检索结果-南通市图书馆

Segmented tomographic evaluation of structural degradation of carbon support in proton exchange membrane fuel cells

Journal of Energy Chemistry 2022年第11期31卷 359-367,I0010页

作者： Jung A.Hong Min-Hyoung Jung Sung Yong Cho Eun-Byeol Park Daehee Yang young-Hoon Kim Sang-Hyeok Yang Woo-Sung Jang Jae Hyuck Jang Hyo June Lee Sungchul Lee hu young jeong young-Min Kim Department of Energy Science Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Fuel Cell Core Parts Development Cell Hyundai Mobis Co.Ltd.Uiwang 16082Republic of Korea Electron Microscopy&Spectroscopy Team Korea Basic Science Institute(KBSI)Daejeon 34133Republic of Korea Graduate School of Semiconductor Materials and Devices Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea

The variation of the three-dimensional(3D)structure of the membrane electrode of a fuel cell during proton exchange cycling involves the corrosion/compaction of the carbon *** increasing degradation of the carbon structure continuously reduces the electrocatalytic performance of proton exchange membrane fuel cells(PEM-FCs).This phenomenon can be explained by performing 3D tomographic analysis at the ***,conventional tomographic approaches which present limited experimental feasibility,cannot perform such evaluation and have not provided sufficient structural information with statistical significance thus ***,a reliable methodology is required for the 3D geometrical evaluation of the carbon ***,we propose a segmented tomographic approach which employs pore network analysis that enables the visualization of the geometrical parameters corresponding to the porous carbon structure at a high *** approach can be utilized to evaluate the 3D structural degradation of the porous carbon structure after cycling in terms of local surface area,pore size distribution,and their 3D *** geometrical parameters of the carbon body were demonstrated to be substantially reduced owing to the cycling-induced *** information enables a deeper understanding of the degradation phenomenon of carbon supports and can contribute to the development of stable PEM-FC electrodes.

关键词： Electron tomography Fuel cell Proton exchange membrane Membrane electrode assembly Carbon corrosion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Multiphase cooperation for multilevel strain accommodation in a single-crystalline BiFeO_(3) thin film

引用

Chinese Physics B 2024年第9期33卷 57-66页

作者： Wooseon Choi Bumsu Park Jaejin Hwang Gyeongtak Han Sang-Hyeok Yang Hyeon Jun Lee Sung Su Lee Ji young Jo Albina Y.Borisevich hu young jeong Sang Ho Oh Jaekwang Lee young-Min Kim Department of Energy Science Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Samsung Electronics Hwaseong 18448Republic of Korea Department of Physics Pusan National UniversityBusan 46241Republic of Korea LG Energy Solution Daejeon 34122Republic of Korea Department of Materials Science and Engineering Kangwon National UniversityRepublic of Korea School of Materials Science and Engineering Gwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea Center for Nanophase Materials Sciences Oak Ridge National LaboratoryTN 37831USA Graduate School of Semiconductor Materials and Devices Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Department of Energy Engineering KENTECH Institute for Energy Materials and DevicesKorea Institute of Energy Technology(KENTECH)Naju 58330Republic of Korea

The functionalities and diverse metastable phases of multiferroic BiFeO_(3)(BFO)thin films depend on the misfit *** mixed phase-induced strain relaxation in multiphase BFO thin films is well known,it is unclear whether a singlecrystalline BFO thin film can accommodate misfit strain without the involvement of its ***,understanding the strain relaxation behavior is key to elucidating the lattice strain–property *** this study,a correlative strain analysis based on dark-field inline electron holography(DIH)and quantitative scanning transmission electron microscopy(STEM)was performed to reveal the structural mechanism for strain accommodation of a single-crystalline BFO thin *** nanoscale DIH strain analysis results indicated a random combination of multiple strain states that acted as a primary strain relief,forming irregularly strained *** STEM-based bond length measurement of the corresponding strained nanodomains revealed a unique strain accommodation behavior achieved by a statistical combination of multiple modes of distorted structures on the unit-cell *** globally integrated strain for each nanodomain was estimated to be close to􀀀1.5%,irrespective of the nanoscale strain states,which was consistent with the fully strained BFO film on the SrTiO_(3) *** functional theory calculations suggested that strain accommodation by the combination of metastable phases was energetically favored compared to single-phase-mediated *** discovery allows a comprehensive understanding of strain accommodation behavior in ferroelectric oxide films,such as BFO,with various low-symmetry polymorphs.

