基于DSP控制的多输出并网逆变器

针对世界各国电网电压规格种类较多的情况,提出一种基于DSP控制的可输出多个国家电网电压规格的并网逆变器。通过DSP控制和2台逆变器的串联和并联,实现了多种规格电网电压的输出,且串联和并联2种运行模式不影响系统的稳定性。详细阐述了逆变器的工作原理,分析了2台逆变器在串联模式下的均压和在并联模式下的均流效果,及串联和并联2种运行模式对系统稳定性及相对稳定性的影响,并以一台1 000 VA基于DSP控制的串并联双降压式半桥逆变器进行了实验验证。实验结果表明在串联和并联2种运行模式下2台逆变器具有很好的功率均分度。     

Mining Design Pattern Use Scenarios and Related Design Pattern Pairs: A Case Study on Online Posts

In common design pattern collections, e.g., design pattern books, design patterns are documented with templates that consist of multiple attributes, such as intent, structure, and sample code. To adapt to modern developers, the depictions of design patterns, especially some specific attributes, should advance with the current programming technologies, for example, “known uses”, which exemplifies the use scenarios of design patterns in practice, and “related patterns”, which describes the relatedness between a design pattern and the others within a context. However, it is not easy to update the contents of these attributes manually due to the diversity of the programming technologies. To address this problem, in this work, we conducted a case study to mine design pattern use scenarios and related design pattern pairs from Stack Overflow posts to enrich the two attributes. We first extracted the question posts relevant to each design pattern by identifying the design pattern tags. Then, the topics of the posts were discovered by applying topic modeling techniques. Finally, by analyzing the topics specified for each design pattern, we detected 195 design pattern use scenarios and 70 related design pattern pairs, involving 61 design patterns totally. These findings are associated with a variety of popular software frameworks and programming techniques. They could complement the existing design pattern collections and help developers better acknowledge the usage and relatedness of design patterns in today’s programming practice.

     

高温熔体晶体生长的三维实时观察实验装置

最近开发了三维光学实时观察法,应用透视魔镜法实时观察并记录透明晶体的生长和溶解过程,最高使用温度为1000℃配合三维观察,设计并制造了一套独特的生长炉和坩埚,有二组互相垂直的光路可同时实时观察晶体生长过程,并通过CCD摄像头进行同步记录.应用这组设备,观察并记录了KCl枝蔓晶的生长过程．     

An Empirical Comparison Between Tutorials and Crowd Documentation of Application Programming Interface

API (application programming interface) documentation is critical for developers to learn APIs. However, it is unclear whether API documentation indeed improves the API learnability for developers. In this paper, we focus on two types of API documentation, i.e., official API tutorials and API crowd documentation. First, we analyze API coverage and check API consistencies in API documentation based on the API traceability. Then, we conduct a survey and extract several characteristics to analyze which API documentation can help developers learn APIs. Our findings show that: 1) API crowd documentation can be regarded as a supplement to the official API tutorials to some extent;2) the concerns for frequently-used APIs between different types of API documentation show a huge mismatch, which may prevent developers from deeply understanding the usages of APIs through only one type of API documentation;3) official API tutorials can help developers seek API information on a long page and API crowd documentation could provide long codes for a particular programming task. These findings may help developers select the suitable API documentation and find the useful information they need.     

商品化钢筋生产配送信息管理系统的研究与规划

目的：研究商品化钢筋配送信息管理系统中的系统功能规划。方法：针对商品化钢筋生产和配送的业务流程,结合目前的信息技术、物流理论和地理信息系统的运用,考虑了从库存管理、客户订单管理、原材采购、生产数据管理、库存管理到最后的发货车辆和路径优化管理等一系列的过程控制管理和协同管理的相关数据。结果：运用GPS/GIS技术,给出了科学合理的功能规划。结论：该系统规划从采购到货物配送一系列的无缝连接,极大的提高了社会生产率,节约了社会资源和配置。     

晶体形态稳定性研究进展

综述了８０年代至今的晶体界面形态稳定性的研究方法和内容,主要包括晶体形态稳定性与生长机制的关系,实时观察法研究晶体形态稳定性,扩散效应下的晶体形态稳定性研究以及对流效应对晶体形态稳定性的影响．     

磁场对KNbO3熔体中温度分布影响的实验研究

研究了磁场对ＫＮｂＯ_３熔体中的温度分布的影响．利用加磁场的休仑微分干涉显微实时观察装置及一种近似的间接测温方法,对在不同磁场强度０、７０、１１７、１３５ｍＴ下,ＫＮｂＯ_３熔体中的径向温度分布进行测量．发现随着磁场强度的增大,熔体中的径向温度梯度减小,尤其在坩埚－熔体界面附近,浮力驱动对流占主要作用的区域,温度梯度的减小更加明显．这可能是由于磁场对熔体中浮力驱动对流抑制的结果．     

抚顺辽五味子二维相关荧光光谱鉴别方法研究

目的 建立一种对抚顺辽产地的五味子快速识别方法的研究。方法 采用荧光分光光度计检测抚顺辽产地的五味子果实样品的三维荧光光谱,结合不同激发波长和发射波长彼此间波长间隔扰动下的二维相关荧光光谱技术。结果 本方法分析抚顺辽产地与其他产地的五味子的二维同步相关光谱的形状、自相关峰及交叉峰的出峰个数、位置、正负和强度等都存在明显不同。结论 抚顺辽产地与其他产地的二维相关荧光光谱差别十分明显和直观,可以作为抚顺辽原产地鉴别的一种有效方法。     

对流效应和溶质浓度对KNbO_3晶体界面形貌稳定性的影响

研究了在不同对流形态对ＫＮｂＯ３晶体生长形貌的影响．在温度梯度较小的扩散－平 流区域,晶体以枝蔓晶的形态生长;而在温度梯度较大的扩散－对流区域,生长出的晶体呈现 光滑晶面．通过测定不同区域ＫＮｂＯ３晶体界面附近的溶质浓度分布,从对流效应降低晶体界 面附近的溶质浓度分布的不均匀性的角度研究了对流效应对晶体界面形貌稳定性的影响,证明 对流效应提高了晶体界面形貌稳定性,与晶体界面弥散度的理论计算结果相一致．同时解释了 扩散－对流区域的晶体尺寸大于扩散－平流区域的晶体尺寸的原因．观察并定性地解释了不同 溶质浓度ＫＮｂＯ３形成不同的界面非稳定形貌,当 ＫＮｂＯ３重量百分比为２０ｗｔ％时形成骸晶, ３０ｗｔ％时形成枝蔓晶．     

Bi_(12)SiO_20熔体表面张力对流研究

利用高温熔体实时观察装置观察和研究了Ｂｉ１２ＳｉＯ２０熔体中表面张力对流从稳态向振荡态的转变过程;稳态过程中的对流图样变化;可能与对流转变有关的两个对流区域的交叉;振荡态对流的分叉现象．