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Ⅳ型储氢气瓶内衬材料聚酰胺6氢渗透行为的分子模拟研究

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中国塑料 2024年第8期38卷 62-68页

作者：张学敏翟丽珍李厚补齐国权黄尚彬张冬娜杨志锋张晓宇长安大学材料科学与工程学院西安710064 中国石油集团工程材料研究院有限公司石油管材及装备材料服役行为与结构安全国家重点实验室西安710077 宝鸡天联汇通复合材料有限公司陕西宝鸡712013

采用分子模拟方法,在不同温度(30、40、60、80℃)和压力(82、87.5、98、103 MPa)条件下,研究氢气在聚合物材料聚酰胺6(PA6)中的渗透性,并分析了氢气的渗透机理。结果表明,温度升高时,吸附热和自由体积分数逐渐增加,热运动加剧,分子运动... 详细信息

采用分子模拟方法,在不同温度(30、40、60、80℃)和压力(82、87.5、98、103 MPa)条件下,研究氢气在聚合物材料聚酰胺6(PA6)中的渗透性,并分析了氢气的渗透机理。结果表明,温度升高时,吸附热和自由体积分数逐渐增加,热运动加剧,分子运动空间增大,氢气在PA6中的溶解度系数、扩散系数以及渗透系数均呈增大趋势。在压力为103 MPa时,升高温度对渗透系数的影响最大,增加了88.3%。随着压力增大,氢气与PA6分子链之间的相互作用减小,自由体积分数减小,所以氢气在PA6中的溶解度系数、扩散系数以及渗透系数均呈下降趋势。在温度为60℃时,压力对渗透系数影响最显著,降低了38.6%。氢气在PA6中的渗透机理包括在低势能区的聚集性吸附过程,和在自由体积处形成的空穴内振动-空穴间跃迁的扩散过程,温度升高时,氢气分子运动变得活跃,有更多的空穴间跳跃次数,压力升高时,变化相反。

关键词：聚酰胺6 氢气扩散吸附渗透分子模拟

Effects of different cue positions on evoked potentials in the cerebral cortex during global and local processing of compound stimuli A study of event-related potential

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Neural Regeneration Research 2009年第11期4卷 941-946页

作者： xuemin zhang Yongna LiO Siyu Bai Yaqin Zheng School of Psychology State Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing 100875 China Department of Psychology New York State University Albany 12246 New York USA Department of Educational Psychology Xuchang University Xuchang 461000 Henan Province China

BACKGROUND： Previous studies of attentional control have focused primarily on pre-cue control of attentional cue and direction. OBJECTIVE： To measure the differences in electrical activity of brain cells while processing pre-cue and post-cue compound stimuli, and to explore brain electrical activity during global and local processing of compound stimuli according to electroencephalogram （EEG） recordings. DESIGN, TIME AND SETTING： A within-subject design study was performed at the School of Psychology, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, China from March to May 2006. PARTICIPANTS： A total of 30 healthy, undergraduate students, aged 17-24 years, comprising 12 males and 18 females, were voluntarily enrolled from Beijing Normal University. Subjects exhibited normal or corrected-to-normal visual acuity. No significant non signal wave drift was detected during testing. METHODS： A total of 30 subjects were subjected to pre-cue and post-cue compound stimulus processing using event-related potential and EEG recordings. MAIN OUTCOME MEASURES： Evoked potential was recorded in different brain regions utilizing event-related potential to observe hemispheric symmetry, cue consistency and global-local features. RESULTS： Pre-cue compound stimuli resulted in hemispheric asymmetry for early wave （N1） and late wave （P3） in anterior brain regions. Early- and late-wave induced hemispheric asymmetry for electrode points （O1, 02, P3, P4, Pz, F3, F4, F7, F8, Fz, FP1, FP2, T7, TS, C3, C4, and Cz） during processing of pre-cue compound stimuli （P 〈 0.05）. Post-cue compound stimuli did not induce hemispheric asymmetry of brain waves induced by the above-described electrode points. No significant differences in global and local responses were determined during processing of post-cue compound stimuli. Under pre-cue conditions, significant differences were observed in N1 and P3 in the above-mentioned electrode points （P 〈 0.05）. However, under p

