新型气体涡街流量变送器设计

设计了一种新型气体涡街流量变送器以简化测量系统结构,改善测量性能。变送器由信号测量单元与信号处理单元组成,测量单元同时对漩涡频率、被测气体温度和压力进行检测,信号处理单元以单片机为核心,通过软件对流量测量信号进行温度、压力补偿和非线性修正等处理以减少测量误差。实验测试结果表明:变送器性能指标达到了设计要求。     

可编程自动化控制器(PAC)--新一代的PLC

本文介绍了新一代的可编程自动化控制器(PACs)的概念、产生背景及现状，分析了其构成方式、技术优势，最后阐述了其应用前景及发展趋势。     

A Personalized Defection Detection and Prevention Procedure based on the Self-Organizing Map and Association Rule Mining: Applied to Online Game Site

Customer retention is an increasinglypressing issue in today's competitiveenvironment. This paper proposes a personalizeddefection detection and prevention procedurebased on the observation that potentialdefectors have a tendency to take a couple ofmonths or weeks to gradually change theirbehaviour (i.e., trim-out their usage volume)before their eventual withdrawal. For thispurpose, we suggest a SOM (Self-Organizing Map)based procedure to determine the possiblestates of customer behaviour from pastbehaviour data. Based on this staterepresentation, potential defectors aredetected by comparing their monitoredtrajectories of behaviour states with frequentand confident trajectories of past defectors.Also, the proposed procedure is extended toprevent the defection of potential defectors byrecommending the desirable behaviour state forthe next period so as to lower the likelihoodof defection. For the evaluation of theproposed procedure, a case study has beenconducted for a Korean online game site. Theresult demonstrates that the proposed procedureis effective for defection prevention andefficiently detects potential defectors withoutdeterioration of prediction accuracy whencompared to that of the MLP (Multi-LayerPerceptron) neural networks.     

Extraction of karyocytes and their components from microscopic bone marrow images based on regional color features

Extracting karyocytes and their components from microscopic bone marrow images is prerequisite for computer-aided early diagnosis of hemopathy. Most existing methods assume all pixels belonging to a karyon region or a cytoplasm region have similar colors. Practically, the color of neither a karyon nor a cytoplasm in a microscopic image is homogeneous in the pixel level. Therefore, the regional color features of a region are emphasized in this paper. Based on this observation, we propose a novel method to karyocyte extraction that first identifies a karyon by 4-connected block growing from a karyon feature block, then identifies feature blocks of its cytoplasm based on the extracted karyon, and finally extracts all cytoplasm regions by growing the cytoplasm feature blocks. Combining the karyon region and the corresponding cytoplasm regions can attain a complete karyocyte. Experimental results show that the proposed method is effective and robust.     

Lithium plasma emitter for collisionless magnetized plasma experiment

This paper presents a newly developed lithium plasma emitter, which can provide quiescent and low-temperature collisionless conditions for magnetized plasma experiments. This plasma emitter generates thermal emissions of lithium ions and electrons to produce a lithium plasma. Lithium type beta-eucryptite and lanthanum-hexaboride (LaB(6)) powders were mixed and directly heated with a tungsten heater to synthesize ion and electron emissions. As a result, a plasma with a diameter of ~15 cm was obtained in a magnetic mirror configuration. The typical range of electron density was 10(12)-10(13) m(-3) and that of electron temperature was 0.1-0.8 eV with the emitter operation temperature of about 1500 K. The amplitude fluctuations for the plasma density were lower than 1%.     

假单脉冲体制在LLX09雷达上的应用

本文着重介绍了假单脉冲体制在雷达上具体的实现方法，以及假单脉冲体制的原理和和差环信号的处理。     

空间凸轮廓面侧铣加工及最小二乘优化刀位方法

通过对空间凸轮非等价加工方式下理论刀轴轨迹曲面微分几何特性的研究，表明加工空间凸轮工作廓面必然存在法矢异向误差。为寻求加工误差最小的最佳刀轴矢量，提出了数控侧铣加工空间凸轮廓面的方法。根据实际刀轴轨迹面是直纹面的性质，以NURBS直纹面重构理论刀轴轨迹面，采用最小二乘优化方法确定侧铣加工刀位，给出了理论加工误差模型，并通过实例的数值计算和加工实验结果证明了该方法的有效性。     

微型热电发电器的性能测试分析

按照微型热电发电器输出功率的理论模型，对内阻、塞贝克系数和热导率等热电性能参数在不同温度范围内进行了测量和拟合。实验测试了不同电偶臂对数、电偶臂高度以及不同冷热端温度时微型热电发电器的最大输出功率，结果表明：一定范围内的最大输出功率随电偶臂高度的减小而增大，对电偶臂高度面积的比值进行适当选取，可使最大输出功率达到最优值；一定范围内的最大输出功率随电偶臂对数的增多而增大；温差和平均温度达到一定值时，最大输出功率可得到最优。根据测试分析结果，研制了微小型热电转换装置。     

铸件裂纹的预应力焊补

用一般焊接方法焊补有裂纹的铸件，待冷却后，焊缝处会产生很大的内应力。当焊缝金属本身承受不了这个内应力时，铸件在焊缝处便会产生新的裂纹，这样就不得不进行第二次第三次焊补，且焊补后铸件仍有产生新裂纹的可能。