浅析地表水资源的保护与管理

本文针对地表水资源污染与保护的现状,就如何建立一个用科学的发展观指导的地表水资源管理保护体系,合理使用水资源,满足未来经济、社会发展及环境维护的需要问题进行了分析和探讨。     

上海市安全饮用水保障技术

介绍上海市供水及供水技术概况,就目前原水水质、出厂水水质及管网水水质现状与存在的问题,提出了改善上海市供水水质的技术措施。构建上海市安全饮用水保障体系的对策:中心城区通过改善原水水质,强化给水厂常规处理,全面实施给水厂深度处理,更新和改造城市供水管网,改造二次供水设施,实施从源头到龙头的供水管理新机制;郊区推行供水集约化建设,建设城乡一体化的供水系统;同时完善城市供水监控体系。     

万家寨引黄工程联接段预应力钢筒混凝土管道安装

文中介绍了预应力钢筒混凝土管道的装卸、运输、堆放和辅设安装的施工工艺。     

三峡二期上游围堰防渗工程若干问题的研究

二期上游围堰施工直接关系到三峡工程的总工期，工程量大，工期紧、施工强度高、防渗基础复杂是影响三峡工程施工成败的关键性项目之一。二期上游围堰在设计洪水时，库内蓄洪容积达２０亿ｍ＾３，万一失事，将造成工程及下游生命财产的重大损失，其重要性物技术复杂不是一般围堰工程所能比拟的，许多专家都指出：“二期围堰关键在防渗工程”。     

人性化家具的情感尺度

随着对家具设计研究的深入,人性化、情感化的家具正一步步的回归到家具设计的主题,也就是说情感化正成为设计师的追求之一。人们在使用家具的同时,也与之进行着不自觉的情感交流,从而获得喜怒哀乐等不同的感受。从人对家具的真实感受出发进行设计实践,才是真正的"以人为本"的人性化设计思想。     

Reverse Microemulsion Synthesis and Characterization of Pd-Ag Bimetallic Alloy Catalysts Supported on Al2O3 for Acetylene Hydrogenation

Pd-Ag bimetallic alloy nanoparticles were synthesized by the reverse microemulsion method,and then deposited on Al2O3 to form the supported catalyst.The nanoparticles of Pd-Ag and Pd-Ag/Al2O3 samples were characterized by UV/Vis,HRTEM,EDX,XRD,and XPS.The test results indicated that Pd-Ag bimetallic alloy nanoparticles with a size of about 2 nm and a face-centered cubic(fcc) structure were formed in the measured area of microemulsion.The growth of nanoparticles was effectively limited within the droplet of micoremulsion.TEM image exhibited that the Pd-Ag alloy nanoparticles were well-dispersed on the Al2O3 support.The catalytic performance of various catalysts for selective hydrogenation of acetylene showed that a higher acetylene conversion and selectivity to ethylene upon acetylene hydrogenation was achieved on a nano-sized Pd-Ag bimetallic catalyst with a Pd/Ag alloy supported molar ratio of 1:1.5.     

大型医疗设备电气设计要点

本文详细介绍了磁共振设备（MRI）、加速器、X射线设备等医院建筑中常用的大型医疗设备的工作原理、临床应用、负荷特性和主要电气参数，并对相应设备的供电方案、配电系统、照明和接地等主要电气设计要点加以说明，可为电气设计人员提供参考。     

Sidelobe suppression in NC-OFDM systems using constellation adjustment

In this letter, a new method for sidelobe suppression in non-contiguous orthogonal frequency division multiplexing (NC-OFDM) systems is proposed. Unlike the conventional approach, sidelobes are suppressed by iteratively adjusting the constellation points for the subcarriers that are close to the edges of the used bandwidth. The constellation points corresponding to the maximum sidelobe suppression are chosen for transmission. Simulation results show that the proposed algorithm yields good performance improvement in terms of sidelobe suppression, and does not have a significant impact on the peak-to-average power ratio (PAPR).     

Identification of the gene PaEMT1 for biosynthesis of mannosylerythritol lipids in the basidiomycetous yeast Pseudozyma antarctica

The yeast Pseudozyma antarctica produces a large amount of glycolipid biosurfactants known as mannosylerythritol lipids (MELs), which show not only excellent surface‐active properties but also versatile biochemical actions. To investigate the biosynthesis of MELs in the yeast, we recently reported expressed sequence tag (EST) analysis and estimated genes expressing under MEL production conditions. Among the genes, a contiguous sequence of 938 bp, PA_004, showed high sequence identity to the gene emt1, encoding an erythritol/mannose transferase of Ustilago maydis, which is essential for MEL biosynthesis. The predicted translation product of the extended PA_004 containing the two introns and a stop codon was aligned with Emt1 of U. maydis. The predicted amino acid sequence shared high identity (72%) with Emt1 of U. maydis, although the amino‐terminal was incomplete. To identify the gene as PaEMT1 encoding an erythritol/mannose transferase of P. antarctica, the gene‐disrupted strain was developed by the method for targeted gene disruption, using hygromycin B resistance as the selection marker. The obtained ΔPaEMT1 strain failed to produce MELs, while its growth was the same as that of the parental strain. The additional mannosylerythritol into culture allowed ΔPaEMT1 strain to form MELs regardless of the carbon source supplied, indicating a defect of the erythritol/mannose transferase activity. Furthermore, we found that MEL formation is associated with the morphology and low‐temperature tolerance of the yeast. Copyright © 2010 John Wiley & Sons, Ltd.     

地下工程抗浮加固设计

地下工程的抗浮设计非常重要,往往决定着工程的成败。本文所述案例由于原设计未充分考虑地下水的影响而致使事故的发生。笔者通过对事故现象的分析,找出了造成事故原因,从而采取经济合理的加固方案使该工程达到了较为满意的经济和社会效益。