辽宁省夏季强降水天气环流特征分析     

曲晓波  张廷治 《辽宁气象》1996,(4):10-13

由于强降水而引发的洪涝是辽宁的主要灾害之一，做好强降水预报是做好洪涝预报的基础。中期预报以其较长的时效性，愈来禽引起人们的重视。随着科学技术的发展，在3～6天中期预报时效内准确预报强降水已成为可能。据统计，在综合考虑全省平均及分片平均候累积降水量的前提下，1961-1994年夏季辽宁省共发生强降水过程43次、较强降水过程40次。强降水过程不同于干旱过程，强降水过程一般具有突发性和持续时间短的特点，发生较强降水或强降水过程往往决定于候内一次降水过程的强度和持续时间。  相似文献   

强对流天气监测短时预报系统   总被引：1，自引：0，他引：1  

纪英惠  伍星赞  周彪  尹新怀 《气象》1996,22(8):20-23

作者在前３年研究和试验的基础上，研制了一套适合湖南实际情况的较完善的准客观强对流天气监测短时预报系统，它包括图形图象显示，雷达定量估算降水和强对流天气短时预报方法子系统。  相似文献   

《地质科技情报》专刊——《构造地质文集》评介     

曲梅兰 《地质科技情报》1996,(4)

《地质科技情报》专刊——《构造地质文集》评介曲梅兰（中国地质大学，武汉，４３００７４）为了继承和宏扬我国老一辈地质学家严谨治学，深入实践、勇于探索、不断开拓的优良学风，在构造地质学家朱志澄教授从事地质工作５０周年之际，本刊出版这期专刊以示祝贺。撰稿人...  相似文献   

全球构造研究专著《大陆裂谷对比——汾渭裂谷系与贝加尔裂谷系例析》评介     

曲梅兰 《地质科技情报》1996,(4)

全球构造研究专著《大陆裂谷对比——汾渭裂谷系与贝加尔裂谷系例析》评介曲梅兰（中国地质大学，武汉，４３００７４）这是一部由中、俄科学家联合组队共同协作完成的科研专著。该书由中国构造地质专家杨巍然教授、孙继源高级工程师、纪克诚教授、邢集善高级工程师与俄罗...  相似文献   

Comet Sugano-Saigusa-Fujikawa (1983V)--a small, puzzling comet     

Hanner MS  Newburn RL  Spinrad H  Veeder GJ 《The Astronomical journal》1987,94(4):1081-1087

Spectroscopic and infrared observations of Comet Sugano-Saigusa-Fujikawa (1983V) were obtained during its close approach to the Earth on 11-14 June 1983. The [O I] production rates of 1.8 +/- 0.9 x 10(26) atoms/s observed on 12.3 June and 7 +/- 3.5 x 10(26) atoms/s on 13.4 June lead to derived water-production rates of 3 x 10(27) mol/s on 12 June and 1.1 x 10(28) mol/s on 13 June. The abundances of the minor species NH2, CN, C2, and C3 are unusually low relative to [O I]. The upper limit to the average nuclear radius from our infrared and visual photometry on 12-13 June (assuming that the entire signal came from the nucleus) is approximately 370 m. The dust/gas mass ratio was <0.01 on June 12 and <0.005 on June 13.  相似文献   

Growth of rural population in Punjab, 1971-81     

Gill MS 《Population geography : a journal of the Association of Population Geographers of India》1987,9(1-2):62-72

