流星暴的航天定义

定义ZHR^*以每小时穿过1000平方公里天顶截面的，能在铝质表面打出直径不小于1厘米的弹坑的流星体数，作为流星群对航天安全威胁强度的定量标志，给出了从ZHR到ZHR^*的换算公式．用ZHR^*取代ZHR来评价20世纪90年代以来的一些强流星雨，发现1998年的贾可比尼(天龙座)流星雨对航天安全来说，是比公认的1999、2001、2002年3次狮子座流星暴强数倍的更强流星暴．     

造山带中富集型上地幔的成因——以萨尔托海蛇绿岩块为例

发育于造山带中的蛇绿岩,其剖面下部的地幔橄榄岩部分是造山带地区富集型上地幔的直接标本。其地球化学特点是:主要元素Al_2O_3、TiO_2、CaO、Na_2O、K_2O强烈亏损,而REE,痕量元素和87Sr/86Sr则强烈富集;同时,143Nd/144Nd<0.511836,亦表明它们属于一个富集型的源区。 形成富集型上地幔的主要机制是地幔交代作用,富含不相容元素的低熔岩浆和富Ca-LREE流体与已亏损的地幔橄榄岩发生脉状交代和渗透交代反应,从而造成上地幔中不相容元素的富集。造山带富集型上地幔形成的构造环境是:洋壳从扩张脊向两侧运移并最终拼入造山带这段时间内。富集型上地幔不但存在于大陆区,而且亦存在于造山带地区,它可能是一种全球性的地球内部的化学作用。     

新疆黑英山-查汗沙拉-地那达坂地区锑矿成矿远景评价

我国西天山南段的黑英山-查汗沙拉-地那达坂锑多金属矿化区为中亚南天山成矿带的东延部分,区内广泛分布有泥盆系滨浅海含碳碎屑岩和碳酸盐岩,岩石具有较高的Sb背景场,异常多呈Sb、Au、As、Hg等元素组合异常出现,异常区内已发现有查汗沙拉、阿特达坂和地那达坂等多个锑矿(点)床.区内锑矿化及异常均受近Nw向大型逆冲推覆构造系统控制,具有良好的成矿条件和较大的找矿潜力.     

攀西地区铂族元素地球化学异常分布及其筛选

攀西地区不同时代地层的水系沉积物中铂族元素地球化学背景值具有明显的规律性分布.笔者通过对该地区铂族元素含量在各地层中的分布以及地球化学异常的圈定、归并和分类,结合有关铂族矿床地球化学特征的认识,通过对水系沉积物中Pt、Pd综合异常的筛选,在铂族元素综合衬值异常图的基础上共划分出Ⅰ类异常4个、Ⅱ类异常19个、Ⅲ类异常23个以及Ⅳ类异常14个.初步筛选出的19个Ⅱ类异常子区可为进一步开展铂族矿床找矿工作提供依据.     

三道通铜矿地质特征与找矿前景浅析

三道通铜矿位于吉林省桦甸市,华北地台北缘东段之辉南-桦甸-和龙成矿带上,产于高级变质区会全栈穹形构造的北西缘,夹皮沟矿田和王家店矿区之间.产于一定的围岩条件内,受北西向剪切带严格控制,与脉岩有着密切的关系,矿石类型为多金属含重晶石石英脉型,其规模为小型矿床,伴生铅、金、钨、钴等元素,以往找矿工作程度很低.通过对地质特征和成因类型的论述及成矿条件分析,指出了找矿方向并预测了发展前景.     

海洋综合测量声学系统间信号干扰的分析

针对海洋综合测量多种声学测量系统间的窄带相干声学干扰现象进行了理论分析，并针对克服窄带干扰提出了一些具有实用价值的建议。     

AN ANALYSIS OF ACOUSTICAL SCATTERING FROM ELASTIC OBSTACLES BY FINITE AND BOUNDARY ELEMENT COMBINATION APPROACH

A method combining boundary and finite element approaches as well as modal analysis to solve the acoustical scattering from elastic obstacle in infinite fluid is described. An elastic cylinder with finite length immersed in water is chosen as an example for numerical demonstration. The computed frequency response and direction pattern of the backscattering target strength of the cylinder are conformable to those measured.     

Seasonal and annual variations of marine sinking particulate flux during 1993~1996 in the central South China Sea

A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993~1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species (Globigerinoides sacculifer, G. ruber, Globigerinita glutinata, Neogloboquadrina dutertrei) and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution.     

珠江河口西南风强迫下潮流场的数值模拟

采用Backhaus三维斜压模型模拟了均匀西南风场对珠江口近岸海域的影响，并与无风情况作了对比；通过对珠江河口盐度场及风生环流的分析比较，结果表明，模型较为真实地再现了夏季珠江河口的水动力学特性。