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Defects evolution in n-type 4H-Sic induced by electron irradiation and annealing

Journal of Semiconductors 2024年第7期45卷 77-83页

作者： Huifan Xiong Xuesong Lu Xu Gao Yuchao Yan Shuai Liu Lihui Song Deren Yang Xiaodong pi State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Key Laboratory of Power Semiconductor Materials and Devices of Zhejiang Province&Institute of Advanced Semiconductors ZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 311200China

Radiation damage produced in 4H-Sic by electrons of different doses is presented by using multiple characterization techniques. Raman spectra results indicate that Sic crystal structures are essentially impervious to 10 Me v electron irradiation with doses up to 3000 kGy. However, irradiation indeed leads to the generation of various defects, which are evaluated through photoluminescence(PL) and deep level transient spectroscopy(DLTS). The PL spectra feature a prominent broad band centered at 500 nm, accompanied by several smaller peaks ranging from 660 to 808 nm. The intensity of each PL peak demonstrates a linear correlation with the irradiation dose, indicating a proportional increase in defect concentration during irradiation. The DLTS spectra reveal several thermally unstable and stable defects that exhibit similarities at low irradiation ***, after irradiating at the higher dose of 1000 kGy, a new stable defect labeled as R_(2)(Ec-0.51 ev) appeared after annealing at 800 K. Furthermore, the impact of irradiation-induced defects on Sic junction barrier Schottky diodes is discussed. It is observed that high-dose electron irradiation converts Sic n-epilayers to semi-insulating layers. However, subjecting the samples to a temperature of only 800 K results in a significant reduction in resistance due to the annealing out of unstable defects.

关键词： 4H-Sic deep level transient spectroscopy(DLTS) photoluminescence(PL) defects

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Suppression of cs FAD3 in a JA-dependent manner, but not through the SA pathway, impairs drought stress tolerance in tea

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Journal of Integrative Agriculture 2024年第11期23卷 3737-3750页

作者： Na chang Xiaotian pi Ziwen Zhou Yeyun Li Xianchen Zhang State Key Laboratory of Tea Plant Biology and Utilization Anhui Agricultural University

The growth and yield of tea plants are seriously limited by drought stress. Fatty acid desaturases（FADs） contribute to the mediation of membrane fluidity in response to different stresses, although the role of ω-3 FAD（Omega-3fatty acid desaturase）-mediated damage induced by drought stress in tea plants is poorly understood. In this study,drought stress significantly promoted the synthesis of c18:3（linolenic acid） and the expression level of *** experiments further demonstrated that csFAD3 can convert c18:2 to c18:3, and that the 35S:GFP-csFAD3fusion protein was localized in the endoplasmic reticulum of Nicotiana benthamiana cells. csFAD3-silenced tea leaves exhibited poor drought tolerance, with a lower Fv/Fmand a higher malondialdehyde（MDA） content than the control plants. However, transgenic 35S:csFAD3 Arabidopsis plants showed the opposite phenotypes. In addition,the jasmonic acid（JA） content and the expression levels of csLOX2, csLOX4, csAOS, csAOc3 and csOPR2 were significantly reduced in csFAD3-silenced leaves under drought stress. However, no substantial difference in the salicylic acid（SA） content was detected under normal or drought conditions. An analysis of Atcoi1（JA receptor） or Atnpr1（SA receptor） mutant Arabidopsis plants in 35S:csFAD3 backgrounds further revealed that knockout of Atcoi1impaired the drought-tolerant phenotypes of csFAD3 overexpression lines. Therefore, this study demonstrated that csFAD3 plays a crucial role in drought tolerance by mediating JA pathways.

关键词： tea plants csFAD3 drought stress jasmonic acid

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南非干燥台地灌木放牧研究

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国外畜牧学（草原与牧草） 1998年第1期 20-25页

作者： pi.rre c.v.dutoit 文亦芾

对实际放牧率与绵羊采食各种干燥台地灌木茎的程度之间的关系进行了研究。南非干燥台地的农户与研究人员中有一个经验原则,即绵羊采食灌木的直径接近或小于2mm。这项假设已经历了3年的检验。对Pentzia spinescens和Rosenia humillis这... 详细信息

