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Action of trichostatin A on Alzheimer’s disease-like pathological changes in SH-SY5Y neuroblastoma cells 预览
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作者 Li-Hua Li Wen-Na Peng +2 位作者 Yu Deng1 Jing-Jing Li Xiang-Rong Tian 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第2期293-301,共9页
The histone deacetylase inhibitor, trichostatin A, is used to treat Alzheimer’s disease and can improve learning and memory but its underlying mechanism of action is unknown. To determine whether the therapeutic effe... The histone deacetylase inhibitor, trichostatin A, is used to treat Alzheimer’s disease and can improve learning and memory but its underlying mechanism of action is unknown. To determine whether the therapeutic effect of trichostatin A on Alzheimer’s disease is associated with the nuclear factor erythroid 2-related factor 2(Nrf2) and Kelch-like epichlorohydrin-related protein-1(Keap1) signaling pathway, amyloid β-peptide 25–35(Aβ25–35) was used to induce Alzheimer’s disease-like pathological changes in SH-SY5 Y neuroblastoma cells. Cells were then treated with trichostatin A. The effects of trichostatin A on the expression of Keap1 and Nrf2 were detected by real-time quantitative polymerase chain reaction, western blot assays and immunofluorescence. Total antioxidant capacity and autophagy activity were evaluated by total antioxidant capacity assay kit and light chain 3-I/II levels, respectively. We found that trichostatin A increased cell viability and Nrf2 expression, and decreased Keap1 expression in SH-SY5 Y cells. Furthermore, trichostatin A increased the expression of Nrf2-related target genes, such as superoxide dismutase, NAD(P)H quinone dehydrogenase 1 and glutathione S-transferase, thereby increasing the total antioxidant capacity of SH-SY5 Y cells and inhibiting amyloid β-peptide-induced autophagy. Knockdown of Keap1 in SH-SY5 Y cells further increased trichostatin A-induced Nrf2 expression. These results indicate that the therapeutic effect of trichostatin A on Alzheimer’s disease is associated with the Keap1-Nrf2 pathway. The mechanism for this action may be that trichostatin A increases cell viability and the antioxidant capacity of SH-SY5 Y cells by alleviating Keap1-mediated inhibition Nrf2 signaling, thereby alleviating amyloid β-peptide-induced cell damage. 展开更多
关键词 Alzheimer's disease amyloid-β peptide autophagy KEAP1 signal neurocytotoxicity oxidative stress damage SH-SY5Y cells total antioxidant capacity transcription factor Nrf2 TSA
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聚集体自噬在运动性骨骼肌损伤中的特征 预览
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作者 高扬 梁孝天 +2 位作者 王博 李俊平 王瑞元 《中国组织工程研究》 CAS 北大核心 2020年第5期720-725,共6页
背景:一次大负荷离心运动会诱导骨骼肌损伤、内质网应激、错误折叠蛋白增多,聚集体自噬作为蛋白质质量控制的途径之一,在损伤修复过程中应当发挥一定的作用。目的:探讨一次大负荷离心运动诱导骨骼肌损伤恢复过程中聚集体自噬的激活程度... 背景:一次大负荷离心运动会诱导骨骼肌损伤、内质网应激、错误折叠蛋白增多,聚集体自噬作为蛋白质质量控制的途径之一,在损伤修复过程中应当发挥一定的作用。目的:探讨一次大负荷离心运动诱导骨骼肌损伤恢复过程中聚集体自噬的激活程度,分析聚集体自噬在运动诱导骨骼肌损伤中的作用,以完善运动诱导骨骼肌损伤的蛋白降解途径。方法:将64只成年雄性SD大鼠(购自北京维通利华实验技术有限公司)随机分为安静对照组(n=8)和运动组(n=56),运动组又按运动后时相分为0,3,6,12,24,48,72h组,每组8只。运动组大鼠进行一次跑台下坡跑运动(-16°,16 m/min,90 min),分别在运动后的相应时刻取比目鱼肌,使用透视电子显微镜观察损伤发生程度,采用Western Blot方法检测比目鱼肌难溶蛋白聚集体自噬相关蛋白组蛋白去乙酰化酶6和微管相关蛋白1轻链3Ⅱ/Ⅰ的蛋白表达。实验获得北京体育大学运动科学实验伦理委员会批准(2016030A)。结果与结论:(1)透射电镜显示一次大负荷离心运动后,大鼠比目鱼肌出现一过性的肌节紊乱、变宽,Z线呈水波状、断裂直至消失,线粒体肿胀、分布不均、结构不清,其中运动后12h损伤最为严重,于运动后72h完全恢复;(2)Western Blot检测显示,一次性离心运动后即刻组蛋白去乙酰化酶6显著增高,运动后6 h达到峰值,之后逐渐降低,运动后72 h恢复到对照组水平;一次性离心运动后3 h的微管相关蛋白1轻链3Ⅱ/Ⅰ显著升高,运动后12h达到峰值,之后显著降低,运动后72 h恢复到对照组水平;(3)结果表明,一次大负荷离心运动后一过性发生聚集体自噬,在清除错误折叠蛋白、维持细胞环境稳定和骨骼肌损伤恢复中发挥着重要作用。 展开更多
