抽汲井试井分析数学模型的建立及精确解

根据抽汲井试井工艺过程及其特点,采用已知上一次抽汲结束时的地层压力分布规律建立下一次抽汲数学模型的方法,建立了抽汲井试井分析数学模型,并在Laplace空间求解出了相应的精确解。将这一成果应用于长庆油田之中,结果表明:该理论能描述抽汲井的井底压力瞬变性及抽汲期井底压力变化无规律性的特征,符合实际测试工艺情况,弥补了抽汲井试井这一空白;提高了该类井试井的解释率和解释结果的可信度。同时,利用该理论还可计算抽汲过程中任一时刻的井底压力和关井时刻的井底压力,解决了抽汲井难以计算关井时刻井底压力的问题。     

Poverty and educational achievement in the US: A less-biased estimate using PISA 2012 data

In the current paper, we employ the most recent Programme for International Student Assessment (PISA) data to calculate a less-biased estimate of poverty on US achievement. The PISA was specifically chosen as it is an assessment removed from a specific curriculum and instead focuses on concepts that students should know in order to participate in a global economy. Using a propensity score matching approach, our findings suggest that US students in poverty have notable educational attainment deficiencies compared to a matched group of students who are not in poverty. In other words, when we select two students who have a great deal in common but for the fact that one comes from a poverty background, the student in poverty is expected to perform nearly 28 points, or about a quarter of a standard deviation lower, on the PISA assessment. In real terms, this puts math achievement for children not in poverty on-par with the Organisation for Economic Co-operation and Development (OECD) average, while children in poverty are well below the OECD average.     

Parental income and the fruits of labor: Variability in homework efficacy in secondary school

Research in the sociology of education has shown that noncognitive traits are important predictors of educational outcomes and a mechanism of the intergenerational transmission of status. However, previous research on this topic typically posits that there is a constant effect of these traits with variable prevalences of these traits by socioeconomic status. Using time spent on homework as an example, I analyze income-based heterogeneity in homework efficacy, defined as the individual effect of study time on academic achievement, using a national U.S. probability sample of secondary students. Higher income students gain more knowledge from their homework time than their counterparts in all grades and all subjects except history, with greater group differences for math than for science and reading. These results are confirmed by models accounting for time-invariant unobserved heterogeneity in the 8th–10th, but not 10th–12th, grade windows. These results imply that increases in the amount of homework assigned may increase the socioeconomic achievement gap in math, science, and reading in secondary school.     

Do peer effects mediate the association between family socio‐economic status and educational achievement?

Differences in levels of academic achievement according to socio‐economic status (SES), and parental education in particular, have been a persistent feature of Australian education systems. Young people with highly educated parents are more likely than their peers with low‐educated parents to attain high levels of achievement at school. Students with low levels of achievement are less likely than their high achieving peers to complete Year 12 and are more likely to experience negative post‐school outcomes. The SES of the neighbourhood, and in particular, the school attended, has also been found to have an effect on levels of both academic achievement and attainment. For this paper, we conduct analyses of National Assessment Program – Literacy and Numeracy test scores for four cohorts of secondary school students attending government schools in the Australian Capital Territory to examine the associations between parental education, school attended and levels of educational achievement. Our findings show that students with university‐educated parents achieve at much higher levels than their peers with low‐educated parents and that attending a school with a higher proportion of students from educationally disadvantaged families has a negative effect on educational achievement.     

分段启动压力对宝浪油田驱动压差的影响

摘要：渗透率低于 10 mD 的特低渗储层与平均渗透率大于 20 mD 的低渗储层开发技术政策界限和开发方案制定等有很大的差别，渗透率越低，其启动压力成倍增加，这就影响了开发技术和方案的制定。应用分段启动压力梯度进行分段计算并进行对比，计算结果表明：用同一启动压力梯度计算的结果不符合实际情况，而应用分段启动压力梯度计算的结果更能很好地反映特低渗储层的实际情况；井距对较高渗透率的驱动压力计算影响并不大，但对于特低渗储层的驱动压力计算则影响很大。     

The role of ethnic identity in school engagement: perceptions of immigrant Tibetan adolescents in select US public schools