关键词： BiFeO_(3) scanning transmission electronmicroscopy electron holography multiferroic material strain mapping

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The first observation of Ni nanoparticle exsolution from YSZ and its application for dry reforming of methane

引用

Materials Reports(Energy) 2021年第2期1卷 70-76页

作者： Sangwook Joo Chaehyun Lim Ohhun Kwon Linjuan Zhang Jing Zhou Jian-Qiang Wang hu young jeong Yong-wook Sin Sihyuk Choi Guntae Kim Department of Energy Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan698-798Republic of Korea Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai201800PR China UNIST Central Research Facilities and School of Materials Science and Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan44919Republic of Korea Materials&Devices Advanced Research Institute LG ElectronicsSeoulRepublic of Korea Department of Mechanical Engineering Kumoh National Institute of TechnologyGyeongbuk39177Republic of Korea

Ni nanocatalysts produced through exsolution have shown strong resistance to particle sintering and carbon coking in a beneficial dry reforming of methane(DRM)reaction utilizing greenhouse gases such as CH_(4)and CO_(2).However,most of the existing oxide supports for exsolution have been limited to perovskite oxide,while studies on fluorite support have been rarely conducted due to the limited solubility despite its excellent redox *** we demonstrate that 3 mol%Ni can be successfully dissolved into the yttria-stabilized zirconia(YSZ)lattice and be further exsolved to the surface in a reducing *** YSZ decorated with exsolved Ni nanoparticles shows enhanced catalytic activity for DRM reaction compared to the conventional cermet type of bulk ***,the catalytic activity is extremely stable for about 300 h without significant *** results suggest that the YSZ-based fluorite structure can be utilized as one of the support oxides for exsolution.

关键词： Dry forming of methane Exsolution Yttria-stabilized zirconia(YSZ) Ni nanoparticle

来源：

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

Highly ordered lead-free double perovskite halides by design

引用

Journal of Materiomics 2020年第4期6卷 651-660页

作者： Chang Won Ahn Jae hun Jo Jong Chan Kim Hamid Ullah Sangkyun Ryu younghun Hwang Jin San Choi Jongmin Lee Sanghan Lee Hyoungjeen Jeen young-Han Shin hu young jeong Ill Won Kim Tae Heon Kim Department of Physics and Energy Harvest-Storage Research Center(EHSRC) University of UlsanUlsan44610Republic of Korea UNIST Central Research Facilities(UCRF)&School of Materials Science and Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan44919Republic of Korea Multiscale Materials Modelling Laboratory Department of PhysicsUniversity of UlsanUlsan44610Republic of Korea Department of Physics Pusan National UniversityPusan46241Republic of Korea School of Electrical and Electronics Engineering Ulsan CollegeUlsan44610Republic of Korea School of Materials Science and Engineering Gwangju Institute of Science and TechnologyGwangju61005Republic of Korea

Lead-free double perovskite halides are emerging optoelectronic materials that are alternatives to leadbased perovskite ***,single-crystalline double perovskite halides were synthesized,and their intriguing functional properties were *** such pioneering works,lead-free double perovskite halides with better crystallinity are still in demand for applications to novel optoelectronic ***,we realized highly crystalline Cs2AgBiBr6 single crystals with a well-defined atomic ordering on the microscopic *** avoided the formation of Ag vacancies and the subsequent secondary Cs3Bi2Br9 by manipulating the initial chemical environments in hydrothermal *** suppression of Ag vacancies allows us to reduce the trap density in the as-grown crystals and to enhance the carrier mobility *** design strategy is applicable for fabricating other lead-free halide materials with high crystallinity.

