晶闸管铝镓闭管扩散工艺的计算机模拟

为了对晶闸管特性进行计算机模拟,有必要对其P区的杂质浓度分布建立准确而便于计算的模型。文中对形成P区二段式杂质分布的铝镓分步闭管扩散工艺进行了讨论。对较低浓度铝的最终分布着重考虑它在扩镓过程中的再分布,而对高浓度镓的最终分布则着重考虑扩散系数的变化。与实验样品的扩展电阻探针测试数据进行比较后表明,本工作所用模型与实验结果有较好的吻合,适宜于在实际工艺过程中使用。     

一种柱球头铣刀新型刃口的数学模型

通过对传统柱球头铣刀传统刃口设计中数学模型的推导与分析，指出了传统方法设计与制造中存在较大困难，提出了介于与径线成定角ψ和等螺距刃口之间的新设计方法，并给出了二轴联动和非数控加工的方案与数学模型，为这类同是较大的回转刀具的研制提供了新的参考。     

A New Paradigm for the Extraction of Information: Application to Enhancement of Visual Information in a Medical Application

IntroductionThenoninvasiveassessmentofthecardiacfunctionisofmajorinterestforthediagnosisandthefollowupofcardiovascularpathologies.WhereascardiacMRIonlyallowstomeasureanatomicalandfunctionalparametersofmyocardium,taggedcardiacMRImakesitpossibletoevaluatetheintramyocardialdisplacement.Therefore,itallowstheanalysisoftheregionalcontractionofthemyocardium(detectionofpotentialcontractibleareaswithintheinfarctedareaasitshownby[8]).TheSPAMM(SpaceModulationofMagnetization)acquisitionprotocol[11]u…     

Partial oscillation of m -dimensional logistic ecologic models

We present and discuss the partial oscillation with respect to equilibrium state ofm-dimensional Logistic delay ecologic models, and obtain some simple criteria. Supported by the Youth Development Foundation of Wuhan Yejin University of Science and Technology (1997) Luo Qi: born in 1958, Associate professor     

“It was Hard to Come to Mutual Understanding …”—The Multidimensionality of Social Learning Processes Concerned with Sustainable Natural Resource Use in India, Africa and Latin America

Sustainable natural resource use requires that multiple actors reassess their situation in a systemic perspective. This can be conceptualised as a social learning process between actors from rural communities and the experts from outside organisations. A specifically designed workshop oriented towards a systemic view of natural resource use and the enhancement of mutual learning between local and external actors, provided the background for evaluating the potentials and constraints of intensified social learning processes. Case studies in rural communities in India, Bolivia, Peru and Mali showed that changes in the narratives of the participants of the workshop followed a similar temporal sequence relatively independently from their specific contexts. Social learning processes were found to be more likely to be successful if they 1) opened new space for communicative action, allowing for an intersubjective re-definition of the present situation, 2) contributed to rebalance the relationships between social capital and social, emotional and cognitive competencies within and between local and external actors.     

硬车削技术及其应用

分析了硬车削加工的特点、硬车削加工所需的条件以及硬车削技术在生产中的应用，并对其关键技术进行了探讨，指出理车削技术是一种高效、洁净的工艺方法，具有广泛的应用前景。     

钢-半固态Al-7石墨复合界面特性

为了开发高温钢铝轴瓦材料,采用铸轧技术进行了钢板与Al-7石墨半固态浆料的复合实验,得到了不同于常规钢铝复合产品的界面结构。结果表明:在钢板预热温度为510℃、Al-7石墨半固态浆料固相率(体积分数)为32%的条件下,随着扩散时间的增加,复合界面上生成的铁铝化合物逐渐增多;当扩散时间大于35s时,复合界面完全由铁铝化合物构成;当扩散时间为22.5s时,可形成由铁铝化合物和铁铝固溶体交替构成的新型结构,其界面力学性能较好。     

随机环境SMDP的弱收敛逼近

在随机环境半马氏决策过程的计算方法中,直接从最优方程求最优策略或求ε最优值函数都会遇到困难,本文讨论的弱收敛逼近提供解决这类问题近似计算的一种方法     

RLW方程的经济型差分-流线扩散法

对线性RLW方程提出了一种经济型差分-流线扩散法,分析了该方法的稳定性和收敛性,得到了L2模拟丰满误差估计和H 1模丰满误差估计.     

氮化层组织与干式滚动磨损性能的研究

本文利用X光衍射仪、金相显微镜和声发射等手段对38CrMoAlA,35CrMo,40Cr钢经纯氨离子氮化,纯氨加钛离子氮化以及气体氨化后的渗层组织,硬度及干式滚动磨损性能进行了观察和分析。结果表明:加钛离子氮化可以显著提高工件渗层的硬度;但由于脆性增加而不利于干式滚动磨损;离子氮化处理后抗干式滚动磨损性能最佳。