利用核对软件降低MARK IV格式磁带回放数据的误码率

由于磁带回放的不稳定性及磁带与处理机的不匹配 ,导致由磁带导入硬盘的数据误码率很高 ,影响了送入处理机的数据可用率。结果显示 ,采用核对软件能将数据可用率提高一个数量级     

STUDY ON BEIJING''''S EMERGING MOBILE COMMUNICATION INDUSTRIAL CLUSTER AND ITS POLICY IMPLICATIONS

1INTRODUCTIONClusters,definedasgeographicallyproximategroupsofinterconnectedcompaniesandassociatedinstitutionsinparticularfields,linkedbycommonalitiesandcomple-mentarities(PORTER,2000),havearousedanintenseinterestofurbanandregionalplanningresearchersandpolicymakersoverthepastdecades.Itiswidelyrecog-nizedthatclusterscanpromoteproductivityandinno-vation,developlocalcompetitiveadvantages.Popular-izedbyMichaelPORTERinhisbook“TheCompetitiveAdvantageofNationsin1990,theclusterisnotanewcon…     

从统计分析看控制东海重矿物分布的因素

任何地质作用过程都是复杂的,东海也不例外,其沉积过程具有长期性、继承性和叠加性的特点.因而反映在矿物组合及其分布变化上较为复杂,影响因素颇多.然而,运用数学地质方法却可帮助我们寻找和确定其主要的影响因素,查明它们的相互关系,甚至建立定量描述的模式.而这正是传统地质学研究中的难题之一.     

Interfacial geochemistry of barium in suspension and sediment from Zhujiang Estuary

Chemical forms of Ba are determined in samples of suspension and sediment from the Zhujiang Estuary. Their interfacial geochemical processes are discussed. Total suspended Ba content is between 2. 4 and 40. 4 μg/L, and mostly exists in the crystalline form (43. 5%), secondly in the Fe-Mn oxidative form (23.1%). Percentages of organic, carbonate and exchangeable forms are 14. 8%, 11. l%and 7.4%, respectively. Total content of Ba in the sediment is between 158. 6 and 48. 0 ug/g. Percentages of crystalline form, Fe-Mn oxidative form and carbonate form are 78. 4% ,13. 5%and 8. 2%, respectively. Organic and exchangeable forms are not detected. The study on the mechanism of interfacial movement suggests that the salinity range of 10 is the turning point for the varied distribution of Ba. The subsidence of crystalline form affects the decrease of Ba content in suspension. The decrease mostly takes place in the salinity range lower than 10, which corresponds to the high value of Ba content in the sediment. The     

南海南部晚中新世的放射虫及其环境探讨

南海是东亚古季风产物的主要沉积盆地，保存着比陆地更加完整和连续的沉积记录。详细分析了ODP1143号钻井晚中新世的放射虫化石群，主要根据标志种Diartus petterssoni,D.hughesi和Stichocorys delmontensis等的分布特征，分别建立了南海南部晚中新世的RN6，RN7和RN8等3个放射虫化石带，并讨论了其地层年龄。探讨了以地层中放射虫的丰度变化特征等在南海南部作为东亚古夏季风活动替代性指标的可能性，初步说明东亚古夏季风可能早于8．7Ma B.P．出现，约在8．24Ma B.P.强化达到高峰，认为与印度季风的出现几乎同步或略早。     

山东胜利油田海洋石油勘探开发现状及前景分析

胜利油田海上勘探区 ,位于渤海湾南部的极浅海海域 ,其范围为 :西起四女寺河口 ,经套儿河口、老黄河口、新黄河口、小青河口 ,东到潍河口 ,海岸长 4 1 4km,胜利矿产登记线内面积 4 870 km2 ,水深一般 0～ 5m,最深 1 8m。截止 2 0 0 0年年底 ,已完成二维地震 71 3 6.1 km,三维地震 1 588.58km2 ,完钻探井 1 0 2口 ,测井解释油气层井 87口 ,试油 85口 ,其中 74口获工业油流 ,6口获低产油流。发现了埕岛、埕北 3 0、新滩 3个油田 ,在明化镇组、馆陶组、东营组、沙河街组、中生界、上古生界、下古生界、太古界中发现了 8套含油层系 ,6种类型的油气藏 ,已探明含油面积 1 45.8km2 ,石油地质储量 3 860 9万 t;控制含油面积57.5km2 ,石油地质储量 894 8万 t,其中埕岛油田是渤海域发现最早的亿吨级油田 ,目前已建成 2 1 6万 t年生产能力 ,累积产油 1 0 57万 t。根据两轮资源评价及勘探实践的认识 ,与本区有关的 8个生油凹陷 (岐口、沙南、渤中、埕北、桩东、青东、莱州湾、潍北 )总资源量约 1 2 .0亿 t,目前已找到探明加控制石油地质储量为 4 .75亿 t,仍有较大的勘探开发潜力。今后将对 8个构造带 (埕子口、埕岛、埕北 3 0、长堤、垦东、青东、青坨子、潍北 )进行勘探 ,落实探明储量 ,进一步投入开发 ,为胜利油田     

Optimum design of filament-wound multilayer-sandwich submersible pressure hulls

Submersible pressure hulls with fiber-reinforced multilayer-sandwich constructions have been developed in recent years as substitutes for classical metallic ring-stiffened pressure hulls. This study aims to optimize the design of filament-wound multilayer-sandwich submersible pressure hulls, taking into consideration the shell buckling strength constraint, the angle-ply laminated facing failure strength constraint and the low-density isotropic core yielding strength constraint under hydrostatic pressure using the hybrid genetic algorithm (HGA). The thickness of the facing, the thickness of the core layer, the orientation angle of the fibers in the facings and the shear modulus of the core material are taken as design variables. A sensitivity analysis is performed to study the effects of the operational depths and the hull shell geometry parameter, the length-to-diameter ratio (L/D), on the optimal design of filament-wound multilayer-sandwich submersible pressure hulls with graphite/epoxy, glass/epoxy and boron/epoxy composite facings. The results reveal that the optimal weight of various sandwich pressure hulls increases linearly with the operational depth, but it is almost unchanged as the geometry paramter. Furthermore, Graphite/Epoxy is the best choice for the material of the facings in a light-weight design. With reference to wall design, Boron/Epoxy is the best choice for the material of the facing at shallow depths, but Graphite/Epoxy is the best choice at extreme depths. Results of this study provide a valuable reference for designers of underwater vehicles.     

Effect of the Twin Jetties as A Regulating Structure at the Tao-er Estuary

The phase one project of the twin jetties at the Tao-er Estuary yields no effect on the flow, and there is a large area of deposition. A numerical model is employed to simulate the flow field, and the scouring and silting in the channel be-tween the two jetties are analyzed. The results show that the effective tidal flux between the two jetties is reduced due to the notch located at the heel of the east jetty, and the effect of contraction-flush is not obvious. As for the regulation of this kind of estuary under the tide action, the capability of tidal flux should be fully used.     

基于Oracle XML DB的XML文档存储技术的研究

随着XML技术的快速发展,人们正在寻找一种更有效的方式来解决XML文档的存储问题,本文通过Oracle XML DB技术来存储XML文档,并用一个基于.net的应用程序实现了对XML文档进行简单的DML操作。     

土钉抗拔承载力的原位试验研究

根据土钉现场抗拔试验数据,分析了钉材、浆液龄期等因素对土钉抗拔承载力的影响,建议了合理的下层土钉开挖时间。最后通过试验土钉抗拔力反算土体与锚固体的极限粘结强度,并与规范推荐值进行了比较。