我国精密可控震源主动探测研究进展

精密可控震源对地发射扫频信号,通过高精度的观测系统获得记录资料,采用专门的数据处理方法来提取信号,获得地下介质的信息。介绍现有的一些数据处理方法,比如匹配滤波、反褶积、Wigner-Hough变换和时变滤波等,可以实现可控震源信号提取。并总结这些方法的优缺点。通过多次野外科学实验发现,精密可控震源技术是一种探测地下介质结构及变化的有效途径。针对精密可控震源探测的影响因素,还需要开展深入研究,以便于改善其探测距离和分辨能力。     

生物质炭对邻苯二甲酸二丁酯污染土壤微生物群落结构多样性的影响

在邻苯二甲酸二丁酯(DBP)污染的不同类型土壤(有机质含量低的新垦红壤、有机质含量高的熟化红壤)中添加不同种类(稻草炭、毛竹炭)以及不同用量(0%、0.5%和2%)的生物质炭,温室种植上海青并在56 d后采集土样,采用磷脂脂肪酸法(PLFA)考察了土壤类型、生物质炭种类以及用量对土壤微生物群落结构多样性的影响.结果表明:对细菌、真菌及微生物总PLFA这三者的含量而言,熟化红壤显著(p0.05)高于新垦红壤,熟化红壤中添加2%稻草炭使其显著(p0.05)增加,新垦红壤中添加毛竹炭使其显著(p0.05)降低.新垦红壤中添加2%稻草炭对革兰氏阴性菌/革兰氏阳性菌比值的增加效果最显著(p0.05),添加2%毛竹炭对土壤微生物群落Shannon指数的降低效果最显著(p0.05).添加2%稻草炭对DBP污染土壤中微生物压力指数降低效果最显著(p0.05).生物质炭对熟化红壤中真菌/细菌、革兰氏阴性菌/革兰氏阳性菌及微生物群落Shannon指数均无显著影响.PCA分析表明,土壤有机质含量以及生物质炭的种类和用量均会对土壤微生物群落结构产生一定影响,且生物质炭的影响与土壤有机质含量密切相关.     

土体-结构界面接触对地下结构动力反应的影响

迄今为止,关于土体与结构交界面的接触效应对地下结构地震反应的影响尚未引起研究者们的重视,成果鲜有报道。本文基于接触面对法和非线性有限元波动分析方法,建立了考虑土体与结构界面接触效应的地下结构非线性地震反应分析模型和计算方法,并利用大型有限元软件ANSYS进行了求解。分析结果表明:土体与结构界面的接触效应对地下结构地震反应有明显影响,可能增大地下结构节点的峰值加速度、峰值位移和峰值应力反应;随着接触摩擦系数的增大,接触点的相对滑移逐渐减小,而接触应力的变化则无明显规律。     

Effects of Pond Draining on Biodiversity and Water Quality of Farm Ponds

Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large‐scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond‐management practices, pond physicochemistry, and surrounding land use. The results of boosted regression‐tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo     

高层RC框架结构基于成本-效益准则的优化设计研究(Ⅱ)——应用

根据作者先前提出的优化模型及基于成本-效益准则的优化设计流程,以多目标遗传算法为搜索引擎,运用MATLAB语言开发了高层RC框架结构基于成本-效益准则的自动优化程序。研究结果表明,程序所产生的设计方案具有多样性、可选择性、业主主动参与性及可依靠经验等特点。     

Analysis of landscape pattern: towards a ‘top down’ indicator for evaluation of landuse

Landscapes as highly complex systems are subject to many different assessment procedures despite the fact that their development is not really predictable. Every synthetic model of landscape functioning will probably fail in demonstrating the landscape behaviour due to the decreasing precision and relevance of its output with increasing complexity. Two approaches are presented here which use deductive methods to describe landscape behaviour as indicated by its spatial structure. The one is a correlative concept which is characterized by all the advantages and disadvantages of statistical regression methods. It is strongly dependent on data quality. In the second study an expert knowledge system is developed. Fuzzy set theory is applied to transfer rules of landscape ecological experience to image parameters derived from satellite data. Both approaches are compared regarding the problems faced in the work during implication. Theoretical restrictions and the applicability in landscape assessment is discussed.     

Personal need for structure as a boundary condition for humor in leadership

Recent research has established a positive relationship between humor in leadership and organizational behavior variables. However, neither the mechanisms nor the boundary conditions of the positive effects of humor in leadership are completely understood. In this study, we contribute to these questions by investigating the relationship between humor in leadership and follower commitment and burnout in more detail. We propose that these relationships unfold via a relational process and specified this relational process in terms of leader–member exchange. Moreover, we assume that these relationships depend on followers' personal need for structure. We tested the hypothesized moderated‐mediation model in a two‐wave survey study with 142 employees. Our results support the proposed model. We found the predicted indirect effect of humor on commitment and disengagement to be stronger for followers low in need for structure. However, we did not find the proposed effects for emotional exhaustion. We discuss implications for leadership theory, humor theory, and for leadership training and practice. Copyright © 2016 John Wiley & Sons, Ltd.     

随机地震激励下相邻隔震结构被动控制研究

利用隔震结构和非隔震结构间的相互作用来减小地震作用下的结构响应,考虑地震激励的随机性,基于Clough-Penzien谱模型,推导了相邻结构随机响应的拓展状态方程,采用两种优化控制目标,分析得到了相邻隔震结构体系间连接控制装置的控制参数与结构随机响应的关系及其对控制效果的影响,并分别从地震响应时程和振动累计能量时程角度研究了相应地多自由度相邻隔震结构复合被动控制体系,在不同优化准则及不同控制方案下,结构体系的减震控制效果。研究结果表明,相邻隔震结构复合被动控制体系,可以获得较好的减震控制效果,阻尼系数在减震控制中起主要作用,但存在最优取值,并不是越大越好;采用以左、右子结构振动总能量最小为优化准则,在顶层+中间层安装控制装置的控制方案,可以有效地减小相邻结构的地震响应,得到的控制效果较好。     

天津大港发电厂附近海域浮游植物群落结构及与环境因子的相关性

为了解电厂温排水和人海河流对浮游植物群落结构的影响,于2010年对大港电厂附近海域浮游植物和环境因子开展了冬、夏2个航次的调查,探讨了浮游植物群落结构时空分布特征及与环境因子的关系.结果表明,调查区共鉴定出浮游植物4门31属46种,其中硅藻在物种组成和细胞密度上均具有绝对优势.调查区浮游植物种群结构简单,组成相对稳定,细胞密度全年平均为729×107个/m3,高于渤海其他海域,且冬季数量高于夏季.受温排水和人海河流影响,浮游植物平面分布具有明显的空间效应和季节变化特征,呈近岸区高于远岸区的分布趋势.近岸站位TJHS1101和TJHS1117分别受人海营养盐和温排水的影响,夏、冬季呈现不同的分布特征.研究表明,浮游植物在夏季的限制性生长因子是可溶性无机氮,冬季是PO43--P;水温、NO2--N和NH4+-N是影响浮游植物空间分布的主要环境因子;盐度、pH值和DO.对浮游植物的影响表现出季节性差异.