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Modeling the Interaction between Vacancies and Grain Boundaries during Ductile Fracture
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作者 Mingjian Li Ping Yang Pengyang Zhao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期2019-2034,共16页
The experimental results in previous studies have indicated that during the ductile fracture of pure metals,vacancies aggregate and form voids at grain boundaries.However,the physical mechanism underlying this phenome... The experimental results in previous studies have indicated that during the ductile fracture of pure metals,vacancies aggregate and form voids at grain boundaries.However,the physical mechanism underlying this phenomenon remains not fully understood.This study derives the equilibrium distribution of vacancies analytically by following thermodynamics and the micromechanics of crystal defects.This derivation suggests that vacancies cluster in regions under hydrostatic compression to minimize the elastic strain energy.Subsequently,a finite element model is developed for examining more general scenarios of interaction between vacancies and grain boundaries.This model is first verified and validated through comparison with some available analytical solutions,demonstrating consistency between finite element simulation results and analytical solutions within a specified numerical accuracy.A systematic numerical study is then conducted to investigate the mechanism that might govern the micromechanical interaction between grain boundaries and the profuse vacancies typically generated during plastic deformation.The simulation results indicate that the reduction in total elastic strain energy can indeed drive vacancies toward grain boundaries,potentially facilitating void nucleation in ductile fracture. 展开更多
关键词 Ductile fracture VACANCY grain boundary MICROMECHANICAL finite element method
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Effects of Fe solid solute on grain boundaries of bi-crystal Cu: A molecular dynamics simulation
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作者 Shuohan Yang Hongwei Bao +3 位作者 Huizhong Bai Yan Li Haodong Xu Fei Ma 《Nano Materials Science》 EI CAS CSCD 2024年第1期86-95,共10页
Grain boundaries(GBs)play a crucial role on the structural stability and mechanical properties of Cu and its alloys.In this work,molecular dynamics(MD)simulations are employed to study the effects of Fe solutes on the... Grain boundaries(GBs)play a crucial role on the structural stability and mechanical properties of Cu and its alloys.In this work,molecular dynamics(MD)simulations are employed to study the effects of Fe solutes on the formation energy,excess volume,dislocations and melting behaviors of GBs in CuFe alloys.It is illustrated that Fe solute affects the structural stability of Cu GBs substantially,the formation energy of GBs is reduced,but the thickness and melting point of GBs are increased,that is,the structural stability of Cu GBs is significantly improved owing to the Fe solutes.A strong scaling law exists between the formation energy,excess volume,thickness and melting point of GBs.Therefore,Fe solid solute plays an important role in the characteristics of GBs in bi-crystal Cu. 展开更多
关键词 CuFe alloy Grain boundary Structural stability MD simulations
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Extensive identification of landslide boundaries using remote sensing images and deep learning method
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作者 Chang-dong Li Peng-fei Feng +3 位作者 Xi-hui Jiang Shuang Zhang Jie Meng Bing-chen Li 《China Geology》 CAS CSCD 2024年第2期277-290,共14页
The frequent occurrence of extreme weather events has rendered numerous landslides to a global natural disaster issue.It is crucial to rapidly and accurately determine the boundaries of landslides for geohazards evalu... The frequent occurrence of extreme weather events has rendered numerous landslides to a global natural disaster issue.It is crucial to rapidly and accurately determine the boundaries of landslides for geohazards evaluation and emergency response.Therefore,the Skip Connection DeepLab neural network(SCDnn),a deep learning model based on 770 optical remote sensing images of landslide,is proposed to improve the accuracy of landslide boundary detection.The SCDnn model is optimized for the over-segmentation issue which occurs in conventional deep learning models when there is a significant degree of similarity between topographical geomorphic features.SCDnn exhibits notable improvements in landslide feature extraction and semantic segmentation by combining an enhanced Atrous Spatial Pyramid Convolutional Block(ASPC)with a coding structure that reduces model complexity.The experimental results demonstrate that SCDnn can identify landslide boundaries in 119 images with MIoU values between 0.8and 0.9;while 52 images with MIoU values exceeding 0.9,which exceeds the identification accuracy of existing techniques.This work can offer a novel technique for the automatic extensive identification of landslide boundaries in remote sensing images in addition to establishing the groundwork for future inve stigations and applications in related domains. 展开更多
