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Conductive property of Zr0.1Fe0.9V1.1Mo0.9O7 with low thermal expansion
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作者 何小可 戚恒 +3 位作者 徐启 刘献省 许磊 袁保合 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期244-248,共5页
Low thermal expansion materials are mostly ceramics with low conductive property,which limits their applications in electronic devices.The poor conductive property of ceramic ZrV2O7 could be improved by bi-substitutio... Low thermal expansion materials are mostly ceramics with low conductive property,which limits their applications in electronic devices.The poor conductive property of ceramic ZrV2O7 could be improved by bi-substitution of Fe and Mo for Zr and V,accompanied with low thermal expansion.Zr0.1Fe0.9V1.1Mo0.9O7 has electrical conductivity of 8.2×10^-5 S/cm and 9.41×10^4 S/cm at 291 K and 623 K,respectively.From 291 K to 413 K,thermal excitation leads to the increase of carrier concentration,which causes the rapid decrease of resistance.At 413–533 K,the conductivity is unchanged due to high scattering probability and a slowing increase of carrier concentration.The conductivity rapidly increases again from 533 K to 623 K due to the intrinsic thermal excitation.The thermal expansion coefficient of Zr0.1Fe0.9V1.1Mo0.9O7 is as low as 0.72×10^6 K^-1 at 140–700 K from the dilatometer measurement.These properties suggest that Zr0.1Fe0.9V1.1Mo0.9O7 has attractive application in electronic components. 展开更多
关键词 low THERMAL EXPANSION CONDUCTIVITY THERMAL EXCITATION electric IMPEDANCE
An integrated approach to assess the ecological and chemical status of lakes with HOD/AHOD:a case study of two lakes 预览
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作者 Serdar GONCU Erdem ALBEK 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第1期146-159,共14页
The thermal stratification of the lakes impedes the transfer of atmospheric oxygen into the lower layers of the lake.In lakes which are affected by diverse anthropogenic infl uences,the increasing organic matter amoun... The thermal stratification of the lakes impedes the transfer of atmospheric oxygen into the lower layers of the lake.In lakes which are affected by diverse anthropogenic infl uences,the increasing organic matter amounts lead to a sharp decrease in hypolimnetic oxygen amounts,aided by thermal stratification,and anaerobic conditions arise.The determination of hypolimnetic oxygen demand(HOD)and areal hypolimnetic oxygen demand(AHOD)and their monitoring represent an integrated approach to investigate the oxygenation of lakes,the nutrient conditions,and the physicochemical dynamics.In this study,two lakes differing by size and affected by different anthropogenic sources,are investigated in this respect.At first,bathymetric studies were conducted to determine the depth,surface area,and volume relationships.Then,based on monitoring studies conducted in 2013 and 2014,the thermal stratification dynamics and layer properties were established using the relative thermal resistance to mixing(RTRM)index based on temperature and density profiles.Following this,the oxygen depletion rates were determined by oxygen and temperature profiling in the hypolimnion.For the years of 2013 and 2014,the AHOD values for the Borabey Pond which is far from anthropogenic infl uences,were found to be 0.848 and 0.569 g O 2/(m·d),respectively.The AHOD values for the Porsuk Reservoir which was overburdened for years by industrial and domestic pollution were found to be 4.263 and 5.099 g O 2/(m·d),larger than its counterpart by almost sevenfold.The HOD and AHOD monitoring can be considered to a valuable tool for assessing the ecological and chemical status of lakes within Annex 5 of the Water Framework Directive and as an integrated approach to assess and monitor the status of lakes. 展开更多
关键词 hypolimnetic OXYGEN demand(HOD) areal hypolimnetic OXYGEN demand(AHOD) THERMAL stratification relative THERMAL resistance to mixing(RTRM) Borabey POND Porsuk Dam
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Thermal state calculation of chamber in small thrust liquid rocket engine for steady state pulsed mode
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作者 Alexey Gennadievich VOROBYEV Svatlana Sergeevna VOROBYEVA +1 位作者 Lihui ZHANG Evgeniy Nikolaevich BELIAEV 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第2期253-262,共10页
