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网格计算环境下的数字化图书馆安全模型和访问控制安全策略研究* 总被引：1，自引：0，他引：1
在讨论网格安全性需求的基础上提出一种可伸缩、可扩展的访问控制安全策略与相应的安全模型,并提出一种灵活的访问控制安全策略,它支持网格计算环境固有的动态性、可伸缩性和可扩展性。相应的访问控制安全模型基于该策略进行设计,通过基于XML的查询请求/断言应答语言SAML和可扩展访问控制语言XACML来支持身份认证和访问控制。 相似文献
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在陕西省档案馆馆藏的10余万册资料里,有三部最早出版发行的、记述红军长征的珍贵史料.第一部:<红军长征记>(上、下册).第二部:<二万五千里长征>.第三部:<二万五千里长征记>. 相似文献
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Hae Yeon Lee Jeremy P. Jamieson Adriana S. Miu Robert A. Josephs David S. Yeager 《Child development》2019,90(6):e849-e867
Grades often decline during the high school transition, creating stress. The present research integrates the biopsychosocial model of challenge and threat with the implicit theories model to understand who shows maladaptive stress responses. A diary study measured declines in grades in the first few months of high school: salivary cortisol (N = 360 students, N = 3,045 observations) and daily stress appraisals (N = 499 students, N = 3,854 observations). Students who reported an entity theory of intelligence (i.e., the belief that intelligence is fixed) showed higher cortisol when grades were declining. Moreover, daily academic stressors showed a different lingering effect on the next day's cortisol for those with different implicit theories. Findings support a process model through which beliefs affect biological stress responses during difficult adolescent transitions. 相似文献
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Junzhen Ren Pengqing Bi Jianqi Zhang Jiao Liu Jingwen Wang Ye Xu Zhixiang Wei Shaoqing Zhang Jianhui Hou 《国家科学评论(英文版)》2021,8(8)
Developing photovoltaic materials with simple chemical structures and easy synthesis still remains a major challenge in the industrialization process of organic solar cells (OSCs). Herein, an ester substituted poly(thiophene vinylene) derivative, PTVT-T, was designed and synthesized in very few steps by adopting commercially available raw materials. The ester groups on the thiophene units enable PTVT-T to have a planar and stable conformation. Moreover, PTVT-T presents a wide absorption band and strong aggregation effect in solution, which are the key characteristics needed to realize high performance in non-fullerene-acceptor (NFA)-based OSCs. We then prepared OSCs by blending PTVT-T with three representative fullerene- and NF-based acceptors, PC71BM, IT-4F and BTP-eC9. It was found that PTVT-T can work well with all the acceptors, showing great potential to match new emerging NFAs. Particularly, a remarkable power conversion efficiency of 16.20% is achieved in a PTVT-T:BTP-eC9-based device, which is the highest value among the counterparts based on PTV derivatives. This work demonstrates that PTVT-T shows great potential for the future commercialization of OSCs. 相似文献
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既有研究表明面临资源短缺的中小企业能够通过资源拼凑实现创新，然而其并未揭示资源拼凑促进创新的作用过程和机制。基于组织学习理论的视角，本文构建了智力资本（人力资本、组织资本、社会资本）在资源拼凑到创新过程中的中介模型，并基于珠三角地区200家中小企业的数据进行了检验。研究结果表明智力资本部分中介了资源拼凑到创新的关系：资源拼凑在直接促进创新的同时，也间接通过提升企业的智力资本促进创新。在理论上，本研究揭示了资源拼凑对创新的作用过程和机理，弥补了已有研究的不足；在实践上，本研究为面临资源短缺的中小企业如何克服资源短缺，提升智力资本，进而推动创新提供了重要参考。 相似文献
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用研究成果质量、研究环境质量、受同行尊重程度三个评估项构建了我国高等医学院校科研能力内部评估体系,采用专家评定法及改进型层次分析法确定评估体系权重及运用模糊综合评价法构建评价模型,为高等医学院校优化资源配置、促进科技创新及长远发展提供了方向. 相似文献
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以项目教学为载体制订先进制造技术卓越工程师培养方案 总被引：11，自引：1，他引：10
针对应用型先进制造技术卓越工程师的培养标准和知识能力的具体要求,采用专业能力进阶培养和项目教学法的先进理念,构建出了核心专业知识模块、理论教学课程体系、实践教学体系、人文与职业素质培养体系、整个课程体系鱼骨图以及相应的学分要求等,然后对大学四年级实施的企业顶岗实习培养计划和毕业设计环节的具体要求进行了阐述,最后还对组织双师型结构教学团队的有效途径和方法进行了分析,以期通过实施本工作方案可以培养出具有大工程意识的先进制造技术高级工程技术人才。 相似文献