航空发动机燃烧室喷嘴内部燃油结焦研究

对在最严重热负荷时喷嘴内部燃油沉积率以及燃油性能参数的变化进行了试验研究。对1个相似的喷嘴试验件进行了传热试验,通过试验修正计算中关键的传热系数,建立了符合喷嘴实际的传热计算方法;用该方法推算发动机在真实条件下发生最严重热负荷的工况,然后进行了燃油沉积率试验,得到了燃油管道沉积率与温度的关系,同时得到了喷嘴和油滤上积沉的特征;对沉积物成分进行了分析,并测定了燃油油样进行性能参数。通过研究结果,提出了改善喷嘴燃油热安定性的措施。     

差分方程yn+1=A+yn/(kΣi=1αiyn-i)的全局吸引性

研究差分方程yn+1=A+yn/(kΣi=1αiyn-i),N=0,1,...正解的稳定性,其中,A∈(0,∞),αi∈(0,∞),kΣi=1αi=k,k≥1且是整数,初始条件y-k,...,y0为任意正数.阐述并证明该方程的惟一正平衡点是全局吸引子且吸引域取决于方程的系数.     

Progress of super-pressure balloon development: A new “tawara” concept with improved stability

The super-pressure balloon (SPB) has been expected to be a flight vehicle that can provide a long flight duration to science. Since 1997, we have developed the SPB. Now we are at the phase of developing an SPB of a practical size. In 2009, we carried out a test flight of a pumpkin-shaped SPB with a 60,000 m³ volume. The undesirable result of this flight aroused us to resolve the deployment instability of the pumpkin-shaped SPB, which has been known as one of the most challenging issues confronting SPB development. To explore this deployment issue, in 2010, we carried out a series of ground tests. From results of these tests, we found that an SPB design modified from pumpkin, named “tawara”, can be a good candidate to greatly improve the deployment stability of the lobed SPB.     

调相白噪声对频率传递短期稳定度的影响分析

详细分析了调相白噪声对频率稳定度的影响。经过理论分析,得出了频率传递系统信噪比的开方与稳定度成正比,调制信号频率与稳定度成正比。经过分析得到,在一定范围内,提高激光器光功率可以提高频标传递的稳定度;调制频率和传递系统信噪比是影响短期稳定度的两个重要因素;通过增加EDFA的方法不能提高传递系统短期稳定度,反而每增加4到5个EDFA,稳定度下降1个数量级。     

多级泵级间导叶的优化与数值仿真

级间导叶是多级离心泵的重要组成部件,对泵性能有重要影响。基于国内外研究提出了级间导叶的四种设计方法,分别为改进径向式导叶设计法、四条流线包围流道设计法、中间流线矩形扫描法和中间流线圆形扫描法。为某多级液氢泵分别设计一种径向式导叶和四种流道式导叶,验证了设计方法的可行性。对径向式导叶及四种流道式导叶进行了数值仿真研究,结...     

直升机低速飞行特性与意外右偏航

根据国外有关参考资料，对直升机丧尾桨推力导致意想不右偏航进行了讨论分析，简单介绍了直升机飞行时的四种飞行特性，（风标稳定性、尾桨涡环状态、主旋翼桨盘旋涡影响，丧失前飞升力）在意外右偏航中的作用和特点，以及改出方法和实施改出的应急措施，为飞行人员保证飞行安全提供了参考依据。     

The Special Purpose Dexterous Manipulator (SPDM) Systems Engineering Effort – A successful exercise in cheaper,faster and (hopefully) better systems engineering

The Special Purpose Dexterous Manipulator (SPDM) is the latest Space Robot developed by the Canadian Space Agency (CSA) and McDonald Detwiller Space and Advanced Robotics (MD Robotics, previously Spar Aerospace) for the International Space Station (ISS). The SPDM has presented its designers with a number of new challenges in performing the Systems Engineering effort required for a complex robotic system:(1) The SPDM initial design was started and attained various levels of maturity for various components under the Space Station Freedom environment, then the Program was stopped and finally restarted under the harsher environment in which the International Space Station is being built.(2) The SPDM is the first space robot to utilize previously developed and space certified robotic components, as well as components with high-commonality to the previously developed ones (electronics, S/W).(3) New requirements levied by the Customer during the negotiations leading to the Program re-start necessitated significant architectural changes versus the SPDM configuration `frozen' when the Program was shut down.(4) The SPDM is the first robotic system of this complexity that is being built under a Firm Fixed Price contract, with the commonality assumptions as one of the cost drivers.This combination of components of various pedigree, coupled with the constraints imposed by an FFP contract have been addressed by the designers through the definition of a novel approach to integrated Systems and Design Engineering.     

高稳定正弦交流稳流源的研究

为了对电能进行高准确度的测量，需要有高稳定的电源装置，稳定交流电源可采用负反馈控制系统，但易产生自激。如在反馈系统中加入一含有延时环节的负反馈，可以解决系统闭环稳定性与开环增益之间的矛盾。     

轰炸机的发展历程和前景

介绍了轰炸机在各历史阶段发挥的重要作用，分析了轰炸机从诞生到第二次世界大战中发展成熟，以及在冷战时期轰炸机发展的3个阶段。描述了在每个时期不同战场环境下对轰炸机的不同要求，以及由此而产生不同的气动布局形式，进而分析了未来轰炸机发展的3个方向和美国当前可能的型号选择。     

由稳态飞行确定纵向气动导数

研究了从稳态对称飞行数据估计气动导数的一种方法，要估计的导数是纵向静稳定性和操纵性导数，尾翼产生的阻尼导数、速度对升力和俯仰力矩系数影响的导数，其方法是基于扩展的纵向静稳定性和操纵性理论以及相应的飞行试验数据表示方法，对于大多数气导数，假设飞行测量数据是以平衡曲线和ＣＬ（α）曲线形式给出的，导数估计表达式是由已知常数，直接或非直接测量量的代数关系式构成，估计精度用结果标准误差或系统误差带表示。所研