镀膜光纤声相位调制器的研究

本文主要讨论氧化锌镀膜光纤光相位调制器。首先介绍了氧化锌镀膜光纤的几何结构,然后分析了此几何结构压电声光振荡的基本原理并推出了氧化锌镀膜光纤声光相位调制器Ｔ型网络的等效电路模型,最后给出了氧化锌镀膜光纤声光相位调制器的实验测试装置及基本工程原理。     

亚太地区的空间技术合作与应用

亚太地区的空间技术合作与应用陈述彭，励惠国Ａｂｓｔｒａｃｔ：Ａｌｏｎｇｗｉｔｈｔｈｅｐｏｌｙｃｅｎｔｒａｌｉｚａｔｉｏｎｏｆｉｎｔｅｒｎａｔｉｏｎａｌｅｃｏｎｏｍｙａｎｄｒｅｇｉｏｎａｌｒｅａｌｉｇｎｍｅｎｔ，ｔｈｅＡｓｉａ－Ｐａｃｉｆｉｃｅｃｏｎｏ...     

喷丸强化在四梁上的应用与试验

通过喷丸强化在机翼四梁上的应用,作了大量分析和试验验证工作,最后为歼×机翼四梁的喷丸强化提供了可靠的数据,使四梁的疲劳寿命达到了设计要求,并探索了四梁喷丸强化工艺的全过程,也为服役飞机四梁的大修提供了可贵的经验。     

国际空间站上的固定与机动问题

引言。国际空间站，这个位于地球轨道上的空间实验室，给人体工程学专家提出了许多设计上的挑战，同时也为航天员们提出了许多非同寻常和艰难的任务。     

RD2—3型蠕变试验机自动平衡故障调整

介绍怎样正确的调整失平以及围绕失平所产生的故障。     

弹跳膜片设计

弹跳膜片产生已有半个多世纪，但国内成功运用至今也不多见。本文较详细介绍了弹跳膜片特征、理论计算、设计和工艺方法，对如何在设计和工艺上提高弹跳膜片特性的稳定性，如何在信号器的结构设计上以弹跳膜片作为基础元件，采用弹性系统设计，保持弹性系统仍具有弹跳特征，从而克服单个弹跳膜片特性分散、测量精度不高等方面缺陷，提高测量精度和可靠性作了较系统的探讨。     

采用自适应滤波技术的机载雷达跟踪系统

 一、引言 机载雷达跟踪系统的基本功能是提供我机与目标间相对距离矢量有关变量的估值,并保持系统跟踪能力的最佳化。机载大控系统则利用这些估值来形成武器的制导指令,进而完成对目标的截击任务。 过去,机载雷达跟踪系统的设计采用经典伺服机构理论。为了提高系统的跟踪精度,     

Common freshwater cyanobacteria grow in 100% CO2

Cyanobacteria and similar organisms produced most of the oxygen found in Earth's atmosphere, which implies that early photosynthetic organisms would have lived in an atmosphere that was rich in CO2 and poor in O2. We investigated the tolerance of several cyanobacteria to very high (>20 kPa) concentrations of atmospheric CO2. Cultures of Synechococcus PCC7942, Synechocystis PCC7942, Plectonema boryanum, and Anabaena sp. were grown in liquid culture sparged with CO2-enriched air. All four strains grew when transferred from ambient CO2 to 20 kPa partial pressure of CO2 (pCO2), but none of them tolerated direct transfer to 40 kPa pCO2. Synechococcus and Anabaena survived 101 kPa (100%) pCO2 when pressure was gradually increased by 15 kPa per day, and Plectonema actively grew under these conditions. All four strains grew in an anoxic atmosphere of 5 kPa pCO2 in N2. Strains that were sensitive to high CO2 were also sensitive to low initial pH (pH 5-6). However, low pH in itself was not sufficient to prevent growth. Although mechanisms of damage and survival are still under investigation, we have shown that modern cyanobacteria can survive under Earth's primordial conditions and that cyanobacteria-like organisms could have flourished under conditions on early Mars, which probably had an atmosphere similar to early Earth's.