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Thermoelectric properties of Bi0.5Sb1.4-xNaxIn0.1Te3 alloys

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Rare Metals 2019年第12期38卷 1187-1192页

作者： Yue-Zhen Jiang xing-Kai Duan School of Electronic Engineering Jiujiang UniversityJiujiang 332005China School of Mechanical and Materials Engineering Jiujiang UniversityJiujiang 332005China

The Bi(0.5)Sb(1.4-x)NaxIn(0.1)Te3(x=0.02-0.20)alloys were fabricated by high vacuum melting and hotpressing *** phase structures and morphology of the bulk samples were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM),*** of In and Na co-doping on the electrical and thermal transport properties were studied from room temperature to 500 *** coefficient of the Bi(0.5)Sb(1.5)Te3 can be enhanced by substituting Sb with In and Na at near room *** electrical conductivity of the In and Na co-doped samples is lower than that of the Bi(0.5)Sb(1.5)Te3 alloy from room temperature to 500 *** and Na co-doping of appropriate percentage optimizes the thermal conductivity of the Bi(0.5)Sb(1.5)Te3 *** minimum value of thermal conductivity of Bi(0.5)Sb(1.36)Na(0.04)In(0.1)Te3 alloy is 0.45 w·m^(-1) K^(-1) at 323 *** leads to a great improvement in the thermoelectric figure of merit(zT).The maximum zT value reaches 1.42 at 323 K.

关键词： Microstructure Co-doping Thermal conductivity Electrical properties

Long-Term Effects of Manure and Inorganic Fertilizers on Yield and Soil Fertility for a winter wheat-Maize System in Jiangsu, China

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Pedosphere 2006年第1期16卷 25-32页

作者： JIAng Dong H. HEngSDIJK DAI Ting-Bo w. de BOER JIng Qi CAO wei-xing Key Laboratory of Crop Growth Regulation Ministry of Agriculture Department of Agronomy Nanjing AgriculturalUniversity Nanjing 210095 （China） Plant Research International P. O. Box 16 6700 AA Wageningen （Netherlands）

winter wheat-maize rotations are dominant cropping systems on the North China Plain, where recently the use of organic manure with grain crops has almost disappeared. This could reduce soil fertility and crop productivity in the long run. A 20-year field experiment was conducted to 1) assess the effect of inorganic and organic nutrient sources on yield and yield trends of both winter wheat and maize, 2) monitor the changes in soil organic matter content under continuous wheat-maize cropping with different soil fertility management schemes, and 3) identify reasons for yield trends observed in Xuzhou City, Jiangsu Province, over a 20-year period. There were eight treatments applied to both wheat and maize seasons: a control treatment (C); three inorganic fertilizers, that is, nitrogen (N), nitrogen and phosphorus (NP), and nitrogen, phosphorus and potassium (NPK); and addition of farmyard manure (FYM) to these four treatments, that is, M, MN, MNP, and MNPK. At the end of the experiment the MN, MNP, and MNPK treatments had the highest yields, about 7 t wheat ha-1 and 7.5 t maize ha-1, with each about 1 t ha-1 more than the NPK treatments. Over 20 years with FYM soil organic matter increased by 80% compared to only 10% with NPK, which explained yield increases. However, from an environmental and agronomic perspective, manure application was not a superior strategy to NPK fertilizers. If manure was to be applied, though, it would be best applied to the wheat crop, which showed a better response than maize.

关键词： manure NPK-fertilizer soil organic matter Triticum aestivum L. Zea mays L.

Cretaceous dinosaur and crocodylomorph egg records of the Sanshui Basin,Guangdong Province,southern China

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Journal of Palaeogeography 2023年第3期12卷 401-418页

作者： Li-Da xing Zi-Sheng Guo Rui wu Chun-Lei Du Dong-Haow.ng w.Scott Persons IV State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences(Beijing)Beijing100083China School of the Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China Grandview Museum of Natural Science Guangzhou 510630Guangdong ProvinceChina School of Earth Sciences China University of Geosciences(Wuhan)Wuhan 430074Hubei ProvinceChina Mace Brown Museum of Natural History Department of Geology and Environmental GeosciencesCollege of CharlestonCharlestonSC 29401USA

This paper describes newly discovered dinosaur and crocodylomorph egg fragments from the Upper Cretaceous Sanshui and Dalangshan formations of the Sanshui Basin of Guangdong Province,southern *** the absence of macroscopic information,the eggshell specimens can be identified to the oofamilies Prismatoolithidae,Elongatoolithidae and Krokolithidae,and it is hypothesized that these three families of eggs correspond to troodontids,oviraptorids and crocodiloids,*** with egg fossils from Nanxiong Basin,Heyuan Basin and Ganzhou Basin highlights the similarity between these egg assemblages and those from Nanxiong *** egg fossils found in the Sanshui and the Dalangshan for-mations enrich the known faunal types in the research area and facilitate further studies on the diversity of Late Cretaceous vertebrate assemblages in the Sanshui Basin.

