期刊文献+
共找到4,053篇文章
< 1 2 203 >
每页显示 20 50 100
Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury
1
作者 Yan Wang Dai Li +12 位作者 Lan Zhang Zhenyu Yin Zhaoli Han Xintong Ge Meimei Li Jing Zhao Shishuang Zhang Yan Zuo Xiangyang Xiong Han Gao Qiang Liu Fanglian Chen Ping Lei 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第9期2010-2018,共9页
We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repet... We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear.In this study,we first used an HT22 scratch injury model to mimic traumatic brain injury,then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p.We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress.Furthermore,luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α,while an IRE1αfunctional salvage experiment confirmed that miR-124-3p targeted IRE1αand reduced its expression,thereby inhibiting endoplasmic reticulum stress in injured neurons.Finally,we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced.These findings suggest that,after repetitive mild traumatic brain injury,miR-124-3 can be transferred from microglia-derived exosomes to injured neurons,where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress.Therefore,microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury. 展开更多
关键词 apoptosis C/EBP homologous protein endoplasmic reticulum stress EXOSOME inositol-requiring enzyme MICROGLIA miR-124-3p neuron repetitive mild traumatic brain injury X-box binding protein 1
下载PDF
Correlation Study of Neurotransmitter and Immune Levels in Pre-Hospital Emergency Nurses with Post-Traumatic Stress Disorder
2
作者 Yanling Zhou Min Guo +1 位作者 Xiangling Jiang Long Li 《Journal of Behavioral and Brain Science》 2024年第1期12-22,共11页
Objective: To investigate the occurrence of PTSD in pre-hospital emergency nurses and its related factors, and to compare the differences of neurotransmitter and immune-related factors between pre-hospital emergency n... Objective: To investigate the occurrence of PTSD in pre-hospital emergency nurses and its related factors, and to compare the differences of neurotransmitter and immune-related factors between pre-hospital emergency nurses who experienced traumatic events and those who did not develop PTSD and healthy people. How: Post-traumatic Stress Disorder Self-Rating Scale (PCL-C) tests were performed on pre-hospital emergency nurses in PTSD group, non-PTSD group and healthy control group, and the plasma monoamine neurotransmitters and serum cytokines were determined by double-antibody sandwich ABC-ELISA assay using enzyme-linked adsorption kit provided by Shanghai Xitang Biotechnology Co., Ltd. Results: 1) There were statistically significant differences in PCL-C scores between PTSD group, non-PTSD group and healthy group (p α between PTSD group, non-PTSD group and healthy group (p Conclusion: Pre-hospital emergency nurses should have early psychological intervention and guidance to reduce the occurrence of PTSD in emergency and emergency nurses. 展开更多
关键词 pre-Hospital First Aid NURSE Post-Traumatic stress Disorder NEUROIMMUNOLOGY
下载PDF
Coseismic Coulomb stress changes induced by a 2020-2021 M_(W)>7.0 Alaska earthquake sequence in and around the Shumagin gap and its influence on the Alaska-Aleutian subduction interface
3
作者 Lei Yang Jianjun Wang Caijun Xu 《Geodesy and Geodynamics》 EI CSCD 2024年第1期1-12,共12页
Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6... Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench. 展开更多
关键词 The 2020-2021 Alaska earthquake SEQUENCE Coseismic Coulomb stress change Mainshock-aftershock triggering The Alaska-Aleutian subduction interface The Shumagin gap
下载PDF
Exercise-induced modulation of miR-149-5p and MMP9 in LPS-triggered diabetic myoblast ER stress: licorice glycoside E as a potential therapeutic target
4
作者 Yi Du Hong Liu 《Traditional Medicine Research》 2024年第8期23-34,共12页
