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A unified model for ductile-to-brittle transition in body-centered cubic metals

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Journal of Materials Science & Technology 2023年第10期141卷 193-198页

作者： Yu-Heng Zhang En Ma Jun Sun wei-zhong han State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

Ductile-to-brittle transition(DBT)is a well-known phenomenon in body-centered-cubic(BCC)metals,in-termetallics and semiconductor materials.A quantitative prediction of the DBT temperature,however,has so far remained ***,we propose a unified model based on the efficacy of dislocation multi-plication as the controlling factor for DBT,with the dislocation source efficiency governed by the relative mobility of screw versus edge *** model successfully predicts the DBT temperature of iron,molybdenum and tungsten,and also covers the influence of grain size,initial dislocation density,and the multiplicity of dislocation sources.A comparison with experiments indicates that the model captures the key DBT features,providing new insight into the toughness of BCC metals.

关键词： Metals Ductile Brittle Dislocation Mobility

Annealing cracking in Zr and a Zr-alloy with low hydrogen concentration

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Journal of Materials Science & Technology 2024年第15期182卷 165-175页

作者： Xi-Heng Lin Irene J.Beyerlein wei-zhong han Center for Advancing Materials Performance from the Nanoscale State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Materials Department University of CaliforniaSanta BarbaraCA 93106-5070USA Department of Mechanical Engineering University of CaliforniaSanta BarbaraCA 93106-5070USA

Hydrogen embrittlement,also known as hydrogen-induced cracking,is a longstanding concern for zirco-nium(Zr)and its *** affinity for hydrogen in zirconium results in the formation of brittle *** are conventionally thought to facilitate crack propagation,and the prevailing recommendation to hinder hydride embrittlement involves reducing the hydrogen concentration in the material and ap-plying slow cooling to reduce thermal ***,in Zr with a maximum hydrogen concentration of 43 wppm,we show that cracks initiate unexpectedly after annealing,a step that involves slow cooling and no external *** a suite of high-resolution microscopy,we show that annealing cracks initiate at prismaticδ-hydrides,whose presence is *** microscopic annealing crack paths are conse-quently crystallographic,following the habit plane of these prismaticδ-*** commonly reportedγ-hydride andδ-hydrides that develop on the basal plane are found not to initiate *** rationalize that prismaticδhydrides result from the intergranular thermal residual stresses that develop during slow *** finding of uncommon annealing cracking further advances the mechanistic understanding of hydride embrittlement in zirconium and can lead to new strategies for design and fabrication of advanced zirconium alloys for harsh environments.

关键词： Zirconium Hydride Cracking Habit plane Reorientation

Transmission electron microscopy characterization of dislocation loops in irradiated zirconium

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Tungsten 2021年第4期3卷 470-481页

作者： Si-Mian Liu wei-zhong han Center for Advancing Materials Performance from the Nanoscale State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China

Characterization of irradiation defects is of great importanceto mitigate irradiation damage,reduce irradiation growth and tune mechanical properties in Zr ***,we describe a practical method to characterize the dislocation loops in irradiated Zr using conventional transmission electron microscopy(TEM).Vacancy or interstitial nature of dislocation loops is determined using the inside and outside contrast *** habit plane of dislocation loops is determined by tilting the sample to multiple zone axes and judged based on the projected loop *** size ofloops is measured by tilting the sample to an edge-on position and the loop number is counted under a weak-beam dark-field TEM condition.loops have a line contrast under viewing direction of a-axis and a circular shape under viewing direction of *** addition,a large number of triangle-shaped vacancy platelets(TVPs)were formed on the basal *** increasing the irradiation damage from 0.5 to 1.5 dpa,the number density ofloops keeps constant,while the number density of TVPs increased significantly,owing to the anisotropic diffusion and accumulation of point defects within basal *** methods introduced here are easy to follow and extend into other related investigations.

关键词： Irradiation damage Dislocation loop Habit plane Zirconium alloys

Efficacy and economic benefits of a modified Valsalva maneuver in patients with paroxysmal supraventricular tachycardia

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World Journal of Clinical Cases 2020年第23期8卷 5999-6008页

作者： wei Wang Teng-Fei Jiang wei-zhong han Lin Jin Xiao-Jing Zhao Ying Guo Internal Medicine-Cardiovascular Department Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina Department of Nursing The First Affiliated Hospital of Shandong First Medical University Department of Nursing Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina

BACKGROUND A modified Valsalva maneuver(VM)has been suggested to be superior to the standard VM for conversion of paroxysmal supraventricular tachycardia(PSVT).AIM To evaluate the efficacy and economic benefits of a modified VM in Chinese *** Patients with PSVT admitted to our center between October 2017 and September 2019 were randomly assigned to the modified and standard VM *** via VM was performed up to three *** primary outcome of the study was the success rate of PSVT conversion to sinus *** secondary outcomes included the incidence of adverse events,economic cost during the visit,and the degree of patient acceptance of the *** Overall,361 patients were enrolled,with 180 allocated to the modified VM group and 181 to the standard VM *** characteristics were well matched in the ***,the modified VM group had higher success rates of PSVT conversion after single(47.78%vs 15.38%,P0.05).Moreover,the economic cost of the clinic visit was significantly lower for the modified VM group than for the standard VM group(P<0.05).CONCLUSION The modified VM may confer both therapeutic and economic benefits as compared with the standard VM for conversion of PSVT.

