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| 1 | 固溶温度对激光立体成形GH4169高温合金组织和性能的影响(英文)显示文摘研究激光立体成形GH4169高温合金固溶处理后的组织,分析了固溶过程中合金元素的均匀化,并对材料显微硬度的变化做了讨论。结果表明,随固溶温度的升高,材料的晶界越来越清晰,经1000-1170°C固溶处理1h后材料发生再结晶,当固溶处理温度高于1100°C,有大量孪晶出现,晶粒相比沉积态显著细化,晶粒尺寸约200μm。合金元素的均匀化在1100°C保温1h后基本完成。显微硬度测试结果显示,材料的显微硬度值随固溶温度的升高而降低,在固溶温度低于1100°C时减小趋势较快,高于1100°C时减小趋势减缓。显微硬度的变化与材料中γ′和γ'相及δ相的形态和数量有关。1100°C是激光立体成形GH4169合金比较合适的固溶处理温度下限。 | 刘奋成 林鑫 赵卫卫 赵晓明 陈静 黄卫东 | 2010 | 稀有金属材料与工程2010，39，9： | 29 |
| 2 | Seismic wave input method for three-dimensional soil-structure dynamic interaction analysis based on the substructure of artificial boundaries显示文摘The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves. | Liu Jingbo Tan Hui Bao Xin Wang Dongyang Li Shutao | 2019 | Earthquake Engineering and Engineering Vibration2019，18，4： | 11 |
| 3 | An adaptive version of ghost-cell immersed boundary method for incompressible flows with complex stationary and moving boundaries显示文摘An adaptive version of immersed boundary method for simulating flows with complex stationary and moving boundaries is presented.The method employs a ghost-cell methodology which allows for a sharp representation of the immersed boundary.To simplify the implementation of the methodology,a volume-of-fluid method is introduced to identify the immersed boundary.In addition,the domain is spatially discretized using a tree-based discretization which is relatively simple to implement a fully flexible adaptive refinement strategy.Finally,the methodology is validated by comparing it with numerical and experimental results on three cases:(1) the flow passing a circular cylinder at Re=40 and Re=100,(2) a periodic oscillation of a circular cylinder in fluid at rest and(3) the self-propelled fish-like swimming at Re=6400. | WANG Liang1 & WU ChuiJie2,3 1 School of Science,PLA University of Science and Technology,Nanjing 211101,China 2 State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China 3 School of Aeronautics and Astronautics,Dalian University of Technology,Dalian 116024,China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，5： | 11 |
| 4 | Study on the stability and 3-dimensional character for natural convection in a rectangular cavity heated from below显示文摘Natural convection of air is numerically simulated in a 3-dimensional rectangular cavity heated from below using SIMPLE algorithm with a QUICK scheme.The results suggest that when all lateral walls are adiabatic,the fluid rolls occur along the long axis.When the Rayleigh number is smaller,the flow is of 2-dimensional character,and the rolls shapes are similar.The average Nusselt numbers in the central part of the cavity are similar.The average Nusselt numbers in the part near by the cavity are different.According to the comparison of 3-dimensional results with 2-dimensional results,the flow patterns and heat transfer in the central part of the cavity can be assumed as a 2-dimensional flow,While those in the part near by the cavity can not.With increasing Rayleigh number,the flow is 3-dimensional characteristic.The 3-dimensional result accords with the experimental result.When all lateral walls are adiabatic,the ten rolls occur along the long axis.But when lateral walls are heated or cooled,the rolls disappear along the long axis and two rolls occur along the short axis.The rotation direction of the rolls is reversed.When Rayleigh number is over some critical value,flow and heat transfer will be asymmetry,indicating unsteady oscillation occurs.By nonlinear analyses,it is shown that with increasing Rayleigh number,flow and heat transfer will change from steady state to unsteady state through HOPF bifurcation,and transition to chaos will occur through multi-periodical oscillation. | ZHAN NaiYan1,2,XU PeiWei1,SUN ShiMei,YANG Mo2 & LIU Jun3 1 Scool of Municipal and Environmental Engineering,Jilin Institute of Architectural and Civil Engineering,Changchun 130021,China 2 College of Power Engineering,University of Shanghai for Science and Technology,Shanghiai 200093,China 3 College of Power Engineering,Jilin University,Changchun 130000,China | 2010 | Science China(Technological Sciences)2010，53，6： | 9 |
