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21.
在轻骨料混凝土中掺入钢纤维,配制钢纤维轻骨料混凝土。采用四因素、三水平的正交试验设计方法,研究了钢纤维掺量、粗骨料类型和粉煤灰替代率三种不同试验因素对轻骨料混凝土抗压强度、劈裂抗拉强度和抗冲击性能的影响。研究结果表明:粉煤灰替代率是影响轻骨料混凝土抗压强度的主要因素;粉煤灰替代率和钢纤维掺量是影响轻骨料混凝土劈裂抗拉强度的主要因素;钢纤维掺量变化、粗骨料类型和粉煤灰替代率三种因素对轻骨料混凝土抗初裂冲击次数影响不显著;钢纤维掺量变化是影响轻骨料混凝土抗终裂冲击次数的主要因素。  相似文献   
22.
川南富集区龙马溪组页岩气储层孔隙结构分类   总被引:9,自引:0,他引:9       下载免费PDF全文
运用压汞法测定川南龙马溪组页岩气储层孔隙特征,结合有机碳含量(TOC)、矿物成分进行多元回归分析,探讨孔隙主要影响因素,并对孔隙进行分类.结果表明,孔隙度平均为4.71%,发育程度中等;储集空间由超大孔、大孔、中孔、小孔和微孔组成;中孔、小孔和微孔为主要孔径,6~120 nm的孔隙占有重要比例;TOC和脆性矿物对孔隙形成有积极意义,且TOC影响最显著;黏土矿物相反,且其影响程度远小于TOC和脆性矿物含量.基于退汞曲线-TOC成因,将龙马溪组孔隙结构划分为3种类型:Ⅰ型(退汞曲线上凸型,高TOC),Ⅱ型(退汞曲线先凸后凹型,低TOC)和Ⅲ型(退汞曲线凹型,中TOC),其中具有Ⅰ型孔隙结构的页岩气储层为最有利储层.  相似文献   
23.
为了评价"五水共治"综合规划实施后水资源承载力变化情况,以临海市为研究对象,选取了17项评价指标构建水资源承载力评价指标体系,采用主成分分析法对评价指标进行降维处理,建立水资源承载力变化驱动因子的多元线性回归模型,提取水资源自然支持力、社会生活水平和经济发展水平3个子系统的主成分,并用熵值法对子系统赋权,计算水资源承载力综合得分,并进行分析评价。结果表明:"五水共治"综合规划实施后,临海市水资源承载力有明显提高,治污、开源、节流是提升水资源承载力的主要因素。  相似文献   
24.
针对萧绍宁平原河网水源补给不足、水体流动性较差特点,以浙东引水工程和区域内引排工程为基础,拟定了萧绍宁平原引配水格局,分析了浙东引水工程改善萧绍宁平原河网水环境的效果,为萧绍宁平原实施"五水共治"之治污水提供了技术支撑。  相似文献   
25.
Understanding the relation between large-scale and small-scale functionality is an acute problem in large systems. This paper presents possible structures that capture those relations. Here “structure” means a functor on a category, in this case the category of “combinatorial systems” that model manufacturing systems and supply networks. The details of the dynamics of these systems are frequently the domain of specialists and are ill understood outside such areas. Clustering activities in subsystems introduces covers as scales of analysis. This allows the development of sheaves of schedules and their properties which are analyzed by an adaptation of ?ech cohomology. These are applied in supply networks to characterize the fragmentation of these networks and to characterize the conditions for local changes in schedules to extend to the whole system. The intent of this paper is to see sheaves and their cohomology as analytical probes that can enhance our understanding of large-scale systems.  相似文献   
26.
