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defects mediated ferromagnetism in a V-doped 6H-SiC single crystal

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Chinese Physics B 2012年第6期21卷 494-497页

作者：卓世异刘学超熊泽闫文盛忻隽杨建华施尔畏 Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai 200050China Graduate University of the Chinese Academy of Sciences Beijing 100049China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

Undoped and V-doped 6H-SiC single crystals have been grown by the physical vapor transport method.The V concentration is determined to be 3.76×10^17 at/cm^3 and 6.14×10^17 at/cm^3 by secondary ion mass spectrometry for low V-doped and high V-doped SiC samples,respectively.The undoped 6H-SiC shows diamagnetism,while the V-doped 6H-SiC exhibits weak ferromagnetism.The lower V-doped sample shows stronger ferromagnetism compared to that of the higher V-doped sample.However,the structural characterization indicates that the lower V-doped SiC has a relative poor crystalline quality.It is found that both V dopants and defects are essential for introducing ferromagnetic exchange in V-doped SiC single crystals.

关键词： V-doping 6H-SiC defects magnetic materials

defects in perovskite crystals

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Journal of Semiconductors 2023年第8期44卷 1-6页

作者： Zhimin Fang Jie Sun Shengzhong(Frank)Liu Liming Ding Key Laboratory of Applied Surface and Colloid Chemistry(MoE) School of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710119China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Perovskite solar cell(PSC) is now a shining star in photovoltaics field[1].Benefiting from excellent optoelectronic properties of perovskite materials,the certified power conversion efficiency(PCE)of PSCs has reached 26.0%[2],showing great potential for commercialization.In essence,the efficiency of solar cells is determined by the radiative and nonradiative recombination of photogenerated charge carriers.The unfavorable nonradiative recombination mainly assisted by the trap states leads to severe charge carrier loss and thus unsatisfactory efficiency.

关键词： perovskite charge defects

Transcatheter Closure of Atrial Septal defects Improves Cardiac Remodeling and Function of Adult Patients with Permanent Atrial Fibrillation

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Chinese Medical Journal 2015年第6期128卷 780-783页

作者： Liang Chen Yuan Bai Fei-Yu Wang Zhi-Gang Zhang Xing-Hua Shan Tao Chen Xian-Xian Zhao Yong-Wen Qin Department of Cardiology Changhai Hospital Second Military Medical University Shanghai 200433 China Department of Cardiology Fuzhou General Rospital of Nanjing Military Command I:uzhou-Fujian 350025 China Standardized Base for Trainin'gResidents Changhai 'Hospital Second Mil~ary Medical University Shanghai 200433 China

Background:Permanent atrial fibrillation (AF) is the most common form of dysrhythmia associated with atrial septal defects (ASDs) in patients older than 40 years.However,little is known about cardiac remodeling after transcatheter closure in patients with permanent AF.This study was designed to compare cardiac events and remodeling effects after transcatheter closure in such patients.Methods:Clinical data of 289 adult patients older than 40 years who underwent ASD closure at our center were analyzed retrospectively.Of them,63 patients with permanent AF were assigned to the case group,and the other 226 patients without permanent AF were assigned to the control group.Cardiac events and changes in left and right cardiac cavity dimensions before the procedure and 6 months after the procedure were compared between the two groups.Results:Patients in the case group were significantly older than those in the control group.The right ventricular (RV) volume and right atrial (RA) volume were decreased significantly in both the groups during a median follow-up period of 6 months after closure (P ＜ 0.001).The left atrial dimensions,left ventricular end-systolic dimensions,left ventricular end-diastolic dimensions and left ventricular ejection fraction showed no significant change before and after the procedure in both the groups.Changes of the RV volume and RA volume in the case group were significantly smaller than those in the control group (P =0.005 and P ＜ 0.001).The New York Heart Association cardiac function was improved in both the groups during the 6 months follow-up period.Conclusions:The transcatheter closure of ASD can improve the cardiac remodeling and cardiac function in patients with or without AF.

关键词： Atrial Fibrillation Cardiac Catheterization Heart Septal defects Atrial

Organic Passivation of Deep defects in Cu(In,Ga)Se_(2) Film for Geometry-Simplified Compound Solar Cells

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Research 2023年第4期2023卷 425-435页

作者： Jingwei Chen Xuan Chang Jianxin Guo Qing Gao Xuning Zhang Chenxu Liu Xueliang Yang Xin Zhou Bingbing Chen Feng Li Jianming Wang Xiaobing Yan Dengyuan Song Han Li Benjamin S.Flavel Shufang Wang Jianhui Chen Advanced Passivation Technology Lab College of Physics Science and TechnologyHebei UniversityBaoding071002China State Key Laboratory of Photovoltaic Materials&Technology Yingli Green Energy Holding Co.Ltd.Baoding 071051China Das Solar Co. Ltd.No 43 Bailing South RoadQuzhou Green Industry Clustering ZoneQuzhouZhejiang Province324022China Institute of Nanotechnology Karlsruhe Institute of TechnologyHermann-von-Helmholtz-Platz 1EggensteinLeopoldshafen76344Germany.

