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| 1 | Structures and antifouling properties of low surface energy non-toxic antifouling coatings modified by nano-SiO_2 powder显示文摘Antifouling coatings are used to improve the speed and energy efficiency of ships by preventing or- ganisms, such as barnacles and weed, building up on the underwater hull and helping the ships movement through the water. Typically, marine coatings are tributyltin self-polishing copolymer paints containing toxic molecules called biocides. They have been the most successful in combating bio- fouling on ships, but their widespread use has caused severe pollution in the marine ecosystem. The low surface energy marine coating is an entirely non-toxic alternative, which reduces the adhesion strength of marine organisms, facilitating their hydrodynamic removal at high speeds. In this paper, the novel low surface energy non-toxic marine antifouling coatings were prepared with modified acrylic resin, nano-SiO2, and other pigments. The effects of nano-SiO2 on the surface structure and elastic modulus of coating films have been studied, and the seawater test has been carried out in the Dalian Bay. The results showed that micro-nano layered structures on the coating films and the lowest surface energy and elastic modulus could be obtained when an appropriate mass ratio of resin, nano-SiO2, and other pigments in coatings approached. The seawater exposure test has shown that the lower the sur- face energy and elastic modulus of coatings are, the less the marine biofouling adheres on the coating films. | CHEN MeiLing, QU YuanYuan, YANG Li & GAO Hong Laboratory of Marine Coatings, Dalian Jiaotong University, Dalian 116028, China | 2008 | Science China Chemistry2008,51,9: | 17 |
| 2 | Unified solutions for stresses and displacements around circular tunnels using the Unified Strength Theory显示文摘The unified solutions are presented for stresses and displacements around a circular tunnel subjected to a hydrostatic stress field.The rock mass is assumed to be elastic-brittle-plastic and governed by the Unified Strength Theory.The displacements are obtained accounting for three different definitions for elastic strains and different Young's modulus in the plastic zone.The unified solutions obtained in this paper are especially versatile in reflecting the intermediate principal stress effect to different extents for different materials.The conventional solutions,based on the Mohr-Coulomb failure criterion and the Generalized Twin Shear Stress yield criterion,are special cases of the present unified solutions.The new unified solutions can compare with those computed by the latest generalized Hoek-Brown failure criterion.The results obtained demonstrate the importance of the intermediate principal stress influence for the stresses and displacements analysis.The effects of different definitions for elastic strains and different Young's modulus in the plastic zone on the displacements are significant. | ZHANG ChangGuang1,WANG JiangFeng2 & ZHAO JunHai3 1 Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China 2 North China Institute of Water Conservancy and Hydroelectric Power,Zhengzhou 450011,China 3 School of Civil Engineering,Chang’an University,Xi’an 710061,China | 2010 | Science China(Technological Sciences)2010,53,6: | 8 |
| 3 | Predicting superhard materials via a machine learning informed evolutionary structure search显示文摘The computational prediction of superhard materials would enable the in silico design of compounds that could be used in a wide variety of technological applications.Herein,good agreement was found between experimental Vickers hardnesses,Hv,of a wide range of materials and those calculated by three macroscopic hardness models that employ the shear and/or bulk moduli obtained from:(i)first principles via AFLOW-AEL(AFLOW Automatic Elastic Library),and(ii)a machine learning(ML)model trained on materials within the AFLOW repository.Because H^(ML)_(v) values can be quickly estimated,they can be used in conjunction with an evolutionary search to predict stable,superhard materials.This methodology is implemented in the XTALOPT evolutionary algorithm.Each crystal is minimized to the nearest local minimum,and its Vickers hardness is computed via a linear relationship with the shear modulus discovered by Teter.Both the energy/enthalpy and H^(ML)_(v),Teter are employed to determine a structure’s fitness.This implementation is applied towards the carbon system,and 43 new superhard phases are found.A topological analysis reveals that phases estimated to be slightly harder than diamond contain a substantial fraction of diamond and/or lonsdaleite. | Patrick Avery Xiaoyu Wang Corey Oses Eric Gossett Davide M.Proserpio Cormac Toher Stefano Curtarolo Eva Zurek | 2019 | npj Computational Materials2019,,1: | 7 |
