单相电源供电的平滑加电灯丝电路

本文介绍一种单相电源供电的平滑加电灯丝电路。使用这种电路可延长发射机大功率电子管的寿命。     

热固性聚合物中裂缝的扩展

简介热固性聚合物广泛地用作纤维增强复合材料的基体。这些基体一般都较脆,所以对其断裂性能引起极大的关注。用线弹断裂机理(LEFM)研究热固性聚合物中裂缝扩展方面的最新进展已有评述。文中表明,近来在了解控制裂缝扩展的判断方面取得了很大进展。对连续性扩展和粘滑性扩展来说,断裂的判断都是:在裂缝的临界距离前方材料所受的临界应力必须达到屈服应力的3至4倍。本文也讨论了产生裂纹的可能性,以及微观结构对裂缝扩展的影响,     

大长今养生御膳精选（一）

炖鲍鱼 原料：鲍鱼（中）8个，牛肉（里脊）100g，干香菇8朵，高汤1杯，银杏（白果）10粒，松子，薄盐酱油少许。     

影响我厂造气废热锅炉寿命的原因及采取的措施

介绍了该厂造气废热锅炉损坏情况、原因分析及改进措施。     

How commercial involvement affects open source projects: three case studies on issue reporting

Whereas most research on Internetware has focused on new technologies for keeping track of a changing Internet,little attention has been paid to the software development process.A large portion of the software running the Internet is open source software.Open source software is developed both by volunteers and commercial companies,often jointly.Companies get involved in open source projects for commercial reasons,and bring with them a commercial software development process.Thus,it is important to understand how commercial involvement affects the software development process of open source projects.This article presents case studies of three open source application servers that are being developed jointly by a volunteer community and one primary software company.We are interested in better understanding developer behavior,specifically task distribution and performance,based on whether the developer is an external contributor,e.g.,a volunteer working in their spare time,or a commercial developer from inside the primary backing company who is being paid for their time.To achieve this,we look at issue reporting as an example of commercial involvement in open source projects.In particular,we investigate the distribution of tasks among volunteers and commercial developers by studying the source of reported issues and quantify the task performance on user experience via the issue resolution speed.We construct measures based on historical records in issue tracking repositories.Our results show that,with intensified commercial involvement,the majority of issue reporting tasks would be undertaken by commercial developers,and issue resolution time would be reduced,implying a better user experience.We hope our methods and results provide practical insights for designing an efficient hybrid development process in the Internetware environment.     

不锈钢的表面加工——制造方法与用途（13）——Ⅲ根据用途要求的材料表面

（一）前言 不锈钢具有优良的耐久性、强度和加工性等，在汽车、家电、厨房机械和建材等部门被广泛使用。随着其用途的扩大，还对不锈钢表面进行了涂层和电镀的表面处理，开发了具有观赏性、功能性的表面处理不锈钢。其中，在家电用途中，具有优良观赏性的透明涂层不锈钢和具有优良加工性的固态润滑涂层不锈钢已经开始使用。本文特对近年来在家电部门扩大使用的透明涂层不锈钢和润滑涂层不锈钢进行介绍。     

北方机场水泥混凝土道面常见病害及预防措施

北方机场水泥混凝土道面常见病害有道板错台、道面裂缝、边角脱落和板体断裂四类病害,这些病害不仅与混凝土的使用性能有关,还与北方地区复杂的气候条件有关。相较于道面产生病害以后再进行处理,病害预防工作在维护机场安全方面更为重要。科学制定和严格执行预防措施,可以有效预防我国北方地区机场混凝土道面病害的产生,最大限度地提高道面的使用寿命,从而保障机场的安全运营。     

新型杂化有机硅技术及其应用

在改进纺织品功能和节约工艺成本的同时,提高纺织品应用安全性一直是新型纺织助剂的发展目标。具有革命意义的杂化有机硅最新一代产品以其独特的方式兼备上述标准。将3个正在申请专利的新型杂化有机硅改性剂用于进行具有最佳柔软性的氟碳整理和牢度改进的超亲水柔软剂领域,以展示此新一代有机硅柔软剂的优点。     

Inertial Waves Occurring in a Liquid Metal Column due to Pulsed Excitation by a Rotating Magnetic Field

We present an experimental study concerning the flow inside a liquid metal column exposed to a pulsed rotating magnetic field.This paper is aimed at highly resolved,quantitative velocity measurements in the eutectic GalnSn alloy.A novel ultrasound Doppler system was used two measure two-dimensional velocity fields of the secondary flow in the radial-meridional plane.It employs an array of 25 transducer elements allowing a fast electronic traversing with concurrently high spatial and temporal resolution.The measurements revealed transient flow regimes showing distinct inertial oscillations and coherent vortex structures.The results demonstrate that the arising flow structure depends sensitively on the frequency of the RMF pulses.A maximum intensity of a periodic meridional flow can be observed,if the corresponding pulse frequency fp relates to the eigenperiod of the respective inertial mode in a developed regime.The electromagnetic stirring method that uses a modulated RMF offers considerable potential to enhance the stirring efficiency and to optimize the properties of castings by a well-aimed flow control during solidification.