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GB11947—89变形尺寸规定的管见
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作者 邓雪霞 《建材标准化与质量管理》 1997年第2期29-29,共1页
关键词 陶瓷砖 釉面砖 标准 变形尺寸 计算公式
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牛皮卡纸尺寸变形性的试验研究
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作者 张秋玲 赵嘉薇 《黑龙江造纸》 1999年第3期22-23,共2页
对牛皮卡纸尺寸变形性的试验研究结果表明:卡纸的横向变形性大于纵向变形性,而且。
关键词 牛皮卡纸 尺寸变形 水份 紧度
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热压键合工艺参数对微流控芯片微通道尺寸变形的影响
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作者 梁帅 舒海涛 +1 位作者 张思华 万卓 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2022年第2期95-101,108,共8页
为减小环烯烃共聚物(COC)芯片热压键合过程中微通道的变形量,采用单因素实验研究了热键合参数对COC芯片微通道变形的影响规律,为键合参数的设置提供一定的理论指导。研究结果表明,键合参数对芯片微通道的变形有较大影响,键合温度的影响... 为减小环烯烃共聚物(COC)芯片热压键合过程中微通道的变形量,采用单因素实验研究了热键合参数对COC芯片微通道变形的影响规律,为键合参数的设置提供一定的理论指导。研究结果表明,键合参数对芯片微通道的变形有较大影响,键合温度的影响最大,对应的变形量最大极差为20.76,键合压力次之,键合时间的影响最小,对应的最小极差为5.04μm,且与连续相相比,键合参数对COC芯片微通道离散相尺寸变形影响更为显著;在热键合过程中,温度和压力过高会使芯片微通道产生永久变形甚至毁坏芯片微结构,为减小变形,可适当地降低键合温度和压力,延长键合时间来弥补键合不完全的问题。 展开更多
关键词 热压键合 环烯烃共聚物 微流通控芯片 微通道 尺寸变形
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热处理尺寸变形超差问题的分析
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作者 韩淑兰 张书丽 于秀梅 《哈尔滨轴承》 2007年第3期21-22,共2页
针对特轻系列产品在热处理过程中尺寸变形超差问题进行了分析,并采取了一系列解决措施,效果良好。
关键词 轴承 热处理 尺寸变形 椭圆度 内应力
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多因素杂糅扰动下硬质聚氨酯泡沫尺寸变化评估模型研究 被引量:1
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作者 范才全 王永帅 +3 位作者 孙晓凯 刘铁伟 张向平 李青溪 《家电科技》 2022年第S01期52-55,共4页
泡沫尺寸变形率是影响门体变形问题的重要因素。研究了以模温、保温、时间为例的多维度工艺过程参数杂糅变化时对泡沫尺寸变形率影响规律的评估模型。该模型具有定性评价各种体系形成的聚氨酯泡沫尺寸变形率的合格性和变化趋势的能力,... 泡沫尺寸变形率是影响门体变形问题的重要因素。研究了以模温、保温、时间为例的多维度工艺过程参数杂糅变化时对泡沫尺寸变形率影响规律的评估模型。该模型具有定性评价各种体系形成的聚氨酯泡沫尺寸变形率的合格性和变化趋势的能力,并对定性评估的能力进行了可靠性验证。 展开更多
关键词 聚氨酯泡沫 尺寸变形 过程工艺参数 评估模型 可靠性
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大尺寸薄片齿轮精密加工工艺创新
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作者 张东生 冯晓维 《国防制造技术》 2021年第2期70-71,48,共3页
大尺寸薄片齿轮属于薄板类零件,其径厚比大,尺寸、形位公差要求高,加工过程中,装夹、切削变形大,常规的磨削加工方法要保证较高精度的端面跳动和两端面的平行度很困难。本文通过加工工艺方法创新,改进装夹方式,改变切削过程中工件的受... 大尺寸薄片齿轮属于薄板类零件,其径厚比大,尺寸、形位公差要求高,加工过程中,装夹、切削变形大,常规的磨削加工方法要保证较高精度的端面跳动和两端面的平行度很困难。本文通过加工工艺方法创新,改进装夹方式,改变切削过程中工件的受力方向,优化切削参数等实现了大尺寸薄片齿轮的精密加工,提高了产品质量。 展开更多
关键词 薄片齿轮大尺寸高精度加工变形 工艺方法创新
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基于SLS的快速树脂模具技术研究
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作者 尚晓峰 杨申波 《工具技术》 2012年第11期36-37,共2页
将环氧树脂和固化剂按不同比例混合后摇匀,分别涂抹在SLS烧结件上,测试SLS烧结件的固化时间和固化强度;并将涂抹后的SLS烧结件放在恒温干燥箱,研究不同温度下对烧结件的影响。试验结果表明,固化剂的用量和固化环境温度对烧结件有一定影响。
关键词 树脂 固化时间 尺寸变形 固化强度
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基于SLS的快速树脂模具技术研究 被引量:1
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作者 杨申波 尚晓峰 《西安工程大学学报》 CAS 2012年第6期771-773,共3页
将环氧树脂和固化剂按不同比例配合后摇匀,分别涂抹在SLS烧结件上,测试SLS烧结件的固化时间和固化强度;并对涂抹后的SLS烧结件放在恒温干燥箱,研究不同温度下对烧结件的影响.结果表明,固化剂的用量和固化环境温度对烧结件有一定影响.