| 4 | 低弹性模量Ti-27Nb-8Zr医用钛合金组织与力学性能(英文)显示文摘利用光学显微镜、扫描电镜和X射线衍射仪研究Ti-27Nb-8Zr(质量分数,%)医用钛合金固溶后在不同时效温度下组织的变化规律,重点讨论不同显微组织对合金弹性模量和强度的影响。结果表明,固溶处理后,合金组织由β+α'两相构成,具有相对低的弹性模量和强度;时效后,组织中包含β、α、ω三相,弹性模量和强度显著升高,随着时效温度的升高,组织长大,弹性模量和强度降低。 | 赵杰 段洪涛 李海涛 | 2010 | 稀有金属材料与工程2010,39,10: | 6 |
| 5 | A new method of estimating the equivalent elastic modulus of RCCD显示文摘Based on the composite material mechanic theory, the analysis method for the equivalent elastic moduli which are parallel and vertical to the construction interface of RCCD is studied in this paper. The differences between the equivalent elastic moduli which are vertical to the construction interface of RCCD gotten from different methods are discussed in detail. The variation range of the equivalent elastic modulus which is vertical to the construction interface of RCCD is studied based on the principle of minimum complementary energy and the principle of minimum potential energy. The effect of the related influential factors on the equivalent elastic modulus is analyzed. The estimation formula of the equivalent modulus which is vertical to the construction interface of RCCD is proposed. The feasibility of the approach proposed in this paper is analyzed through an example. | GU ChongShi1,2?, WU Yuan1, SU HuaiZhi1,2 & TANG LiHui1 1 College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China 2 National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Nanjing 210098, China | 2007 | Science China(Technological Sciences)2007,50,z1: | 6 |
| 6 | Analysis of working behavior of Jinping-I Arch Dam during initial impoundment显示文摘To study the stress, deformation, and seepage pressure during the initial impoundment of the Jinping-I Arch Dam, monitoring analysis and numerical calculation were used in a dam behavior analysis that focused on the working behavior of the dam during the late period of the initial impoundment up to the end of November 2014. The numerical calculation was performed based on feedback analysis of the deformation and stress of the arch dam through inversion of the elastic moduli(E) of the dam body and foundation, using a three-dimensional finite element model for the linear elastic material of the arch dam. The main monitoring indices presented insignificant changes in the late period of the initial impoundment, and the results of feedback analysis were consistent with monitoring results. Analysis results also show that the deformations of the dam body and dam foundation were within the design range; the dam stress distributions were normal, with values lower than the design control criteria; and the seepage flows through the dam body and dam foundation were lower than the design drainage capacity of the deep-well pump house, demonstrating that the Jinping-I Arch Dam was in good working condition, and the initial impoundment had been successfully completed. The results of the working behavior analysis of the Jinping-I hydropower project during the initial impoundment can provide references for safe operation of similar projects. | Shi-yong Wu Wei Cao Jiang Zheng | 2016 | Water Science and Engineering2016,9,3: | 5 |
| 7 | Effect of thermo-mechanical treatment on mechanical and elastic properties of Ti–36Nb–5Zr alloy显示文摘The evolutions of phase constitutions and mechanical properties of a β-phase Ti–36Nb–5Zr(wt%) alloy during thermo-mechanical treatment were investigated. The alloy consisted of dual(β t α″) phase and exhibited a double yielding phenomenon in solution treated state. After cold rolling and subsequent annealing at 698 K for 20 min, an excellent combination of high strength(833 MPa) and low modulus(46 GPa) was obtained. The high strength can be attributed to high density of dislocations, nanosized α phase and grain refinement. On the other hand, the low Young's modulus