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Temperature-Dependent Rheological Behaviors of Binary Eutectic Mixtures of Sugar Alcohols for Latent Heat Storage:A Comparative Study with Pure Sugar Alcohols

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Journal of Thermal Science 2021年第6期30卷 2002-2014页

作者： SHAO Xuefeng YANG Sheng chen chenlin FAN Liwu YU Zitao Institute of Thermal Science and Power Systems School of Energy EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

The temperature-dependent rheological behaviors of five selected binary eutectic mixture sugar alcohols,with great potential for latent heat storage in the range of 353.15 K to 523.15 K,were *** was found that the rheological behaviors of the mixture sugar alcohols depend on those of the pure compounds as well as their molar *** two mixtures of xylitol(75 mol%)+erythritol and erythritol(84 mol%)+d-mannitol behave like pseudoplastic fluids with typical non-Newtonian shear-thinning behaviors,as indicated by the power law index of 0.99(<1).The mixture of d-mannitol(70 mol%)+d-dulcitol is a nonlinear Bingham fluid,exhibiting a slight yield stress(0.001 Pa to 0.01 Pa)at low shear *** rest two mixtures containing the cyclic-structured inositol behave like Herschel-Bulkley *** infinite shear viscosities of the eutectic mixtures over the entire temperature range appear to be higher than those of their respective pure compounds,except for *** mixture of xylitol(75 mol%)+erythritol at its melting point shows higher dynamic viscosity of about 0.546 Pa·s than the values of about 0.396 Pa·s and 0.035 Pa·s for xylitol and erythritol,*** addition,the activation energies of viscous flow of the mixtures,as determined by fitting the dynamic viscosity-temperature curves using the Arrhenius model,also exhibit higher values than those of their pure *** activation energy of viscous flow of the mixture xylitol(75 mol%)+erythritol was determined to be about 92400 J/mol in the supercooled liquid state,while the supercooled liquid xylitol and erythritol have much lower values of 83500 J/mol and 51900 J/mol,*** the increased dynamic viscosities and activation energies of viscous flow can result in deteriorated crystallization performance during latent heat retrieval.

关键词： binary eutectic mixture dynamic viscosity phase change material rheological behavior sugar alcohol latent heat storage

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新型零碳氨燃料的燃烧特性研究进展

华中科技大学学报（自然科学版） 2022年第7期50卷 24-40,78页

作者：王智化余作超陈晨霖何勇朱燕群浙江大学能源清洁利用国家重点实验室浙江杭州310027

介绍了国内外对氨燃烧特性的最新研究成果,分析了氢气、合成气、甲烷等各种燃料掺混对氨火焰在点火延迟时间、层流火焰速度和NO_(x)排放特性方面的影响,阐述了近年来包含NH_(3)组分的化学反应动力学机理模型的研究现状,并总结了现阶段... 详细信息

介绍了国内外对氨燃烧特性的最新研究成果,分析了氢气、合成气、甲烷等各种燃料掺混对氨火焰在点火延迟时间、层流火焰速度和NO_(x)排放特性方面的影响,阐述了近年来包含NH_(3)组分的化学反应动力学机理模型的研究现状,并总结了现阶段的氨燃烧的工业化应用探索,为之后的相关研究提供参考.氨作为新型零碳燃料替代传统化石能源燃烧供能是可行的,未来发展纯NH3、NH3与各种气液固燃料的掺混燃烧技术及低NO_(x)燃烧技术,最终有望在内燃机、燃气轮机、锅炉等动力装置中大规模使用.

关键词：氨燃料掺混燃烧点火延迟时间层流火焰速度 NO_(x)排放特性化学反应动力学机理

Meridional deflection of global eddy propagation derived from tandem altimetry: Mechanism and implication

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Science China Earth Sciences 2024年第3期67卷 811-825页

作者： Ge chen Xiaoyan chen Frontiers Science Center for Deep Ocean Multispheres and Earth System School of Marine TechnologyOcean University of ChinaQindao 266100China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQindao 266237China

A common view on meridional deflection of eddy propagation is poleward for cyclones and equatorward for anticyclones. This widely accepted polarity-sensitive pattern has been increasingly undermined given that it is systematically violated on both zonal and regional scales as recently reported. Here, we approach the problem by exploring these violations in terms of eddy effects of spatiotemporal geostrophy, thermal fading, and flow dragging, yielding the following main conclusions.(1) The polarity-dependent deflection discrepancy is a pseudo feature resulting from a biased fit to the normalized eddy tracks which are spatially asymmetric(though azimuthally symmetric) between the two signs;Instead, the primary pattern of eddy deflection appears to be geographically correlated and polarity independent.(2) Geostrophic adjustment plays a critical role in defining the meridional movement of an eddy. Specifically, a consistent poleward(equatorward) trajectory bending of spatially(temporally) ageostrophic eddies is observed irrespective of their polarity.(3) The mechanism of eddy deflection is also determined by its zonal propagation direction. Westward propagating eddies are substantially affected by thermal fading, while opposite ones by flow dragging. A realistic and comprehensive understanding of eddy deflection mechanisms serves as a significant contribution to the prediction of eddy trajectory, and the protection of ocean environment.

