热氧化法钝化硅片的少数载流子寿命

用高频光电导衰减法 (PCD)研究了热氧化钝化对直拉硅少子寿命的影响 .在 70 0～ 110 0℃范围热氧化不同时间 (0 .5～ 4 h)对直拉硅片表面进行钝化 ,实验结果表明 ,在 10 0 0℃下热氧化对硅片表面钝化的效果最好 ;而且发现热氧化 1.5 h后硅片的少子寿命值达到最大值 ,接近于其真实值 ,而随着热氧化时间的延长 (>1.5 h)少子寿命将会降低 ,这是由于直拉硅中过饱和的氧会沉淀下来形成氧沉淀 ,成为新的少子复合中心 .     

大直径直拉硅中氮对原生氧沉淀的影响

研究了在大直径直拉硅单晶中掺氮 (N )对原生氧沉淀的影响 .通过高温一步退火 (10 5 0℃ )和低 -高温两步退火 (80 0℃ +10 5 0℃ )发现在掺 N直拉 (NCZ)硅中氧沉淀的行为与一般直拉 (CZ)硅是大不相同的 ,经过高温一步退火后 ,在氧化诱生层错环 (OSF- ring)区氧沉淀的量要小于空洞型缺陷 (voids)区 ,而经过低 -高温两步退火后 ,OSF-ring区的氧沉淀量要远远大于 voids区 .由此可得 ,在晶体生长过程中 ,N通过改变硅晶体中空位的浓度及其分布从而改变原生氧沉淀的尺寸和分布 .并在此基础上讨论了在大直径 NCZ硅中掺 N影响原生氧沉淀的机理 .     

Gender-schematic processing in children: The role of initial interpretations of stimuli.

When processing gender-related information, children have difficulty remembering materials that are counterstereotypic or that are associated more strongly with the other sex. The question of whether encoding difficulties account for these memory problems was investigated. Children (kindergarten through Grade 3) were shown pictures of men and women in traditional, nontraditional, or neutral roles. Some children were given stimulus labels at acquisition to simplify the encoding task. Free-recall data revealed biases in the direction of gender stereotypes, irrespective of label vs no-label conditions (Studies 1 and 2) and of slower vs faster presentation rates (Study 2). Results suggest that an inability to encode at acquisition is probably not the major cause of gender-related biases observed in later recall and have implications for the development of intervention programs designed to reduce gender-schematic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Race and the workforce: Occupational status, aspirations, and stereotyping among African American children.

This study examined whether African American children's perceptions of occupational status and their own vocational interests are affected by racial segregation of the workforce. Children (N = 92) rated familiar occupations with respect to status, desirability, and stereotyping. Children also rated novel jobs that had been depicted with African Americans, European Americans, or both African and European Americans. As predicted, for familiar jobs, children's judgments were linked to their knowledge of racial segregation of these jobs. In addition, novel occupations that had been depicted with African Americans were judged as lower in status than the identical occupations that had been depicted with European Americans, demonstrating a causal influence of workers' race on children's judgments. Children's age and socioeconomic background moderated their occupational judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

CPG500型长轨条铺轨机组牵引驱动系统设计研究

文章介绍了CPG500型长轨条铺轨机组的牵引驱动系统,该系统可提供在12‰坡道上机组牵引重量达2500t时的牵引力,同时具有动轴防滑、履带式和动轴牵引装置牵引力比例调节及同步的功能,且低速稳定性好。     

水滑石/LLDPE无卤阻燃复合材料的阻燃性

研究了以水滑石(LDHs),微胶囊化红磷(MRP)、三氧化二锑(Sb2O3)和二茂铁(FC)复配得到的复合阻燃剂对线形低密度聚乙烯(LLDPE)复合材料性能的影响.分别通过氧指数、水平燃烧和力学性能测试考察了复合材料的阻燃性能和力学性能.结果表明,当LLDPE/乙烯醋酸乙烯共聚物(EVA)/LDHs/MRP/Sb2O3/FC/过氧化二异丙苯(DCP)质量比为60/40/48/17/5/5/0.7时,复合材料的氧指数达到34.5%,阻燃级别为FH-1;断裂伸长率为225%,拉伸强度达10.9 MPa.     

Isothermal dehumidification with a simply thermoelectric device: concept and feasibility

This paper proposed a simple thermoelectric cooler (TEC) device with a heat recovery unit to deliver isothermal dehumidification in a small space where ambient temperature falls into the comfort zone while relative humidity is high. The concept of the system was presented, followed by the analysis of the cold surface temperature to examine its possibility to reach the target. Five different types of TEC products were chosen to make a comparison by using the market available data sheets and results found that for small applications (up to 30?W), the proposed system can easily deliver the isothermal dehumidification with room temperatures of 20–25°C.     

高碳CZ硅中氧沉淀的两种成核长大机制

应用红外光谱、高分辨透射电镜研究了高碳CZ硅中的氧沉淀．实验表明：高碳样品中有两种成核长大机制形成的氧沉淀,一是多碳中心的异质成核长大的氧沉淀,碳原子同时参与氧沉淀的成核和长大,红外光谱上1230cm－1处无氧沉淀的特征峰,TEM观察这种氧沉淀是10～30nm高密度的球状小沉淀;另一种氧沉淀类似于低碳样品中均匀成核长大的氧沉淀,它在红外光谱上1230cm－1处有吸收峰,TEM观察这种氧沉淀是100～300nm各种形态的大沉淀．热处理条件不同可以改变两种机制相互竞争的优势,低于900℃的热处理以异质成核为主,而只有经过1200℃高温预处理破坏异质核心后,再在900℃以上热处理时,均匀成核长大的氧沉淀才会占优势．     

重掺杂直拉硅单晶氧沉淀及其诱生二次缺陷

研究了重掺杂直拉硅单晶中掺杂元素硼、磷、砷、锑对氧沉淀及其诱生二次缺陷行为的影响 .实验结果表明 :重掺p型 (硼 )硅片氧沉淀被促进 ,氧沉淀密度高但无诱生二次缺陷 ;重掺n型 (磷、砷、锑 )硅片氧沉淀受抑制 ,氧沉淀密度低却诱生出层错 ;不同掺杂元素及浓度对重掺n型硅片氧沉淀抑制程度不同 ,并对氧沉淀诱生层错的形态产生影响 .讨论了重掺硅单晶中掺杂元素影响氧沉淀及其诱生二次缺陷的机理 ,并利用掺杂元素 本征点缺陷作用模型和原子半径效应模型对实验结果进行了解释 .