多因素组合下发射载体出管速度偏差预估方法

运用极限偏差、合成标准差、统计分析、蒙特卡洛仿真等多种预估方法,对发射载体出管速度偏差进行对比分析。分析结果表明,极限偏差法工程应用成熟,但预估结果偏于保守,适用于影响因素尚未认知完全的工程型号;对于影响因素比较明确的系统,运用统计分析法、合成标准差法得到的发射载体出管速度预估值一致性好,方法简单,且具有较高的准确性;蒙特卡洛法计算过程复杂,可通过大量仿真计算获取出管速度的分布特性,得到对应不同指标的分布概率,相比其他几种方法,计算结果更加科学、合理。工程型号应用时,可根据实际需要组合使用上述方法进行发射载体出管速度偏差预估分析。     

CFCC的几种声学参量表征方法比较

化学气相渗透(CVI)制备的CFCC的质量控制非常困难。研究该材料质量的无损检测方法对材料使用及性能表征等都具有重要意义。针对声衰减严重的问题,采用穿透法测量各声学参量,用声速、衰减、非线性等相关参量评价材料的均匀性,同时用金相法进行对比测试。结果表明:声速、衰减、非线性等参量可准确地评价材料均匀性,其中声速评价是最成熟的表征方法。     

A flow sheet for the conversion of lunar regolith using fluorine gas

This work reviews and expands upon the previous fluorination processes for in situ production of oxygen and silicon from lunar regolith. The process units were simulated and a flow sheet was developed to determine the product distribution and energy requirements. Our results show that 0.21 kg silicon and 0.32 kg oxygen can be produced per kg regolith processed with a total cooling duty of 17 MJ/kg regolith and electrical duty of 29 MJ/kg regolith. The payload mass required for the process is estimated as 16 kg/kg regolith processed per day.     

清代王维诗歌接受中的两个变化

文学史对王维诗歌的接受是一个漫长而又复杂的历史过程，不同时代对于王维诗歌有不同态度。与前人相比，清人对王维诗歌的接受出现了两个新的变化：第一，清人摆脱了长期以来诗坛“王孟”齐名的观点，将“孟不及王”的诗歌主张推向了一个新阶段；第二，清人走出了盛唐诗歌首推李杜其次王维的观点，提出王维与李白、杜甫鼎力三足的诗歌主张。     

非对称投弹及非对称挂载补偿控制技术研究

针对战斗类飞机非对称投弹和非对称挂载这类情况,分析了投弹时横向扰动及纵向机动时横向耦合的机理,描述了其对飞行安全的威胁;通过引入所投弹质量、位置以及飞机法向过载,设计了非对称投弹/非对称挂载补偿控制律.仿真验证结果表明:该补偿控制律可消除上述两种情况下的横向扰动,有助于非对称投弹时飞机状态的保持,更重要的是提高了非对称挂载情况下着陆的安全性.     

于无声处听惊雷——论明清才子佳人小说的情节自创性

明末清初的才子佳人小说在其"一见钟情(诗赋传情)"、"小人拨乱"、"及第团圆"的结构模式中,形成了看似"千部一套"的思维定势,但在这种模式化的内蕴中,却产生在小说情节、叙事形式上的变幻,使得这一时期的才子佳人小说犹如暗香疏影般显示出独特的审美魅力。     

一种电子天平测量结果的数据处理优化方法

电子天平具有数字化特性和较高的分辨力。本文通过与质量差值法的对比,提出一种新的电子天平测量结果的处理方法——比例系数法,并通过理论和实践验证了此方法的可行性。     

“中青年教育研究基金”管理初探

"中青年教育研究基金"课题，是民航学院科研工作普遍展开的一个侧重面。简要地分析了"中青年教育研究基金"设立后的现状和存在的问题；重点探讨了科学选题与充分论证是提高课题申报水平和完成率的关键；提出了在加深认识的同时，应采取措施从管理上增大工作保障的力度。通过提高申报水平，加强管理，保证"中青年教育研究基金"课题的质量和圆满完成，使"中青年教育研究基金"课题走上一条健康发展的研究道路。     

Influence of ionospheric perturbations in GPS time and frequency transfer

The stability of GPS time and frequency transfer is limited by the fact that GPS signals travel through the ionosphere. In high precision geodetic time transfer (i.e. based on precise modeling of code and carrier phase GPS data), the so-called ionosphere-free combination of the code and carrier phase measurements made on the two frequencies is used to remove the first-order ionospheric effect. In this paper, we investigate the impact of residual second- and third-order ionospheric effects on geodetic time transfer solutions i.e. remote atomic clock comparisons based on GPS measurements, using the ATOMIUM software developed at the Royal Observatory of Belgium (ROB). The impact of third-order ionospheric effects was shown to be negligible, while for second-order effects, the tests performed on different time links and at different epochs show a small impact of the order of some picoseconds, on a quiet day, and up to more than 10 picoseconds in case of high ionospheric activity. The geomagnetic storm of the 30th October 2003 is used to illustrate how space weather products are relevant to understand perturbations in geodetic time and frequency transfer.     

Kinetic theory of the current sheath. II. Effect of polarization on the stability of a current sheath

A procedure for investigating the stability of a current sheath, taking into account the effect of plasma polarization, is offered. The kinetic equation with a self-consistent electromagnetic field for perturbation of the distribution function is solved. On the basis of this solution, the tensor of dielectric permeability for a non-electroneutral current sheath plasma is calculated, and the dispersion equation for the study of possible instability modes of this current sheath is obtained. The instability of the current sheath of the magnetospheric tail with respect to tearing perturbations, and the influence of the effect of plasma polarization on the development of tearing instability, are investigated.