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Effect of annealing temperature on magnetic properties of a sintered Nd-Fe-B magnet after grain boundary diffusion with Dy_(70)Cu_(30) alloy

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Journal of Rare Earths 2024年第1期42卷 116-120,I0004页

作者： Ruipeng Qian yuxuan Ma Fugang Chen Hui sun Yong Zhao Yunlong Chen School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003China School of Energy and Power Engineering Jiangsu University of Science and TechnologyZhenjiang212003China

Grain boundary diffusion process(GBDP)has been developed as an effective approach to increase the coercivity of sintered Nd-Fe-B magnets by regulating the compositions and phase distributions near grain boundaries.This work aims to explore how to select the optimum annealing temperature after GBDP.In this work GBDP was performed on a sintered Nd-Fe-B magnet using Dy_(70)Cu_(30) alloy.After GBDP the low eutectic temperature of the grain boundary phases decreases from the initial 492 to 451℃.The magnetic property dependent on different annealing temperatures near the low eutectic temperature was studied.The magnetic properties,especially the squareness factor of demagnetization curve show a strong dependence on the annealing temperature.After GBDP the optimal magnetic properties can be obtained after annealing just above the low eutectic temperature of the grain boundary phases.The mechanism is discussed based on the microstructure analysis.

关键词： Nd-Fe-B magnet Grain boundary diffusion Annealing Dy_(70)Cu_(30)alloy Rare earths

Unravelling the anisotropic light-matter interaction in strainengineered trihalide MoCl_(3)

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Nano Research 2024年第4期17卷 2981-2987页

作者： yuxuan sun Ziang Liu Zeya Li Feng Qin Junwei Huang Caiyu Qiu Hongtao Yuan National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210000China

Layered trihalides exhibit distinctive band structures and physical properties due to the sixfold coordinated 3d or 4d transition metal site and partially occupied d orbitals,holding great potential in condensed matter physics and advanced electronic applications.Prior research focused on trihalides with highly symmetric honeycomb-like structures,such as CrI3 andα-RuCl_(3),while the role of crystal anisotropy in trihalides remains elusive.In particular,the trihalide MoCl_(3) manifests strong in-plane crystal anisotropy with the largest difference in Mo–Mo interatomic distances.Research on such material is imperative to address the lack of investigations on the effect of anisotropy on the properties of trihalides.Herein,we demonstrated the anisotropy of MoCl_(3) through polarized Raman spectroscopy and further tuned the phonon frequency via strain engineering.We showed the Raman intensity exhibits twofold symmetry under parallel configuration and fourfold symmetry under perpendicular configuration with changing the polarization angle of incident light.Furthermore,we found that the phonon frequencies of MoCl_(3) decrease gradually and linearly with applying uniaxial tensile strain along the axis of symmetry in the MoCl_(3) crystal,while those frequencies increase with uniaxial tensile strain applied perpendicularly.Our results shed light on the manipulation of anisotropic light-matter interactions via strain engineering,and lay a foundation for further exploration of the anisotropy of trihalides and the modulation of their electronic,optical,and magnetic properties.

关键词： layered trihalide MoCl_(3) polarized Raman spectroscopy strain engineering anisotropy

An alternative approach to improve the compatibility of PCE in cement paste blend with coal gangue powder

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Waste Disposal and Sustainable Energy 2024年第1期6卷 139-150页

作者： Zonglin Xie yuxuan Li Dahui sun Yi Tian Jinyuan Hu Qiang Yuan Zheng Chen School of Civil Engineering Central South UniversityChangshaChina China Railway NO.9 Group CO. LTDShenyangChina National Engineering Research Center for High-Speed Railway Construction Technology ChangshaChina Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi UniversityNanningChina

Coal gangue(CG)is an environmental waste that faces an urgent demand for disposal in China.The utilization of CG in construction materials has broad application prospects and gained increasing interest.However,the poor compatibility of polycarboxylate superplasticizer(PCE)with CG powder hinders its efficiency in a wide range of applications.Here,this paper attempts to improve the compatibility of PCE with CG powder in cement paste based on the regulation of aggregation and the adsorption behavior of PCE.Dynamic light scattering(DLS)and fluorescence spectroscopy tests were carried out to understand the improved mechanism.The results indicated that the addition of CG powder increases the ionic strengths of the cement liquid phase,which makes PCE tend to aggregate at a lower concentration compared with no CG powder introduction.Adding(CH_(3)COO)_(2)Cu is beneficial for enhancing the workability of cement paste by reducing PCE aggregation while maintaining the compressive strength of cement specimens.Therefore,(CH_(3)COO)_(2)Cu extra addition can be regarded as an effective and sustainable way to improve the workability of cement paste with CG powder.