关键词 GEOHAZARD Landslide boundary detection Remote sensing image Deep learning model Steep slope Large annual rainfall Human settlements INFRASTRUCTURE Agricultural land Eastern Tibetan Plateau Geological hazards survey engineering
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Formation mechanism of co-axial grain boundaries in a Mg alloy
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作者 Zhen Peng Yi Liu +7 位作者 Lirong Xiao Yue Yang Bo Gao Mengning Xu Zhaohua Hu Yandong Yu Xuefei Chen Hao Zhou 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第3期1094-1101,共8页
Due to the insufficient slip systems in hexagonal close-packed structure,twinning is frequently activated to support stable plastic deformation of Mg alloy.In this work,we found four typical twin-like interfaces with ... Due to the insufficient slip systems in hexagonal close-packed structure,twinning is frequently activated to support stable plastic deformation of Mg alloy.In this work,we found four typical twin-like interfaces with misorientations of 102°,109°,142°and 149°,respectively,which had not only a shared[1120]zone axis of neighboring grains,but also overlapped diffraction spots similar to twins.However,highresolution transmission electron microscope(HRTEM)analysis revealed that the interfaces in real space deviated from the supposed twinning planes in reciprocal space,i.e.their overlapped diffraction spots.We clarified that the incoherent interfaces were co-axial grain boundaries(CGBs).Additionally,a special angle ofθ,close to 90°,between the interface and one side of basal plane,was frequently formed in CGBs.We proposed that interaction of multiple twinning contributes to the formation of CGBs,and theθis formed due to alternative tensile and compression twinning under a uniaxial loading. 展开更多
关键词 INTERFACE TWINNING Tilt boundaries TEM Formation mechanism
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Spatial Control of Lithium Deposition by Controlling the Lithiophilicity with Copper(Ⅰ)Oxide Boundaries
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作者 Ju Ye Kim Oh B.Chae +8 位作者 Gukbo Kim Woo-Bin Jung Sungho Choi Do Youb Kim San Moon Jungdon Suk Yongku Kang Mihye Wu Hee-Tae Jung 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第5期183-191,共9页
Spatial control of lithium deposition is the most important issue in lithium-metal batteries because of the considerable control of lithium dendrite suppression via the uniform distribution of Li^(+)flux.Although seed... Spatial control of lithium deposition is the most important issue in lithium-metal batteries because of the considerable control of lithium dendrite suppression via the uniform distribution of Li^(+)flux.Although seed materials are crucial for the behavior of lithium deposition,in-depth studies on their physical and chemical control have not been conducted.Here,we describe a new design of seed structure comprising a wrinkled Cu/graphene substrate surrounded by copper(Ⅰ)oxide(Cu_(2)O)on a graphene grain boundary over a large area,which is fabricated by the oxidation of the Cu surface via graphene boundary defects by using chemical vapor deposition(CVD).Scanning and transmission electron microscopy results reveal that Cu_(2)O on the graphene boundary can render a preferential reaction with lithium during the first deposition and assist in the uniform deposition of lithium by preventing the agglomeration of lithium clusters during the second deposition.This two-step process is attributed to the degree of selectivity due to the difference in lithium affinity,which allows long-term electrochemical stability and a high rate capability via boundary effects.This study highlights the significance of the boundary effect,which can open new avenues for the formation of a large family of seed structures in lithium-metal batteries. 展开更多
关键词 Cu_(2)O boundary dendrite-free lithium deposition lithium-metal battery lithium spatial control seed boundary effect
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Nano-capillary induced assemble of quantum dots on perovskite grain boundaries for efficient and stable perovskite solar cells
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作者 Miaoyu Lin Jingjing He +10 位作者 Xinyi Liu Qing Li Zhanpeng Wei Yuting Sun Xuesong Leng Mengjiong Chen Zhuhui Xia Yu Peng Qiang Niu Shuang Yang Yu Hou 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第8期595-601,I0014,共8页
