ESA's Biopan 1--"Vitamin" experiment preliminary results

The purpose of “Vitamin” experiment is to study the efficiency of protective substances on three biological acellular systems aqueous solutions exposed to cosmic radiation in space. The first system “LDL”is a low density lipoprotein. The second is “E2-TeBG complexe” in which estradiol (E2) is bound to its plasmatic carrier protein, testosterone-estradiol binding globulin (TeBG). The third is “pBR 322”, a plasmid. “Vitamin” experiment was accomodated in the Biopan which had been mounted on the outer surface of a Foton retrievable satellite. The experiment was exposed to space environment during 15 days. A stable temperature of about 20 °C was maintained throughout the flight. “Vitamin” experiment preliminary results are presented and discussed.     

新型计算机系统对计算结构力学的影响

在过去的20年中,计算机已有了爆炸性的增长,在下一个10年中,由于新型计算机结构和智能计算机的出现预期要增长得更快.下述的计算机硬/软件技术的进展会对结构力学产生很大的影响.     

Leadership issues with multicultural crews on the international space station: lessons learned from Shuttle/Mir

In isolated and confined environments, two important leadership roles have been identified: the task/instrumental role (which focuses on work goals and operational needs), and the supportive/expressive role (which focuses on morale goals and emotional needs). On the International Space Station, the mission commander should be familiar with both of these aspects of leadership. In previous research involving a 135-day Mir space station simulation in Moscow and a series of on-orbit Mir space station missions during the Shuttle/Mir program, both these leadership roles were studied. In new analyses of the Shuttle/Mir data, we found that for crewmembers, the supportive role of the commander (but not the task role) related positively with crew cohesion. For mission control personnel on the ground, both the task and supportive roles of their leader were related positively to mission control cohesion. The implications of these findings are discussed in terms of leadership on board the International Space Station.     

下视搜索状态机载MPRF雷达的地杂波模型

中脉冲重复频率雷达工作在空－空下视状态时地杂波对其性能影响极强。从天线主波束和旁瓣上收到的杂波回波会增加虚警数。     

纹波电流对消电路

纹波电流对消技术将等于或相反的正常变换器纹波电流的AC电流注入变换器输出电压母线。理想的输出纹波电流为零，结果能产生超低噪声变换器输出电压。电路几乎不需要其他元件，也不需要有源电路。只需附加一个滤波感应绕组、一个辅助电感器和一个小电容器。电路把改进型滤波电感器的泄漏电感用作全部或一部分所要求的辅助电感。纹波对消与转换频率、占空比和其他变换器参数无关。电路消除了连续传导模式和断续传导模式时的纹波电流。试验结果表明，纹波电流值降低了80X以上。     

采用ZCS辅助电路的ZVT BOOST变换器

文章提出了一种采用零电流开关（ZCS）作辅助开关而主开关为零电压转换（ZVT）的软开关BOOST变换器；介绍并分析了变换器的工作区间；讨论了设计思路；演示了一个采用绝缘栅双极晶体管（IGBT）的600W10KHz380V输出、交流-直流的BOOST变换器构成的功率因素校正器所获得的实验结果的设计例子。结果表明，在整个规定的线路和负载条件下，辅助开关维持ZCS的同时主开关保持ZVT。     

Changes in chromatin and nucleic acids in rat tissues after two-week spaceflight

The quantitative changes in nucleic acids and chromatin breakdown were followed in blood, thymus and spleen in rats after 14 day flights on board the biosatellites Cosmos-1887 and Cosmos-2044. Quantitative nucleic acid changes within 8-11 h after landing were only mild, most statistically non-significant. An analysis at 48 h after landing showed a marked decrease in a total content of DNA and RNA in spleen and thymus. Within 8-11 h after landing, the symptoms of chromatin breakdown were found as is seen in an increased concentration of its fragments-polydeoxyribonucleotides. The obtained results show that a partial adaptation to microgravity occurs up to flight day 14 in lymphoid organs. Adaptation is accompanied with a reappearing of the sensitive cells. Their chromatin breaks down, then, in a final phase of flight due to hypergravity stress manifesting itself by a temporary increase in polydeoxyribonucleotide concentration several hours after landing. The results are discussed in relation to the changes in chosen parameters after shorter or more prolonged flights.     

一种机载监视雷达演示验证样机

信号处理技术的进步使雷达设计师更有可能开发复杂的探测与成像算法。然而，许多现有的监视雷达系统的设计缺陷却造成了即使仅对算法做小的变化也需要对雷达硬件进行费钱费时的改动这样一种局面。因此，在设计将来的雷达系统时，应采用可编程处理器，具要应用明确定义的接口将处理器与微波硬件隔离开来。本文介绍了我们的一个研究计划的成果，在这项研究计划中，我们通过将现有的在役机载海洋监视雷达与商用计算机工作站和大带宽磁带记录仪关联起来，构成了一个快速原型环境。     

用雷达图像作非协同式空中目标识别：识别率作为信号带宽函数

尽管非协同式目标识别与高可靠敌我识别极其相关，但一直是一个有等解决的问题，过去提出并研究了许多方法，如：利用目标的红外、声学、光学或雷达特征等，其中一些方法是无源法，其优点是不会对被观测目标发出报警，不足之处是观测距离有限，边缘分辨率低，本文介绍的方法是在利用飞机雷达图像的基础上提出的，所研究的是一维雷达图像（通常所说的高距离分辨率剖面图）和二维逆合成孔径雷达（ISAR）图像。