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Journal of Materiomics 2021年第4期7卷 858-868页

作者： xuemin yin Hejun Li Ruimei Yuan Yameng Jiao Jinhua Lu State Key Laboratory of Solidification Processing Shaanxi Province Key Laboratory of Fiber Reinforced Light Composite MaterialsCarbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an710072China

Rational construction of transitional metal oxides electrode materials with suitable structure and composition is an effective strategy of improving their electrochemical ***,novel MCo_(2)O_(4) hierarchical nanofibers(H-MCo_(2)O_(4)NFs,M¼Ni,Co and Mn)were fabricated by a multi-step selftemplating method using electrospun nanofibers as *** from the unique structure,such as numerous of vertically interlinked nanosheets on the surface and 1D interwoven nanofibers networks,the obtained HeNiCo_(2)O_(4)NFs electrode exhibits a high specific capacitance of 1750 F g1(At a current density of 0.5 A g1),good rate capability(Capacitance retention of 70%at 20 A g1),and outstanding cycling stability(Capacitance retention of 92%after 6000 cycles).Moreover,the solid-state hybrid supercapacitor assembled by HeNiCo_(2)O_(4)NFs and activated carbon(AC),delivers a high energy density of 38.4 Wh kg1 at a power density of 800 W kg1,and excellent cycling ***,the HeNiCo_(2)O_(4)NFs is a promising candidate material for supercapacitors electrode and this self-templating method in this work also provides a new path for the preparation of one-dimensional hierarchical metallic oxides.

关键词： Electrospinning Supercapacitor NiCo_(2)O_(4) Hierarchical nanofibers Self-templating method

Free-standing SnNb_(2)O_(6)@CSN film as flexible anode for high performance sodium-ion batteries

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Chinese Chemical Letters 2023年第7期34卷 284-288页

作者： xuemin yin Tao Liu Xiuping yin Xiaochen Feng Yiming Liu Qinhao Shi Xingli Zou Yufeng Zhao Institute for Sustainable Energy and College of Sciences Shanghai UniversityShanghai 200444China Department of Materials Science and Engineering Shanghai UniversityShanghai 200072China

Free-standing electrodes are promising candidates for flexible rechargeable batteries, toward the application of flexible energy storage devices, due to their merits of additive-free, lightweight, and high energy density. Herein, we report a free-standing SnNb_(2)O_(6)@CSN flexible film with SnNb_(2)O_(6) encapsulated in 3D carbon skeleton nanofibers by electrospinning and carbonization processes as flexible anode for sodium-ion batteries(SIBs). The 3D carbon skeleton nanofibers serve as ion/electron transport pathway to improve the electrochemical reaction kinetics and meanwhile alleviate the volume changes of SnNb_(2)O_(6) during charge-discharge processes. The as-constructed half-cell(SnNb_(2)O_(6)@CSN‖Na) exhibits excellent cycling stability of 99.2 m Ah/g at 0.5 A/g after 950 cycles(coulombic efficiency of ~100%) and a high rate performance of 108.6 mAh/g at 10 A/g. In addition, the pouch cell can light up the LEDs at different bending angles(0°, 90°, 180°). This research shows a promising anode material for flexible energy storage electronics.

关键词： Free-standing SnNb_(2)O_(6)@CSN Anode Sodium-ion batteries Flexible material

Si_(3)N_(4)nanowires@pyrolytic carbon nanolayers coupled withhydroxyapatite nanosheets as reinforcement for carbon matrixcomposites with boosting mechanical and friction properties

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Journal of Materiomics 2023年第1期9卷 197-205页

作者： Lina Sun Leilei Zhang xuemin yin Yeye Liu Yao Guo Hongchao Sheng Xianghui Hou State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Fiber Reinforced Light Composite MaterialsNorthwestern PolytechnicalUniversityXi'an710072China Department of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003China Faculty of Engineering The University of NottinghamUniversity ParkNottinghamNG72RDUnited Kingdom

