固体火箭发动机的加速度效应

本文研究旋转固体火箭发动机在加速度载菏下的性能变化。根据至今己提出的4种重要模式:力学模式、热力学模式、应力模式、气动力学模式,得出了每种模式的简化模型,并附加了一个内弹道计算机程序。分析结果表明,应力模式对圆孔药柱并不重要。其它模式对固体发动机性能都有影响。分析结果与发动机数据比较表明,侵蚀燃烧效应是旋转速度的函数。     

Muscle atrophy associated with microgravity in rat: basic data for countermeasures

Morphological, contractile properties and myosin heavy chain (MHC) composition of rat soleus muscles were studied after 2 weeks of unloading (HS) and after 2 weeks of HS associated with selective deafferentation (HS + DEAF) at the level L4 and L5. The same significant reductions in muscle mass and tetanic tension were found after HS and HS + DEAF. However, the transformation of the slow-twitch soleus muscle towards a faster type characterized by a decrease in twitch time parameters and an increase in fast-twitch type MHC isoforms in HS did not appear in HS + DEAF conditions. Our results also showed that a pattern similar to firing rate of motoneurones innervating slow-twitch muscles inhibited the slow to fast fiber changes observed during HS. Nevertheless, neither the loss of mass or force output in the HS muscles were prevented by electrostimulation. Immobilization in a stretched position during HS maintained the muscle wet weight, mechanical and electrophoretical characteristics close to control values. We concluded that the decrease in mechanical strains imposed on the muscle during unloading was the main factor for the development of atrophy, while the kinetic changes might be predominantly modulated by the nervous command. These basic data suggested that some experimental conditions such as electrostimulation or stretching, could participate in countermeasure programmes.     

改善推进剂老化和低温物理性质的键合剂系统

新的混合键合剂系统用于端羟基聚丁二烯推进剂配方时,推进剂的高温老化特性和低温物理性质都有很大改善。混合键合剂系统由 MT_4[2.0克分子三-1-(2-甲基氮丙啶)膦化氧、0.7克分子已二酸和0.3克分子酒石酸的反应产物]、HX752[双-间苯二酰-1-(2-甲基)氨丙啶]和 BIDE(丁基亚胺二乙醇)组成,其重量百分含量分别占推进剂组成的0.10～0.20%、0.10～0.20%和0.02～0.05%。     

全桥ZVS变换器的一个新系列

本文介绍软开关全桥（FB）脉宽调制（PWM）变换器的一种新系列，它的特征是在宽范围输入电压和输出负载上所有桥开关是零电压开关（ZVS）的，并且具有最小的占空比损耗和环流。ZVS的初级开关采用两个磁性元件来实现，两个桥臂间的相移变化使这两个磁性元件的伏秒积作相反方向的变化。其中一个磁性元件是变压器，而另一个是耦合电感器或是单绕组电感器。采用变压器是提供隔离输出，而电感器用于为ZVS存贮能量。     

The Suess-Urey mission (return of solar matter to Earth)

The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs.     

Influence of graviceptives cues at different level of visual information processing: the effect of prolonged weightlessness

We evaluated the influence of prolonged weightlessness on the performance of visual tasks in the course of the Russian-French missions ANTARES, Post-ANTARES and ALTAIR aboard the MIR station. Eight cosmonauts were subjects in two experiments executed pre-flight, in-flight and post-flight sessions.

In the first experiment, cosmonauts performed a task of symmetry detection in 2-D polygons. The results indicate that this detection is locked in a head retinal reference frame rather than in an environmentally defined one as meridional orientations of symmetry axis (vertical and horizontal) elicited faster response times than oblique ones. However, in weightlessness the saliency of a retinally vertical axis of symmetry is no longer significantly different from an horizontal axis. In the second experiment, cosmonauts performed a mental rotation task in which they judged whether two 3-D objects presented in different orientations were identical. Performance on this task is basically identical in weightlessness and normal gravity.     

The natural cytotoxicity in cosmonauts on board space stations

The nature of the changes of resistance to infection seems to be very important. Our studies indicate that different functions of natural killers could be depressed after the spaceflight. The decrease of the percentage of the lymphocytes that can bind target cells lead to the lowering of the “active” NK level and this can be resulted in the depression of total NK activity and lowering of resistance to viral and tumor antigens. The investigation of natural killer cells in cosmonauts before and after short and long-term spaceflights also revealed the important role of spaceflight duration, stress and individual immune reactivity.     

遥测处理器和图形记录器之间的通用接口

在遥测领域通常使用的图形记录器都经由一系列数一模转换器系统连于遥测处理器上，一种新的模块结构系统直接从处理器广播总线接收数据，并将其分配给１０台数字式图形记录器，该接口由计算机编程，为每个显示通道指定独特的标记，该系统省去ＤＡＣｓ和接插板，它简化了显示系统的工作，加速了从试验到试验的过渡过程并减少了维修费用。     

0.1deg／h DSP控制的光纤陀螺仪

本文叙述了仅由一个高速数字信号处理器（ＤＳＰ）控制的０．１ｄｅｇ／ｈ的光纤陀螺仪（ＦＯＧ）。所有控制回路的采样时间等于光通过传感环圈的传播时间。该装置采用了一个５００米长的光纤传感环圈，工作采用闭环模式。控制和补偿算法由软件完成，并且由一个高速ＤＳＰ执行。该处理器通过一个高速同步串行总线维护通讯协议。该单轴ＦＯＧ是按模块化结构设计的，是ＬＦＫ９５系统的一个基本结构单元；ＬＦＫ９５系统是一个商用低成     

振动中的逆问题

本文考虑有限范围内无阻尼弹性系统无限小自由振动问题。述评由一些文献组成。这些文献涉及到从固有频率数据中唯一地重新构造一个振动系统。文献分为两组——一组涉及离散系统,该系统的逆问题与矩阵逆特征值问题紧密相关;另一组则涉及连续系统,该系统由Sturm—Liouville方程组中的某个方程所控制,或者由细梁弯曲振动的Euler—Bernoulli方程控制。