关键词： Paroxysmal supraventricular tachycardia Modified Valsalva maneuver Costeffective analysis

Spermatozoal protein profiles in male infertility with asthenozoospermia

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Chinese Medical Journal 2010年第20期123卷 2879-2882页

作者： LI Hong-ju YU Ning ZhanG Xin-yu JIN wei LI han-zhong Department of Urology Peking Union Medical College Hospital Chinese Academy of Medical Sciences Beijing 100730 China

Background Infertility is a major medical and social problem, and elementary research on the spermatozoal proteins and their functions are relatively scarce and there are very few confirmed and effective options for the treatment of male infertility. Thus, it is essential to find candidate proteins that affect male infertility. This study was designed to detect the proteins with differential expression in sperm from infertile patients and normal *** Semen samples from patients with idiopathic asthenozoospermia （n=114） and from fertile men with normal spermiograms （n=37） were collected. Semen sample analysis, sperm protein extraction, SDS-PAGE electrophoresis and Western blotting analysis were performed. Results were analyzed by SPSS 16.0 statistical *** Western blotting analysis of spermatic proteins displayed a major differentially expressed protein in spermatozoa from fertile and idiopathic asthenozoospermia patients. Densities and volumes of the identified protein in the patients were significantly decreased compared to normal donors （P=0.034 and P=0.036, respectively）. The protein was identified as DEAD-box protein 4 （DDX4, VASA）. The expression and correction value （CV） of DDX4/VASA in the patients was reduced significantly compared to normal donors （P=0.037 and P=0.031, respectively）.Conclusions The expression of spermatic protein DDX4/VASA associates with spermatic motility, implying that DDX4NASA may be a candidate marker for evaluation of spermatic motility.

关键词： male infertility asthenozoospermia proteomics

Overview of Camera Calibration

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科技信息 2013年第7期 293-295页

作者： YANG Fei ZhanG wei-zhong han Wen-xi ZhanG Feng College of Information Engineering Qingdao University Qingdao Shandong 266071

This paper introduce several commonly used camera calibration method include their advantages and *** traditional methods of camera calibration need to know precise structural information of calibration object and they are *** calibration based on active vision get the camera calibration through the controlling of some parameters of ***-calibration of camera don't need to use the calibration block and get the camera calibration through the corresponding relationship among multiple images.

关键词：英语学习学习方法阅读知识阅读材料

Transumbilical single-port laparoscopic cholecystectomy： a case report

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Chinese Medical Journal 2008年第23期121卷 2463-2464页

作者： GUO wei ZhanG zhong-tao han wei LI Jian-she JIN Lan LIU Jun ZHAO Xiao-mu WANG Yu Department of General Surgery Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Recently, scarless surgery has become a widely used surgical technique, which has made considerable progress owing to extensive animal model studies and clinical trials. Here, we report the first case of transumbilica... 详细信息

关键词： laparoscopic cholecystectomy clinical trials mainland China animal model

Brain region-specific roles of brain-derived neurotrophic factor in social stress-induced depressive-like behavior

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Neural Regeneration Research 2025年第1期20卷 159-173页

作者： Man han Deyang Zeng wei Tan Xingxing Chen Shuyuan Bai Qiong Wu Yushan Chen Zhen wei Yufei Mei Yan Zeng Brain Science and Advanced Technology Institute Wuhan University of Science and TechnologyWuhanHubei ProvinceChina Geriatric Hospital Affiliated to Wuhan University of Science and Technology WuhanHubei ProvinceChina School of Public Health Wuhan University of Science and TechnologyWuhanHubei ProvinceChina

Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral *** studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and *** how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress *** this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of *** focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine *** determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic ***,BDNF might be a biological indicator regulating stress-related processes in various brain regions.

关键词： amygdala chronic mild stress chronic social defeat stress corticolimbic system depression hippocampus medial prefrontal cortex nucleus accumbens social stress models ventral tegmental area

家兔中脑导水管周围灰质中注射八肽胆囊收缩素(CCK-8)拮抗吗啡镇痛和电针镇痛

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生理学报 1989年第4期41卷 388-394页

作者：曹威周仲福韩济生北京医科大学生理教研室

家兔单侧PAG内注射CCK-83ng,能使静脉注射4mg/kg吗啡引起的镇痛作用降低73％或使电针镇痛效果降低67％。在1.5—6.0ng范围内呈量效关系。无硫的CCK-8无此作用。PAG内注射CCK受体拮抗剂proglumide 4μg可翻转CCK-8的抗吗啡镇痛作用。说明... 详细信息

家兔单侧PAG内注射CCK-83ng,能使静脉注射4mg/kg吗啡引起的镇痛作用降低73％或使电针镇痛效果降低67％。在1.5—6.0ng范围内呈量效关系。无硫的CCK-8无此作用。PAG内注射CCK受体拮抗剂proglumide 4μg可翻转CCK-8的抗吗啡镇痛作用。说明PAG部位注射外源性CCK-8可通过CCK受体对抗阿片镇痛。 PAG内注射CCK-8抗血清可显著增强静脉注射2mg/kg吗啡的镇痛效果。PAG内注射CCK抗血清本身也能引起痛阈轻度升高。说明PAG内有内源性的CCK-8发挥紧张性的抗阿片镇痛作用。

关键词： CCK-8 止痛吗啡电针