This paper presents a method of thermal state calculation of combustion chamber in small thrust liquid rocket engine. The goal is to predict the thermal state of chamber wall by using basic parameters of engine: thrus... This paper presents a method of thermal state calculation of combustion chamber in small thrust liquid rocket engine. The goal is to predict the thermal state of chamber wall by using basic parameters of engine: thrust level, propellants, chamber pressure, injection pattern, film cooling parameters, material of wall and their coating, etc. The difficulties in modeling the startup and shutdown processes of thrusters lie in the fact that there are the conjugated physical processes occurring at various parameters for non-design conditions. A mathematical model to predict the thermal state of the combustion chamber for different engine operation modes is developed. To simulate the startup and shutdown processes, a quasi-steady approach is applied by replacing the transient process with time-variant operating parameters of steady-state processes. The mathematical model is based on several principles and data commonly used for heat transfer modeling: geometry of flow part, gas dynamics of flow, thermodynamics of propellants and combustion spices, convective and radiation heat flows, conjugated heat transfer between hot gas and wall, and transient approach for calculation of thermal state of construction. Calculations of the thermal state of the combustion chamber in single-turn-on mode show good convergence with the experimental results. The results of pulsed modes indicate a large temperature gradient on the internal wall surface of the chamber between pulses and the thermal state of the wall strongly depends on the pulse duration and the interval. 展开更多
关键词 Combustion CHAMBER Film cooling Mathematical model NONSTATIONARY THERMAL MODE SMALL THRUST liquid rocket engine Steady pulse MODE THERMAL state
Modification of NiCoCrAlY with Pt: Part Ⅱ. Application in TBC with pure metastable tetragonal(t’) phase YSZ and thermal cycling behavior
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作者 Chuntang Yu He Liu +3 位作者 Chengyang Jiang Zebin Bao Shenglong Zhu Fuhui Wang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第3期350-359,共10页
A thermal barrier coating system comprising Pt-modified NiCoCrAlY bond coating and nanostructured 4mol.% yttria stabilized zirconia(4YSZ, hereafter) top coat was fabricated on a second generation Ni-base superalloy. T... A thermal barrier coating system comprising Pt-modified NiCoCrAlY bond coating and nanostructured 4mol.% yttria stabilized zirconia(4YSZ, hereafter) top coat was fabricated on a second generation Ni-base superalloy. Thermal cycling behavior of NiCoCrAlY-4 YSZ thermal barrier coatings(TBCs) with and without Pt modification was evaluated in ambient air at 1100?C up to 1000 cycles, aiming to investigate the effect of Pt on formation of thermally grown oxide(TGO) and oxidation resistance. Results indicated that a dual layered TGO, which consisted of top(Ni,Co)(Cr,Al)2O4 spinel and underlying α-Al2O3, was formed at the NiCoCrAlY/4 YSZ interface with thickness of 8.4μm, accompanying with visible cracks at the interface. In contrast, a single-layer and adherent α-Al2O3 scale with thickness of 5.6μm was formed at the interface of Pt-modified NiCoCrAlY and 4 YSZ top coating. The modification of Pt on NiCoCrAlY favored the exclusive formation of α-Al2O3 and the reduction of TGO growth rate, and thus could effectively improve overall oxidation performance and extend service life of TBCs. Oxidation and degradation mechanisms of the TBCs with/without Pt-modification were discussed. 展开更多
关键词 Pt-modification NICOCRALY THERMAL barrier coating(TBC) THERMAL cycling Thermally grown oxide(TGO)
Influence of Microstructures on Thermal Shock and Sintering Behavior of YSZ-based Thermal Barrier Coatings 预览
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作者 Kirsten Bobzin Lidong Zhao +1 位作者 Mehmet Ote Tim Konigstein 《表面技术》 EI CAS CSCD 北大核心 2019年第4期28-33,共6页
