共查询到20条相似文献，搜索用时 734 毫秒
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王欣 《扬州职业大学学报》2003,7(1):33-35
我国GBl77—85水泥标准已停止使用，并全面实施GB／T17671—99《水泥胶砂强度检验方法(ISO法)》及六大通用水泥新标准。为适应新标准，通过对新旧水泥标准的对比分析，针对不同点，提出提高水泥质量的途径。 相似文献
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由于再生骨料混凝土的强度和耐久性低于普通骨料混凝土,再生骨料的使用一直没有被广泛普及。为了提高再生粗骨料混凝土的物理性能,本文提出了利用高炉矿渣砂制造再生粗骨料混凝土。高炉矿渣砂的使用将能够有效地改善混凝土的耐久性和抗冻融损伤性能。在普通混凝土长期性能和耐久性能试验方法标准中的抗冻试验方法的基础上,使用液氮进行快速冻融试验,对经处理的低等级再生粗骨料和高炉矿渣砂混凝土的泌水性能、抗压强度和抗冻融性能进行了研究,结果表明,采用经处理的低等级再生粗骨料和用高炉矿渣砂替代50%或30%的破碎砂的混凝土有优良的泌水和抗冻融性能。 相似文献
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为研究机制砂混凝土的抗压强度和劈拉强度的变化规律,对低水胶比和20％矿渣掺量下配制C35的机制砂混凝土进行试验研究.试验数据表明:配置机制砂混凝土需要提高砂率,砂率一般宜大于38％;机制砂混凝土的早期强度较天然砂混凝土低,但后期增长较快;相对于天然沙,要更加重视对不同批次机制砂的质量检测;适当提高高效减水剂的掺量可以改善机制砂混凝土的工作性. 相似文献
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通过对红003井区稠油井的油藏特征分析,进行了室内防砂模拟实验研究,优选了防砂材料、防砂工具及管柱研究,优化了防砂施工参数,确定了以绕丝筛管挤压砾石充填为主导防砂方法,通过现场试验应用,防砂取得了良好的防砂效果。 相似文献
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沈玉兰老师执教的《砂和粘土》一课,诱发了我对本课教学结构的点滴思考。 《砂和粘土》最成功的地方是通过学生亲自动手、动眼、动口、动脑的活动,在孩子们头脑中留下了深刻印象,并具体地培养了观察、比较、实验、表达能力。教学思路十分清晰,但从启蒙教育的更高标准来要求,不足之处也在于认识活动不够充分。 一、形成概念操之过急 学生初步观察两种不同的东西后,回答:一盘是砂,一盘是土”,教师接着肯定是“砂和粘土”,继而板书课题。“粘”字从何而来?自 相似文献
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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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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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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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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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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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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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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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介绍了一种已实现工业应用的磨砂型材生产工艺。在前人研究的基础上 ,根据铝的性质 ,从碱液浓度、温度、络合、整平等方面进行试验 ,发展了砂面剂。介绍了砂面剂中部分物质的作用 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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Data were collected from 289 undergraduate college students at a minority‐serving institution to explore the impact of academic rational beliefs on grit and resilience. Findings from hierarchical regression analyses suggested that academic rational beliefs related to evaluation and work habits accounted for a significant amount of variance in grit. Work habits explained a significant portion of the variance in resilience. On the basis of these results, recommendations for future research and implications for college counselors are offered. 相似文献
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AbstractSoft skills such as grit, self-control, and self-confidence have been shown to predict outcomes in school and in life. As such, their valid and reliable measurement is of substantial interest in educational research and policy circles. However, the vast majority of this research originates in Western countries; relatively little is known regarding the measurement of soft skills in developing country contexts and whether similar types of instruments can provide evidence of these skills. This paper presents a novel means of assessing grit, self-control, and self-confidence in rural Tanzania: through the use of scenario-based self-report questionnaires. Survey instruments were administered in three regions in Tanzania to 961 Standard 2 pupils. We found that scenario-based items provided valid and, in most cases, reliable estimates of the three tested soft skills. When comparing self-reported soft skills and reading ability, we found that both grit and self-control were significant predictors of reading and mathematics performance. After controlling for sex, region, and age, grit was found to have a stronger association with reading performance than socioeconomic status. 相似文献