半无限空间中SH波被空腔和刚性包体所散射(英文)     

曾心传  A.S.Cakmak 《大地测量与地球动力学》1985,(3)

根据波尔近似,借助于波动积分方程,近似求解半无限弹性空间中平面SH波由圆形空腔和刚性包体所散射的问题。获得了空腔表面上的散射位移、作用于被包体上的剪应力、半空间表面形变以及远场位移的近似公式。在数值计算中,ka(k=波数,a=空腔或被包体的半径)取为1.0,γ(SH波的入射角,从垂向方向起算)取为π/4。  相似文献   

.Net环境下空间数据缓存方案的设计与实现     

李滨  侯小牛  常德海  陈欣 《海洋测绘》2009,29(3):34-37

空间数据查询效率的优劣决定着三层体系结构空间信息系统的应用效果。空间数据缓存技术是提高空间数据查询效率的有效方法之一。在数据缓存技术逐渐成熟的今天，如何利用数据缓存技术来构建空间数据缓存是目前研究的热点。基于Microsoft新的数据缓存技术，借助常用的格网索引，在客户端和应用服务器端开辟空间数据缓存区，以降低数据的传输量，减少用户的请求响应时间，从而提高空间数据查询效率。在利用版本控制技术实现空间数据缓存的同时，解决客户端、应用服务器和数据库服务器的数据一致性问题，确保空间数据的有效性和可用性。  相似文献   

TRAVEL TO SOUTHERN SINKIANG     

S. Ting 《地理学报》1948,(1)

This paper records my geological and geomorphological observations enroute from Urumuchito Aksu. Leaving Urumuchi on August Ist, we passed through the graben trough of Davan,followed the course of Bayan Ho to Toksun in the Turfan Basin. Glaci-fluvial deposits were seen in the valley of Bayanho at 980m. above the sea. Toksun city has an elevation read from  相似文献   

Simulation Study on High Energy Cosmic Electron Detection by Shower Image     

Rong Xu Jin Chang S. Torii K. Kasahara T. Tamura K. Yoshida 《天体物理学报》2007,7(6):839-844

Many projects have recently been carried out and proposed for observing high energy electrons since it is realized that cosmic ray electrons are very important when studying the dark matter particles and the acceleration mechanism of cosmic rays. An imaging calorimeter, BETS （Balloon-borne Electron Telescope with Scintillator fiber）, has been developed for this purpose. Using pattern analysis of the shower development, the electrons can be selected from those primary cosmic ray proton events with flux heights one-tenth that of the electrons. The Monte-Carlo simulation is indispensable for the instrument design, the signal trigger and the data analysis. We present different shower simulation codes and compare the simulation results with the beam test and the flight data of BETS. We conclude that the code FLUKA2002 gives the most consistent results with the experimental data.  相似文献   

Simulation Study on High Energy Cosmic Electron Detection by Shower Image     

S.Torii  K.Kasahara  T.Tamura  K.Yoshida 《中国天文和天体物理学报》2007,7(6):839-844

Many projects have recently been carried out and proposed for observing high energy electrons since it is realized that cosmic ray electrons are very important when study-ing the dark matter particles and the acceleration mechanism of cosmic rays. An imaging calorimeter,BETS (Balloon-borne Electron Telescope with Scintillator fiber),has been de-veloped for this purpose. Using pattern analysis of the shower development,the electrons can be selected from those primary cosmic ray proton events with flux heights one-tenth that of the electrons. The Monte-Carlo simulation is indispensable for the instrument design,the sig-nal trigger and the data analysis. We present different shower simulation codes and compare the simulation results with the beam test and the flight data of BETS. We conclude that the code FLUKA2002 gives the most consistent results with the experimental data.  相似文献   

Distribution, Use Pattern and Prospects for Conservation of Medicinal Shrubs in Uttaranchal State, India   总被引：1，自引：0，他引：1  

Bhupendra S. Adhikari Mani M. Babu Prem L. Saklani Gopal S. Rawat 《山地科学学报》2007,4(2):155-180

The present paper gives an insight into the distribution and use pattern of medicinal shrubs in Uttaranchal State. A total of 222 medicinal and aromatic shrub species have been appended based on secondary information. Euphorbiaceae, Rosaceae, Verbenaceae, and Fabaceae have the highest repre- sentatives of medicinal shrubs. Twenty one families had one species each in medicinal use. Verbenaceae and Euphorbiaceae in the sub-tropical region, Rosaceae in the temperate region, and Ericaceae and Rosaceae in the sub-alpine and alpine regions, respectively, had the highest representatives of medicinal shrubs. The distribution of medicinal shrubs was 42 % in sub-tropical, 29 % in warm temperate, 13 % in cool temperate, 9 % in sub-alpine and 7 % in the alpine region. Of the total species, 70 medicinal shrubs were native to the Himalayas and 22 native to Himalayan region including other Hima- layan countries. The most frequently used plant parts for various ailments were leaves (31 %) and roots (23 %). Most shrubs are being used for the diseases, viz. skin diseases, dysentery, cough, fever, wounds, and rheumatism. The present paper will help in the execution of strategies for promotion and cultivation of medicinal shrubs in Uttaranchal State.  相似文献   

