Determination of Partial Factors of Breast Wall on Top of Sloping Breakwater

- By applying the theory of structural reliability, reliability analyses for the stability of a breast wall on the top of a sloping breakwater are carried out. Based on the analyses, the method for determining partial action / load factors and partial resistance factors of breast walls is expounded, and the design expressions with partial factors are given. The values of partial action / load factors and partial resistance factors are recommended preliminarily according to the computation for breast walls with typical cross-sections.     

西昆仑西段三叠纪两类花岗岩年龄测定及其构造意义

西昆仑造山带海西晚期-印支早期(三叠纪)花岗岩发育,但已有的测年资料、岩石地球化学研究及少量的构造学观察还没有对本区这一时期造山事件的时间尺度做到准确把握。对西昆仑西段海西晚期两类构造特征完全不同的花岗岩露头尺度的观察、锆石U-Pb定年结果表明,一类含石榴子石片麻状花岗岩形成时代为240.5 ±1.8 Ma,表现出同造山过程中的花岗岩变形特征;另一类块状含角闪石花岗岩的年龄为228.2±1.5 Ma。根据两个岩体的构造特征,结合前人的研究及地球化学特征,表明含石榴子石片麻状花岗岩形成于同碰撞造山时期,是甜水海地体与西昆仑南带晚古生代岛弧沿麻扎-康西瓦缝合带碰撞峰期的产物,代表了沿麻扎-康西瓦分布的古特提斯洋一个分支的闭合,而228 Ma块状含角闪石花岗岩形成于碰撞造山后的伸展背景。220-190 Ma持续发育的花岗岩是南昆仑地体拼合到北昆仑地体之后在其南部形成的新的深成岩浆弧带。这一研究为西昆仑海西晚期-印支早期构造演化提供了更精细的时间制约。     

Discovery of the Jiawengmen Stromatolite Assemblage in the Southern Belt of Eastern Kunlun, NW China and Its Significance

1 Introduction The stromatolites of the Jiawengmen area in the southern belt of the Eastern Kunlun orogen were initially interpreted as vortex structures by the Regional Geological Survey Team, Qinghai Bureau of Geology and Mineral Resources in 1973; these samples were then identified as algal fossils of Sinian age by the Nanjing Institute of Geology and Paleontology (Qinghai Bureau of Geology and Mineral Resources, 1973). In 1994, Chen and Luo (1998) discovered some stromatolites, i…     

Characteristics of present-day active strain field of Chinese mainland

On the basis of the GPS data obtained from repeated measurements carried out in 2004 and 2007,the horizontal principal strain of the Chinese mainland is calculated,which shows that the direction of principal compressive strain axis of each subplate is basically consistent with the P-axis of focal mechanism solution and the principal compressive stress axis acquired by geological method.It indicates that the crustal tectonic stress field is relatively stable in regions in a long time.The principal compressive stress axes of Qinghai-Tibet and Xinjiang subplates in the western part of Chinese mainland direct to NS and NNE-SSW,which are controlled by the force from the col-lision of the Eurasia Plate and India Plate.The principal compressive strain axes of Heilongjiang and North China subplates in the eastern part direct to ENE-WSW,which shows that they are subject to the force from the collision and underthrust of the Eurasia Plate to the North America and Pacific plates.At the same time,they are also af-fected by the lateral force from Qinghai-Tibet and Xinjiang subplates.The principal compressive strain axis of South China plate is WNW-ESE,which reflects that it is affected by the force from the collision of Philippine Sea Plate and Eurasia Plate and it is also subject to the lateral force from Qinghai-Tibet subplate.It is apparent from the comparison between the principal compressive strain axes in the periods of 2004～2007 and 2001～2004 that the acting directions of principal compressive stress of subplates in both periods are basically consistent.However,there is certain difference between their directional concentrations of principal compressive stress axes.The sur-face strain rates of different tectonic units in both periods indicate that the events predominating by compressive variation decrease,while the events predominating by tensile change increase.     

第五届<地震学报>编委会在北京召开

1999年12月29日,在庆祝中国地震学会成立20周年纪念活动的专业委员会分会场,由主编陈运泰院士主持召开了<地震学报>编委会会议.出席庆祝活动的30余位编委及编辑部全体成员参加了会议.首先,副主编张以勤编审就<地震学报>创刊20年来的工作向编委们作了汇报,主要谈及20年来<地震学报>概况、 <地震学报>刊登文章的重点领域、 <地震学报>在国内科技期刊中的地位,以及学报文章所反映的我国地震科学工作正在面向世界、不断扩大对世界的影响,并对<地震学报>的未来作了展望…….     

VERTICAL DISTRIBUTION CHARACTERISTICS OF ATMOSPHERIC AEROSOLS IN LIAONING

16 aircraft missions were conducted for the measurement of atmospheric aerosols in separatedays of late spring and early summer of 1996 and 1997.The paper deals with detailed analysis ofthe variation in vertical/horizontal distributions of the concentration of the particles and their sizedistribution at 0—5 km above ground,and with the relations to temperature and relative humiditydocumented in general.Evidence suggests that the concentrations show different distributionfeatures in vertical above and below the cap of the mixed layer:the particle size distribution issubject to a range of forming mechanisms,displaying a multi-modal pattern:the horizontalconcentration experiences remarkable variation:temperature and relative humidity stratificationshave conspicuous influence on the concentration and size distribution of aerosols.     

一种基于面向对象的企业建模技术

将一种面向对象的思想应用于企业建模中 ,利用面向对象的技术实现功能模型和信息模型的集成。对象的独立性和封装性增强了系统的鲁棒性 ,能适应企业功能和结构的动态重组。提出了对象状态图、对象状态矩阵和对象属性矩阵 ,容易贯彻“自顶向下”的系统分析策略 ,使系统的外部视图(用户视图 )与内部视图 (计算机视图 )统一 ,达到清晰的、完整的描述系统的目的。     

"坝体决口"孕震模式

根据中国大陆流动重力测量资料、跨断层流动测量资料、大面积水准测量资料、GPS测量资料、大震现场考察结果和地震活动特征提出了一种新的孕震模式,并认为这是地震孕育过程中可能存在的主要模式之一.     

三峡井网地下流体动态在水库蓄水前后的变化

在系统分析长江三峡诱发地震地下水动态监测井网2001～2002年8个井台16个测项的地下流体正常动态及其影响因素的基础上，调查研究了井网外围50km范围内两个中等地震震例，对比分析了2003年三峡水库蓄水前后各测项动态的变化。发现水库蓄水对三峡井网地下流体动态的影响是局部的．推测三峡库首区近期诱发中等以上水库地震的可能性不大；同时分析了受水库蓄水影响测项的异常特征及其机理，认为深入研究此类问题对推进地震监测与预报科学的发展有重要意义。     

来稿须知

1　《山西地震》是地震科技季刊 ,以刊登地震监测、预报、科研、工程地震、地震社会学等方面的成果以及防震减灾知识为主 ,亦刊登国内外地震科技情报资料等。辟有地震预报、观测分析、工程抗震、异常识别、地震社会学、技术革新、技术交流、综合评述、科研简讯、学术动态、问题讨论、外文译摘、外语阅读之窗、专题汇编、新技术讲座、科普园地、资料等栏目。2　稿件文字力求言简意赅 ,引用数据、公式应准确 ,文稿字数以 3 0 0 0～ 5 0 0 0字为妥 ,文稿前请附中、英文题名、作者、单位 ,邮政编码 ,2 0 0字左右的摘要 (中文摘要请用报道性文摘 …