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不良导体热导率的阶跃函数式加热法测量研究
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作者 詹士昌 《科技通报》 2000年第4期283-286,共4页
在获得有限平板阶跃函数式加热瞬态温度分布近似解的基础上 ,设计了一个不良导体热导率阶跃函数式加热动态测量装置 .该装置简单、实用 ,测量结果精确 。
关键词 阶跃函数加热 热导率 测量 不良导体
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地面热源强迫对青藏高原低涡作用的动力学分析 被引量:30
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作者 李国平 刘红武 《热带气象学报》 CSCD 北大核心 2006年第6期632-637,共6页
将一类暖性青藏高原低涡考虑为受加热和摩擦强迫作用并满足热成风平衡的轴对称涡旋系统,给定符合高原地面加热特点的加热分布函数,通过求解简化后的柱坐标系中的涡旋模式,得到了低涡对应的流函数、水平流场、水平散度场和垂直运动场的... 将一类暖性青藏高原低涡考虑为受加热和摩擦强迫作用并满足热成风平衡的轴对称涡旋系统,给定符合高原地面加热特点的加热分布函数,通过求解简化后的柱坐标系中的涡旋模式,得到了低涡对应的流函数、水平流场、水平散度场和垂直运动场的解析解,分析了地面热源对高原低涡流场结构的作用,给出了高原低涡眼壁内、外侧以及不同高度上的水平流场、水平散度场和垂直流场的结构特征,对影响低涡生成的主要因子进行了讨论。研究结果揭示了地面热源强迫对高原低涡的形成及结构特征的重要作用。 展开更多
关键词 低涡 高原 地面热源 加热函数 流场 结构
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Dropwise Condensation on a Rotating Condenser in Relation to Heat Transfer Intensification
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作者 M.K. El-Adawi T.H. Felemban 《Journal of Environmental Science and Engineering》 2010年第6期50-54,共5页
A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of swe... A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of sweeping the surface by departing droplets. The appearance of droplets with smaller radii will be predominant. These small droplets offer small thermal resistances, thus enhancing heat transfer through the condenser surface. It is found also that the maximum radius is a function of the distance from the axis of the rotating condenser. Thus the value of the maximum radius under rotation is not unique. This in turn makes the heat flux through the condenser surface not to be uniform. 展开更多
关键词 Dropwise condensation dropwise rotating condenser heat transfer
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Heating graphene to incandescence and the measurement of its work function by the thermionic emission method 被引量:6
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作者 Feng Zhu 《Nano Research》 SCIE EI CAS CSCD 2014年第4期553-560,共8页
The work function (WF) of graphene is an essential parameter in graphene electronics. We have derived the WF of graphene by the thermionic emission method. Chemical vapor deposition (CVD)-grown single-layered poly... The work function (WF) of graphene is an essential parameter in graphene electronics. We have derived the WF of graphene by the thermionic emission method. Chemical vapor deposition (CVD)-grown single-layered polycrystalline graphene on copper foil is transferred to a cross-stacked carbon nanotube (CNT) film drawn from a super-aligned multiwalled CNT array. By decreasing the pore size of the CNT film, the as-prepared CNT-graphene film (CGF) can be Joule heated to a temperature as high as 1,800 K in vacuum without obvious destruction in the graphene structure. By studying the thermionic emission, we derive the WF of graphene, ranging from 4.7 to 4.8 eV with the average value being 4.74 eV. Because the substrate influence can be minimized by virtue of the porous nature of the CNT film and the influence of adsorbents can be excluded due to the high temperature during the thermionic emission, the measured WF of graphene can be regarded as intrinsic. 展开更多
关键词 GRAPHENE carbon nanotube thermionic emission work function
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