关键词： Cs2AgBiBr6 Lead-free Double perovskite Single crystal

来源：

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

High-performance oxygen reduction and evolution carbon catalysis： From mechanistic studies to device integration

引用

Nano Research 2017年第4期10卷 1163-1177页

作者： John W. F. To Jia Wei Desmond Ng Samira Siahrostami Ai Leen Koh Yangjin Lee Zhihua Chen Kara D. Fong Shucheng Chen Jiajun He Won-Gyu Bae Jennifer Wilcox hu young jeong Kwanpyo Kim Felix Studt Jens K. Nфrskov Thomas F. Jaramillo Zhenan Bao Department of Chemical Engineering Stan ford University Stanford CA 94305 USA Institute of Chemical and Engineering Sciences Agency for Science Technology and Research Jurong Island 627833 Singapore Stanford Nano Shared Facilities Stanford University Stanford CA 94305 USA Department of Physics Ulsan National Institute of Science and Technology (UNIST) Ulsan 689-798 Republic of Korea Department of Chemical and Biological Engineering Colorado School of Mines Golden CO 80401 USA UNIST Central Research Facilities (UCRF) Ulsan National Institute of Science and Technology (UNIST) Ulsan 689-798 Republic of Korea SUNCAT Center for Interface Science and Catalysis SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA Institute of Catalysis Research and Technology Karlsruhe Institute of Technology Hermann-von-Helmholtz Platz 1 76344 Eggenstein-Leopoldshafen Germany Institute for Chemical Technology and Polymer Chemistry Karlsruhe Institute of Technology Engesserstr. 18 76131 Karlsruhe Germany

The development of high-performance and low-cost oxygen reduction and evolution catalysts that can be easily integrated into existing devices is crucial for the wide deployment of energy storage systems that utilize O2-H2O chemistries, such as regenerative fuel cells and metal-air batteries. Herein, we report an NHB-activated N-doped hierarchical carbon （NHC） catalyst synthesized via a scalable route, and demonstrate its device integration. The NHC catalyst exhibited good performance for both the oxygen reduction reaction （ORR） and the oxygen evolution reaction （OER）, as demonstrated by means of electrochemical studies and evaluation when integrated into the oxygen electrode of a regenerative fuel cell. The activities observed for both the ORR and the OER were comparable to those achieved by state-of-the-art Pt and Ir catalysts in alkaline environments. We have further identified the critical role of carbon defects as active sites for electrochemical activity through density functional theory calculations and high-resolution TEM visualization. This work highlights the potential of NHC to replace commercial precious metals in regenerative fuel cells and possibly metal-air batteries for cost-effective storage of intermittent renewable energy.

关键词： electrocatalysis porous carbon density functional theory

来源：

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

Microstructure and properties of alumina-silicon carbide nanocomposites fabricated by pressureless sintering and post hot-isostatic pressing

引用

Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 1-6页

作者： young-Keun jeong Koichi NIIHARA National Core Research Center for Hybrid Materials Solution Pusan National University Nagaoka University of Technology

A1203/5%SIC nanocomposites were fabricated by pressureless sintering using MgO as a sintering aid and then post hot-isostatic pressed （HIP）, which can subsequently break through the disadvantage of hot-pressing process. The MgO additive was able to promote the densification of the composites, but could not induce the grain growth of A1203 matrix due to the grain growth inhibition by nano-sized SiC particles. After HIP treatment, A12OJSiC nanocomposites achieved full densification and homogeneous distribution of nano-sized SiC particles. Moreover, the fracture morphology of HIP treated specimens was identical with that of the hot-pressed A1203/SiC nanocomposites showing complete transgranular fracture. Consequently, high fracture strength of 1 GPa was achieved for the A1203/5%SIC nanocomposites by pressureless sintering and post HIP process.

