您选择的条件: 2017-10-13
  • 基于TDTR方法的碳化硅低温导热性能实验研究

    分类: 动力与电气工程 >> 工程热物理学 提交时间: 2017-10-13 合作期刊: 《工程热物理学报》

    摘要: 低温条件下碳化硅等半导体材料热导率的实验研究极少,数据匮乏,无法满足理论模型的优化需求。现有实验测量以接触式的稳态法导热系数测量为主,实验误差大,且低温测量成本过高。本文通过常规飞秒激光抽运探测热反射法与低温系统的有机结合,完成了4~300 K低温条件下单晶碳化硅热导率的测试及其随温度的变化规律,研究表明单晶碳化硅热导率在100 K左右存在极大值,温度低于100 K时其热导率与温度呈正相关,温度高于100 K时其热导率与温度呈负相关。极值点的位置与理论值的偏差可能是由于样品电子浓度、缺陷分布等因素影响。

  • 轴流压气机等离子体流动控制

    分类: 动力与电气工程 >> 工程热物理学 提交时间: 2017-10-13 合作期刊: 《工程热物理学报》

    摘要: 作者在国际上较早开展了轴流压气机等离子体流动控制研究工作,经过近十年的研究积累,对轴流压气机等离子体流动控制建立了较为深刻的认识。本文首先简要展示了轴流压气机等离子体流动控制的部分研究进展:以压气机叶栅为研究对象,分析了等离子体激励对叶顶泄漏流抑制的规律和机制;通过数值仿真和实验,研究了等离子体激励对高负荷轴流压气机失速的流动控制规律和机制;以高速压气机叶栅为研究对象,探索了吸力面和端壁等离子体激励对高速压气机三维角区分离的流动控制规律;然后介绍了等离子体激励式压气机的概念;最后给出了对未来研究工作的展望。

  • Chinese Color Nest Project (CCNP)i: Growing Up in China

    分类: 心理学 >> 实验心理学 提交时间: 2017-10-13

    摘要: Abstract: To face the challenges of keeping healthy in increasing population sizes of both ageing and developing people in China, a fundamental request from the public health is the development of lifespan normative trajectories of brain and behavior. This paper introduces the Chinese Color Nest Project (CCNP 2013–2022), a large-scale tenyear program of modeling brain and behavioral trajectories for human lifespan (6–85 years old). We plan to gradually collect the behavioral and brain imaging data at ages across the lifespan on nationwide and depict the normal trajectory of Chinese brain development across the lifespan, based on the accelerated longitudinal design in the coming next 10 years starting at 2013. Various psychiatric disorders have been demonstrated highly relevant to abnormal events during the neurodevelopment regarding their onset ages of first episodes. Therefore, delineation of normative growth curves of brain and cognition in typically developing children is extremely useful for monitoring, early detecting and intervention of various neurodevelopmental disorders. In this paper, we detailed the developing part of CCNP, devCCNP. It tracked 192 healthy children and adolescents (6–18 years old) in Beibei district of Chongqing for the first 5 years of the full CCNP cohort (2013–2017). To demonstrate the feasibility of implementing the longterm follow-up of CCNP, we here comprehensively document devCCNP in terms of its experimental design, sample strategies, data acquisition and storage as well as some preliminary results and data sharing roadmap for future. Specifically, we first describe the accelerated longitudinal sampling design as well as its exact ratio of sample dropping off during the data collection. Second, we present several initial findings such as canonical growth curves of cortical surface areas of a set of well-established large-scale functional networks of the human brain. Finally, together with records generated by many psychological and behavioral tests, we will provide an individual growing-up report for each family participating the program, initiating the potential guidance on the individual academic and social development. The resources introduced in the current work can provide first-hand data for a series of coming Chinese brain development studies, such as Chinese Standard MRI Brain Templates, Normative Growth Curves of Chinese Brain and Cognition as well as Mapping of Language Areas in Chinese Developing Brain. These would not only offer normative references of the atypical brain and cognition development for Chinese population but also serve as a strong force on accelerating the pace of integrating Chinese brain development into the national brain program or Chinese Brain Project.