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Search Results: 1 - 10 of 77809 matches for " 黄欢 "
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一种双近邻表示的演化算法解决tsp

武汉理工大学学报 , 2006,
Abstract: ?用演化算法解决旅行商问题(tsp)时,传统的路径表示方法是非常不适合演化过程处理的。提出了一种双近邻表示法。这种能够将每个路径唯一表示的新的方法提高了演化算子的继承能力。为了提高收敛速度,演化算子中还使用了一种混合的局部搜索。大量的标准测试题的实验结果可以表明该文提出的算法能够全部达到或更优于现存最优解。
条形基础排架桥的结构形式及其抗冻性能

冰川冻土 , 1986,
Abstract: 钢筋混凝土条形基础排架桥,是在埋桩式排架木桥的基础上发展起来的一种结构轻薄、抗冻性能良好的农村道路桥梁。自1973年以来,农安县已建成140座,至今无一冻拔破坏。此种桥有较高的经济效益,每延米桥长混凝土工程量为2.5—3.2m3,每延米投资1200—1700元。
基于Moore-Penrose逆的加权距离函数研究
德才,,
控制与决策 , 2012,
Abstract: “距离”是科学研究与工程技术领域中使用非常广泛的一种度量.在分析各种距离优、缺点的基础上,根据马氏距离不受量纲影响,能描述和处理相关性数据的性能优势,利用加权Moore-Penrose(WMP)广义逆定义了WMP马氏距离,并通过奇异值分解及矩阵的谱分解理论构造其数学形式和计算方法.理论分析和仿真实验表明,所提出的方法不仅保持了马氏距离和MP马氏距离的优点,而且克服了它们的缺点,同时又具有更好的独特性能.
Fuzzy数空间上几种收敛结构的关系
毛青松,
福州大学学报(自然科学版) , 2004,
Abstract: 给出了模糊数空间上 3种收敛之间的关系 :limn→∞D∞(un,u) =0 limn→∞sendun =sendu un →Γu ,[un]0→dH[u]0 .并通过一反例说明条件 [un]0 →dH[u]0 是必要的
QFD和Kano模型的集成方法及应用
段黎明,
重庆大学学报 , 2008, DOI: 10.11835/j.issn.1000-582X.2008.05.010
Abstract: 针对质量功能配置(qualityfunctiondevelopment,QFD)应用过程中的难点,即如何准确而有效地理解用户需求,将Kano模型引入QFD,以Kano模型的分析结果作为QFD的输入.同时,在总结Matzler和Hinterhuber集成方法的基础上,针对其不足,利用更广泛的评分等级更清楚地表明用户需求和工程特性间的强相关与弱相关的区别,用权重统计测试法来处理当2个用户需求的权重很相近时的情况,在此基础上对原集成法进行改进,并实际应用于某一机电产品,证明了此方法的有效性.
双重脱嵌与新生代农民工的阶级形成

