运算放大器电路非线性失真的Volterra泛函分析

本文给出了运算放大器的非线性分析模型。提出了由运算放大器摆率非线性和有限增益特性引起的谐波失真和互调制失真等分析的Volterra泛函级数法,它是一种完全解折的频域中的符号法;同时,本文还提出了改进的线性传递函数和非线性传递函数的灵敏度及n阶非线性另灵敏度等新慨念。最后给出了关于改进运放电路设计准则的n点建议。     

Artificial gravity: a possible countermeasure for post-flight orthostatic intolerance

Four payload crewmembers were exposed to sustained linear acceleration in a centrifuge during the Neurolab (STS-90) flight. In contrast to previous studies, otolith–ocular reflexes were preserved during and after flight. This raised the possibility that artificial gravity may have acted as a countermeasure to the deconditioning of otolith–ocular reflexes. None of the astronauts who were centrifuged had orthostatic intolerance when tested with head-up passive tilt after flight. Thus, centrifugation may also have helped maintain post-flight hemodynamic responses to orthostasis by preserving the gain of the otolith–sympathetic reflex. A comparison with two fellow Neurolab orbiter crewmembers not exposed to artificial gravity provided some support for this hypothesis. One of the two had hemodynamic changes in response to post-flight tilt similar to orthostatically intolerant subjects from previous missions. More data is necessary to evaluate this hypothesis, but if it were proven correct, in-flight short-radius centrifugation may help counteract orthostatic intolerance after space flight.     

COSAC onboard Rosetta: a bioastronomy experiment for the short-period comet 67P/Churyumov-Gerasimenko

The COSAC (Cometary Sampling and Composition Experiment) onboard the Rosetta mission is a combined gas chromatograph (GC)-mass spectrometer (MS). It is situated on Philae, the lander of the mission, which is intended to land on the nucleus of comet 67P/Churyumov- Gerasimenko. The purpose of the experiment is to analyze the volatile fraction of soil samples retrieved by a drill. For investigation, the samples will be pyrolysed, and the emanating gases fed into a GC, into an MS, or the combination of both. In the first part of this paper, the bioastronomical relevance of such measurements is outlined. In the second part the details of the hardware and its performance are described.     

海湾战争与美国E—3预警机

海湾战争中,美国E-3预警机战功显赫。本文详述E-3预警机研制过程,基本规格,目前生产型号,航空电子装备,以及未来的技术改造。     

疾风劲草,板荡诚臣——为张处弘鼓与呼

唐李世民《赐萧瑀》一诗中说:“疾风知劲草,板荡识诚臣。勇夫安识义?智者必怀仁。”前两句是说在严峻时势的考验下,才能识别忠良。“板荡”系指《诗·大雅》中的《板》、《荡》两诗,反映周厉王时期动荡、艰难的社会情况,后遂以“板荡”比喻艰难动荡之世。张处弘——中国航空史研究会副理事长,浙江航空学会前理事长、杭州蓝天飞艇技术研究所所长,是疾风中的“劲草”,艰辛中的“诚臣”,不是李世民诗句中所说的徒有一时之勇的勇夫,而是中国航空战线上的真正勇士,航空科技事业的智者！张处弘同志在空军工作多年,离开部队时本可以以相当高的级别安享晚年,但他却一心扑向了研制飞艇的事业,靠自己的力量办起了民办航空研究所,并完全凭自己的努力,历尽千难万苦,中国人自己研制的载人飞艇获得成功。正当张处弘的飞艇事业向更大的成     

FL—1风洞攻角控制系统设计

本文介绍了ＦＬ－１风洞攻角（飞机模型的俯卸角）控制系统的理件和软件配置，介绍了ＰＣ机在工业控制系统中的应用。叙述了把十四位并行二进制码实时转换成攻角（度）的方法，以及在ＰＣ机上用高级语言编写的主程序调用汇编语言编写的子程序的方法。     

返回式卫星数字姿态控制系统及飞行试验结果

简要介绍我国返回式卫星上用的计算机数字姿态控制系统的方案;重点阐述姿态确定和相平面控制律的设计方法;最后简述飞行试验的结果。     

冷轧无间隙原子钢中的微带生成机理

分析了冷轧体心立方金属中微带的形成原因.基于塑性变形理论,运用Taylor模型和Bishop＆Hill最大功原理,计算了变形体心立方晶体中滑移系上的切应变分布.计算结果表明,冷轧时当晶粒的轧向平行于晶粒的某些特定取向时,大量的局部切应变将集中产生在一个滑移面上并在此形成微带.这一高度局域性的切应变是形成剪切带的原因.此时,剪切带与轧制方向之间夹角为30°.另外,微带呈片状是双交滑移的结果,透射电子显微镜观察到的剪切带所在晶粒的取向和所在滑移面证实了这一微带的形成机制.