检索结果-南通市图书馆

A molecular dynamics investigation of the deformation mechanism and shape memory effect of epoxy shape memory polymers

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2016年第3期59卷 89-95页

作者： Hua yang Zheng Dao Wang ya fang guo Xing Hua Shi Institute of Engineering Mechanics Beijing Jiaotong University State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences

Following deformation, thermally induced shape memory polymers(SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behaviors of three types of epoxy SMPs with varying curing agent contents were investigated using a molecular dynamics(MD) method. The mechanical properties under uniaxial tension at different temperatures were obtained, and the simulation results compared reasonably with experimental data. In addition, in a thermomechanical cycle, ideal shape memory effects for the three types of SMPs were revealed through the shape frozen and shape recovery responses at low and high temperatures, respectively, indicating that the recovery time is strongly influenced by the ratio of E-51 to 4,4'-Methylenedianiline.

关键词： shape memory polymer molecular dynamics simulation thermomechanics

Molecular Dynamics Simulations of the Orientation Effect on the Initial Plastic Deformation of Magnesium Single Crystals

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2016年第3期29卷 301-312页

作者： Qun Zu ya-fang guo Shuang Xu Xiao-Zhi Tang Yue-Sheng Wang Institute of Engineering Mechanics Beijing Jiaotong University School of Science Wuhan University of Technology

Molecular dynamics simulation is employed to study the tension and compression deformation behaviors of magnesium single crystals with different *** angle between the loading axis and the basal direction ranges from 0° to 90°.The simulation results show that the initial defects usually nucleate at free surfaces,but the initial plastic deformation and the subsequent microstructural evolutions are various due to different loading *** tension simulations exhibit the deformation mechanisms of twinning,slip,crystallographic reorientation and basal/prismatic *** twinning,crystallographic reorientation and basal/prismatic transformation can only appear in the crystal model loaded along or near the a-axis or *** the compression simulations,the basal,prismatic and pyramidal slips are responsible for the initial plasticity,and no twinning is ***,the plastic deformation models affect the yield strengths for the samples with different *** maximum yield stresses for the samples loaded along the c-axis or a-axis are much higher than those loaded in other directions.

关键词： Molecular dynamics simulations Magnesium Plastic deformation Orientation

Recent progress of two-dimensional metal-base catalysts in urea oxidation reaction

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第8期43卷 3607-3633页

作者： Qi-Xiang Huang fang Wang Yong Liu Bi-Ying Zhang fang-ya guo Zhong-Qiu Jia Hao Wang Tian-Xiang yang Hai-Tao Wu Feng-Zhang Ren Ting-Feng Yi School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471000China School of Environmental Engineering and Chemistry Luoyang Institute of Science and TechnologyLuoyang 471023China Henan Province International Joint Laboratory of Materials for Solar Energy Conversion and Lithium Sodium Based Battery Luoyang 471023China School of Chemistry and Life Sciences Suzhou University of Science and TechnologySuzhou 215009China School of Materials Science and Engineering Northeastern UniversityShenyang110819China

Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen more efficiently by low theoretical potential,reduce the average cost of electrochemical hydrogen production,and is a frontier research hotspot for renewable hydrogen ***-dimensional(2D)nanomaterials as electrocatalysts have many favorable potential,such as it can effectively reduce the resistivity of materials and increase the specific surface area with *** paper reviews the application of 2D materials in UOR in alkaline *** a cross-sectional comparison of various material performance data including overpotential,Tafel slope,electrochemical active surface area(ECSA)and it stability test was conducted,which could illustrate the differences between materials composed of different *** addition,the main challenges hindering the progress of research on 2D materials in urea electrocatalysis processes and promising materials in this field in future are summarized and *** is believed that this review will contribute to designing and analyzing highperformance 2D urea electrocatalysts for water splitting.

关键词： Water splitting Urea oxidation reaction Two-dimensional Transition metal compounds Noble/non-noble metals

Atomistic simulations of interactions between screw dislocation and twin boundaries in zirconium

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2018年第6期28卷 1192-1199页

作者： Xiao-zhi TANG Hui-shi ZHANG ya-fang guo Institute of Engineering Mechanics Beijing Jiaotong UniversityBeijing 100044China

Molecular statics was employed to simulate interaction between screw dislocation and twin boundaries（TB） in hexagonal close-packed zirconium. In the moving TB model, the interaction of a moving {10ˉ12} TB with a static 1/311ˉ20{10ˉ10} screw dislocation was investigated. Twinning dislocation（TD） nucleation and movement play an important role in the interaction. The screw dislocation passes through the moving TB and changes to a basal one with a wide core. In the moving dislocation model, a moving 1/31120{1010} dislocation passes through the TB, converting into a basal one containing two partial dislocations and an extremely short stacking fault. If the TB changes to the {1011} one, the moving1/31120{1010} prismatic screw dislocation can be absorbed by the static TB and dissociated into two TDs on the TB. Along with the stress-strain relationship, results reveal the complicated mechanisms of interactions between the dislocation and TBs.

