Postmission plasma volume and red-cell mass changes in the crews of the first two Skylab missions

Red-cell mass determinations were performed before and after the first two Skylab missions. The data showed a 14% mean decrease in red-cell mass after the 28-day mission and a 12% mean decrease after the 59-day mission. The red-cell mass returned to premission levels more slowly after the shorter (28-day) than after the longer mission. Plasma volume decreases were found after each mission. with the crew from the longer mission showing the greater change (13% vs. 8.4%). Postmission decreases in red-cell mass and plasma volume have been a general finding in crewmen who return from short or long spaceflight.     

陶瓷隔热瓦表面SiO2-B2O3-MoSi2-SiB4涂层的制备与性能研究

采用料浆涂覆烧结法在高温刚性隔热瓦表面制备了一种新的涂层,并利用X射线衍射仪、X射线光电子能谱仪和扫描电镜对涂层的相组成和微观结构进行了分析,对涂层在波长2.5～20μm范围内不同温度下的辐射率进行了测试。实验结果表明,涂层厚度约为200μm,涂层具有双层结构,中间过渡层为多孔结构,外表面层为致密的玻璃层。在800℃时涂层总的光谱发射率达到0.92。     

C/C复合材料SiC/mullite-Si-Al_2O_3复合涂层微观结构及防氧化性能研究

采用原位生成法在C/C复合材料SiC内涂层表面制备了mullite(莫来石)-Si-Al2 O3抗氧化涂层.采用XRD、SEM分析了涂层的物相组成和微观结构,并测试了SiC/mullite-Si-Al2 O3复合涂层的抗氧化性能.结果表明,外涂层主要由mullite、Si和Al2O3三相组成;涂层致密无裂纹;SiC/mullite-Si-Al2 O3复合涂层在1500℃静态空气中等温氧化75 h后,试样失重仅为4.6%,防氧化性能明显优于单一的SiC内涂层.     

PRSS-1/PakTES-1A Successful Launched by A LM-2C/SMA

正At Beijing time 11:56,on July 9,2018,a LM-2C/SMA launch vehicle was launched successfully sending the PRSS-1 and Pak TES-1A satellites into their designated orbits.This is another significant space program between China and Pakistan after the successful in-orbit delivery of Pak Sat-1R Satellite,marking a     

长三乙火箭将再发外星

２００１年３月２３日，中国长城工业总公司在人民大会堂与欧洲阿斯特里姆公司签订了用长征三号乙火箭，发射国际通信卫星组织亚太地区 ３号卫星暨鑫诺１Ｂ卫星的发射服务合同。这是１９９６年２月１５日长三乙火箭首飞发射国际通信卫星７０８失利以来，该组织与中国航天的首次握手。这表明，凭借自身强劲的发展势头，中国航天又一次赢得了国际宇航界的广泛信任。 根据合同要求，这颗卫星将于２００２年春季发射。星上拥有３０个Ｋｕ波段转发器，发射重量为３２８４千克，卫星设计寿命１２年。该星将定点于东经８５度赤道上空，为中国、俄罗…     

The LM-3B/Yuanzheng 1 Rocket Launch Trajectory

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C/Al2O3型多功能炭/陶复合材料研究

为满足喷管内型面耐烧蚀及背壁绝热的要求,以整体炭毡、炭纤维多维编织件等为预制体,先进行炭素沉积与石墨化,再用Al2O3型高温无机胶进行真空-压力浸渍、烧结,制得C/Al2O3功能型复合材料.对增强相炭纤维与陶瓷相Al2O3的界面结合强度、无机胶液配方改进、提高烧结温度以及用沥青浸渍HIP等方面进行了研究.所获得的复合材料外表面导热系数λ＝0.902W/(m.K)(800℃),内表面线烧蚀率为0.018mm/s,电镜照片显示C/Al2O3的界面结合良好.     