originates from the suppression of chemical stabilization of β phase during annealing, which guarantees the low β-phase stability. Furthermore, the single-crystal elastic constants of the annealed Ti–36Nb–5Zr alloy were extracted from polycrystalline alloy using an in-situ synchrotron X-ray technique. The results indicated that the low shear modulus C44 contributes to the low Young's modulus for the Ti–36Nb–5Zr alloy, suggesting that reducing C44 through thermo-mechanical treatment might be an efficient approach to realize low Young's modulus in β-phase Ti alloys. The results achieved in this study could be helpful to elucidate the origin of low modulus and sheds light on developing novel biomedical Ti alloys with both low modulus and high strength. | Qingkun Meng Qing Liu Shun Guo Yongqi Zhu Xinqing Zhao | 2015 | Progress in Natural Science:Materials International2015,25,3: | 5 |
| 8 | Elastic modulus of claystone evaluated by nano-/micro-indentation tests and meso-compression tests显示文摘Toarcian claystone such as that of the Callovo-Oxfordian is a qualified multiphase material. The claystone samples tested in this study are composed of four main mineral phases: silicates(clay minerals, quartz,feldspars, micas)(z86%), sulphides(pyrite)(z3%), carbonates(calcite, dolomite)(z10%) and organic kerogen(z1%). Three sets of measurements of the modulus of deformability were compared as determined in(i) nanoindentation tests with a constant indentation depth of 2 mm,(ii) micro-indentation tests with a constant indentation depth of 20 mm, and(iii) meso-compression tests with a constant displacement of 200 mm. These three experimental methods have already been validated in earlier studies. The main objective of this study is to demonstrate the influence of the scaling effect on the modulus of deformability of the material. Different frequency distributions of the modulus of deformability were obtained at the different sample scales:(i) in nano-indentation tests, the distribution was spread between 15 GPa and 90 GPa and contained one peak at34 GPa and another at 51 GPa;(ii) in the micro-indentation tests, the distribution was spread between 25 GPa and 60 GPa and displayed peaks at 26 GPa and 37 GPa; and(iii) in the meso-compression tests, a narrow frequency distribution was obtained, ranging from 25 GPa to 50 GPa and with a maximum at around 35 GPa. | Christophe Auvray Noémie Lafrance Danièle Bartier | 2017 | Journal of Rock Mechanics and Geotechnical Engineering2017,9,1: | 4 |
| 9 | RELATIONSHIP OF LENNARD-JONES POTENTIAL ANDMORSE POTENTIAL WITH W_x(r) POTENTIAL显示文摘RELATIONSHIPOFLENNARD-JONESPOTENTIALANDMORSEPOTENTIALWITHW_x(r)POTENTIALXie,Youqing(DepartementofMaterialsScienceandEngineein... | Xie , Youqing(Departement of Materials Science and Engineeing ,Central South University of Technology ,Changsha 410083) | 1994 | 中国有色金属学会会刊:英文版1994,4,3: | 4 |
| 10 | A UNIFIED ENERGY APPROACH TO A CLASS OF MICROMECHANICS MODELS FOR MICROCRACKED SOLIDS显示文摘Micromechanics models have been developed for the determination ofthe elastic moduli of microcracked solids based on different approaches andinterpretations,including the dilute or non-interacting solution,the Mori-Tanakamethod,the self-consistent method,and the generalized self-consistent method.It isshown in the present study that all these micromechanics models can be unified withinan energy-equivalence framework,and that they differ only in the way in which themicrocrack opening and sliding displacements are evaluated.Relevance to thedifferential methods and the verification of these models are discussed. | HUANG, Y HWANG, KC | 1995 | Acta Mechanica Solida Sinica1995,8,2: | 4 |
| 11 | Use of a Digital Image Correlation Technique for Measuring the Material Properties of Beetle Wing显示文摘Beetle wings are very specialized flight organs consisting of the veins and membranes.Therefore it is necessary from abionic view to investigate the material properties of a beetle wing experimentally.In the present study,we have used a DigitalImage Correlation (DIC) technique to measure the elastic modulus of a beetle wing membrane.Specimens were prepared bycarefully cutting a beetle hind wing into 3.0 mm by 7.0 mm segments (the gage length was 5 mm).We used a scanning electronmicroscope for a precise measurement of the thickness of the beetle