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heat transport in coupled inhomogeneous chains

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Chinese Physics B 2011年第6期20卷 125-130页

作者：胡涛白萌胡柯唐翌 Department of Physics Xiangtan University

We first investigate the heat transport in a network model consisting of two coupled dimerized chains. Results indicate that the thermal resistance of each chain increases with the decrease of the mass ratio γ. of the two types of atoms. Then, we find, when a light impurity or a heavy one is added in the two coupled homogeneous chains and coupled with a particle of another chain, the interface thermal resistances Rint and Rint present different dependences on the mass ratio γ Finally, a persistent circulation of energy current is observed in coupled inhomogeneous chains with two pairs of interchain coupling.

关键词： heat transport thermal resistance

heat transport of Electron-Doped Cobaltates

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Communications in Theoretical Physics 2006年第1X期46卷 171-174页

作者： LIU Bin LIANG Ying FENG Shi-Ping CHEN Wei-Yeu Department of Physics Beijing Normal University Beijing 100875 China Department of Physics Tamkang University Tamsui 25137 Taiwan China

Within the t-J model, the heat transport of electron-doped cobaltates is studied based on the fermionspin theory. It is shown that the temperature-dependent thermal conductivity is characterized by the low-temperature peak located at a finite temperature. The thermal conductivity increases monotonously with increasing temperature at low-temperatures T 〈 0.1 J, and then decreases with increasing temperature for higher temperatures T 〉 0.1 J, in qualitative agreement with experimental result observed from NaxCoO2.

关键词： heat transport electron-doped cobaltates fermion-spin theory

Low-temperature heat transport of spin-gapped quantum magnets

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Science China(Physics,Mechanics & Astronomy) 2016年第11期59卷 1-16页

作者： Xia Zhao ZhiYing Zhao XuGuang Liu XueFeng Sun School of Physical Sciences University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of ChinaHefei 230026China Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of SciencesHefei 230026China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

This article reviews low-temperature heat transport studies of spin-gapped quantum magnets in the last few decades. Quantum magnets with small spins and low dimensionality exhibit a variety of novel phenomena. Among them, some systems are characteristic of having quantum-mechanism spin gap in their magnetic excitation spectra, including spin-Peierls systems, S=1Haldane chains, S= 1/2 spin ladders, and spin dimmers. In some particular spin-gapped systems, the XY-type antiferromagnetic state induced by magnetic field that closes the spin gap can be described as a magnon Bose-Einstein condensation(BEC). heat transport is effective in probing the magnetic excitations and magnetic phase transitions, and has been extensively studied for the spin-gapped systems. A large and ballistic spin thermal conductivity was observed in the two-leg Heisenberg S=1/2 ladder compounds. The characteristic of magnetic thermal transport of the Haldane chain systems is quite controversial on both the theoretical and experimental results. For the spin-Peierls system, the spin excitations can also act as heat carriers. In spin-dimer compounds, the magnetic excitations mainly play a role of scattering phonons. The magnetic excitations in the magnon BEC systems displayed dual roles, carrying heat or scattering phonons, in different materials.

关键词： heat transport quantum magnets spin gap

Estimating the effect of shallow groundwater on diurnal heat transport in a vadose zone

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Frontiers of Earth Science 2016年第3期10卷 513-526页

作者： Jianmei JIANG Lin ZHAO Zhe ZHAI School of Chemical Engineering Tianjin University Tianjin 300072 China School of Environment Science and Engineering Tianjin University Tianjin 300072 China

The influence of shallow groundwater on the diurnal heat transport of the soil profile was analyzed using a soil sensor automatic monitoring system that continu- ously measures temperature and water content of soil profiles to simulate heat transport based on the Philip and de Vries （PDV） model. Three experiments were conducted to measure soil properties at depths of 5 cm, 10 cm, 20 cm, and 30 cm when groundwater tables reached l0 cm, 30 cm, and 60 cm （Experiments I, II, and III）. Results show that both the soil temperature near shallow groundwater and the soil water content were effectively simulated by the PDV model. The root mean square errors of the temperature at depths of 5 cm, 10 cm, and 20 cm were 1.018℃, 0.909℃, and 0.255℃, respectively. The total heat flux generated the convergent and divergent planes in space-time fields with valley values of-161.5 W-m 2 at 7：30 and -234.6 W.m2 at 11：10 in Experiments II and III, respectively. The diurnal heat transport of the saturated soil occurred in five stages, while that of saturated-unsaturated and unsaturated soil profiles occurred in four stages because high moisture content led to high thermal conductivity, which hastened the heat transport.