对实际放牧率与绵羊采食各种干燥台地灌木茎的程度之间的关系进行了研究。南非干燥台地的农户与研究人员中有一个经验原则,即绵羊采食灌木的直径接近或小于2mm。这项假设已经历了3年的检验。对Pentzia spinescens和Rosenia humillis这两种最常见牧草品种,用游标卡尺测量了它们的新近被采食的茎直径。在估计现有载畜量时所使用的可食干物质的估计值是将刈割后的干物质分成可食与不可食物质两类为基础的。此分类标准为2mm。关于绵羊自由采食直径高达2mm的茎干的假设是不成立的。适口性差的品种其采食茎直径很少达到2mm,而适口性好的品种其采食茎直径通常高于5mm。已证明适口性差的品种被绵羊采食的茎直径平均为1.4～1.6mm。这个结果直接影响了估计干物质量来估算载畜量的方法。这个地区长期载畜量额定值为30hm^2/大家畜单位;基于放牧率试验所得的每公顷净收益资料,求得载畜量为33.4hm^2/大家畜单位。放牧率与被采食茎直径的关系求得的最佳载畜量为32.5hm^2/大家畜单位。这表明,通过检测被采食特定种的茎直径,可以确定载畜量范围或调整放牧率。

关键词：实际放牧率最佳放牧率干燥台地灌木南非

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Anisotropic etching mechanisms of 4H-Sic:Experimental and first-principles insights

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Journal of Semiconductors 2024年第1期45卷 42-47页

作者： Guang Yang Lingbo Xu can cui Xiaodong pi Deren Yang Rong Wang Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of PhysicsZhejiang Sci-Tech UniversityHangzhou 310018China State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Institute of Advanced Semiconductors&Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices HangzhoIun novation CenterZhejiang UniversityHangzhou 311200China

Molten-alkali etching has been widely used to reveal dislocations in 4H silicon carbide(4H-Sic),which has promoted the identification and statistics of dislocation density in 4H-Sic single ***,the etching mechanism of 4H-Sic is limited *** this letter,we reveal the anisotropic etching mechanism of the Si face and c face of 4H-Sic by combining molten-KOH etching,X-ray photoelectron spectroscopy(XPS)and first-principles *** activation energies for the molten-KOH etching of the c face and Si face of 4H-Sic are calculated to be 25.09 and 35.75 kcal/mol,*** molten-KOH etching rate of the c face is higher than the Si *** XPS analysis and first-principles calculations,we find that the molten-KOH etching of 4H-Sic is proceeded by the cycling of the oxidation of 4H-Sic by the dissolved oxygen and the removal of oxides by molten *** faster etching rate of the c face is caused by the fact that the oxides on the c face are unstable,and easier to be removed with molten alkali,rather than the c face being easier to be oxidized.

关键词： principles alkali etching

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clinical and demographic features of patients undergoing videocapsule endoscopy management:A descriptive study

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World Journal of Gastrointestinal Endoscopy 2024年第7期16卷 424-431页

作者： María c Mejía Luis G piñeros Luis M Pombo Laura A León Jenny A velásquez Aníbal A Teherán Karen P Ayala Research center Fundación Universitaria Juan N.CorpasBogotá111321Colombia Fundación Universitaria Juan N.corpas Bogotá111321Colombia Department of Gastroenterology Universidad Militar Nueva GranadaBogotá111711Colombia Department of Gastroenterology Hospital Universitario Clínica San RafaelBogotá111711Colombia

BAcKGROUND video-capsule endoscopy(vcE)is an efficient tool that has proven to be highly useful in approaching several gastrointestinal *** was implemented in colombia in 2003,however current characterization of patients undergoing vcE in colombia is limited,and mainly comes from two investigations conducted before the SARS-cov-2 pandemic *** To describe the characteristics of patients undergoing vcEs and establish the main indications,findings,technical limitations,and other outstanding *** A descriptive study was carried out using data from reports of vcE(pillcam SB3 system)use in a Gastroenterology Unit in Bogotá,colombia between September 2019 and January *** and clinical variables such as indication for the vcE,gastric and small bowel transit times(GTT,SBTT),endoscopic preparation quality,and limitations were described[n(%),median(IQR)].RESULTS A total of 133 vcE reports were *** were in men with a median age of 70 *** majority had good preparation(96.2%),and there were technical limitations in 15.8%of *** main indications were unexplained anemia(91%)or occult bleeding(23.3%).The median GTT and SBTT were 14 and 30 minutes,*** frequencies of bleeding stigma(3.79%)and active bleeding(9.09%)were low,and the most frequent abnormal findings were red spots(28.3%),erosions(17.6%),and vascular ectasias(12.5%).cONcLUSION vcE showed high-level *** main indication was unexplained *** bleeding was the most frequent *** with artificial intelligence,vcE can improve diagnostic precision and targeted therapeutic interventions.

