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1.
孙建永 《中国石油大学胜利学院学报》2011,25(2)
针对出砂油井进行酸化解堵作业易加剧油井出砂的问题,研制一种具有解堵和抑砂双重性能的HKL新型解堵抑砂剂,对解堵抑砂剂的作用原理进行研究,并对配方组分进行优化,对抑砂剂性能进行评价,结果表明,HKL解堵抑砂剂保持了无机解堵剂的溶蚀性,同时在砂粒表面形成的体型高分子膜可增加岩石胶结强度,使解堵抑砂剂起到了抑制地层出砂的作用。 相似文献
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王勇 《中国石油大学胜利学院学报》2012,26(2):15-17
针对胜利油区防砂低效井解堵后由于地层中粉细砂的运移造成生产有效期较短的问题,研制了一种新型的深部高效稳砂剂(简称SA-1)。简述了SA-1的分子结构设计和稳砂作用机理,并通过室内实验对SA-1的物化性能进行了评价,现场应用4口井,明显延长了防砂有效期,施工成功率达到了100%。 相似文献
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通过粉体最紧密堆积粒径分布方程优化出矿渣和硅灰以4∶1混合为密实粉体组合(USG),并进行USG的减水率、胶砂强度、激发剂影响效应及掺USG的水泥浆体与外加剂的相容性试验.结果表明:USG与水泥和聚羧酸减水剂相容性优异;具有密实填充、增强效应;激发剂能显著提高USG水泥胶砂强度,其适宜掺量为2%~3%. 相似文献
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基层反射裂缝是沥青混凝土道面常出现的病害,合理的设置防反射裂缝夹层,是防止或延缓反射裂缝产生的重要措施。本文通过分析反射裂缝的成因及相应的防治措施,以北方某机场中跑道大修(一期)工程为例,着重对沥青砂土工布防反射裂缝夹层进行分析研究,从沥青砂配合比设计、土工布的选取、结合层的施工等方面进行介绍,为国内沥青跑道大修的基层处理提供经验借鉴。 相似文献
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介绍了玻璃纤维增强热固性树脂夹砂管生产成型、泄漏的形式及修复措施,以茂名100万吨,年乙烯7#循环水玻璃纤维增强热固性树脂夹砂管泄漏为例探讨了其修复措施及效果,对如何修复玻璃纤维增强热固性树脂夹砂管泄漏具有参考意义. 相似文献
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4 混凝土4 1 学习要点(1 )混凝土的组成及组成材料的作用 ,建筑工程中所使用的混凝土一般必须满足的四项基本要求。(2 )水泥标号的选择 ,理解水泥标号不能过低或过高的原因。(3)混凝土用砂的四项质量要求 ,其中包括 :混凝土用砂粒不能过粗或过细的原因 ,评定砂粗细的方法 ,细度模数的概念及如何用细度模数评定砂的粗细 ,砂的颗粒级配的概念以及用颗粒级配评定砂好坏的方法 ,碱—骨料反应及其产生的条件 ,坚固性的概念及检验方法 ,砂的饱和面干与饱和面干含水率的概念。(4)粗骨料的质量要求 ,当配制中等强度以下的混凝土时 ,应尽量采用最大… 相似文献
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该文以北京地铁6号线二期起点~物资学院站区间平交暗挖大断面施工为例,介绍了二重管无收缩双液WSS注浆技术在北京地铁6号线平交大断面区间隧道中的应用。工程实践证明,对采用矿山法施工、初期支护结构位于粉细砂层、细中砂层和砂卵石层中时,采用WSS工法进行注浆加固,能较好地改善开挖面土层性质,注浆加固效果十分明显,达到预期安全目标。 相似文献
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介绍了袋装砂井软土地基处理方法的施工过程,袋装砂井井深的检验方法,用冲水拔袋法可以有效的检验井深. 相似文献
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The concept of grit as described by Duckworth (Journal of personality and social psychology 92:1087, 2007) has captured the attention of educators and researchers alike. A measure of a student’s ability to effortfully persist in the face of struggle, grit is proposed to be an important characteristic required for students to succeed academically (Duckworth in Journal of personality and social psychology 92:1087, 2007). Some evidence suggests that grit has a positive relationship with a range of academic outcomes, and yet others argue that grit offers little in terms of predictive value for understanding academic outcomes. In addition, there is conflicting evidence about the presence of gender differences in grit, and very little research around the role of being the first member of the family to attend university in the development of grit. In order to address conflicting findings about the importance and correlates of grit, and to explore the role of engagement in the relationship between grit and academic outcomes, a cross sectional survey study was conducted. The current research measured grit, engagement and academic productivity among 395 Australian university students. Findings suggest that there is no difference in grit between genders, although this cannot be concluded with certainty due to a large imbalance of male to female participants. It also appeared that being the first in family to attend university was associated with an increased level of the grit factor ‘effort’. There was a positive relationship between grit, engagement and academic productivity. Further analysis revealed that engagement mediated the relationship between grit and productivity, suggesting that a person with higher grit is more likely to have higher engagement, and that engagement leads to greater academic productivity. These findings highlight the relevance of grit as a desirable student characteristic, and the importance of engagement in the grit-productivity relationship. 相似文献
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Despite the widespread enthusiasm towards grit, little attention has been paid to how stable grit remains over time and what contextual factors can predict longitudinal changes in grit. The present study investigated adolescent students’ grit and its change over one year. We employed nationally representative longitudinal data from a sample of Korean adolescent students (N = 2,590) and their parents (N = 2,590). Specifically, we evaluated the temporal stability of student grit, parent grit and educational expectations as determinants of student grit, and the relative importance of student grit in predicting academic achievement compared to academic self-concept. Results of autoregressive cross-lagged modeling revealed that grit was fairly stable over one year. In addition, parents’ grit and educational expectations for students’ educational attainment emerged as significant predictors of longitudinal changes in students’ grit. Finally, when students’ academic self-concept was controlled, students’ grit was not predictive of their academic achievement. Implications and areas of future research are presented and discussed. 相似文献
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Ariana Gonzalez Stokas 《Educational theory》2015,65(5):513-528
Recently, due in part to the research of Angela Duckworth, the cultivation of dispositions in education, grit in particular, has gained the attention of educational policymakers and the educational research community. While much of the research has focused on how to detect grit, there has been little discussion regarding how grit came to be valued as a noncognitive disposition and what its recent prominence might tell us about current social conditions. In this essay, Ariana Gonzalez Stokas attempts to illuminate grit as a concept that has undergone a number of conceptual transformations in American culture. She seeks to show how grit developed as a way to justify social and economic inequality and how this history is bound up in its conceptual structure. Through conducting a genealogical excavation, Stokas reveals the relationship of grit to a cluster of cultural events that occurred at the turn of the twentieth century in the confluence of boxing, cowboys, and Theodore Roosevelt, and aims to illuminate how grit has served as a tool for convincing society that achievement occurs through heroic individual effort despite inadequate social supports. This historical understanding of grit, Stokas concludes, may help us to recognize that the energy and resources currently spent on cultivating grit in children would be better spent on ameliorating the problems of social and economic inequality. 相似文献
