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Realizing enhanced energy storage and hardness performances in 0.90NaNbO_(3)-0.10Bi(Zn_(0.5)Sn_(0.5))O_(3)ceramics

Journal of Advanced Ceramics 2022年第5期11卷 729-741页

作者： Xiaoyan DONG Xu LI hongyun chen Qinpeng DONG Jiaming WANG Xiang WANG Yue PAN Xiuli chen Huanfu ZHOU Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi Key Laboratory of Nonferrous Materials and New Processing TechnologyMinistry of EducationSchool of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China College of Materials Science and Engineering Sichuan UniversityChengdu 610064China

Ceramic dielectric capacitors have a broad scope of application in pulsed power supply *** behavior has manifested decent energy storage capabilities in dielectric materials due to its fast polarization *** addition,an ultrahigh energy storage density can also be achieved in NaNbO_(3)(NN)-based ceramics by combining antiferroelectric and relaxor *** of the existing reports about lead-free dielectric ceramics,nevertheless,still lack the relevant research about domain evolution and relaxor ***,a novel lead-free solid solution,(1-x)NaNbO_(3)-xBi(Zn_(0.5)Sn_(0.5))O_(3)(abbreviated as xBZS,x=0.05,0.10,0.15,and 0.20)was designed to analyze the domain evolution and relaxor *** evolutions in xBZS ceramics confirmed the contribution of the relaxor behavior to their decent energy storage characteristics caused by the fast polarization rotation according to the low energy barrier of polar nanoregions(PNRs).Consequently,a high energy storage density of 3.14 J/cm^(3)and energy efficiency of 83.30%are simultaneously available with 0.10 BZS ceramics,together with stable energy storage properties over a large temperature range(20-100℃)and a wide frequency range(1-200 Hz).Additionally,for practical applications,the 0.10 BZS ceramics display a high discharge energy storage density(W_(dis)≈1.05 J/cm^(3)),fast discharge rate(t_(0.9)≈60.60 ns),and high hardness(H≈5.49 GPa).This study offers significant insights on the mechanisms of high performance lead-free ceramic energy storage materials.

关键词： energy storage NaNbO3(NN)-based domain evolutions hardness

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Enhanced thermal and frequency stability and decent fatigue endurance in lead-free NaNbO_(3) -based ceramics with high energy storage density and efficiency

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Journal of Materiomics 2022年第2期8卷 489-497页

作者： hongyun chen Junpeng Shi Xiaoyan Dong Feihong Pang Hailin Zhang Xiuli chen Huanfu Zhou School of Materials Science and Engineering Guilin University of TechnologyGuilin 541004China

Lead-free ceramic capacitors have the application prospect in the dielectric pulse power system due to the advantages of large dielectric constant,lower dielectric loss and good temperature ***-theless,most reported dielectric ceramics have limitation of realizing large energy storage density(W_(rec))and high energy storage efficiency(h)simultaneously due to the low breakdown electric field(E_(b)),low maximum polarization and large remanent polarization(P_(r)).These issues above can be settled by raising the bulk resistivity of dielectric ceramics and optimizing domain ***,we designed a new system by doping(Bi_(0.5)Na_(0.5))_(0.7)Sr_(0.3)TiO_(3) into 0.9NaNbO_(3)-0.1Bi(Ni_(0.5)Zr_(0.5))O_(3) ceramics,which simulta-neously obtained a higher bulk resistivity by decreasing the grain size and achieved a smaller P_(r) by optimizing domain structure,thus the better E_(b) of 530 kV/cm and W_(rec) of 6.43 J/cm^(3) were achieved,h was improved from 34%to 82%.Besides,the 0.4BNST ceramics show excellent temperature,frequency and fatigue stability under the conditions of 20-180℃,1-100 Hz and 104 cycles,***-while,superior power density(P_(D)=107 MW/cm^(3)),large current density(C_(D)=1070 A/cm^(2))and discharge speed(1.025 m s)were achieved in 0.4BNST ***,the charge-discharge performance displayed good temperature stability in the temperature range of 30℃-180℃.The above results indicated that the ceramics have potential practical value in the field of energy storage capacitor.