In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal b... In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal barrier coatings exhibited similar overall porosities, but significantly different microstructures. Application of the special spray powder prepared by high energy ball milling led to a microstructure with numerous inclusions of semi-molten agglomerates, which introduced a plethora of clusters of fine pores into the coating and several more microstructural defects. This microstructure resulted in a significantly better thermal shock behavior compared to the conventional thermal barrier coating. The heat treatment of both thermal barrier coatings atθ=1150℃for t=100 h led to a sintering of both coatings. The results were reduced overall porosity and significantly increased fracture toughness. A correlation between the fracture toughness of both coatings after the heat treatment and the thermal shock life time could not be identified. 展开更多
关键词 THERMAL barrier coating ZrO2-7%Y2O3 high energy ball MILLING THERMAL shock
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发动机热管理技术研究 预览
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作者 张强 韩令海 +1 位作者 王占峰 史鹏礼 《汽车文摘》 2019年第6期58-62,共5页
发动机热管理技术是通过冷却策略的控制改善发动机冷起动暖机速度,从而降低发动机冷起动工况油耗和排放的关键技术。本文深入挖掘了国际上文献资料,整理了电子节温器技术、电动水泵技术、分体冷却技术、智能热管理技术,并针对不同技术... 发动机热管理技术是通过冷却策略的控制改善发动机冷起动暖机速度,从而降低发动机冷起动工况油耗和排放的关键技术。本文深入挖掘了国际上文献资料,整理了电子节温器技术、电动水泵技术、分体冷却技术、智能热管理技术,并针对不同技术对发动机冷起动暖机速度的改善情况,对国际上发动机热管理技术进展进行了归纳、总结和分析。 展开更多
关键词 发动机 热管理 电子节温器 电动水泵 智能热管理
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Effect of building interface form on thermal Check foi comfort in gymnasiums in hot and humid climates
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作者 Xiaodan Huang Xiaoli Ma Qingyuan Zhang 《建筑学研究前沿(英文版)》 CSCD 2019年第1期32-43,共12页
The thermal environment and thermal comfort of a building are greatly affected by the desig n of the build ing interface form. Most con temporary architectural designs con sider only the relations between architectura... The thermal environment and thermal comfort of a building are greatly affected by the desig n of the build ing interface form. Most con temporary architectural designs con sider only the relations between architectural form and architectural beauty. Few studies on the correlati on of architectural form and thermal comfort address the in flue nee of architectural form on thermal comfort and thermal environment. These studies are particularly important for gymnasium architectures located in hot and humid areas, which have high requirements for thermal comfort. This paper presents an experimental investigati on and an an alysis of the effect of the building in terface form of gymnasiums on thermal comfort in hot and humid subtropical regions during summer. Results showed that the influence of the top interface forms on thermal comfort is mainly dominated by the mea n radiant temperature, which could be con trolled to improve thermal comfort. The in fluence of side interface forms on thermal comfort is mainly domi nated by air velocity, and thermal comfort could be improved by promoting natural ventilation on the side interface form design to reduce indoor heat. This research enhanced our understanding of the relation between the in terface form and the thermal comfort of gymnasiums. In addition, this paper provides a theoretical reference for the sustainable design of gymnasiums in hot and humid climates. 展开更多
关键词 THERMAL COMFORT THERMAL environment Interface FORM Standard effective temperature GYMNASIUM HOT and humid climate
Thermal Performance and Mechanics Characteristic for Double Layer Microchannel Heat Sink
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作者 XU Yupeng GONG Liang +2 位作者 LI Yongtong BAI Zhang XU Minghai 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期271-282,共12页
Double layer micro-channel heat sink(DLMCHS) has been widely used in various electronic devices;however, the existence of the nonuniform thermal strain distribution in actual operation has adverse effect on the overal... Double layer micro-channel heat sink(DLMCHS) has been widely used in various electronic devices;however, the existence of the nonuniform thermal strain distribution in actual operation has adverse effect on the overall stability. In this paper, two optimized designs of DLMCHS with cutting baffles on top and bottom layers are presented based on the traditional DLMCHS. The heat transfer and thermal stress performance are numerically analyzed and compared with the traditional DLMCHS. The results indicate that cutting baffles of micro-channels remarkably improves heat transfer and thermal stress performance. The optimized design with cutting baffles on the bottom layer decreases thermal strain but deteriorates heat transfer performance. The model with cutting baffles on the top layer has better combined thermal strain and heat transfer performance, which reduces thermal strain by about 1.5 times and enhances heat transfer by about 26.5%. For the design with cutting baffles on the top board, adding metal foam in the inlet collector can decrease the total minimum thermal strain by 51.4% and maximum temperature by 1.4 K, and increase the Nusselt number by 15%. These results indicate that DLMCHS with cutting baffles on the top layer has great potential for thermal managements on electronic devices with high power density. 展开更多
