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111.
丛凯  高贤志  张宝鹏 《推进技术》2021,42(10):2161-2168
碳化硅纤维增强碳化硅陶瓷基复合材料(CMC-SiCf/SiC)具有低密度、耐高温、高比强度等优点,是下一代高推重比航空发动机热端部件的主要候选材料之一。然而,该材料在燃气环境中面临严重的腐蚀问题。因此,需要在材料表面涂覆环境障涂层进行防护。本文综述了环境障涂层的选材要求、材料发展阶段、涂层制备技术、涂层考核与失效等,指出了环境障涂层今后在选材、制备、考核与评价的发展方向。  相似文献   
112.
    
地基增强系统(GBAS)基准站的布设方式会直接影响系统精度与完好性,且与机场环境、卫星星座以及当地电离层活动情况密切相关。然而,美国联邦航空管理局(FAA)发布的GBAS选址标准只是给出了基准站布设的基本要求,没有深入考虑上述因素的影响。因此,GBAS基准站布设方案设计与评估方法需要进一步研究。首先,基于采集数据比较分析了5个机场典型GBAS基准站布设和伪距校正误差标准差。然后,结合理论和仿真研究了基准站个数对GBAS性能的影响,以及基线长度对星历故障监视和异常电离层梯度监视性能的影响。最后,提出一种GBAS基准站布设方案设计和评估方法,并辅以V型跑道的4个方案示例,为根据机场实际情况、GBAS星历故障监视和异常电离层梯度监视实际需求等设计和选择合适的方案提供参考。  相似文献   
113.
杨春  常文兵  李铁航 《航空学报》1997,18(4):466-469
军用飞机可靠性监控的目的在于对现役的军用飞机、机群的可靠性状况及飞机维修大纲的实施情况进行连续的监督与控制,以提高军机的系统效能,充分保证军机的战斗力。结合中国国情论述了军用飞机,监控指标的选取、计算、控制界限的确定及具体实现。  相似文献   
114.
将清洁生产的理论与方法导入高等教育业,探讨高等教育清洁生产的意义、内容与途径.在高等教育业大力推广清洁生产,开展节能、降耗、控污、治污等环境保护活动,是实现高等教育业可持续发展的重要途径.  相似文献   
115.
Huge magnetic clouds of plasma emitted by the Sun dominate intense geomagnetic storm occurrences and simultaneously they are correlated with variations of spectra of particles and nuclei in the interplanetary space, ranging from subtermal solar wind ions till GeV energy galactic cosmic rays. For a reliable and fast forecast of Space Weather world-wide networks of particle detectors are operated at different latitudes, longitudes, and altitudes. Based on a new type of hybrid particle detector developed in the context of the International Heliophysical Year (IHY 2007) at Aragats Space Environmental Center (ASEC) we start to prepare hardware and software for the first sites of Space Environmental Viewing and Analysis Network (SEVAN). In the paper the architecture of the newly developed data acquisition system for SEVAN is presented. We plan to run the SEVAN network under one-and-the-same data acquisition system, enabling fast integration of data for on-line analysis of Solar Flare Events. An Advanced Data Acquisition System (ADAS) is designed as a distributed network of uniform components connected by Web Services. Its main component is Unified Readout and Control Server (URCS) which controls the underlying electronics by means of detector specific drivers and makes a preliminary analysis of the on-line data. The lower level components of URCS are implemented in C and a fast binary representation is used for the data exchange with electronics. However, after preprocessing, the data are converted to a self-describing hybrid XML/Binary format. To achieve better reliability all URCS are running on embedded computers without disk and fans to avoid the limited lifetime of moving mechanical parts. The data storage is carried out by means of high performance servers working in parallel to provide data security. These servers are periodically inquiring the data from all URCS and storing it in a MySQL database. The implementation of the control interface is based on high level web standards and, therefore, all properties of the system can be remotely managed and monitored by the operators using web browsers. The advanced data acquisition system at ASEC in Armenia was started in November, 2006. The reliability of the multi-client service was proven by continuously monitoring neutral and charged cosmic ray particles. Seven particle monitors are located at 2000 and 3200 m above sea level at a distance of 40 and 60 km from the main data server.  相似文献   
116.