关键词 聚集体自噬 微管相关蛋白1轻链3 组蛋白去乙酰化酶6 运动 骨骼肌 损伤 难溶性蛋白 组织工程
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Bone marrow-derived mesenchymal stem cell transplantation attenuates overexpression of inflammatory mediators in rat brain after cardiopulmonary resuscitation 预览
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作者 Qing-Ming Lin Xia-Hong Tang +2 位作者 Shi-Rong Lin Ben-Dun Chen Feng Chen 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第2期324-331,共8页
Emerging evidence suggests that bone marrow-derived mesenchymal stem cell transplantation improves neurological function after cardiac arrest and cardiopulmonary resuscitation;however, the precise mechanisms remain un... Emerging evidence suggests that bone marrow-derived mesenchymal stem cell transplantation improves neurological function after cardiac arrest and cardiopulmonary resuscitation;however, the precise mechanisms remain unclear. This study aimed to investigate the effect of bone marrow-derived mesenchymal stem cell treatment on expression profiles of multiple cytokines in the brain after cardiac arrest and cardiopulmonary resuscitation. Cardiac arrest was induced in rats by asphyxia and cardiopulmonary resuscitation was initiated 6 minutes after cardiac arrest. One hour after successful cardiopulmonary resuscitation, rats were injected with either phosphate-buffered saline(control) or 1 × 10~6 bone marrow-derived mesenchymal stem cells via the tail vein. Serum S100 B levels were measured by enzyme-linked immunosorbent assay and neurological deficit scores were evaluated to assess brain damage at 3 days after cardiopulmonary resuscitation. Serum S100 B levels were remarkably decreased and neurological deficit scores were obviously improved in the mesenchymal stem cell group compared with the phosphate-buffered saline group. Brains were isolated from the rats and expression levels of 90 proteins were determined using a RayBio Rat Antibody Array, to investigate the cytokine profiles. Brain levels of the inflammatory mediators tumor necrosis factor-α, interferon-γ, macrophage inflammatory protein-1α, macrophage inflammatory protein-2, macrophage inflammatory protein-3α, macrophage-derived chemokine, and matrix metalloproteinase-2 were decreased ≥ 1.5-fold, while levels of the anti-inflammatory factor interleukin-10 were increased ≥ 1.5-fold in the mesenchymal stem cell group compared with the control group. Donor mesenchymal stem cells were detected by immunofluorescence to determine their distribution in the damaged brain, and were primarily observed in the cerebral cortex. These results indicate that bone marrow-derived mesenchymal stem cell transplantation attenuates brain damage induced by cardiac arrest and 展开更多
关键词 antibody array ASPHYXIA brain damage cardiac arrest CARDIOPULMONARY RESUSCITATION global cerebral ischemia inflammatory mediator mesenchymal stem cell NEUROLOGICAL DEFICIT score S100B
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Therapeutic potential of natural compounds from Chinese medicine in acute and subacute phases of ischemic stroke 预览
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作者 Bei Zhang Kathryn ESaatman Lei Chen 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第3期416-424,共9页