This purpose of the study was to ascertain the level of ethnic identity formation and its perceived role on school engagement for Tibetan adolescents enrolled in public schools in two Midwestern states in the USA. The journey of these students from culturally encapsulated schools from Nepal, Bhutan, and India to multiculturally diverse settings was one of the most fascinating facets of the Tibetan Diaspora. Subjects included 16 girls, 25 boys, and 2 who did not identify their gender. The multigroup ethnic identity measure was used to determine the level of ethnic identity formation of Tibetan students while a questionnaire gathered information on school engagement. The overall ethnic identity measure for this sample was high with a mean of 3.58, while the cognitive and affective aspect of the measure was also high with a mean of 3.56 and 3.74, respectively. The girls showed more emotional commitment to ethnic identity, as their mean score was 3.92, while boys scored 3.62. The results clearly corroborated findings and conclusions drawn by other scholars. School and community partnership contributed to the healthy ethnic identity development of adolescents who were thus encouraged to be more engaged in meaningful school activities.     

基于ANSYS的压力容器表面凹坑缺陷安全评定分析

采用通用有限元程序ANSYS建立了移动式压力容器筒体外壁表面凹坑（轴向和周向）的有限元模型。结合筒体表面凹坑的应力理论计算，研究探讨了在恒定内压下，筒体表面凹坑缺陷处的应力分布与凹坑几何尺寸之间的关系。以第三强度理论作为仿真终止判据，获取凹坑各几何参量的阈值，利用MATLAB对阈值进行最小二乘拟合，绘制出凹坑缺陷的安全评估参考曲线。拟合结果表明：轴向和周向凹坑对筒体局部结构强度的影响不同，对应的安全评估参考曲线存在区别。     

Social network effects on academic achievement

How peer groups contribute to educational outcomes has long interested researchers. However, the possibility that peer groups dominated by either low- or high-achieving youth can have substantively different effects on achievement has been largely ignored. In this paper, we show that while being embedded in a high-achieving network of friends is not associated with increased own achievement, being embedded in a low-achieving network is associated with decreased own achievement. In additional analyses, we present evidence that these associations are at least in part due to influence, as opposed to only selection effects or shared environment. We also examine whether the structure of the network in which a student is embedded might affect their educational achievement. We show that achieving at higher levels positively predicts how centrally located a student is in their network, but being more centrally located does not predict concurrent achievement. This finding suggests that the behavior of individuals is affecting the formation of network structure and not the reverse.     

Fabulachia: urban,black female experiences and higher education in Appalachia

Abstract

This article draws on focus group conversations with black female college students attending a small, liberal arts institution in Kentucky. Based primarily on group interviews and discussions, as well as observations and analysis – a theoretical domain (referred to throughout the article as ‘Fabulachia’) emerged as a site-specific outcome of events and ideas regarding race, gender and identity experienced by the research participants. Specifically, ‘Fabulachia’ functions as a theoretical hybrid space in which urban (e.g. ‘ghetto fabulous’) black college student-voices find a sense of empowerment as they construct their own narratives of leaving ‘the hood’ to attend college in rural Appalachia. This project revises and updates previous research on race and rural identity/ies in order to situate the urban black female experience into an Appalachian context. Drawing on hip hop feminism and urban education based theoretical paradigms, the Fabulachia study seeks to give voice to black females in contemporary Appalachia, with attention to their self-proclaimed ‘ghetto fabulous’ identities honed in and through their urban upbringings. The unique experiences of (Fabulachian) black females are an important and largely absent part of larger conversations of the growing body of Urban education research that seeks to situate the black student/black youth and schooling experience in the US. In the Fabulachia study, a group of black female students shared personal narratives (part-oral history and part direct response) to prompts and queries about the role of hip hop culture, race and gender identity in their lives. They also discussed and debated what it means to be a black female in contemporary (often racist) Appalachia, and about how their families and urban surroundings influenced their processes of being and becoming in the context of higher educational achievement.     

特低渗透油藏 CO2 驱室内实验研究

针对大庆外围油田特低渗透油藏剩余油潜力大、井网加密效益差、水驱采收率低等问题，提出了特低渗透油藏 CO2驱技术。通过细管实验和天然岩芯 CO2 驱油实验，确定了 CO2 与高台子油田原油的最小混相压力，评价了特低渗透砂岩油藏 CO2 驱油效果。实验结果表明，CO2 驱可以应用于高台子油田，并取得较好的驱油效果。当天然岩芯空气渗透率为0.58 mD 时，在水驱基础上，气驱可以进一步提高采收率 8% 以上，特低渗透油藏实施 CO2 驱油技术是可行的。