公路沥青面层施工中离析原因分析及防治措施     

张旭升 《石家庄铁路职业技术学院学报》2007,6(4):64-66

通过在207线公路沥青混凝土路面面层施工实践经验，对沥青混凝土面层施工中出现局部离析的原因进行分析，并从基层施工、沥青混合料配合比和矿料级配、拌和、运输、摊铺及压实等方面提出改进措施。  相似文献   

Reading and listening progress in segregated primary schools: Does ethnic and socioeconomic classroom composition matter?          下载免费PDF全文

Lisa Dewulf  Johan van Braak  Mieke Van Houtte 《British Educational Research Journal》2017,43(5):931-951

This study aimed to investigate the relationship of classroom composition factors with reading and listening comprehension achievement and progress in socially and ethnically segregated primary schools in Flanders (Belgium). Specifically, using a three‐level multivariate repeated measures analysis, it examined the association of reading and listening achievement and progress with ethnic diversity, the proportion of non‐native students and the average socioeconomic status of the class, taking into account student characteristics. At the beginning and end of the school year, reading tests, listening tests and questionnaires were administered to a sample of 7‐ and 8‐year‐old students (n = 683) in 42 second‐grade classes. Students' listening comprehension achievement at the beginning of the school year was negatively related to having a home language other than the language of instruction and to classes with a high proportion of non‐native students. However, progress in listening comprehension was not significantly associated with any student or classroom composition factors. Students whose mothers had a lower level of education performed lower on reading comprehension at the beginning of the school year, while at the end of the school year students whose mothers had a higher level of education were at a greater disadvantage. Limitations of this study and directions for future research are discussed.  相似文献   

A different type of charter school: in prestige charters,a rise in cachet equals a decline in access   总被引：1，自引：0，他引：1  

Elizabeth Brown  Molly Vollman Makris 《教育政策杂志》2018,33(1):85-117

This paper seeks to elucidate a specific type of charter school. While much has been written about school choice and the expanding charter school segment, a growing and important number of charter schools do not fit in to the common understanding of these schools. Distinct from many of their counterparts, prestige charter schools have the following two features: elements which foster a reputation similar to that of elite private schools and a student population demographically distinct from local public district schools – whereby the prestige charters serve a disproportionate number of advantaged families. The prestige elements include: founding by advantaged community members; parental involvement; wait lists; popularity with advantaged professionals; high test scores; and niche themes. The authors will show through two in-depth case studies that prestige charter schools work hand-in-hand with gentrification in urban neighborhoods, and result in racial and class segregation and inequality. This paper examines how these charter schools struggle when a rise in prestige coincides with a decline in access for low-income students. The authors recommend that given the current system of school choice, prestige charter schools must use tools and mechanisms to maintain demographic diversity and educational equity which is in the best interest of all children.  相似文献   

半导体锗纳米团簇和纳米层的生成结构与PL谱研究     

黄伟其  刘世荣 《贵州教育学院学报》2003,14(4):34-38

在硅锗合金衬底上采用氧化等制膜方式生成零维和二维的纳米结构样品，用高精度椭偏仪(HPE)、卢瑟福背散射谱仪(RBS)和高分辩率扫描透射电子显微镜(HR—STEM)测量样品的纳米结构．并采用美国威思康新州立大学开发的Rump模拟软件进行精细结构模拟．并测量出样品横断面锗纳米团簇和纳米层的PL谱。在硅锗合金的氧化层表面中首次发现纳米锗量子点组成的几个纳米厚的盖帽膜结构．首次提出的生成硅锗纳米结构的优化加工条件的氧化时问和氧化温度匹配公式的理论模型与实验结果拟合得很好．  相似文献   

Conflicts,competition and social support in female-dominated vocational education – breaking or reaffirming stereotypical femininity?     

Kristinn Hegna 《Journal of Vocational Education & Training》2017,69(2):196-213

One in four upper secondary school students in Norway experience nearly single-sex classrooms, an unintended consequence of choosing certain vocational study programmes, such as Health care, childhood and youth development or Building and construction. This raises a question about how female students describe their experiences of social relationships and classroom culture within the context of a gender-segregated vocational education setting. Analyses of educational biography interviews reveal that stories of conflict, competition and cultural differences dominate and are often described using derogative or gendered language, such as ‘bitching’, ‘gossip’ and ‘drama’. These stories demonstrate a break with gender stereotypes but, at the same time, accentuate femininity by aligning the behaviour to stereotypical discourses of ‘girl’ behaviour. In their stories, gender loses its importance as a basis for solidarity and commonality when students share the same gender; instead, hierarchies and other differences become highlighted.  相似文献   