Stroke is one of the leading causes of death and disability in adults worldwide,resulting in huge social and financial burdens.Extracts from herbs,especially those used in Chinese medicine,have emerged as new pharmace... Stroke is one of the leading causes of death and disability in adults worldwide,resulting in huge social and financial burdens.Extracts from herbs,especially those used in Chinese medicine,have emerged as new pharmaceuticals for stroke treatment.Here we review the evidence from preclinical studies investigating neuroprotective properties of Chinese medicinal compounds through their application in acute and subacute phases of ischemic stroke,and highlight potential mechanisms underlying their therapeutic effects.It is noteworthy that many herbal compounds have been shown to target multiple mechanisms and in combinations may exert synergistic effects on signaling pathways,thereby attenuating multiple aspects of ischemic pathology.We conclude the paper with a general discussion of the prospects for novel natural compound-based regimens against stroke. 展开更多
关键词 cell death HERBAL compound immune response ISCHEMIC stroke therapy NEUROPLASTICITY NEUROPROTECTION oxidative damage traditional Chinese medicine
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Environmental Effects on Electronic Devices in Mexico 预览
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作者 Francisco Sánchez Pérez Armando Ortiz Prado 《材料科学与应用期刊(英文)》 2019年第3期243-252,共10页
This paper shows the results of the assessment of impairment suffered by elements of electronic equipment by environmental effects in different climatic zones of Mexico. For this study, evaluated devices were evaluate... This paper shows the results of the assessment of impairment suffered by elements of electronic equipment by environmental effects in different climatic zones of Mexico. For this study, evaluated devices were evaluated that are mostly exposed under different climatic conditions of operation, to determine the degree of damage suffered which leads to malfunction, reduced service life and loss of information in some cases. The main contribution is to identify the causes of the deterioration to delay the effect of atmospheric corrosion deterioration in electronic components. The Mexican Republic has a wide range of climates and subclimates over its territory, sampling was performed for each one of the most representative regions, by their nature tend to be more conducive to the release of corrosive effect on the computer and electronic devices. For the determination of existing impairment in electronic equipment, a methodology is proposed for the evaluation of samples taken from each region, determining the degree of corrosion that exists in these devices. It should be noted that according to the literature, the main pollutants that lead to the deterioration caused by corrosive environmental phenomena are SO2, NOx, CO, CO2, coupled with the presence of ozone and chloride, characteristic of the coastal region, combined with the percent relative humidity (% HR), and temperature cycles as reported by environmental monitoring systems in Mexico. With the study of atmospheric corrosivity in electronic devices has been determined: 1) Design and operation of chamber to accelerated atmospheric corrosion testing. 2) Identification of electronic components with increased susceptibility to corrosive phenomena under typical environmental different regions of Mexico. 3) Correlation of damage suffered in electronic equipment under typical operating conditions and accelerated tests. 4) Determining the degree of atmospheric corrosion on electronic equipment. 5) Construction of atmospheric corrosivity map for Mexico in electronic devi 展开更多