关键词： Mesoscale eddies Eddy propagation Eddy meridional deflection Satellite observation Geostrophic adjustment

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A refined representation method of the particle size distribution curve based on grading entropy

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Particuology 2024年第5期88卷 302-311页

作者： Xing Li Qun chen Zhaozhao Liu cheng Zhou chen Wang chen chen State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China

The particle size distribution(PSD)curve is an important expression of the basic properties of the *** characteristic parameters such as median particle size D_(50),effective particle size D_(10),and some combinations of characteristic parameters can only represent some points of the PSD curve,failing to represent all information of the PSD *** this paper,a fraction characteristic parameter F that could reflect the fraction size variation of the PSD curve was introduced based on grading *** a new presentation method of the A-B-F three parameters was proposed for a refined representation of the PSD *** was found that the newly constructed model not only better represents the differences in the width of PSD curves but also has a higher sensitivity than the A-B two-parameter model proposed by Lő*** PSD curves with similar distributions,the new presentation method has a higher degree of discrimination than that of the D_(50)-C_(u)-C_(c) three-parameter or the four-parameter combination G_(c) proposed by ***,the application of this new method in describing the spatial nonuniformity distribution of depositions and predicting the soil hydraulic conductivity was *** research results can provide a reference for the refined representation of PSD curves.

关键词： Grading entropy Particle size distribution curve Refined representation

基于改进声学有限元法的主变压器室噪声场计算

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中国电机工程学报 2024年第4期44卷 1662-1674,I0034页

作者：唐波刘思煜白晓春陈国庆蔡晨林湖北省输电线路工程技术研究中心(三峡大学) 湖北省宜昌市443002 三峡大学电气与新能源学院湖北省宜昌市443002 国网陕西省电力有限公司电力科学研究院陕西省西安市710100

传统声学有限元法(finite element method,FEM)难以准确表征温升效应引起的主变室大空间空气介质参数变化,导致温度场-声场耦合作用下变电站主变压器室噪声场计算误差过大。在声学FEM算法基础上,引入计算流体力学(computational fluid d... 详细信息

传统声学有限元法(finite element method,FEM)难以准确表征温升效应引起的主变室大空间空气介质参数变化,导致温度场-声场耦合作用下变电站主变压器室噪声场计算误差过大。在声学FEM算法基础上,引入计算流体力学(computational fluid dynamics,CFD),提取大空间主变室的复杂空间介质参量,并对波动积分方程进行改进,提出一种基于改进声学FEM的主变室内噪声场求解算法。首先,建立温度场影响下的主变室流变模型,采用CFD表征主变室大空间温度场离散空间介质参量;然后,基于流-声网格映射理论,将温度场离散空间介质参量与声音网格进行映射,建立修正大空间空气介质参数后的声学FEM积分方程;最后,基于常规Gauss数值积分法和引入Kirchhoff-Helmholtz方程,对修正声学FEM积分方程进行联合求解。该算法在西安110 kV昌明变电站1号主变室噪声场的求解分析中得到了成功应用,与实测值误差为2.168%。

关键词：户内变电站噪声场声学有限元法计算流体力学温–声耦合场

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Track correlation algorithm based on CNN-LSTM for swarm targets

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Journal of Systems Engineering and Electronics 2024年第2期35卷 417-429页

作者： chen Jinyang WANG Xuhua chen Xian Research Institute for National Defense Engineering Academy of Military SciencesLuoyang 471023China Information Engineering University Zhengzhou 450001China School of Computer Science and Technology Xidian UniversityXi’an 710071China

The rapid development of unmanned aerial vehicle(UAV) swarm, a new type of aerial threat target, has brought great pressure to the air defense early warning system. At present, most of the track correlation algorithms only use part of the target location, speed, and other information for *** this paper, the artificial neural network method is used to establish the corresponding intelligent track correlation model and method according to the characteristics of swarm ***, a route correlation method based on convolutional neural networks (CNN) and long short-term memory (LSTM)Neural network is designed. In this model, the CNN is used to extract the formation characteristics of UAV swarm and the spatial position characteristics of single UAV track in the formation,while the LSTM is used to extract the time characteristics of UAV swarm. Experimental results show that compared with the traditional algorithms, the algorithm based on CNN-LSTM neural network can make full use of multiple feature information of the target, and has better robustness and accuracy for swarm targets.

