Reduction of hydroelastic responses of a very-long floating structure by a floating oscillating-water-column breakwater system

The hydroelastic responses of a very-long floating structure (VLFS) placed behind a reverse T-shape freely floating breakwater with a built-in oscillating water column (OWC) chamber are analyzed in two dimensions. The Bernoulli–Euler beam equation is coupled with the equations of rigid and elastic motions of the breakwater and the VLFS. The interaction of waves between the floating rigid breakwater and the elastic VLFS is formulated in a consistent manner. It has been shown numerically that the structural deflections of the VLFS can be reduced significantly by a suitably designed reverse T-shape floating breakwater.     

湖泊水体微生物四醚膜脂化合物研究进展

来源于微生物膜脂的甘油二烷基甘油四醚类(GDGTs)化合物是近年来被广泛用于古环境定量重建研究的化合物之一,究其原因在于此类化合物对环境响应敏感,特别是温度与pH值等,据此而建立的一系列GDGTs指标有效定量重建海洋、湖泊、泥炭以及土壤等不同沉积载体的环境信息.目前已在全球范围广泛开展湖泊沉积物GDGTs的研究工作,相继建立的全球以及不同区域尺度的湖泊沉积物GDGTs校正方程,已被用于湖泊古环境的定量重建研究,有效记载古湖泊环境变迁信息.相较之下,基于湖泊水体GDGTs的调查工作则起步较晚,但越来越多的研究显示,不同类型湖泊水体普遍贡献GDGTs,然而究竟此类水生来源GDGTs是否与陆源以及湖泊沉积物GDGTs具有类似的分布,以及他们对环境因素的响应如何,这都为湖泊古温度定量重建研究带来不确定性.基于此,本文总结这10年来湖泊水体GDGTs研究工作的进展,首先阐述湖泊水体不同来源(古菌以及细菌)GDGTs的分布情况,研究发现水体不同层位GDGTs浓度以及各组分之间存在差异,并且水深在不同湖泊对GDGTs浓度以及各组分相对比例的影响存在差异.此外还总结湖泊水体中古菌来源isoGDGTs以及细菌来源brGDGTs的生物来源,并进一步分析环境因素对不同深度水体GDGTs分布的影响,虽然温度依然是影响水体中GDGTs分布的首要因素之一,然而湖泊水深、温度以及水体中溶解氧浓度等因素存在着一定的耦合关系,这些因素往往协同作用于水体GDGTs,因此会为评估环境因素对水体GDGTs的影响带来难度.     

地震海洋学研究进展

传统船舶调查获取海洋水体温盐资料的方法在水平方向上分辨率较低,而用反射地震探测海洋水体特性的方法--地震海洋学,能有效提高海水温盐资料在水平方向上的分辨率.概述了近5年来地震海洋学的发展过程,重点介绍了地震海洋学方法在海洋锋面观测、水团边界划分、海洋内波分析、中尺度涡旋等方面的研究成果,以及AVO、全波形反演等反射地震处理方法在海洋水体特性研究中的应用.比较了地震海洋学方法与声层析技术、高频声技术等声学方法应用于海洋水体特性研究的异同.并展望了下一步研究工作的重点:①有关地震反射剖面的各种参数与海洋水体温盐结构物理模型的联系及其定量分析;②以研究海洋水体特性为目标的地震反射剖面的处理方法;③海洋地震调查历史数据的应用.     

概括平差模型的解法探讨

分析了概括平差模型系数矩阵可能出现非列满秩情况的原因,研究了如何使系数矩阵为列满秩矩阵,避免了系数矩阵为非列满秩时的复杂解算过程。     

Analytical and experimental investigations on seismic performance of exterior beam–column subassemblages of existing RC‐framed building

