长江中下游河道与岸线演变特点

分析了长江中下游河道岸线变化的主要因素，它们分别是河岸崩塌，泥沙淤积及人类活动等，其中河岸崩塌是河道岸线演变的最主要原因。总的来说长江中下游干流河势是稳定的，但五个河段有各自演变特点和规律，其中宜昌－枝城段河道与河床比较稳定，岸线顺直，但葛洲坝和三峡水利枢纽建成后对河床的冲刷作用较大；荆江段是长江著名的河曲段，其冲淤变化较大；城陵矶至湖口段为节点和分汊河床组成，一般来说节点较为稳定，而分汊河床不太稳定，湖口至江阴河段岸线一般较为稳定，但弯道河床变化较大；河口段不但受江流作用影响，还受潮流与波浪等共同影响，所以河口河床演变迅速，主要表现为汊道主泓迁移摆动。     

斜坡失稳的动力学分析

本文从岩土破坏的本构律出发建议了斜坡失稳的滑动—弱化模式,然后对平面倾斜面、幂函数型滑动面、园弧型滑动面等简单的情形进行了斜坡失稳的动力学分析,得到了滑坡速度分布的表示式:讨论了坡底速度、滑坡止滑位置等问题。     

采用跟踪控温近似绝热系统测定火炸药热爆炸参数的探讨

本文针对以往在火炸药热爆炸参数测试过程中，因试样与加热介质之间的热交换所带来的较大测试误差，建立了跟踪控温下的近似绝热测试系统，研制了本测试系统的中枢仪器──四通道数显温度调节自动跟踪仪。通过本测试系统的建立，使得对热爆炸参数的测试更具有科学性和实用性。     

Kelvin–Helmholtz Instability as a Boundary-Value Problem

The Kelvin–Helmholtz (KH) instability is traditionally viewed as an initial-value problem, wherein wave perturbations of a two-layer shear flow grow over time into billows and eventually generate vertical mixing. Yet, the instability can also be viewed as a boundary-value problem. In such a framework, there exists an upstream condition where a lighter fluid flows over a denser fluid, wave perturbations grow downstream to eventually overturn some distance away from the point of origin. As the reverse of the traditional problem, this flow is periodic in time and exhibits instability in space. A natural application is the mixing of a warmer river emptying into a colder lake or reservoir, or the salt-wedge estuary. This study of the KH instability from the perspective of a boundary-value problem is divided into two parts. Firstly, the instability theory is conducted with a real frequency and complex horizontal wavenumber, and the main result is that the critical wavelength at the instability threshold is longer in the boundary-value than in the initial-value situation. Secondly, mass, momentum and energy budgets are performed between the upstream, unmixed state on one side, and the downstream, mixed state on the other, to determine under which condition mixing is energetically possible. Cases with a rigid lid and free surface are treated separately. And, although the algebra is somewhat complicated, both end results are identical to the criterion for complete mixing in the initial-value problem.     

五里塘生态农场有机废弃物的资源化生态工艺

上海市松江县五里塘生态农场以沼气工程、氧化沟和鱼塘围网养鸭为主的生态工程,有效地利用了农场产生的大量禽畜粪便并解决了沼液,沼渣的二次污染问题;在沼气池上建玻璃温室保温,使沼气池能正常越冬从而得以周年运转.生态工程的建立,取得了良好的经济、生态和环境效益.     

长江水域强制铺设围油栏的必要性和实施对策

针对长江干线推行强制铺设围油栏工作中存在的问题，提出这项工作的必要性以及解决的对策。     

明渠中有机质微粒沉降过程的随机游走模拟

基于明渠流动的主要特点,考虑紊动强度的垂向非均匀性,及颗粒运动的游荡效应（loitering effect）影响,对微粒运动基本方程进行改进,建立了明渠非均匀紊流中考虑游荡效应的随机游走模型,对明渠中微粒的沉降损失进行了模拟分析.模拟结果显示,不考虑游荡效应影响时,明渠中微粒的沉降损失率可用微粒沉速与水深之比计算;而在游荡效应影响下,微粒沉降损失率会发生约18%~27%的下降,下降百分比与均匀紊流中微粒沉速在游荡效应影响下的折减百分比渐近值（19~25%）基本一致.本文结论基于不考虑微粒重悬浮、游荡效应为紊流对微粒沉降的主导影响机理等前提,主要适用于对明渠中细小有机质微粒沉降至床底过程更准确的计算分析.     

汶川地震灾区小流域洪水计算方法初探

汶川地震灾区小流域山洪不仅造成巨大损失,同时也是泥石流等灾害的激发因素,探寻一种准确且可操作的洪水峰值流量计算方法对防灾减灾具有重要意义。本文选择不同产流和汇流计算方法,组合成不同水文模型,进行小流域洪水过程计算,对模拟结果和参数选择进行对比,旨在探究最适合该地区的小流域水文计算方法。分别选择SCS曲线法、Green-Ampt入渗法、初损稳渗法进行坡面产流计算,应用SCS单位线法、Snyder单位线法和运动波方程进行坡面和沟道汇流计算,组合成5种小流域产汇流计算模型,利用6场洪水进行参数率定和结果验证。模拟结果对比分析,得出SCS曲线法是最适宜的产流模型,其与SCS单位线、运动波汇流计算方法组合而成的SCS和SKK模型,峰现时间的模拟误差最小,在0~25 min之间;洪峰流量模拟的相对误差较小,平均误差不超过4%;洪水总量模拟误差在10%左右。另外,这两种模型参数设置及确定较简单,更适合在数据稀缺的小流域中进行洪水模拟应用。研究可为汶川地震灾区小流域山洪和泥石流等灾害的流量估算提供方法和参数借鉴。     

微波消解-双道原子荧光分析仪联合测定土壤中砷和汞

应用AFS-9530型双道原子荧光光谱法研究土壤样品中砷和汞的联合测定技术,将土壤样品置于(1+1)王水的微波消解体系中进行消解,加入1m L 5%的重铬酸钾溶液保护汞,加入5m L(5%硫脲+5%抗坏血酸)混合液将五价砷还原为三价,以硼氢化钾为还原剂在5%盐酸介质中测定砷和汞,最低检出限为砷0.55μg/L,汞0.30μg/L,回收率砷在93.5%—105.8%之间,汞在85.5%—104.9%之间,满足准确度要求。     

Effects of Two Amphibian Pathogens on the Developmental Stability of Green Frogs

Abstract: Developmental instability, measured as fluctuating asymmetry (FA), is often used as a tool to measure stress and the overall quality of organisms. Under FA, it is assumed that control of symmetry during development is costly and that under stress the trajectory of development is disturbed, resulting in asymmetric morphologies. Amphibian emergent infectious diseases (EIDs), such as Ranavirus and chytrid fungus, have been involved in several mortality events, which makes them stressors and allows for the study of FA. We analyzed nine populations of green frogs (Rana clamitans) for the presence or absence of Ranavirus and chytrid fungus. Individuals were measured to determine levels of FA in seven traits under the hypothesis that FA is more likely to be observed in individuals infected by the pathogens. Significantly higher levels of FA were found in individuals with Ranavirus compared with uninfected individuals among all populations and all traits. We did not observe FA in individuals infected with chytrid fungus for any of the traits measured. Additionally, we observed a significant association between Ranavirus infection and levels of FA in both males and females, which may indicate this viral disease is likely to affect both sexes during development. Altogether, our results indicate that some EIDs may have far‐reaching and nonlethal effects on individual development and populations harboring such diseases and that FA can be used as a conservation tool to identify populations subject to such a stress.