气力输送装置在铸造制芯系统中的应用

随着冷芯机的发展与普及,采用气力输送装置以其全密封、适应环保的要求而成为与冷芯机配套的首选设备。近年来江阴华澳机电设计研究所有限公司(以下简称江阴华澳)先后给洛阳一拖铁一、铁二、一汽锡柴、广西玉柴、上柴、二汽铸一等单位配套了冷芯机气力输送装置。下面以广西玉柴机器股份有限公司(以下简称玉柴)的气力输送装置为例,介绍制芯机与其配套气力输送装置的技术设计及使用情况。2002年玉柴开始新建第二铸造车间,其中制芯工部选用了两台德国H ottinger公司的90L冷芯机和两台苏州明志铸造装备有限公司的65L冷芯机。H ottinger公司的…     

Identifying extract class refactoring opportunities for internetware

The quality of internetware software is significantly associated with class structure.As software evolves,changes often introduce many unrelated responsibilities to the same classes or distribute tightly-related methods in different classes.These changes make the classes difficult to understand and maintain.Extract class refactoring is an effective technique to improve the quality of software structure by decomposing unrelated methods in one class to create new classes or extracting tightly-related methods from different classes.In this paper,we propose a novel approach for class extraction from internetware source codes.This approach leverages a community structure detection technique to partition software into clusters and extracts classes from the resulting clusters.Our experimental results,which investigate the public well-known internetware PKUAS,indicate that:(1)the proposed approach is much faster than existing search-based clustering approaches(Hillclimbing and Genetic algorithm)and is thus applicable for large-scale internetware;(2)the proposed approach can identify meaningful class extractions for internetware;and(3)Extract Class refactoring candidates identified by the proposed approach significantly improve class cohesion of internetware.     

A low-energy ion spectrometer with half-space entrance for three-axis stabilized spacecraft

A low-energy ion spectrometer(LEIS) for use aboard three-axis stabilized spacecraft has been developed to measure ion energy per charge distribution in three-dimensional space with good energy-, angular-and temporal-resolutions. For the standard top-hat electrostatic analyzer used widely in space plasma detection, three-axis stabilized spacecraft makes it difficult to obtain complete coverage of all possible ion arrival directions. We have designed angular scanning deflectors supplementing to a cylindrically symmetric top-hat electrostatic analyzer to provide a half-space field of view as 360°×90°(–45°–+45°), and fabricated the LEIS flight model for detecting magnetospheric ions in geosynchronous orbit. The performance of this payload has been evaluated in detail by a series of simulation and environmental tests, and the payload has also been calibrated through laboratory experiments using a low-energy ion source. The results show that capabilities of the LEIS payload are in accordance with the requirements of a magnetospheric mission.     

基于IKE的安全远程接入

为了解决在主机IP地址不固定的情况下如何保证网络的安全性问题,介绍了IKE利用经典认证机制来支持外部接入的各种方法,详细阐述了各种方法的工作原理和优缺点,并对它们的适用环境做了分析,说明在IP地址不固定的网络中,IKE也可以提供良好的安全服务。     

JCZ型转矩转速传感器输出信号的相位差检测方法

讨论在某汽车变速箱加载测试系统中对JCZ型转矩转速传感器输出信号的处理方法.文中给出相位差检测电路和信号处理算法的方法,分析检测电路中各节点的信号波形和检测电路输出波形.实际应用表明,该方法的测量结果准确、稳定、可靠.     

Segmentation of fuzzy images: a novel and fast two-step pseudo MAP method

This paper presents a new two-step pseudo maximum a posteriori (MAP) segmentation method for the Markov random field (MRF)-modeled image because the exact MAP estimation is hard to implement due to intractable complexity. The expectation maximization (EM) and Markov Chain Monte Carlo (MCMC) methods are adopted to estimate the parameters for the MRF model due to their comparatively good performance. Although the image segmentation algorithms via graph cuts have become very popular nowadays, our proposed algorithm still performs significantly better in automatic identification and segmentation of fuzzy images than them, which is shown by the quantitative results on synthesized images. In practical applications, the proposed two-step pseudo MAP method is superior in segmenting the fuzzy laser images reflected from the weld pool surfaces during the P-GMAW welding process.     

4H-SiC trench gate MOSFETs with field plate termination

Field plate(FP)-terminated 4H-SiC trench gate MOSFETs are demonstrated in this work.N+/P?/N?/N+multiple epitaxial layers were grown on 3-inch N+type 4H-SiC substrate by chemical vapor deposition(CVD),and then the 4H-SiC trench gate MOSFETs were fabricated based on the standard trench transistor fabrication.Current-voltage measurements in forward and reverse bias have been performed on different devices with and without FP protections.It is found that more than 60%of the devices protected with FP termination are able to block 850 V.The measurements also show that the devices have the small leakage currents 0.15 nA at 600 V and 2.5 nA at 800 V,respectively.The experimental results also were compared with the simulated results,which show good agreement with each other in the trend.The limited performance of the devices is mainly because of the damage induced on the trench sidewalls from the etching process and the quality of the SiO2 films.Therefore,the 4H-SiC trench gate MOSFETs are expected to be optimized by reducing the etching damage and growing high-quality SiO2 dielectric films.     

制备四氯化钛过程中加碳氯化反应热力学

反应热力学对研究二氧化钛加碳氯化反应具有指导作用。运用HSC软件通过计算对二氧化钛加碳氯化的CO／CO2比值、配碳比等进行了讨论,结果表明低温下加碳氯化反应的相关产物为CO2,而高温下为CO。产物TiCl4含量在整个温度范围内保持稳定。当配碳比较高时,碳的反应不完全,存在过量;较低时,不利于TiO2的完全反应。通过对工业TiCl4生产CO／CO2 比值研究,发现CO／CO2比值不完全与平衡态下的CO／CO2比值一致。同时对低价钛氧化物的生成进行了探讨,计算表明在温度低于1 100℃时不会生成低价钛氧化物。通过以上研究为进一步优化加碳氯化反应提供了依据。