Theoretical Calculation of Floating Breakwater Performance

- In this paper, the theoretical calculation of floating breakwater performance in regular waves with arbitrary wave direction is discussed. Under the hypothesis of linearized system and applying the strip theory, we can solve the boundary condition problems of diffraction potential and radiation potential. Introducing the asymptotic expression of the wave velocity potential at infinity and using wave energy conservation, we can separately calculate the transmitted waves generated by the sway, heave and roll motion of the floating breakwater and by the fixed breakwater. Finally, we define the amplitude ratio of the transmitted wave to the incident wave as the transmitted wave coefficient CT which describes the floating breakwater effectiveness. Two examples are given and the theoretical results obtained by the present method agree well with experimental results.     

广西河池地区的地震活动及发震机制的岩石实验解释

本文讨论了广西河池地区地震活动的时空分布、应力场“窗口”效应和小震级高烈度等特征,並利用岩石实验的某些结果对该区地震的发震机制作了一些定性解释。该区是一个两组断裂交汇的应力敏感区,地震是在低应力条件下在极不均匀介质宁原有裂隙发生粘滑的结果,其特殊的地体环境下可能构成蕴育大震的条件,其地震活动不会对邻近的龙滩库坝区造成威胁。     

朱夏教授研究大陆边缘构造演化的思路

本文介绍了朱夏教授研究大陆边缘构造演化的思路,概括了“活动论构造历史观”在时间上、空间上、属性上的特征。朱夏教授强调地球岩石圈水平运移演化历史,提出了中生代以前古老的“潘基亚”大陆边缘和以后的年青的巨板块边缘;结合中国地质构造独特点,精辟地论述了中国大陆边缘构造的网络格架。     

China’s intra- and inter-national carbon emission transfers by province: A nested network perspective

Science China Earth Sciences - Since China carries an increasingly significant responsibility in carbon emission reduction, a systematic assessment from the multi-scale and multi-regional...     

四氯化碳重液法分离蒙脱石

提出了一种新的蒙脱石重液分离方法,蒙脱石在正辛胺水溶液中浸过后,密度降至１．６０×１０３ｋｇ／ｍ３以下,可用ＣＣｌ４作重液实现与其它粘土矿物及杂质的分离。用７．５ｍｏｌ／ＬＮａＯＨ溶液处理此含有正辛胺的蒙脱石,可得纯度很高的钠蒙脱石。用此法进行蒙脱石定量分析,所得结果与国际铸造协会推荐的溴仿酒精重液法相符合,且成本低、操作方便、污染小。     

碳酸盐岩区断裂构造的水文地质性质研究─—以天津蓟县山前断裂为例

研究系统边界及其性质是认识岩溶水系统结构特征和地下水运动规律的基础工作之一,也可为进一步建立水文地质概念模型和水资源评价数学模型提供依据。本文利用断层岩性质及溶蚀作用特征、裂隙发育特征、水化学特征、岩溶水同位素特征、水动力场等方面资料,相互补充,相互印证,详细论证了蓟县地区岩熔水系统的重要边界之一──蓟县山前断裂的水文地质性质。研究结果认为:蓟县山前断裂总体上是属于透水断层,局部地段由于所处构造部位和含水层结构不同而呈阻水性质。      

Probabilistic characterization of cyclic shear modulus reduction for normally to moderately over-consolidated clays

Evaluation of the cyclic shear modulus of soils is a crucial but challenging task for many geotechnical earthquake engineering and soil dynamic issues. Improper determination of this property unnecessarily drives up design and maintenance costs or even leads to the construction of unsafe structures. Due to the complexities involved in the direct measurement, empirical curves for estimating the cyclic shear modulus have been commonly adopted in practice for simplicity and economical considerations. However, a systematic and robust approach for formulating a reliable model and empirical curve for cyclic shear modulus prediction for clayey soils is still lacking. In this study, the Bayesian model class selection approach is utilized to identify the most significant soil parameters affecting the normalized cyclic shear modulus and a reliable predictive model for normally to moderately over-consolidated clays is proposed. Results show that the predictability and reliability of the proposed model out performs the well-known empirical models. Finally, a new design chart is established for practical usage.     

上海芦潮港岸滩冲淤动态及原因探究

本文从杭州湾北岸历史变迁和上海南汇新老海塘建塘史叙述了南汇嘴发育过程的间歇性特点。位于南汇嘴嘴尖的芦潮港岸滩近５０年也呈现冲淤交替的特征，且冲淤过程由东向西传递。诱发这种冲淤波动的直接原因是摇头沙的偏转，而其根源应追溯到长江口河势的变化。本文以近５０年来长江口的两个事件──北槽和江亚南泓的形成──阐述了它们对芦潮港岸滩动态的影响。