Diverse defects in copper indium gallium diselenide solar cells cause nonradiative recombination losses and impair device performance.Here,an organic passivation scheme for surface and grain boundary defects is reported,which employs an organic passivation agent to infiltrate the copper indium gallium diselenide thin films.A transparent conductive passivating(TCP)film is then developed by incorporating metal nanowires into the organic polymer and used in solar cells.The TCP films have a transmittance of more than 90%in the visible and nearinfrared spectra and a sheet resistance of~10.5Ω/sq.This leads to improvements in the open-circuit voltage and the efficiency of the organic passivated solar cells compared with control cells and paves the way for novel approaches to copper indium gallium diselenide defect passivation and possibly other compound solar cells.

关键词： copper visible defects

The performance of transrectal ultrasound in the diagnosis of seminal vesicle defects： a comparison with magnetic resonance imaging

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Asian Journal of Andrology 2014年第6期16卷 907-911页

作者： Xu Chen Hua Wang Rong-Pei Wu Hui Liang Xiao-Peng Mao Cheng-Qiang Mao Hong-Zhang Zhu Shao-Peng Qiu Dao-Hu Wang Department of Urology The First Affiliated Hospital Sun Yat-Sen University Guangzhou 510080 China Department of Urology People's Hospital of New District Longhua Shenzhen 518109 China Department of Radiology The First Affiliated Hospital Sun Yat-Sen University Guangzhou 510080 China.

Obstructive azoospermia （OA） is one of the most common causes of male infertility. Transrectal ultrasound （TRUS） has been used to diagnose OA for many years. From 2009 to 2013, we evaluated a prospective cohort of 1249 patients with suspected OA using TRUS. It was found that dilation of the ejaculatory duct （ED）（29.9%, 374/1249） was the most common cause of OA, followed by seminal vesicle （SV） abnormalities （28.5%, 356/1249）. A total of 237 patients were diagnosed with congenital defects （agenesis and/or hypoplasia） of the SV, constituting more than half of the cases of SV disease in OA （19.0%, 237/1249）. In contrast to ED, congenital defects of the SV could not be corrected with surgical treatment. Therefore, it is meaningful to compare TRUS and magnetic resonance imaging （MRI） for accurate diagnosis of SV defects. Among our patients, 30 with agenesis or/and hypoplasia of the SV on TRUS were further evaluated using pelvic MRI within 2 years, with the objective of verifying the TRUS results. The concordance rate for diagnosing congenital defects of the SV was 73.3% （22/30）. We concluded that TRUS is a reliable and convenient method for diagnosing agenesis or hypoplasia of the SV in OA patients with a high concordance with MRI while MRI is useful in patients with inconclusive TRUS findings.

关键词： defects magnetic resonance imaging obstructive azoospermia seminal vesicle transrectal ultrasound

defects in Concrete Elements: A Study of Residential Buildings of 30 Years and above in Onitsha Metropolis, Anambra State, Nigeria

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Journal of Building Construction and Planning Research 2022年第3期10卷 102-123页

作者： Chiamaka Ogochukwu Obiora Fidelis Okechukwu Ezeokoli Chritopher Chidi Belonwu Francisca Nkachukwu Okeke Department of Building Nnamdi Azikiwe University Awka Anambra State Nigeria Department of Building Niger Delta University Wilberforce Island Amasoma Bayelsa State Nigeria Department of Quantity Surveying Enugu State University of Science and Technology Agbani Enugu State Nigeria