关键词： heat transport heat flux soil temperature,water content shallow groundwater table

Measurements of heat transport by turbulent Rayleigh-Bénard convection in rectangular cells of widely varying aspect ratios

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Science China(Physics,Mechanics & Astronomy) 2013年第5期56卷 989-994页

作者： ZHOU Quan LU Hui LIU BoFang ZHONG BaoChang Shanghai Institute of Applied Mathematics and Mechanics and Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai University

High-precision measurements of the Nusselt number Nu for Rayleigh-B6nard （RB） convection have been made in rectangular cells of water （Prandtl number Pr ≈ 5 and 7） with aspect ratios （F~, Fy） varying between （1, 0.3） and （20.8, 6.3）. For each cell the data cover a range of a little over a decade of Rayleigh number Ra and for all cells they jointly span the range 6x105 〈 Ra 〈1011. The two implicit equations of the Grossmann-Lohse （GL） model together with the empirical finite conductivity cor- rection factorf（X） were fitted to obtain estimates of Nu∞ in the presence of perfectly conducting plates, and the obtained Nu∞ is independent of the cells＇ aspect ratios. A combination of two-power-law, Nu∞= O.025Ra0.357＋O.525Ra0.168, can be used to de- scribe Nu∞（Ra）. The fitted exponents 0.357 and 0.168 are respectively close to the predictions 1/3 and 1/5 of the 11μ. and 1Vμ re- gimes of the GL model. Furthermore, a clear transition from the II. regime to the IVμ regime with increasing Ra is revealed.

关键词： Rayleigh-Benard convection turbulent thermal convection heat transport

heat transport of Non-Local Effect with Modulated SMBI on HL-2A

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Chinese Physics Letters 2009年第3期26卷 163-165页

作者：孙红娟丁玄同姚良骅冯北滨刘泽田商亚东李伟李雪泓段旭如杨青巍 Southwestern Institute of Physics PO Box 432 Chengdu 610041

Modulated supersonic molecular beam （SMB） injection is introduced to study transport features of non-local transport phenomenon on HL-2A. Repetitive non-local effect induced by modulated SMBI allows Fourier trans-formation of the temperature perturbation, yielding detailed investigation of the pulse propagation. Fourier analysis provides evidence for existence of internal transport barriers. Meanwhile, experimental progress of nonlocal effect was made in the HL-2A Tokamak in 200Z The core electron temperature Te rise increases from 18% to more than 40% and the duration of the Te rise could be prolonged by changing the conditions of SMB injection.

关键词： TOKAMAK PLASMAS Plasmas heat transport Pulse propagation transport Server Message Block Fourier Transform Tokamak devices

Modeling Arctic Ocean heat transport and warming episodes in the 20th century caused by the intruding Atlantic Water

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Chinese Journal of Polar Science 2008年第2期19卷 159-167页

作者： Wang Jia Jin Meibing Jun Takahashi Tatsuo Suzuki Igor V Polyakov Kohei Mizobata Moto Ikeda Fancois J. Saucier Markus Meier NOAA Great Lakes Environmental Research Laboratory 4840 S State Road Ann Arbor Michigan 48108 USA International Arctic Research Center University of Alaska Fairbanks 930 Koyukuk Dr. Fairbanks AK 99775USA Frontier Research Center for Global Change 3173-25 Showamachi Kanazawa-ku Yokohama City Kanagawa236-0001 Japan Department of Ocean Science Tokyo University of Marine Science and Technology Tokyo Japan Graduate School of Earth and Environmental Science Hokkaido University Sapporo Hokkaido Japan Institute of Ocean Science University of Quebec at Rimouski 310 Ursulines Street Rimouski G5L 3A1 Canada Rossby Centre Swedish Meteorological and Hydrological Institute Sweden

