图书馆读者网络问卷调查系统的设计与实现

本文为主要介绍,基于B／S结构,设计和开发网络版的读者问卷调查系统,此系统对调查问卷结果的分析和统计做出详细的描述,通过和图书馆其它系统的联合使用,形成特有的读者问卷调查反馈服务平台,本文参与“‘网络环境下高校用户信息行为实证研究”课题立项的研究。     

Machinability of Metal Matrix Composites Reinforced by 3-D Network Structure

Metal matrix composites reinforced by three-dimensional (3-D) continuous network structure reinforcement (3DCNRMMC) are difficult to machine due to serious tool wear and poor surface roughness caused by the brittle and hard reinforcement which interpenetrate into ductile matrix. In order to achieve the approach of low cost of 3DCNRMMC, the machinability of it needs to be understood. The influences of three cutting parameters and volume fraction of reinforcement on cutting force were analyzed in detail. The results indicate that: (1) Due to the brittle phase(s) introduced into ductile matrix of composites, there is a large fluctuation of cutting force causing deterioration of machinability. The fluctuation ranges of cutting forces, initially increase rapidly with the increase of volume fraction of reinforcement and then decrease finally, are largest at the range of the volume fraction of 55–65%; (2) The influence of cutting parameters on cutting force is obvious. With the increases of cutting speed, cutting force decreases gradually unless cutting speed exceeds the value of 209 m/min. Cutting forces increase with increasing feed rate and depth of cut; (3) Owing to the large fluctuation of cutting force, there were some cratered surfaces caused by Si₃N₄ reinforcement pulling-out and flaking-off. Some brittle phase protruding from the machined surface caused the deterioration of machined surface.     

DWDM上25.344 Mbit/s光监控信息传送系统的设计

采用25.344 Mbit/s光监控信息传送技术可以更好地满足当前密集波分复用(DWDM)系统中不断增加的网络监控信息和附加业务的需要.文章首先介绍了25.344 Mbit/s光监控信息传送系统的技术方案,然后详细描述了其帧结构、码型设计以及硬件实现的框图,最后介绍了该技术的优点.     

多线程技术在嵌入式数据采集系统中的应用

讨论了多线程技术在嵌入式数据采集系统中的应用，给出了PC机与嵌入式计算机系统的多线程串行通信的实现。     

模糊综合评判法在装备采购招标中的应用

根据我军武器装备采购招标的必要性和可行性，以及传统装备采购招标方法的局限性．详细阐述了在装备采购招标中运用模糊综合评判法进行评标的基本原理和主要步骤，并通过一个实例验证了模糊综合评判法在装备采购招标中的可行性和科学性。     

激光技术在微细加工中的应用

本文介绍了用于微细加工的激光器的种类和特点，阐述了激光技术在微细加工中的应用、国外的研制情况及其发展前景。     

粉煤灰贮存库气化装置存在问题及对策

描述了大唐国际陡河发电厂粉煤灰贮存库运行过程中出现出灰口下灰慢及气管中堵灰现象,清理灰库后发现气化板损坏、气化槽箱体内全部充满灰、分支进气管弯头磨漏、气化槽箱体安装工艺缺陷及原设计等问题,并对上述问题进行了分析,提出了解决问题的对策。通过对策实施,灰库气化装置运行效果良好,装灰速度提高了4.3~5.7倍。     

Improving the precision of optical metrology by detecting fewer photons with biased weak measurement

In optical metrological protocols to measure physical quantities, it is, in principle, always beneficial to increase photon number n to improve measurement prec...