机械零部件表面硬度无损检测的研究

针对传统硬度测量方法的局限性,阐述了超声波、电涡流等无损检测手段进行机械零部件表面硬度测量的系统和原理,并对无损硬度检测方法的应用进行了简单介绍,最后得出无损检测表面硬度是优势。     

液化石油气钢瓶容积测定的重要性

文章认为,液化石油气已经成为人们日常生活中的重要燃料之一,液化石油气钢瓶的安全质量控制越来越受到重视。     

动力工程

一种值得关注的城市天然气消费方式：双源可逆型供暖（空调）系统，球形不锈钢电离室响应实验研究,湿蒸汽两相压缩过程工作特性理论研究，天然气-氢气-空气混合气的层流燃烧速度测定,基于分布式供能技术的能源系统.[编者按]     

信息化指数模型及上海信息化水平的测定

The paper gives an improved model of informatization index. With this model, the social informatization indices of Shanghai from 1995 to 1999 are measured. The social informatization level of Shanghai in those 5 years is analyzed.     

测定等高点巧绘地形图

大比例尺地形图是建筑工程规划、设计、施工和竣工管理等不可缺少的重要资料,本文详细阐述了大比例尺地形图测绘的一种新方法——测定等高点,巧绘地形图。     

用图象法分析“测定电源电动势和内阻”实验中的E、r误差

高中物理电学实验“测定电源电动势和内阻”中为了减小实验误差,我们采用图象法描绘出U-Ⅰ图线,通过求图线的截距和斜率,根据外电压和电流的关系式：U=E-rⅠ,从而得到电源的电动势E和内阻r,但是由于电流表和电压表内阻会引起实验误差,具体分析如下。     

A rapid and accurate 3-（4,5-dimethyl thiazol-2-yl）-2,5-diphenyl tetrazolium bromide colorimetric assay for quantification of bacteriocins with nisin as an example

The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125～32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7～8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24～28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.