wing membrane.The specimen was attached to a designedfixture to induce a uniform displacement by means of a micromanipulator.We used an ARAMISTM system based on the digitalimage correlation technique to measure the corresponding displacement of a specimen.The thickness of the beetle wing variedat different points of the membrane.The elastic modulus differed in relation to the membrane arrangement showing a structuralanisotropy;the elastic modulus in the chordwise direction is approximately 2.65 GPa,which is three times larger than the elasticmodulus in the spanwise direction of 0.84 GPa.As a result,the digital image correlation-based ARAMIS system was suc-cessfully used to measure the elastic modulus of a beetle wing.In addition to membrane’s elastic modulus,we considered thePoisson’s ratio of the membrane and measured the elastic modulus of a vein using an Instron universal tensile machine.Theresult reveals the Poisson’s ratio is nearly zero and the elastic modulus of a vein is about 11 GPa. | Tailie Jin Nam Seo Goo Sung-Choong Woo Hoon Cheol Park | 2009 | Journal of Bionic Engineering2009,6,3: | 4 |
| 12 | SECOND ORDER APPROXIMATION SOLUTION OF NONLINEAR LARGE DEFLECTION PROBLEMS OF YONGJIANG RAILWAY BRIDGE IN NINGBO显示文摘The solution and computational aspects on nonlinear deflection of Yongjiang Railway Bridge in Ningbo were investigated. An approximate iteration algorithm on nonlinear governing equation was presented, and the obtained results show that, if altitude difference and span of the riverbanks are taken as 5 meters and 100 meters, respectively, the maximum gradient in the middle of the bridge exceeds 5%, much larger than maximum allowance gradient in railway design code. Therefore, a new solution scheme for decreasing gradient of the bridge is put forward, that is, the altitude difference between two riverbanks can be decreased to about 1/10 of the initial magnitude by building roadbeds with 0 5% gradient and 1 kilometer length at two riverbanks. As a direct result, the deflection gradient of the railway bridge is much reduced and the value is between 0 5%~0 6%. | CHIEN Wei-zang(钱伟长) | 2002 | Applied Mathematics and Mechanics(English Edition)2002,23,5: | 3 |
| 13 | A methodology to determine the elastic properties of anisotropic rocks from a single uniaxial compression test显示文摘This paper introduces a new methodology to measure the elastic constants of transversely isotropic rocks from a single uniaxial compression test.We first give the mathematical proof that a uniaxial compression test provides only four independent strain equations.As a result,the exact determination of all five independent elastic constants from only one test is not possible.An approximate determination of the Young’s moduli and the Poisson’s ratios is however practical and efficient when adding the Saint-Venant relation as the fifth equation.Explicit formulae are then developed to calculate both secant and tangent definitions of the five elastic constants from a minimum of four strain measurements.The results of this new methodology applied on three granitic samples demonstrate a significant stress-induced nonlinear behavior,where the tangent moduli increase by a factor of three to four when the rock is loaded up to 20 MPa.The static elastic constants obtained from the uniaxial compression test are also found to be significantly smaller than the dynamic ones obtained from the ultrasonic measurements. | Morteza Nejati Marie Luise Texas Dambly Martin OSaar | 2019 | Journal of Rock Mechanics and Geotechnical Engineering2019,11,6: | 3 |
| 14 | Random field characterization of uniaxial compressive strength and elastic modulus for intact rocks显示文摘Rock properties exhibit spatial variabilities due to complex geological processes such as sedimentation,metamorphism, weathering, and tectogenesis. Although recognized as an important factor controlling the safety of geotechnical structures in rock engineering, the spatial variability of rock properties is rarely quantified. Hence, this study characterizes the autocorrelation structures and scales of fluctuation of two important parameters of intact rocks, i.e. uniaxial compressive strength(UCS) and elastic modulus(EM).UCS and EM data for sedimentary and igneous rocks are collected. The autocorrelation structures are selected using