关键词： Prismatoolithidae Elongatoolithidae Krokolithidae Sanshui Formation Dalangshan Formation Upper Cretaceous

Tunable Anisotropic Lattice Thermal Conductivity in One-Dimensional Superlattices from Molecular Dynamics Simulations

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Journal of Thermal Science 2022年第4期31卷 1068-1075页

作者： w.ng Xiuqi AN Meng MA weigang ZHAng xing Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China College of Mechanical and Electrical Engineering Shaanxi University of Science and TechnologyXi'an 710021China

Engineering nanostructured superlattices provides an effective solution toward the realization of high-performance thermoelectric device and thermal management materials,where the anisotropic thermal conductivity is critical for designing orientation-dependent thermal ***,the lattice thermal conductivity anisotropy of Al/Ag superlattices as one typical example of superlattice materials is investigated utilizing non-equilibrium molecular dynamics *** cross-plane and in-plane lattice thermal conductivities of one-dimensional superlattices are in the ranges of 0.5–3.2 w/(m·K)and 1.8–5.1 w/(m·K)at different period lengths,respectively,both of which are smaller than those of bulk *** specifically,the cross-plane lattice thermal conductivity of superlattices increases with the period length,while the in-plane phonon thermal conductivity first increases and then trends to convergence,resulting in the non-monotonic thermal anisotropy *** further reveal the microscopic phonon transport mechanism,the interfacial phonon thermal resistance,density of states and spectral phonon transmission coefficient including anharmonic phonon properties under different period lengths are *** results can be helpful for understanding phonon transport in low-dimensional materials and provide guidance for optimizing the thermal conductivity anisotropy of superlattice materials in the application ranging from thermoelectric devices to thermal management in micro/nano systems.

关键词： anisotropic thermal conductivity superlattices phonon transport molecular dynamical simulations

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矩形周期性扩缩微通道内沸腾流动与传热

过程工程学报 2024年第7期24卷 793-804页

作者：邢谷雨袁俊飞王林江河冯梓城王梦轩河南科技大学建筑能源与热科学技术研究所河南洛阳471023

为了探究矩形周期性扩缩微通道内沸腾流动与传热特性,建立了不同尺寸的矩形周期性扩缩微通道,使用去离子水作为工作流体,在入口速度为0.2m/s,热流密度为50w/cm^(2)的条件下进行数值模拟。结果表明,矩形周期性扩缩微通道中存在扩大和缩... 详细信息

为了探究矩形周期性扩缩微通道内沸腾流动与传热特性,建立了不同尺寸的矩形周期性扩缩微通道,使用去离子水作为工作流体,在入口速度为0.2m/s,热流密度为50w/cm^(2)的条件下进行数值模拟。结果表明,矩形周期性扩缩微通道中存在扩大和缩小的截面结构,微通道中的扩大部分提供了成核位点,有利于气泡成核且增大换热面积。随着扩缩结构的周期性频率增加,微通道中空化和沸腾耦合传热越剧烈,通道的中下游区域仍存在着较多小气泡,通道沿程小气泡数量增多,含气率增加,传热性能不断提高,并且微通道沿程壁面最高温度逐渐降低,通道沿程温度分布更加均匀。矩形周期性扩缩微通道减少了气泡与壁面的接触面积,减少了两相摩擦压降,但是微通道中扩大和收缩部分增加了通道中的流动阻力,周期性扩缩微通道中的压降随着结构参数γ增大呈增大趋势。同时微通道中流动传热的综合性能随扩缩通道变化频率增加呈现先增大后减小的趋势,当结构参数γ=0.2时,矩形周期性扩缩微通道的综合性能最好,比矩形直微通道提升了34%。

关键词：矩形周期性扩缩微通道空化沸腾耦合数值模拟强化换热

Greedy nonlinear autoregression for multifidelity computer models at different scales

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能源与人工智能(英文) 2020年第1期1卷 117-130页

作者： w.xing M.Razi R.M.Kirby K.Sun A.A.Shah School of Energy and Power Engineering Chongqing University174 ShazhengjieShapingbaChongqing 400044China Scientific Computing and Imaging Institute University of Utah72 S Central Campus DriveRoom 3750 Salt Lake CityUT 84112United States

Although the popular multi-fidelity surrogate models,stochastic collocation and nonlinear autoregression have been applied successfully to multiple benchmark problems in different areas of science and engineering,they have certain *** propose a uniform Bayesian framework that connects these two methods allow.ng us to combine the strengths of *** this end,we introduce Greedy-NAR,a nonlinear Bayesian autoregressive model that can handle complex between-fidelity correlations and involves a sequential construction that allows for significant improvements in performance given a limited computational *** proposed enhanced nonlinear autoregressive method is applied to three benchmark problems that are typical of energy applications,namely molecular dynamics and computational fluid *** results indicate an increase in both prediction stability and accuracy when compared to those of the standard multi-fidelity autoregression *** results also reveal the advantages over the stochastic collocation approach in terms of accuracy and computational *** speaking,the proposed enhancement provides a straightforward and easily implemented approach for boosting the accuracy and efficiency of concatenated structure multi-fidelity simulation methods,e.g.,the nonlinear autoregressive model,with a negligible additional computational cost.

