高酸性气田压力容器无损检测

通过对压力容器四种常规无损检测方法进行分析对比,阐述了高酸性气田压力容器对接接头的无损检测方法和比例,在满足国内外现行标准规范的前提下,应加大超声波检测比例,对接触高酸性气体介质的焊缝内表面进行100%磁粉检测或渗透检测,最大限度地检测出焊缝内表面或近表面裂纹,确保高酸性气田地面建设工程的安全。     

Quadtree based colour quantisation image compression

A new colour quantisation and quadtree based image compression scheme is proposed. The features of the new scheme are that colour palette ordering and requantisation of the decoded image for palette-based monitor displays are not required. Thus, fast decoding and displaying can be achieved     

K终端可靠度分解算法中多边形→链简化定理的完善

无向网络K终端可靠度的分解算法中,包括多边形→链简化在内的等可靠度简化和分解定理结合,可以降低算法的复杂度。本文完善了边随机无向网络和混合随机无向网络的4#,6#,7#型多边形→链简化定理。计算机编程验证了其正确性。     

饮用水氯化中氯仿形成的动力学模式

以黄腐酸（ＦＡ）为卤仿前驱物质，分别测定不同投氯量、ＴＯＣ水平、温度以及ｐＨ值对ＣＨＣｌ３形成速率的影响，确定出ＣＨＣｌ３形成的动力学模式。该模式可用于预测投氯后的管网水中ＣＨＣｌ３的形成量，以便采取必要措施保证饮用水符合国家规定ＣＨＣｌ３〈６０μｇ／Ｌ的标准。     

添加尖晶石对氧化锌压敏电阻性能的影响

通过添加尖晶石（Ｚｎ７Ｓｂ２Ｏ（１２））改性研制出电位梯度为１００Ｖ／ｍｍ左右，压敏电压在８２～１５０Ｖ，通流容量可达１６００Ａ／ｃｍ２，漏电流＜２μＡ系列压敏电阻器，从而满足了国内电话交换机行业对８２Ｖ、１００Ｖ、１２０Ｖ、１５０Ｖ压敏电阻器的电性能要求。从工艺的角度解释了尖晶石对氧化锌瓷晶粒的作用原理，并分析了尖晶石的微观结构及粒度对瓷片电性能的影响。     

通过对一个旧战例的回顾看构筑物倒塌的抢险救援

通过北京火车站站前广告牌倒塌的抢险救援,阐述了构筑倒塌抢险救援的程序、方法及注意的问题。     

LD泵浦的Nd∶YAG腔内倍频激光器及其模式

用KTP晶体研制成LD泵浦的YAG腔内倍频激光器,得到0.532μm连续绿色线偏振激光输出,阈值泵浦功率为41mW,输出功率为1.4mW,斜效率为1.7％。研究了泵浦光对倍频激光横模的影响。     

基于AD650的模拟信号光纤传输系统的设计

在高电压、强磁场的强功率工况下,为了保护控制系统,须将测量系统和控制系统进行高低电位的隔离;采用电压频率(V/F)转换器AD650以频率形式通过数字光纤传输模拟信号,是高低电位隔离、远距离传输模拟信号而又不损失精度的最好解决方法;文中论述了其工作原理、系统组成,详细分析了硬件设计,并进行计算,确定其参数;实验结果表明,基于AD650芯片的传输系统,采用光纤传输,模拟信号传输精度小于0.1%,数据传输速率高,传输距离远,而且传输过程不受外界电磁场干扰,具有良好的线性度和分辨率;电路结构简单,对外界电容要求也简单,仅要求保持良好的稳定性,在实际工程应用中得到了优良的结果。     

Performance Evaluation of Range Queries in Key Value Stores

Recently there has been a considerable increase in the number of different Key-Value stores, for supporting data storage and applications on the cloud environment. While all these solutions try to offer highly available and scalable services on the cloud, they are significantly different with each other in terms of the architecture and types of the applications, they try to support. Considering three widely-used such systems: Cassandra, HBase and Voldemort; in this paper we compare them in terms of their support for different types of query workloads. We are mainly focused on the range queries. Unlike HBase and Cassandra that have built-in support for range queries, Voldemort does not support this type of queries via its available API. For this matter, practical techniques are presented on top of Voldemort to support range queries. Our performance evaluation is based on mixed query workloads, in the sense that they contain a combination of short and long range queries, beside other types of typical queries on key-value stores such as lookup and update. We show that there are trade-offs in the performance of the selected system and scheme, and the types of the query workloads that can be processed efficiently.