关键词 DOUBLE LAYER MICRO-CHANNEL heat SINK THERMAL STRAIN THERMAL performance optimized design
Thermal and saline tolerance of Antarctic krill Euphausia superba under controlled in-situ aquarium conditions 预览
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作者 ZHU Guoping LIU Zijun +3 位作者 YANG Yang WANG Zhen YANG Wenjie XU Liuxiong 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第3期1080-1089,共10页
As a key species of the Southern Ocean ecosystem,the thermal and saline tolerances of Antarctic krill(Euphausia superb a Dana)are relatively unknown because of the challenging environment and complicated situations ne... As a key species of the Southern Ocean ecosystem,the thermal and saline tolerances of Antarctic krill(Euphausia superb a Dana)are relatively unknown because of the challenging environment and complicated situations needed for observation have inhibited in-situ experiments in the field.Hence,the thermal and saline tolerance of krill were examined under in-situ aquarium conditions with different controlled scenarios.According to the experiments,the critical lethal times of krill were 24h,2h and 0.5h under 9℃,12℃,and 15℃,respectively,and the estimated 50%lethal times were about 17.1 h and 1.7 h under 12℃and 15℃,respectively.Additionally,the critical lethal times(the estimated 50%lethal times)of krill were approximately 14h and 0.5h(about 22.9 h and 1.7 h)of salinity under 19.7 and 15.9,respectively.The observed critical and 50%lethal times of krill were 0.5 h and approximately 1.4 h,respectively,salinity under 55.2.The critical and 50%lethal temperatures of krill were 13℃and approximately 14.2℃,respectively.Additionally,the critical and 50%lethal salinity was 19.6 and approximately 17.5 for the lower saline(below normal oceanic salinity[34.4])environment and 50.3 and approximately 53.2 for the higher saline(above 34.4)environment,respectively.The upper thermal and saline preferences of krill can be considered 6℃and 26.8 to 41.2,respectively.These results can provide potential scenarios for predicting the possible fate of this key species in the Southern Ocean. 展开更多
关键词 Euphausia superba THERMAL TOLERANCE SALINE TOLERANCE THERMAL PREFERENCE IN-SITU AQUARIUM experiment
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Investigation on the key aspects of l-arginine para nitrobenzoate monohydrate single crystal:A non-linear optical material
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作者 Sonia N.Vijayan +5 位作者 Mahak Vij Kanika Thu krai Naghma Khan D.Haranath Rajnikant M.S.Jayalakshmy 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第3期701-708,共8页
In the contemporary days,non-linear optical materials(NLO)are getting higher attention as per the increasing demand in optical communication and data storage technology.Consequently,they explore various physical prope... In the contemporary days,non-linear optical materials(NLO)are getting higher attention as per the increasing demand in optical communication and data storage technology.Consequently,they explore various physical properties of the NLO material for their industrial applications.In current report,l-arginine p-nitrobenzoate monohydrate(LANB)single crystals were obtained by adopting slow cooling technique.The structural confirmation of grown single crystal was carried out using single crystal X-Ray diffractometer.Presence of strain within single crystal was deduced using Hall–Williamson relation.Various defects associated within single crystal were assessed using high resolution XRD.Additionally,its crystalline quality was again confirmed by time resolved photoluminescence spectroscopy(TRPL).Using transmission spectra,the cut off wavelength and band gap of the host material was determined to be nearly 420 nm and 2.9 e V respectively.The dielectric property has been recorded by varying the frequency ranging from 50 Hz to 100 k Hz.The curve suggests that dielectric loss value is less at high frequency ensures the suitability of crystal in photonics and NLO based devices.The laser damage threshold values were also measured for single and multiple shots.Thermal parameters of the titled compound were calculated using PPE.In photoconductivity measurement,negative photoconductivity has been observed in titled compound.Microhardness studies were also performed on single crystal to explore its mechanical properties. 展开更多
