溶胶—凝胶法制备有机改性硅酸盐的研究进展

综述了有机改性硅酸盐的溶胶－凝胶合成路线，并简要介绍它们的结构、性能及应用     

若干无机盐对聚丙烯酰胺溶液粘度的影响

探讨了无机盐溶液中阴阳离子对聚丙烯酰胺(PAM)溶液粘度的影响,确定了影响PAM溶液粘度的主要因素是二价阳离子(如ca2 及Mg2 离子)。     

高温水采暖系统内部氧腐蚀

对阜康冶炼厂高温水采暖系统内部产生氧腐蚀的原因进行分析，采取相应的措施，收到良好的效果     

城市防洪泵站振动测试技术探析

为对城市防洪泵站运行中异常、连续的振动进行测试,为泵站维修前后的振动提供对比数据,安装振动测试系统。分析泵站振动变送器的原理、选型,介绍测试系统的组成原理,阐述振动测试系统的安装及注意事项,以及测试系统的校准方法。振动测试系统投入运行几个月来采集的数据,对振动工况的判断、水泵和电机的运行性能,以及维修前后的振动情况对比提供支持,达到了预期目的。     

Theoretical analysis of the harmonic characteristics of modular multilevel converters

To understand the operation principle of the modular multilevel converter(MMC)deeply,it is necessary to study the harmonic characteristics of the MMC theoretically.Besides,the analytical harmonic formulas of the MMC are useful in designing the main circuit,reducing the losses and improving the waveform quality.Based on the average switching function and the Fourier series harmonic analysis,this paper deduces the analytical expressions for such electrical quantities as the arm voltage,the arm current,the capacitor voltage,the capacitor current and the circulating current of the MMC.Finally,a digital model of a 21-level MMC-HVDC system is realized in PSCAD/EMTDC.The results of the analytical expressions coincide with the simulation results,which verify the effectiveness and feasibility of the proposed analytical expressions.     

真空环境下的二元冰制备特性研究

采用理论分析与试验相结合的方法,对真空环境下的二元冰生成动态特性进行研究。分析了闪蒸室内压力、水套温度、供水温度、速率、不同水质等各因素对二元冰晶生成的影响。研究结果表明:闪蒸室压力、供水水温、水质以及水滴初始直径、速率都对二元冰真空制备具有较大的影响,其中,闪蒸室压力升高,水滴闪蒸、结冰速率明显下降;供水温度越低,水滴达到同一状态所需的时间越短;水滴初始粒径的增加,水滴闪蒸、结冰的进程明显变慢。闪蒸室温度对水滴的闪蒸、结晶影响不是很大。     

Optimising Reliability: Portfolio Modeling of Contract Types for Retail Water Providers

This paper considers the retail water provider’s purchasing decision of a portfolio of permanent contracts from wholesalers with multiple volatile water sources. We consider the reliability of two contract types: (1) fixed annual quantities, and (2) an inflow harvest function with storage. Our four-reservoir case in Sydney (Australia) has cross-correlated inflow data. To accommodate multi-reservoir cross-correlation we adapt Portfolio Theory from finance to lognormal reservoir inflows, re-framing traditional storage theory from the wholesaler’s optimal operating policy to the retailer’s optimal purchasing policy. We find that Reliability improves with access to a source pool (cf. fixed quantities from separate sources), demonstrating the ‘insurance effect’, and the portfolio that minimises lognormal variance also minimises harvest (and thus environmental impact). Reform direction in Australian (and other international) water markets is towards multi-provider vertical disintegration, which may reduce pool opportunities and negate the insurance effect. We consider diminishing reliability returns as reservoir harvesting increases, and conclude a retail portfolio of permanent contracts from reservoirs, plus short-term contracts from alternative sources (either independently or negatively cross-correlated) efficiently secures high reliability. The challenge in incomplete water markets remains in encouraging and sustaining supply diversification that may only be needed aperiodically during extreme droughts.     

论灌区水文生态禀赋及建设生态文明

运用新的水文生态的观点分析了灌区问题,将灌区水文系统、生态系统分为渠首引水系统、配水渠系、田间灌溉系统、井渠系统、排水系统、作物系统、土壤及水文地质系统等10个子系统。经过分析论证,灌区是一个典型的水文生态系统,从而揭示了灌区生态文明的实质和内涵,使生态文明灌区建设更具明确的目的和工作内容,为灌区的可持续发展提供了理论依据,也为其他水利工程的水文生态分析提供了参考。     

Observation of the induced pressure in a hybrid mlcro/nano-channel

This paper studies the flow characteristics in micro/nano-channels subjected to an applied electric field. The nano-channel flow was observed by means of the fluorescence Calcein. A Fluorescence Concentration Gradient Interface (FCGI) was observed across the nano-channel array. The front of the FCGI was shown to have an analogous parabolic shape. The propagation of this interface reflects indirectly the induced pressure at the micro/nano-channel junction, where the enrichment-depletion processes are known to take place. This induced pressure was predicted by numerical simulations, and this paper gives the first experimental evidence.     

历史维度下的河西走廊水利问题研究

社会建设和生态文明建设中,历史维度是不可或缺的一环,流域管理亦然。通过对河西走廊近代水资源开发利用历史的回顾,分析了甘肃省河西走廊地区石羊河、疏勒河及讨赖河流域的水资源开发利用、社会经济发展和流域管理的演变,重点探讨了河西走廊地区历史上形成的"以时分水"的时间水权制度的运行情况、人类活动影响下流域水循环特征变化导致时间水权制度失效的机理,以及讨赖河流域传统分水模式与现代水利制度衔接的现实需求与可能方式。研究认为,在历史维度下进行流域管理问题研究,对于深入认识河西走廊水环境演化规律、深刻理解水资源开发利用管理问题的现实内涵、科学制定传统水资源管理与现实发展要求衔接的可行方案具有重要意义。