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91.
92.
Investigations have been carried out on an erosion-corrosion apparatus to investigate the behaviour of corrosion-resistant highalloy iron-base materials containing hard phases. These materials had been optimized for increased wear resistance under complex stress conditions. As expected, in dry erosion tests, very low mass losses were established; there was little difference between the materials. Also, in corrosive environments (NaCl, H2SO4), the materials showed good stability; however, the duplex structures were superior to the martensitic ones. The combination of erosion and corrosion produced large differences and, in some cases, markedly reduced resistance to damage. These results confirmed observations that it is impossible to deduce the environmentally influenced mechanical behaviour of an alloy from its behaviour in separate corrosion and erosion experiments. The basic mechanisms underlying these processes have been investigated only tentatively. 相似文献
93.
Hispanic children are the fastest growing segment of the population. Numerous factors place them at-risk for school success. This study examined the effects of Child-Centered Play Therapy (CCPT) compared to a curriculum-based small group intervention with 29 Hispanic children referred for school counseling due to behavior problems. Children were assigned to treatment groups by random drawing within grade levels. Treatment was provided by Hispanic bilingual counselors. Statistical analysis revealed that, according to parent report, children receiving CCPT showed statistically significant decreases in externalizing behavior problems, compared to the curriculum-based treatment group. Effect size calculations revealed that CCPT demonstrated a large treatment effect on externalizing behavior problems and a moderate treatment effect on internalizing behavior problems. Cultural considerations and recommendations for practice and future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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研究了铸造WCP/Ni基合金梯度复合涂层组织与摩擦磨损特性。结果表明,梯度复合涂层与基材实现了良好的冶金结合,涂层内有γ-Ni枝晶组织,γ-Ni+M23C 6共晶组织以及凝固结晶析出的M6C、M23C6、M7C3等块状或条状组织;随着铸造WCP体积分数的增加,复合涂层摩擦系数减小,耐磨性增加。19-4试样的耐磨性最高值为4.61,是基材的3倍以上。梯度涂层的磨损机理为磨粒磨损与粘着磨损的复合作用。 相似文献
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本文对激光结晶a-Si∶H SOI结构砷注入和快速退火行为作了研究.a-Si∶H激光结晶有Lp-LCR,OD,FCR-2,FCR-1四个结晶区.用剖面电镜观察了结晶区的结构.扩展电阻测量表明Lp-LCR区中有两种扩散机制,即杂质在晶粒体内扩散和沿缺陷扩散.OD区中有三种扩散形式,除有上述两种以外,还有沿缺陷的扩散.首次比较了沿晶界和缺陷的扩散速度. 相似文献
99.
Dr Joseph A. Cannataci 《AI & Society》1989,3(3):169-183
This paper examines some of the possible legal implications of the production, marketing and use of expert systems. The relevance of a legally useful definition of expert systems, comprising systems designed for use both by laymen and professionals, is related to the distinctions inherent in the legal doctrine underlying provision of goods and provision of services. The liability of the sellers and users of, and contributors to, expert systems are examined in terms of professional malpractice as well as product liability. A recurring theme indicates that legislators may be inclined to restrict possibilities of liability suits in order to avoid disincentives to the creation of expert systems. 相似文献
100.
以Bi(NO3)3·5H2O和Ti(OC4H9)4为原料,NaOH为矿化剂,采用水热法制备了形貌规则的单晶Bi4Ti3O12纳米片。X射线衍射(XRD)结果表明,所合成的产物为正交相层状钙钛矿结构的Bi4Ti3O12。场发射扫描电子显微镜(FESEM)研究显示:样品是由大量边缘尺寸接近200nm,厚度约为15nm的片状结构组成。利用X射线光电子能谱(XPS)研究产物的化学组分和价态分布。室温拉曼光谱研究表明,Bi4Ti3O12纳米片的声子寿命和热稳定性低于相应的块体材料。 相似文献