关键词 PHOTOLUMINESCENCE THERMAL conductivity Specific heat THERMAL effusivity Damage threshold
Modeling of thermal conductivity and density of alumina/silica in water hybrid nanocolloid by the application of Artificial Neural Networks
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作者 Sathishkumar Kannaiyan Chitra Boobalan +1 位作者 Fedal Castro Nagarajan Srinivas Sivaraman 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第3期726-736,共11页
In this research work,the thermal conductivity and density of alumina/silica(Al2O3/SiO2)in water hybrid nanofluids at different temperatures and volume concentrations have been modeled using the artificial neural netw... In this research work,the thermal conductivity and density of alumina/silica(Al2O3/SiO2)in water hybrid nanofluids at different temperatures and volume concentrations have been modeled using the artificial neural networks(ANN).The nanocolloid involved in the study was synthesized by the two-step method and characterized by XRD,TEM,SEM–EDX and zeta potential analysis.The properties of the synthesized nanofluid were measured at various volume concentrations(0.05%,0.1%and 0.2%)and temperatures(20 to 60°C).Established on the observational data and ANN,the optimum neural structure was suggested for predicting the thermal conductivity and density of the hybrid nanofluid as a function of temperature and solid volume concentrations.The results indicate that a neural network with 2 hidden layers and 10 neurons have the lowest error and a highest fitting coefficient of thermal conductivity,whereas in the case of density,the structure with 1 hidden layer consisting of 4 neurons proved to be the optimal structure. 展开更多
关键词 THERMAL CONDUCTIVITY Modeling HYBRID NANOCOLLOIDS ANN THERMAL energy
Impact of Technology and Innovation on Adaptation of Architectonic Tradition for a Sustainable Future in the Middle East 预览
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作者 Isra’a S. Fardous Amar Bennadji 《土木工程与建筑:英文版》 2019年第4期273-281,共9页
Over the last three decades,the Middle East(ME)region has experienced rapid economic and infrastructure transformation.Most of the dwelling places have fully adopted western architectural trends ignoring both the cult... Over the last three decades,the Middle East(ME)region has experienced rapid economic and infrastructure transformation.Most of the dwelling places have fully adopted western architectural trends ignoring both the cultural and environmental fundamentals of the region.The paper is incorporated with a Ph.D.research,it is cognizant of the fact that socio-demographics has changed over the years.Large cities in the region have experienced massive population growth which has made traditional architectural(TA)less suitable.This study is focused on identifying how recent innovation and technologies can be used in the adaptation of architectonic traditions.Seeking to identify how the inherent sustainability characteristics of TA can be integrated with modern architectural studies for cultural relevant and sustainable dwellings in the ME.An investigation in houses in Riyadh City,Saudi Arabia where the climate is mostly hot and arid will serve as the case study for this research because of its strong history in TA coupled with proliferation of western architecture.Research will utilize a qualitative data because it is inclusive of situational descriptions,events and observed behaviors.It will enable findings based from the participants view to cultural existence and change,and meanings important to them.Moreover,researcher will rely on the themes as the main backbone on what the study is trying to bring out.Thus,will ensure findings end up with what is appreciated for environmental housing application not only based on climate control but also based on other psychological and visual components. 展开更多