Extensive attention has been drawn to the development of carbon-matrix composites for application in the aerospace and military industry,where a combination of high mechanical strength and excellent frictional properties are ***,carbon-matrix composites reinforced by Si_(3)N_(4)nanowires@pyrolytic carbon nanolayers(Si_(3)N_(4nws)@PyCnls)coupled with hydroxyapatite nanosheets is *** Si_(3)N_(4nws)@PyCnls(SP)with coaxial structure could increase the surface roughness of Si_(3)N_(4nws)and promote the stress transfer to the carbon matrix,whereas the porous hydroxyapatite nanosheets favor the infiltration of the carbon matrix and promote the interfacial bonding between the SP and carbon *** carbon matrix composites reinforced by SP coupled with hydroxyapatite nanosheets(Si_(3)N_(4nws)@PyCnls-HA-C)exhibit excellent mechanical *** with the conventional Si_(3)N_(4nws)reinforced carbon composites,Si_(3)N_(4nws)@PyCnls-HA-C(SPHC)have 162%and 249%improvement in flexural strength and elastic modulus,***,the friction coefficient and wear rate decreased by 53%and 23%,*** study provides a co-reinforcement strategy generated by SP coupled with hydroxyapatite nanosheets for effective improvement of mechanical and frictional properties of carbon matrix composites that are used for aerospace and military industry applications.

关键词： Silicon nitride nanowire Coaxial structure Hydroxyapatite nanosheet Mechanical strength Friction performance Carbon matrix composites

Microstructure and evolution of hafnium carbide whiskers via polymer-derived ceramics:A novel formation mechanism

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Journal of Advanced Ceramics 2023年第3期12卷 578-586页

作者： Yanqin Fu Yulei Zhang Hao Yan Jinhua Li xuemin yin Jia Sun Qiangang Fu Ralf Riedel Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials Northwestern Polytechnical UniversityXi’an 710072China School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China Institut für Materialwissenschaft Technische Universität DarmstadtDarmstadt D-64287Germany

Polymer-derived ultra-high-temperature ceramic(UHTC)nanocomposites have attracted growing attention due to the increasing demands for advanced thermal structure components in ***,hafnium carbide(HfC)whiskers are successfully fabricated in carbon fiber preforms via the polymer-derived ceramic(PDC)method.A novel carbon nanotube(CNT)template growth mechanism combined with the PDC method is proposed in this work,which is different from the conventional vapor–liquid–solid(VLS)mechanism that is commonly used for polymer-derived nanostructured *** CNTs are synthesized and proved to be the templates for fabricating the HfC whiskers,which are generated by the released low-molecular-weight gas such as CO,CO_(2),and CH4 during the pyrolysis of a Hf-containing *** formed products are composed of inner single crystal HfC whiskers that are measured to be several tens of micrometers in length and 100–200 nm in diameter and outer HfC/HfO_(2)*** work not only proposes a new strategy to prepare the HfC whiskers,but also puts forward a new thinking of the efficient utilization of a UHTC polymer precursor.

关键词： HfC whiskers carbon nanotubes(CNTs) CNT template Hf-containing precursor thermal pyrolysis

Cu/Co mixed hierarchical tubular heterostructures for alkaline supercapacitors

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Journal of Materiomics 2021年第3期7卷 640-647页

作者： Ruimei Yuan Hejun Li xuemin yin Peipei Wang Jinhua Lu Leilei Zhang Carbon/Carbon Composites Research Center Northwestern Polytechnical UniversityXi’an710072China

The hierarchical hollow structures of electrode materials s of supercapacitors is effective for the large specific surface area and fast ions and charge *** nanowires as self-engaged templates provide sites and paths for the nucleation and growth of the ***,Cu atoms can disperse into metal organic frameworks(MOFs)to form Cu-Co mixed oxides and construct *** this case,Cu nanowires are used as a template and an activated part to improve the internal electronic *** electrochemical performance can be improved due to these ***,Cu nanowires and MOFs are combined via a mild and efficient approach to fabricate Cu-Co-O/CuO electrode *** electrode exhibits excellent electrochemical performance with a specific capacitance of 834.1 F g^(-1) at 1 A g^(-1).The assembled asymmetric supercapacitor(ASC)shows an ultra-high energy density of 40.7 W h kg^(-1) at a power density of 915 W kg^(-1) and a good capacitance retention after 8000 cycles in a 2 M KOH aqueous *** results otained in this work indicate a strategy of the combination of reactive metals with metal organic frameworks used as electrode materials for electrochemical supercapacitors.