| 5 | Characteristics of dry friction backward whirl—A self-excited oscillation in rotor-to-stator contact systems显示文摘In this paper,the response characteristics of dry friction backward whirl of a general rotor/stator model,which accounts for both the dynamics of the rotor and the stator as well as the friction and the deformation at the contact surfaces,are investigated.The existence boundaries and the whirl frequencies of the dry friction backward whirl are determined analytically.It is found that there are two or three existence boundaries of the dry friction backward whirl that usually form two existence regions,either standing completely separately,or overlapping each other partly,or one containing the other completely,depending upon the system parameters.The whirl frequencies in the two existence regions are quite different and may jump between the lower and the higher values with the variation of the rotating speed.The results have been found to have good correspondence in the related rotor/stator rubbing experiments. | JIANG Jun,SHANG ZhiYong & HONG Ling MOE Key Laboratory of Strength and Vibration,Xi’an Jiaotong University,Xi’an 710049,China | 2010 | Science China(Technological Sciences)2010，53，3： | 8 |
| 6 | Ni-Cr-W合金在1100℃的氧化膜演变(英文)显示文摘对新型Ni-Cr-W合金在1100℃下不同保温时间下的恒温氧化行为进行了研究。采用扫描电镜(SEM)以及能谱(EDS)对合金热暴露后的表面氧化膜形貌、元素含量以及合金基体的恶化情况进行了分析,表面氧化膜的相组成通过XRD进行确定。结果表明:在氧化初期(<3h),合金表面生成的单层氧化膜主要由Cr2O3组成,随着氧化时间的延长(>7h),在Cr2O3外逐渐形成了一层具有尖晶石结构的NiCr2O4。一旦外表面被均匀致密的尖晶石膜所覆盖,双层氧化膜NiCr2O4·Cr2O3便能有效的减慢合金基体被进一步氧化。合金亚表层的恶化形式包括晶界的内氧化、空洞以及无碳化物区的形成。合金中高的W含量并没有明显恶化合金的抗氧化性能。 | 黄晓晓 李金山 胡锐 柏广海 傅恒志 | 2010 | 稀有金属材料与工程2010，39，11： | 7 |
| 7 | Effect of the simultaneous application of a high static magnetic field and a low alternating current on grain structure and grain boundary of pure aluminum显示文摘Effect of the simultaneous application of a high static magnetic field and a low alternating electric current on the solidification structure of pure aluminum has been investigated. Results show that the refinement of the solidification structure is enhanced by the electric current under a certain magnetic field. However,when the magnetic field intensity exceeds a certain value, the refinement is impaired under a certain electric current. The observation by electron backscattered diffraction(EBSD) shows the complex fields have led to the increase of the low angle boundaries with the refinement. Moreover, the application of the static gradient magnetic field is capable of modifying the distribution of the refined grains. The above results may be attributed to the formation of the cavities during the electromagnetic vibration process and the high magnetic field. | Chengshuai Li Shaodong Hu Zhongming Ren Yves Fautrelle Xi Li | 2018 | Journal of Materials Science & Technology2018，34，12： | 7 |
| 8 | 百脉根类LATERAL ORGAN BOUNDARIES基因的分离及表达方式(英文)显示文摘植物顶端分生组织可分为中央区,周缘区和肋区。在植物胚后发育中,侧生器官产生于顶端分生组织的周缘区。顶端分生组织和侧生器官之间的边界的建立和维持是一个非常重要的发育过程,许多调节子参与控制这个过程。拟南芥的 LATERALORGANBOUNDARIES(LOB)基因具有独特的表达模式,其表达的范围与上述的边界区域重合。LOB基因隶属于一个大的基因家族——L O B 结构域基因家族。该家族编码的蛋白在 N 端具有一个保守的LOB结构域,该家族 LOB 基因以外的成员也参与拟南芥不同的发育过程。为了探讨在与拟南芥亲缘关系较远的豆科中 LOB 同源基因的功能,我们在豆科模式植物百脉根中分离了3 个 LOB 同源基因,命名为 LjLOB 基因,并用 RNA 原位杂交方法研究了这3个基因的表达模式。研究结果显示,L j L O B 1 和LjLOB3都强烈地在小叶原基的基部表达,这种表达模式可能与小叶原基和复叶原基之间的边界相关。而LjLOB4则在发育中的花芽不同轮之间的边界上表达。百脉根中这3 个基因具有不同的表达模式,强烈地提示它们的功能发生了分歧:L j L O B 1 和L j L O B 3 可能在复叶发育中具有重要功能;而LjLOB4 则可能参与了花的发育。 | 罗江虹 翁琳 罗达 | 2006 | 植物生理与分子生物学学报2006，32，2： | 6 |
| 9 | Stability of alpine timberline ecotone on Taibai Mountain,China显示文摘1IntroductionTaibaiMountain,whichextendsfrom33°49′31″to34°08′11″Nandfrom107°41′23″to107°51′40″E,isthehighestpeakofQinlingRang... | Cui Hai ting, Dai Jun hu, Tang Zhi yao, Huang Yong mei, Cao Yan li Department of Urban and Environmental Sciences, Peking University, Beijing 100871, China | 1999 | Journal of Environmental Sciences1999，11，2： | 6 |