关键词 Environmental TRADITIONAL ARCHITECTURE thermal COMFORT transitional ARCHITECTURE and WELL-BEING
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Review on fate of chlorine during thermal processing of solid wastes
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作者 Peng Lu Qunxing Huang +3 位作者 A.C.(Thanos)Bourtsalas Nickolas J.Themelis Yong Chi Jianhua Yan 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期13-28,共16页
Chlorine(Cl) is extensively present in solid wastes, causing significant problems during the thermal conversion of waste to energy or fuels, by combustion, gasification or pyrolysis.This paper introduces the analytica... Chlorine(Cl) is extensively present in solid wastes, causing significant problems during the thermal conversion of waste to energy or fuels, by combustion, gasification or pyrolysis.This paper introduces the analytical methods for determining the Cl content in solid materials and presents the concentrations of Cl in various types of wastes, as reported in literature. Then, it provides a comprehensive analysis on the Cl emission behavior and Cl species formed during the thermal processing of the inorganic and organic Cl sources. The challenges resulted from the reactions between the formed Cl species and the ferrous metals, the heavy metals and the organic matters are summarized and discussed, e.g., high temperature corrosion, heavy metal evaporation and dioxin formation. The quality degradation of products(oil, char and syngas) by Cl is analyzed. Finally, the available controlling methods of Cl emission, including pre-treatment(water washing, sorting,microwave irradiation and stepwise pyrolysis) and in-furnace(absorbents, co-treatment and catalysts) methods are assessed. 展开更多
关键词 CHLORINE Solid WASTES Thermal PROCESSING EMISSION Controlling methods
Alkyl group functionalization-induced phonon thermal conductivity attenuation in graphene nanoribbons
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作者 王彩云 鲁爽 +1 位作者 于晓东 李海鹏 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期522-526,共5页
We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain lengt... We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain length and concentration of alkyl groups caused remarkable reduction of phonon thermal conductivity in functionalized ZGNRs. Phonon spectra analysis showed that functionalization of ZGNR with alkyl functional groups induced phonon–structural defect scattering, thus leading to the reduction of phonon thermal conductivity of ZGNR. Our study showed that surface functionalization is an effective routine to tune the phonon thermal conductivity of GNRs, which is useful in graphene thermal-related applications. 展开更多
关键词 graphene nanoribbons(GNRs) thermal CONDUCTIVITY PHONON spectrum surface FUNCTIONALIZATION molecular dynamics simulations
Surface stabilized cubic phase of CsPbI3 and CsPbBr3 at room temperature
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作者 杨凤 王聪 +3 位作者 潘宇浩 周谐宇 孔祥华 季威 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期237-243,共7页
Inorganic halide perovskites CsPbX3 (X = I,Br) have attracted tremendous attention in solar cell applications.However,the bulk form of the cubic phase CsPbX3,which offers moderate direct bandgaps,is metastable at room... Inorganic halide perovskites CsPbX3 (X = I,Br) have attracted tremendous attention in solar cell applications.However,the bulk form of the cubic phase CsPbX3,which offers moderate direct bandgaps,is metastable at room temperature and tends to transform into a tetragonal or orthorhombic phase.Here,our density functional theory calculation results found that the surface energies of the cubic phase are smaller than those of the orthorhombic phase,although the bulk counterpart of the cubic phase is less stable than that of the orthorhombic phase.These results suggest a surface stabilization strategy to maintain the stability of the cubic phase at room temperature that an enlarged portion of surfaces shall change the relative stability of the two phases in nanostructured CsPbX3.This strategy,which may potentially solve the long-standing stability issue of cubic CsPbX3,was demonstrated to be feasible by our calculations in zero-,one-,and two-dimensional nanostructures.In particular,confined sizes from few to tens of nanometers could keep the cubic phase as the most thermally favored form at room temperature.Our predicted values in particular cases,such as the zero-dimensional form of CsPbI3,are highly consistent with experimental values,suggesting that our model is reasonable and our results are reliable.These predicted critical sizes give the upper and lower limits of the confined sizes,which may guide experimentalists to synthesize these nanostructures and promote likely practical applications such as solar cells and flexible displays using CsPbX3 nanostructures. 展开更多