关键词 树脂 固化时间 尺寸变形 固化强度
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Effect of surface nanocrystallization and PPEC time on complex nanocrystalline hard layer fabricated by plasma electrolysis 被引量:6
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作者 M.ALIOFKHAZRAEI SH.AHANGAR ANI A.SABOUR ROUHAGHDAM 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第3期425-431,共7页
Size distribution of nano-carbides produced by duplex treatments of surface nanocrystallization(by surface severe plastic deformation) and plasma electrolytic carburizing on CP-Ti was investigated.Skewness and kurtosi... Size distribution of nano-carbides produced by duplex treatments of surface nanocrystallization(by surface severe plastic deformation) and plasma electrolytic carburizing on CP-Ti was investigated.Skewness and kurtosis of Gussian shape distribution curves were studied and the effect of time was determined.The usage of longer time is more suitable for achieving less size of complex nano-carbides.Surface roughness of treated samples was measured.It is observed that there is an optimum level for time on surface roughness increasing(difference between two measured data). 展开更多
关键词 surface nanocrystallization hard layer ROUGHNESS CP-Ti
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Effect of indentation size and grain/sub-grain size on microhardness of high purity tungsten 被引量:2
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作者 刘光玉 倪颂 宋旼 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第10期3240-3246,共7页
Hardness of materials depends significantly on the indentation size and grain/sub-grain size via microindentation and nanoindentation tests of high-purity tungsten with different structures.The grain boundary effect a... Hardness of materials depends significantly on the indentation size and grain/sub-grain size via microindentation and nanoindentation tests of high-purity tungsten with different structures.The grain boundary effect and indentation size effect were explored.The indentation hardness was fitted using the Nix-Gao model by considering the scaling factor.The results show that the scaling factor is barely correlated with the grain/sub-grain size.The interaction between the plastically deformed zone(PDZ) boundary and the grain/sub-grain boundary is believed to be the reason that leads to an increase of the measured hardness at the specific depths.Results also indicate that the area of the PDZ is barely correlated with the grain/sub-grain size,and the indentation hardness starts to stabilize once the PDZ expands to the dimension of an individual grain/sub-grain. 展开更多
关键词 high purity tungsten indentation hardness indentation size effect grain boundary plastic deformation zone
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Investigation on Zener-Hollomon parameter in the warm-hot deformation behavior of 20CrMnTi 被引量:9
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作者 YANG Hui LI Zhen-hong ZHANG Zhi-liang 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第8期1453-1460,共8页
The warm-hot deformation behavior of 20CrMnTi steel was studied with hot compression tests at temperature range of 1123-1273 K and strain rate of 0.1-20 s^-1. The activation energy for warm-hot deformation is 426.064 ... The warm-hot deformation behavior of 20CrMnTi steel was studied with hot compression tests at temperature range of 1123-1273 K and strain rate of 0.1-20 s^-1. The activation energy for warm-hot deformation is 426.064 KJ/mol. The influences of Zener-Hollomon parameter, strain and grain size imposing on the flow stress were analyzed in the temperature range of warm-hot forging. Creep theory and mathematical theory of statistics were used to obtain mathematical models of flow stress. The research and results provide scientific basis for controlling microstructure of forging process through Zener-Hollomon parameter. 展开更多
关键词 Zener-Hollomon parameter Warm-hot deformation 20CrMnTi Grain size
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Deformation behavior of materials in micro-forming with consideration of intragranular heterogeneities 被引量:2
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作者 Zhen-wu MA Guo-quan TONG Feng CHEN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第3期616-626,共11页