关键词： Endoscopy video-capsule endoscopy capsule endoscopy Gastrointestinal diseases Observational study Gastrointestinal bleeding

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Biomaterial engineering strategies for modeling the Bruch's membrane in age-related macular degeneration

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Neural Regeneration Research 2024年第12期19卷 2626-2636页

作者： Blanca Molins Andrea Rodríguez víctor Llorenç Alfredo Adán Group of Ocular Inflammation:clinical and Experimental Studies Institut d’Investigacions Biomèdiques AgustíPi I Sunyer(IDIBAPS)BarcelonaSpain Institut clínic d’Oftalmologia(IcOF) Hospital Clínic BarcelonaSpain

Age-related macular degeneration,a multifactorial inflammatory degenerative retinal disease,ranks as the leading cause of blindness in the ***,there is a scarcity of curative therapies,especially for the atrophic advanced form of age-related macular degeneration,likely due to the lack of models able to fully recapitulate the native structure of the outer blood retinal barrier,the prime to rget tissue of age-related macular *** in vitro systems rely on 2D monocultures unable to adequately reproduce the structure and function of the outer blood retinal barrier,integrated by the dynamic interaction of the retinal pigment epithelium,the Bruch's membrane,and the underlying *** Bruch's membrane provides structu ral and mechanical support and regulates the molecular trafficking in the outer blood retinal barrier,and therefo re adequate Bruch's membrane-mimics are key for the development of physiologically relevant models of the outer blood retinal barrie *** the last years,advances in the field of biomaterial engineering have provided novel approaches to mimic the Bruch's membrane from a variety of *** review provides a discussion of the integrated properties and function of outer blood retinal barrier components in healt hy and age-related macular degeneration status to understand the requirements to adequately fabricate Bruch's membrane biomimetic ***,we discuss novel materials and techniques to fabricate Bruch's membrane-like scaffolds for age-related macular degeneration in vitro modeling,discussing their advantages and challenges with a special focus on the potential of Bruch's membrane-like mimics based on decellularized tissue.

关键词： age-related macular degeneration Bruch's membrane decellularization retinal pigment epithelium scaffold

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clinical profile and outcomes in very elderly patients with atrial fibrillation anticoagulated with rivaroxaban: data from the EMIR study

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Journal of Geriatric cardiology 2024年第7期21卷 723-732页

作者： Francisco Marín Manuel Anguita Sánchez Iñaki Lekuona Marcelo Sanmartín Fernán-dez vivencio Barrios carlos Perez Muñoz Juan cosín-Sales Alejandro IPérez cabeza vanesa Roldán Schilling carles Rafols Priu Esteban Orenes-piñero María Asunción Es-teve-Pastor Department of cardiology Hospital Clínico Universitario Virgen de la ArrixacaIMIB-ArrixacaUniversity of MurciaCIBERCVMurciaSpain Department of cardiology Hospital Reina Sofía CórdobaIMIBICUniversity of CordobaCIBERCVCórdobaSpain Hospital Galdakao-Usansolo BizkaiaSpain Department of cardiology Hospital Uni-versitario Ramony CajalCIBERCVMadridSpain Department of cardiology University Hospital Ramóny CajalAl-caláUniversityMadridSpain Medical center La capillita Sanlúcar de Barrameda.Private cardiology clinicJerez de la FronteraSpain Department of cardiology Hospital Arnau de VilanovaValenciaSpain Department of car-diology Virgen de la Victoria University HospitalCIBERCV.MalagaSpain Department of Haematology Hospital Clínico Universitario Virgen de la ArrixacaUniversity of MurciaMurciaSpain Department of Medical Affairs Bayer HispaniaBarcelonaSpain Department of Biochemistry and Molecular Biology-A University of MurciaMurciaSpain

Objectives To analyze the clinical profile,adequacy of treatment with rivaroxaban and outcomes in octogenarians with atrial fibrillation(AF),taking rivaroxaban in clinical *** Observational and non-interventional study that included AF adults recruited from 79 Spanish centers,anticoagulated with rivaroxaban ≥ 6 months before being *** were analyzed according to age(≥ 80 vs.ctogenarians at *** to younger patients,octogenarians had more comorbidities,higher cHA2DS2-vASc(4.5 ± 1.3 vs.3.0 ± 1.4;P cores(2.0 ± 1.0 vs.1.4 ± 1.0;P verall,the dose of rivaroxaban was adequately prescribed in 83.4% of patients,but more frequently in the younger population(71.1% vs.89.1%;P = 0.039).After a mean follow-up of 2.2 ± 0.6 years,annual rates of stroke + systemic embolism + transient ischemic attack,MAcE,cardiovascular death and major bleeding were 1.03%,1.24%,1.03% and 1.75%,respectively,in octogenarian *** for progressive heart failure death and major bleeding,rates of outcomes in octogenarians were similar compared to younger *** octogenarians,the concomitant use of antiplatelet agents and non-severe dementia were independently associated with the development of ischemic stroke,whereas previous coronary revascularization and heart failure with MAcE,and higher HAS-BLED score with major *** In clinical practice,around one third of patients taking rivaroxaban are *** patients have many comorbidities and a high thromboembolic *** that,rates of adverse events remain *** is adequately prescribed in the majority of octogenarians.

