|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | 应用神经网络和多元回归技术预测森林产量显示文摘应用传统统计技术常会因样本小和测量数据不符某种分布而受到限制.本文评价一种前馈型神经网络算法以预测落叶阔叶林产量.另外,还介绍一种由定性变为定量的数据变换方法,以用相对小的样本建立多元回归预测模型.数据变换方法有助于改善多元回归模型的预测效果.在本实验的条件下。 | 浦瑞良 宫鹏 R.Yang | 1999 | 应用生态学报1999，10，2： | 28 |
| 2 | Molecular Dynamics Simulation of Tensile Deformation and Fracture of γ-TiAl with and without Surface Defects显示文摘Molecular dynamics simulation of uniaxial tension along [001] has been performed to study the influence of various surface defects on the initiation of plastic deformation and fracture of γ-TiAl single crystals.The results indicate that brittle fracture occurs in perfect bulk; surfaces and edges will be detrimental to the strength of materials and provide dislocation nucleation site. The defects on surfaces and edges cause further weakening with various effects depending on defect type, size, position and orientation,while the edge dimples are the most influential. For γ-TiAl rods with surface dimples, dislocations nucleate from an edge of the rod when dimples are small, dimple dislocation nucleation occurs only when the dimples are larger than a strain rate dependent critical size. The dislocations nucleated upon [001]tension are super dislocations with Burger vectors <011] or 1/2 < 112] containing four 1/6 < 112 > partials. The effects of surface scratches are orientation and shape sensitive. Scratches parallel to the loading direction have little influence, while sharp ones perpendicular to the loading direction may cause crack and thus should be avoided. This simulation also shows that, any type of surface defect would lower strength,and cause crack in some cases. But some may facilitate dislocation nucleation and improve ductility of TiAl if well controlled. | H.N.Wu D.S.Xu H.Wang R.Yang | 2016 | Journal of Materials Science & Technology2016，32，10： | 9 |
| 3 | Microstructures and Hardness Properties for β-Phase Ti-24Nb-4Zr-7.9Sn Alloy Fabricated by Electron Beam Melting显示文摘Atomized,pre-alloyed Ti—24Nb—4Zr—7.9Sn(wt%) powder was used to fabricate solid,prototype components by electron beam melting(EBM).Vickers microindentation hardness values were observed to average 2 GPa for the precursor powder and 2.5 GPa for the solid,EBM-fabricated products.The powder and solid product microstructures were examined by optical and electron microscopy.X-ray diffraction analyses showed that they had bcc β-phase microstructure.However,it was found by transmission electron microscopy that the EBM-fabricated product had plate morphology with space ~ 100—200 nm.Although the corresponding selected area diffraction patterns can be indexed by β-phase plus α '-martensite with orthorhombic crystal structure,the dark-field analyses failed to observe the a'-martensite.Such phenomenon was also found in deformed gum metals and explained by stress-induced diffusion scattering due to phonon softening. | J.Hernandez S.J.Li E.Martinez L.E.Murr X.M.Pan K.N.Amato X.Y.Cheng F.Yang C.A.Terrazas S.M.Gaytan Y.L.Hao R.Yang F.Medina R.B.Wicker | 2013 | Journal of Materials Science & Technology2013，29，11： | 8 |
| 4 | Mechanical properties and deformation mechanisms of Ti-3Al-5Mo-4.5V alloy with varied β phase stability显示文摘Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined. | Q.Xue Y.J.Ma J.F.Lei R.Yang C.Wang | 2018 | Journal of Materials Science & Technology2018，34，12： | 8 |
| 5 | Evolution of microstructure and phase composition of Ti-3Al-5Mo-4.5V alloy with varied β phase stability显示文摘The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α ' martensite, which has the following orientation relationships: [111]β//[110]α',[100]p//[100]α ' and [-110]p//[00-1]α' with respect to the β matrix. | Q.Xue Y.J.Ma J.F.Lei R.Yang C.Wang | 2018 | Journal of Materials Science & Technology2018，34，12： | 8 |
| 6 | Effect of Base Material on Microstructure and Texture Evolution of a Ti–6Al–4V Electron-Beam Welded Joint显示文摘The effect of base material(BM) on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains was studied by advanced electron backscattered diffraction data processing. The inhomogeneity of microstructure within welded joint was formed due to the different microstructures of BM. By comparing microstructure details of the welded joint, including microstructure morphology and crystallographic orientation with those of the base material, it can be found that both the microstructure morphology and crystallographic orientation of the EBW joint would be controlled by BM. | G.Q.Wang Z.B.Zhao B.B.Yu J.R.Liu Q.J.Wang J.H.Zhang R.Yang J.W.Li | 2017 | Acta Metallurgica Sinica(English Letters)2017，30，5： | 6 |
