城市雨水管网水力学计算方法研究

根据城市雨水管网的特点，推导了雨水管道非恒定非均匀流的偏微分方程组，并给出了管道初始条件和边界条件．介绍了对于雨水管网求解方程组的方法和一些实用简化模型．     

膜分离技术在电镀镍漂洗水回收中的应用

经过一系列的实验 ,证明了采用膜分离技术浓缩电镀镍漂洗水和回收利用漂洗水中的镍和水资源的可行性 .实验结果表明 ,NF技术对镍离子的截留率大于 97% ,RO技术对镍离子的截留率大于 99% .对于镍离子浓度为 14 5mg/L的进水 ,膜分离技术可浓缩电镀镍漂洗水 10 0倍以上 ,经一级NF ,两级RO(BWRO、SWRO)浓缩 ,浓缩液镍离子浓度可达到 5 0 g/L ,透过液经处理后回用     

A pilot-plant study of the adsorptive micellar flocculation process: Optimum design and operation

A pilot-plant scale study of the adsorptive micellar flocculation (AMF) process is presented for the first time, and builds on the solid foundation provided by previous fundamental laboratory studies. A number of experimental tests were conducted to validate the feasibility of using an AMF pilot rig to remove phenol from aqueous effluent streams. Several key factors, including flocculation time, floc settling time, optimum air flow-rate for agitation, and flocculant dosage, were determined. Residual concentrations in treated water indicated a surfactant removal efficiency of 95–98%, and pollutant removal reached 78% in two stages of process operation. A strategy for the separate recycling of surfactant, flocculant and pollutant has already been developed. The present study has thus made further progress in developing, testing, validating and optimising the operating conditions of a pilot-scale process. As such, it has demonstrated the feasibility of scaling up from the bench-scale to a commercial, continuously operated unit.     

Integrating domain knowledge,requirements, and specifications

This paper describes efforts to develop a transformation-based software environment that supports the acquisition and validation of software requirements specifications. These requirements may be stated informally at first, and then gradually formalized and elaborated. Support is provided for groups of requirements analysts working together, focusing on different analysis tasks and areas of concern. The environment assists in the validation of formalized requirements by translating them into natural language and graphical diagrams and testing them against a running simulation of the system to be built. Requirements defined in terms of domain concepts are transformed into constraints on system components. The advantages of this approach are that specifications can be traced back to requirements and domain concepts, which in turn have been precisely defined.     

Domain-oriented design environments

The field of knowledge-based software engineering has been undergoing a shift in emphasis from automatic programming to human augmentation and empowerment. In our research work, we support this shift with an approach that embedshuman-computer cooperative problem-solving tools intodomain-oriented, knowledge-based design environments. Domain orientation reduces the large conceptual distance between problem-domain semantics and software artifacts. Integrated environments support the coevolution of specification and construction while allowing designers to access relevant knowledge at each stage within the software development process.This paper argues thatdomain-oriented design environments (DODEs) are complementary to the approaches pursued withknowledge-based software assistant systems (KBSAs). The DODE extends the KBSA framework by emphasizing a human-centered and domain-oriented approach facilitating communication about evolving systems among all stakeholders. The paper discusses the major challenges for software systems, develops a conceptual framework to address these problems, illustrates DODE with two examples, and assesses the contributions of the KBSA and DODE approaches toward solving these problems.     

Gbit／s高速网络及其CRMA MAC协议

本文介绍了易于信元交换的ＡＴＭ技术和Ｂ－ＩＳＤＮ接轨的基于时间槽的Ｇｂｉｔ／ｓ高速网络及其ＭＡＣ协议ＣＲＭＡ，描述了ＣＲＭＡ传统模式，新的按节点划分区域时间槽重复使用的ＦＲ预约模式，进一步改善了网络性能。     

Transient identification of defective trap seals

The prevention of the ingress of contaminated air into habitable spaces has been a central concern in the design of building drainage and vent systems since the 1850s. Failure to provide the necessary protection, primarily through appliance water trap seals, was shown to have been a significant contributor to the Severe Acute Respiratory Syndrome (SARS) epidemic spread in Hong Kong, China, in 2003. Prevention depends upon both good design, to limit the air pressure transients propagated within the system, and good maintenance. Good practice has evolved to include wherever practical long radius bends to minimize the local air pressure changes. Similarly, modern usage of drainage networks includes the random discharge of disposable sanitary and hygiene products that may interact with undesirable rapid changes in flow direction and thereby contribute to local surcharge conditions. However, a maintenance regime within a large complex building network also requires a degree of prior knowledge of possible defective appliance trap seal locations. This paper proposes the use of air pressure transient simulation and transient response measurement to identify, during periods of system non-use, the location of depleted trap seals. The simulation of air pressure transient propagation within building drainage and vent systems is detailed, based on the proven capabilities of the method of characteristics solution of the St Venant equations. Validation of system transient response simulation is presented together with indications of the impact of a defective appliance trap seal on the system response to an applied low-amplitude, short-duration, pressure surge. Comparison of the defect free and defective system response is shown to be sufficiently discriminatory to allow the identification of an appliance trap seal in need of replenishment. Identification of persistent trap seal depletion would allow local installation of active control devices to prevent further failures - including the addition of either air admittance valves to limit trap seal loss to negative transients or variable volume containment positive air pressure attenuators to limit trap seal loss due to positive pressure transients.     

龚嘴大坝坝基渗出物成因分析研究

对龚嘴电站大坝坝基渗出物的特征、类型和成分以及渗出量的动态变化进行了研究，探讨了渗出物质的主要可能来源和成因机制。研究认为，渗出物的主要成分为铁、锰、钙的氧化物，由于其实际的元素渗出量不大，不会对大坝安全造成有意义的不利影响。     

紫色土丘陵区小流域地面侵蚀量预报

 针对长江上游紫色土丘陵区小流域面积侵蚀及泥沙输移特征以及现有资料的可利用性，用演绎法建立了小流域地面侵蚀的预报模型及相应的输沙预报模型。模型参数求取简便，经研究区的典型小流域实测资料检验，预报精度较高，可用于研究区资料短缺小流域的地面侵蚀量和输沙量的估算。     

Water-table variation in a sloping aquifer due to random recharge

Variation in the level of the water table is closely linked with recharge. Therefore, any uncertainty associated with the recharge rate is bound to affect the nature of the water-table fluctuation. In this note, a ditch-drainage problem of a sloping aquifer is considered to investigate the effect of uncertainty in the recharge rate on water-table fluctuation. The rate of recharge is taken as an exponentially decaying function with its decay constant as a Gaussian random variable. Expressions for the first two moments of the water-table height, i.e. mean and standard deviation, are presented. By using these expressions, the effect of uncertainty in the recharge rate on the water-table fluctuation has been analyzed with the help of a numerical example.