关键词： Oxidizable nanowires MOF-Derived Hierarchical Hollow Energy storage

Hierarchical,seamless,edge-rich nanocarbon hybrid foams for highly efficient electromagnetic-interference shielding

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Journal of Materials Science & Technology 2021年第13期72卷 154-161页

作者： Liyuan Han Qiang Song Kezhi Li xuemin yin Jiajia Sun Hejun Li Fengpei Zhang Xinran Ren Xi Wang State Key Laboratory of Solidification Processing Shannxi Province Key Laboratory of Fiber Reinforced Light Composite MaterialsCarbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an710072China

Lightweight,flexible,ultrahigh-performance electromagnetic-interfe rence(EMI)shielding materials are urgently required in the areas of aircraft/aerospace,portable and wearable ***,1 D carbon nanotubes(CNT)and carbon nanofibers(CNF)with 2 D edge-rich graphene(ERG)are used to form a lightweight,flexible CNT-ERG-CNF hybrid *** foam was fabricated through a self-sacrificial templating chemical vapor deposition process,where nanocarbons bond through covalent bonding,forming a hierarchical 3 D hybridized carbon *** conductive networks and heterogeneous interfaces were constructed using edge-rich nanocarbons to increase the induced currents and interfacial polarization which makes great contributions to achieve high absorption electromagnetic shielding effectiveness(SEA).The CNT-ERG-CNF hybrid foam exhibits EMI shielding effectiveness(SE)exceeding55.4 dB in the X-band while the specific SE(SSE,SE divided by mass density)achieves 9200 dB cm^(3)g^(-1),which surpasses that of nearly all other carbon-based composite ***,the structural stability and durability of the flexible CNT-ERG-CNF hybrid foams is examined by measuring EMI SE after 10000 times cyclic ***,this work not only provides a new idea for preparing hierarchical carbon materials for a wide range of applications,but presents some fundamental insights for achieving higher absorption losses in EMI shielding materials.

关键词： Electromagnetic interference shielding Edge-rich nanocarbons 3D hierarchical hybrid foams Lightweight Flexible

A robust carbon coating of Na_(3)V_(2)(PO_(4))_(3)cathode material for high performance sodium-ion batteries

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Chinese Chemical Letters 2021年第11期32卷 3570-3574页

作者： Liying Shen Yong Li Swagata Roy Xiuping yin Wenbo Liu Shanshan Shi Xuan Wang xuemin yin Jiujun Zhang Yufeng Zhao College of Sciences&Institute for Sustainable Energy Shanghai UniversityShanghai 200444China

Na_(3)V_(2)(PO_(4))_(3)is a very prospective sodium-ion batteries(SIBs)electrode material owing to its NASICON structure and high reversible ***,on account of its intrinsic poor electronic conductivity,Na_(3)V_(2)(PO_(4))_(3)electrode materials confront with some significant limitations like poor cycle and rate performance which inhibit their practical applications in the energy ***,a simple two-step method has been implemented for the successful preparation of carbon-coated Na_(3)V_(2)(PO_(4))_(3)*** synthesized sample shows a remarkable electrochemical performance of 124.1 mAh/g at 0.1 C(1 C=117.6 mA/g),retaining 78.5 mAh/g under a high rate of 200 C and a long cycle-performance(retaining 80.7 mAh/g even after 10000 cycles at 20 C),outperforming the most advanced cathode materials as reported in literatures.

