稻麦轮作田氮素径流流失特征初步研究

针对近年来氮素化肥施用量大而利用率较低现状，在江苏太湖地区设计田间试验，研究稻麦轮作田全年氮素流失特征。结果表明，在本试验条件下稻季和麦季径流中氮损失量相近，麦季略高，约占施氮量的2％左右。麦稻轮作田径流氮损失中氨态氮较少，以硝态氮和其他形态氮为主，其中氨态氮损失以稻季为主，硝态氮损失稻季和麦季相近，其他形态氮损失麦季较多。不同作物田径流氮组成存在差异，麦季径流氮以硝态氮和其他形态氮为主，氨态氮极少，而稻季在施肥后短时间内径流氮中氨态氮、硝态氮和其他形态氮大致相当，其他时间以硝态氮和其他形态氮为主。     

The Role of Hybrid Vigor in the Replacement of Pecos Pupfish by Its Hybrids with Sheepshead Minnow

Abstract:  Many species are jeopardized by hybridization and genetic introgression with closely related species. Unfortunately, the mechanisms that promote or retard gene flow between divergent populations are little studied and poorly understood. Like many imperiled fish species, the Pecos pupfish ( Cyprinodon pecosensis ) is threatened with replacement by its hybrids with a close congener. We examined swimming performance and growth rate of hybrid pupfish to determine the role of hybrid vigor in the genetic homogenization of C. pecosensis by its hybrids with sheepshead minnow ( C. variegatus ). The F1 hybrids, backcross hybrids, and purebred C. variegatus displayed greater swimming endurance than purebred C. pecosensis . In addition, F1 hybrids and C. variegatus grew more rapidly than C. pecosensis . The ecological superiority of hybrids probably promoted their rapid spread through and beyond the historic range of C. pecosensis . These results indicate that eradication of hybrids and restoration of C. pecosensis to its native range is unlikely. Extinction of unique species via genetic homogenization can result from human activities that increase gene flow between historically fragmented populations; conservation managers must weigh the potential for such a catastrophe against the presumed benefits of increased interpopulation gene flow. This example illustrates how, after hybridization has occurred, conflict may arise between formerly complementary conservation goals.     

流动注射-化学发光流通池芯片及其在环境污染物测定中的应用

1　IntroductionMiniaturizationofanalyticalsystemhasbeenpaidmuchattentiontointherecentyearsforitsobviousadvantages:fastanalysis,portability,reducedconsumptionofreagentsandimprovingper formance .Suchdeviceisso calledaslaboratory on a chip[1 ],whichistheinte…     

蓟县水资源状况分析

在蓟县水资源调研基础上，对蓟县水资源状况和利用情况进行了分析。     

Modeling Free-Surface Fluctuation Effects for Calculation of Turbulent Open-Channel Flows

A new method of introducing the free-surface effects in the calculation of turbulent open-channel flows using the amplitude of the free-surface fluctuation is proposed along with a modeling method of the equation for the free-surface fluctuation. It can be incorporated in two-equation models like k-or k-type models by introducing the damping factor to represent the interaction of the eddies with the fluctuating free-surface. Test calculations for fully developed flows and those over backward-facing step indicate good agreement with direct numerical simulation results as well as experimental results.     

炼油厂污泥脱水系统技术改进

阐述炼油厂污水处理场污泥的组成、性质及污泥脱水的实际情况，在原工艺处理流程的基础上采取增加污泥储存罐、污泥调理系统、污泥输送系统等设施，并进行一系列的技术改造，使得污泥脱水系统能够正常平稳运行，减少污泥对环境的污染．取得了一定的经济效益和社会效益。     

铅锌冶炼企业循环经济建设中的物质流分析方法研究

针对循环经济建设模式下有色金属行业企业循环经济建设的物质流分析的特点,对铅锌冶炼企业物质流动情况,从分析方法的内容与步骤两方面进行了详尽的研究,得到了适用于铅锌冶炼企业循环经济建设的物质流分析方法,即采用生命周期评价方法对铅锌冶炼主流程各工序的物质流进行分析,用化合物物质流分析方法进行铅锌伴生元素回收过程的输入输出分析.     

流动注射催化光度分析法的研究进展

综述了近年来流动注射催化光度分析法的研究进展，包括环境水样中金属离子、阴离子、有机物等污染物的测定，展望了流动注射催化光度分析法未来的研究方向和发展前景。     

强化A2/O工艺反硝化除磷性能的运行控制策略

以啤酒废水为研究对象,重点考察了如何强化A2/O工艺反硝化除磷性能,从而提高营养物去除效果、并实现节能的目的.试验中建立了3种运行控制策略:(1)根据缺氧区末端出水硝酸盐的浓度控制内循环回流量;(2)调节厌氧/缺氧/好氧区体积比以减少厌氧区出水剩余COD对缺氧磷吸收的影响;(3)向缺氧区引入旁流并调节旁流比.试验结果表明,当缺氧区末端出水硝酸盐浓度控制在1～3 mg·L-1时,不仅可强化反硝化除磷效果,而且可以节省内循环所需能耗;厌氧/缺氧/好氧区最佳体积比为1/1/2;旁流的引入可以提高低C/N比条件下TN的去除,最优旁流比为0.32.     

云南省德钦县泥石流特征及成因分析

德钦县由于其特殊的地质环境,泥石流活动频繁,严重影响了当地人民的生命、财产安全和经济发展。本文主要论述了德钦县泥石流的特征以及从地貌、地质构造、气候、水文、植被、不合理的人类工程活动等方面阐述了泥石流的成因,以便人们了解泥石流的形成机理,从而达到防灾减灾的目的。