From learning to labour to learning for marginality: school segregation and marginalization in Swedish suburbs     

Dennis Beach  Ove Sernhede 《British Journal of Sociology of Education》2011,32(2):257-274

In this article, using data from ethnographic research, we try to present some glimpses of the way education is described as an experience and possibility ‘from below’, by pupils who grow up and study in schools in the most segregated and territorially stigmatized suburbs on the outskirts of our major cities. What we feel they describe is an experience of schooling for surviving the social and economic consequences of curtailed citizenship in a post‐industrial society rather than one of schooling that offers possibilities of integration and full citizenship or social transformation. Our findings have significant policy implications in this respect. Sweden has historically pursued projects aimed at educational inclusion but has recently taken a significant turn toward neo‐liberalism and educational consumerism, since which time various disadvantaged groups have become increasingly concentrated compared with others in under‐achieving schools in an economically threatened public sector. The article discusses some aspects and possible consequences of this development.  相似文献   

离合词的成因和离析理据     

杨蕾 《桂林师范高等专科学校学报》2011,25(4):107-109,129

离合词的存在,有着社会历史的客观基础和根本原因,它是汉语自身发展中出现的一种不可避免的语言现象．言语交际和语言表达的需要,以及汉语词汇的不断丰富和发展使得离合词这一现象必将长期地存在,并深刻影响着汉语体系和汉语交际．对于这一语言现象,我们必须正视它的存在,及时描写和分析,不断总结其规律,而高合词的成因和离析理据无疑是最好的研究导向．  相似文献   

Q55OD高强板断口分离缺陷的微观分析     

关云  邓照军  陈庆丰  马家艳 《武汉工程职业技术学院学报》2013,(4):43-45

Q550D高强板在进行室温拉伸试验后,断口出现分离缺陷。通过扫描电镜、金相显微镜、透射电镜对其断口及分离面的微观形貌、分离裂纹末端及远离裂纹的断口横截面组织及亚结构等进行了观察分析。结果表明：拉伸变形前,组织为贝氏体＋碳化物,部分晶界及碳化物周围有位错塞积,但不存在裂纹。拉伸变形时,贝氏体晶界及亚晶界呈链状分布的大尺寸渗碳体颗粒附近的位错塞积引起应力集中,形成微裂纹及孔洞;同时,拉伸断口的颈缩变形引起垂直于拉伸轴方向产生新的拉应力,导致微裂纹及孔洞在拉伸轴方向优先扩展形成裂纹;这两者成为产生分离缺陷的主要原因。分离裂纹的长度与裂纹扩展时的应力状态及组织变形程度有关。  相似文献   

Determinants of Primary School Choice in Malaysia: School Proximity and Ethnicity-Related Reasons     

Su-Hie Ting  Diana Phooi-Yan Lee 《Journal of School Choice》2019,13(2):228-254

The study examined determinants of primary school choice among parents in Malaysia, and the decision maker and social influences in the school choice. It draws on qualitative data from semi-structured interviews with 43 middle-class parents from three ethnic groups (Chinese, Malay, and Indigenous). Results showed that school proximity and ethnicity-related reasons are leading factors influencing parental school choice. Medium of instruction, school academic reputation, and feeder to a preferred secondary school appear to be separate reasons but act as a proxy to ethnicity as the primary factor determining the choice of Chinese- or Malay-medium primary school by parents. The results also showed that mothers are more likely to make school choice decisions than fathers, but the reasons for school choice are similar. The primary social influences on their school choice come from friends and education personnel in preschools and schools. The Indigenous parents tend to be more subject to social pressure in making school choices than the Chinese and Malay parents, who mostly enroll their children in Chinese- and Malay-medium primary schools, respectively. However, these findings on school choice and ethnic segregation are limited to this sample and constrained by the socio-political context of the education system.  相似文献   

唯一真正的美国人--印第安人     

李明 《河北北方学院学报(社会科学版)》2002,18(1):52-54

美国是个多民族国家,印第安人是其中一个少数民族,人口约140万.他们是美国最早的居民,为美洲的开发,为美国的发展作出了重大贡献.然而,美国历届政府对他们一直采取种族灭绝、隔离和同化政策,人为地使其丧失公民权,沦为社会最低层.美国是最没有人权的国家.  相似文献