关键词： twin boundary twinning dislocation slip transfer reaction athermal process

Uremic clearance granule combined with Alprostadil in the treatment of chronic renal failure: A systematic review and meta-analysis

在线全文

学校读者我要写书评

暂无评论

TMR Theory and Hypothesis 2019年第3期2卷 195-203页

作者： Jing Gan ya-fang guo Dong-Dong Li Zi-Zheng Zhou Jia-Bao Zhou Jian-Dong Gao Department of Nephrology Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese MedicineTCM institute of kidney disease Shanghai University of Traditional Chinese MedicineKey Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine) Ministry of EducationShanghai Key Laboratory of Traditional Chinese Clinical Medicine (14DZ2273200) Shanghai China Department of TCM Shanghai Pudong Hospital Fudan University Pudong Medical Center Shanghai China

Objective: To evaluate whether the combination of Uremic clearance granule with Alprostadil is superior to Alprostadil alone for CRF. Methods: Relevant RCTs were searched through March 2019. Data were analyzed by Stata 15.0. Results: Nine articles involving 726 patients were enrolled in this study. Meta-analysis showed that the total effective rate [OR = 3.68 (2.44, 5.55), P 0.05) between two groups. No serious adverse reactions were found. Conclusions: The effect of the integrated medicine on CRF was better than Alprostadil alone. Uremic clearance granule is safe and has no obvious adverse reactions.

关键词： Uremic clearance granule Chronic Renal Failure Alprostadil Meta-Analysis

Prevalence of Helicobacter pylori infection in Chinese military personnel:A cross-sectional,multicenter-based study

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2025年第3期31卷 42-49页

作者： Han-Chen Min Chun-yan Zhang fang-Yu Wang Xiao-Hui Yu Shan-Hong Tang Hong-Wu Zhu ya-Gang Zhao Ji-Luo Liu Jian Wang Jing-Han guo Xiao-Mei Zhang Yun-Sheng yang Chinese People’s Liberation Army Medical School Chinese People’s Liberation Army General HospitalBeijing 100853China Department of Gastroenterology and Hepatology The First Medical CenterChinese People’s Liberation Army General HospitalBeijing 100853China Sixth Healthcare Department The Second Medical CenterChinese People’s Liberation Army General HospitalBeijing 100853China Department of Gastroenterology The 940th Hospital of Joint Logistic Support Force of Chinese People’s Liberation ArmyLanzhou 730050Gansu ProvinceChina Department of Gastroenterology General Hospital of Western Theater CommandChengdu 610011Sichuan ProvinceChina Department of Gastroenterology General Hospital of Southern Theater CommandGuangzhou 510010Guangdong ProvinceChina Department of Epidemiology Naval Medical UniversityShanghai 200433China School of Medicine Nankai UniversityTianjin 300071China National Clinical Research Center for Geriatric Diseases Chinese People’s Liberation Army General HospitalBeijing 100853China

BACKGROUND Helicobacter pylori(***)infection is a prevalent disease encountered in military internal medicine and recognized as the main cause of dyspepsia,gastritis,and peptic ulcer,which are common diseases in military *** guidelines in China state all patients with evidence of active infection with *** are offered ***,the prevalence of *** infection and its regional distribution in the military population remain unclear,which hinders effective prevention and treatment *** the prevalence of *** infection in the military population will aid in the development of customized strategies to better manage this infectious *** To investigate the prevalence of *** infection in the Chinese military population in different geographic *** This multicenter,retrospective study included 22421 individuals from five tertiary hospitals located in north,east,southwest,and northwest cities of *** infection was identified using the urea breath test,which had been performed between January 2020 and December *** Of the 22421 military service members,7416(33.1%)were urea breath *** highest prevalence of *** was in the 30-39 years age group for military personnel,with an infection rate of 34.9%.The majority of infected subjects were younger than 40-years-old,accounting for 70.4%of the infected *** individuals serviced in Lanzhou and Chengdu showed a higher infection prevalence than those in Beijing,Nanjing,and Guangzhou,with prevalence rates of 44.3%,37.9%,29.0%,31.1%,and 32.3%,*** *** infection remains a common infectious disease among military personnel in China and has a relatively high prevalence rate in northwest China.