社会学研究 , 2014,
Abstract: 本文将新生代农民工的留守经历放在嵌入性视角下进行考察,发现新生代农民工呈现同时脱嵌于乡村与城市社会的特点,且“双重脱嵌”之间具有内在的逻辑联系:留守经历导致新生代工人脱嵌于乡村社会,而这一主体性伴随其进入城市,导致其脱嵌于城市的劳动现场。双重脱嵌下的新生代农民工处于持续不断的流动与漂泊状态,从而使得自为意义上的阶级形成面临重重困境。在此基础上,本文与“工厂政体”和“未完成的无产阶级化”两种工人阶级形成的解释逻辑展开了对话,指出工人阶级的形成还需要考虑具体历史情境下的重新嵌入问题。?
基于广义马氏距离的缺损数据补值算法
,德才?
计算机科学 , 2011,
Abstract: 在数据收集过程中数据缺损是不可避免的。如何还原这些缺损数据,成为数据挖掘研究的热点问题之一。与许多现有算法一样,基于马氏距离的缺损数据补值算法充分利用了实际数据之间的相关性,具有较好的补值效果,但它要求数据的相关性协方差矩阵可逆,使其应用范围受到了极大的限制。在改进传统主成分分析方法的基础上,利用矩阵的奇异值分解理论和moorspcnrosc广义逆性质,提出了广义马氏距离的概念,并运用于sofm神经网络,结合信息嫡理论设计了基于广义马氏距离的缺损数据补值算法—gs算法。理论分析和数值仿真结果表明,广义马氏距离完全继承了马氏距离在处理相关性数据上的性能优势,新算法不仅在补值的精确度和稳定性上有很好的效果,而且适用于任意数据集合。
跑台运动训练对脑缺血大鼠轴突导向因子Netrin-4及其受体DCC蛋白表达的影响
,刘楠
- , 2015,
Abstract: 目的观察跑台运动训练对脑缺血大鼠脑组织中轴突导向因子Netrin-4及其受体结直肠癌缺失(DCC)蛋白表达的影响,旨在探讨运动训练促进脑缺血后神经功能恢复的相关机制。 方法取成年雄性SD大鼠63只,按随机数字表法分为假手术组(n=9)、模型组(n=27)和运动组(n=27)。模型组和运动组大鼠采用改良的Longa线栓法制备大脑中动脉闭塞(MCAO)脑缺血模型,假手术组大鼠手术方法同模型组和运动组,但是不插入线栓。运动组于造模成功后24h采用跑台训练器进行运动训练,其余2组则不进行运动训练。采用修正的神经行为学评分方法(mNSS)评价模型组和运动组大鼠造模后第3、7、14天的神经功能,并断头取脑,采用Western blot法以及免疫荧光法检测脑缺血区组织中Netrin-4、DCC蛋白的表达情况。 结果造模后第3、7、14天,运动组和模型组的mNSS评分与假手术组比较,差异均有统计学意义(P<0.01);造模后第7、14天,运动组的mNSS评分分别为(6.89±1.27)分和(5.22±1.09)分,低于模型组同时间点,差异均有统计学意义(P<0.05);造模后第7、14天,运动组的Netrin-4、DCC蛋白表达均较模型组增强(P<0.05);造模后第14天,经免疫荧光法检测发现,Netrin-4主要在脑缺血区的血管和星形胶质细胞中表达,而DCC蛋白主要在脑缺血区的神经元轴突和星形胶质细胞中表达。 结论跑台运动训练可促进脑缺血大鼠神经功能恢复,其机制可能与上调脑缺血区组织中Netrin-4、DCC蛋白的表达,进而增强了神经、血管的再生和重建有关。
Objective To observe the effects of treadmill training on the expression of axonal guidance factor Netrin-4 and its receptor deleted in colorectal cancer (DCC) protein in the brains of rats with cerebral ischemia. Also to explore how training promotes the recovery of neurological function after cerebral ischemia. Methods Sixty-three adult, male Sprague-Dawley rats were randomly divided into a sham group (n=9), a model group (n=27) and an exercise group (n=27). A modified version of Longa′s method was used to establish an animal model of cerebral ischemia by occluding the right middle cerebral artery (MCAO) in the rats of the model and exercise groups while the rats of the sham group were subjected to the same surgical procedure except that no thread was inserted. The rats of the exercise group were given treadmill training beginning 24 h after the modeling, while those of the other two groups were left on the treadmill without training. The rats′ neurological functioning was tested by assigning modified neurological severity scores (mNSS) on the 3rd, 7th and 14th day after modeling. Then the ischemic brain tissue was dissected to detect the expression of Netrin-4 and DCC protein using western blotting and immunofluorescent staining and analysis. ResultsOn the 3rd, 7th and 14th day after modeling, the model and exercise groups had significant differences in their average mNSS scores when compared to the sham group. The average mNSS scores of the exercise group on the 7th and the 14th day were significantly lower than those of the model group at the same time point. The average expression level of Netrin-4 and DCC protein in the exercise group was significantly higher in than the model group on the 7th and 14 th days. Immunofluorescent staining showed that Netrin-4 was mainly observed in the blood vessels and astrocytes in the ischemic brain area. DCC protein was
课程干预与不平等社会结构的扭转:皖东村校的尝试
Course Intervention and the Reverse of Inequality Social Structure: The Practice Based on a Village School in East Anhui


- , 2018,
Abstract: 本文试图以批判教育社会学中扭转不平等社会结构的理论框架为指导,发展出一种针对当前中国留守儿童的可行性课程干预实践模式。呼应文化再生产的理论,考察留守儿童的学习过程发现,其学业表现失败一方面是压制性体制下资源缺乏的结果,另一方面也和课堂学习对于底层文化和经验的忽视有关。基于文化的生产性与创造性原则,尊重底层学生的文化和经验、将课堂外的社会情境导入课堂,有可能打造出转折的图景。这一做法,首先可以通过再情境化学生的文化经验激活学生的批判意识和批判思考能力,其次可以突显留守儿童在社会和文化情境中的相对优势,进而促进其学习认同与学业成就。针对安徽新镇留守村校的以研究性学习方式呈现的课程干预试验为我们提供了引入课堂外情境的可能做法和具体效应。结合弗雷勒“提问式”教育的方法,我们探讨了“扩展的文化再生产干预路径”所具有的扭转社会结构的意义。
Based on the theory of criticism education, this article attempts to develop a feasibility guide to intervention the situation of the left-behind children through the course. Responding to the culture reproduction theory, the study of left-be- hind children reveal that their failure academic performance is the result of the lack of resources under the repressive system on the one hand , and on the other hand the result of the neglect of the underlying culture and experience inside classroom learning. Based on the productive and creative principle of the culture, respecting the students‘ underlying culture and ex- perience , and bringing the social situations from outside to inside the classroom, could bring us the possibility of change. This approach, firstly through recontextualized student's cultural experience, could activate the students' critical awareness and critical thinking skills, and secondly could highlight the comparative advantage of left-behind children in the social and cultural situation, and promote there learning motivation and academic achievement. Based on the practice of a village school in East Anhui, authors discussed the feasible approach and the role of bringing the community knowledge into the classroom. Combined with Paulo Freire’ s “ problem- posing education冶 method, authors also discussed the quality and characteristics of the “Anti-Cultural reproduction intervention paths冶 in the reversing of the inequality social structure.
选择性扩散和选择性吸附手性拆分膜及其应用
,
功能高分子学报 , 2002,
Abstract: 根据选择性分离机制的不同,介绍了选择性扩散和选择性吸附膜的手性折分机理及在手性化合物拆分中的应用,比较了两类膜在材料、制备方法、膜结构、膜性能、操作条件等方面的特点与差别。
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