A study on the asymmetries in flare lines

We calculate the H and CaII K profiles under different velocity models with chromospheric condensations and investigate the effect of the velocity in different layers on the profiles from a semi-empirical standpoint. The results show that the short-time, H blue asymmetry in the early stage of the flare can be caused by condensations in the transition zone, that the subsequent red asymmetry is the result of the downward motion of matter in the upper chromosphere, while the later CaII K asymmetries can be explained by downward velocities of 10–20 km/s in the middle and lower chromosphere.     

Tracing anthropogenic contamination in the Pearl River estuarine and marine environment of South China Sea using sterols and other organic molecular markers

5beta-Coprostanol together with eight other sterols and unresolved complex mixtures (UCMs) were quantitatively investigated for surficial sediments and surface waters to assess the impacts of anthropogenic activities on the Pearl River estuarine and marine environment of South China Sea. The studied area extends from the Pearl River Estuary southward to the open sea. 5beta-Coprostanol concentrations ranged from trace amounts to 53 microgg(-1) TOC in surficial sediments. The highest levels and highest percentages of coprostanol were found in the Pearl River estuary, especially in the inner estuary and those sites close to the submarine outfalls of Hong Kong. For waters, only in estuarine samples was coprostanol quantitatively detected, ranging from 11 to 299 ngL(-1). Bimodal UCM "humps" were observed for most sediment samples, with concentrations ranging from 215 to 10,491 microg g(-1) TOC in sediments and from 2 to 26 mcirogL(-1) in waters, respectively. Progressive seaward declines in concentrations were found for both 5beta-coprostanol and UCM in surficial sediments. Trace or no 5beta-coprostanol was found in open-sea samples. Concentrations of coprostanol and UCM in surficial sediments are correlated. These results imply that there are obvious anthropogenic contaminations in the Pearl River estuary. The submarine outfalls in Hong Kong represent important sources of the sewage pollution to the Pearl River estuarine sediments evidenced by a combination of coprostanol concentration, diagnostic indices, sterol profiles and UCM. No obvious dispersion or transport of the sewage contamination occurred from the Pearl River estuary to the open South China Sea indicated by fecal sterol biomarkers.     

滇西试验场区三维重力反演研究

本文依最新获得的滇西试验场区布格重力异常成果和近几年该区已有的人工地震测深资料，利用Ｐａｒｋｅｒ－Ｏｌｄｅｎｂｕｒｇ快速位场反演方法和文献［１］设计的反演计算程序，实施了多个密度界面的三维重力反演，首次获得了该区地壳上、中、下三界面的整体展布图像，分析了它们的细化结构，并结合本区重力异常特征讨论了界面图像的构造物理意义，结果表明：区内杨子板块地壳界面的去耦滑动远强于三江微板块，洱源—永胜一线的地壳半细颈结构是区内现代构造运动最活跃的地段。     

太阳γ射线研究的新进展

概述了太阳γ射线研究的新进展，特别是最近4年的进展，展望了未来的HESSI卫星空间探测研究。     

异模式嵌套及中期降水数值预报的试验

成功地将一有限区域细网格模式嵌套在T63L9全球谱模式中，并利用该嵌套模式 做了降水中期数值预报的试验。结果表明，嵌套的细网格模式预报的中期降水明显地优于该谱模式，要做好中期降水预报，使用嵌套模式是必要的。     

江苏旱涝灾害对农作物经济损失评估的探讨

江苏旱涝灾害常给农作物经济带来很大损失，本文从旱涝年灾情资料找出各级灾害强度及相应的灾情指标值，根据赂级灾害相应指标值和有关经济指标，建立灾害影响农作物经济的评估模型，应用评估模型进行各级灾害农作物经济损失的评估，通过统计和实际对照，证实评估模型的客观性和可行性。     

A Physical Method of Analyzing theMechanism of Continental StrongShocks from Crustal Movement

In order to analyze the mechanism of continental strong shocks from the angle of crustal movement using the data of repeated geodetic survey, this paper has proposed a physical method; it analyzes the mechanism of density change due to the occurrence of strong shocks by use of the physical quantity that reflects the time change of crustal density. ( 1 ) The general theory of the time change of density in the earth‘ s interior and the theory of the time change of single layer density have been introduced, and an algorithm of stepwise iteration has been proposed; (2) The effect of the change of single layer density caused by fault dislocation has been analyzed in brief; (3) The characteristics of the time change of crustal density in the south of the seismogenic region before the 1996 Lijiang earthquake with ML = 7.0 have been studied; (4) The precursor model or causal mechanism of strong shocks possibly existing in the time change of crustal density has been investigated preliminarily.     

粤港澳地区地震科技合作与交流的回顾及展望

粤港澳地区地理人文环境相同，三地在经济，科技和文化等方面联系密切，地震临测和地震科技方面的协作和交流也日益频繁，取得了可喜成果，回顾了近20年来三地震科技合作的历程，并展望了未来的合作前景。     

海底天然气水合物的饱和度预测技术

海底天然气水合物的储量主要取决于水合物的分布面积、水合物稳定带的厚度、沉积层的孔隙度及水合物的饱和度 (或充填率 )等 ,其中水合物在沉积物孔隙中的饱和度对其储量的估计具有重要意义。目前很难通过原地直接测量来获得这种饱和度数据 ,一般根据地球化学或地球物理方法取得。水合物饱和度预测技术主要有 :利用岩心孔隙水氯离子浓度、地球物理测井、地震波速度等间接手段。每一种技术都不是完善的 ,而海底含水合物的沉积物又是一个复杂的系统 ,在预测中应根据实际情况选择比较合适的方法 ,并尽量选择一种以上的方法或模型作多方法校正     

A Comparative Study on the Microbiological Characteristics of Soils Under Different Land—Use Conditions from Karst Areas of Southwest China

Microbiological and physical-chemical characteristics of subtropical forest,grassland and cropfield soils from the karst areas of Southwest China were investigated.The study revealed that the conversion of natural forest to other forms of land would lead to a reduction in soil organic C(26.2%-35.3%),total N(37.2%-55.8%),totalP(32.9%-43.6%),microbial biomass C(35.4%-49.1%),N(37.2%-55.8),and P(25.8%-41.9%).Comparative analysis of microbial activity in terms of basal soil respiration showed maximum activity in forest soil and minimum in cropfield soil.Analysis of microbial metabolic respiratory activity indicated a relatively greater respiratory loss of CO2-C per unit microbial biomass in cropfield and grassland than in forest soil.Considering the importance of microbial components in soil,it is concluded that land use in different ways will lead to the reduction of biological stabilty of soil.