A combo technology of autotrophic and heterotrophic denitrification processes for groundwater treatment

In this study,a sequential process (heterotrophic up-flow column and completely mixed membrane bioreactors) was proposed combining advantages of the both processes.The system was operated for 249 days with simulated and real groundwater for nitrate removal at concentrations varying from 25 to 145 mg·L-1 NO3-N.The contribution of heterotrophic process to total nitrate removal in the system was controlled by dozing the ethanol considering the nitrate concentration.By this way,sulfur based autotrophic denitrification rate was decreased and the effluent sulfate concentrations were controlled.The alkalinity requirement in the autotrophic process was produced in the heterotrophic reactor,and the system was operated without alkalinity supplementation.Throughout the study,the chemical oxygen demand in the heterotrophic reactor effluent was (23.7 ± 22) mg·L-1 and it was further decreased to(7.5 ± 7.2) mg·L-1 in the system effluent,corresponding to a 70％ reduction.In the last period of the study,the real groundwater containing 145 mg·L-1 NO3-N was completely removed.Membrane was operated without chemical washing in the first 114 days.Between days 115-249 weekly chemical washing was required.     

一种无线传感器网络匿名安全路由协议*

为了能在有限资源的无线传感器网络上进行安全的匿名通信,使用双线性函数的双线性对和异或运算提出了一种匿名安全路由协议,与目前现有的无线网络匿名通信方案相比,协议不仅能提供身份的机密性、位置隐私性和路由的匿名性,而且还满足前向和后向安全性,并且大大提高了系统的计算复杂度和带宽消耗,更适合无线传感器网络。     

多媒体会议系统解决方案(二)

3多传声器同时使用的自动控制系统 3．1 应用环境特点 在扩声工程中要求“同时使用的传声器数量越少越好”。2支以上传声器如果在一个声场中同时工作，不仅存在相位干扰，且极易产生啸叫，传声增益大为降低，噪声也会大量增加，系统整体信噪比指标严重跌落。     

一类线性矩阵方程的最佳逼近解

本文利用投影定理、广义奇异值分解和标准相关分解技巧给出了一种求矩阵方程AXB=C的最小二乘反对称解的方法,得到了通解表达式。进而利用此表达式,导出了通解集做为一个矩阵集与任意给定矩阵的最小距离元素。     

基于GIS的南宁市邕江流域水环境管理决策支持系统的开发和应用

针对南宁市水环境质量问题和管理需求,基于GIS系统的三级数据架构体系,开发设计了南宁市邕江流域水环境管理决策支持系统,并模拟计算了2013年南宁市邕江及其18条支流各监测点的水量、水质指标值。结果表明,计算指标值与实测指标值基本一致,预测精度较高,该系统实现了流域信息的可视化及水量水质的动态模拟,为南宁市水环境整治工程的开展提供了有效决策支持,为其他水环境管理系统的开发提供了参考。     

机床导轨的振动挤光

振动挤光工艺,方法简单,适用于包括维修在内的一切加工生产过程。本文研究的是振动挤光机床导轨的最佳工艺条件。 采用这种工艺所得到的表面微观轮廓是千变万化的,所以给振动挤光机床导轨表面的研究带来了许多困难。但是这种表面微观轮廓特性可以通过控制工艺参数来确定。首先控制振动钢球的直径;其次控制施加于钢球上的压力(在特定的极限范围内),以及控制钢球在平面上走过的轨迹,钢球轨迹根据振动头的工作条件和工件进给量来确定。 在钢球振动挤光表面的过程中,接触处产生金属塑性变形,从而其表层也被硬化了。因此,可在塑性变形最大处测量…     

极高等级

费城有了新的标志：罗伯特·A·M·斯特恩事务所（Robert A．M．Stern Architects）设计的一座975英尺高的晶面玻璃塔。对于这座温文尔雅的城市来说，这座塔有着惊人的高度和蛊惑人心的性感，但当游客们大踏步的走过塔下闪烁着灰绿色光芒的花岗岩广场时．却极有可能留意不到那美观优雅的注明了主要租户公司的标识牌。     

罗马尼亚外国投资的现状

罗马尼亚商务立法制度对外国投资者非常有列，允许外国投资者拥有100％的所有权，允许将利润与资本转向国外，也允许减免税收。根据1990年31号公司法的规定，外国投资者可以在罗建立新公司或分公司，全部外资或合资，法人或自然人。凡在罗投资者，需向罗开发局提出申请，罗开发局收到申请后应在30天内予以答复，在此期间未收到答复，则视为批准。外国投资者在罗可享受各种优惠：外资既可投向各工业部门，也可投向农业、基础设施、交通运输、工民建、科技开发、贸易、旅游、银行、保险等；外国投资者所获合法利润可以自由转换成货币输出国外：按合同条款规定，还可向国外转让版权、技术和其他服务项目；外资在罗将不会国有化，不会征用，不会剥夺所有权；根据法律规定及合同条款，外国投资者有权参加投资管理；外国投资者可以免征海关进口税等。当然，外国投资者必须遵守罗马尼亚的有关法律，特别是不允许违反环境保护法，不允许影响罗马尼亚的国家安全与国防利益，不允许危害公共秩序、健康与道德规范。     

In situ spectroelectrochemistry of poly(N,N'-ethylenebis(salicylideneiminato)Cu(II))

In situ ESR, UV-visible, and FT-IR-ATR spectroelectrochemistry were used to study the charge transfer for electrochemically synthesized poly(N,N'-ethylenebis(salicylideneiminato)Cu(II)), which represents a macromolecular metal chelate with ESR-active central metal ions. Structural evidence for different charged states in electroactive poly(Cu(II)-salen) was obtained from ESR, UV-visible, and FT-IR spectra under reversible redox cycling. The changes in a characteristic broad ESR line without hyperfine splitting originating from Cu(II) as well as in the corresponding UV-visible and infrared spectra are discussed in order to describe an electron transfer to the redox-active sites within the polymer chains in detail.     

Structure-based design of inhibitors of NS3 serine protease of hepatitis C virus

We have designed small focused combinatorial library of hexapeptide inhibitors of NS3 serine protease of the hepatitis C virus (HCV) by structure-based molecular design complemented by combinatorial optimisation of the individual residues. Rational residue substitutions were guided by the structure and properties of the binding pockets of the enzyme's active site. The inhibitors were derived from peptides known to inhibit the NS3 serine protease by using unusual amino acids and alpha-ketocysteine or difluoroaminobutyric acid, which are known to bind to the S1 pocket of the catalytic site. Inhibition constants (Ki) of the designed library of inhibitors were predicted from a QSAR model that correlated experimental Ki of known peptidic inhibitors of NS3 with the enthalpies of enzyme-inhibitor interaction computed via molecular mechanics and the solvent effect contribution to the binding affinity derived from the continuum model of solvation. The library of the optimised inhibitors contains promising drug candidates-water-soluble anionic hexapeptides with predicted Ki* in the picomolar range.