关键词： Helicobacter pylori Prevalence Military personnel Urea breath test Multicenter study

g-C_(3)N_(4)负载双金属Rh@Ru催化氨硼烷析氢反应机理研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第5期42卷 17-21页

作者：郭雅琼武警警官学院成都610213

本文采用密度泛函理论,研究了双金属Rh@Ru在g-C_(3)N_(4)上不同负载位点,确定了稳定的催化剂构型,并详细研究了该催化剂催化氨硼烷析氢的反应机理.通过比较氨硼烷析氢反应三条路径所需活化能,发现路径Ⅲ控制步骤活化能较低,而路径Ⅰ、... 详细信息

本文采用密度泛函理论,研究了双金属Rh@Ru在g-C_(3)N_(4)上不同负载位点,确定了稳定的催化剂构型,并详细研究了该催化剂催化氨硼烷析氢的反应机理.通过比较氨硼烷析氢反应三条路径所需活化能,发现路径Ⅲ控制步骤活化能较低,而路径Ⅰ、Ⅱ所需活化能较高,反应路径Ⅲ更容易进行,Ⅰ为最优析氢路径.从微观角度揭示双贵金属Rh@Ru负载g-C_(3)N_(4)催化氨硼烷析氢的三条机理,希望为氨硼烷析氢催化剂的优化和设计提供理论信息.

关键词：双金属催化剂 g-C_(3)N_(4) NH_(3)BH_(3) 密度泛函理论反应机理

在线全文

学校读者我要写书评

暂无评论

CT仿真胃镜与电子胃镜的对比研究

实用医技杂志 2004年第12A期11卷 2499-2501页

作者：刘剑杨亚芳季国忠南京医科大学第二附属医院江苏南京210011

目的 :通过 CT仿真胃镜 (CT Virtual Gastroscopy,CTVG)与电子胃镜 (Electron Gastroscopy,简称 EG)在胃部病变的诊断价值对比 ,探讨 CT仿真胃镜的临床应用价值。方法 :使用 Hispeed FX/ i扫描机 ,扫描层厚 3.0 mm～5 .0 m m,螺距 1.0 m... 详细信息

目的 :通过 CT仿真胃镜 (CT Virtual Gastroscopy,CTVG)与电子胃镜 (Electron Gastroscopy,简称 EG)在胃部病变的诊断价值对比 ,探讨 CT仿真胃镜的临床应用价值。方法 :使用 Hispeed FX/ i扫描机 ,扫描层厚 3.0 mm～5 .0 m m,螺距 1.0 mm～ 1.5 mm,重建间隔 1.0 mm～ 2 .0 m m,应用 Navigator Smooth功能对 31例病人进行了 CTVG成像。结果 :通过选择不同的观察方位、角度和阈值 ,CTVG能清楚显示靶器官内正常解剖结构的立体影像和病变的部位、大小、形态及其侵犯范围。CTVG对胃部病变形态的显示与 EG显示具有良好的对应性。CTVG显示病变的准确率达 93.5 %。结论 :CTVG作为一种安全、可靠、无痛苦、新的检查方法 ,可以作为 EG的有效补充手段 ,有较好的临床应用价值。

关键词：螺旋CT 仿真胃镜电子胃镜胃

θ-improved limited tolerance relation model of incomplete information system for evaluation of water conservancy project management modernization

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2013年第4期6卷 469-477页

作者： Yu-qin GAO guo-hua fang ya-qin LIU College of Water Conservancy and Hydropower Engineering Hohai University

The modernization of water conservancy project management is a complicated engineering system involving a management system, a management method, management personnel, the exertion of social, economic, and ecological effects, and so on. However, indices for evaluating the modernization of water conservancy project management are usually unobtainable in practical applications. Conducting appropriate extension of the classical rough set theory and then applying it to an incomplete information system are the key to the application of the rough set theory Based on analysis of some extended rough set models in incomplete information systems, a rough set model based on the θ-improved limited tolerance relation is put forward. At the same time, upper approximation and lower approximation are defined under this improved relation. According to the evaluation index system and management practices, the threshold for θ is defined. An example study indicates the practicability and maneuverability of the model.

关键词： Key words: modernization of water conservancy project management O-improved limitedtolerance relation model," upper and lower approximations," threshold