关键词 ATMOSPHERIC CORROSION DAMAGE Electronic Devices DEGREE of ATMOSPHERIC CORROSION CORROSIVITY MAP
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Research status and progress of tunnel frost damage
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作者 Yanbin Luo Jianxun Chen 《交通运输工程学报(英文版)》 CSCD 2019年第3期297-309,共13页
The problems of frost damage in cold region tunnels have been systematically analyzed and studied by local and foreign scholars. A series of important achievements has been proposed. In this paper, the research result... The problems of frost damage in cold region tunnels have been systematically analyzed and studied by local and foreign scholars. A series of important achievements has been proposed. In this paper, the research results on mechanism of frost damage, analysis of temperature field, classification of frost damage levels, and frost prevention technologies are summarized. The principles and limitations of the three major theories of frost damage mechanism are elaborated, and the importance of structural damage research on shotcrete in cold region tunnels is emphasized. Two major defects of current research on temperature field are concluded. The present situation of research on frost damage classification of cold region tunnels is discussed. The directions of further studies for tunnel temperature field and frost damage classification are proposed. The prevention technologies for tunnel frost damage in foreign countries, and the advantages and disadvantages of the four major prevention technologies in China and their applicable conditions, are concluded and analyzed. Meanwhile, the importance of frost damage classification is highlighted. Therefore, the local and foreign research results for cold region tunnels are systematically concluded, the defects of the researches are comprehensively analyzed, and the directions of further study are proposed. They are significant to solve the problems of tunnel frost damage in the future. 展开更多
关键词 COLD region TUNNEL FROST DAMAGE mechanism Temperature field TUNNEL FROST DAMAGE classification Prevention MEASURE
MCPIP1 mediates inflammatory responses induced by lipopolysaccharide and lipoteichoic acid in bovine mammary epithelial cells
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作者 Shaopei Qi Lixue Wang +3 位作者 Xiao Chang Yanfen Zhang Yong Zhang Ming-Qing Gao 《生物化学与生物物理学报:英文版》 SCIE CAS CSCD 2019年第2期150-158,共9页
Monocyte chemoattractant protein-induced protein 1(MCPIP1)is a kind of zinc finger RNA binding protein,which exerts immune responses in a variety of cell types.However,the role of MCPIP1 in bovine mammary epithelial c... Monocyte chemoattractant protein-induced protein 1(MCPIP1)is a kind of zinc finger RNA binding protein,which exerts immune responses in a variety of cell types.However,the role of MCPIP1 in bovine mammary epithelial cells during mastitis has not been studied.In this study,we explored the functions of MCPIP1 in the inflammatory process induced by virulence factors of pathogens in bovine mammary alveolar cell-T(MAC-T)cell line.Our results showed that MCPIP1 was significantly highly expressed both in the mammary tissue of dairy cows with mastitis and in inflammatory MAC-T cells induced by lipopolysaccharide(LPS)or lipoteichoic acid(LTA).Furthermore,we found that overexpression of MCPIP1 in MAC-T cells abated the LPS-induced increase at the gene expression levels of inflammatory mediators tumor necrosis factor-α-α,interleukin(IL)-1β,IL-6 and IL-8,enhanced the LPS-and LTA-induced inhibition of epithelial proliferation and promoted the LPS-and LTA-induced oxidative and DNA damage.These findings indicated that MCPIP1 has an enormous potential in regulating the inflammatory response of bovine mammary epithelial cells during infection and may provide an effective therapeutic target for bovine mastitis to reduce the damage caused by inflammatory reactions. 展开更多