| 7 | Distinct dendritic α phase emerging on the surface of primary α phase in a compressed near-α titanium alloy显示文摘The characteristic of the surface morphology of primary α phase was studied in a deformed near-α titanium alloy. Dendritic α phase emerged on the surfaces of primary α phase when the alloy was air-cooled in α + β phase field after deformation. The dendritic α grain has the same orientation with its original primary α grain. The formation of the dendritic α phase could be explained by interface instability in epitaxial growth process of the primary α phase. The dislocations induced by deformation could facilitate the formation of dendritic α phase leading to the dendritic α phase and more obvious with the increase of strain. The growth of dendritic α phase was finally limited by the nucleation of second α phase with cooling. | Z.Liu Z.B.Zhao J.R.Liu Q.J.Wang R.Yang | 2018 | Journal of Materials Science & Technology2018，34，4： | 3 |
| 8 | Structural and functional variations of phytoplankton communities in the face of multiple disturbances显示文摘The global decline of freshwater biodiversity caused by climate change and human activities are supposed to disrupt ecosystem services related to water quality and alter the structure and function of aquatic communities across space and time,yet the effects of the combination of these factors on plankton community ecosystem has received relatively little attention.This study aimed to explore the impacts of disturbances(e.g.human activity,temperature,precipitation,and water level)on phytoplankton community structure(i.e.community evenness and community composition)and function(i.e.resource use efficiency)in four subtropical reservoirs over 7 years from 2010 to 2016.Our results showed that community turnover(measured as community dissimilarity)was positively related to disturbance frequency,but no significant correlation was found between phytoplankton biodiversity(i.e.evenness)and disturbance frequency.Phytoplankton resource use efficiency(RUE=phytoplankton biomass/total phosphorus)was increased with a higher frequency of disturbance with an exception of cyanobacteria.The RUE of Cyanobacteria and diatoms showed significantly negative correlations with their community evenness,while the RUE of Chlorophyta exhibited a positive correlation with their community turnover.We suggest that multiple environmental disturbances may play crucial roles in shaping the structure and functioning of plankton communities in subtropical reservoirs,and mechanism of this process can provide key information for freshwater uses,management and conservation. | Jun R.Yang Xiaoqing Yu Huihuang Chen Yi-Ming Kuo Jun Yang | 2021 | Journal of Environmental Sciences2021，33，2： | 2 |
| 9 | Ability to detect and locate gross errors on DEM matching algorithm显示文摘Digital elevation model(DEM)matching techniques have been extended to DEM deformation detection by substituting a robust estimator for the least squares estimator,in which terrain changes are treated as gross errors.However,all existing methods only emphasise their deformation detecting ability,and neglect another important aspect:only when the gross error can be detected and located,can this system be useful.This paper employs the gross error judgement matrix as a tool to make an in-depth analysis of this problem.The theoretical analyses and experimental results show that observations in the DEM matching algorithm in real applications have the ability to detect and locate gross errors.Therefore,treating the terrain changes as gross errors is theoretically feasible,allowing real DEM deformations to be detected by employing a surface matching technique. | T.Zhang M.Cen Z.Ren R.Yang Y.Feng J.Zhu | 2010 | International Journal of Digital Earth2010，3，1： | 2 |
| 10 | Kant and G(o)del on objectivity of mathematical truth显示文摘 | R.Yang | | 0，，： | 1 |
| 11 | Poly(ether ether ketone) composites reinforced by short carbon fibers and zirconium dioxide nanoparticles: Mechanical properties and sliding wear behavior with water lubrication显示文摘 | Y. J.Zhong G. Y.Xie G. X.Sui R.Yang | 2010 | J Appl Polym Sci2010，，3： | 1 |