关键词： Breakdown electric field Excellent dielectric stability Charge-discharge performance Potential value

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High energy storage density and power density achieved simultaneously in NaNbO_(3)-based lead-free ceramics via antiferroelectricity enhancement

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Journal of Materiomics 2021年第3期7卷 629-639页

作者： Xiaoyan Dong Xu Li Xiuli chen hongyun chen Congcong Sun Junpeng Shi Feihong Pang Huanfu Zhou Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi Key Laboratory of Nonferrous Materials and New Processing TechnologyMinistry of EducationSchool of Materials Science and EngineeringGuilin University of TechnologyGuilin541004China

High-performance lead-free dielectric ceramics with simultaneously high energy storage density and power density are in high demanded for pulse power *** realize excellent energy-storage characteristics,a strategy to enhance antiferroelectricity and construct a local random field simultaneously was proposed in this *** on the above strategy,a series of(1-x)NaNbO_(3)-xBi(Ni_(1/2)Sn_(1/2))O3[xBNS,x=0.05,0.10,0.15,0.20,and 0.22]solid solutions were designed and *** ultrahigh energy storage density(Utotal)of 7.35 J/cm^(3),and recoverable energy density(Urec)of 5.00 J/cm^(3) were achieved in the 0.10BNS *** addition,an adequate stability of energy storage properties at a range of temperatures(20e140℃),frequencies(1e100 Hz),and fatigue test durations(1e1-10^(4) cycles)were realized in 0.10BNS ceramics.0.10BNS ceramics displayed a high current density of 1005 A/cm2,an ultrahigh power density of 100.5 MW/cm^(3,)and an ultrashort discharge time of 46.5 ns?This remarkable performance not only justified our strategy but also confirmed 0.10BNS ceramics as a promising candidate for energy storage.

关键词： Lead-free ceramics Energy storage NaNbO_(3)-Based Power density

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Understanding the Contributing Factors to Nighttime Crashes at Freeway Mainline Segments

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Journal of Transportation Technologies 2019年第4期9卷 450-461页

作者： hongyun chen Kristiansson Fanny Department of Civil Engineering Embry-Riddle Aeronautical University Daytona Beach FL USA

This study investigated the crash contributing factors to the injury outcomes and the characteristics of the night time crashes at freeway mainline segments. Multinomial logit model (MNL) was selected to estimate the explanatory variables at a 95% confidence level. The six-year crash data (2005-2010) were obtained in the State of Florida, USA and five injury level outcomes, no injury, possible injury, non-incapacitating injury, capacitating injury, and fatal injury, were considered. The no injury level was selected as the baseline category.

关键词： Contributing Factors Nighttime Crash Injury Severity Freeway Mainline

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Paleoenvironmental Record from Wuqi Paleolake in Northern Chinese Loess Plateau

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Acta Geologica Sinica(English Edition) 2014年第S1期88卷 8-9页

作者： GUO Jiao WANG Wei WU Lijie chen hongyun DONG Qiuyao Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological Sciences

Jinding core(ZK04,36°47′35.36″N,108°19′05.24″E)is located in the northern area of Luohe river basin,northern Chinese loess plateau,lying to the southeast of Wuqi County about 20 *** total depth of Core ZK04 is 9... 详细信息

关键词： Wuqi paleolake magnetic susceptibility grain size paleomagnetic chronology paleoenvironment Chinese Loess Plateau

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Investigation Motorcycle Safety at Exit Ramp Sections by Analyzing Historical Crash Data and Rider’s Perception

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Journal of Transportation Technologies 2014年第1期4卷 107-115页