关键词 MCPIP1 BOVINE MAMMARY EPITHELIAL cell INFLAMMATORY response DNA DAMAGE oxidative DAMAGE
Mechanical Characterization and Measurement of the Damage of <i>Pericopsis elata</i>(Assamela) 预览
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作者 Ulrich Gael Azeufack Bienvenu Kenmeugne +3 位作者 Emmanuel Foadieng Martial Fouotsa Pierre Kisito Talla M. Fogue 《世界工程和技术(英文)》 2019年第2期256-269,共14页
The prediction of the mechanical properties of wood and the evolution of its damage has been essential for its application in many fields such as bridges and houses construction, racks of trucks and so on. In more val... The prediction of the mechanical properties of wood and the evolution of its damage has been essential for its application in many fields such as bridges and houses construction, racks of trucks and so on. In more valorization of biomaterials following the example material wood arouses for a few years a?private interest on behalf of the populations. The experimental characterization?makes it possible to consider the mechanical properties local of Pericopsis elata (Assamela) according to various parameters (the wood turpentine, the orientation of wood fibers, water the content, the type of test …). From the?results, we evaluate the mechanical characteristics of Pericopsis elata (Assamela)?according to the three directions of Orthotropy. Then from the tests of load-discharge we measured the evolution of the damage using the variation of the Young modulus, which enabled us to note the reduction in the modulus of elasticity because of the damage following the three directions. Finally we noted a progressive and irreversible degradation of mechanical properties induced by the development of the microscopic cracks within material. 展开更多
关键词 Wood Mechanical Properties Modulus of ELASTICITY DAMAGE ORTHOTROPIC Cycles Loading UNLOADING
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Damage Tolerance Assessment of a Brake Unit Bracket for High-Speed Railway Welded Bogie Frames 预览
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作者 Bing Yang Hao Duan +1 位作者 Shengchuan Wu Guozheng Kang 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第4期184-194,共11页
The brake unit bracket of a bogie frame is an important load-carrying component, particularly under emergency start/stop conditions. Conventional infinite/safe life approaches provide an over-conservative recommendati... The brake unit bracket of a bogie frame is an important load-carrying component, particularly under emergency start/stop conditions. Conventional infinite/safe life approaches provide an over-conservative recommendation for the allowable strength and lifetime, which hinders the lightweight design of modern railway vehicles. In this study, to ensure the reliability and durability of a brake unit bracket, an attempt was made to integrate the nominal stress method and an advanced damage tolerance method. First, a complex bogie frame was modelled using solid elements instead of plate and beam elements. A hot spot