关键词： compound stimuli cue event-related potential hemispheric symmetry attention

虚拟仿真技术联合雨课堂在肠造口护理实践教学中的应用

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护理学杂志 2024年第2期39卷 83-86页

作者：王颖田建丽焦亚辉张学敏张荣薛茹田伶玉承德医学院护理学院河北承德067000 承德医学院附属医院胃肠外科

目的探索虚拟仿真技术联合雨课堂在肠造口护理实践教学中的应用效果,为提升护理实践教学质量提供参考。方法将2020级护理本科三年级2个自然班的学生随机分为对照组(n=37)与试验组(n=36)。对照组采用传统实践教学模式,即教师示教、学生... 详细信息

目的探索虚拟仿真技术联合雨课堂在肠造口护理实践教学中的应用效果,为提升护理实践教学质量提供参考。方法将2020级护理本科三年级2个自然班的学生随机分为对照组(n=37)与试验组(n=36)。对照组采用传统实践教学模式,即教师示教、学生练习、教师巡回、学生反示,试验组采用虚拟仿真技术联合雨课堂教学模式。教学后比较两组理论及操作考核成绩,并进行教学效果评价。结果教学后试验组理论及操作考核成绩显著高于对照组(均P<0.05),70%以上的试验组学生认可虚拟仿真技术联合雨课堂教学模式,充分肯定教学效果。结论虚拟仿真技术联合雨课堂有利于加强学生自主学习能力、激发学习兴趣、培养临床思维,可有效提高肠造口护理实践教学质量。

关键词：肠造口虚拟现实虚拟仿真系统雨课堂案例教学教学质量护理教学

Microstructure and Mechanical Properties of a Spray-Formed Superalloy

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Acta Metallurgica Sinica(English Letters) 2014年第6期27卷 1063-1069页

作者： Fuwei Kang Fuyang Cao xuemin zhang Hongyan Yue Yicheng Feng School of Materials Science and Engineering Harbin University of Science and Technology School of Materials Science and Engineering Harbin Institute of Technology

The microstructural evolution and mechanical properties of a spray-formed superalloy were studied in this paper. Based on a better understanding of the microstructural evolution of the spray-formed superalloy during solution treatment, an optimum solution treatment process was obtained, namely, at 1,140 °C for 6 h, and air cooling（AC）. The effects of the ageing treatments on the mechanical properties of the post-solution-treated spray-formed superalloy were evaluated using ageing harden curves and tensile testing. The results indicated that the maximum hardness value was achieved at 850 °C for 8 h, AC. Due to co-precipitation of primary and secondary c0 precipitates during the heat treatment,the spray-formed superalloy obtained an excellent combination of yield strength（YS = 1,110 MPa）, ultimate tensile strength（UTS = 1,503 MPa）, ductility（elongation, EL = 21%） and excellent stress rupture properties at 650 °C（UTS = 1,209 MPa, EL = 15.8%）. The heat treatment also improved the rupture life at 650 °C/950 MPa and 750 °C/539 MPa up to 140 h without rupturing. The tensile-fractured surfaces exhibit ductile transgranular failure feature. The optimum heat treatment process was determined to be 1,140 °C/6 h＋850 °C/8 h＋AC.

