Ionospheric heating due to solar flares as measured by SROSS-C2 satellite

The data on thermal fluctuations of the topside ionosphere have been measured by Retarding Potential Analyser (RPA) payload aboard the SROSS-C2 satellite over the Indian region for half of the solar cycle (1995–2000). The data on solar flare has been obtained from National Geophysical Data Center (NGDC) Boulder, Colorado (USA) and other solar indices (solar radio flux and sunspot number) were download from NGDC website. The ionospheric electron and ion temperatures show a consistent enhancement during the solar flares. The enhancement in the electron temperature is 28–92% and for ion temperature it is 18–39% compared to the normal day’s average temperature. The enhancement of ionospheric temperatures due to solar flares is correlated with the variation of sunspot and solar radio flux (F10.7cm). All the events studied in the present paper fall in the category of subflare with almost same intensity. The ionospheric electron and ion temperatures enhancement have been compared with the IRI model values.     

Study of TEC changes during geomagnetic storms occurred near the crest of the equatorial ionospheric ionization anomaly in the Indian sector

GPS satellites data obtained at Bhopal (23.16° N, 77.36° E, geomagnetic latitude 14.23° N) India were analyzed to study the TEC changes during several geomagnetic storms (−300 nT < Dst < −50 nT) occurred in 2005–2007. We had segregated the storms according to the Dst value, i.e. moderate storms (−100 nT < Dst ? −50 nT), strong storms (−150 nT < Dst < −100 nT), and severe storms (Dst less than −150 nT). Total of 21 geomagnetic storms (10 moderate, 9 strong, 2 severe) are considered for the present study. Deviation in vertical total electron content (VTEC) during the main phase of the storm was found to be associated with the prompt penetration of electric field originated due to the under-shielding and over-shielding conditions for almost all geomagnetic storms discussed in this paper. For most of the storms VTEC shows the positive percentage deviation during the main phase while it shows positive as well as the negative deviation during the recovery phase of the storms. The −80% deviation in VTEC was found for geomagnetic storm occurred on July 17, 2005 and the negative trend continued for recovery phase of the storm. This was mainly due to the thermospheric composition changes by Joule heating effect at auroral latitudes that generate electric field disturbance at low latitudes. Traveling ionospheric disturbances (TIDs) were responsible for the formation of wave like nature in VTEC for the storms occurred on May 15, 2005, whereas it was not observed for storm occurred on August 24, 2005.     

关于域F上的向量空间V的一个性质的证明

利用扩张域论述方法，证明域Ｆ上的向量空间Ｖ的一个基本性质，即在Ｆ上，Ｖ关于Ｆ的基底的元数等于维数（Ｖ：Ｆ）。     

计算空气动力学的流场和图形显示技术

本文阐述了计算空气动力学流场和图形显示的重要性,它的基本方法和主要内容;介绍了在VAX计算机上研制的计算空气动力学流场和图形显示软件的主要功能。     

Synthesis of Iron-containing Carbon Microparticles from Deoiled Asphalt and Ferrocene

The deoiled asphalt as the carbon source and the ferrocene as the metal source and the catalyst precursor were chosen to synthe-size iron-containing carbon microparticles through co-carbonization at the temperature of about 450 ℃ for 3 h. The resulting products were treated at 2 000 ℃ for 2 h. All samples were examined by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The results show that the iron particles in the heat-treated material are completely coated by carbon. In addition to the fully filled carbon microparticles as well as hollow carbon ones, also form carbon fibers with hollow centers. The formation mechanism of the as-prepared products was discussed briefly.     

先进风洞气源系统的研制与运行

系统包括空气压缩、空气处理、储气、冷却水供应和中央监控等五个分系统,空压机的吸入流量为248m3 min,排气压力为2.4MPa,成品气常压露点达-38℃,可以满足一座0.6m量级的高速风洞对气源的需要。该系统在与800m3储气容积配套时,能保证在气体流量达140kg s、持续时间达40s的风洞试验中,其总温变化不超过1.5K。     

总温传感器动态特性的方向敏感性研究

讨论了气流方向对一种机载总温传感器动态特性的影响，发现气流偏角对传感器的动态特性有很大的影响，首次提出了总温传感器动态特性的方向敏感性概念。本文分析了其原因，并指出在设计、生产和使用过程中控制气流偏角的大小，否则将破坏传感器的动态性能。这一结论也适用于与结构类型相似的其它总温传感器。     

烧蚀材料的多光谱真温测量法

应用棱镜分光式多波长光电高温计对氧乙炔焰烧蚀材料的真实温度进行了测量。精心地选择波段及处理方法使烧蚀材料剥离、水蒸汽及烟雾影响减至最小，采用一点标定技术解决了高温区标定问题。     

对高温低周疲劳寿命预测模型的评价

高温低周劳寿命预测方法对于承受变幅载荷的高温构件的设计具有重要意义。本文系统介绍了迄今这方面所取得的研究成果，特别对目前在国内外影响较大的ＳＲＰ等几个ＨＬＦ寿命预测的经典参数模型和近些年发展起来的预测ＨＬＦ寿命的损伤力学方法作了较为详细的评价，并指出存在问题和研究方向。     

外挂及特种天平的粘贴处理

本文介绍了在外挂及特种天平的粘贴处理中,应变片的几种粘贴方法以及简单的天平温度效应补偿方法。