检索结果-南通市图书馆

Journal of Magnesium and Alloys 2024年第9期12卷 3574-3588页

作者： Jiawei Sun Dehua Ding Wencai Liu Guohua Wu Hongjie Liu Guangling Wei Hezhou Liu National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

A novel Mg^(-1)0Li-3Al(wt.%,LA103)matrix composite reinforced by ex situ micron TiB_(2) particles was developed in the present *** ball milling and cold pressing pretreatment of the reinforcements made it feasible to prepare this material under stir casting conditions with good *** microstructure and mechanical properties of the composites prepared by different pretreatment methods were analyzed in *** TiB_(2) particles in the Al-TiB_(2)/LA103 composite using the pretreatment process were uniformly distributed in the microstructure due to the formation of highly wettable core-shell units in the *** with the matrix alloys,the Al-TiB_(2)/LA103 composite exhibited effective strength and elastic modulus improvements while maintaining acceptable *** strengthening effect in the composites was mainly attributed to the strong grain refining effect of *** work shows a balance of high specific modulus(36.1 GPa·cm^(3)·g^(-1))and elongation(8.4%)with the conventional stir casting path,which is of considerable application value.

关键词： Mg-Li composite Stir casting Elastic modulus Microstructure Mechanical properties

Polymeric nanocomposites for electrocaloric refrigeration

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2023年第4期17卷 450-462页

作者： Yu CAI Qiang LI Feihong DU Jiawang FENG Donglin HAN Shanyu ZHENG Shihao YANG Yingjing ZHANG Binbin YU Junye SHI Xiaoshi QIAN State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai200240China Interdisciplinary Research Center Institute of Refrigeration and CryogenicsSchool of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China shanghai jiao tong university Zhongguancun Research Institute Liyang213300China

Electrocaloric refrigeration represents an alternative solid-state cooling technology that has the potential to reach the ultimate goal of achieving zero-global-warming potential,highly efficient refrigeration,and heat *** date,both polymeric and inorganic oxides have demonstrated giant electrocaloric effect as well as respective cooling *** both polymeric and inorganic oxides have been identified as promising cooling methods that are distinguishable from the traditional ones,they still pose many challenges to more practical *** an electrocaloric material point of view,electrocaloric nanocomposites may provide a solution to combine the beneficial effects of both organic and inorganic electrocaloric *** article reviews the recent advancements in polymer-based electrocaloric composites and the state-of-the-art cooling devices operating these *** a device point of view,it discusses the existing challenges and potential opportunities of electrocaloric nanocomposites.

关键词： nanocomposites electrocaloric refrigeration polymer

Multi-element B-site substituted perovskite ferroelectrics exhibit enhanced electrocaloric effect

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第4期66卷 1119-1128页

作者： DU FeiHong SONG ZhiWu XU YuTao HAN DongLin LI Qiang ZHENG ShanYu SHEN JiaHe QIAN XiaoShi Interdisciplinary Research Centre School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Zhejiang Research Institute of Chemical Industry Hangzhou 310023China

Electrocaloric(EC)refrigeration holds the promise to achieve next-generation refrigeration technology that can be efficiently powered by ***_(3)(BT)-based ferroelectric materials are attractive owing to their environmentally benign compositions,large polarization,and existing manufacturing method for multilayer ceramic capacitors(MLCC),which have stimulated intensive research efforts on these ***,we report an enhanced electrocaloric effect(ECE)and the refrigeration capacity of multi-element B-site substituted BT-based *** compositions of the proposed Ba(Hf_(x)Sn_(x)Zr_(y))-Ti_(1-2x-y)O_(3)(BHSZT)ceramics were selected by fine-tuning each substituent against Titanium ions Ti^(4+),aiming to their respective morphotropic phase boundary(MPB).The BHSZT exhibited an ECE that is greater than that of the single-element substituted BaTiO_(3) ceramics by at least 50%,reaching an adiabatic temperature change of above 1.7 K under 40 kV/***,the operating temperature window of the BHSZT ceramics is observed to cover the room temperature,which is a critical feature that allows the device implementation in our daily *** multi-element substitution improved the overall ECE performances,providing a high degree of freedom for polar reorientation and hence the large polar entropy that could be utilized by the external electric field.

