APP软件性能效率研究

性能效率是APP软件的重要质量属性，但目前缺乏APP软件性能效率的通用模型。分析了APP软件的性能特征，基于ISO/IEC 25010标准提出了APP软件的性能效率模型，定义了APP软件性能效率的子特性和度量指标。基于提出的APP软件性能效率模型，通过实验对APP软件的性能效率进行了度量及相关分析。     

Hydrogen quality sampling at the hydrogen refuelling station – lessons learnt on sampling at the production and at the nozzle

Fuel cell electric vehicles and hydrogen refuelling infrastructure are developing quickly in Europe, the USA and Asia. Hydrogen quality for transport applications requires compliance with ISO 14687-2: 2012 and EN 17124:2018 - this needs representative sampling, at the hydrogen production process and at hydrogen dispenser nozzle (which typically fill vehicles to a Nominal Working Pressure of either 35 or 70 MPa). The low thresholds in ISO 14687-2 for oxygen and water can be exceeded if the sampling procedure fails to purge the system sufficiently, which would lead to false results (60% in this study). Purging requirements to remove water were studied using a low pressure sampling rig. For hydrogen dispenser sampling using the Linde H2 Qualitizer (suitable for dispensing pressures up to 70 MPa), purging number and the effect of the initial fill level of a vehicle compressed hydrogen storage system were investigated experimentally to avoid hydrogen quality violation due to oxygen false positive. The study procedure reduces from 60% to 0% hydrogen quality violation. The next challenges highlighted are safe purging and reliable sampling of reactive contaminants in gas cylinders.     

水泥颗粒分布对水泥和混凝土性能的影响

实施水泥新国家标准后 ,水泥强度明显下降。本文对水泥颗粒分布进行了试验研究 ,分析了对水泥强度、混凝土的工作性能及强度等性能的影响     

Client satisfaction and quality management systems in contractor organizations

The construction industry is predominantly project based and quality is one of the client's prime concerns in their construction projects. Many clients, especially those in the Hong Kong public sector, require their contractors to have a Quality Management System (QMS) certified under ISO9000. Also, several contractors as well as clients themselves voluntarily implemented an ISO9000-based QMS in their respective organizations in order to target the various benefits perceived from such initiative. It was considered timely and worthwhile to explore the effectiveness of ISO9000-based QMSs in the Hong Kong. This paper portrays the key findings from a focused study that relate to the client satisfaction aspects from implementation of the ISO9000-based QMSs in the contractor organizations.     

关于建筑企业全面质量管理的探讨

随着各国质量专家学者掀起了TQM与ISO9000两者关系的研究热潮．文章提出：按国际惯例严格实施ISO9000标准并敢得认证很有必要．但要确保企业持续健康发展．最根本、最有效的途径还是不断深化TQM。     

高等教育管理引进ISO9000族标准的研究综述

我国高等教育管理引进ISO9000族标准的研究从以前的实践研究和国外经验的介绍开始,到现在已经转入理论研究为主,并主要集中研究引进的可行性与必要性、基本术语界定、标准体系的构建.虽然研究已经比较深入,但是依然存在尚待进一步深入研究的问题,如引进领域的确定,对实践的总结与反思等.     

Comparison of a novel MPN method against the yeast extract agar (YEA) pour plate method for the enumeration of heterotrophic bacteria from drinking water

This study compared the Quanti-Disc most probable number (MPN) test for heterotrophic bacteria from drinking water with the widely used yeast extract agar (YEA) pour plate method. The Quanti-Disc test module contains 50 reaction wells in which a medium has been pre-deposited. The medium contains a suite of three fluorogenic enzyme substrates selected for the detection of enzymes expressed widely by heterotrophic bacteria. The MPN of heterotrophic bacteria is calculated from the number of fluorescing reaction wells after incubation of a sample. Quanti-Disc and the YEA pour plate method were compared according to guidance on comparing methods given in United Kingdom national guidance and ISO 17994:2004. The two methods were also challenged with reference strains and isolates of heterotrophic bacteria from drinking water. This indicated that heterotrophic bacteria commonly encountered in drinking water are detected by both the YEA pour plate method and Quanti-Disc. Analysis of data from split water samples (723 for 37 degrees C tests and 872 for 22 degrees C tests) from nine geographically diverse laboratories in England and Wales demonstrated that the Quanti-Disc method is equivalent to the YEA pour plate method for the analysis of heterotrophic bacteria from drinking and similar waters at 37 degrees C, and superior to YEA for the analysis at 22 degrees C. The Quanti-Disc method is a simple and efficient alternative method for the enumeration of heterotrophic bacteria from drinking water.     

ISO14000标准在供水企业中的实施——以广州开发区供水管理中心为例

本文通过对广州开发区供水管理中心现状的分析,提出了实施ISO14000标准环境管理体系的重点和步骤,最后提出了在供水企业实施ISO14000环境管理体系的一些建议。     

楼梯升降机简介

介绍楼梯升降机的结构、参数、特点、具体应用和选购指南。     

Trace level analysis of reactive ISO 14687 impurities in hydrogen fuel using laser-based spectroscopic detection methods

Hydrogen fuelled vehicles can play a key role in the decarbonisation of transport and reducing emissions. To ensure the durability of fuel cells, a specification has been developed (ISO 14687), setting upper limits to the amount fraction of a series of impurities. Demonstrating conformity with this standard requires demonstrating by measurement that the actual levels of the impurities are below the thresholds. Currently the industry is unable to do so, for measurement standards and sensitive dedicated analytical methods are lacking. In this work, we report on the development of such measurement standards and methods for four reactive components: formaldehyde, formic acid, hydrogen chloride and hydrogen fluoride. The primary measurement standard is based on permeation, and the analytical methods on highly sensitive and selective laser-based spectroscopic techniques. Relative expanded uncertainties at the ISO 14687 threshold level in hydrogen of 4% (formaldehyde), 8% (formic acid), 5% (hydrogen chloride), and 8% (hydrogen fluoride) have been achieved.