作者： hongyun chen Chanyoung Lee Pei-Sung Lin Center for Urban Transportation Research University of South Florida Tampa USA Department of Civil Engineering Embry-Riddle Aeronautical University Daytona Beach USA

The purpose of this study is to evaluate the safety performance of four exit ramp types and the major contributing factors on motorcycle crashes and injury severity of motorcycle riders. A six-year crash data were collected in Florida, and a web-based survey (234 samples) was conducted. 573 crashes were found at 419 exits, including 178 diamond exits, 71 directional exits, 85 loop exits and 85 outer connection exits. For a diamond exit, both the survey and crash data showed that this type was safer and more preferable by motorcycle riders;while a loop exit was the most dangerous exit due to the sharp curve and a certain length of curve with limited visibility. For a directional exit, longer ramp lengths and the reverse curvature are the major factors causing motorcycle crashes. For an outer connection exit, the riders rated it as a safe type;however, the data showed higher average crash frequency and rate than those at diamond exits or directional exits. The possible reason could be the unexpected curvature in the middle of the ramp, which could be dangerous if the rider is not familiar with the exit ramp location or doesn’t pay attention to the ramp curvatures. The crash predictive model was developed, and the result indicated that if all remained the same, a directional exit, a loop exit, or an outer connection exit will have 16%, 27%, and 42% more crashes than a diamond exit, respectively. The findings from this study can help policy-makers and engineers to develop and apply effective countermeasures to reduce motorcycle crashes and injury severity levels for different exit ramp types.

关键词： Motorcycle Safety Exit Ramp Configurations Crash Modeling Riders’ Survey

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Impact of COVID-19 on Safety Performance for Motorcycles: Pre-and during-Pandemic Conditions

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Journal of Transportation Technologies 2024年第3期14卷 390-401页

作者： hongyun chen Amelia Lawson Charles Hurda Madalyn Smith Tate Grant Civil Engineering Department Embry-Riddle Aeronautical University Daytona Beach FL USA

Florida has the highest number of motorcycle fatalities in the United States and contains the second largest population of registered motorcycles. The COVID-19 pandemic influenced the roads, traffic, and driving behavior in the continental United States. Motorcycle crashes decreased during the COVID-19 years (2020 and 2021) while the fatality rates increased. The purpose of this study is to 1) investigate motorcycle crashes before and during the Pandemic period to understand the impacts on motorcycle safety and contributing factors to the crash severity levels;2) develop the crash predictive model for different degrees of severity in motorcycle crashes in Florida. Florida statewide crash data were collected. T tests have been conducted to compare the contributing factors between two periods. The injury severities are significantly different among all five levels between those during normal period and the Pandemic period. A crash predictive model has been developed to determine the facts to injury severity levels for motorcycle crashes. A total of eight variables are found to significantly increase the injury severity levels for motorcycle crashes during the Pandemic period.

关键词： Motorcycle Crash Pandemic Injury Severity Contributing Factors

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缅甸国家档案馆馆藏当代中缅关系档案资料评介

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中共党史研究 2019年第6期 117-122页

作者：陈洪运厦门大学南洋研究院 /国际关系学院

近年来,中国与周边国家及地区的外交史研究成为一股新的学术潮流。国内诸多高校和科研机构纷纷成立周边外交研究机构,加强人才培养和学科建设,但显然"中国周边外交研究尚处于滞后且未成型状态"①,主要原因在于相关研究缺少对象国的档案... 详细信息

近年来,中国与周边国家及地区的外交史研究成为一股新的学术潮流。国内诸多高校和科研机构纷纷成立周边外交研究机构,加强人才培养和学科建设,但显然"中国周边外交研究尚处于滞后且未成型状态"①,主要原因在于相关研究缺少对象国的档案史料。

关键词：国家档案馆档案资料中缅关系评介当代馆藏缅甸周边外交

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Risk factors for progressive ischemic stroke: A retrospective analysis