关键词 INORGANIC PEROVSKITE solar cell thermal stability SURFACE energy NANOWIRE quantum dot NANOPLATE
Electrospun and in situ self-polymerization of polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection
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作者 Chun-Hong Wang Li-Min Hu +1 位作者 Zhi-Feng Wang Ming Zhang 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第3期252-258,共7页
In this work, the polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection were successfully fabricated by electrospunning and followed by in situ self-polymerization. Scanning electron micros... In this work, the polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection were successfully fabricated by electrospunning and followed by in situ self-polymerization. Scanning electron microscopy(SEM) and energy-dispersive spectroscopy(EDS) results show that there are no beads on the smooth surface of the nanofibers and gadolinium elements are uniformly dispersed in the matrix. The thermal analysis and FTIR results prove that gadolinium methacrylate is induced in situ selfpolymerization during the heat treatment. The leaching rate of Gd3+ decreases from 79.97% to 10.74% tested by lowfield nuclear magnetic resonance(LF-NMR) method after the self-polymerization of gadolinium methacrylate in the matrix when the nanofibers were immersed in water for7 days. The thermal neutron shielding analysis calculated by MCNP program shows that above 99% thermal neutrons are absorbed when traveling through the 2-mm-thick polyacrylonitrile containing gadolinium nanofibers. 展开更多
关键词 GADOLINIUM POLYACRYLONITRILE ELECTROSPINNING In situ SELF-POLYMERIZATION Thermal neutron shielding
CO2 conversion by thermal plasma with carbon as reducing agent: high CO yield and energy efficiency
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作者 刘朋 刘雪松 +5 位作者 沈俊 印永祥 杨涛 黄强 Daniel AUERBACH Aart W KLEIYN 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第1期1-4,共4页
A key problem in CO2 conversion by thermal plasma is suppressing the inverse reactions,CO+O→CO2 and CO+0.5O2→?CO2, to simultaneously obtain high CO yield and energy efficiency. This can be done by quickly quenching ... A key problem in CO2 conversion by thermal plasma is suppressing the inverse reactions,CO+O→CO2 and CO+0.5O2→?CO2, to simultaneously obtain high CO yield and energy efficiency. This can be done by quickly quenching the decomposed gas or rapidly taking away free oxygen from decomposed gas. In this paper, experiments of CO2 conversion by thermal plasma with carbon as a reducing agent are presented. Carbon quickly devoured free oxygen in thermal plasma decomposed gas, and not only is the inverse reaction completely suppressed, but the discharge energy to form oxygen atoms, oxygen molecular, and thermal energy is also reused.A CO2 conversion rate of 67%–94% and the corresponding electric energy efficiency of about 70% are achieved, both are much higher than that seen so far by other plasma implementations. 展开更多
关键词 thermal PLASMA CO2 CONVERSION CO2 UTILIZATION
A Review about Thermal Comfort in Aircraft
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作者 FAN Juli ZHOU Qiongyao 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期169-183,共15页
Thermal comfort is an important factor which affects both work efficiency and life quality. On the basis of satisfying the normal life of the crew and reliable work of equipment, the thermal comfort is increasingly pu... Thermal comfort is an important factor which affects both work efficiency and life quality. On the basis of satisfying the normal life of the crew and reliable work of equipment, the thermal comfort is increasingly pursued through the design of the environmental control system of modern craft. Thus, a comprehensive survey of the thermal comfort in the cockpit is carried out. First of all, factors affecting the thermal comfort in aircraft cabin are summarized, including low relative humidity, mean radiant