| 12 | 查看详情显示文摘 | Huang M.H Mao S Feick H Yan H.Q. Wu Y.Y. Kind H. Weber E. Russo R.Yang P.D | | 0，，： | 1 |
| 13 | 查看详情显示文摘 | R.Yang L.Zhang Y.Wang Z.Shi D.Shi H.Gao E.Wang and G.Zhang | | 0，，36： | 1 |
| 14 | Novel transcatheter aortic heart valves exhibiting excellent hemodynamic performance and low-fouling property显示文摘Transcatheter aortic heart valves(TAHVs) have been widely used for aortic valve replacements, with less trauma and lower clinical risk compared with traditional surgical heart valve replacements. In the present study, composites of poly(ethylene glycol) diacrylate(PEGDA) hydrogels and anisotropic highshrinkage polyethylene terephthalate/polyamide6(PET-PA6) fabric(PEGDA/PET-PA6) were fabricated as artificial heart valve leaflets. Dynamic mechanical analyses(DMA) indicated that PEGDA/PET-PA6 composites possessed anisotropic mechanical properties(i.e., storage moduli ~23.30 ± 1.36 MPa parallel to the aligned fabric fibers and ~9.68 ± 0.90 MPa perpendicular to the aligned fibers at 1 Hz) that were comparable to aortic valve leaflets. The PEGDA/PET-PA6 composites with smooth surfaces were highly hydrophilic(contact angle ~41.6°± 3.8°) and had low-fouling properties without platelet adhesion,suggesting a low risk of thrombogenicity when they interacted with blood. Furthermore, transcatheter aortic heart valves were fabricated using nitinol self-expanding frames and PEGDA/PET-PA6 composites as artificial leaflets, which presented excellent hemodynamic performance with a large orifice area(1.75cm2) and low regurgitation(3.41%), thus meeting the requirements of ISO 5840-3 standard. Therefore,PEGDA/PET-PA6 composites had suitable mechanical properties, good biocompatibility, and low-fouling properties, indicating that they might be used for TAHVs in the future. | F.Guo K.Jiao Y.Bai J.Guo Q.Chen R.Yang X.Zhang | 2019 | Journal of Materials Science & Technology2019，35，1： | 1 |
| 15 | Deformation behaviors of as-built and hot isostatically pressed Ti-6Al-4V alloys fabricated via electron beam rapid manufacturing显示文摘The deformation behavior of as-built and hot isostatically pressed(HIP)Ti-6Al-4V alloys fabricated using electron beam rapid manufacturing(EBRM)were investigated in this work.The deformation characteristics were characterized using a laser scanning confocal microscope and electron back-scattered diffraction(EBSD).In the as-built sample,prismatic slip was the main mode of deformation,as well as a small amount of basal slip and cross-slip.Some planar slip lines with large length scales were observed across severalαlamellae.After hot isostatical pressing,prismatic and basal slip were the main mode of deformation,accompanied by abundant cross-slip and multiple slip,and most of the slip lines were blocked within an a lamellae.These differences in deformation behavior were associated with the coarsening of a laths and the more retained p phase after HIP compared to the as-built alloy.More cross-slip and multiple slip can lead to superior elongation-to-failure and a greater strain hardening effect in the HIP alloy compared to the as-built sample. | Z.Liu Z.B.Zhao J.R.Liu L.Wang S.X.Zhu G.Yang S.L Gong Q.J.Wang R.Yang | 2019 | Journal of Materials Science & Technology2019，35，11： | 1 |
| 16 | 查看详情显示文摘 | Z.C.Wen R.Yang H.He | | 0，，： | 1 |
| 17 | Hydrogen Inhalation Ameliorates Oxidative Stress in Transplantation Induced Intestinal Graft Injury显示文摘 | B. M.Buchholz D. J.Kaczorowski R.Sugimoto R.Yang Y.Wang T. R.Billiar K. R.McCurry A. J.Bauer A.Nakao | 2008 | American Journal of Transplantation2008，，10： | 1 |