In recent years, perovskite solar cells(PSCs) have propelled into the limelight owing to rapid development of efficiency;however, the abundant defects at the perovskite grain boundaries result in unwanted energy loss ... In recent years, perovskite solar cells(PSCs) have propelled into the limelight owing to rapid development of efficiency;however, the abundant defects at the perovskite grain boundaries result in unwanted energy loss and structural degradation. Here, the grain boundaries of perovskite polycrystalline films have been found to act as nanocapillaries for capturing perovskite quantum dots(PQDs), which enable the conformal assemble of PQDs at the top interspace between perovskite grains. The existence of PQDs passivated the surface defects, optimized the interfacial band alignments, and ultimately improved the power conversion efficiency from 19.27% to 22.47% in inverted PSCs. Our findings open up the possibility of selective assembly and structural modulation of the perovskite nanostructures towards efficient and stable PSCs. 展开更多
关键词 Perovskite solar cells Quantum dots CAPILLARITY Grain boundary Passivation
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CONSTANT DISTANCE BOUNDARIES OF THE t-QUASICIRCLE AND THE KOCH SNOWFLAKE CURVE
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作者 魏鑫 文志英 《Acta Mathematica Scientia》 SCIE CSCD 2023年第3期981-993,共13页
LetΓbe a Jordan curve in the complex plane and let Γ_(λ) be the constant distance boundary ofΓ.Vellis and Wu[10]introduced the notion of a(ζ,r_(0))-chordal property which guarantees that,whenλis not too large, ... LetΓbe a Jordan curve in the complex plane and let Γ_(λ) be the constant distance boundary ofΓ.Vellis and Wu[10]introduced the notion of a(ζ,r_(0))-chordal property which guarantees that,whenλis not too large, Γ_(λ) is a Jordan curve whenζ=1/2 and Γ_(λ) is a quasicircle when 0<ζ<1/2.We introduce the(ζ,r_(0),t)-chordal property,which generalizes the(ζ,r_(0))-chordal property,and we show that under the condition thatΓis(ζ,r_(0),√t)-chordal with 0<ζ<r_(0)^(1−√t)/2,there existsε>0 such that Γ_(λ) is a t-quasicircle once Γ_(λ) is a Jordan curve when 0<λ<ε.In the last part of this paper,we provide an example:Γis a kind of Koch snowflake curve which does not have the(ζ,r_(0))-chordal property for any 0<ζ<1/2,however Γ_(λ) is a Jordan curve whenλis small enough.Meanwhile,Γhas the(ζ,r_(0),√t)-chordal property with 0<ζ<r_(0)^(1−√t)/2 for any t∈(0,1/4).As a corollary of our main theorem, Γ_(λ) is a t-quasicircle for all 0<t<1/4 whenλis small enough.This means that our(ζ,r_(0),t)-chordal property is more general and applicable to more complicated curves. 展开更多
关键词 constant distance boundary t-quasicircle Koch snowflake curve
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百脉根类LATERAL ORGAN BOUNDARIES基因的分离及表达方式(英文) 被引量:7
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作者 罗江虹 翁琳 罗达 《植物生理与分子生物学学报》 CAS CSCD 北大核心 2006年第2期202-208,共7页
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 LATERALORGANBOU... 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。 展开更多
关键词 LATERAL ORGAN boundaries 百脉根 LjLOB 复叶 边界
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Behaviors of Lanthanum and Cerium on Grain Boundaries in Carbon Manganese Clean Steel 被引量:18
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作者 林勤 郭锋 朱兴元 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第4期485-489,共5页
The behaviors of La and Ce on gram boundaries in carbon manganese clean steel were investigated by high-reso- lution transmission elecetron microscope (HRTEM), scanning elecetron microscopy(SEM ), energy dispersiv... The behaviors of La and Ce on gram boundaries in carbon manganese clean steel were investigated by high-reso- lution transmission elecetron microscope (HRTEM), scanning elecetron microscopy(SEM ), energy dispersive spectrometer (EDS) and X-ray diffraction(XRD) analysis. The existing forms of rare earths (RE) in clean steel were as follows: dissolved in sohd solution, forming inclusion or second phase containing RE (RE-Fe-P, La-P, Fe-La eutectic and Fe-Ce phase). The dissolved La or Ce segregated at grain boundaries. The segregation of both S and P at gram boundaries was reduced with suitable RE content. The impact toughness of the steel was improved obviously. La and Ce had effecets on purifying molten steel and modifying inclusions in clean steel, whereas with excessive La or Ce, La-Fe-P, La-P and Fe-La eutecetic phase or Ce-Fe-P and Fe-Ce intermetallic compound would form along grain boundaries, causing the impact energy to decrease significantly. 展开更多
关键词 LANTHANUM CERIUM grain boundaries carbon manganese clean steel rare earths
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Seismic wave input method for three-dimensional soil-structure dynamic interaction analysis based on the substructure of artificial boundaries 被引量:12