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In recent years, grit has drawn increasing attention from both researchers and practitioners. As an important noncognitive indicator, grit has been used to understand individual success and performance in various fields. However, past empirical research has shown inconsistent findings on the relationship between grit and academic achievement. This study aims to review and synthesize past empirical findings on the relationship between grit and academic achievement. Forty‐four relevant articles involving a total of 60,133 participants met the inclusion criteria and were synthesized in this meta‐analysis. Our findings suggest that (a) overall grit level and its two facets (consistency of interest and perseverance of effort) are positively associated with academic achievement; (b) the association between grit and academic achievement is moderated by grade level; and (c) perseverance of effort shows the largest effect size on students’ academic achievement when compared with overall grit level and consistency of interest. 相似文献
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Kelly N. Clark Nicole B. Dorio Morgan A. Eldridge Christine K. Malecki Michelle K. Demaray 《Psychology in the schools》2020,57(2):204-221
Grit has been defined as passionate perseverance toward long-term challenging goals and it is associated with various positive outcomes for youth, including academic achievement. However, less is known about these associations for the two facets of grit (i.e., perseverance of effort, consistency of interest) and few studies have examined the link between grit and perceived social support. The present study examined the group-level demographic differences (i.e., gender, grade, socioeconomic status, and special education status) of grit in a high school sample (N = 1,077). In addition, direct associations between grit and perceived social support from multiple sources (i.e., teacher, classmate, parent) were examined, as well as a potential enhancing effect of social support as a moderator of the relation between grit and academic achievement. Results indicated positive associations among grit and its facets with social support from parents and classmates. Furthermore, the positive relation between grit and achievement was stronger for students reporting high social support from teachers, but not other sources (i.e., classmates, parents). Practical and theoretical implications for promoting student success are discussed. 相似文献
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Promoting an educated labor force is critical for emerging economies. Educational achievement, in turn, depends heavily on general cognitive abilities as well as non-cognitive skills, such as grit. Current research, however, has not examined how cognition and grit may explain the academic performance of students in an economically disadvantaged context. Thus, this study examines how IQ and grit contribute to academic achievement gains for students in poor areas of rural China. Drawing on data from 2931 students in rural China, we measure general cognitive ability, using the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) and Raven’s Standard Progressive Matrices (Raven IQ); non-cognitive ability, using the Short Grit Scale; and academic achievement, using a curricular-based mathematics exam. We find that IQ and grit each predict achievement gains for the average student. Grit is not positively associated with achievement gains among low-IQ students, however, suggesting that grit does not translate into academic achievement gains for students with delays in general cognitive ability. 相似文献
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Daniel Peterson 《Journal of Philosophy of Education》2015,49(4):571-589
Non‐cognitive dispositions have recently become psychological constructs of interest in the education, economics, philosophy, sociology, and psychology literature. In this article, I draw the distinction between property‐first and measurement‐first approaches to understanding the meaning of a particular non‐cognitive disposition theoretical term, ‘grit’, as well as the relationship between this term and its corresponding measurement procedure. I argue that, depending on which approach one takes, one is confronted with different norms for judging the success of any disposition‐measurement procedure pair, meaning that the difference in philosophical approaches may have practical import. I argue that the measurement‐first approach is the one educators and educational policy‐makers ought to adopt towards grit as it is less likely to lead to over‐valuing grit in situations where a gritty disposition may be harmful, better respects scientific virtues and values, and provides a clearer understanding of grit than the property‐first approach. 相似文献
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铝合金轴心受压构件需要引入系数ηas来考虑截面不对称性带来的不利影响.在大量数值分析的基础上,提出了系数ηas的计算公式,可以作为设计计算的依据.提出了广义的稳定计算系数的概念,用以在确定铝合金轴心受压构件的屈曲抵抗力时考虑系数ηas的影响,这样可与惯用设计方法相一致. 相似文献
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冷弯型钢工艺在铝型材生产中的应用 总被引：1，自引：0，他引：1
介绍了铝型材的孔型设计方法,通过采用组合孔型系统和固定圆弧中心变形,使生产的产品质量合格、尺寸准确.孔型具有设计简单,模具投入费用低等优点. 相似文献
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本文通过对ISO标准砂试验中的一些关键因素进行研究，根据有关实验和数据探讨标准砂净重对强度试验的相关影响。 相似文献