The Transition Between Fast and Slow Solar Wind from Composition Data

The transition between coronal hole associated fast solar wind and slow solar wind is studied using data from the high resolution mass spectrometer SWICS on ACE. We discuss the data in the framework of a recent theory about the global heliospheric magnetic field and conclude that the data are consistent with magnetic connections between field-lines in the fast and in the slow wind. This revised version was published online in June 2006 with corrections to the Cover Date.     

Exploring The Saturn System In The Thermal Infrared: The Composite Infrared Spectrometer

The Composite Infrared Spectrometer (CIRS) is a remote-sensing Fourier Transform Spectrometer (FTS) on the Cassini orbiter that measures thermal radiation over two decades in wavenumber, from 10 to 1400 cm^{− 1} (1 mm to 7μ m), with a spectral resolution that can be set from 0.5 to 15.5 cm^{− 1}. The far infrared portion of the spectrum (10–600 cm^{− 1}) is measured with a polarizing interferometer having thermopile detectors with a common 4-mrad field of view (FOV). The middle infrared portion is measured with a traditional Michelson interferometer having two focal planes (600–1100 cm^{− 1}, 1100–1400 cm^{− 1}). Each focal plane is composed of a 1× 10 array of HgCdTe detectors, each detector having a 0.3-mrad FOV. CIRS observations will provide three-dimensional maps of temperature, gas composition, and aerosols/condensates of the atmospheres of Titan and Saturn with good vertical and horizontal resolution, from deep in their tropospheres to high in their mesospheres. CIRS’s ability to observe atmospheres in the limb-viewing mode (in addition to nadir) offers the opportunity to provide accurate and highly resolved vertical profiles of these atmospheric variables. The ability to observe with high-spectral resolution should facilitate the identification of new constituents. CIRS will also map the thermal and compositional properties of the surfaces of Saturn’s icy satellites. It will similarly map Saturn’s rings, characterizing their dynamical and spatial structure and constraining theories of their formation and evolution. The combination of broad spectral range, programmable spectral resolution, the small detector fields of view, and an orbiting spacecraft platform will allow CIRS to observe the Saturnian system in the thermal infrared at a level of detail not previously achieved.This revised version was published online in July 2005 with a corrected cover date.     

DD402单晶合金在小发涡轮工作叶片上的应用

论述了所研制DD402单晶合金的化学成分、显微组织、热处理及长期组织稳定性、物理性能、力学性能、化学性能等。通过考核试车和试飞证明，用该合金制造的小型航空发动机涡轮工作叶片工作正常。这一成果可供航空发动机设计人员和工艺人员在新机研制和生产中借鉴。     

一种扩展了价格信息的进程代数

针对目前进程代数缺乏成本建模和分析能力的现状,提出一种扩展了价格信息的进程代数(Price process algebra,PPA).在传值通信系统演算(Calculus of communication systems,CCS)基础上为进程动作和状态扩展价格函数,使用价格迁移系统给出PPA的语义,证明PPA的进程状态扩展累计成本的合理性和完备性,给出构造状态空间的算法并证明该算法的有效性,实例分析说明PPA用于成本建模和分析的可行性.     

电火花表面强化TC4 钛合金的组织与性能

以石墨为电极,分别在煤油和雾介质中对TC4钛合金(表面分别未涂覆及涂覆碳层)进行电火花表面强化.对强化层微观组织、相组成及显微硬度进行了研究.结果表明,所有强化层组织均呈菊花瓣状.合金表面涂覆碳层后强化层表面球状碳化物数量都较未涂覆时明显增加,且在煤油介质中得到的强化层中碳化物在花瓣边缘处聚集,雾介质条件下碳化物分布更为弥散、均匀.对强化层进行物相分析表明,强化相由电极C和基体Ti原位反应生成,强化层由基体α-Ti和TiC相组成.强化层表面显微硬度较原始TC4钛合金相比大幅提高,雾介质中得到的强化层显微硬度值与煤油介质中基本相同,可达800 MPa左右,但分布更为均匀,力学性能更稳定.     