The 21st International Geological Congress, Norden 1960     

Henning Sφrensen 《《幕》》2007,30(2):125-130

  相似文献   

A possible precessing nozzle and the Lense-Thirring effect in blazar 3C 454.3     

Shan-Jie Qian  S. Britzen  A. Witzel  T. P. Krichbaum  Heng-Qian Gan  Long Gao 《天文和天体物理学研究(英文版)》2014,(3):249-274

The kinematics of superluminal components in blazar 3C 454.3 are studied.Nine components are included:superluminal knots R1,R2,R3,R4,A,B,C and D(from Britzen et al.2013) and C4(from Pauliny-Toth 1998).We find that their kinematics derived from VLBI observations can be consistently interpreted in terms of a jet precession scenario with a period of about 14.5 yr.We discuss the model fits of their trajectory,distance from the core and apparent velocity.We show that the bulk Lorentz factor(in the range 4 to 15) derived for these components does not have any dependence on the phase of the precession(or position angle for ejection).The LenseThirring effect is assumed to interpret the precession of the jet nozzle.The results obtained for blazar 3C 454.3 are only suggestive.They are not unique and have yet to be tested,but they might be useful for understanding the kinematics of superluminal components in blazars and for disentangling different mechanisms and factors.  相似文献   

东印度洋水体输运的季节变化及相关盐度变化     

L. A. A. N. Wickramasinghe  王卫强  刘雨  M. K. Abeyratne  W. C. Hemamali  K. B. S. S. J. Ekanayake 《南京气象学院学报》2020,12(4):472-482

利用20年（1992-2012年）的ECCO2模式模拟数据,主要研究了东印度洋（EIO）水体输运的季节变化.在EIO选取3个断面,分别为赤道、80°E和6°N.研究结果表明,跨赤道和80°E的季节输运主体部分大致相补偿.跨赤道的大部分水体输运局限在上层100 m,80°E的水体输运具有复杂结构,与显著的季风流、Wyrtki Jets（WJs）、赤道潜流（EUC）等有关.6°N上层水体净输运较小,但存在较强的边界流和相对较弱的内区流.纬向流的显著变化发生在80°E.在季风盛行季节,由于WJs减弱,赤道附近的水体输运以西向的梯度流为主,上层100 m的其余区域则主要受季风流控制.同样,由于EUC减弱,西向的梯度流与次表层东向的EUC之间也存在转换.在季风转换季节,季风流减弱,WJs与EUC分别在上层100 m和次表层占主导地位.此外,本研究还讨论了与季风流、WJs和EUC相关的盐水和暖水交换,有助于了解研究区域内温度和盐度的水平和垂直结构.  相似文献   

大气和植被生态及土壤系统水文过程相互作用的一些研究   总被引：9，自引：1，他引：8  

曾庆存  曾晓东  王爱慧  Robert E. Dickinson  Xubin Zeng  Samuel S.P. Shen 《大气科学》2005,29(1):7-19

利用我国测站的降水资料、卫星测得的OLR和高云量资料、SST和137°E次表层海温资料以及NCEP/NCAR再分析资料,分析了东亚夏季风的爆发和北进的年际变化特征及其与热带西太平洋热状态的关系.分析结果表明:当春季热带西太平洋处于暖状态,菲律宾周围对流活动强,在这种情况下,南海上空对流层下层有气旋性距平环流,西太平洋副热带高压偏东,从而使得南海夏季风爆发早;并且,当夏季热带西太平洋也处于暖状态,菲律宾周围对流活动也很强,在这种情况下,西太平洋副热带高压北进时,在6月中旬和7月初存在明显的突跳,从而使得东亚季风雨带在6月中旬明显由华南北跳到江淮流域,并于7月初由江淮流域北跳到黄河流域、华北和东北地区.这将引起江淮流域和长江中、下游夏季风降水偏少,并往往发生干旱,而黄河流域、华北和东北地区的夏季降水正常或偏多.相反,当春季热带西太平洋处于冷状态,菲律宾周围对流活动弱,在这种情况下,南海上空对流层下层有反气旋性距平环流,西太平洋副热带高压偏西,从而使得南海夏季风爆发晚;并且,当夏季热带西太平洋也处于冷状态,菲律宾周围对流活动也很弱,在这种情况下,西太平洋副热带高压北进时,在6月中旬或7月初向北突跳并不明显,而是以渐进式向北移动,从而使得东亚季风雨带一直维持在长江流域和淮河流域.这将引起此两流域夏季风降水偏多,并往往发生洪涝,而黄河流域、华北和东北地区的夏季降水偏少,发生干旱.作者还从非线性多平衡态动力理论说明了菲律宾周围对流活动强弱对西太平洋副热带高压北进时以突跳或渐进式向北移动起到重要作用.  相似文献