A web-based self-testing system with some features of Web 2.0: Design and primary implementation

Self-testing is a means to check learning effect. Besides time–space restriction, there are many deficiencies in traditional offline self-testing. With the development of information technology, learners can have self-testing on the Internet. Self-testing on Internet, namely, web-based self-testing, overcomes time–space limitation of traditional offline self-testing, but there are still several disadvantages such as monotony and lack of interaction. In the article, a web-based self-testing system with some features of Web 2.0 is designed and implemented, aiming at overcoming the weaknesses of current online self-testing system. Firstly, taking English self-testing as an example, the framework of the system and functions of its main modules is designed according to theories of social learning and constructivism as well as the idea of Web 2.0 and the characteristics of server-side programming. Secondly, in accordance with the design above, a new system is implemented for English learners primarily by using HTML, JavaScript, PHP, and MySQL comprehensively. The role and duty of webmaster are also described briefly. To test the system, some English learners were invited randomly to use it, and feedback information was collected from them after a period of time. It is shown by feedbacks that most learners are satisfied with the system, and the system is of distinct features and favorable practicality compared with other systems, but it still needs to be improved in the design of user interface and some other details. Results in the article demonstrate that the new system can overcome the shortcomings of current systems to some extent.     

Windows NT/95是实时控制系统较理想的平台

该文将DOS与Windows NT/95作一简单比较,并通过NT/95下实时控制系统应用的几个实例,从实时控制系统所要求的几方面阐述了NT/95在该领域作为操作平台的可行性。     

木结构双自攻钉协同抗拔力试验研究

为了研究木结构中的自攻钉的抗拔性能,选用中国产普通圆钉、进口规格木材和普通木材,制作了6个木结构剪力墙中钉连接的试件,采用单调加载方式进行试验研究,结果表明普通圆钉连接强度主要取决于破坏模式;契入效应不足明显影响钉连接的强度;钉连接刚度离散性较大;故而通过进一步的试验研究,得出中国产自攻钉抗拔连接强度和刚度计算公式,将是十分必要的。     

努力改变现状 提高档案利用率

企业档案不齐全、不完整，档案部门缺乏资金，封闭保守、等客上门的思想意识和工作作风等现状是当前企业档案利用率不高的主要原因。企业档案部门应采取措施，提高企业档案利用率，为企业领导决策提供依据，为生产经营服好务。     

基于数量化II类的数据分析库的设计与实现

数量化II类理论研究的是定性资料的分析,它与判别分析根据所研究的个体的观测指标来推断该个体所属类型的方式不一样。文章以数量化II类作理论依据,采用定性分析与定量分析相结合的方法,提出了一种数据分析库的设计和实施方案,该系统在数据分析和决策支持系统方面的研究和应用中有一定的特色。     

EMS系统分布式数据库数据复制的设计与实现

本文通过一个能量管理系统剖析了分布式数据库复制的设计思想和具体实施的方法。     

Effect of Friedel–Crafts reaction on the thermal stability and flammability of high‐density polyethylene/brominated polystyrene/graphene nanoplatelet composites

Brominated flame‐retarded high‐density polyethylene (HDPE) composites containing graphene nanoplatelets (GNPs) were prepared via melt blending. A Lewis acid catalyst, anhydrous aluminium chloride (AlCl₃), was added to initiate Friedel–Crafts reaction for promoting the dispersion of the GNPs in the polymer matrix. Transmission electron microscopy images and Raman spectroscopy revealed that the GNPs were partly unfolded and the domains became smaller in the presence of AlCl₃. Limiting oxygen index and microscale combustion calorimetry showed that the incorporation of AlCl₃ into HDPE reduced flammability and slowed down the heat release rate. Thermogravimetric analysis and char residue measurements proved that a uniform dispersion of GNPs was crucial for forming a continuous and compact carbon layer, thus isolating the underlying materials from flame and preventing heat transfer. Rheological and mechanical tests indicated that interfacial adhesion between polymer chains and GNPs was enhanced. © 2014 Society of Chemical Industry     

Synchronization for IR‐UWB System Using a Switching Phase Detector‐Based Impulse Phase‐Locked Loop

Conventional synchronization algorithms for impulse radio require high‐speed sampling and a precise local clock. Here, a phase‐locked loop (PLL) scheme is introduced to acquire and track periodical impulses. The proposed impulse PLL (iPLL) is analyzed under an ideal Gaussian noise channel and multipath environment. The timing synchronization can be recovered directly from the locked frequency and phase. To make full use of the high harmonics of the received impulses efficiently in synchronization, the switching phase detector is applied in iPLL. It is capable of obtaining higher loop gain without a rise in timing errors. In different environments, simulations verify our analysis and show about one‐tenth of the root mean square errors of conventional impulse synchronizations. The developed iPLL prototype applied in a high‐speed ultra‐wideband transceiver shows its feasibility, low complexity, and high precision.     

Electrospinning and Imaging

Polymer processing via electrospinning is a cost effective and scalable method for preparing nanofibers with industrial, electrical, and biomedical applications, particularly tissue engineering and drug delivery. Characterization methods for these fibers include microscopy techniques for vitro surface morphology information, spectroscopy methods to determine in vitro chemical composition, and medical imaging tools for in vivo assessment of morphology and efficacy of implanted material. The focus of this paper is be on recent applications for electrospun nanofibers, in vitro characterization methods, and medical imaging modalities that can be used for in vivo assessment of the fibers, as well as insights in how to adapt existing techniques toward the characterization of electrospun materials.