Connection between winter mesopause region temperatures and diurnal LF reflection height variations measured at Collm

Scale height, H, estimates are calculated from the decrease/increase of ionospheric virtual reflection heights of low-frequency (LF) radio waves at oblique incidence in suitably defined morning intervals around sunrise during winter months. The day-to-day variations of H qualitatively agree with daily mean temperature variations around 90 km from meteor radar measurements. Since mesospheric long-period temperature variations are generally accepted to be the signature of atmospheric planetary waves, this shows that LF reflection height measurements can be used for monitoring the dynamics of the upper middle atmosphere. The long-term variations of monthly mean H estimates have also been analysed. There is no significant trend, which is in agreement with other measurements of mesopause region temperature trends.     

BPFER/DSX体系固化反应动力学与热性能

采用DSC研究了有机硅固化剂1,3-二氨丙基-1,1,3,3-四甲基二硅氧烷(DSX)与双酚F环氧树脂(BPFER)的固化动力学。BPFER/DSX体系的非等温固化反应曲线和dα/dt-t曲线表明,该反应符合自催化反应模型的基本特征。T-β曲线预测的固化工艺的凝胶温度、固化温度和后固化温度分别为36、87、138℃。采用E变量法分析得该体系的固化反应表观活化能为46.70～50.54 kJ/mol,与Starink、Kissinger、Ozawa、Boswell等方程的验证结果基本一致。采用E常量法求得该体系不同升温速率下的固化反应动力学方程,动力学方程预测值与实验值十分吻合。TG和DTG曲线表明,BPFER/DSX固化物的耐热性优于BPFER/DDM固化物。     

O2 evolution and cyclic electron flow around photosystem I in long-term ground batch culture of Euglena gracilis

Based on the purpose of better exploring the function of green producers in the closed aquatic biological life support system, the condition of dynamic O₂ evolution and performance of cyclic electron flow around photosystem I (CEF-PSI) in long-term ground batch culture of Euglena gracilis were studied, the relationship between linear electron flow (LEF) and CEF-PSI was revealed, the function of CEF-PSI was investigated. Excellent consistency in O₂ evolution pattern was observed in cultures grown in both closed and open containers, O₂ evolution was strictly suppressed in phase 1, but the rate of it increased significantly in phase 2. CEF-PSI was proposed to be active during the whole course of cultivation, even in the declining phase 3, it still operated at the extent of 47–55%. It is suggested that the relationship between LEF and CEF-PSI is not only competition but also reciprocity. CEF-PSI was proposed to contribute to the considerable growth in phase 1; it was also suggested to play an important protective role against photosystem II (PSII) photoinhibition at the greatly enhanced level (approximately 80–95%) on the 2nd day. Our results in this research suggest that E. gracilis had very particular photosynthetic characteristics, the strict O₂ evolution suppression in the initial culture phase might be a special light acclimation behavior, and CEF-PSI could be an important mechanism involved in this kind of adaptation to the changeable light environment.     

嫦娥五号探测器GNC系统设计

为实现我国首次月球样品无人采样返回任务,设计了嫦娥五号(Chang’E 5)探测器制导、导航与控制(GNC)系统.根据任务要求和探测器特点,GNC系统设计分为轨道器GNC子系统、返回器GNC子系统和着上组合体GNC子系统.给出了嫦娥五号探测器GNC系统的架构设计、工作模式以及在轨飞行结果.结果表明,GNC系统设计正确,成功完成了动力下降、起飞上升、交会对接、返回再入等关键动作,实现了月球表面起飞上升、月球轨道交会对接以及携带月壤以近第二宇宙速度二次再入返回的三项首次任务,各项功能性能满足任务要求.     

高温、高应变率LY12铝压缩动态力学性能的实验研究

摘要：利用配备自动组装系统和高温加热系统的φ5mm直径的Hopkinson压杆,对温度在20℃～400℃、应变率在5×103s-1～1.4×104s-1范围内LY12铝的动态压缩力学性能进行了实验研究。实验中采用波形整形技术,有效地消除了入射波的高频振荡,提高了测试精度。实验结果表明：当实验温度低于200℃时,温度的影响较小,而高于200℃时,材料的温度软化效应将十分明显,且随着温度的升高,流动应力逐步降低;LY12铝的性质接近于线性硬化材料,随温度的升高,其硬化模量逐步降低;在5×103 s-1～1.4×104 s-1应变率范围内,LY12铝的动态压缩性能的应变率效应并不明显。     

K8E飞机综合保障系统工程

从现代飞机综合保障系统工程的角度,分析总结K8E飞机综合保障的技术与管理创新和升级工作,着重介绍了与传统售后服务不同的飞机综合数据库管理系统、地勤培训软件、飞行训练模拟器、地面维护模拟器、外场维护综合测试车的开发以及在保障工程中发挥的效能。     

湘鄂渝黔边域定位：“中国绿心”游憩第一区——以大湘西北地区为例

湘鄂渝黔边界区域具有独特的地域文化资源与迷人的自然生态资源,且处在中国地理版图的心脏部位,故称之为“中国绿心”。整合该区域游憩文化资源,构建跨区域的游憩核心区,提升核心竞争力,有利于培育以奇特自然生态体验、社会传统民俗欣赏与诗意栖居生活享受等为主要内容的中国游憩第一区。其路径选择在于：制定新绿色战略,打造绿色品牌,保育绿色生态,发展绿色产业集群,营建绿色城镇,弘扬绿色文化,启动绿色机制。     

飞机结构搭接件腐蚀试验研究

分析了导致海军飞机结构腐蚀的主要因素,基于飞机地面停放环境谱,对航空LY12CZ铝合金等多种材料搭接试验件进行了5,10,15,20,30等多个当量年限的加速腐蚀试验及修复后加速腐蚀试验及海洋环境下的暴露试验,利用显微镜对试件表面涂层、金属基体材料腐蚀情况进行观察和测量,根据腐蚀评价指标对试验件腐蚀状况进行了分析比较,...     

Effects of Different Molten-salt on the Synthesis of Hexagonal Barium Ferrite

Hexagonal-plate BaFe12O19 nano-particles were prepared by combining the co-precipitation and molten-salt method. The effects of molten-salt NaCl on the products have been compared with those of KCl. The X-ray diffraction analysis,the environment scanning electron microscopy and the vibrating sample magnetometer were used to measure their characteristics. The results show that the mol-ten-salt KCl is helpful to obtain pure phase while the molten-salt NaCl will prompt the crystallinity of particles to increase. It is also found that, given the molten-salt of NaCl and that of KCl of the same quantity, the particles formed are also the same size. The size of particles slightly increases as the quantity of the salt increases. Moreover, the sample prepared under 200% NaCl salt system has mag-netization of 71.5 emu/g.     

对预警机相控阵雷达主瓣干扰的可行性分析

相控阵雷达是当前广泛采用的一种战术雷达，它可以地面、舰船为平台，也可以飞机为平台。机载平台中，除了作多用途雷达外，也可用作预警机预警雷达（如美Ｅ－８Ａ中的ＡＰＹ－３）。由于它具有高的主瓣增益和超低副瓣电平、相关接收技术，加上有的相控阵雷达采用实时自适应数字波束形成技术，使用灵活的控制和排序软件可有效对付多部干扰机，给对主瓣干扰带来极大困难。对相控阵雷达干扰有多种方法，本文提出一种分布式干扰方法，即