关键词： Spray-formed superalloy Microstructure Ageing harden Mechanical properties

Components and sequential changes in event-related potential induced by gaze orientation processing under a reflective attention cue paradigm

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Neural Regeneration Research 2010年第19期5卷 1475-1479页

作者： Yingdi Li xuemin zhang Yan Song Qing Feng School of Psychology Beijing Normal University State Key Laboratory of Cognitive Neuroscience and Learning Beijing 100875 China Xiamen Haicang Occupational Middle School Xiamen 361012 Fujian Province China

Gaze orientation induces activation of relevant brain regions, presents differences in specificity and time course, and is exhibited in patients with brain injury. However, the components of activated event-related potential remain controversial. Previous studies of behavior and cognitive neuroscience related to gaze orientation investigated conscious attention of visual orientation. The present study explored gaze orientation processing-induced event-related potential components and changes with time using reflective orientation of visual attention under a reflective attention cue paradigm. Visual attention processing of gaze orientation was recorded using event-related potential and electroencephalographic recording. Results demonstrated that the reflective attention cue task evoked early directing attention negativity and anterior directing attention negativity, but did not trigger late directing attention positivity. These results suggest that reflective attention occurs over a short time of visual stimulus presentation. During the early stage of attention processing, early directing attention negativity and anterior directing attention negativity were detected, but late directing attention positivity did not occur. These results confirmed reflectivity and time-course superiority of gaze orientation attention processing.

关键词： gaze direction cue validity event-related potential hemisphere superiority reflective attention cognitive neuroscience

睡眠剥夺对幼鼠小脑沉默信息调节因子6表达的影响

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中华麻醉学杂志 2024年第1期44卷 41-45页

作者：肖岚高尘怡陈婷张学敏钟琦曹玥唐李娟陈畅张宗泽武汉大学中南医院麻醉科武汉430071

目的评价睡眠剥夺对幼鼠小脑沉默信息调节因子6(SIRT6)表达的影响。方法SPF级健康雄性C57BL/6小鼠50只,4周龄,体质量14~16 g,采用随机数字表法分为2组(n=25):对照组(Con组)和睡眠剥夺组(SD组)。采用多平台水环境法制备小鼠睡眠剥夺模型... 详细信息

目的评价睡眠剥夺对幼鼠小脑沉默信息调节因子6(SIRT6)表达的影响。方法SPF级健康雄性C57BL/6小鼠50只,4周龄,体质量14~16 g,采用随机数字表法分为2组(n=25):对照组(Con组)和睡眠剥夺组(SD组)。采用多平台水环境法制备小鼠睡眠剥夺模型,每天睡眠剥夺20 h,连续10 d。睡眠剥夺后行平衡木实验检测小鼠平衡和协调能力,麻醉后处死小鼠,取小脑组织,透射电子显微镜观察超微结构,采用高尔基染色法测定小脑浦肯野细胞树突棘密度,采用免疫荧光法检测小脑浦肯野细胞SIRT6和钙结合蛋白D-28k(CbD-28k)共表达情况,检测小脑葡萄糖转运体3(Glut3)表达。结果与Con组比较,SD组小鼠平衡木通过时间延长,后足滑脱次数增加,小脑4-6cb神经元突触间隙增大,突触后致密物厚度、浦肯野细胞树突棘密度及SIRT6与CbD-28k共表达阳性细胞数降低,Glut3表达下调(P<0.05)。结论睡眠剥夺降低幼鼠平衡和协调能力的机制与下调小脑浦肯野细胞SIRT6表达,降低神经元糖代谢,从而损伤小脑突触可塑性有关。

关键词：睡眠剥夺小脑沉默信息调节因子6

三维打印模具辅助以问题为基础教学法对住院医师批判性思维能力的影响

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中国高等医学教育 2024年第2期 107-109页

作者：吕杰张韬张学民李伟浩张小明北京大学人民医院北京100044

目的:探讨三维打印模具辅助以问题为基础教学法(PBL-3DM)对住院医师批判性思维(CT)能力的影响。方法:选取我院专科住院医师37人进行PBL-3DM教学并调研教学前后CT变化。结果:教学前对象CTDI-CV值为(228.38±5.30)分,83.8%对象CT未达正性,... 详细信息