a Bayesian model class selection approach and the scales of fluctuation for these two parameters are estimated using a Bayesian updating method. The results show that the autocorrelation structures for UCS and EM could be best described by a single exponential autocorrelation function. The scales of fluctuation for UCS and EM respectively range from 0.3 m to 8.0 m and from 0.3 m to 8.4 m.These results serve as guidelines for selecting proper autocorrelation functions and autocorrelation distances for rock properties in reliability analyses and could also be used as prior information for quantifying the spatial variability of rock properties in a Bayesian framework. | Huaxin Liu Xiaohui Qi | 2018 | Geoscience Frontiers2018,9,6: | 3 |
| 15 | Influence of Deposition Temperature on the Splat Bonding and Mechanical Properties of Plasma-Sprayed Tungsten Coatings显示文摘The mechanical properties of thermally sprayed metallic coatings are limited by the bonding between splats.In this study,tungsten coatings were deposited at different deposition temperatures by controlling the substrate temperature through shrouded plasma spraying.The dependence of the splat bonding and mechanical properties of W coatings on deposition temperature was investigated.The results showed that the apparent porosity of the coatings decreased from 3.2%to 0.3%with the increase of the deposition temperature.The Young's modulus of W coating was significantly increased from 128 to 307 GPa as the deposition temperature increased from room temperature to 800°C.The microhardness of the coatings was less influenced by the deposition temperature.It was found that splat bonding across lamellae was formed when the deposition temperature was higher than 600°C compared to the obvious lamellae interface in the coatings deposited at temperatures lower than 600°C.The results evidently revealed that the mechanical properties of plasma-sprayed W coatings could be controlled through the splat bonding by altering deposition temperature. | Yang Guanjun Kang Xiaohu Li Chengxin Li Changjiu | 2012 | 稀有金属材料与工程2012,41,S1: | 3 |
| 16 | Dynamic properties of composite cemented clay显示文摘In this work, the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays. | 蔡袁强 梁旭 | 2004 | Journal of Zhejiang University-Science A(Applied Physics & Engineering)2004,5,3: | 3 |
| 17 | 银离子注入Mg-Ca-Zn合金在模拟体液中的耐腐蚀性研究(英文)显示文摘研究了Mg-1.0Ca-0.3Zn合金在银离子剂量为1.5×1017cm-2注入条件下,在模拟体液(simulated body flmd,SBF)中的耐腐蚀性.通过纳米压痕和三电极体系法对合金的表面硬度和弹性模量、在SBF中的极化曲线测定表明:经过银离子注入后,合金的表面硬度和pH值逐渐增加,加快了SBF溶液的碱化.Abstract:The corrosion resistance of Ag ion implanted with dose of 1.5×1017 cm-2 for Mg-1.0 Ca-0.3 Zn magnesium alloy in the simulated body fluid was investigated. The surface hardness and elastic modulus of the alloy and the polarization curve in the SBF were obtained by Nano Snick and three electrode system, respectively. The results indicate that the hardness and the elastic modulus are improved obviously after the implantation of Ag ions, the surface hardness reaches the maximum at a depth of 250 nm below the alloy surface. Meanwhile, the polarization resistance is strengthened, and consequently the corrosion resistance of the alloy is improved. Moreover, the pH value of the SBF within 48 h increases gradually and the alkalization of the SBF is accelerated. | 毛丽贺 王玉林 万怡灶 何芳 黄远 | 2010 | 稀有金属材料与工程2010,39,12: | 3 |
| 18 | Rotation Control of a 3-DOF Parallel Mechanism Driven by Pneumatic Muscle Actuators显示文摘The pneumatic muscle actuator(PMA)has many advantages,such as good flexibility,high power/weight ratio,but its nonlinearity makes it difficult to build a static mathematical model with high precision.A new method is proposed to establish the model of PMA.The concept of hybrid elastic modulus which is related to the static characteristic of PMA is put forward,and the energy conservation law is used to achieve the expression of the hybrid elastic modulus,which can be fitted out based on experimental data,and the model of PMA can be derived from this expression.At the same time,a 3-DOF parallel mechanism(a new bionic shoulder joint)driven by five PMAs is designed.This bionic shoulder joint adopts the structure of two antagonistic PMAs actualizing a rotation control and three PMAs controlling another two rotations to get better rotation characteristics.The kinematic and dynamic characteristics of the mechanism are analyzed and a new static model of PMA is used to control it.Experimental results demonstrate the effectiveness of this new static model. | LIU Kai CHEN Yining WU Yang XU Jiaqi WANG Yangwei GE Zhishang | 2019 | Transactions of Nanjing University of Aeronautics and Astronautics2019,36,2: | 2 |