Systematic recording of the cosmic radiation commenced in Hobart in 1946 and at Mawson in Antarctica in 1955, making these two of the longest running cosmic ray observatories in the world. For the IGY, observations were also made at a sub-Antarctic island and near the equator, and an airborne survey of the nucleonic component was made from Geomagnetic Latitude −60°, south of Australia, to Japan and back. At Hobart there were neutron monitors, vertical and inclined muon telescopes, an ionization chamber, and two muon telescopes at ∼40 m of water equivalent underground. The research based on these and other observations determined the energy dependence of the Forbush and 11-year variations and concentrated, in particular, on understanding the anisotropic nature of galactic cosmic rays up to 150 GeV; the anisotropies in the onset phase of Forbush decreases; and the anisotropies in solar cosmic ray events. An investigation was initiated to calculate the trajectories and cutoff rigidities of cosmic rays in a high order simulation of the geomagnetic field. This was completed in 1959–60.  相似文献   
117.
实现SMP机群虚拟化的方法   总被引:1,自引:0,他引:1  
机群是一类重要的并行计算机体系结构,成本低廉,可扩展性强,但编程复杂,管理难度大.利用虚拟化技术可以将机群抽象成具有共享内存特征的虚拟机,支持共享内存的编程模式,从而克服机群的不足.当前,在该领域有少量探索性的研究成果,但都不能支持对称多处理机(SMP,Symmetric Multiprocessor)机群虚拟化.本文提出一种新颖的虚拟化SMP机群的方法,即利用硬件虚拟化技术,在操作系统(OS,Operating System)之下构建分布式虚拟机监视器(DVMM,Distributed Virtual Machine Monitor),通过DVMM对机群的资源进行感知、整合、虚拟化和呈现,使SMP机群对OS呈现为一台具有共享内存特征的虚拟机;通过DVMM与OS配合,实现在虚拟机上透明地运行并行应用软件.  相似文献   
118.
智能移动机器人在制造业、服务业、军事、星际探测等领域获得了广泛的应用,导航是智能移动机器人实现自主控制需要解决的重要问题.对不同领域智能移动机器人导航技术发展现状进行了调研.针对环境感知与建模、定位和路径规划等机器人导航控制关键技术,深入分析了其实现方法.在此基础上归纳出智能移动机器人导航控制未来的发展趋势.  相似文献   
119.
针对虹桥机场通信管网人井的监控问题,本文利用基于模糊综合函数的目标识别融合理论实现多传感器决策级数据融合,提高通信人井井盖监测的准确性,并以B/S模式构建分布式通信人井多传感器集中智能监控系统。这两种理论保证了本套在线实时监控系统成功地应用于虹桥机场,保证了机场的通信管网安全畅通。  相似文献   
120.
During the recent ground level enhancement of 13 December 2006, also known as GLE70, solar cosmic ray particles of energy bigger that ∼500 MeV/nucleon propagated inside the Earth’s magnetosphere and finally accessed low-altitude satellites and ground level neutron monitors. The magnitude and the characteristics of this event registered at different neutron monitor stations of the worldwide network can be interpreted adequately on the basis of an estimation of the solar particle trajectories in the near Earth interplanetary space. In this work, an extended representation of the Earth’s magnetic field was realized applying the Tsyganenko 1989 model. Using a numerical back-tracing technique the solar proton trajectories inside the magnetospheric field of the Earth were calculated for a variety of particles, initializing their travel at different locations, covering a wide range of energies. In this way, the asymptotic directions of viewing were calculated for a significant number of neutron monitor stations, providing crucial information on the Earth’s “magnetospheric optics” for primary solar cosmic rays, on the top of the atmosphere, during the big solar event of December 2006. The neutron monitor network has been treated, therefore, as a multidimensional tool that gives insights into the arrival directions of solar cosmic ray particles as well as their spatial and energy distributions during extreme solar events.  相似文献   
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