Background:This study explores the relationship between endoplasmic reticulum(ER)stress and diabetes,particularly focusing on the impact of physical exercise on ER stress mechanisms and identifying potential therapeut... Background:This study explores the relationship between endoplasmic reticulum(ER)stress and diabetes,particularly focusing on the impact of physical exercise on ER stress mechanisms and identifying potential therapeutic drugs and targets for diabetes-related sepsis.The research also incorporates traditional physical therapy perspectives,emphasizing the genomic insights gained from exercise therapy in disease management and prevention.Methods:Gene analysis was conducted on the GSE168796 and GSE94717 datasets to identify ER stress-related genes.Gene interactions and immune cell correlations were mapped using GeneCard and STRING databases.A screening of 2,456 compounds from the TCMSP database was performed to identify potential therapeutic agents,with a focus on their docking potential.Techniques such as luciferase reporter gene assay and RNA interference were used to examine the interactions between microRNA-149-5p and MMP9.Results:The study identified 2,006 differentially expressed genes and 616 miRNAs.Key genes like MMP9,TNF-α,and IL1B were linked to an immunosuppressive state.Licorice glycoside E demonstrated high affinity for MMP9,suggesting its potential effectiveness in treating diabetes.The constructed miRNA network highlighted the regulatory roles of MMP9,IL1B,IFNG,and TNF-α.Experimental evidence confirmed the binding of microRNA-149-5p to MMP9,impacting apoptosis in diabetic cells.Conclusion:The findings highlight the regulatory role of microRNA-149-5p in managing MMP9,a crucial gene in diabetes pathophysiology.Licorice glycoside E emerges as a promising treatment option for diabetes,especially targeting MMP9 affected by ER stress.The study also underscores the significance of physical exercise in modulating ER stress pathways in diabetes management,bridging traditional physical therapy and modern scientific understanding.Our study has limitations.It focuses on the microRNA-149-5p-MMP9 network in sepsis,using cell-based methods without animal or clinical trials.Despite strong in vitro findings,in vivo studies are needed to confirm licorice glycoside E’s therapeutic potential and understand the microRNA-149-5p-MMP9 dynamics in real conditions. 展开更多
关键词 ER stress diabetes physical exercise gene expression microRNA-149-5p MMP9 licorice glycoside E traditional physical therapy genomics insights
下载PDF
非线性M-C强度准则下预应力锚索加固边坡时效稳定性分析M-P法
5
作者 邓东平 杨春会 谢志军 《岩土力学》 EI CAS CSCD 北大核心 2024年第4期1051-1066,共16页
拓展传统极限平衡方法在复杂条件下边坡稳定性分析中的适用性一直是岩土工程界的研究热点。众所周知,边坡岩土体剪切失效一般服从于非线性强度准则,而传统极限平衡方法仅适用于线性强度准则下边坡稳定性分析。此外,预应力锚索作为一种... 拓展传统极限平衡方法在复杂条件下边坡稳定性分析中的适用性一直是岩土工程界的研究热点。众所周知,边坡岩土体剪切失效一般服从于非线性强度准则,而传统极限平衡方法仅适用于线性强度准则下边坡稳定性分析。此外,预应力锚索作为一种主动防护措施,可极大地即时提高边坡稳定性而被广泛应用于中、大型边坡工程加固。然而,在应力松弛、蠕变效应以及腐蚀环境影响下预应力锚索加固边坡稳定性时效特征往往被忽视。由此,基于Morgenstern-Price(M-P)法,嵌入非线性Mohr-Coulomb(M-C)强度准则,并融入应力松弛与蠕变效应下锚索预应力损失模型以及腐蚀环境下锚索性能劣化模型,从而,建立非线性强度准则下预应力锚索加固边坡安全系数时程表达式。进一步,为了解决非线性强度准则下隐式嵌套公式难以求解的问题,归零化条间法向力初始值,并应用迭代循环求解策略,在引入循环终止允许误差判别条件后,可实现边坡稳定性理论真实结果的逼近求解。经过后续算例对比分析,验证了所提方法的可行性和合理性,与此同时,还研究了不同预应力损失速率和不同锈蚀环境下预应力锚索加固边坡稳定性的时效变化规律。 展开更多
关键词 边坡 极限平衡M-P法 非线性M-C强度准则 预应力锚索加固 时效稳定性
下载PDF
书夹型钢-混组合结构在桥梁加宽中的应用研究
6
作者 刘世忠 王方旭 +2 位作者 朱立龙 刘欣益 苏学冰 《桥梁建设》 EI CSCD 北大核心 2024年第4期21-27,共7页
为避免桥梁加宽时下部结构拓宽,减少新旧桥面纵向裂缝及铺装层损伤,提出一种以钢结构立柱及护栏、书夹式钢板、高强度螺栓为主要构件,超高性能混凝土(UHPC)为铺装层的书夹型钢-混组合结构进行桥梁加宽。为评估该组合结构在运营条件下的... 为避免桥梁加宽时下部结构拓宽,减少新旧桥面纵向裂缝及铺装层损伤,提出一种以钢结构立柱及护栏、书夹式钢板、高强度螺栓为主要构件,超高性能混凝土(UHPC)为铺装层的书夹型钢-混组合结构进行桥梁加宽。为评估该组合结构在运营条件下的安全性,以厦门官浔溪大桥加宽工程为背景,通过实桥现场静载试验研究水平荷载作用下书夹型钢-混组合结构的力学性能,并与数值仿真结果进行对比,验证试验结果的可靠性。结果表明:实测结果与数值仿真结果吻合良好;书夹型钢-混组合结构关键部位荷载~位移曲线、荷载~应力曲线呈线性变化,钢结构最大拉应力约为材料屈服强度的75%,整体结构处于弹性工作阶段;螺栓预紧力有效减少了高强度螺栓的直剪作用,降低了剪切疲劳破坏风险;采用书夹型钢-混组合结构进行桥梁加宽可有效避免下部结构拓宽,改善新旧桥面纵向裂缝及铺装层损伤,具有较好的加宽效果。 展开更多
关键词 桥梁加宽 书夹型钢-混组合结构 位移 应力 螺栓预紧力 静载试验 数值仿真
下载PDF
Influence of pre- plastic deformation on thermal residual stress and yield strength of SiC_w/Al composites 被引量:1
7
作者 姜传海 王德尊 姚忠凯 《中国有色金属学会会刊:英文版》 CSCD 2000年第3期393-396,共4页
