硼氢化钠的性能与应用

硼氢化钠是一种重要的离子型化合物,它的用途很广泛。文章论述硼氢化钠的两种重要性质——还原性和水解性,叙述了硼氢化钠的应用并简介了其制备方法。     

Statistics, ethics and probiotica

Ethical issues involved in the design of the ‘PROPATRIA’ probiotica trial are discussed. This randomized clinical trial appeared to be well conducted according to accepted good practices. The finding that the treatment was actually rather harmful, and that despite this, and despite a built‐in interim analysis, the trial was not stopped earlier, led to strong criticism in the media. I argue that ‘accepted good practices’ need to be reconsidered in the light of this experience. First, a much stronger distinction needs to be recognized between the immediate interests of the patients being treated in the trial and the interests of future patients of future doctors elsewhere. Secondly, it is in the interests of future patients that well‐conducted clinical trials are accepted by society. As it is unavoidable that an occasional trial will result in an unpredicted severely negative outcome, ethical screening committees must ensure that those performing a trial can never be accused of putting the interest of ‘science’ above the interest of their own patients when such ‘accidents’ happen. There are two consequences of this. First, the design of a trial should also explicitly lead to minimizing the number of patients who are treated by the researchers with a potentially seriously harmful medicine. Secondly, the disadvantages of triple‐blinding far outweigh the advantages. Although it might at best only have saved a few lives if the PROPATRIA trial been re‐designed with these issues in mind, I argue that the scientific value of the trial would not have been significantly reduced; the damage to medical research, and hence to future patients, would have been substantially less. Closer inspection of the data from the PROPATRIA trial brings a new and quite unexpected failing to light. The decision for stopping the trial early was accidentally based on the one‐sided test looking in the wrong direction, partly through the inadequacy of the output of the statistical package, SPSS and partly through lack of statistical expertise on the part of the users. If the envisaged one‐sided stopping rule had been used correctly, the trial would in fact have been terminated at the time of the interim analysis ‘for futility’; it was at this moment highly unlikely that a significant end‐result in favour of probiotica was going to be attained. The decision to continue the trial was a result of looking at the test statistic ‘in the wrong direction’. In effect, the trial was continued because there was still a good chance to show that probiotica is actually very harmful. I recommend that data‐monitoring committees should always be advised by a professional statistician, who is not blinded to the treatment allocation.     

高频无极灯和低频无极灯的对比应用

文章通过对无极灯发光原理和创新特点的总结,阐述了高频无极灯和低频无极灯的异同,并初步总结出两者之间的对比应用结果。     

GD500-C型抓斗移动式自动清污机在龙溪电厂的应用

抓斗移动式清污机用于水电厂的发电机组进水口,用以清除多组拦污栅拦截的各种杂物。该机器的齿耙能插入栅片中,具有清污彻底、清污量大、操作方便的优点。文章介绍了抓斗移动式清污机在龙溪电厂应用中的改造经验及改造后的运行情况和实际效益。     

环境标准物质在环境监测中的应用

文章介绍了环境标准物质在环境监测中的具体应用,以及使用时的注意问题,同时分析了标准物质的研制方向。     

雨量实时在线监测系统在水情监测中的应用

文章介绍了雨量实时在线监测系统在水情监测中的应用,阐述了雨量实时在线监测系统对于研究降水尤其是暴雨特征具有重要意义,并且对农业、城市建设、电信、交通、水利等国民经济部门及防灾、减灾策略的制定具有重要作用。     

浅谈我国旅游电子商务的发展

随着网络经济的迅速发展,中国旅游业与电子商务结合成为一种必然的趋势。本文主要介绍了我国旅游电子商务的发展现状,分析发展旅游电子商务的优势,同时总结了其应用的主要领域与内容。     

Cloud-based smart asset management for urban flood control

Urban flooding, frequently occurring in metropolitan areas, is one of the largest disasters worldwide. Albeit a large number of approaches and Enterprise Information Systems (EISs) have been designed for urban flood control, the ineffective management of physical assets has greatly impeded their deployment. Managing diverse physical assets is critical in urban flood control. Challenges exist in sharing assets and services between agencies, and ensuring real-time and flexible decision supports. This paper proposes a cloud-based asset management platform. Cloud technology is adopted for processing the huge amount of data collected by various physical assets and for providing flexible access interfaces. Service-oriented methods are applied to facilitate the sharing of assets and services and to enable the development of flexible and scalable Decision Support Systems (DSSs). Moreover, the concept of smart asset is introduced for remote real-time data collection, and the corresponding software agent model is developed to wrap these diverse assets, realising the UPnP (Universal Plug and Play) working mode. Finally, a case study on the urban flood control process of Guangqumen Bridge in Beijing is provided to illustrate the asset management processes of the proposed platform.     

计算机病毒注入方式及临床症状

本文简要探讨了病毒的注入方式及临床症状,旨在提高用户对病毒的诊断能力和防范能力。     

Detecting volatility persistence in GARCH models in the presence of the leverage effect

Most asset prices are subject to significant volatility. The arrival of new information is viewed as the main source of volatility. As new information is continually released, financial asset prices exhibit volatility persistence, which affects financial risk analysis and risk management strategies. This paper proposes a nonlinear regime-switching threshold generalized autoregressive conditional heteroskedasticity model which can be used to analyse financial data. The empirical results based on quasi-maximum likelihood estimation presented in this paper suggest that the proposed model is capable of extracting information about the sources of volatility persistence in the presence of the leverage effect.