关键词： patients atrial bleeding

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Myelin histology:a key tool in nervous system research

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Neural Regeneration Research 2024年第2期19卷 277-281页

作者： Óscar Darío García-García víctor carriel Jesús chato-Astrain Department of Histology Tissue Engineering GroupUniversity of Granada&Instituto de Investigación Biosanitaria ibs.GRANADAGranadaSpain

The myelin sheath is a lipoprotein-rich,multilayered structure capable of increasing conduction velocity in central and peripheral myelinated nerve *** to the complex structure and composition of myelin,various histological techniques have been developed over the centuries to evaluate myelin under normal,pathological or experimental ***,methods to assess myelin integrity or content are key tools in both clinical diagnosis and neuroscience *** this review,we provide an updated summary of the composition and structure of the myelin sheath and discuss some histological procedures,from tissue fixation and processing techniques to the most used and practical myelin histological staining *** the lipoprotein nature of myelin,the main features and technical details of the different available methods that can be used to evaluate the lipid or protein components of myelin are described,as well as the precise ultrastructural techniques.

关键词： fluorescence microscopy histology light microscopy lipid histochemistry metallographic techniques myelin histochemistry myelin immunohistochemistry myelin structure&composition myelin ultrastructural evaluation tissue fixation&processing

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广西东平锰矿床地质地球化学特征及矿床成因

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地球科学 2024年第2期49卷 656-668页

作者：周皓宇皮道会黄钦丁大庆凌泽安徽省地质矿产勘查局313地质队安徽六安237010 中国地质大学资源学院湖北武汉430074 中国冶金地质总局广西地质勘查院广西南宁530022 中国冶金地质总局矿产资源研究院北京101300 辽宁省第四地质大队有限责任公司辽宁阜新123000

三叠纪是中国南方一个最重要的成锰时代,在华南板块和周围赋存许多大中型的锰矿床.东平锰矿位于中国广西桂西南成矿带.以东平锰矿为研究对象,通过显微薄片观察、电子探针分析及全岩地球化学分析等方法,探讨了锰矿的物质来源和矿床成因.... 详细信息

三叠纪是中国南方一个最重要的成锰时代,在华南板块和周围赋存许多大中型的锰矿床.东平锰矿位于中国广西桂西南成矿带.以东平锰矿为研究对象,通过显微薄片观察、电子探针分析及全岩地球化学分析等方法,探讨了锰矿的物质来源和矿床成因.通过矿相学的研究工作,我们发现东平锰矿里广泛赋存有黄铁矿、黄铜矿、闪锌矿、方铅矿、辉砷钴矿、硫镍钴矿等一些硫或砷化物.锰矿石样品中Al/(Al+Fe+Mn)、Y/Ho比值和Fe-Mn-(Ni+cu+co)×10、lgU-lgTh投图等表明锰矿的成矿物质来源与热水活动有关;正ce异常及v/(v+Ni)等指示锰最初是在氧化环境中富集.综合以上研究,我们认为东平锰矿的锰质来源主要与热液活动有关;热液来源的锰最初以氧化物或者氢氧化物的方式沉淀,在成岩过程中转变为锰碳酸盐.

关键词：东平锰矿床地球化学物质来源成矿模式

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基于分段结构局部特征尺度分解的轴承内圈故障识别

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机械管理开发 2024年第6期39卷 114-115,118页

作者：皮杨勇内江职业技术学院智能制造与汽车学院四川内江641100

为了提高轴承振动信号特征提取能力,设计了一种分段结构局部特征尺度分解(PPLcD)方法。根据峭度与相关系数的指标性能,构建了一种峭度-相关系数(K-c)权重评价指标。选择cWRU轴承参数作为测试对象,搭建测试平台。研究结果表明:内圈信号... 详细信息

为了提高轴承振动信号特征提取能力,设计了一种分段结构局部特征尺度分解(PPLcD)方法。根据峭度与相关系数的指标性能,构建了一种峭度-相关系数(K-c)权重评价指标。选择cWRU轴承参数作为测试对象,搭建测试平台。研究结果表明:内圈信号故障分析发现,以PPLcD分解获得的有效分量达到了更小MAE与RMSE,同时形成了更大的相关系数,该结果与外圈故障相同。采用PPLcD分解的方法可以获得比初始LcD更优的性能。该研究可以拓展到其他的机械传动领域,具有很大的推广价值。

关键词：轴承故障特征提取故障诊断分段结构

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