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131.
航空发动机气态污染物及冒烟的测量 总被引:2,自引:0,他引:2
介绍了新型燃气气态污染物和排气冒烟测量系统的工作过程,对某型航空发动机的气态污染物和排气冒烟进行了测量,分析了样气温度对测量结果精度的影响。 相似文献
132.
从试验手段能力角度引入了可信度的定义,针对可信度改进了贝叶斯算法,同时把试验阶段内所有试验同等对待,推导出了多源数据融合算法,有效解决了大样本验前信息压制小子样现场试验的问题。 相似文献
133.
Electro-hydrostatic actuator (EHA) pumps are usually characterized as high speed and small displacement. The tilting inertia moment on the cylinder block produced by the inertia forces of piston/slipper assemblies cannot be ignored when analyzing the cylinder block balance. A large tilting inertia moment will make the cylinder block tilt away from the valve plate, resulting in severe wear and significantly increased leakage. This paper presents an analytical expression for the tilting inertia moment on the cylinder block by means of vector analysis. In addition, a high-speed test rig was built up, and experiments on an EHA pump prototype were carried out at high speeds of up to 10,000 r/min. The predicted nature of the cylinder block tilt at high speeds corresponds closely to the witness marks on the dismantled EHA pump prototype. It is suggested that more attention should be given to the tilting inertia moment acting on the cylinder block of an EHA pump since both wear and leakage flow between the cylinder block and the valve plate are very much dependent on this tilting moment. 相似文献
134.
基于二项分布的优化截尾序贯检验法能降低平均试验数,可有效用于导弹试验检验方案中,但该方法存在实际风险计算不准确的特点。文章在深入分析该算法基础上,提出采用马尔科夫链的方法计算试验风险,给出了试验方案制定步骤,并用实例计算说明该方法的正确性及可行性。 相似文献
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136.
Akira Fujiwara Naomi Onose Masato Setoh Akiko M. Nakamura Kensuke Hiraoka Sunao Hasegawa Kyoko Okudaira 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The cylindrical column of brittle material processed from soil and rock is a fundamental component of architectures on the surface of solid bodies in the solar system. One of the most hazardous events for the structure is damaging by hypervelocity impacts by meteoroids and debris. In such a background, cylindrical columns made of plaster of Paris and glass-bead-sintered ceramic were impacted by spherical projectiles of nylon, glass, and steel at velocity of about 1–4.5 km/s. Measured crater radii, depth, and excavated mass expressed by a function of the cylinder radius are similar irrespective of the target material, if those parameters are normalized by appropriate parameters of the crater produced on the flat-surface target. The empirical scaling relations of the normalized crater radii and depth are provided. Using them, crater dimensions and excavated mass of crater on cylindrical surface of any radius can be predicted from the existing knowledge of those for flat surface. Recommendation for the minimum diameter of a cylinder so as to resist against a given impact is provided. 相似文献
137.
刘兴富 《航空精密制造技术》2002,38(1):41-44
通过直角坐标系的平移、旋转确定圆弧上点的方法,提出了在万能工具显微镜上利用其有限工作行程,精确绘制半径样板圆弧检测放大图的方法。 相似文献
138.
XY502胶粘剂的测试结果始终处于不稳定状态,通过大量的对比试验与研究,确定出XY502胶粘剂的最佳制样方法:混合甲乙组份2小时,打磨方式达到标准要求,同时在房间里配除湿机来把湿度固定在45%-55%范围内,胶接及停放温度对结果影响很大,必须把胶接及停放温度控制在25℃-30℃之间,这样XY502的测试结果才符合标准,以上方法才是最佳的制样方法。 相似文献
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140.
James D. Walker Christopher J. Freitas Mark B. Tapley 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,33(12):2270-2275
Due to the long lead time and great expense of traditional sample return mission plans to Mars or other astronomical bodies, there is a need for a new and innovative way to return materials, potentially at a lower cost. The Rapid Impactor Sample Return (RISR) mission is one such proposal. The general mission scenario involves a single pass of Mars, a Martian moon or an asteroid at high speeds (7 km/s), with the sample return vehicle skimming just 1 or 2 m above a high point (such as a top ridge on Olympus Mons on Mars) and releasing an impactor. The impactor strikes the ground, throwing up debris. The debris with roughly the same forward velocity will be captured by the sample return vehicle and returned to Earth. There is no delay or orbit in the vicinity of Mars or the asteroid: RISR is a one-pass mission. This paper discusses some of the details of the proposal. Calculations are presented that address the question of how much material can be recovered with this technique. There are concerns about the effect of Mars tenuous atmosphere. However, it will be noted that such issues do not occur for RISR style missions to Phobos, Deimos, or asteroids and Near Earth Objects (NEOs). Recent test results in the missile defense community (IFTs 6–8 in 2001, 2002) have scored direct hits at better than 1 m accuracy with closing velocities of 7.6 km/s, giving the belief that accuracy and sensing issues are developed to a point that the RISR mission scenario is feasible. 相似文献