球磨时间对Fe2O3/Al纳米复合材料性能的影响

采用高能球磨法制备了Fe2O3/Al纳米复合粉末,并利用X射线衍射(XRD)、场发射扫描电镜(SEM)以及热分析仪(TGA/DSC)等分析测试手段,系统研究了球磨时间对复合粉末相结构、组织形貌以及热性能的影响。结果表明,随着球磨时间的增加,微米Fe2O3团聚体逐渐进入Al颗粒中,呈均匀弥散分布,且Al晶粒尺寸不断细化。当球磨时间为20 h时,Al粉已均匀分布到微米Fe2O3颗粒表面,球磨引起的晶粒长大与晶粒尺寸减小处于动态平衡,此时铝热反应热焓达到最高。球磨时间大于20 h时,所制备得到的复合粉末热焓反而降低,且易团聚。     

炭/炭/Al2O3陶瓷基复合材料的制备

通过合理的制备工艺制得一种新型既耐烧蚀又能防热的复合材料－炭／炭／ＡＩ２Ｏ３陶瓷基复合材料。预制件整体发毡先通过热梯度气相沉积ＣＶＤ处理,然后经反复的真空－压力浸清ＡＩ２Ｏ３型无机胶,再通过５００℃烧结制得。得到的材料轴向压缩强度大于６０ＭＰＡ。材料外部导热系数为１．７３０Ｗ／（ｍ＾．Ｋ）（８００℃）,内表面线烧蚀率为０．０１２ｍｍ／ｓ。     

Successful Maiden Flight of LM-3C/Yuanzheng 1 Rocket

The LM-3C/Yuanzheng 1 launch vehicle lifted off from the Xichang Satellite Launch Center at 21:52 Beijing time on March 30,2015,putting China’s 17th Bei Dou satellite into orbit.At 03:34 on March 31,the satellite detached from the Yuanzheng 1 upper stage and entered its working orbit directly,marking the success of China’s first launch mission in year 2015.The China Academy of Launch Vehicle     

制备方法对Al/Fe2 O3纳米铝热剂储存性能的影响

利用SEM、XRD和DSC研究了制备方法对Al/Fe2 O3纳米铝热剂储存性能的影响。结果表明,超声共混法制备的纳米铝热剂放置60 d后,活性铝的平均粒径减小4 nm,使得铝热反应放热量降低13%,之后趋于稳定;机械球磨法制备的纳米铝热剂放置7 d后,活性铝平均粒径减小3 nm,120 d之后,缓慢减小至57.8 nm,活性铝的减少使得铝热反应放热量损失高达16%,;溶胶-凝胶法所制备的纳米铝热剂储存120 d后,活性铝平均粒径减小仅1 nm,明显地减缓了纳米铝粉的氧化,放热量损失仅为6%,并保持稳定。     

TD-1HNMR measurements show enantioselective dissociation of ribose and glucose in the presence of H2(17)O

We used Time Domain (1)H Nuclear Magnetic Resonance (NMR) to characterize changes in proton exchange between water and sugar enantiomers at different concentrations of H(2)(17)O (approximately 15-450 mM) and found that dissociation of the (-)-enantiomers of glucose and ribose occurs at significantly higher rates at higher concentrations of H(2)(17)O. The mechanism behind this enantioselective effect is unclear. The hypothesis we propose is that the large magnetic field (B(o) approximately 0.6T) applied during NMR measurements induces electric moments opposite in sign for the D and L-isomers. Because (17)O has a nuclear electric quadrupole moment not = 0, asymmetrically hydrated complexes may form between the B(o)-polarized enantiomers and H(2)(17)O. Either H(2)(17)O is more often hydrating the (+) than the (-)-enantiomers--and consequently pK differences between H(2)(16)O and H(2)(17)O lead to differences in proton exchange between enantiomers and water--or the orientation of H(2)(17)O relative to the B(o)-polarized enantiomers is different, in total or in part, which leads to hydrated complexes with different spatial geometries and different proton exchange properties. This effect is significant for Magneto-Chiral Stereo-Chemistry (MCSC) and astrobiology, and it may help us better understand specific instances of mass independent isotopic fractionation and aid in the development of new technologies for chiral and isotopic separation.     