To describe the relationship between the whole material deformation behavior and each grain deformation behavior inmicro-forming,experimental and numerical modelling methods were employed.Tensile test results reveal t... To describe the relationship between the whole material deformation behavior and each grain deformation behavior inmicro-forming,experimental and numerical modelling methods were employed.Tensile test results reveal that contrary to the valueof flow stress,the scatter of flow stress decreases with the increase of thickness-to-grain diameter(T/d)ratio.Microhardnessevaluation results show that each grain owns unique deformation behavior and randomly distributes in each specimen.The specimenwith less number of grains would be more likely to form an easy deformation zone and produce the concentration of plasticdeformation.Based on the experiment results,a size-dependent model considering the effects of grain size,geometry size,and thedeformation behavior of each grain was developed.And the effectiveness and practicability of the size-dependent model wereverified by experimental results. 展开更多
关键词 MICRO-FORMING deformation behavior size effect model intragranular heterogeneity
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Experimental study on complete stress-deformation curves of larger-size concrete specimens subjected to uniaxial tension 被引量:1
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作者 CHEN Ping LIANG Zheng-ping +1 位作者 HUANG Shu-qin CHEN Yu-quan 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第8期1296-1304,共9页
In order to provide parameters for numerical analyses of the huge Three-Gorge concrete dam (2309 m long by 175 m height), complete tensile stress-deformation curves for large-size plain concrete specimens were measure... In order to provide parameters for numerical analyses of the huge Three-Gorge concrete dam (2309 m long by 175 m height), complete tensile stress-deformation curves for large-size plain concrete specimens were measured and studied by per-forming uniaxial tensile tests on large-size unnotched specimens (250 mm×250 mm×1400 mm). The specimens were prepared with the three-graded-aggregate materials provided by the client of the Three-Gorge project. To prevent a failure occurring near the ends of the unnotched specimens, both the ends of each specimen (450 mm in length) were cast using a higher-strength concrete than the middle part (i.e., active part). Tensile tests were completed on a specially-designed tensile testing machine, which can be easily re-assembled to accommodate different-size specimens. To make the specimens fail stably, a cyclic loading scheme was adopted after the peak strength was reached. Four of five tests in this study were successful, and four complete tensile stress-deformation curves were obtained. It was found that the post-peak curve of the large-size specimens used in this study is more gradual than those for the small-size specimens reported in the literature. 展开更多
关键词 CONCRETE Uniaxial tensile tests Tensile stress DEFORMATION Large-size specimens
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FE-based coupling simulation of Ti60 alloy in isothermal upsetting process 被引量:2
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作者 罗皎 李淼泉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第5期849-856,共8页
A constitutive equation was proposed to describe the effect of grain size on the deformation behavior.And a coupling simulation of deformation with heat transfer and microstructure was carried out in isothermal upsett... A constitutive equation was proposed to describe the effect of grain size on the deformation behavior.And a coupling simulation of deformation with heat transfer and microstructure was carried out in isothermal upsetting process of Ti60 alloy.The effects of processing parameters on the equivalent strain,the equivalent stress,the temperature rise and the grain size distribution in isothermal upsetting process of Ti60 alloy were analyzed.It is concluded that the uniformity of equivalent strain and equivalent stress increases with the increase of deformation temperature.However,the temperature rise and the grain size decreases with the increase of deformation temperature.The non-uniformity of equivalent strain,equivalent stress,temperature field and grain size increases with the increase of height reduction.And the calculated grain size using simulation is in good agreement with the experimental one. 展开更多
关键词 titanium alloy coupling simulation constitutive equation grain size
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Effect of height of rock specimen on strain localization, precursor to failure and entire deformational characteristics 被引量:1
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作者 王学滨 《Journal of Coal Science & Engineering(China)》 2006年第2期16-20,共5页