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Neural Regeneration Research 2007年第11期2卷 698-701页

作者： Ding Qin Junhong chen hongyun Jiao Jing Yi Ying Zhang Fengsheng Li Department of Neurology General Hospital of Beijing Coal Mining Group Beijing 102300 China

BACKGROUND： Progressive ischemic stroke has higher fatality rate and disability rate than common cerebral infarction, thus it is very significant to investigate the early predicting factors related to the occurrence of progressive ischemic stroke, the potential pathological mechanism and the risk factors of early intervention for preventing the occurrence of progressive ischemic stroke and ameliorating its outcome. OBJECTIVE： To analyze the possible related risk factors in patients with progressive ishcemic stroke, so as to provide reference for the prevention and treatment of progressive ishcemic stroke. DESIGN： A retrospective analysis. SETTING： Department of Neurology, General Hospital of Beijing Coal Mining Group. PARTICIPANTS： Totally 280 patients with progressive ischemic stroke were selected from the Department of Neurology, General Hospital of Beijing Coal Mining Group from March 2002 to June 2006, including 192 males and 88 females, with a mean age of （62±7） years old. They were all accorded with the diagnostic standards for cerebral infarction set by the Fourth National Academic Meeting for Cerebrovascular Disease in 1995, and confired by CT or MRI, admitted within 24 hours after attack, and the neurological defect progressed gradually or aggravated in gradients within 72 hours after attack, and the aggravation of neurological defect was defined as the neurological deficit score decreased by more than 2 points. Meanwhile, 200 inpatients with non-progressive ischemic stroke （135 males and 65 females） were selected as the control group. METHODS： After admission, a univariate analysis of variance was conducted using the factors of blood pressure, history of diabetes mellitus, fever, leukocytosis, levels of blood lipids, fibrinogen, blood glucose and plasma homocysteine, cerebral arterial stenosis, and CT symptoms of early infarction, and the significant factors were involved in the multivariate non-conditional Logistic regression analysis. MAIN OU

关键词： progress ischemic stroke risk factors retrospective analysis

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国外乡村公路交通事故主要致因综述

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公路交通科技 2009年第11期26卷 123-131,135页

作者：高建刚陈宏云郑昊陈强交通部公路科学研究院公路交通安全技术交通行业重点实验室北京100088 北京交通大学交通运输学院北京100044

根据美国、加拿大、英国、澳大利亚等国关于乡村公路交通事故的数据和资料,以人的行为为重点,对乡村公路交通事故的致因进行归纳分析,主要有:第一,乡村公路上男性、年轻人、轻型货车乘员和后座乘员的安全带使用率较低;第二,乡村公路上... 详细信息

根据美国、加拿大、英国、澳大利亚等国关于乡村公路交通事故的数据和资料,以人的行为为重点,对乡村公路交通事故的致因进行归纳分析,主要有:第一,乡村公路上男性、年轻人、轻型货车乘员和后座乘员的安全带使用率较低;第二,乡村公路上男性和年轻人倾向于超速行驶,摩托车和小型车超速行驶的比例较高,在周末和夜间超速行驶的比例较高;第三,男性和年轻人是乡村公路上酒后驾驶的主要人群,周末和夜晚因酒后驾驶导致的交通事故较多;第四,乡村公路交通事故中男性疲劳驾驶的比例低于女性,年轻人疲劳驾驶的比例仍较高,周末、夜间和下午的因疲劳驾驶导致的交通事故较多;第五,65岁以上的老年驾驶员容易在乡村公路上发生由于未按规定让行和不遵守交通信号指挥而造成的交通事故;第六,导致乡村公路交通事故的道路环境因素主要有道路环境突变、车道狭窄、弯道半径过小、安全视距不够等;第七,乡村公路的交通事故救援响应慢、质量低、效果差。

关键词：交通工程交通事故致因文献综述乡村公路交通事故

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