| 19 | Elastic Modulus and Stress Analysis of Porous Titanium Parts Fabricated by Selective Laser Melting显示文摘The mismatch of elasticity modulus has limited the application of titanium alloys in medical implants,and porous structures have been proved effective to deal with this problem. However,the manufacturing of porous structures has been restricted from conventional technologies. In this study,selective laser melting( SLM) technology was employed to produce a set of Ti-6Al-4V porous samples based on cubic lattices with varying size of strut width from 200 μm to 600 μm. Then the compression tests were conducted to analyze the influence of the strut width on the elasticity modulus and the ultimate strength. The result shows both of them increases linearly with the growth of strut width or with the decrease of porosity,and the elasticity modulus of porous parts is largely reduced and actually meets the requirement of clinical application. Additionally,a finite element model was established to verify the un-uniform stress distribution of porous parts. It reveals that fractures always initially occur at the vertical struts along the force direction which suffer from the main deformation. | Junchao Li Yanyan Zang Wei Wang | 2016 | Journal of Harbin Institute of Technology(New Series)2016,23,2: | 2 |
| 20 | The Sensitive Properties of Hydrate Reservoirs Based on Seismic Stereoscopic Detection Technology显示文摘Higher-precision determinations of hydrate reservoirs, hydrate saturation levels and storage estimations are important for guaranteeing the ability to continuously research, develop and utilize natural gas hydrate resources in China. With seismic stereoscopic detection technology, which fully combines the advantages of different seismic detection models, hydrate formation layers can be observed with multiangle, wide-azimuth, wide-band data with a high precision. This technique provides more reliable data for analyzing the distribution characteristics of gas hydrate reservoirs, establishing velocity models, and studying the hydrate-sensitive properties of petrophysical parameters;these data are of great significance for the exploration and development of natural gas hydrate resources. Based on a velocity model obtained from the analysis of horizontal streamer velocity data in the hydrate-bearing area of the Shenhu Sea, this paper uses three VCs(longitudinal spacing of 25 m) and four OBSs(transverse spacing of 200 m) to jointly detect seismic datasets consisting of wave points based on an inversion of traveltime imaging sections. Accordingly, by comparing the differences between the seismic phases in the original data and the forward-modeled seismic phases, multiangle coverage constraint corrections are applied to the initial velocity model, and the initial model is further optimized, thereby improving the imaging quality of the streamer data. Petrophysical elastic parameters are the physical parameters that are most directly and closely related to rock formations and reservoir physical properties. Based on the optimized velocity model, the rock elastic hydrate-sensitive parameters of the hydrate reservoirs in the study area are inverted, and the sensitivities of the petrophysical parameters to natural gas hydrates are investigated. According to an analysis of the inversion results obtained from these sensitive parameters, λρ, Vp and λμ are simultaneously controlled by the bulk modulus and shear modulus, while Vs and μρ are controlled only by the shear modulus, and the latter two parameters are less sensitive to hydrate-bearing layers. The bulk modulus is speculated to be more sensitive than the shear modulus to hydrates. In other words, estimating the specific gravity of the shear modulus among the combined parameters can affect the results from the combined elastic parameters regarding hydrate reservoirs. | LIU Xueqin XING Lei QIN Zhiliang LIU Huaishan | 2020 | Acta Geologica Sinica(English Edition)2020,94,2: | 2 |