关键词： Coal gangue powder Polycarboxylate superplasticizer Compatibility Aggregation

Asymmetrically coordinated single atom Cu catalyst with unsaturated C-Cu-N structure for CO_(2) reduction to CO

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Nano Research 2024年第5期17卷 3911-3918页

作者： Zheng Liu yuxuan Liu Jingqiao Zhang Ting Cao Zhiyi sun Juzhe Liu Huishan Shang State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China SEPA Key Laboratory of Eco-Industry Chinese Research Academy of Environmental SciencesBeijing 100012China The Key Laboratory of Resources and Environmental System Optimization Ministry of EducationCollege of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China

Single atom catalysts(SACs)play a crucial role in energy catalysis due to their distinct coordination environment and high atomic utilization efficiency.This study focuses on the synthesis of a monatomic Cu catalyst with Cu-N1C1 coordination anchored to N-doped Ti_(3)C_(2)T_(x) MXene(Cu SA@N-Ti_(3)C_(2)T_(x))to achieve efficient reduction of CO_(2) to CO.Detailed characterization,including morphology and multispectral analysis,confirmed the uniform distribution of asymmetrically coordinated Cu atoms in unsaturated C-Cu-N bridge fragments on Ti_(3)C_(2)T_(x).The Cu SA@N-Ti_(3)C_(2)T_(x) catalyst exhibited an excellent CO selectivity with Faraday efficiency of 97.4%at-0.58 V vs.reversible hydrogen electrode(RHE)and satisfactory durability.The in situ X-ray absorption fine structure(XAFS)results confirmed that the carbon dioxide reduction reaction(CO_(2)RR)product distribution is mainly affected by potential-dependent valence change of Cu species.These findings highlight the extensive potential of tuning coordination structure of MXene-based single-atom catalysts for CO_(2) reduction reactions.

关键词： cooper single atom atomic regulation MXene Ti_(3)C_(2)T_(x) CO_(2)reduction

Early warning method for thermal runaway of lithium-ion batteries under thermal abuse condition based on online electrochemical impedance monitoring

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Journal of Energy Chemistry 2024年第5期92卷 74-86页

作者： yuxuan Li Lihua Jiang Ningjie Zhang Zesen Wei Wenxin Mei Qiangling Duan Jinhua sun Qingsong Wang State Key Laboratory of Fire Science University of Science and Technology of ChinaAnhui 230026HefeiChin

Early warning of thermal runaway(TR)of lithium-ion batteries(LIBs)is a significant challenge in current application scenarios.Timely and effective TR early warning technology is urgently required considering the current fire safety situation of LIBs.In this work,we report an early warning method of TR with online electrochemical impedance spectroscopy(EIS)monitoring,which overcomes the shortcomings of warning methods based on traditional signals such as temperature,gas,and pressure with obvious delay and high cost.With in-situ data acquisition through accelerating rate calorimeter(ARC)-EIS test,the crucial features of TR were extracted using the RReliefF algorithm.TR mechanisms corresponding to the features at specific frequencies were analyzed.Finally,a three-level warning strategy for single battery,series module,and parallel module was formulated,which can successfully send out an early warning signal ahead of the self-heating temperature of battery under thermal abuse condition.The technology can provide a reliable basis for the timely intervention of battery thermal management and fire protection systems and is expected to be applied to electric vehicles and energy storage devices to realize early warning and improve battery safety.

关键词： Online EIS measurement Lithium-ion batterysafety Multistage thermal runaway early warning Sensitivityanalysis

Non-invasive imaging of pathological scars using a portable handheld two-photon microscope

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Chinese Medical Journal 2024年第3期137卷 329-337页

作者： Yang Han yuxuan sun Feili Yang Qingwu Liu Wenmin Fei Wenzhuo Qiu Junjie Wang Linshuang Li Xuejun Zhang Aimin Wang Yong Cui Graduate School Chinese Academy of Medical SciencesPeking Union Medical CollegeBeijing 100730China Department of Dermatology China-Japan Friendship HospitalBeijing 100029China College of Engineering Peking UniversityBeijing 100871China School of Chemical Biology and Biotechnology State Key Laboratory of Chemical OncogenomicsPeking University Shenzhen Graduate SchoolShenzhenGuangdong 518055China Department of Dermatology The First Affiliated Hospital of Nanchang UniversityNanchangJiangxi 330006China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China College of Future Technology Peking UniversityBeijing 100871China Beijing Transcend Vivoscope Biotech Beijing 100085China Department of Dermatology The First Affiliated Hospital of Anhui Medical UniversityHefeiAnhui 230001China Institute of Dermatology Anhui Medical UniversityHefeiAnhui 230001China School of Electronics Peking UniversityBeijing 100871China