stress region on the bracket was found under an eight-stage load spectrum obtained from the Wuhan–Guangzhou high-speed railway line. Based on the probability of foreign damage, a semi-elliptical surface crack was then assumed for residual life assessment. The results obtained by the cumulative damage and damage tolerance methods show that the brake unit bracket can operate for over 30 years. Moreover, even if a 2-mm depth crack exists, the brake unit bracket can be safely operated for more than 2.27 years, with the hope that the crack can be detected in subsequent maintenance procedures. Finally, an appropriate safety margin was suggested which provides a basis for the life prediction and durability assessment of brake unit brackets of high-speed railways. 展开更多
关键词 Welded BOGIE frame Fatigue DAMAGE accumulation DAMAGE tolerance design Residual life ASSESSMENT High-speed railway vehicle
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船舶撞击荷载作用下高桩墩的破坏分析 预览
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作者 陈宇 吕杨 +1 位作者 齐广政 孙熙平 《水利水运工程学报》 CSCD 北大核心 2019年第2期25-32,共8页
提出了以动量守恒定律为基础,试算输入不同简化撞击力时间荷载曲线,计算结构的动力响应与现场检测结果一致为准则,基于有限元模型分析船撞结构损伤破坏的数值分析方法。以中泉石化船撞高桩系缆墩事故为背景,运用通用有限元显示动力分析... 提出了以动量守恒定律为基础,试算输入不同简化撞击力时间荷载曲线,计算结构的动力响应与现场检测结果一致为准则,基于有限元模型分析船撞结构损伤破坏的数值分析方法。以中泉石化船撞高桩系缆墩事故为背景,运用通用有限元显示动力分析软件LS-DYNA,建立了高桩系缆墩的三维有限元模型,采用所提出的方法计算分析了受撞系缆墩的破坏过程。数值分析结果表明,当撞击时间为13.75s时,系缆墩残余位移与现场检测结果一致,系缆墩在船舶撞击作用下墩台发生剪切破坏的现象与事故现场相符;同时数值模拟结果表明系缆墩灌注桩混凝土在嵌岩端上部发生不同程度破坏,钢套筒进入屈服阶段;对系缆墩结构整体进行损伤等级评估,属于中等破坏。 展开更多
关键词 高桩系缆墩 撞击 损伤 破坏模式
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Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of <i>Entandrophragma cylindricum</i>(Sapelli) and <i>Chlorophora exelcia</i>(Iroko) 预览
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作者 Thierry Fothe Ulrich Gael Azeufack +2 位作者 Bienvenu Kenmeugne Pierre Kisito Talla Médard Fogue 《世界工程和技术(英文)》 2019年第4期549-558,共10页
This work aims at characterizing the evolution of the damage of two tropical hardwoods. Two species from Cameroon, the Entandrophragma Cylindricum and the Chlorora Exelcia were used for the purpose. Repeated compressi... This work aims at characterizing the evolution of the damage of two tropical hardwoods. Two species from Cameroon, the Entandrophragma Cylindricum and the Chlorora Exelcia were used for the purpose. Repeated compressive loading has been made on specimens strictly selected along with longitudinal and radial directions of each species. Each cycle was made of one phase of monotonic loading and a phase of elastic release. From data obtained, we determined the variation of Young modulus and plastic deformation during each cycle of loading, and we had deduced the damage of the material. Results show that the damage appears only after a certain threshold of the plastic deformation;that damage then grows exponentially to reach a threshold after which the failure of the material occurs. As well, we noticed that the growth of damage is accompanied by the progressive decrease of the Young modulus;this confirms the deteriorating effect of the damage on the mechanical properties. Elsewhere, the damage failure threshold is less than the theoretical value, and differs from one direction to another. Finally, we noticed that the damage failure threshold of sapelli is greater than that of iroko that allows concluding that iroko gets damaged and fails more rapidly than sapelli. 展开更多
关键词 Damage Wood Measurement Cyclic Test MODULUS of ELASTICITY