Seismic performance of exterior beam–column subassemblages of reinforced concrete structure designed and detailed on the basis of the provisions of Eurocode and Indian Standards at different stages of their evolution is evaluated. Performance of the subassemblages designed and detailed according to the three different stages of codal evolution (gravity load design, ‘Nonductile’, and ‘Ductile’) is evaluated through analytical formulations and experimental investigations. In the ‘NonDuctile’ specimens, it has been observed that the shear distortion and degradation in stiffness and strength are significantly high. Performance of the ‘Ductile’ specimens based on Eurocode and Indian Standards is almost similar in terms of strength and stiffness degradation. Nevertheless, the specimen designed on the basis of Indian Standard shows higher energy dissipation at a given drift ratio. In the analytical study, shear and flexural failure of members of subassemblage and shear failure of the joint are considered as possible modes of failure of the beam–column subassemblage. For evaluating the shear strength of the joint region, a soften strut‐and‐tie model is used. Analytically obtained strengths based on the failure criteria of different components of the specimens have been first validated with experimental results and then used to determine the strength of the specimens. The investigation could indicate even the mode of failure at local level. It is utmost important to mention here that even the ductile specimens dissipate most of the energy through the development of damage in the joint region, which is neither desirable nor safe for the stability of whole structure. Copyright © 2013 John Wiley & Sons, Ltd.     

海黍子乙酸乙酯相提取物的抑菌和体外免疫活性的研究

研究7 种海黍子(Sargassum kjellmanianum)乙酸乙酯相提取物的抗菌活性和对小鼠免疫细胞功能的影响, 筛选出抗菌和体外免疫活性较强的提取物。考察7 种提取物的抗菌活性, 以及对小鼠腹腔巨噬细胞RAW264.7 增殖、脾淋巴细胞增殖、释放NO、吞噬中性红能力的影响。抑菌实验结果表明, 7 种提取物对真菌无明显的抑制作用, 而针对不同的细菌表现出不同的程度的抑制活性; 免疫实验结果表明, 乙酸乙酯相的7 个样品都具有一定的体外免疫活性, 不但可以促进小鼠巨噬细胞RAW264.7 增殖和体外刺激淋巴细胞增殖, 还可以促进小鼠腹腔巨噬细胞产生NO和吞噬中性红。     

煤层陷落柱高分辨率地震探测技术

在华北、华东及西北地区近20多个煤田的石炭二叠系中，普遍存在着因煤系地层基底厚层灰岩古岩溶塌陷形成的煤层陷落柱，尤以山西省西山及汾河沿岸的煤田、河北省太行山中段的煤田更为普遍。煤层陷落柱发育形态分为圆锥形、筒形、斜塔形、不规则形等特点，应用高分辩地震勘探技术，根据陷落柱发育区反射波同相轴中断、扭曲、能量变弱、连续性变差、分叉合并或圈闭、产状突变等特征，可有效地探测其空间位置及形态。     

水脉泽寄主星系的倾角分析

迄今已经在104个河外星系中检测到水脉泽辐射.同其它没有检测到水脉泽的星系相比,水脉泽星系可能隐含着某种或某些特殊性质.收集了到当前为止(截止2008.09)发表的所有水脉泽星系以及相关的观测资料.计算得到了这些源的星系盘的倾角,并分析讨论了这些水脉泽源星系盘和脉泽盘的倾角可能存在的相关.统计发现只有大约10%的盘脉泽源的星系盘侧面对着我们的视线.然而VLBI对6个盘脉泽源高空间分辨率的成图观测显示那些旋转脉泽盘都是近似侧向的,脉泽盘的倾角都大于80°.对大多数水盘脉泽星系而言,他们的星系盘和脉泽盘方向不一致,这可能间接支持盘脉泽仅仅同星系核相关.为了探讨遮蔽物质的由来和水脉泽辐射的放大机制,对整个水脉泽样本的脉泽光度,X射线吸收气体柱密度和寄主星系倾角的可能相关进行了分析.结果显示高密度的遮蔽物质主要来自于星系核区,而水脉泽辐射的放大更可能发生在围绕核的尘埃盘(～100Pc)或更小尺度的核盘上.     

Study on Ozone Change over the Tibetan Plateau

This paper reviewed the main results with respect to the discovery of low center of total column ozone (TCO) over the Tibetan Plateau (TP) in summer, and its formation mechanism. Some important advances are summarized as follows: The fact is discovered that there is a TCO low center over the TP in summer, and the features of the background circulation over the TP are analyzed; it is confirmed that the TP is a pathway of mass exchange between the troposphere and stratosphere, and it influences the TCO low center over the TP in summer; models reproduce the TCO low center over the TP in summer, and the formation mechanism is explored; in addition, the analyses and diagnoses of the observation data indicate that not only there is the TCO low center over the TP in summer, but also TCO decrease trend over the TP is one of the strong centers of TCO decrease trend in the same latitude; finally, the model predicts the future TCO change over the TP.