SnO2-montmorillonite composite for removal and inhibition Microcystis aeruginosa assisted by UV-light

Cyanobacterial blooms have become a serious pollution problem,in particular,for water resources.Microcystis aeruginosa(M.aeruginosa)is most common toxic cyanobacterial bloom in fresh waters.In this paper,Sn O_2-montmorillonite composite was prepared by ion exchange method and applied to remove M.aeruginosa with the assistance of UV-light.The structure of the resulting composite was identified by XRD,IR and TEM.It was determined that some Sn O_2nanoparticles were inserted into the interlayer of montmorillonite and some were dispersed on the surface of montmorillonite.M.aeruginosa removal efficiency was judged by the rate of 95%after treatment with 0.3 g/L Sn O_2-montmorillonite for 1 h.Sn O_2-montmorillonite composite absorbed M.aeruginosa and promoted M.aeruginosa lysis by damaging cell wall and membrane.The cellular contents,including protein and chlorophyll a,were then degraded with the assistance of UV-light,which inhibited the biological activity of M.aeruginosa.In fact,Sn O_2-montmorillonite composite removed M.aeruginosa by combination of adsorption flocculation and UV-induced catalytic degradation.Sn O_2-montmorillonite shows promise to become an effective material for the removal of algae and the cyanobacteria bloom.     

红外对射的无线发射新型智能红外报警系统

针对安防技术不断发展的现状,利用红外线隐蔽性高、保密性高、抗干扰能力强等特点,设计了一种红外报警系统,该系统利用声光报警器、红外线对射管、单片机等设计了报警器驱动电路、电压驱动电路等部分.通过红外对射管继电器的开闭情况经放大处理后传送给单片机,经过单片机的处理通过放大驱动电路智能控制红外报警器的状态;此外,通过无线发射模块可以将现场是否发生报警的情况传到上位机.试验结果表明:该红外报警系统可以快速有效地实现上述所有功能,达到保护生产生活安全的目的.     

室内给水管网的数学模型分析

本文采用有限元法分析了室内给水管网的运行状况,提出了求解管网的数学模型,统一了环状网络和枝状肉络的水力计算方法。实例表明,采用本文提供的数学模型编制的水力计算程序,具有计算步骤少、迭代次数少和易于掌握的特点.     

3种转化人参皂苷CK菌群的结构与多样性

目的 探讨人参栽培地3种土壤中获得的高效转化人参皂苷CK菌群的群落结构与多样性.方法 采用高通量测序技术分析高效转化人参皂苷CK的微生物群落组成.结果 3种能够高效转化人参皂苷CK的菌群中以子囊菌门(Ascomycota)为主,其相对丰度为14.7％～38.1％.同时在3种菌群中还含有少量的接合菌门(Zygomycot...     

热障涂层热循环过程中的界面扩散系数

采用磁控溅射力方法在镍基单晶高温合金基体上沉积Ni-30Cr-12Al-0．3Y(质量分数，％)粘结层，采用电束物理气相沉积方法(EB-PVD)沉积7％Y2O3(质量分数，％ZrO2)陶瓷层．对粘结层与陶瓷层界面在1050℃循环100次时的元素扩散，提出了电子探针与最小二乘法相结合的研究方法．求出元素在界面的扩散系数．继续热循环，粘结层中Al贫化．Ni和Cr参与氧化，加速氧化反应，增加氧化膜内应力，使氧化膜破裂、陶瓷层剥落，最终导致热障涂层失效。     

一种基于神经网络的事例相似度评估方法

提出一种基于分布式神经网络的事例相似度评估的体系结构及实现方法 ,即通过输入新旧事例中特征之间的两两相似度 ,利用神经网络来确定新旧事例之间的综合相似度 ,以此来改善不良结构决策领域中基于事例推理系统的事例检索性能     

利用VC++编程实现防火墙数据包过滤

随着计算机网络深入社会、经济、国防、科技与文教等各个领域 ,计算机系统的安全问题正变得日益复杂和突出 .资源共享和网络分部更增加了网络收到威胁和攻击的可能性 ,于是基于包过滤加状态检测的防火墙系统成为保护网络安全的工具 .文中介绍一种集数据包过滤、日志、代理服务于一体的复合型防火墙系统 ,着重论述利用 VC 编程技术实现数据包过滤的软件方法 .     

电压型PWM整流器直接功率控制系统主电路参数设计

为了解决电压型PWM整流器直接功率控制系统主电路参数设计问题,根据整流器在dq两相同步旋转坐标系中的数学模型建立了其功率控制数学模型. 基于功率控制数学模型,结合整流器直接功率控制系统的特点,推得交流侧电感是由功率、功率滞环比较器环宽及开关平均频率决定的;直流侧直流电压是由交流电压、电感及负载决定的;突加负载时直流侧电容是由直流电压波动、功率、电感及负载决定的. 根据上述影响主电路参数的诸多因素,提出交流侧电感、直流侧电压及直流侧电容的设计方法. 计算机仿真和实验证明了本文提出的设计方法是可行的.     

Low European methyl chloroform emissions inferred from long-term atmospheric measurements

Methyl chloroform (CH3CCl3, 1,1,1,-trichloroethane) was used widely as a solvent before it was recognized to be an ozone-depleting substance and its phase-out was introduced under the Montreal Protocol. Subsequently, its atmospheric concentration has declined steadily and recent European methyl chloroform consumption and emissions were estimated to be less than 0.1 gigagrams per year. However, data from a short-term tropospheric measurement campaign (EXPORT) indicated that European methyl chloroform emissions could have been over 20 gigagrams in 2000 (ref. 6), almost doubling previously estimated global emissions. Such enhanced emissions would significantly affect results from the CH3CC13 method of deriving global abundances of hydroxyl radicals (OH) (refs 7-12)-the dominant reactive atmospheric chemical for removing trace gases related to air pollution, ozone depletion and the greenhouse effect. Here we use long-term, high-frequency data from Mace Head, Ireland and Jungfraujoch, Switzerland, to infer European methyl chloroform emissions. We find that European emission estimates declined from about 60 gigagrams per year in the mid-1990s to 0.3-1.4 and 1.9-3.4 gigagrams per year in 2000-03, based on Mace Head and Jungfraujoch data, respectively. Our European methyl chloroform emission estimates are therefore higher than calculated from consumption data, but are considerably lower than those derived from the EXPORT campaign in 2000 (ref. 6).     

考虑负摩阻力的回填土地基单桩承载力计算

回填土地基的桩基设计若忽略负摩阻力的影响,将使设计有不安全因素。根据负摩阻力产生条件和作用机理,通过现场静载荷实验,研究了考虑负摩阻力的回填土地基中端承桩单桩承载力计算问题。实例分析表明,由于桩侧负摩阻力的影响,单桩承载力大为降低。产生负摩阻力的土层,不宜采用端承型桩基。该结果可为回填土地基的桩基设计提供理论依据。