一类函数留数计算的两个简化方法

在传统计算留数的常用方法的基础上介绍了两个新的定理,把孤立奇点处的留数计算简化,尤其是对于奇(偶)函数在孤立奇点处的留数更加简化。     

热网工程低真空供热方案的利弊分析

在热电厂的供热机组已确定的条件下,供热方案的优劣就直接影响机组的供热能力、供热面积、热网投资、发电煤耗，影响热电厂的经济效益及热网供热系统的安全性、灵活性和可靠性。本文即是通过对铁煤集团热网工程的三环制供热方案及改造成低真空供热方案的比较分析,对热网工程中低真空供热的利弊进行了初步探讨。     

Distribution characteristics of minerals and elements in chromite ore processing residue

In this paper,environmental scanning electron microscopy (ESEM) is applied to characterizing the mineral and element distribution of chromite ore processing residue (COPR).The test results show that Cr-bearing brownmillerite occurs in the rim of COPR particle,while hydroandradite with Cr(Ⅵ) in its structure presents inside the COPR particle.Periclase and calcite occur in the interstitial area.Element analyses show that Ca,Fe and Al are distributed throughout the COPR particle,and Mg exists mostly in the interstitial area or on the particle surface.A lower content of Cr is evenly distributed in the COPR particle,while slightly higher concentration of Cr occurs inside the particle.It is suggested that it will take a relatively longer time for Cr to migrate out of COPR,especially for hexavalent chromium,so the leaching time and the particle size may be two important factors to affect the release of Cr(Ⅵ).     

阳逻码头堆场软基真空预压处理的应用与效果分析

结合具体工程实例,对软基真空预压施工进行了阐述,提出了质量保证措施,并对施工监测数据进行分析,以完善施工工艺,从而提高真空预压处理水平,可为同类工程提供参考借鉴。     

剩余类环上矩阵的可逆性

类似于数域上矩阵的可逆性的讨论,研究了模m剩余类环上矩阵的初等变换、方阵的行列式、矩阵的秩和矩阵的可逆性,得到了关于剩余类环上的矩阵的几个特殊的结论.     

Determination of organophosphorus pesticide residues in vegetables by an enzyme inhibition method using α-naphthyl acetate esterase extracted from wheat flour

The widespread use of organophosphorus pesticides (OPs) poses a great threat to human health and has made the detection of OP residues in food an important task, especially in view of the fact that easy and rapid detection methods are needed. Because OPs have inhibitory effects on the activity of α-naphthyl acetate esterase (ANAE) in plants, in this work we evaluated the possibility of detecting OPs in vegetables with ANAE extracted from commercial flour. The limits of detection (LODs) obtained for methamidophos, dichlorvos, phoxim, dimethoate, and malathion in lettuce samples with crude ANAE were 0.17, 0.11, 0.11, 0.96, and 1.70 mg/kg, respectively. Based on the maximum residue limits (MRLs) for OPs in food stipulated by Chinese laws which are 0.05, 0.20, 0.05, 1.00, and 8.00 mg/kg for methamidophos, dichlorvos, phoxim, dimethoate, and malathion, respectively, the esterase inhibition method with crude ANAE had sufficient sensitivity to detect the residues of dichlorvos, dimethoate, and malathion in lettuce, but it could not be used to guarantee the safety of the same samples if methamidophos or phoxim residue was present. The sensitivity of the method was improved by the use of esterase purified by ammonium sulfate salting-out. The LODs obtained for methamidophos and phoxim with purified esterase were lower than the MRLs for these OPs in food. This is a very promising method for the detection of OP residues in vegetables using crude or purified esterase because of its cheapness, sensitivity, and convenience.     

Development of an electrochemical immunoassay for detection of gatifloxacin in swine urine

To detect gatifloxacin (GAT) residue in swine urine, an electrochemical immunoassay was established. An indirect competitive immunoassay was developed, in which the coating antigen is immobilized in an enzyme-linked immunosorbent assay (ELISA) plate and GAT residue from the sample competes with the limited binding sites in added anti-GAT antibody. Horseradish peroxidase (HRP) conjugated to goat anti-rabbit IgG was used as the enzymatic label. A carbon fiber working electrode was constructed and current signals were detected by using hydrogen peroxide as a substrate and hydroquinone as an electrochemical mediator. The electrochemical immunoassay was evaluated by analysis of GAT in buffer or swine urine and an average value of half inhibition concentration (IC₅₀) of 8.9 ng/ml was obtained. Excellent specificity of the antibody was achieved with little cross-reaction with lomefloxacin (3.0%), ciprofloxacin (3.0%), and ofloxacin (1.9%) among commonly used (fluoro)quinolones. In conclusion, the immunoassay system developed in this research can be used as a rapid, powerful and on-site analytical tool to detect GAT residue in foods and food products.     

真空堆载联合预压在浙江舟山武港码头工程的应用

采用真空联合堆载预压技术能通过排水固结提高地基承载力,和其他处理方法相比,能降低工程造价。结合工程实例,对加固原理、施工工艺、施工质量控制要点进行阐述,并通过监测和检测结果分析,为同类工程提供参考借鉴。     

真空导入模塑技术在风力发电产业的应用调查与分析

文章简要介绍了十一五期间快速崛起的风电行业,以及风电用复合材料VARTM工艺的背景和基本原理,这项技术的应用情况、材料介绍、工艺过程和发展方向等内容,总结这一技术的现状、问题和未来的发展趋势,以期对于风电行业有点滴的参考和借鉴意义。     

低品位热能与潮汐能驱动的多效蒸馏海水淡化装置

提出了一种利用低品位热能和潮汐能驱动的多效蒸馏海水淡化技术,其特点是利用潮汐能代替传统电泵为系统运行提供动力,从而减少了系统运行对稳定电力供应的依赖,降低造水成本.根据该技术的原理,设计搭建了一套试验系统,测试并分析了给海水温度和加热水温度对该系统运行性能的影响.试验结果表明,当加热水温度为65℃,系统绝对压力为25kPa时,系统的淡水产量为27kg/h.通过试验和理论分析发现,选择合适的加热水温度是维持系统稳定运行的关键因素.