施工企业经评审的最低投标价法

随着建筑市场竞争的日益激烈,经评审的最低投标价法的推行,施工企业盈利空间变小。本文基于推行经评审的最低投标价法对施工企业的影响,对施工企业如何应对进行了相关分析,并提出相应对策。     

低成本分布式邮件备份系统的设计和实现

为了利用廉价的普通桌面电脑构建高性能、高可靠、低成本的电子邮件备份系统,设计了基于SOA的对等网络存储架构,贯彻了低耦合、无状态、异步通信和自适应的设计原则。系统将输入数据流和输出数据流分开处理,分别将邮件数据和索引信息保存在磁盘文件和数据库中,兼顾了高容量和快速查找的的要求。     

Ecofriendly synthesis of MWCNTs by electric arc in aqueous medium: Comparative study of 6B pencil and mineral graphite

The production of carbon nanotubes (CNTs) by electric arc discharge (EA) usually applies pure mineral graphite (PMG) as the precursor electrode due to its high-purity and conductivity. This work investigated the versatility of EA in aqueous medium for the production of CNTs by varying the electrodes purity degree. In this way, a variety of domestic and industrial graphite waste can be recycled into high-quality CNTs by adjusting the EA parameters. CNTs were synthesized using 6B pencil (6BP, ~57% graphite) and their quality and quantity were compared to the PMG (99.995%) production. PMG led to short CNTs (I_D/I_G 0.266), while the synthesis with 6BP led to long CNTs (I_D/I_G 0.428). The 6BP CNTs showed elevated quality for application in the electronic, biomedical, and optical fields.     

Natural refining of extruded-expelled soybean oils having various fatty acid compositions

Simple, low-capital-investment oil refining techniques, which may also meet the needs of natural or organic food industries, were explored to process extruded-expelled (E-E) soybean oils with various fatty acid compositions. Most settled E-E oils are naturally low in phosphatides (<100 ppm phosphorus) and were easily water degummed to low phosphorus levels (<55 ppm). Free fatty acids were reduced to 0.04% by adsorption with 3% Magnesol^®. Magnesol reduced residual phosphorus contents to negligible levels. This material also adsorbed primary and secondary oil oxidation products. Our adsorption refining procedure was much milder than conventional refining, as indicated by little formation of primary and secondary lipid oxidation products and less loss of tocopherol. The remaining challenge to effective natural refining is the removal of off-flavor components. Our adsorption treatment reduced the natural flavor of soybean oil but flavor was still present, probably too strong for many consumers. Polyunsaturated oils oxidized more easily than did the other types of oils; therefore, precautions should be taken when refining such oils. High-oleic soybean oil, on the other hand, had excellent oxidative stability and better flavor characteristics after degumming and adsorption with Magnesol compared with other oils.     

Power Plants

The famed ecodesigner Ken Yeang files the first of his stories for a new series for AD+. Here he hails the introduction of an exciting new technology - a photovoltaic system - that imitates photosynthesis in nature. Copyright © 2007 John Wiley & Sons, Ltd.     

廉价摆槽式定尺飞剪--低成本自动化的实现

本文介绍一种低成本的摆槽式定尺飞剪,并与其他形式飞剪进行了性能价格比较.利用老式摆槽式飞剪的机械设备,加上相应的传感元件和数字控制系统,也可获得与其他造价昂贵的飞剪近似的高精度.     

低成本选择性激光烧结快速成形设备的设计和研制

在保证ＳＬＳ设备性能的前提下,针对ＳＬＳ设备的特点,以综合成本最低为目标,研制成功了低成本ＳＬＳ快速成形设备。讨论了低成本ＳＬＳ快速成形设备的设计和研制思想,介绍其设计和研制中的一些关键技术。提出的一新思想、新技术和新方法,对大幅度降低ＳＬＳ快速成形设备的成本具有重要意义。     

退台方院及其架空层的起伏——网龙公司长乐园区职工宿舍所引发的思考

退台方院这一设计概念已经成为了网龙公司长乐园区新职工宿舍的代名词,但除此之外,架空层起坡的硬质石材地面让这个项目与OPEN建筑事务所以往的作品显得不同。如何解释这些在低造价限制下完成的特定的形式语言(变体),以及这些具体的语言与使用人群的关联是本文所关注的。     

安钢帘线钢LX70A的研制开发

介绍了安钢帘线钢LX70A的研制开发过程,其生产工艺流程为：100 t转炉—100 t LF—R8×150 mm×150 mm方坯连铸机—高速线材轧机控制轧制。通过采用高拉碳、优化精炼和连铸工艺等技术措施,以较少的工序、较低的成本成功开发出帘线用钢LX70A,取得了良好的使用效果。     

Criteria for the economic planning of a low power hydroelectric plant

This paper presents an original method for finding the most economically advantageous choice for the installation of micro hydroelectric plants.More precisely, the paper that follows is to be considered in a context defined as “problematic” by those who have the job of constructing water-flow plants with only small head and modest flow rates. With these initial data one can see immediately that the specific energy of the fluid is low and it is therefore necessary to elaborate large masses of water in order to obtain work, and therefore a return, to render such an investment profitable. Traditional plant solutions using Kaplan or Francis type turbines must be rejected because of the high levels of initial investments. Much more simple configurations must be analysed, such as plants with propeller turbines or Michell–Banki turbines, in order to reduce the investment costs.The general methodology applied provides a powerful decision-making instrument which is able to define the best plant configuration. The method is based on the use of economic profitability indicators, such as the Net Present Value (NPV), calculated using the plant project parameters, the nominal flow rate and head, and the particular hydrologic characteristics of the site, such as the type of distribution, the average value and the standard deviation of the flow rates in the course of water supplying the plant.A numerical example for a plant situated in the Emilian Appennine Range then makes it possible to demonstrate the simplicity and applicability of the proposed method.