With a micro mechanical model, the feasibility of modification of thermal residual stress of the composites treated by tensile pre plastic deformation was analyzed. The relationship between pre plastic strain and vari... With a micro mechanical model, the feasibility of modification of thermal residual stress of the composites treated by tensile pre plastic deformation was analyzed. The relationship between pre plastic strain and variation of thermal residual stress was established. By using the method of tensile pre plastic deformation, the thermal residual stress in 20%SiC w/6061Al composites was modified. The results show that, with increasing tensile pre plastic strain, the tensile residual stress in the matrix was decreased to zero gradually, and then it was turned into compressive stress. By comparison, it was found that the changing tendency of the test results is similar to that of theoretical analysis. In addition, due to pre plastic deformation, the dislocation density in the matrix was increased, and the yield strength of the composites was improved. The increasing yield strength is mainly due to the decreasing tensile residual stress and the changing of distribution of dislocation in the matrix. 展开更多
关键词 SIC w/Al pre plastic deformation RESIDUAL stress YIELD strength
下载PDF
The soybean GmPUB21-interacting protein GmDi19-5 responds to drought and salinity stresses via an ABA-dependent pathway
8
作者 Yunhua Yang Rui Ren +8 位作者 Adhimoolam Karthikeyan Jinlong Yin Tongtong Jin Fei Fang Han Cai Mengzhuo Liu Dagang Wang Haijian Zhi Kai Li 《The Crop Journal》 SCIE CSCD 2023年第4期1152-1162,共11页
Drought-induced protein 19(Di19) is a Cys2/His2 zinc-finger protein that functions in plant growth and development and in tolerance to abiotic stresses.Gm PUB21,an E3 ubiquitin ligase,negatively regulates drought and ... Drought-induced protein 19(Di19) is a Cys2/His2 zinc-finger protein that functions in plant growth and development and in tolerance to abiotic stresses.Gm PUB21,an E3 ubiquitin ligase,negatively regulates drought and salinity response in soybean.We identified potential interaction target proteins of Gm PUB21by yeast two-hybrid c DNA library screening,Gm Di19-5 as a candidate.Bimolecular fluorescence complementation and glutathionine-S-transferase pull-down assays confirmed the interaction between Gm Di19-5 and Gm PUB21.Gm Di19-5 was induced by Na Cl,drought,and abscisic acid(ABA) treatments.Gm Di19-5 was expressed in the cytoplasm and nucleus.Gm Di19-5 overexpression conferred hypersensitivity to drought and high salinity,whereas Gm Di19-5 silencing increased drought and salinity tolerance.Transcripts of ABA-and stress response-associated genes including Gm RAB18 and Gm DREB2A were downregulated in Gm Di19-5-overexpressing plants under drought and salinity stresses.ABA decreased the protein level of Gm Di19-5 in vivo,whereas Gm PUB21 increased the decrease of Gm Di19-5 after exogenous ABA application.The accumulation of Gm PUB21 was also inhibited by Gm Di19-5.We conclude that Gm PUB21 and Gm Di19-5 collaborate to regulate drought and salinity tolerance via an ABA-dependent pathway. 展开更多
关键词 SOYBEAN Drought and salinity stresses GmDi19-5 GmPUB21 ABA-dependent pathway
下载PDF
Prediction of flow stress of Ti-15-3 alloy with artificial neural network 被引量:2
9
作者 李萍 单德彬 +2 位作者 薛克敏 吕炎 许沂 《中国有色金属学会会刊:英文版》 CSCD 2001年第1期95-97,共3页
Hot compression experiments were conducted on Ti 15 3 alloy specimens using Gleeble 1500 Thermal Simulator.These tests were focused to obtain the flow stress data under various conditions of strain,strain rate and tem... Hot compression experiments were conducted on Ti 15 3 alloy specimens using Gleeble 1500 Thermal Simulator.These tests were focused to obtain the flow stress data under various conditions of strain,strain rate and temperature. On the basis of these data, the predicting model for the nonlinear relation between flow stress and deformation strain,strain rate and temperature for Ti 15 3 alloy was developed with a back propagation artificial neural network method. Results show that the neural network can reproduce the flow stress in the sampled data and predict the nonsampled data well. Thus the neural network method has been verified to be used to tackle hot deformation problems of Ti 15 3 alloy. [ 展开更多
关键词 artificial NEURAL network Ti-15-3 ALLOY flow stress
下载PDF