Building defect is an issue in existing buildings that needs urgent tackling to prevent further problems. This study assessed the defects in concrete elements in residential buildings of 30 years and above in the Onitsha metropolis of Anambra State, Nigeria. Data collection instruments in the study include structured questionnaire, interviews, visual inspection/observations, archival records, recordings, photographs;and non-destructive testing of the concrete elements in an existing building in the study area. The population of this study constituted of the construction registered professionals and the existing buildings in study area. The sample for the study was based on the calculated sample size using Taro Yamani Formula. A total of 158 registered professionals were sampled from the population of 260. The questionnaires were purposively distributed to the registered professionals up to the required sample sizes of 158 and 129 questionnaires were properly filled and returned. The study used the SPSS and Microsoft Excel to analyze the data. The results were analyzed in percentages and figures using descriptive statistics and presented in the form of pie charts and tables. The finding of the study revealed that the causes and effects of structural defects on the concrete elements in existing buildings in the study area according to the rating are;exposed/corrosion of the embedded metals, faulty workmanship, overload and impacts, chemical attack, freeze-thaw deterioration, fire/heat, restraint to volume change. The visual observation revealed that the structural elements are characterized by heavy defects such as deep vertical, horizontal and diagonal cracks, exposed/ corrosion of the embedded metals, spalling of the concrete slabs. The existence of defects in the concrete members led to the low compressive strength of the concrete elements and the structural instability of the existing buildings as revealed by the non-destructive test. The non-destructive test result revealed that most of the tested concrete ele

关键词： Construction Industry Building Professionals Concrete Elements defects Residential Buildings Structural Stability Non-Destructive Test Compressive Strength

defects of Polymer-derived Si-C-O Fibers and Their Originations

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Journal of Wuhan University of Technology(Materials Science) 2004年第1期19卷 36-40页

作者：楚增勇 National University of Defense Technology

defects of polymer-derived Si-C-O fibers were intensively studied by the SEM and TEM techniques and their originations were also discussed on the basis of factors experiments.The defects were found mainly in the form of strumaes,pits and splits on surfaces as well as microflaw networks,porosity clusters and inclusions in the bulk.Factors experiments reveal that a nonuniform or an insufficient curing would result in larger-sized strumaes or interior microflaws.Gas evolution rates due to different firing rates have a great influence on the formation of internal microflaws or porosity clusters and some oxidation-induced pits or splits may be formed on surfaces because of a trace of oxygen or water vapor accumulated from the flowing inert atmosphere during pyrolysis.

关键词： defects Si-C-O fiber polymer-derived ceramic

Demographic Characteristics and Environmental Risk Factors Exposure of Birth defects in Pregnant Women: A Population-based Study

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Biomedical and Environmental Sciences 2019年第1期32卷 51-57页

作者： LIN Hong LUO Mi Yang LUO Jia You ZENG Rong LI Ya Mei DU Qi Yun FANG Jun Qun Xiangya School of Public Health Central South University Saw Swee Hock School of Public Health National University of Singapore Xiangya Hospital of Central South University Hunan Provincial Maternal and Child Health Care Hospital

Worldwide, the incidence of birth defects in low-income countries is 6.42%, while in middle-income and high-income countries it is 5.57% and 4.72%, respectively;approximately 303, 000 newborns die from birth defects each year. In China, the incidence of birth defects is about 5.6%, and around 8.14 million people have congenital disabilities, accounting for 9.6% of total disabled people[1]. Birth defect remains a major clinical and public health challenge because of its high fatality rate and protracted and severe sequela.

关键词： Birth defects demographics Environmental risk factors

Electron paramagnetic resonance characterization of aluminum ion implantation-induced defects in 4H-SiC

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Nanotechnology and Precision Engineering 2019年第4期2卷 157-162页

作者： Xiuhong Wang Zongwei Xua Mathias Rommel Bing Dong Le Song Clarence Augustine TH Tee Fengzhou Fang State Key Laboratory of Precision Measuring Technology&Instruments Tianjin UniversityTianjin 300072China Fraunhofer Institute for Integrated Systems and Device Technology(IISB) Schottkystrasse 10Erlangen 91058Germany Department of Electrical Engineering Faculty of EngineeringUniversity of MalayaKuala Lumpur 50603Malaysia Centre of Advanced Research Enabler Facility Faculty of EngineeringUniversity of MalayaKuala Lumpur 50603Malaysia

Deep-level defects in silicon carbide(SiC)are critical to the control of the performance of SiC electron devices.In this paper,deep-level defects in aluminumion-implanted 4H-SiC after high-temperature annealingwere studied using electron paramagnetic resonance(EPR)spectroscopy at temperatures of 77 K and 123 K under different illumination conditions.Results showed that the main defect in aluminum ion-implanted 4H-SiC was the positively charged carbon vacancy(VC+),and the higher the doping concentration was,the higher was the concentration of VC+.Itwas found that the type of material defectwas independent of the doping concentration,although more VC+defects were detected during photoexcitation and at lower temperatures.These results should be helpful in the fundamental research of p-type 4H-SiC fabrication in accordance with functional device development.

关键词： Electron paramagnetic resonance Silicon carbide defects Carbon vacancy