Twin BeiDou Satellites Launched Atop a LM-3B/Yuanzheng 1

正China launched the 33rd and 34th satellites of the BeiDou navigation system into their preset orbits using a LM-3B/Yuanzheng 1 carrier rocket from the Xichang Satellite Launch Center at 09:48Beijing time on July 29, 2018.This launch was the 5th mission for the global BeiDou system, sending the 9th and 10th satellites into orbits.Through targeted hardware changes and     

LM-3B/Yuanzheng 1 Puts Six BeiDou Satellites into Space

正At 12:23 Beijing time on October 15 and 22:07 Beijing time on September 19, two LM-3B/Yuanzheng 1 launch vehicles lifted off from the Xichang Satellite Launch Center, putting the39th and 40th BeiDou satellites and the 37th and 38th BeiDou satellites of the BeiDou Navigation Satellite System (BDS) into their predetermined orbits respectively. The two pairs of BeiDou satellites are the 13th-16th satellites of the BeiDou global     

Super View-1 03/04 Launched Atop LM-2D

正China launched Super View-1 03/04,a pair of satellites,with a LM-2D carrier rocket from the Taiyuan Satellite Launch Center at 11:24 Beijing time on January 9,2018.The networking operation of 01/02 and 03/04 satellites marks the completion of the first phase of China’s     

环境减灾-1A、1B卫星宽覆盖多光谱CCD相机技术

环境减灾-1A、1B卫星装载的宽覆盖多光谱CCD相机实现了地面像元分辨率优于30m、对地幅宽大于700km、4个谱段推扫成像.CCD相机自2008年9月8日首次开机成像后,不断获取地面可见光信息,图像清晰、层次分明,图像数据广泛应用于灾害监测与评估、灾后恢复重建等方面.文章就HJ-1A、1B卫星CCD相机的设计原理、技术难点、进步点及创新点等进行了总结.     

Chuangxin-1-02 And Shiyan Satellite 3 Launched Atop A LM-2D

A LM-2D launch vehicle blasted off from Jiuquan Satellite Launch Center (JSLC)at 08:15(Beijing time)on November 5,sending Chuangxin-1-02 and Shiyan Satellite 3 into space.According to the data released by the Xi'an Satellite Control Center(XSCC),Chuangxin-1-02 separated from the launch vehicle 856 seconds after the takeoff,and Shiyan Satellite 3 separated from the rocket 63 seconds thereafter.     

热处理对3D-C/PyC/SiC力学性能的影响

研究了2种热处理工艺对3D-C/PyC/SiC力学性能的影响规律和机制。沉积SiC基体前对有PyC界面相的炭纤维编织体进行热处理,使3D-C/PyC/SiC的室温弯曲强度和KIC显著提高,最大提高幅度分别可达38.6%和80.5%。沉积SiC基体后对C/PyC/SiC进行热处理,使3D-C/PyC/SiC的室温弯曲强度和KIC显著降低,最大降低幅度均可达60%以上。     

多星并行测试技术在环境减灾-1A、1B卫星测试中的应用研究

并行测试具有优化测试流程,降低测试成本的优势.文章说明了并行测试技术背景;介绍了实现并行测试的几种拓扑结构;针对环境减灾-1A、1B卫星双星并举的技术特点,对卫星的并行测试技术应用进行了研究,为后续型号提供了经验.     

体道·悟道·得道——《思想道德修养》“2+1”教学模式探讨

《思想道德修养》课程教学研究与改革的目的在于强化育人的主导功能。针对当代大学生的思想特点, 以理论教学与拓展实训有机结合的教学模式,进一步探索思想政治理论课程教改的发展趋势。