Effect of pre-deformation on the stress corrosion cracking susceptibility of aluminum alloy 2519 被引量:15
10
作者 LI Huizhong ZHANG Xinming CHEN Mingan LI Yanfang LIANG Xiaopeng 《Rare Metals》 SCIE EI CAS CSCD 2007年第4期385-390,共6页
The effects of pre-deformation and strain rate on the stress corrosion cracking (SCC) behavior of aluminum alloy 2519 in air and in 3.5% NaCI water solution were investigated by means of slow strain rate tension (S... The effects of pre-deformation and strain rate on the stress corrosion cracking (SCC) behavior of aluminum alloy 2519 in air and in 3.5% NaCI water solution were investigated by means of slow strain rate tension (SSRT), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicate that the alloy is susceptible to SCC in 3.5% NaCI water solution and not in air. At the same pre-deformation, the alloy is more susceptible to SCC at 1.33 × 10^-5 s^-1 than at 6.66 × 10^-5 s^-1. Moreover, it is more susceptible to SCC at free pre-deformation than at 10% pre-deformation at the same strain rate. The number of 0 precipitated along the grain boundaries is reduced and distributed discontinuously, at the same time, the precipitate-free zones (PFZ) become narrow and the susceptibility to stress corrosion cracking is reduced after 10% pre-deformation. 展开更多
关键词 2519 aluminum alloy pre-DEFORMATION slow strain rate tension susceptibility to stress corrosion cracking
下载PDF
Unveiling the planar deformation mechanisms for improved formability in pre-twinned AZ31 Mg alloy sheet at warm temperature
11
作者 Xiaohuan Pan Lifei Wang +8 位作者 Pengbin Lu Hua Zhang Guangsheng Huang Liuwei Zheng Bin Xing Weili Cheng Hongxia Wang Wei Liang Kwang Seon Shin 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第12期4659-4678,共20页
To investigate the role of pre-twins in Mg alloy sheets during warm planar deformation,the stretch forming is conducted at 200℃.Results suggest the formability of the pre-twinned AZ31 Mg alloy sheet is enhanced to 11... To investigate the role of pre-twins in Mg alloy sheets during warm planar deformation,the stretch forming is conducted at 200℃.Results suggest the formability of the pre-twinned AZ31 Mg alloy sheet is enhanced to 11.30 mm.The mechanisms for the improved formability and the deformation behaviors during the planar stretch forming are systematically investigated based on the planar stress states.The Schmid factor for deformation mechanisms are calculated,the results reveal that planar stress states extremely affect the Schmid factor for{10-12}twinning.The detwinning is activated and the prismatic slip is enhanced in the pre-twinned sheet,especially under the planar extension stress state in the outer region.Consequently,the thickness-direction strain is accommodated better.The dynamic recrystallization(DRX)type is continuous DRX(CDRX)regardless of the planar stress state.However,the CDRX degree is greater under the planar extension stress state.Some twin lattices deviate from the perfect{10-12}twinning relation due to the planar compression stress state and the CDRX.The basal texture is weakened when the planar stress state tends to change the texture components. 展开更多
关键词 AZ31 Mg alloy sheet Planar stretch forming Planar stress states Continuous dynamic recrystallization {10-12}tensile twinning
下载PDF
Controlling of weld hot cracks of aluminum alloy sheets by transverse pre-stressing 被引量:1
12
作者 LIU Xuesong,ZHOU Guangtao,WANG Ping,and FANG Hongyuan State Key Laboratory of Advanced Welding Technology Production,Harbin Institute of Technology,Harbin 150001,China 《Rare Metals》 SCIE EI CAS CSCD 2007年第S1期157-161,共5页
A new ideological and theoretical model—a technology to control weld hot cracks by transverse compressive pre-stress in the welding of aluminum alloy was put forward,which was further proved by the subsequent self-de... A new ideological and theoretical model—a technology to control weld hot cracks by transverse compressive pre-stress in the welding of aluminum alloy was put forward,which was further proved by the subsequent self-designed test setup.Experiments are conducted on the fishbone shaped specimen under conventional welding and welding with various pre-stress values.The experimental results turn out that,the initiation rate of the weld hot cracks decreases with increasing values of the compressive pre-stress.When the pre-stress reaches 0.3-0.4 of the yield stress,the cracks even disappear.In mechanical viewpoint,the researches here develop a new way to control weld cracks. 展开更多