| 10 | Welding solidification cracking susceptibility and behavior of a Ni-28W-6Cr alloy显示文摘Welding solidification cracking of alloys is associated with the range of solidification temperature that can be greatly affected by the amount of refractory metals and other additives. In this work, solidification cracking of Ni-28W-6Cr alloy with high W content was studied by gas tungsten arc welding, showing that the welding current, alloying elements and precipitates all affect the cracking susceptibility. The lengths of cracks increase linearly with the welding current in the range from 150 to 250 A. The relatively high cracking susceptibility is mainly attributed to the high content of Si, which tends to segregate with other elements including W, Cr, Mn as films or components with low melting point in the last solidification stage and weaken the binding force of grain boundaries. Moreover, the existence of precipitated continuous eutectic M_6C carbides in the grain boundaries also acts as nucleation sites of crack initiation, and the cracks often propagate along solidification grain boundary. | Shuangjian Chen Xiang-Xi Ye D.K.L.Tsang Li Jiang Kun Yu Chaowen Li Zhijun Li | 2019 | Journal of Materials Science & Technology2019，35，1： | 5 |
| 11 | Surface defect engineering of metal oxides photocatalyst for energy application and water treatment显示文摘Despite metal oxides offer excellent characteristics in the field of photocatalysis,they often suffer from charge carrier recombination as well as limited visible response,which indeed reduce the charge kinetics process and ultimately reduce the photocatalytic output.Defect engineering is a sophisticated technique to manufacture defects and alter the geometric structure and chemical environment of the host.The present study provides an all-inclusive outline of recent developments on the classification of metal oxide defects based on the dimensions of a host crystal lattice.Precisely,surface modification of metal oxides through 0D(point),1D(line),2D(planar),and 3D(volume)defects with their subsequent mechanism and impact on photocatalytic performance are presented.By wisely amending the morphology(cores along with the shells)and electronic structure of metal oxide photocatalysts(TiO_(2),ZnO,Bi_(2)O_(3),Fe_(2)O_(4) etc.)through different attuned and veritable approaches,their photocatalytic activity can be substantially improved.Optimal studies on defect engineering not only expose the altered physicochemical features but also modulate the electron-hole pair dynamics,stability,and active radical production for various photoredox reactions.Altered atomic,as well as electronic configuration,facilitated a photocatalyst material to have different optical features,adsorption properties along with improved carrier transfer as well as isolation rate.Thus,the systematic exploration of photocatalytic rudiments of defect rich metal oxide for various applications such as H_(2) evolution,CO_(2) reduction,pollutant degradation,and bacterial disinfection could bring significant research advancement in this field. | Pankaj Raizada Vatika Soni Abhinandan Kumar Pardeep Singh Aftab Aslam Parwaz Khan Abdullah M.Asiri Vijay Kumar Thakur Van-Huy Nguyen | 2021 | Journal of Materiomics2021，7，2： | 4 |
| 12 | Low-Angle Grain Boundaries in Sublimation Grown 6H-SiC Crystals显示文摘High-resolution X-ray diffractometry (HRXRD) was used to assess the quality of 6H-SiC crystals grown by sublimation method. The results show the occurrence of low-angle grain boundaries (LB) is close relative to the inclination of the crystal interface. At the central faceted region with 0° inclination the crystal is of high structural perfection. However, at the region close to the facet with less than 5° inclination LB occurs slightly and at the region close to the peripheral polytype ring with more than 5° inclination LB defect occurs heavily. The density of LB can be drastically reduced by decreasing radial temperature gradient that determines the shape of the crystal growth interface. | Jiang Shouzhen Li Xianxiang Dong Jie Chen Xiufang Xu Xiangang Hu Xiaobo | 2006 | Journal of Rare Earths2006，24，z1： | 3 |
| 13 | “連結”之後:評 Kristina Kleutghen,Imperial Illusions:Crossing Pictorial Boundaries in the Qing Palaces.Washington,D.C.:University of Washington Press,2015显示文摘全球史浪潮下的清宫熱正如許多學者已經留意到,近二十年來歷史學界最值得關注的現象之一,大概是全球史的興起。~1而這波全球化研究的轉向及其影響所及,不僅局限於歷史學的領域,同時也衝擊着藝術史的研究。~2不同於之前同樣以全球爲範疇的世界史研究,此全球史視世界爲一彼此連動的整體,强調地球村中千絲萬縷的關聯,任何一個區域的變化都可能帶來牽一髪而動全身的全球效應。 | 賴毓芝 | 2018 | 浙江大学艺术与考古研究2018，，1： | 2 |