关键词： Sodium-ion batteries NASICON Na_(3)V_(2)(PO_(4))_(3) Cathode Carbon-coated

General formation of Prussian blue analogue microtubes for high-performance Na-ion hybrid supercapacitors

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Science China Materials 2020年第5期63卷 739-747页

作者： xuemin yin Hejun Li Ruimei Yuan Leilei Zhang Jinhua Lu State Key Laboratory of Solidification Processing C/C Composites Research CenterNorthwestern Polytechnical UniversityXi’an 710072China

One-dimensional(1D)hollow-structured nanomaterials with desirable compositions have aroused huge attention in the field of electrochemical energy *** the present study,1D hierarchical cobalt hexacyanoferrate(CoHCF)microtubes were initially fabricated using a facile self-templated method with the electrospun polyacrylonitrile(PAN)-cobalt acetate(Co(Ac)2)as *** the chemical reaction was performed between the templates and a potassium ferricyanide solution,the core-shell PANCo(Ac)2@CoHCF nanofibers were successfully ***,the CoHCF microtubes were finally obtained via the selective dissolution of the PAN-Co(Ac)2 *** from the unique structural characteristic,the CoHCF microtubes electrode exhibited prominent electrochemical characteristics in Na2SO4 aqueous electrolyte,including a high specific capacitance of 281.8 F g^-1(at 1 A g^-1),and good rate capability as well as long cycling stability(93%capacitance retention after 5000 cycles).The hybrid supercapacitor assembled with CoHCF microtubes and activated carbon(AC)as the positive and negative electrodes,respectively,exhibited a high energy density of 43.89 W h kg^-1,a power density of 27.78 k W kg^-1,as well as a long cycle *** that this versatile self-templated synthetic strategy could be extended to fabricate other 1D hollow Prussian blue(PB)or its analogues(PBA)with controllable composition,which have a potential application in a range of fields.

关键词： electrospinning microtubes cobalt hexacyanoferrate,hollow structures hybrid supercapacitors

基于棱边方向检测与运动补偿的视频去隔行算法

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数据采集与处理 2007年第1期22卷 59-66页

作者：殷学民袁建华邹谋炎中国科学院电子学研究所

提出了一种基于棱边方向检测与运动补偿相结合的去隔行算法。首先通过Canny算子提取出棱边,将图像区分为棱边和非棱边两部分。对于棱边丢失的部分,分别在空域内沿棱边方向和时域内沿棱边移动方向插值,然后利用中值滤波得到丢失的棱边信... 详细信息

提出了一种基于棱边方向检测与运动补偿相结合的去隔行算法。首先通过Canny算子提取出棱边,将图像区分为棱边和非棱边两部分。对于棱边丢失的部分,分别在空域内沿棱边方向和时域内沿棱边移动方向插值,然后利用中值滤波得到丢失的棱边信息;对于非棱边部分,采用多级相位相关运动估计法,对当前场与前后两场计算出相应的运动矢量,然后在时域和空域中利用中值滤波计算出丢失的信号。实验结果表明,本文方法优于一般的去隔行算法,如线性空域插值等。同时本文提出了两个去隔行评价标准,可以定量检验去隔行方法的效果。

关键词：视频处理去隔行棱边方向检测运动补偿

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智能化变电站现状及发展趋势分析

现代信息科技 2017年第6期1卷 26-27页

作者：尹学敏湖北三峡职业技术学院湖北宜昌443000

智能化变电站的快速发展已成为电网系统中关键环节之一,从分析智能化变电站的技术特点、存在优势可知,其快速发展的必然性。本文从智能化变电站的发展现状和发展趋势两个方面阐述智能化变电站在电网系统的地位,为电网系统的安全、可靠... 详细信息

智能化变电站的快速发展已成为电网系统中关键环节之一,从分析智能化变电站的技术特点、存在优势可知,其快速发展的必然性。本文从智能化变电站的发展现状和发展趋势两个方面阐述智能化变电站在电网系统的地位,为电网系统的安全、可靠运行提供有力保障。

关键词：智能化变电站发展趋势