关键词 welding with transverse pre-stress weld hot cracks crack initiation rate
下载PDF
Pre-Stressed Rope Reinforced Anti-Sliding Pile 被引量:1
13
作者 XU Jun WANG Chenghua 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第4期887-891,共5页
Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile's retaining performan... Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile's retaining performance into full play, and to treat with landslide fast and economically. The difference between them is that the pre-stressed rope will transfix the whole anti- sliding pile through a prearranged pipe in this structure. The working mechanics, the design method and economic benefit are studied. The results show that the pre-stressed rope reinforced anti-sliding pile can treat with the small and middle landslides or high slopes well and possess the notable advantage of technology and economic. 展开更多
关键词 pre-stressed rope anti-sliding pile composite anti-sliding structure
下载PDF
Design and Preparation of High Elastic Modulus Self-compacting Concrete for Pre-stressed Mass Concrete Structures 被引量:1
14
作者 祝雯 CHEN Yang +4 位作者 LI Fangxian ZHANG Tongsheng HU Jie 韦江雄 YU Qijun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第3期563-573,共11页
Requirements of self-compacting concrete (SCC) applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be s... Requirements of self-compacting concrete (SCC) applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be satisfied by ordinary SCC. In this study, in order to solve the problem, a few principles of SCC design were proposed and the effects of binder amount, fly ash (FA) substitution, aggregate content and gradation on the workability, temperature rise, drying shrinkage and elastic modulus of SCC were investigated. The results and analysis indicate that the primary factor influencing the fluidity was paste content, and the main methods improving the elastic modulusof SCC were a lower sand ratio and an optimized coarse aggregate gradation. Lower adiabatic temperature rise and drying shrinkage were beneficial for decreasing the cement content. Further, based on the optimization of mixture, a C50 grade SCC (with binder amount of only 480 kg/ m3, fly ash substitution of 40%, sand ratio of 51% and proper coarse aggregate gradation (Vs.~0 mm: V10-16 ram: V16.20 mm= 30%: 30%:40%)) with superior workability was successfully prepared. The temperature rise and drying shrinkage of the prepared SCC were significantly reduced, and the elastic modulus reached 37.6 GPa at 28 d. 展开更多
关键词 self-compacting concrete pre-stressed mass structure high elastic modulus adiabatic temperature rise drying shrinkage
下载PDF
Modified Layer-Removal Method for Measurement of Residual Stress in Pre-stretched Aluminium Alloy Plate 被引量:1
15
作者 Liangbao Liu Jianfei Sun +1 位作者 Wuyi Chen Pengfei Sun 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第2期34-40,共7页
Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely d... Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely depend on correctly and efficiently measuring the residual stresses of workpieccs. A modified layer-removal method is proposed to measure residual stress by analysing the characteristics of a traditional, layer-removal method. The coefficients of strain release are then deduced according to the simulation results using the finite element method (FEM). Moreover, the residual stress in a 7075T651 aluminium alloy plate is measured using the proposed method, and the results are then analyzed and compared with the data obtained by the traditional methods. The analysis indicates that the modified layer-removal method is effective and practical for measuring the residual stress distribution in pre-stretched aluminium alloy plates. 展开更多
