一种改进的遥感热惯量模型初探

本文改进了遥感热惯量模型 ,考虑到植被因素的影响 ,在植被覆盖区 ,使用双层模型中的土壤热能量平衡方程 ,同时在热传导方程的边界条件中引进显热通量和潜热通量 ,使热惯量模型的应用范围从裸土扩展到植被覆盖区 .通过顺义地区的MODIS影像数据和同步野外测量数据对此模型进行验证 ,所获得的热惯量值与实测热惯量值进行比较 ,结果表明改进模型的实用性和可行性 .     

中尺度数值模式MM4在暴雨和强对流研究中的应用

在VAX-8350计算机上。建立了中尺度数值模拟系统(MM4).该系统包括资料处理、初始化、数值预报、诊断分析及绘图等.利用这个模拟系统,对暴雨和强对流天气进行了试验研究,取得了有益的结果:(1)凝结潜热的释放会导致中尺度天气系统发生发展,有利于产生暴雨.(2)低层水汽含量的多少,不仅直接影响凝结量,更重要是会影响大气静力稳定度,从而影响对流发展、潜热释放和雨量.(3)在适当的大尺度流场形势下,黄山、天目山地区会产生中尺度辐合流场,它使低层的水汽和热量辐合加强,潜热反馈作用显著增大,有利于中尺度系统发展和雨量增大.     

THERMODYNAMICS OF MELTING FOR METALS

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An integrative perspective of validating a simplified Chinese version behavioral regulation in exercise questionnaire-2

The study aims to examine psychometric property, measurement invariance, and latent mean difference of a Chinese version instrument of the Behavioral Regulation in Exercise Questionnaire ?2 (C-BREQ-2), which originally includes five constructs. The study also examined the relationship between C-BREQ-2and participants’ weekly moderate to vigorous physical activity (MVPA). Participants were middle and high school students recruited from Shanghai, China. The final sample (N = 437, 49% for boys) was randomly split into two subsamples, where the first subsample (N = 208) was used for exploratory factor analysis (EFA) and the second subsample (N = 229) for confirmatory factor analysis (CFA). Measurement invariance and latent mean difference across gender was examined. Structural equation modeling (SEM) was utilized to explore how different motivation types relate to adolescents’ weekly MVPA. Results showed that the revised 14-item, three-factor model is invariant at both configural, full metric, and full scalar levels across genders. The following latent mean comparison revealed that boys perceived higher introjected regulation than girls. Finally, only introjected regulation significantly and positively related to adolescents’ MVPA.     

负性生活事件潜在类别分析在大学生自杀风险筛查中的应用

This research collected 9295 university students’ stressful life events (SLEs) and suicide attempts within a year to conduct a latent class analysis and logical regression to explore the latent class and its correlation with the risk of suicide. The results showed that samples could be grouped in “less major SLEs”, “SLEs related to mental disorders” and “SLEs related to family atmosphere”, and students who experienced SLEs related to mental disorders and family atmosphere had higher risks of suicide, with those experiencing SLEs related to mental disorders to have the highest risks of suicide     

Improved Query Matching Using kd-Trees: A Latent Semantic Indexing Enhancement

Efficient information searching and retrieval methods are needed to navigate the ever increasing volumes of digital information. Traditional lexical information retrieval methods can be inefficient and often return inaccurate results. To overcome problems such as polysemy and synonymy, concept-based retrieval methods have been developed. One such method is Latent Semantic Indexing (LSI), a vector-space model, which uses the singular value decomposition (SVD) of a term-by-document matrix to represent terms and documents in k-dimensional space. As with other vector-space models, LSI is an attempt to exploit the underlying semantic structure of word usage in documents. During the query matching phase of LSI, a user's query is first projected into the term-document space, and then compared to all terms and documents represented in the vector space. Using some similarity measure, the nearest (most relevant) terms and documents are identified and returned to the user. The current LSI query matching method requires that the similarity measure be computed between the query and every term and document in the vector space. In this paper, the kd-tree searching algorithm is used within a recent LSI implementation to reduce the time and computational complexity of query matching. The kd-tree data structure stores the term and document vectors in such a way that only those terms and documents that are most likely to qualify as nearest neighbors to the query will be examined and retrieved.     

他们为何不上大学?——显在需求与潜在需求的决定要因

1976年以后,高中毕业生的大学升学率持续徘徊在50%前后。但是,先行研究并未说明学生们为什么不上大学,尽管他们能够很容易地进入大学。本文将探讨50%升学率背后所潜伏着的经济因素的影响程度。分析显示,选择直接就业的人主要是因为大学的高额学费,而选择升入专门学校的人主要是因为大学的高额学费和入学考试的低录取率。这一结果表明,如果考虑潜在需求的话,高等教育的实际需求要高于升学率所显示的程度。     

U12—14阶段动作发展特征及武术运动技能案例教学分析

摘要：为了更好的理解新课标、科学合理地发挥体育与健康教科书的指导作用,本文基于人类发展科学和动作科学理论及实践,运用文献资料法梳理U12——14阶段健康个体的发展特征、采用案例教学法针对武术运动项目（健身长拳、健身南拳、健身短棍）进行案例教学。综述文献概括发展特征,即,动作发展特征为基本动作技术向专门动作技术过渡,生长发展特征为男生开始突增且功能不协调、女生持续稳定且功能稳定,认知发展特征为大脑额叶仍在发展,情绪发展特征为情境性启动明显。案例教学得出发展视角下武术运动项目技能学习相关因素涉及动作约束因素、发展过程、劲力以及生物发展轨迹等特征。基于发展特征分析武术运动项目案例教学得出相关启示,即为了更科学合理的教学,体育教师应该拓展（动作）发展科学的相关知识体系。研究结果将为一线体育教学实践提供间接参考。     

基于Credal网络的企业科技竞争力评价模型

通过分析现存企业科技竞争力评价方法的局限性,提出利用带隐变量的Credal网络对企业科技竞争力进行评价的方法,以反映企业科技竞争力系统中的不确定性及复杂性,并能提供对企业科技竞争力的预测和诊断.建立了企业科技竞争力评价的通用Credal网络模型,并结合算例,采用枚举法阐述了具体推理过程,结果表明该方法是有效的.     

人性的趋恶本源性与制约引导性失衡成因初探

人性是人具有的对其思维活动及行为有决定性影响的特有属性,它包括趋恶本源性与制约引导性两方面。人性在二者不断的冲突与斗争之下,于善恶间摇摆不定,这种不协调的状态可称之为人性的失衡,这正是暴力性犯罪产生的根源。在一些外在客观因素作用下,人性趋恶本源性和制约引导性的冲突和斗争所形成的隐性失衡,犹如火山爆发般猝然地显性化,并直接影响人的行为,甚而使之趋于极端化时,因此将这个过程称之为隐性失衡的显性化,将这些造成影响的客观因素称之为外刺激,而暴力性犯罪正是人性的趋恶本源性与制约引导性不断冲突和斗争所导致的人性失衡在非良性外刺激作用下由隐性转为显性的结果。