Except for the decade 1941-1951, in which Punjab's population declined because of a huge exchange of population between India and Pakistan and a large loss of life, the decade 1971-1981 was the 1st decade since 1911 to experience a deceleration in the growth rate of the rural population of Punjab, India. The deceleration was due to out-migration to urban areas. The scheduled caste population increased 28.37% between 1971 and 1981, while the nonscheduled caste population increased by only 13.32%, which was considerably below the rate of natural increase. Nonscheduled castes had experienced substantial out-migration because of 1) improved transport and communication facilities which enabled them to move to urban centers; 2) mechanization of main farming operations and easy availability of migrant laborers which lessened the need for family labor; 3) the rise of a relatively mobile younger generation with a high literacy rate; 4) rapidly decreasing land holdings which strengthened the push factor in the countryside; and 5) rising aspirations, especially among the younger generation. In 1981, Sikhs constituted 71.3% of the rural population in Punjab, followed by Hindus (26.51%), Christians (1.25%), and Muslims (.89%). From 1971-1981, Muslims experienced the greatest increase (49.29%). Sikhs grew by 20.74% and Hindus by 9.02%. The Sikhs high growth rate was due to 1) a new technique for counting religious affiliation in which all members of a household are considered the same religion as the head of household and 2) conversion of Hindus to Sikhism. Hindus had a low growth rate because 1) the new method of counting religious affiliation and 2) rural-urban migration. The area with the lowest population increase resulted from industrialists and other nonagriculturists buying farmland, causing the agriculturists to move away to less desirable land. Conclusions are 1) the sharp rural-urban division along religious lines should be lessened, 2) Sikhs' lag in urbanization and upward mobility should be decreased, and 3) nonagriculturalists should be prevented from buying farm land from peasants along main roads and around urban centers.  相似文献   

闪长玢岩钠长石化的实验研究   总被引：3，自引：0，他引：3  

李九玲  刘玉山  缪婉萍  曲国林 《地质学报》1979,53(1)

钠交代是自然界分布广泛的一种热液蚀变。已经发现,变钠质岩石、钠长石化岩石与多种类型铁、铜、稀有元素矿床有密切的空间及成因上的联系。因此,在地质研究的基础上,实验研究钠质交代形成的物理化学条件以及它在成矿元素迁移富集中的作用是一个重要的课题。近年来,用实验方法研究钠长石及钠长石化已积累了一些资料,如塔特尔等人在较大  相似文献   

西太平洋底质及其分区   总被引：1，自引：1，他引：1  

朱佛宏  马道修  牛作民  朱成文  王志喜  曲高升 《海洋地质与第四纪地质》1984,(2)

海底沉积物的系统研究始于1872—1876年英国《挑战者》号的调查.第二次世界大战后许多国家都大力发展了深海调查.但到1968年深海钻探计划实施前,人们仍主要局限于松散沉积物的调查.本文论述的西太平洋海区是指东起夏威夷,西至亚洲大陆,南达新西兰和澳大利亚,北到白令海峡的广大海区(图1).底质的分布及其分类,主要是根据美国拉蒙特-多尔蒂地质调查所和我国的有关资料综合分析研究后完成的.本区沉积物按其物质来源大致可分为陆源的、生物的和多源的三大类.  相似文献   

Parametric Equation of Stress Concentration Factor for Circular X-Joints Under Axial Loads     

曲淑英张国栋  张宝峰王心健 《中国海洋工程》2007,21(1):51-64

In engineering practice,tubular X-joints have been widely used in offshore structures.The fatigue failure of tubular X-joints in offshore engineering is mainly caused by axial tensile stress.In this study,the stress concentration factor distribution along the weld toe in the hot spot stress region for tubular X-joints subject to axial loads have been analyzed by use of finite element method.Through numerical analysis,it has been found that the peak stress concentration factor is located at the saddle position.Thereafter,80 models have been analyzed,and the effect of the geometric parameters of a tubular X-joint on the stress concentration factor has been investigated.Based on the experimental values of the numerical stress concentration factor,a parametric equation to calculate the stress concentration factor of tubular X-joints has been proposed.The accuracy of this equation has been verified against the requirement of the Fatigue Guidance Review Panel,and the proposed equation is found capable of producing reasonably accurate stress concentration factor values for tubular X-joints subject to axial loads.  相似文献   

西北干旱地区水资源现状、问题及对策   总被引：10，自引：0，他引：10  

冯起  曲耀光 《地球科学进展》1997,12(1):66-73

通过对西北干旱地区的水资源现状分析,得出西北干旱区水资源存在着水资源量不足、分布不均、严重浪费、水环境恶化等问题;解决该地区水资源问题的相应对策,即:强化管理,科技兴水,合理配置,高效利用,优化环境,加大投入和持续利用等。  相似文献