关键词 pre-stretched aluminium alloy plate residual stress finite dement method(FEM) modified layer-removal
下载PDF
Experimental study on seismic behavior of circular RC columns strengthened with pre-stressed FRP strips 被引量:1
16
作者 Zhou Changdong Lu Xilin +1 位作者 Li Hui Tian Teng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第4期625-642,共18页
Bonding fiber reinforced polymer (FRP) has been commonly used to improve the seismic behavior of circular reinforced concrete (RC) columns in engineering practice. However, FRP jackets have a significant stress hy... Bonding fiber reinforced polymer (FRP) has been commonly used to improve the seismic behavior of circular reinforced concrete (RC) columns in engineering practice. However, FRP jackets have a significant stress hysteresis effect in this strengthening method, and pre-tensioning the FRP can overcome this problem. This paper presents test results of 25 circular RC columns strengthened with pre-stressed FRP strips under low cyclic loading. The pre-stressing of the FRP strips, types of FRP strips and longitudinal reinforcement, axial load ratio, pre-damage degree and surface treatments of the specimens are considered as the primary factors in the tests. According to the failure modes and hysteresis curves of the specimens, these factors are analyzed to investigate their effect on bearing capacity, ductility, hysteretic behavior, energy dissipation capacity and other important seismic behaviors. The results show that the initial lateral confined stress provided by pre-stressed FRP strips can effectively inhibit the emergence and development of diagonal shear cracks, and change the failure modes of specimens from brittle shear failure to bending or bending-shear failure with better ductility. As a result, the bearing capacity, ductility, energy dissipation capacity and deformation capacity of the strengthened specimens are all significantly improved. 展开更多
关键词 experimental study circular reinforced concrete column pre-stress fiber reinforced polymer axial loadratio seismic behavior active confinement
下载PDF
Mechanism of biaxial pre-stress method on welding residual stress and hot cracks controlling
17
作者 刘雪松 周广涛 +2 位作者 王苹 刘昊元 方洪渊 《China Welding》 EI CAS 2009年第1期40-42,共3页
Based on the conventional uniaxial pre-tensile stress method during welding, this study presents a new method of welding with biaxial pre-stress. With the help of numerical simulation, experiments were carried out on ... Based on the conventional uniaxial pre-tensile stress method during welding, this study presents a new method of welding with biaxial pre-stress. With the help of numerical simulation, experiments were carried out on the self-designed device. Except for the control on residual stress and distortion us-welded, the experimental results also show its effect on the prevention of hot cracks, thus this method can make up for the disadvantage of the conventional pre-stress method. Hot cracks disappear when the value of pre-stress surpasses 0. 2 σs(yield limit). Welded thin plates with low-level residual stress, little distortion and no hot cracks are obtained with longitudinal pre-tensile stress level between 0. 6σsand 0. 7σs and precompressive stress between 0. 2 σs and 0. 3 σs in transverse direction. 展开更多
关键词 biaxial pre-stress method welding residual stress and distortion hot cracks simulation
下载PDF
Improvement in electrical properties of high-κ film on Ge substrate by an improved stress relieved pre-oxide method
18
作者 樊继斌 丁晓甫 +3 位作者 刘红侠 谢鹏飞 张袁涛 廖清良 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第2期468-471,共4页
High-κ /Ge gate stack has recently attracted a great deal of attention as a potential candidate to replace planar silicon transistors for sub-22 generation. However, the desorption and volatilization of GeO hamper th... High-κ /Ge gate stack has recently attracted a great deal of attention as a potential candidate to replace planar silicon transistors for sub-22 generation. However, the desorption and volatilization of GeO hamper the development of Ge-based devices. To cope with this challenge, various techniques have been proposed to improve the high-κ /Ge interface. However,these techniques have not been developed perfectly yet to control the interface. Therefore, in this paper, we propose an improved stress relieved pre-oxide(SRPO) method to improve the thermodynamic stability of the high-κ /Ge interface. The x-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM) results indicate that the GeO volatilization of the high-κ /Ge gate stack is efficiently suppressed after 500℃ annealing, and the electrical characteristics are greatly improved. 展开更多
