地震载荷下桩-土-上部结构作用机理与数值模拟

桩-土-结构动力相互作用机理研究是提高动力作用下桩基础安全性的重要基础。在分析目前桩基抗震的主要计算模型及分析方法基础上,采用有限元软件ABAQUS,对桩-土-结构动力相互作用体系进行了水平地震荷载下的二维弹塑性有限元分析。比较了角桩、中间桩和中间边桩的剪应力幅值沿桩身的分布,得出了桩身剪应力幅值分布都呈桩顶大、桩尖小的倒三角分布;角桩剪应力幅值较大,边排中桩和中桩的剪应力幅值较小;随着桩间距的增大以及桩边长的减小,不同位置处的桩所分担的剪应力比例差距越来越小;桩土之间的滑移量在桩顶处大,桩尖处滑移量小;桩-土接触界面在动力作用过程中桩顶剪应力幅值有增大-减小-增大的变化规律。     

地震载荷下桩-土-上部结构作用机理与数值模拟

桩-土-结构动力相互作用机理研究是提高动力作用下桩基础安全性的重要基础.在分析目前桩基抗震的主要计算模型及分析方法基础上,采用有限元软件ABAQUS,对桩-土-结构动力相互作用体系进行了水平地震荷载下的二维弹塑性有限元分析.比较了角桩、中间桩和中间边桩的剪应力幅值沿桩身的分布,得出了桩身剪应力幅值分布都呈桩顶大、桩尖小的倒三角分布;角桩剪应力幅值较大,边排中桩和中桩的剪应力幅值较小;随着桩间距的增大以及桩边长的减小,不同位置处的桩所分担的剪应力比例差距越来越小;桩土之间的滑移量在桩顶处大,桩尖处滑移量小;桩-土接触界面在动力作用过程中桩顶剪应力幅值有增大-减小-增大的变化规律.     

Antennation and sexual performance of male digger wasps Sphex ingens Smith (Hymenoptera: Sphecidae)

Antennation can play several roles in hymenopteran copulation, mainly in wasps. The digger wasp Sphex ingens Smith has a very peculiar sexual behaviour, in which forced copulation is a striking element. However, communication through antennation during the pre-copulation and copulation phases and the relationship between the sexual performance of males and the final result of copulation require further clarification. The sexual behaviour of wild populations of S. ingens was filmed during the breeding season in a site between the beaches Meros and Aventureiro, Ilha Grande, southeastern Brazil. We assessed antennation behaviour, courtship duration, sexual performance, and genital clasping. Only successful males had the genital clasping assessed. Evidence found so far points out that the successful males showed better sexual performance – that is, they antennated more in a shorter courtship duration. Also, genital clasping in successful males did not depend on antennation, courtship duration, or sexual performance. Our results shed light on some aspects of the sexual behaviour of wasps, as they explain part of the sexual selection mechanisms adopted by the species.     

Morphology and larval development of Polydora cf. websteri (Polychaeta: Spionidae) in a tropical region of north-eastern Brazil

Polydora websteri belongs to a group of the Spionidae known as the Polydora complex, members of which are known for building tubes within the shells of mussels and for their ability to infest commercially valuable bivalves, which causes serious losses for malacoculture. P. websteri is a species subjected to increasing research due to the global scale at which these infestations occur. In this paper, we describe the larval development of P.cf. websteri associated with the oyster Crassostrea cf. brasiliana in a tropical region of north-east Brazil. The main structures of all stages of development were analysed and compared to other populations of P. websteri. Ovigerous capsules of P.cf. websteri were cultured in the laboratory and the larval stages were analysed until metamorphosis. Ovigerous capsules were present in all sampling intervals, indicating that this population exhibits continuous reproduction. Up to 21 capsules per tube were found, and the number of eggs per capsule varied from 20 to 40. All observed eggs developed into larvae. Larval development from egg to recruitment stage did not exceed 13 days. Metamorphosis occurred when larvae attained 17 chaetigers, at which stage important diagnostic characteristics were revealed, such as the spines on chaetiger 5. The developmental stages of P.cf. websteri larvae, and the morphological features found at each stage, are in accordance with what has been recorded for temperate populations. In our study, the planktonic stage was found to be of shorter duration than elsewhere, which might be associated with the higher temperatures at which larvae were cultured compared to previous studies.     

Using Action Research to Implement Selective Waste Collection Program in a Brazilian City

The objective of this paper is to study and report upon the elaboration of a selective waste collection program in a Brazilian city through action research; the overarching goal is that all knowledge generated may serve as a basis of information and reference to aid in decision making for similar programs globally. The municipality chosen was São Lourenço in the state of Minas Gerais. The implementation of the selective waste collection program happened over the course of multiple improvement and learning cycles, and enabled many environmental, economic and social benefits for all of the project’s stakeholders. Eighty-nine tons of potentially recycled material were sent to recycling processes rather than being disposed of in a landfill. No great difficulties were observed for the use of action research as a method, but some challenges were encountered and overcome during the whole process, due to the lack of structure and confidence on part of the population, in relation to the selective collection program. The choice for action research as the methodology and the use of improvement and learning cycles proved to increase the project’s overall efficiency, making it possible to make decisions more quickly, generating better results, and enabling replications of good decisions and correction of errors from one cycle to the next.     

关于图书馆员职业精神的思考

论述了职业精神是道德建设的内核,介绍了图书馆员职业精神的内涵,并就馆员职业精神的培养提出了一些具体措施。     

群体决策的一类惩罚评分方法

引进群体决策中关于评分数的惩罚因子 ,由此定义了惩罚评分数和惩罚评分泛函概念 .在研究了从个体惩罚评分泛函到群体惩罚评分泛函的惩罚评分映射有关性质的基础上 ,构造了一类求解群体决策的惩罚评分方法 .     

浅谈对曝光新闻的正确认识——由几次“流产报道”想到的

通过对曝光新闻概念的界定；对曝光新闻的最终目的、对象的把握；对曝光新闻的社会环境、舆论作用的讨论，阐述了如何正确认识曝光新闻的问题。     

一种高效三唑除草剂的合成及应用

合成了一种高效除草剂[1] ,化学名称 :1,2 ,4—三唑— 3—磺酸—二乙基甲酰胺— 2 ,4,6—三甲基酚酯 ,采用熔点测定、元素分析、红外和核磁分析等手段鉴定了它的结构 ,并对其进行详细的生物活性测定 ,显示出良好的除草活性及较高的选择性     

随机性死机故障分析与排除

死机故障是电脑使用过程中一种常见故障 ,而随机性死机由于出现死机的故障不确定 ,所做操作性质不固定 ,而且死机发生时 ,显示的现象也不统一 ,所以随机性死机产生的原因相当复杂。本文通过对大量的维修实例的分析 ,总结出随机性死机故障产生的主要原因 ,提出了随机性死机故障的分析与维修方法。