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Intensity Distribution of the Mojiang MS 5. 9 Earthquake in Yunnan in 2018 预览
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作者 LU Yongkun ZHOU Yang +2 位作者 DAI Boyang YANG Jianqiang YAN Hang 《中国地震研究:英文版》 CSCD 2019年第1期74-85,共12页
The distribution of the intensity of the Mojiang MS5. 9 earthquake in Yunnan Province is expounded, and the damage characteristics of buildings and the damage ratio and seismic damage index of various building structu... The distribution of the intensity of the Mojiang MS5. 9 earthquake in Yunnan Province is expounded, and the damage characteristics of buildings and the damage ratio and seismic damage index of various building structures in each intensity area are compared with those of The Chinese Seismic Intensity Scale. The main basis and method of seismic intensity assessment are discussed in this paper. It is concluded that:① The seismic intensity should be based on the earthquake damage of the housing structure, which takes up a high ratio in the seismic intensity assessment. It is recommended that seismic intensity is estimated by calculating the average seismic damage index.② The highest intensity of the Mojiang MS5. 9 earthquake is Ⅷ degrees, with the long axis trending in the north-west direction. The area above Ⅶ degrees is 5,180km^2 .③ The intensity distribution of the Mojiang MS5. 9 earthquake meets the national standard and the distribution law of seismic intensity in Yunnan. 展开更多
关键词 Mojiang MS5. 9 EARTHQUAKE SEISMIC INTENSITY DAMAGE RATIO SEISMIC DAMAGE index
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卫星结构弹性碰撞减损的研究与仿真
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作者 赵华 余快 范宁 《机械强度》 CAS CSCD 北大核心 2019年第1期33-38,共6页
在飞行段卫星需要承受复杂的动力学载荷条件,是引起航天器结构受损或设备故障的主要阶段。多颗卫星地面力学环境试验表明,对于质量大或质心高的一类设备,时常由于很大的加速度响应而引起结构受损,对工程研制带来较大影响。提出一种不同... 在飞行段卫星需要承受复杂的动力学载荷条件,是引起航天器结构受损或设备故障的主要阶段。多颗卫星地面力学环境试验表明,对于质量大或质心高的一类设备,时常由于很大的加速度响应而引起结构受损,对工程研制带来较大影响。提出一种不同以往的工程解决方法,即采用间隙弹性碰撞改变刚度和限幅的非线性方法,可以达到较好的减损效果。通过构建动力学模型和仿真分析表明,该方法能够减小连接部位蜂窝板的变形和载荷,在工程上提供了一种新的解决途径。 展开更多
关键词 卫星结构 加速度响应 损伤 碰撞限幅 仿真 减损
Damage Initiation and Propagation in Composites Subjected to Low Velocity Impact:Experimental Results,3D Dynamic Damage Model,and FEM Simulations 预览
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作者 JIA Wenbin WEN Weidong FANG Lei 《南京航空航天大学学报:英文版》 EI CSCD 2019年第3期488-499,共12页
A three-dimensional dynamic damage model that fits both small and large damage sizes is developed to predict impact damage initiation and propagation for each lamina of T300-carbon/epoxy laminations.First,13 specimens... A three-dimensional dynamic damage model that fits both small and large damage sizes is developed to predict impact damage initiation and propagation for each lamina of T300-carbon/epoxy laminations.First,13 specimens of the same lamination sequence are subjected to three different impact energies(10 J,15 J,and 20 J).After the impact,the laminates are inspected by the naked eye to observe the damage in the outer layers,and subsequently X-rayed to detect the inner damage.Next,the stress analysis of laminates subjected to impact loading is presented,based on the Hertz contact law and virtual displacement principle.Based on the analysis results,a three-dimensional dynamic damage model is proposed,including the Hou failure criteria and Camanho stiffness degradation model,to predict the impact damage shape and area.The numerical predictions of the damage shape and area show a relatively reasonable agreement with the experiments.Finally,the impact damage initiation and propagation for each lamina are investigated using this damage model,and the results improve the understanding of the impact process. 展开更多