Background:Pathological scars are a disorder that can lead to various cosmetic,psychological,and functional problems,and no effective assessment methods are currently available.Assessment and treatment of pathological scars are based on cutaneous manifestations.A two-photon microscope(TPM)with the potential for real-time non-invasive assessment may help determine the under-surface pathophysiological conditions in vivo.This study used a portable handheld TPM to image epidermal cells and dermal collagen structures in pathological scars and normal skin in vivo to evaluate the effectiveness of treatment in scar patients.Methods:Fifteen patients with pathological scars and three healthy controls were recruited.Imaging was performed using a portable handheld TPM.Five indexes were extracted from two dimensional(2D)and three dimensional(3D)perspectives,including collagen depth,dermo-epidermal junction(DEJ)contour ratio,thickness,orientation,and occupation(proportion of collagen fibers in the field of view)of collagen.Two depth-dependent indexes were computed through the 3D second harmonic generation image and three morphology-related indexes from the 2D images.We assessed index differences between scar and normal skin and changes before and after treatment.Results:Pathological scars and normal skin differed markedly regarding the epidermal morphological structure and the spectral characteristics of collagen fibers.Five indexes were employed to distinguish between normal skin and scar tissue.Statistically significant differences were found in average depth(t=9.917,P<0.001),thickness(t=4.037,P<0.001),occupation(t=2.169,P<0.050),orientation of collagen(t=3.669,P<0.001),and the DEJ contour ratio(t=5.105,P<0.001).Conclusions:Use of portable handheld TPM can distinguish collagen from skin tissues;thus,it is more suitable for scar imaging than reflectance confocal microscopy.Thus,a TPM may be an auxiliary tool for scar treatment selection and assessing treatment efficacy.

关键词： Scars Two-photon microscope Two-photon excitation fluorescence Second harmonic generation microscopy

Development of a Suitable,Cultural,and Life-Oriented Kindergarten Curriculum

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Journal of Contemporary Educational Research 2024年第1期8卷 88-95页

作者： yuxuan sun School of Educational Science Jiangsu Normal UniversityXuzhou 221116Jiangsu ProvinceChina

The technological revolution and the explosion of information have created a diverse world.More and more so-called advanced cultures are entering kindergartens,prompting us to think about how to correctly develop the existing local cultures in the cultural context,while simultaneously accepting and absorbing the appropriate parts of foreign cultures.It is also necessary to maintain a balance between diversity and localization to prevent kindergartens from becoming a“colony”of foreign cultures.The development of suitable,cultural,and life-oriented kindergarten curricula from different perspectives is the focus of such a balance.Only in this way can kindergartens truly fulfill their educational functions and provide a vibrant and colorful environment for children.

关键词： Kindergarten curriculum Suitability Culture Life-oriented

In situ reconstruction induced oxygen-deficient multiphase Cu based species hybridized with Ni single atoms as tandem platform for CO_(2) electroreduction

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Nano Research 2024年第5期17卷 3888-3894页

作者： Juzhe Liu Yuheng Wang Pengpeng Mo Feng Yang Kaiqi Jiang Zhixiang Cheng yuxuan Liu Zhiyi sun Zheng Liu Yimei Zhang Wenxing Chen The Key Laboratory of Resources and Environmental System Optimization Ministry of EducationCollege of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China Energy&Catalysis Center School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China SEPA Key Laboratory of Eco-Industry Chinese Research Academy of Environmental SciencesBeijing 100012China

Tandem catalysis,capable of decoupling individual steps,provides a feasible way to build a high-efficiency CO_(2) electro-conversion system for multicarbons(C_(2+)).The construction of electrocatalytic materials is one of focusing issues.Herein,we fabricated a single atom involved multivalent oxide-derived Cu composite material and found it inclined to reconstruct into oxygen-deficient multiphase Cu based species hybridized with monatomic Ni on N doped C matrix.In this prototype,rapid CO generation and C-C coupling are successively achieved on NiN4 sites and surface amorphized Cu species with defects,resembling a micro-production line.In this way,the in situ formed tandem catalyst exhibited a high Faradaic efficiency(FE)of~78%for C_(2+)products along with satisfactory durability over 50 h.Particularly,the reconstruction-induced amorphous layer with abundant asymmetric sites should be favorable to improve the ethanol selectivity(FE:63%),which is about 10 times higher than that of the non-tandem Cu-based contrast material.This work offers a new approach for manipulating tandem catalyst systems towards enhancing C_(2+)products.

关键词： tandem catalysis single atom reconstruction amorphous CO_(2)reduction reaction

从整合到消解:设备管线空间分布的设计策略演进研究

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建筑学报 2024年第2期 9-15页

作者：孙宇璇重庆大学建筑城规学院重庆400030 山地城镇建设与新技术教育部重点实验室重庆400030

针对设备系统愈发复杂的现状,基于历史与设计的双重视角,探索以空调风管为主的设备管线空间分布设计策略的演进,将该过程归纳为3个阶段:初入建筑的独立阶段、结构协调的整合阶段、整体布置的消解阶段。从整合到消解的演进,体现出对设备... 详细信息

针对设备系统愈发复杂的现状,基于历史与设计的双重视角,探索以空调风管为主的设备管线空间分布设计策略的演进,将该过程归纳为3个阶段:初入建筑的独立阶段、结构协调的整合阶段、整体布置的消解阶段。从整合到消解的演进,体现出对设备系统的关注从功能构造到能源可持续发展的转变。揭示驱动演进的因素和未来发展趋势,旨在深化对环境调控所涉及技术议题的理解,推动建筑设计实践向绿色低碳方向迈进。

关键词：建筑系统空调管线设计策略热活性楼板