Determination of the field of a permanent-magnet disk machine using the concept of magnetic charge

An analytical solution of the dependence of the field distribution on the three-spatial coordinates in a permanent-magnet (PM) disk machine is obtained using the concept of magnetic charge and the method of images. A good correlation between the analytical solution and experimental data validates the method described. It is further indicated how this method can be extended to more complex problems. It is applicable to other PM machines, such as permanent-magnet linear synchronous motors.<>     

Fractionation and characterisation for antioxidant activity of hydrolysed whey protein

Whey protein isolate (WPI) was hydrolysed for 1 h using Alcalase, Protamex and Flavourzyme. Native WPI, hydrolysed WPI and two commercial WPI hydrolysates were subjected to fractionation by size exclusion chromatography. Antioxidant activity of WPI fractions was measured with a liposome‐oxidising system (50 µM FeCl₃/0.1 µM ascorbate, pH 7.0). Lipid oxidation was measured as thiobarbituric acid‐reactive substances (TBARS). Gel electrophoresis and amino acid analysis were run to identify the peptide composition. The influence of amino acid composition on antioxidant activity was evaluated using multivariate analysis methods (correlation analysis, principal component analysis, multiple linear regression and discriminant analysis). TBARS assays indicated the presence of antioxidant activity in all protein fractions, including non‐hydrolysed WPI. For native and hydrolysed WPI samples the first fraction (> 45 kDa) showed a higher TBARS inhibition effect (24–27%) when compared with lower‐molecular‐weight fractions and hydrolysate mixtures. In contrast, for commercial WPI hydrolysates a higher inhibitory effect was found in most of the lower‐molecular‐weight fractions (30–55%). The ability of WPI fractions to delay lipid oxidation was found to be related to the prevalence of histidine and hydrophobic amino acids. Copyright © 2004 Society of Chemical Industry     

Preparation of branched polyacrylonitrile through self‐condensing vinyl copolymerization

Branched polyacrylonitrile (PAN) was prepared through a self‐condensing vinyl copolymerization of acrylonitrile and 2‐(2‐bromopropionyloxy)ethyl acrylate (BPEA). The branched architecture of the product was confirmed by NMR spectra and the average degree of branching (DB ) was estimated. Through a comparison of the intrinsic viscosity of the product with that of its linear analogue, the contraction factor g′ was calculated. It was found that the viscosity of the branched PAN was obviously lower that that of linear PAN. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

一种网络服务自动部署方法

为满足网络服务使用者对网络服务部署的功能性和非功能性需求,运用Petri网的方法进行了互联网动态多变环境下的网络服务自动部署的研究,建立了一种基于Petri网的网络服务部署网模型,从形式化的角度描述了网络服务功能的部署情况,提出了一种按照服务质量来选择最优网络服务部署的算法。仿真的结果表明,与目前常用的固定部署算法和随机部署算法相比,按照该方法得到的网络服务部署能最好地满足服务使用者对服务的非功能性方面的需求。     

论江西省农村饮水安全工程规划

本文通过参与江西省农村饮水安全工程规划的工作的实践经验，重点介绍了江西省农村饮水安全工程规划的一些工作方法和过程，并对其江西省农村饮水安全工程规划进行了总结。     

飞行人员骨密度与内分泌调节关系的探讨

对37名骨密度(BD)低下的飞行员(实验组)和BD正常的48名飞行员、100名地面人员(正常对照组)进行了BD和血清TT_3、TT_4、TSH IRMA、CT、PTH、E_2和T放射免疫测定。结果显示,实验组BD均值明显低于对照组(p<0.01),血清TT_3、TT_4、CT、E_2(女性)和T(男性)均值与对照组比较,大多数年龄存在着显著或非常显著差异(p<0.05或p<0.01)。同时对飞行人员BD与几种内分泌激素关系进行了探讨。     

平均声压级近似计算误差分析

本文用凸集理论分析了平均声压级近似计算的误差,导出了最大误差计算公式,指出了测量数据在何种状态下误差达到最大值。     

机载雷达空时二维信号处理自适应权值训练的距离分段递推算法

本文针对机载预警雷达的杂波环境，分析了杂波数据的非平稳性，由此提出在距离上分段实现空时二维自适应处理（STAP）的方法，并通过分析杂波于空间的距离来确定分段的方法。在同时考虑实时性和处理器性能的前提下，给出了一种自适应权值计算的递推算法。理论分析和计算机仿真结果均表明，本文提出的分段递推算法是有效的。     

注塑件/模具成本评估方法研究综述

对注塑模成本评估领域的主要研究方法进行了分析 ,指出了相关的几个成本评估流派。着重对成本评估的CEF方法进行了总结 ,并对当前国际上流行的派别的优缺点进行了总结。文末 ,给出了我们的研究思路大体概述     

铝合金电火花线切割加工工艺研究

通过对铝合金高速走丝电火花线切割加工的工艺设计，探讨了其加工的工艺特点，分析了不同的进给速度、工作液及电参数对加工工艺指标的影响，并提出了改善铝合金高速走丝线切割加工工艺性能的措施。