关键词 COMPOSITES IMPACT three-dimensional DYNAMIC DAMAGE model IMPACT DAMAGE INITIATION and PROPAGATION
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混凝土宏观损伤本构研究进展 预览
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作者 申波 刘盼盼 +2 位作者 马克俭 陈映 谢宗言 《贵州大学学报:自然科学版》 2019年第2期7-12,共6页
损伤本构关系的研究是混凝土力学性能研究的重要内容,从损伤本构关系确立的过程入手,给出了损伤变量的选取、损伤变量的演化规律及损伤模型的确立三方面内容。主要针对弹性、弹塑性本构模型分类进行阐述,对比各损伤本构模型的不同和优劣... 损伤本构关系的研究是混凝土力学性能研究的重要内容,从损伤本构关系确立的过程入手,给出了损伤变量的选取、损伤变量的演化规律及损伤模型的确立三方面内容。主要针对弹性、弹塑性本构模型分类进行阐述,对比各损伤本构模型的不同和优劣,总结了混凝土宏观损伤本构的研究进展,为混凝土宏观损伤本构关系研究提供思路。 展开更多
关键词 混凝土 损伤 本构关系 损伤演化
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枪管基体组织对枪管寿命的影响 预览
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作者 胡春东 何星 +2 位作者 陆恒昌 董瀚 李峻松 《兵工学报》 EI CAS CSCD 北大核心 2019年第4期728-736,共9页
为了探明枪管基体组织对枪管损伤速率影响的机理,对比研究了两种不同基体组织枪管在射击过程中的损伤表现。采用光学显微镜、扫描电子显微镜对枪管基体组织进行表征,通过碳复型、相分析对枪管基体组织进行分析。结果表明,低硬度枪管损... 为了探明枪管基体组织对枪管损伤速率影响的机理,对比研究了两种不同基体组织枪管在射击过程中的损伤表现。采用光学显微镜、扫描电子显微镜对枪管基体组织进行表征,通过碳复型、相分析对枪管基体组织进行分析。结果表明,低硬度枪管损伤速率大于高硬度枪管,导致前者寿命较低。出现这一结果的原因是:一方面低硬度枪管内表面发生了较大的塑性变形,导致内径扩大速率增加,寿命缩短;另一方面高硬度基体碳化物分布较为细小、弥散,抑制裂纹形核扩展能力大于低硬度基体。 展开更多
关键词 枪管 损伤 枪管寿命 枪管钢
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重载铁路75 kg/m钢轨的换轨周期研究 预览
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作者 田常海 《铁道标准设计》 北大核心 2019年第8期1-5,共5页
通过持续调研大秦重载铁路75 kg/m钢轨使用和重伤情况,进行钢轨重伤类型和每千米重伤量统计分析,获得钢轨主要重伤类型、不同地段一定累计通过总重对应的每千米钢轨重伤量;针对不同长度地段钢轨重伤量数据,提出钢轨重伤加权统计方法,利... 通过持续调研大秦重载铁路75 kg/m钢轨使用和重伤情况,进行钢轨重伤类型和每千米重伤量统计分析,获得钢轨主要重伤类型、不同地段一定累计通过总重对应的每千米钢轨重伤量;针对不同长度地段钢轨重伤量数据,提出钢轨重伤加权统计方法,利用回归分析方法和不同地段钢轨重伤量数据,获得大秦重载铁路75 kg/m钢轨整亿吨通过总重下加权重伤量数据;利用大秦重载铁路各种钢轨维修费用数据进行经济分析,获得钢轨经济下道周期;通过2006年和2016年钢轨重伤统计数据对比分析,结合我国运输特点及经济分析结果,提出累计通过总重与每千米钢轨重伤量相结合的大修换轨周期,并估算了延长换轨周期的经济效益。 展开更多
关键词 重载铁路 75 KG/M钢轨 伤损 经济分析 加权统计 换轨周期
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基于红外热像技术的风力机微裂纹叶片研究
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作者 陈长征 王琳琳 +3 位作者 周勃 张亚楠 马天畅 俞方艾 《太阳能学报》 EI CAS CSCD 北大核心 2019年第2期417-421,共5页
通过对有边缘微裂纹的兆瓦级风力机叶片试件进行拉伸断裂试验,采用红外热像仪全程监测试件表面温度,研究复合材料叶片微裂纹损伤区内温度场变化,分析试件拉伸断裂过程中的损伤演变情况。结果表明:1)塑性功转变成热的热耗散因子为80%;2)... 通过对有边缘微裂纹的兆瓦级风力机叶片试件进行拉伸断裂试验,采用红外热像仪全程监测试件表面温度,研究复合材料叶片微裂纹损伤区内温度场变化,分析试件拉伸断裂过程中的损伤演变情况。结果表明:1)塑性功转变成热的热耗散因子为80%;2)微裂纹裂尖温度变化趋势为先线性下降后升高;3)试验中发现试件温度场断裂前无明显变化;4)试件断裂损伤形式有纤维断裂、分层、界面脱粘。 展开更多
关键词 红外热像 温度场 热耗散 损伤
养性殿西暖阁仙楼佛堂唐卡的病害及病害机理研究 预览
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作者 方小济 张蕊 +1 位作者 王猷 周倩 《遗产与保护研究》 2019年第4期5-12,共8页
故宫养性殿西暖阁仙楼佛堂保存着22轴唐卡,这些唐卡均为乾隆时期的作品,因长时间挂供于佛堂之内,出现了各种病害。文章通过现场踏勘与科学分析,对这些唐卡进行病害调查、理清病害的种类及病害机理,以期能为这些唐卡的保护修复提供科学... 故宫养性殿西暖阁仙楼佛堂保存着22轴唐卡,这些唐卡均为乾隆时期的作品,因长时间挂供于佛堂之内,出现了各种病害。文章通过现场踏勘与科学分析,对这些唐卡进行病害调查、理清病害的种类及病害机理,以期能为这些唐卡的保护修复提供科学依据。 展开更多
关键词 故宫 养性殿 乾隆 唐卡 病害
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金属材料声发射信号传播的声阻抗特性研究 预览
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作者 毛汉颖 刘婷 +1 位作者 范健文 毛汉领 《振动与冲击》 EI CSCD 北大核心 2019年第13期197-201,214共6页
金属材料声发射信号的传播特性是研究声发射技术的重要基础,声阻抗是表征金属材料动态特性的重要物理量,用声阻抗研究声发射信号传播特性,将有助于声发射信号在损伤检测中的应用。在综述金属材料声阻抗实测估计研究的基础上,提出了估计... 金属材料声发射信号的传播特性是研究声发射技术的重要基础,声阻抗是表征金属材料动态特性的重要物理量,用声阻抗研究声发射信号传播特性,将有助于声发射信号在损伤检测中的应用。在综述金属材料声阻抗实测估计研究的基础上,提出了估计金属材料声发射信号声阻抗的方法,探讨了金属材料在经受荷载并卸载后以断铅声发射信号估计其声阻抗的方法。数值模拟和实验数据分析表明,通过断铅声发射可以估计材料经受荷载的声阻抗变化,金属材料声发射信号声阻抗估计值可以较好的表征声发射信号的传播特性,甚至还可能对材料经受荷载情况进行声阻抗成像,可能成为材料内部损伤检测的新方向。 展开更多
关键词 金属材料 声发射 声阻抗 传播特性 损伤
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