| 14 | Grain size-dependent electrical resistivity of bulk nanocrystalline Gd metals显示文摘The electrical resistivity of the as-consolidated and coarse-grained bulk gadolinium(Gd) metals was studied in the temperature range of 3-315K.The experimental results showed that with decrease in the grain size of Gd grains from micrometer to nanometer range,the room temperature electrical resistivity increased from 209.7 to 333.0 μΩcm,while the electrical resistivity at the low temperature of 3K was found to increase surprisingly from 16.5 to 126.3 μΩcm.The room temperature coefficient resistivity(TCR) values were obtained as 39.2×10-3,5.51×10-3 and 33.7×10-3K-1.The ratios of room temperature to residual resistivity [RRR=ρ(300K)/ρ(3K)] are 2.64,11.0,respectively,for the as-consolidated samples at 280℃ and 700℃ with respect to that of the coarse-grained sample.All results indicate the remarkable influence of the nanostructure on the electrical resistivity of Gd due to the finite size effect and large fraction of grain boundaries. | Hong Zeng Ying Wu Jiuxing Zhang Chunjiang Kuang Ming Yue Shaoxiong Zhou | 2013 | Progress in Natural Science:Materials International2013，23，1： | 2 |
| 15 | Effect of the frequency of high-angle grain boundaries on the corrosion performance of 5wt%Cr steel in a CO2 aqueous environment显示文摘The corrosion behavior of 5 wt%Cr steel tempered at different temperatures was investigated by immersion testing and electrochemical testing in a CO_2 aqueous environment. When the tempering temperature exceeded 500℃, the corrosion rate increased. The corrosion layers consisted of Cr-rich compounds, which affected the corrosion behaviors of the steels immersed in the corrosive solution. The results of electrochemical experiments demonstrated that 5 wt%Cr steels with different microstructures exhibited pre-passivation characteristics that decreased their corrosion rate. Analysis by electron back-scattered diffraction showed that the frequency of high-angle grain boundaries(HAGBs) and the corrosion rate were well-correlated in specimens tempered at different temperatures. The corrosion rate increased with increasing HAGB frequency. | Hui-bin Wu Tao Wu Gang Niu Tao Li Rui-yan Sun Yang Gu | 2018 | International Journal of Minerals,Metallurgy and Materials2018，25，3： | 2 |
| 16 | Significance of ichnofossils to genetic stratigraphy——Examples from the Cretaceous of Alberta, Canada显示文摘Trace fossils represent both sedimentological and paleontological entities, representing a unique blending of potential environmental indicators in the rock record. Trace fossils and trace fossil suites can be employed effectively to aid in the recognition of various discontinuity types and to assist in their genetic interpretation. Ichnology may be employed to resolve surfaces of strati-graphic significance in two main ways: 1) through the identification of discontinuities using substrate-controlled ichnofacies, and 2) through careful analysis of vertical softground (penecontem-poraneous) ichnologic successions (analogous to facies successions). Ichnological analysis is a valuable tool in genetic stratigraphic studies. Integrating the data derived from substrate-controlled ichnofacies with paleoecological data from vertical ichnologic successions greatly enhances the recognition and interpretation of a wide variety of stratigraphic surfaces. When this is coupled with conventional facies analysis and | S.George Pemberton James A.MacEachern Murray K.Gingras 张建平 | 2000 | Science China Earth Sciences2000，43，5： | 2 |