temperature, colored light, human metabolic rate and gender, among which the first three factors are environmental factors and the other two are human factors. Although noise is not a factor affecting thermal comfort, it is an important factor in the overall satisfaction of the aircraft cabin environment. Then the thermal comfort prediction models are introduced, including thermal comfort models suitable for steady state uniform environment and thermal comfort models suitable for transient non-uniform environment. Then the limitations of the typical thermal comfort models applied to aircraft are discussed. Since the concept of thermal adaptation has been gradually accepted in recent years, many field studies on thermal adaptation have been carried out. Therefore, the adaptive thermal comfort models are summarized and analyzed systematically in this paper. At present, mixing ventilation(MV) system is widely used in most commercial aircraft. However, the air quality under the MV system is very poor, and contaminants cannot be effectively eliminated. So a noticeable shift is the design of ventilation system for cabin drawing lessons from the surface buildings. Currently, the most interesting question is that whether the traditional mixing ventilation(MV) system in an aircraft can be replaced by or combined with displacement ventilation(DV) system without decreasing thermal comfort. A reduction of energy consumption is a valuable gain. Additionally, various seat personalized ventilation systems have also been propose 展开更多
关键词 AIRCRAFT thermal COMFORT energy EFFICIENT ventilation system NUMERICAL simulation
两种热电分离式基板导热性能的对比研究 预览
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作者 秦典成 肖永龙 《电子器件》 CAS 北大核心 2019年第1期66-69,共4页
基于热电分离式设计理念,开发出FR4/Cu与FR4/AlN两种高导热散热基板,并利用SMT工艺将13W的OsramS2W型LED灯珠分别与上述两种散热基板焊接后组装成LED模组;利用半导体制冷温控台恒定散热基板底部温度后,使用结温测试仪对LED的结温进行了... 基于热电分离式设计理念,开发出FR4/Cu与FR4/AlN两种高导热散热基板,并利用SMT工艺将13W的OsramS2W型LED灯珠分别与上述两种散热基板焊接后组装成LED模组;利用半导体制冷温控台恒定散热基板底部温度后,使用结温测试仪对LED的结温进行了测试。同时借助直流电源和积分球分别对LED的总功率和光功率进行了测量后得到了模组的热功率值。最后根据LED结温测试结果与热功率值计算得出了模组的热阻值,并在此基础上对两种基板的散热性能进行了对比研究。结果表明,FR4/AlN基板的散热性能较之FR4/Cu基板稍逊。当使用FR4/Cu基板散热时,LED的结温和热阻分别是49.72℃、2.21℃/W。当使用FR4/AlN基板散热时,LED的结温和热阻分别是51.32℃、2.32℃/W。 展开更多
关键词 热电分离 LED 模组 FR4/Cu基板 FR4/AlN基板 结温 热阻 散热性能
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Effect of Modified Vermiculite on the Interface of a Capric Acid-expanded Vermiculite Composite Phase Change Material with Phase Transition Kinetics
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作者 ZHANG Hongguang ZHU Jiaoqun +2 位作者 CHENG Xiaomin ZHOU Weibing LIU Fengli 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第2期345-352,共8页
A new type of capric acid(CA)-acid expanded vermiculite(AEV) composite phase change material(PCM) with improved adsorption ability and interface adhesive strength was developed. Through the analysis of non-isothermal ... A new type of capric acid(CA)-acid expanded vermiculite(AEV) composite phase change material(PCM) with improved adsorption ability and interface adhesive strength was developed. Through the analysis of non-isothermal phase transition kinetics, modified vermiculite was observed to change and affect the phase transformation mechanism of the composite. AEV was treated with hydrochloric acid to improve the specific surface area and micro-pore structure. The surface area measured by BET increased from 81.94 m2/g for expanded vermiculite(EV) to 544.13 m2/g for AEV. CA-EV and CA-AEV composite PCMs were prepared by direct impregnation. The non-isothermal phase transition isotherms of CA-EV and CA-AEV were recorded by DSC at different heating rates(1, 5, 10, 15, and 20 ℃/min), which indicated that the phase transition rate increased with the heating rate and the phase transition process changed. Kinetics parameters were analyzed by a double extrapolation method. The activation energy(E) under the original state(Eα→0) of CA-AEV and CA-EV was 1 117 kJ/mol and 937 kJ/mol, respectively, and 1 205 kJ/mol and 1 016 kJ/mol under the thermal equilibrium state(Eβ→0). The most probabilistic mechanism function of CA-AEV satisfied G(α)=α2/3, which followed the Mample special rule, and the function of CA-EV satisfied G(α)=[(1+α)1/3-1]2, which followed the anti-Jander function. 展开更多
关键词 modified VERMICULITE PHASE CHANGE material PHASE TRANSITION KINETICS thermal storage
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