Factor-analytic research is common in the study of constructs and measures in psychological assessment. Latent factors can represent traits as continuous underlying dimensions or as discrete categories. When examining the distributions of estimated scores on latent factors, one would expect unimodal distributions for dimensional data and bimodal or multimodal distributions for categorical data. Unfortunately, identifying modes is subjective, and the operationalization of counting local maxima has not performed very well. Rather than locating and counting modes, the authors propose performing parallel analyses of categorical and dimensional comparison data and calculating an index of the relative fit of these competing structural models. In an extensive Monte Carlo study, the authors replicated prior results for mode counting and found that trimming distributions' tails helped. However, parallel analyses of comparison data achieved much greater accuracy, improved base rate estimation, and afforded consistency checks with other taxometric procedures. Two additional studies apply this approach to empirical data either known to be categorical or presumed to be dimensional. Each study supports this new method for factor-analytic research on the latent structure of constructs and measures in psychological assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
27.
In this brief rejoinder, we respond to Farmer, Monaghan, Misyak, and Christiansen (2011). We argue that the data still do not support the claim that reading time is affected by the phonological typicality of a word for its part of speech. We also question Farmer et al.'s claim that interleaving syntactic structures in an experiment modifies grammatically based syntactic expectations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
28.
The theory–theory account of conceptual development posits that children's concepts are integrated into theories. Concept-learning studies have documented the central role that theories play in children's learning of experimenter-defined categories but have yet to extensively examine complex, real-world concepts, such as health. The present study examined whether providing young children with coherent and causally related information in a theory-based lesson would facilitate their learning about the concept of health. This study used a pretest/lesson/posttest design, plus a 5-month follow-up. Children were randomly assigned to 1 of 3 conditions: theory (i.e., 20 children received a theory-based lesson), nontheory (i.e., 20 children received a nontheory-based lesson), and control (i.e., 20 children received no lesson). Overall, the results showed that children in the theory condition had a more accurate conception of health than children in the nontheory and control conditions, suggesting the importance of theories in children's learning of complex, real-world concepts. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
29.
A number of recent studies have used Meehl’s (1995) taxometric method to determine empirically whether one should model assessment-related constructs as categories or dimensions. The taxometric method includes multiple data-analytic procedures designed to check the consistency of results. The goal is to differentiate between strong evidence of categorical structure, strong evidence of dimensional structure, and ambiguous evidence that suggests withholding judgment. Many taxometric consistency tests have been proposed, but their use has not been operationalized and studied rigorously. What tests should be performed, how should results be combined, and what thresholds should be applied? We present an approach to consistency testing that builds on prior work demonstrating that parallel analyses of categorical and dimensional comparison data provide an accurate index of the relative fit of competing structural models. Using a large simulation study spanning a wide range of data conditions, we examine many critical elements of this approach. The results provide empirical support for what marks the first rigorous operationalization of consistency testing. We discuss and empirically illustrate guidelines for implementing this approach and suggest avenues for future research to extend the practice of consistency testing to other techniques for modeling latent variables in the realm of psychological assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
30.
Part 1. The core of the concept analysis method is a dictionary of 43,000 words to each of which is assigned up to 5 of 168 concepts. Computer programs read each word of a text and produce a concept frequency profile of the text.Part 2. Comparisons of concept profiles ofTub andGulliver and Swift's own contemporary texts, as well as a composite text of 18th century writers, reveal thatGulliver is conceptually different fromTub and its coevals. The fourth book ofGulliver (Houyhnhnms) is significantly different from the first three books. The last two books ofGulliver (Laputa and Houyhnhnms) are more likeTub than are the first two books (Lilliput and Brobdingnag).Part 3. The concepts and words supporting these distinctions suggest two strands in Swift's thinking: the first, pessimism about the human condition; the second, interest in the quotidian world. Finally, such issues as disambiguation of homonyms, scoring of phrases, and the role of syntax are considered.Julius Laffal is Associate Clinical Professor of Psychiatry (in Psychology) at Yale University. He was Director of Research and Psychological Services at Connecticut Valley Hospital from 1969 to 1985. He has been Adjunct Professor of Psychology at Wesleyan University, and Professor in Residence, Psychology, at University of Connecticut. He is the author ofNormal and Pathological Language (1965) andA Concept Dictionary of English with Computer Programs for Content Analysis (1990).  相似文献   
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