Patterns of shear band, precursors to shear failure occurring in strain-softening stage, axial, lateral and volumetric strains as well as Poisson's ratio of plane strain rock specimens in compression for different he... Patterns of shear band, precursors to shear failure occurring in strain-softening stage, axial, lateral and volumetric strains as well as Poisson's ratio of plane strain rock specimens in compression for different heights were investigated by use of Fast Lagrangian Analysis of Continua(FLAC). A material imperfection closer to the lower-left corner of the specimen was prescribed. For finer mesh, the imperfection was modeled by four null elements, while it was modeled by a null element for coarser mesh. FISH functions were written to calculate the entire deformational characteristics of the specimen. In elastic stage, the adopted constitutive relation was linear elastic; in strain-softening stage, a composite Mohr-Coulomb criterion with tension cut-off and a post-peak linear constitutive relation were adopted. Height of rock specimen does not influence shear band's pattern (including the thickness and inclination angle of shear band). The slopes of the post-peak stress-axial strain curve, stress-lateral strain curve, lateral strain-axial strain curve, Poisson's ratio-axial strain curve and volumetric strain-axial strain curve depend on the height. Hence, the slopes of these curves cannot be considered as material properties. Nonlinear deformation prior to the peak stress is a kind of precursors to shear failure, which is less apparent for shorter specimen. For the same axial strain, lower lateral expansion is reached for shorter specimen, leading to lower Poisson's ratio and higher volumetric strain. The maximum volumetric strain of longer specimen is less than that of shorter specimen. The conclusions drawn from numerical results using finer mesh qualitatively agree with those using coarser mesh. 展开更多
关键词 shear band size effect PRECURSOR axial strain lateral strain volumetric strain
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Grain size effect on cyclic deformation behavior and springback prediction of Ni-based superalloy foil 被引量:5
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作者 Wei-lin HE Bao MENG +1 位作者 Bing-yi SONG Min WAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第4期1188-1204,共17页
In order to clarify the influence of grain size on cyclic deformation response of superalloy sheets and springback behavior,cyclic loading-unloading and shearing tests were performed on the superalloy foils with 0.2 m... In order to clarify the influence of grain size on cyclic deformation response of superalloy sheets and springback behavior,cyclic loading-unloading and shearing tests were performed on the superalloy foils with 0.2 mm in thickness and diverse grain sizes.The results show that,the decline ratio of elastic modulus is weakened with increasing grain size,and the Bauschinger effect becomes evident with decreasing grain size.Meanwhile,U-bending test results determine that the springback is diminished with increasing grain size.The Chaboche,Anisotropic Nonlinear Kinematic(ANK)and Yoshida-Uemori(Y-U)models were utilized to fit the shear stress-strain curves of specimens.It is found that Y-U model is sufficient of predicting the springback.However,the prediction accuracy is degraded with increasing grain size. 展开更多
关键词 grain size effect cyclic deformation superalloy foil hardening model springback prediction
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New constitutive equation utilizing grain size for modeling of hot deformation behavior of AA1070 aluminum 被引量:9
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作者 H.R.REZAEI ASHTIANI A.A.SHAYANPOOR 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第2期345-357,共13页
A new phenomenological and empirically-based constitutive model was proposed to modify the term in the original Johnson−Cook constitutive model.The new model can be used to describe and predict the flow stress of AA10... A new phenomenological and empirically-based constitutive model was proposed to modify the term in the original Johnson−Cook constitutive model.The new model can be used to describe and predict the flow stress of AA1070 aluminum with different initial grain sizes in the hot working process.This developed model considers thermal softening,strain-rate hardening,strain hardening,initial grain size,and interactions with each other and can correctly model the behavior of AA1070 at elevated temperature with different strains,strain rates,and initial grain sizes.The hot flow behavior of AA1070 was investigated through compression tests over wide ranges of temperature from 623 to 773 K,strain rate from 0.005 to 0.5 s−1 and initial grain size from 50 to 450μm.Results show that the initial grain size has a significant effect on the flow behavior of AA1070.Then,correlation coefficient(R),average absolute relative error(AARE),and relative error were examined for comparative predictability of the model.Results show that flow stresses for different initial grain sizes calculated by the new proposed model perfectly correlate with experimental ones,with a mean relative error of 1.19%,which confirms that the new modified Johnson−Cook relation can give a precise estimation of the hot flow stress of AA1070 aluminum by considering the initial grain size. 展开更多
