The UK is currently reviewing the issues posed by this emerging sector and its licensing/certification authorities are considering how best to balance their statutory responsibilities with the need to facilitate the development of this new industry and the favour positioning of UK players, eliminating unnecessary regulatory barriers to participation.     

Investigation of phase transition-based tethered systems for small body sample capture

This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and possible return to Earth. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing material equilibrium phases, is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan.     

构建廊坊市政府新型服务管理体系——知识管理

本文试着以廊坊市政府知识管理体系建设为切入点,作为打开市政府知识管理大门的钥匙,在发展完善知识管理理论体系、开拓知识库应用领域的同时,对促进政府适应知识经济发展、向知识型政府转变有一定的启发和指导作用。     

Ground assisted rendezvous with geosynchronous satellites for the disposal of space debris by means of Earth-oriented tethers

Previous studies have shown that extended length Earth-oriented tethers in the geosynchronous (GEO) region can be used to re-orbit satellites to disposal orbits. One such approach involves the extension of a GEO based tether, collection of a debris object, and retraction of the tether, which transfers the retracted configuration to a higher energy orbit for debris disposal. The re-extension of the tether after debris disposal returns the configuration to the near-GEO altitude. The practical feasibility of such a system depends on the ability to collect GEO debris objects, attach them to a deployed tether system, and retract the tethers for transfer to the disposal orbits.This study addresses the collection and delivery of debris objects to the deployed tether system in GEO. The investigation considers the number, type and the characteristics of the debris objects as well as the collection tug that can be ground controlled to detect, rendezvous and dock with the debris objects for their delivery to the tethers system.A total of more than 400 objects are in drift orbits crossing all longitudes either below or above the geostationary radius. More than 130 objects are also known to librate around the stable points in GEO with periods of libration up to five or more years. A characterization of the position and velocity of the debris objects relative to the collection tug is investigated. Typical rendezvous performance requirements for uncooperative GEO satellites are examined, and the similarities with other approaches such as the ESA's CX-OLEV commercial mission proposal to extend the life of geostationary telecommunication satellites are noted.     

Adverse effects of microgravity on the magnetotactic bacterium Magnetospirillum magnetotacticum.

Bacteria that contain magnetosomes display magnetotaxis and align themselves to the earth's magnetic field. When magnetotactic bacteria were first isolated several decades ago it was presumed that geomagnetic orientation allowed magnetotactic bacteria to orient themselves downward towards sediments where the habitat is favorable to their growth and metabolism. As more species of magnetotactic bacteria have been isolated and studied, differences in magnetotactic responses have been observed which suggested that the primary role of magnetosomes might simply be to enhance a microorganism's response to gravity. To resolve if gravity influences magnetotactic behavior in bacteria, Magnetospirillum magnetotacticum was used to examine magnetotaxis in the absence of gravity. Experiments to compare the orientation of bacteria to north- or south-pole magnets were conducted in normal gravity and in the microgravity environments aboard the Space Shuttle and Space Station MIR. In each of the microgravity situations studied, bacteria were impaired in their ability to orient to magnets and the failure to exhibit magnetotaxis appeared to be a function of the loss of magnetosomes. The disappearance of aggregated magnetosomes seemed to correlate with a general loss of cellular integrity in microgravity.