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.     

材料裂纹型损伤愈合过程观测

对预制裂纹型损伤的愈合过程进行了实时原位观察，结果发现裂纹愈合过程分为裂尖钝化、裂纹分节、裂腔球化、孔洞愈合及质量均匀化等几个明显阶段。所得结果与金相法得到的纯铁的裂纹愈合过程相符，通过建立相关裂纹愈合模型分析认为裂纹愈合过程必须满足一定的热动力学条件，空位迁移是裂纹愈合的主要机制。     

基于内容分析法的航空公司网站营销绩效评估

遵循服务导向的原则,从航空公司网站目标顾客的角度出发,针对信息服务、互动服务和电子商务服务等构建了评价指标体系;进而采用内容分析法,选择内地民航客运市场14家航空公司的简体中文网站进行了绩效评估;并采用非参数检验的手段,进行了进一步的实证研究。     

辽宁省城镇化内涵及其影响因素分析

城镇化是社会发展的必然趋势，是我国现代化建设的必由之路，但目前对城镇化内涵的还没有一个完整统一的认识。城镇化内涵应该包括经侪城镇化、产业结构城镇化、人口城镇化、空间城镇化、生活方式城镇化等。从城镇化的内涵人手，对其影响因素进行分析，旨在对辽宁城镇化的进程进行测量，以期进一步推动辽宁城镇化的进程。     

月球电离层掩星探测研究

日本SELENE/KAGUYA探测任务提供了研究月球电离层的机会。采用无线电掩星探测技术和趋势外推算法,消除地球电离层和行星际等离子体的干扰影响,残余的信号相位信息的变化反映了月球电离层的信息,估算出月球周围附近近似对称分布的稀薄电离层中电子总含量(TEC)约为每立方米10-14个。     

The impact of large solar events on the total electron content of the ionosphere at mid latitudes

Ionospheric disturbances associated with solar activity may occur via two basic mechanisms. The first is related to the direct impact on the ionosphere of EUV photons from a flare, and the second by prompt electric field penetration into the magnetosphere during geomagnetic storms. In this paper we examine the possibility that these two mechanisms may have an impact at mid latitudes by calculating the total electron content (TEC) from GPS stations in Mexico during several large X-ray flares. We have found that indeed large, complex flares, which are well located, may affect the mid latitude ionosphere. In fact, in the solar events of July 14, 2000 and April 2001 storms, ionospheric disturbances were observed to increase up to 138 and 150 TECu, respectively, due to the influence of EUV photons. Also, during the solar events of July 2000, April 2001, Halloween 2003, January 2005 and December 2006, there are large ionospheric disturbances (up to 393 TECu in the Halloween Storms), due to prompt penetration electric field, associated with CME producing geomagnetic storm.     

国产高模量碳纤维抗真空紫外辐照性能试验研究

通过地面模拟试验研究了真空紫外辐照对国产BHM3高模量碳纤维质量损失率的影响,并采用扫描电子显微镜（SEM）、原子力显微镜（AFM）和X射线光电子能谱（XPS）仪对辐照前后的样品进行微观分析。结果表明,随着真空紫外辐照剂量增加,碳纤维质损率呈现先增加后平缓现象,质量损失率较少;紫外辐照作用前后碳纤维表面形貌和元素组成基本未变,说明其具有良好的抗紫外辐照性能。     

低烟耐烧蚀聚氨酯弹性体力学性能的研究

以1,6-六亚甲基二异氰酸酯(HDI)、聚氧化丙烯多元醇(PPG)、3,3/-二氯-4,4/-二氨基二苯甲烷(MOCA)为原料合成了聚氨酯弹性体,并进一步将消烟耐烧蚀反应型填料填充其中制得低烟耐烧蚀聚氨酯弹性材料。系统的研究了软段含量、交联度对产物力学性能的影响。结果表明:随软段长度的增加,HDI型聚醚弹性体的拉伸强度、邵氏硬度和回弹率降低,扯断伸长率增加;随着交联度的增加其扯断伸长率、邵氏硬度降低,拉伸强度则先降低后增加,回弹率却大幅增加。同时研究结果表明填充消烟耐烧蚀反应型填料的HDI型聚醚弹性体不仅具有优异的力学性能,还具有优异的低烟耐烧蚀性能。     

一种离子聚合物金属复合材料拉伸试验研究

离子聚合物金属复合材料（IPMC）是一种新型的电致激活功能材料。为了研究IPMC的驱动特性,需要掌握其基本力学性能。通过化学镀方法,在一种与Nafion 117相似的离子交换膜表面镀金属铂（Pt）,制备了IPMC拉伸试样;测定了不同含水量情况下,IPMC试样尺寸的变化;通过拉伸试验和扫描电镜（SEM）形貌观察,研究IPMC含水量与拉伸性能之间、含水量与弹性模量之间的变化关系。研究表明：在聚合物基底溶胀状态下,试样各向尺寸变化相同,IPMC的弹性模量随其含水量的增加而降低,呈幂指数趋势下降;针对表面金属（Pt）镀层厚度为5~20 μm的IPMC试样,表层金属产生龟裂,且Pt元素在厚度方向上分布不均匀,若仍采用层合板理论对其弹性模量进行预测,将导致较大的误差。本文结果可为IPMC的力学建模、失效形式等研究提供有益的参考。     

近红外光谱测定NEPE胶组分含量

研究了近红外光谱测定NEPE胶中硝化甘油、丁三醇三硝酸酯、聚乙二醇含量的方法,采用相关系数、显变分析、间隔偏最小二乘法、遗传算法等方法选择波长,对相关实验条件和影响因素进行了研究.实验结果表明,数据平移处理可以有效改善样品吸光度与浓度之间的相关性;遗传算法选择波长优于相关系数法和间隔偏最小二乘法,显变分析不适合于本项研究;近红外光谱法快速测定NEPE胶组分含量的结果与标准分析方法的测定结果一致,两者相差小于1%;水分含量的变化、正常加热操作对NEPE胶组分含量测定的影响不明显.