| 18 | Dislocation self-interaction in TiAl:Evolution of super-dislocation dipoles revealed by atomistic simulations显示文摘As one of the fundamental outcomes of dislocation self-interaction,dislocation dipoles have an important influence on the plastic deformation of materials,especially on fatigue and creep.In this work,superdislocation dipoles inγ-TiAl andα_(2)-Ti_(3)Al were systematically investigated by atomistic simulations,with a variety of dipole heights,orientations and annealing tempe ratures.The results indicate that non-screw super-dipoles transform into locally stable dipolar or reconstructed cores at low temperature,while into isolated or interconnected point defect clusters and stacking fault tetrahedra at high temperature via short-range diffu sion.Non-screw super-dipoles inγ-TiAl andα_(2)-Ti_(3)Al exhibit similar features as fcc and hcp metals,respectively.Generally,over long-term annealing where diffusion is significant,60°superdipoles inγ-TiAl are stable,whereas the stability of super-dipoles inα2-Ti3 Al increases with dipole height and orientation angle.The influence on mechanical properties can be well evaluated by integrating these results into mesoscale or constitutive models. | Z.Zhen H.Wang C.Y.Teng C.G.Bai D.S.Xu R.Yang | 2021 | Journal of Materials Science & Technology2021，，10： | 0 |
| 19 | Ordering-induced Elinvar effect over a wide temperature range in a spinodal decomposition titanium alloy显示文摘Temperature-independent elastic modulus is termed as Elinvar effect,which is available by tuning the continuous spin transition of ferromagnetic alloys via composition optimization and the first-order martensitic transformation of shape memory alloys via plastic deformation.However,these reversible mechanisms are restricted generally in a narrow temperature range of less than 300 K.Here reports,by tuning a spinodal decomposition in a Ti-Nb-based titanium alloy via aging treatment,both the Elinvar effect in a wide temperature range of about 500 K and a high strength-to-modulus ratio of about 1.5%can be obtained by a continuous and reversible crystal ordering mechanism.The results demonstrate that the alloy aged at 723 K for 4 h has a nanoscale plate-like modulatedβ+α'two-phase microstructure and its elastic modulus keeps almost constant from 100 to 600 K.Synchrotron and in-situ X-ray diffraction measurements reveal that the crystal ordering parameter of theα'phase increases linearly with temper-ature from 0.88 at 133 K to 0.97 at 523 K but its volume fraction keeps a constant of about 33.8%.This suggests that the continuous ordering of theα'phase toward the high modulusαphase induces a posi-tive modulus-temperature relation to balance the negative relation of the elastically stableβphase.The aged alloy exhibits a high yield strength of 1200 MPa,good ductility of 16%and a high elastic admissible strain of 1.5%.Our results provide a novel strategy to extend the Elinvar temperature range and enhance the strength by tuning the crystal ordering of decomposition alloys. | D.L.Gong H.L.Wang S.H.Hao P.Liu X.Yang Y.N.Jiang W.J.Wang K.Lin B.Li K.Du Y.D.Wang R.Yang Y.L.Hao | 2023 | Journal of Materials Science & Technology2023，，19： | 0 |
| 20 | Tuning thermal expansion by a continuing atomic rearrangement mechanism in a multifunctional titanium alloy显示文摘As to multifunctional titanium alloys with high strength and low elastic modulus, thermal training is crucial to tune their thermal expansion from positive to negative, resulting in a novel linear expansion which is stable in a wide temperature range. Aided by the high-order Hooke's law of elastic solids,a reversible atomic rearrangement mechanism was proposed to explain the novel findings which are unexpected from typical shape memory alloys. To confirm this continuous mechanism, a Ti-Nb based alloy, which possesses a nanoscale spongy microstructure consisting of the interpenetrated Nb-rich and Nb-lean domains produced by spinodal decomposition, was used to trace the crystal structure change by in-situ high energy synchrotron X-ray diffraction analyses. By increasing exposure time, the overlapped diffraction peaks can be separated accurately. The calculated results demonstrate that, in the nanoscale Nb-lean domains, the crystal structure parameters vary linearly with changing temperature along the atomic pathway of the bcc-hcp transition. This linear relationship in a wide temperature range is unusual for first-order martensitic shape memory alloys but is common for Invar alloys with high-order spin transitions. Furthermore, the alloy exhibits smooth DSC curves free of transformation-induced heat peaks observed in shape memory alloys, which is consistent with the proposed mechanism that the reversible transition is of high-order. | D.L.Gong H.L.Wang E.G.Obbard S.J.Li R.Yang Y.L.Hao | 2021 | Journal of Materials Science & Technology2021，，21： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员