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作者 Liu Jingbo Tan Hui +2 位作者 Bao Xin Wang Dongyang Li Shutao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第4期747-758,共12页
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... 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. 展开更多
关键词 soil-structure dynamic interaction SEISMIC WAVE INPUT WAVE method EQUIVALENT INPUT SEISMIC loads SUBSTRUCTURE of artifi cial boundaries
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Formation Mechanism of "Drag Depressions" and Irregular Boundaries in Intraplate Deformation 被引量:11
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作者 DENGJun HUANGDinghua +6 位作者 WANGQingfei HOUZengqian LüQingtian YAOLingqing XINHongbo ZHANGQiang WEIYanguang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第1期267-272,共6页
Almost all intraplate caprocks experienced strong deformation during the convergence of microplates, and then disintegrated into many secondary geologic units with the special characters, such as irregular boundaries ... Almost all intraplate caprocks experienced strong deformation during the convergence of microplates, and then disintegrated into many secondary geologic units with the special characters, such as irregular boundaries and particular structural assemblages. In order to understand the formation mechanism of these special phenomena, a rheological experiment on the structural scenery of the Tongling area is carried out. The result shows that the primary regular and uniform boundaries of the Tongling area becomes irregular because of the enclosing and confinement of surrounding geological units in the process of 'compression-shearing-rotation-drag'; simultaneously, two specific 'drag depressions' developed at two opposite corners of the block. The former and the later phenomena can be regarded as a typical regional-scale rheological effect and necessary outcome of intraplate deformation respectively. 展开更多
关键词 intraplate deformation simulation experiment drag depression irregular boundaries Tongling area
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Effect of the frequency of high-angle grain boundaries on the corrosion performance of 5wt%Cr steel in a CO2 aqueous environment 被引量:3
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作者 Hui-bin Wu Tao Wu +3 位作者 Gang Niu Tao Li Rui-yan Sun Yang Gu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第3期315-324,共10页
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 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. 展开更多
关键词 CHROMIUM steel GRAIN boundaries microstructure corrosion performance TEMPERING temperature
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Low-Angle Grain Boundaries in Sublimation Grown 6H-SiC Crystals 被引量:3
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作者 Jiang Shouzhen Li Xianxiang Dong Jie Chen Xiufang Xu Xiangang Hu Xiaobo 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第z1期8-10,共3页
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 i... 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. 展开更多
关键词 LOW-ANGLE GRAIN boundaries SUBLIMATION 6H-SIC RADIAL temperature gradient
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Numerical Simulation of the Protective Effect of Complex Boundaries Toward Shock Waves in a 3D Explosive Field 被引量:3
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作者 吴开腾 宁建国 《Journal of Beijing Institute of Technology》 EI CAS 2003年第1期50-54,共5页
A numerical method is presented that simulates 3D explosive field problems. A code MMIC3D using this method can be used to simulate the propagation and reflected effects of all kinds of rigid boundaries to shock waves... A numerical method is presented that simulates 3D explosive field problems. A code MMIC3D using this method can be used to simulate the propagation and reflected effects of all kinds of rigid boundaries to shock waves produced by an explosive source. These numerical results indicate that the code MMIC3D has the ability in computing cases such as 3D shock waves produced by air explosion, vortex region of the shock wave, the Mach wave, and reflected waves behind rigid boundaries. 展开更多
关键词 explosive field shock wave MMIC3D numerical simulation complex boundaries
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A COMPARISON OF ALTERNATIVE CRITERIA FOR DEFINING FUZZY BOUNDARIES ON FUZZY CATEGORICAL MAPS 被引量:1
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作者 ZHANG Jingxiong Roger P.Kirby 《Geo-Spatial Information Science》 2000年第2期26-34,共9页