关键词： nanocomposite pressureless sintering fracture strength

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of foundation damage and water-level change on vibration modal parameters of gravity-type caisson structure

引用

Science China(Technological Sciences) 2015年第2期58卷 316-329页

作者： LEE So-young KIM jeong-Tae Department of Ocean Engineering Pukyong National University

In this paper,the effects of foundation damage and water-level change on vibration characteristics of gravity-type caisson structure are examined by analyzing modal parameters extracted from output-only *** achieve the objective,the following approaches are ***,vibration response analysis methods are selected to estimate power spectral density and modal parameters such as natural frequency,damping ratio and mode shape of a lab-scale caisson structural ***,vibration tests on the lab-scale caisson system are performed under a series of test scenarios which include three water-level changes and three damage ***,experimental modal parameters corresponding to the damaging cases as well as the water level cases are extracted by frequency domain decomposition method and stochastic subspace identification ***,the effects of the water-level variation and foundation damage on the extracted modal parameters are examined to assess the feasibility of the vibration-based damage detection in gravity-type caisson structures under water-level uncertainty.

关键词： caisson structure gravity-type structure modal parameter effect of water-level foundation damage

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Feasibility Study of R134a/R404a Cascade Heat Pump Cycle in Heat Pump Dryers with Electrical Heaters at Low Temperatures

引用

Journal of Thermal Science 2015年第5期24卷 463-467页

作者： Ji Woo jeong young Lim Lee Dept. of Mechanical Engineering Kongju National University Dept. of Mechanical and Automotive Engineering Kongju National University

Heat pump cycles have been widely applied to dryers for their high efficiency. However, low–efficiency electrical heaters are often used during early drying stage for frozen foods or winter since a standard heat pump cycle cannot operate at low temperature. This study introduced cascade heat pumps replacing electrical heaters to improve dryer performance at low temperatures. Experiments were performed to examine changes in performance of the cascade heat pump dryers in relation to ambient temperature, low-stage cycle mass flow rate, and high-stage cycle mass flow rate. The results showed a significant improvement in low-temperature dryer performance with the introduction of cascade heat pump cycles.

关键词： Cascade cycle R134a/R404a Heat pump dryer COP Energy efficiency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of pulse time on surface characteristics and corrosion resistance during pulse electrochemical polishing

引用

中国有色金属学会会刊：英文版 2012年第S3期22卷 876-880页

作者： young-Bin KIM jeong-Woo PARK Department of Advanced Parts and Materials Engineering Chosun University Department of Mechanical Design Engineering Chosun University

Pulse electrochemical polishing (PECP) was used to improve the mechanical properties,such as surface roughness and corrosion resistance,of conductive metallic *** can provide a smooth,bright,reflective,and deburred surface that exhibits superior corrosion *** this work,stainless steel was used as the anode,and copper was used as the cathode due to their low electrical *** surface roughness of the PECP sample was measured by atomic force microscopy (AFM).A scanning electron microscope (SEM) was used to observe surface characteristics,and an Auger electron spectroscope (AES) was used to analyze the metallurgical composition and thickness of the passive *** aim of this research was to compare the corrosion resistance rates of the unprocessed and PECP-processed stainless steel.

关键词： stainless stell pulse electrochemical polishing corrosion resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hydrogen sulfide controls peripheral nerve degeneration and regeneration:a novel therapeutic strategy for peripheral demyelinating disorders or nerve degenerative diseases

引用

Neural Regeneration Research 2014年第24期9卷 2119-2121页

作者： Junyang Jung Na young jeong Department of Anatomy and Neurobiology School of Medicine Biomedical Science Institution Kyung Hee University Department of Anatomy and Cell Biology College of Medicine Dong-A University

After peripheral nerve injury, the process of Wallerian degeneration is initiated in the distal stump of injured nerves. Wallerian degeneration in peripheral nerves involves axonal degeneration and degradation of the myelin sheath in Schwann cells. This provides the necessary conditions for axonal regeneration and remyelination. After nerve injury, macrophages are also recruited to the distal nerve stump and, together with Schwann cells, play a role in the clearance of myelin debris.

关键词： Hydrogen sulfide controls peripheral nerve degeneration and regeneration Figure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：