关键词 constitutive equation modified Johnson−Cook model initial grain size flow stress hot deformation AA1070 aluminum
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Effects of initial bubble size on geometric and motion characteristics of bubble released in water 被引量:4
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作者 KANG Can ZHANG Wei +1 位作者 ZOU Zi-wen PANG Chun-bo 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第12期3021-3032,共12页
To seek and describe the influence of bubble size on geometric and motion characteristics of the bubble,six nozzles with different outlet diameters were selected to inject air into water and to produce different bubbl... To seek and describe the influence of bubble size on geometric and motion characteristics of the bubble,six nozzles with different outlet diameters were selected to inject air into water and to produce different bubble sizes.High-speed photography in conjunction with an in-house bubble image processing code was used.During the evolution of the bubble,bubble shape,traveling trajectory and the variation of bubble velocity were obtained.Bubble sizes acquired varied from0.25to8.69mm.The results show that after the bubble is separated from the nozzle,bubble shape sequentially experiences ellipsoidal shape,hat shape,mushroom shape and eventually the stable ellipsoidal shape.As the bubble size increases,the oscillation of the bubble surface is intensified.At the stabilization stage of bubble motion,bubble trajectories conform approximately to the sinusoidal function.Meanwhile,with the increase in bubble size,the bubble trajectory tends to be straightened and the influence of the horizontal bubble velocity component on the bubble trajectory attenuates.The present results explain the phenomena related to relatively large bubble size,which extends the existing relationship between the bubble terminal velocity and the equivalent bubble diameter. 展开更多
关键词 bubble size nozzle diameter bubble deformation aspect ratio bubble terminal velocity
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美国铝业公司研发出Al-Mg系免热处理铸造铝合金 被引量:1
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《铸造工程》 2022年第3期42-42,共1页
近年,随着特斯拉而兴起的大型一体化压铸技术已成为行业最热门的发展趋势之一,而一体化压铸工艺的推广应用,需要设备、模具、工艺、材料等与之相配套。由于一体化压铸件的投影面积大,热处理极易引起零部件的尺寸变形及表面缺陷,对于大... 近年,随着特斯拉而兴起的大型一体化压铸技术已成为行业最热门的发展趋势之一,而一体化压铸工艺的推广应用,需要设备、模具、工艺、材料等与之相配套。由于一体化压铸件的投影面积大,热处理极易引起零部件的尺寸变形及表面缺陷,对于大型一体化零部件来说,需承担巨大的成本风险。所以,一体化压铸件倾向于使用免热处理的铝合金材料。 展开更多
关键词 铸造铝合金 压铸件 压铸工艺 压铸技术 美国铝业公司 铝合金材料 投影面积 尺寸变形
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In situ Nanomechanical Research on Large-Scale Plastic Deformation of Individual Ultrathin Multi-walled Carbon Nanotube
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作者 Guo-xin Chen Jun-feng Cui +4 位作者 Huan-ming Lu Jin-hong Yu Yan Liu He Li Nan Jiang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第4期485-490,I0003,共7页
Carbon nanotubes are a promising candidate for the application of flexible electronics due to the ultrahigh intrinsic conductivity and excellent mechanical flexibility. In the present work, the morphology of the ultra... Carbon nanotubes are a promising candidate for the application of flexible electronics due to the ultrahigh intrinsic conductivity and excellent mechanical flexibility. In the present work, the morphology of the ultrathin (diameter<20 nm) multi-walled carbon nanotubes (MWCNTs) under an axial compression was investigated by using in-situ transmission electron microscopy. Moreover, the overall dynamic deformation processes and the force-displacement (F-D) curves of the MWCNTs were also examined. Interestingly, the MWCNTs almost restored their original morphology after 15 loading-unloading cycles. The deformation and recovery process indicate that the MWCNTs are flexible and exhibit excellent durability against compression. The Young’s modulus of the MWCNTs is estimated with the value of ∽0.655 TPa derived from the F-D curves fitting. Our results suggest that the ultrathin carbon nanotube structures may have great application potentials in flexible devices. 展开更多
关键词 Carbon nanotubes In-situ transmission electron microscopy Large-scale deformation Young's modulus F-D curve
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