深空探测中的激光诱导击穿光谱探测仪

物质成分探测是深空探测领域非常重要的技术领域,激光诱导击穿光谱技术是一种可以非接触式快速获得物质元素成分信息的手段,论文针对2020年我国首次火星探测任务提出的火星表面成分探测仪,阐述了激光诱导击穿光谱技术基本原理,国内外的技术发展现状和趋势,重点围绕火星环境、有效载荷生存性进行了分析,最后论文详细探讨了激光诱导击穿光谱技术中的数据反演和定量化技术。     

The thermospheric composition different responses to geomagnetic storm in the winter and summer hemisphere measured by “SZ” Atmospheric Composition Detectors

Three “SZ” Atmospheric Composition Detectors (ACDs) on board spacecraft “SZ-2”, “SZ-3” and “SZ-4” were launched on 10th January 2001, 26th March 2002 and 31st December 2002 separately. A large quantity of thermospheric composition data at the orbital altitude ranging from 330 to 362 km were collected from the in-situ measurement of ACDs. The spacecrafts’ lifetime was just in the second peak period of the 23rd solar cycle which includes two peaks and the solar activity value F_10.7 was from 89 to 228. During this period, several intense geomagnetic disturbances happened.     

The Mars Environment Analogue Platform long duration balloon flight

The MEAP (Mars Environment Analogue Platform) mission was to fly a stratospheric balloon on a semicircular trajectory around the North Pole in summer 2008. The balloon platform carried the high-resolution neutral gas mass spectrometer P-BACE (Polar Balloon Atmospheric Composition Experiment) as scientific payload. MEAP/P-BACE is a joint project between the Esrange Space Center, Sweden, the University of Bern, Switzerland and the Swedish Institute of Space Physics (IRF), Kiruna, Sweden. Mission objectives were to validate the platform for future long duration flights around the North pole, to validate the P-BACE instrument design for planetary mission applications (conditions in the Earth stratosphere are similar to the conditions at the Mars surface), to study variation of the stratospheric composition during the flight and to gain experience in balloon based mass spectrometry. All objectives were fulfilled.     

推进剂组分对固体燃料冲压发动机性能的影响

为研究不同组分推进剂对固体燃料冲压发动机(SFRJ)燃烧性能的影响,以添加了石蜡、炭黑以及炭纤维的聚乙烯(PE)为推进剂,采用连管点火实验装置对SFRJ进行了研究。用扫描电镜观测了燃烧后的燃面形貌。用三维扫描仪和数据重构方法获得了燃速三维分布。根据实验所获数据进一步计算得到不同工况下SFRJ工作性能参数。结果表明:加入5%的炭纤维会阻碍聚乙烯基推进剂燃烧表面的机械剥蚀,影响热解过程,使其无法自持燃烧。通过燃速三维分布发现了开尔文-亥姆霍兹不稳定现象。在聚乙烯基推进剂中添加炭黑和石蜡均能够提高燃速,石蜡影响更明显。石蜡质量分数为30%、50%以及纯石蜡的推进剂比聚乙烯分别提高了375%、514%和544%。最后拟合得到了聚乙烯基推进剂平均燃速与石蜡质量分数呈指数递增关系。     

The X-Ray Spectrometer on the MESSENGER Spacecraft

NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) mission will further the understanding of the formation of the planets by examining the least studied of the terrestrial planets, Mercury. During the one-year orbital phase (beginning in 2011) and three earlier flybys (2008 and 2009), the X-Ray Spectrometer (XRS) onboard the MESSENGER spacecraft will measure the surface elemental composition. XRS will measure the characteristic X-ray emissions induced on the surface of Mercury by the incident solar flux. The Kα lines for the elements Mg, Al, Si, S, Ca, Ti, and Fe will be detected. The 12° field-of-view of the instrument will allow a spatial resolution that ranges from 42 km at periapsis to 3200 km at apoapsis due to the spacecraft’s highly elliptical orbit. XRS will provide elemental composition measurements covering the majority of Mercury’s surface, as well as potential high-spatial-resolution measurements of features of interest. This paper summarizes XRS’s science objectives, technical design, calibration, and mission observation strategy.