This study investigates the Arctic Ocean warming episodes in the 20th century using both a high-resolution coupled global climate model and historical observations. The model, with no flux adjustment, reproduces well the Atlantic Water core temperature （AWCT） in the Arctic Ocean and shows that four largest decadalscale warming episodes occurred in the 1930s, 70s, 80s, and 90s, in agreement with the hydrographic observational data. The difference is that there was no pre-warming prior to the 1930s episode, while there were two pre-warming episodes in the 1970s and 80s prior to the 1990s, leading the 1990s into the largest and prolonged warming in the 20th century. Over the last century, the simulated heat transport via Fram Strait and the Barents Sea was estimated to be, on average, 31.32 TW and 14.82 TW, respectively, while the Bering Strait also provides 15.94 TW heat into the west- ern Arctic Ocean. heat transport into the Arctic Ocean by the Atlantic Water via Fram Strait and the Barents Sea correlates significantly with AWCT （ C = 0.75 ） at 0- lag. The modeled North Atlantic Oscillation （NAO） index has a significant correlation with the heat transport （ C = 0.37 ）. The observed AWCT has a significant correlation with both the modeled AWCT （ C =0.49） and the heat transport （ C =0.41 ）. However, the modeled NAO index does not significantly correlate with either the observed AWCT （ C = 0.03 ） or modeled AWCT （ C = 0.16 ） at a zero-lag, indicating that the Arctic climate system is far more complex than expected.

关键词： Arctic Ocean heat transport warming episodes modeling.

The annual mean sketches and climatological variability of the volume and heat transports through the inter-basin passages:A study based on 1 400-year spin up of MOM4p1

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Acta Oceanologica Sinica 2014年第9期33卷 12-24页

作者： ZHU Yaohua WEI Zexun WANG Yonggang GUAN Yuping WANG Xinyi Key Laboratory of Marine Science and Numerical Modeling First Institute of Oceanography State Oceanic Administration State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences

The annual mean volume and heat transport sketches through the inter-basin passages and transoceanic sections have been constructed based on 1400-year spin up results of the MOM4p 1. The spin up starts from a state of rest, driven by the monthly climatological mean force from the NOAAWorld Ocean Atlas （1994）. The volume transport sketch reveals the northward transport throughout the Pacific and southward transport at all latitudes in the Atlantic. The annual mean strength of the Pacific-Arctic-Atlantic through flow is 0.63x106 m3/s in the Bering Strait. The majority of the northward volume transport in the southern Pacific turns into the Indonesian through flow （ITF） and joins the Indian Ocean equatorial current, which subse- quently flows out southward from the Mozambique Channel, with its majority superimposed on the Ant- arctic Circumpolar Current （ACC）. This anti-cyclonic circulation around Australia has a strength of 11 x 106 ms /s according to the model-produced result. The atmospheric fresh water transport, known as P-E^R （pre- cipitation minus evaporation plus runoff）, constructs a complement to the horizontal volume transport of the ocean. The annual mean heat transport sketch exhibits a northward heat transport in the Atlantic and poleward heat transport in the global ocean. The surface heat flux acts as a complement to the horizontal heat transport of the ocean. The climatological volume transports describe the most important features through the inter-basin passages and in the associated basins, including： the positive P-E＋R in the Arctic substantially strengthening the East Greenland Current in summer; semiannual variability of the volume transport in the Drake Passage and the southern Atlantic-Indian Ocean passage; and annual transport vari- ability of the ITF intensifying in the boreal summer. The climatological heat transports show heat storage in July and heat deficit in January in the Arctic; heat storage in January and heat deficit in July in the

关键词： volume transport heat transport global ocean circulation inter-basin passages climatologicalvariability

Experimental Investigation on Thermal Characteristics of Long Distance Loop heat Pipes

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Journal of Thermal Science 2022年第3期31卷 741-750页

作者： ZHAO Ya’nan YAN Tao LIANG Jingtao Key Laboratory of Space Energy Conversion Technology Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100190China

Loop heat pipes(LHPs)are attractive two-phase thermal control devices for satellites,electronics and many other *** are capable of transporting heat efficiently for long distances up to several meters at any *** paper investigated the heat transfer characteristics of loop heat pipes with long distances and small diameter transport *** stainless steel tubes of 2 mm and 3 mm in inner diameters were chosen as liquid lines and vapor lines of the *** local thermal resistances in the evaporator of the 6 m-LHP were researched and analyzed,which indicated that the thermal resistance between the aluminum block and the vapor in the vapor channel accounted for a major proportion of the total thermal *** effect of heat sink temperatures on the performance of the 6 m-LHP were compared with 10°C,15°C,20°C and 25°C cooling water ***,the thermal characteristics of LHPs with transport distances of 2 m and 16 m were also experimentally *** 16 m-LHP could achieve a heat transfer capacity of 100 W and the 2 m-LHP could reach more than 339 W,on the premise of the evaporator temperature below 100°*** thermal resistance of the 2 m-LHP could achieve 0.125°C/W.

关键词： loop heat pipe thermal management heat transport long distance thermal resistance