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61.
一类Riccati方程的通积分 总被引：1，自引：0，他引：1
冯录祥 《渭南师范学院学报》2007,22(2):9-11
给出Riccati方程y′=p（x）y^2＋q（x）y＋r（x）求积法的若干充分条件及其对应的通积分. 相似文献
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While there is a growing body of work that examines disciplinary identity development, unlike qualitative work in this area, quantitative research has not fully incorporated the importance of different contexts, nor has it uniquely focused on underrepresented groups (in this case, women in physics). This study examines how the constructs posited by prior work as important for physics identity, as well as an additional theorized construct, may interrelate and affect female students' physics identity differently depending on the context. Context in this study refers to two different experiential levels in college. The constructs examined include performance/competence, recognition, and interest, as well as sense of belonging. In particular, we used structural equation modeling to examine the effect that these constructs have on the physics identity of two groups of female physics undergraduates: first year students and senior year students. The results reveal that the relationship of the theorized constructs with physics identity vary between the two groups as well as compared to prior research with broad college student populations (not just physics majors). Unlike broad college student populations, for our sample of female physics undergraduates, interest did not have a direct effect on physics identity while sense of belonging was significant only for senior year students. These results exemplify the importance of examining context or different types of student experiences when studying disciplinary identity development rather than generalizing previous frameworks to all contexts. 相似文献
64.
研究了非线性Sobolev-Galpern型方程ut-uxxt=σ（ux）x的Cauchy问题.利用压缩映射原理和Minkowski不等式证明了其局部广义解的存在唯一性.进一步,通过能量估计方法和Gronwall不等式得到在一定条件下非线性Sobolev-Galpern型方程的Cauchy问题存在唯一的整体广义解. 相似文献
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Gary N. Marks 《Educational Research and Evaluation》2016,22(1-2):45-64
Multi-domain and longitudinal studies of student achievement routinely find moderate to strong correlations across achievement domains and even stronger within-domain correlations over time. The purpose of this study is to examine the sources of these patterns analysing student achievement in 5 domains across Years 3, 5 and 7. The analysis is of longitudinal population data of over 22,000 students and utilizes fixed-effects models to incorporate stable general and domain-specific latent factors. These latent factors correspond to a general cognitive-ability-like factor and specific aptitudes in particular, or types of, subject areas. The preferred model incorporates both general and domain-specific latent factors with stronger effects for the general factor, although the domain-specific factors are particularly strong for spelling and numeracy. When taking into account general and domain-specific latent factors, the effects of student’s socioeconomic status (SES) and school SES are trivial. 相似文献
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李龙杰 《顺德职业技术学院学报》2014,(1):38-41,52
打击假货,是政府维护社会经济秩序的责任,也是企业维护自身利益的行为。然而,打假应投入多少才合理、何时应改变打假的力度、怎么样的打假策略最佳等等问题直接关系到政府与企业的工作效益与经济收益。本文通过建立微分方程模型,以及通过打假者-制造者之间的博弈,找出达到纳什均衡的条件等等的方式,从而得出假货产生与增长的规律,同时为打假提出若干意见。 相似文献
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二阶中立型差分方程解的振动性(Ⅱ) 总被引：1，自引：0，他引：1
高英 《雁北师范学院学报》1998,(2)
该文对某类二阶非线性中立型差分方程解的振动性进行了讨论,改变了[8]中原有方程的条件,因而完善了此类二阶中立型差分方程解的振动性结果。 相似文献