关键词： track correlation correlation accuracy rate swarm target convolutional neural network(CNN) long short-term memory(LSTM)neural network

Two-stage Planning Method for Energy Router Considering Its Optimal Operation in Distribution Networks

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 605-616页

作者： Meifu chen Mingchao Xia Qifang chen School of Electrical Engineering Beijing Jiaotong UniversityBeijing 100044China

An energy router can effectively optimize the network loss and power quality of distribution networks. The optimal configuration of the energy router is relatively complex because issues dynamically influence each other, such as the location of the energy router, optimal number and capacity of its ports, and building new distribution lines for the ports. Presently, there has been very few research studies on the practical problems for the energy router. In this paper, a planning model of an energy router combined with the distribution network is established, which fully exploits the active and reactive power control abilities of the energy router to optimize the operation of the grid. The configuration problem is decoupled into two stages. The upper layer determines the location of the energy router and the parameters of the candidate new distribution lines for the ports. The lower layer calculates the optimal configuration of the energy router by minimizing the total annual cost. Because of the same rated bus voltage in the distribution network, the existing structure of the energy router is changed to be more applicable for the distribution network, and then the power flow model of the energy router is also modified. Due to the nonlinearity of the model, the planning model is converted into a mixed-integer second-order cone model to solve efficiently. In addition, some core factors influencing the optimal scheme of the energy router are also analyzed in this paper. Simulation results show that the optimal scheme of the energy router can significantly improve the economic deployment of the energy router, and optimize the network loss and power quality of the distribution network.

关键词： Capacity allocation distribution network energy router optimal operation

Aerial target threat assessment based on gated recurrent unit and self-attention mechanism

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Journal of Systems Engineering and Electronics 2024年第2期35卷 361-373页

作者： chen chen QUAN Wei SHAO Zhuang School of Automation Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing 100081China

Aerial threat assessment is a crucial link in modern air combat, whose result counts a great deal for commanders to make decisions. With the consideration that the existing threat assessment methods have difficulties in dealing with high dimensional time series target data, a threat assessment method based on self-attention mechanism and gated recurrent unit(SAGRU) is proposed. Firstly, a threat feature system including air combat situations and capability features is established. Moreover, a data augmentation process based on fractional Fourier transform(FRFT) is applied to extract more valuable information from time series situation features. Furthermore, aiming to capture key characteristics of battlefield evolution, a bidirectional GRU and SA mechanisms are designed for enhanced ***, after the concatenation of the processed air combat situation and capability features, the target threat level will be predicted by fully connected neural layers and the softmax classifier. Finally, in order to validate this model, an air combat dataset generated by a combat simulation system is introduced for model training and testing. The comparison experiments show the proposed model has structural rationality and can perform threat assessment faster and more accurately than the other existing models based on deep learning.

关键词： target threat assessment gated recurrent unit(GRU) self-attention(SA) fractional Fourier transform(FRFT)

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氨煤掺混燃烧减碳方案经济性分析

燃烧科学与技术 2023年第6期29卷 667-675页

作者：张芮琳王智化陈晨霖何勇朱燕群岑可法浙江大学能源清洁利用国家重点实验室杭州310007

利用平准化电力成本的模型方法对掺氨燃烧技术的经济可行性进行了评估.对在大型燃煤电厂1000MW机组上应用掺氨燃烧技术和碳捕集与封存技术(CCS)两种减碳方案的经济竞争力进行了比较;并针对未来氨成本降低和碳价、煤价升高的趋势,比较了... 详细信息

利用平准化电力成本的模型方法对掺氨燃烧技术的经济可行性进行了评估.对在大型燃煤电厂1000MW机组上应用掺氨燃烧技术和碳捕集与封存技术(CCS)两种减碳方案的经济竞争力进行了比较;并针对未来氨成本降低和碳价、煤价升高的趋势,比较了氨煤混燃和纯煤燃烧两种情况的经济成本来进一步论证零碳氨替代燃料减碳方案的可行性.针对结果提出相关建议,弥补了当前关于氨燃料经济性评估方面研究的不足,论证了零碳氨燃料的市场推广价值.

关键词：氨煤共燃碳减排经济性分析