关键词： Multi-fidelity models Autoregressive Gaussian processes Deep Gaussian processes Surrogate models Molecular dynamics Computational fluid dynamics

Phase thermal stability and mechanical properties analyses of(Cr,Fe,V)–(Ta,w)multiple-based elemental system using a compositional gradient film

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International Journal of Minerals,Metallurgy and Materials 2020年第10期27卷 1379-1387页

作者： Qiu-wei xing Jiang Ma Yong Zhang Beijing Advanced Innovation Center of Materials Genome Engineering State Key Laboratory of Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics Engineering College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China

High-entropy alloys(HEAs)generally possess complex component combinations and abnormal *** traditional methods of investigating these alloys are becoming increasingly inefficient because of the unpredictable phase transformation and the combination of many *** development of compositionally complex materials such as HEAs requires high-throughput experimental methods,which involves preparing many samples in a short *** we apply the high-throughput method to investigate the phase evolution and mechanical properties of novel HEA film with the compositional gradient of(Cr,Fe,V)-(Ta,w).First,we deposited the compositional gradient film by ***,the mechanical properties and thermal stability of the(Cr0.33Fe0.33V0.33)x(Ta0.5w0.5)100−x(x=13-82)multiplebased-elemental(MBE)alloys were *** the deposited wafer was annealed at 600℃for 0.5 h,the initial amorphous phase was transformed into a body-centered cubic(bcc)structure phase when x=*** were observed on the film surface when x was 72 and ***,the highest hardness of as-deposited films was found when x=18,and the maximum hardness of annealed films was found when x=33.

关键词： high-throughput fabrication hard coating thermal resistance mechanical property phase stability high-entropy alloys

基于蜂窝仿生流场的质子交换膜燃料电池的性能研究及优化

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中南大学学报（自然科学版） 2024年第6期55卷 2106-2116页

作者：张凌云赵雷卢家鹏陈辉朱学军杨涛王诚杜星武汉科技大学省部共建耐火材料与冶金国家重点实验室湖北武汉430081 清华大学核能与新能源技术研究院北京100084 攀枝花学院生物与化学工程学院四川攀枝花617000

为了增强质子交换膜燃料电池(PEMFCs)内部燃料分布的均匀性与水管理能力,本文研究了一种新型的基于仿生结构的蜂窝仿生流场。首先,根据蜂窝结构特征,搭建出三维多相流非等温几何模型并确立PEMFC的数学模型;其次,采用计算流体动力学Fluen... 详细信息

为了增强质子交换膜燃料电池(PEMFCs)内部燃料分布的均匀性与水管理能力,本文研究了一种新型的基于仿生结构的蜂窝仿生流场。首先,根据蜂窝结构特征,搭建出三维多相流非等温几何模型并确立PEMFC的数学模型;其次,采用计算流体动力学Fluent软件对模型进行无关性与有效性验证,并对蜂窝仿生流场和常规平行流场的电池性能和燃料分布进行了模拟分析;最后,对比极化性能、气体流速分布、燃料与液态水组分浓度和电流密度分布,验证了蜂窝仿生流场设计的有效性。研究结果表明:采用蜂窝仿生流场的电池峰值功率密度比常规平行流场高15.6%,其内部水管理能力和燃料分布均匀性均强于平行流场;左端进气的蜂窝仿生流场比采用上端进气的蜂窝仿生流场在气体通路内具有更均匀的气体压力,可有效避免流道内产生局部涡流,其峰值功率密度可以达到0.3933 w/cm2。

关键词：质子交换膜燃料电池蜂窝仿生流场压降水管理

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37kV环氧树脂干式变压器设计与分析

机械设计与制造 2024年第5期399卷 249-252页

作者：田兴国刁燕苗虹张根莱四川大学机械工程学院四川成都610065 四川大学电气工程学院四川成都610065

根据干式变压器损耗和绝缘等级等要求,提出一种绕组各层匝数非均匀分布的新型37 kV环氧树脂干式变压器结构。该新型结构铁芯采用长圆形截面45°全斜五步进错位搭接结构;低压绕组共四层,内三层各一匝铜箔,第四层三匝铜箔;高压绕组共两层... 详细信息

根据干式变压器损耗和绝缘等级等要求,提出一种绕组各层匝数非均匀分布的新型37 kV环氧树脂干式变压器结构。该新型结构铁芯采用长圆形截面45°全斜五步进错位搭接结构;低压绕组共四层,内三层各一匝铜箔,第四层三匝铜箔;高压绕组共两层,每层12段。采用ANSYS Maxwell和ANSYS Fluent分别对干式变压器进行电磁场、温度场的仿真分析,得到干式变压器铁损曲线和温度分布云图。仿真结果表明干式变压器的空载损耗为4.5561kw,在室温、额定工况不开风机运行时温升为95K,以15%的过载系数在室温开风机运行时温升为87K,经验证该结构完全满足空载损耗8 000w和F级绝缘等级的要求。

关键词：干式变压器电磁场损耗温度场温升