关键词 high-K film GeO volatilization stress relieved pre-oxide ANNEALING
下载PDF
Stress Analysis of New Type Pre-Stressed Anchor Bearing Plate Combining Stamping with Welding Forming and Its Anchorage Zone
19
作者 Daosen Chen Nianchun Deng +1 位作者 Zanzhi Wang Haining Zuo 《World Journal of Engineering and Technology》 2017年第4期33-41,共9页
An anchor bearing plate transfers the anchoring force from anchor plate to the concrete and the pre-stress is formed in the concrete structure. Currently, the main type of anchor bearing plate is cast iron. It is brit... An anchor bearing plate transfers the anchoring force from anchor plate to the concrete and the pre-stress is formed in the concrete structure. Currently, the main type of anchor bearing plate is cast iron. It is brittle during transportation and tension process. This paper presents a new type of anchor bearing plate combined stamping with welding forming. The structure of the new type anchor bearing plate is introduced. The stress states of the anchor bearing plate and anchorage zone under work are studied. Various specifications of anchor bearing plate are studied by ANSYS finite element analysis software following the AASHTO specification. The analysis results are compared with the results of the same type of OVM round-shaped anchor plate. The study results show that the new pre-stressed anchor plates combined stamping with welding forming are feasible and more sturdy which can meet the engineering demand. 展开更多
关键词 pre-stressed Concrete Structure Finite Element Analysis ANCHOR BEARING Plate stress of ANCHORAGE Zone
下载PDF
Correlation of maternal - placental circulation ultrasound parameters with placental hypoxia and oxidative stress in patients with preeclampsia
20
作者 Min Zhao 《Journal of Hainan Medical University》 2017年第20期69-72,共4页
Objective: To study the correlation of maternal - placental circulation ultrasound parameters with placental hypoxia and oxidative stress in patients with preeclampsia. Methods: Patients with preeclampsia who gave bir... Objective: To study the correlation of maternal - placental circulation ultrasound parameters with placental hypoxia and oxidative stress in patients with preeclampsia. Methods: Patients with preeclampsia who gave birth in Shandong jiaotong hospital between March 2015 and February 2017 were select as the PE group of the study, and the healthy pregnant women who gave birth in the hospital during the same period were selected as the control group of the study. Color Doppler ultrasonography was done in the 23-26 weeks of pregnancy to determine the uterine spiral artery PI, RI and S/D levels;after delivery, the placenta was collected to determine the expression of hypoxia-induced apoptosis indexes, cell invasion molecules and oxidative stress molecules. Results: Uterine spiral artery PI, RI and S/D levels of PE group were significantly higher than those of control group;TXNIP, NLRP3, ASC, Caspase-1, Nrf-2, HO-1 and NQO-1 mRNA expression in placenta tissue of PE group were significantly higher than those of control group and positively correlated with uterine spiral artery PI, RI and S/D levels while CatL, CatB, uPA and LAMA4 mRNA expression were significantly lower than those of control group and negatively correlated with uterine spiral artery PI, RI and S/D levels. Conclusion: The increase of maternal - placental circulation blood resistance in patients with preeclampsia will result in the placental hypoxia, and aggravate the apoptosis and oxidative stress. 展开更多
关键词 preECLAMPSIA MATERNAL - PLACENTAL CIRCULATION Apoptosis INVASION Oxidative stress
下载PDF
上一页 1 2 203 下一页 到第
使用帮助 返回顶部