关键词： ferroelectrics electrocalorics Ceramics

Adsorption of lead on multi-walled carbon nanotubes with different outer diameters and oxygen contents: Kinetics, isotherms and thermodynamics

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第1期25卷 195-203页

作者： Fei Yu Yanqing Wu Jie Ma Chi Zhang School of Environmental Science and Engineering Shanghai Jiao Tong University State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji University

The effects of different outer diameters and surface oxygen contents on the adsorption of heavy metals onto six types of multi-walled carbon nanotubes （MWCNTs） were investigated in an aqueous solution and lead was chosen as a model metal ion. The results indicated that the percentage removal and adsorption capacity of lead remarkably increased with decreasing outer diameter due to larger specific surface area （SSA）. The SSA-normalized maximum adsorption capacity （qJSSA） and SSA-normalized adsorption coefficient （KdSSA） were strongly positively correlated with surface oxygen content, implying that lead adsorption onto MWCNTs significantly increases with the rise of oxygen content and decreases with decreasing SSA. The calculated thermodynamic parameters indicated that adsorption of lead on MWCNTs was endothermic and spontaneous. When the oxygen content of MWCNTs increased from 2.0% to 5.9%, the standard free energy （AGt） became more negative, which implied that the oxygenated functional groups increased the adsorption affinity of MWCNTs for lead. Through calculation of enthalpy （△H0）, AGO and free energy of adsorption （Ea）, lead adsorption onto MWCNTs was recognized as a chemisorption process. The chemical interaction between lead and the phenolic groups of MWCNTs could be one of the main adsorption mechanisms due to highly positive correlations between the phenolic groups and Kd/SSA or qm/SSA.

关键词： adsorption lead multi-walled carbon nanotube diameter surface oxygen content

High electrocaloric effect in barium titanate-sodium niobate ceramics with core-shell grain assembly

在线全文

学校读者我要写书评

暂无评论

Journal of Materiomics 2020年第3期6卷 618-627页

作者： Chao Zhang Quanpei Du Wenru Li Dong Su Meng Shen Xiaoshi Qian Bing Li Haibo Zhang Shenglin Jiang Guangzu Zhang School of Optical and Electronic Information Engineering Research Center for Functional Ceramics MOE and Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan430074China Institute of Refrigeration and Cryogenics School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China Shenyang National Laboratory(SYNL)for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan430074China Shenzhen Huazhong university of Science and Technology Research Institute Shenzhen518057China

Electrocaloric effect(ECE)is promising in realizing solid-state cooling as an alternative to the conventional refrigeration with environmentally harmful coolant and low *** ECE in lead-free ferroelectric ceramics is highly desirable for the EC *** this work,different from the researches that tune the ECE by conventional compositional design or external stress engineering,we fabricated the(1-x)BaTiO_(3)-xNaNbO_(3)(BTO-xNN)lead-free ceramics with a core-shell grain structure arising from the inhomogeneous stoichiometry of element distribution,leading to the internal compressing stress in the *** is interesting that the phase transition behavior,including the phase transition temperature and the diffusion property,is regulated by the core-shell grain structure induced internal stress,which can be capitalized on for the favorable *** with 0.02 NN,a high ECE,*** temperature change(ΔT)of 3.6 K and isothermal entropy change(ΔS)of 4.5 J kg^(-1) K^(-1),is attained in the BTO *** the internal stress further increases with more NN,the BTO-0.06NN exhibits an extremely stable ECE with a variety rate below ±4% in a wide temperature range from 300 K to 360 *** work provides a novel approach to explore pronounced ECE in lead-free ferroelectrics for eco-friendly refrigeration.

关键词： Electrocaloric effect Core-shell structure Lead-free ceramics Internal stress High temperature stability

MOD-Net:A Machine Learning Approach via Model-Operator-Data Network for Solving PDEs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2022年第7期32卷 299-335页

作者： Lulu Zhang Tao Luo Yaoyu Zhang Weinan E Zhi-Qin John Xu Zheng Ma Institute of Natural Sciences and School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai200240China School of Mathematical Sciences and Institute of Natural Sciences Shanghai Jiao Tong UniversityCMA-ShanghaiShanghai200240China MOE-LSC and Qing Yuan Research Institute Shanghai Jiao Tong UniversityShanghai200240China shanghai Center for Brain Science and Brain-Inspired Technology Shanghai200031China School of Mathematical Sciences Peking UniversityBeijing100871China AI for Science Institute Beijing100080China

In this paper,we propose a machine learning approach via model-operatordata network(MOD-Net)for solving PDEs.A MOD-Net is driven by a model to solve PDEs based on operator representationwith regularization *** linear PDEs,we use a DNN to parameterize the Green’s function and obtain the neural operator to approximate the solution according to the Green’s *** train the DNN,the empirical risk consists of the mean squared loss with the least square formulation or the variational formulation of the governing equation and boundary *** complicated problems,the empirical risk also includes a fewlabels,which are computed on coarse grid points with cheap computation cost and significantly improves the model ***,the labeled dataset works as a regularization in addition to the model *** MOD-Net solves a family of PDEs rather than a specific one and is much more efficient than original neural operator because few expensive labels are *** numerically show MOD-Net is very efficient in solving Poisson equation and one-dimensional radiative transfer *** nonlinear PDEs,the nonlinear MOD-Net can be similarly used as an ansatz for solving nonlinear PDEs,exemplified by solving several nonlinear PDE problems,such as the Burgers equation.

关键词： Deep neural network radiative transfer equation Green’s method neural operator