| 17 | Interfacial microstructure and mechanical properties of Ti-6Al-4V/Al7050 joints fabricated using the insert molding method显示文摘Ti-6Al-4V/Al7050 joints were fabricated by a method of insert molding and corresponding interfacial microstructure and mechanical properties were investigated. The interfacial thickness was sensitive to holding temperature during the first stage, and a good metallurgical bonding interface with a thickness of about 90 μm can be obtained at 750°C. X-ray diffraction, transmission electron microscopy, and thermodynamic analyses showed that the interface mainly contained intermetallic compound TiAl_3 and Al matrix. The joints featured good mechanical properties, i.e., shear strength of 154 MPa, tensile strength of 215 MPa, and compressive strength of 283 MPa, which are superior to those of joints fabricated by other methods. Coherent boundaries between Al/TiAl_3 and TiAl_3/Ti were confirmed to contribute to outstanding interfacial mechanical properties and also explained constant fracture occurrence in the Al matrix. Follow-up studies should focus on improving mechanical properties of the Al matrix by deformation and heat treatment. | Hong-xiang Li Xin-yu Nie Zan-bing He Kang-ning Zhao Qiang Du Ji-shan Zhang Lin-zhong Zhuang | 2017 | International Journal of Minerals,Metallurgy and Materials2017，24，12： | 2 |
| 18 | Effects of helium implantation on mechanical properties of (Al_(0.31)Cr_(0.20)Fe_(0.14)Ni_(0.35)) O high entropy oxide films显示文摘It is widely accepted that helium(He) bubbles can prevent dislocations from moving and causing hardening and embrittlement of the material. However, He can affect the mechanical properties of materials in various ways. In this work,ultrafine nanocrystal high entropy oxide(HEO) films with He implantation are prepared by using a radio frequency(RF)reactive magnetron sputtering system to investigate the effects of He bubbles located at grain boundary on the mechanical properties of the films. The mechanical properties of the HEO films are investigated systematically via nanoindentation measurements. The results indicate that the grain boundary cavities induced by He implantation can degrade the hardness,the elastic modulus, and the creep resistance of the HEO films. The mechanical properties of the HEO films are sensitive to the interaction between the He bubbles and the dominating defects. | 杨朝明 张坤 裘南 张海斌 汪渊 陈坚 | 2019 | Chinese Physics B2019，28，4： | 1 |
| 19 | Study on rare earth electrolyte of SDC显示文摘The grain boundaries of polycrystalline oxygen ion conductors presented a blocking effect on the oxygen ionic transport across them. It was found that the apparent specific grain boundary conductivity was 2-3 orders of magnitude lower than the bulk conductivity in the temperature range of 200-500 °C for normal purity Ce0.85Sm0.15O1.925 (SDC) with an average grain size of 320-580 nm. The apparent specific grain boundary conductivity increased with decreasing average grain size. It was found that the space charge potential was nearly independent of grain size, and the reason was analyzed. The increase of the conduction path width was responsible for the increase in the apparent specific grain boundary conductivity. | 严端廷 刘晓梅 刘倩 王浩鹏 徐江红 齐松 郑敏章 苏文辉 | 2010 | Journal of Rare Earths2010，28，6： | 1 |
| 20 | Earth's deformation due to the dynamical perturbations of the fluid outer core显示文摘The elasto-gravitational deformation response of the Earth's solid parts to the perturbations of the pressure and gravity on the core-mantle boundary (CMB) and the solid inner core boundary (ICB), due to the dynamical behaviors of the fluid outer core (FOC), is discussed. The internal load Love numbers, which are formulized in a general form in this study, are employed to describe the Earth's deformation. The preliminary reference Earth model (PREM) is used as an example to calculate the internal load Love numbers on the Earth's surface, CMB and ICB, respectively. The characteristics of the Earth's deformation variation with the depth and the perturbation periods on the boundaries of the FOC are also investigated. The numerical results indicate that the internal load Love numbers decrease quickly with the increasing degree of the spherical harmonics of the displacement and depend strongly on the perturbation frequencies, especially on the high frequencies. The results, obtained in this work, can be used to construct the boundary conditions for the core dynamics of the long-period oscillations of the Earth's fluid outer core. | XU Jian-qiao (徐建桥) SUN He-ping (孙和平) | 2002 | Acta Seismologica Sinica(English Edition)2002，15，4： | 1 |
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