目的:探讨三维打印模具辅助以问题为基础教学法(PBL-3DM)对住院医师批判性思维(CT)能力的影响。方法:选取我院专科住院医师37人进行PBL-3DM教学并调研教学前后CT变化。结果:教学前对象CTDI-CV值为(228.38±5.30)分,83.8%对象CT未达正性,24.3%没有CT,7个维度能力均欠佳。教学2周4周和12周后的CTDI-CV逐升为(245.40±5.32)分、(278.29±6.28)分和(326.46±3.37)分,负性CT比例降到27.0%无CT比例为0%;12周时除分析能力和认知成熟度,各维度评分均显著提高(P<0.05)。研究生医师负性比例最高(35.1%),规培医师比例最低(21.6%),培训后改善最明显的是研究生医师,进修医师改善度最低。结论:PBL-3DM教学法有助于提升不同背景住院医师的批判性思维能力。

关键词：以问题为基础的教学法三维打印模具批判性思维医学教育

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Deep vein thrombosis in early pregnancy:A retrospective study

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Gynecology and Obstetrics Clinical Medicine 2023年第1期3卷 44-50页

作者： Chen zhang xuemin zhang Guoli Liu Department of Obstetrics and Gynecology Peking University People’s HospitalBeijing100044China Department of Vascular Surgery Peking University People’s HospitalBeijing100044China

Objective:To investigate the clinical characteristics,management,and prognosis of deep vein thrombosis(DVT)during early ***:We conducted a retrospective study among women with DVT during their first trimester of pregnancy who were admitted to the obstetrics department of Peking University People's Hospital between March 2008 and May *** analyzed clinical data of eight patients,including their general condition,obstetric characteristics,diagnosis,treatment,and gestational ***:Risk factors for DVT in the first trimester included personal history of DVT,thrombophilia and immune diseases,and DVT was more likely to affect the left *** main manifestation of DVT was pain or swelling of the affected limbs.D-dimer levels after anticoagulant treatment showed a downward trend compared with those before treatment(P=0.09),while D-dimer levels increased significantly after delivery compared with those before delivery(P=0.03).All the patients started on low-molecular-weight heparin(LMWH)therapy after a diagnosis of *** inferior vena cava(IVC)filters were implanted in 3 patients with mixed thrombosis before delivery,but were removed after the *** for 1 case with thrombophilia who refused treatment,others underwent anticoagulation therapy from 6 weeks to 1 year *** patients achieved a successful delivery with live ***:During early pregnancy,DVT was more common in women with maternal risk *** cases of venous thromboembolism(VTE)were observed in the left *** women with a high risk of DVT,medical intervention,early identification,accurate diagnosis and precise treatment during early pregnancy should be promoted.

关键词： Early pregnancy Deep vein thrombosis Clinical characteristics Diagnosis Treatment Prognosis

Grouting-induced ground heave and building damage in tunnel construction:A case study of Shenzhen metro

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Underground Space 2022年第6期7卷 1175-1191页

作者： Zonglei Dong xuemin zhang Chenxi Tong Xinlei Chen Han Feng Sheng zhang School of Civil Engineering Central South UniversityChangsha 410075China

This paper presents a case study of the grouting-induced ground heave and building damage in the tunnel construction of Shenzhen Metro Line 10,which passes through a crowded urban area with water-rich strata in Shenzhen,the province of Guangdong,*** was reported that the ground surface heave of up to approximately 500 mm was observed,and the customs building above the tunnels was seriously damaged because of a 200 mm *** a significant heave was closely associated with the advanced curtain grouting adopted in the tunnel *** this end,the heave of the ground surface and the displacement and deformation of the customs building were *** discrete element method(DEM)was then used to qualitatively analyze the relations between the grouting parameters and the ground *** results demonstrated that the poor dewatering work in the early stages increased the difficulty of *** grouting materials with high viscosity and large grouting pressure were required for water blocking because of the large amount of confined water in the tunnel,resulting in fracture *** ground was then uplifted due to the large inflow of the slurry and the excess pore water ***,the lessons learned from this incident were *** presented case study provides a reference for tunnel construction in urban areas with water-rich strata.

关键词： Grouting Ground heave Building damage Field test Numerical simulation