This paper provides a brief introduction to the methods for generating fuzzy categorical maps from remotely sensed images (in graphical and digital forms).This is followed by a description of the slicing process for d... This paper provides a brief introduction to the methods for generating fuzzy categorical maps from remotely sensed images (in graphical and digital forms).This is followed by a description of the slicing process for deriving fuzzy boundaries from fuzzy categorical maps,which can be based on the maximum fuzzy membership values,confusion index,or measure of entropy.Results from an empirical test preformed in an Edinburgh suburb show that fuzzy boundaries of land cover can be derived from aerial photographs and satellite images by using the three criteria with small differences,and that slicing based on the maximum fuzzy membership values is the easiest and most straightforward solution.This,in turn,implies the suitability of maintaining both a crisp classification and its underlying certainty map for deriving fuzzy boundaries at different thresholds,which is a flexible and compact management of categorical map data and their uncertainty. 展开更多
关键词 CATEGORICAL mapping objects FIELDS FUZZY CATEGORICAL MAPS FUZZY MEMBERSHIP VALUES (FMVs) FUZZY boundaries
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Stress Field of Non-equilibrium Grain Boundaries in Nano-crystalline Metals 被引量:2
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作者 Chiwei LUNG and Enke TIAN International Centre for Materials Physics, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Hengqiang YE Laboratory of Atomic Imaging of Solids, Institute of Metal Research, Chinese Academy of Sci 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第3期388-388,共1页
Introducing the stress distribution near grain boundaries to improve the dislocation pileup model for the Hall-Petch (H-P) relation, the continuous distribution of dislocations in the pileup could be solved by means o... Introducing the stress distribution near grain boundaries to improve the dislocation pileup model for the Hall-Petch (H-P) relation, the continuous distribution of dislocations in the pileup could be solved by means of Tschebysheff polynomials for the Hubert transformation. An analytical formula of the stress intensity factor for the dislocation pileup is obtained. The reverse H-P relation may be explained by the modified dislocation-pileup-model. 展开更多
关键词 NANO Stress Field of Non-equilibrium Grain boundaries in Nano-crystalline Metals
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Second-Order Adjoint Sensitivity Analysis Methodology for Computing Exactly Response Sensitivities to Uncertain Parameters and Boundaries of Linear Systems: Mathematical Framework 被引量:3
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作者 Dan Gabriel Cacuci 《American Journal of Computational Mathematics》 2020年第3期329-354,共26页
This work presents the “Second-Order Comprehensive Adjoint Sensitivity Analysis Methodology (2<sup>nd</sup>-CASAM)” for the efficient and exact computation of 1<sup>st</sup>- and 2<sup>... This work presents the “Second-Order Comprehensive Adjoint Sensitivity Analysis Methodology (2<sup>nd</sup>-CASAM)” for the efficient and exact computation of 1<sup>st</sup>- and 2<sup>nd</sup>-order response sensitivities to uncertain parameters and domain boundaries of linear systems. The model’s response (<em>i.e.</em>, model result of interest) is a generic nonlinear function of the model’s forward and adjoint state functions, and also depends on the imprecisely known boundaries and model parameters. In the practically important particular case when the response is a scalar-valued functional of the forward and adjoint state functions characterizing a model comprising N parameters, the 2<sup>nd</sup>-CASAM requires a single large-scale computation using the First-Level Adjoint Sensitivity System (1<sup>st</sup>-LASS) for obtaining all of the first-order response sensitivities, and at most N large-scale computations using the Second-Level Adjoint Sensitivity System (2<sup>nd</sup>-LASS) for obtaining exactly all of the second-order response sensitivities. In contradistinction, forward other methods would require (<em>N</em>2/2 + 3 <em>N</em>/2) large-scale computations for obtaining all of the first- and second-order sensitivities. This work also shows that constructing and solving the 2<sup>nd</sup>-LASS requires very little additional effort beyond the construction of the 1<sup>st</sup>-LASS needed for computing the first-order sensitivities. Solving the equations underlying the 1<sup>st</sup>-LASS and 2<sup>nd</sup>-LASS requires the same computational solvers as needed for solving (<em>i.e.</em>, “inverting”) either the forward or the adjoint linear operators underlying the initial model. Therefore, the same computer software and “solvers” used for solving the original system of equations can also be used for solving the 1<sup>st</sup>-LASS and the 2<sup>nd</sup>-LASS. Since neither the 1<sup>st</sup>-LASS nor the 2<sup>nd</sup>-LASS involves any differentials of the operators underlying the original system, the 1<sup>st</sup>-LASS is designated as a “<u>first-level</u>” (as opposed to a “first-order”) adjoint sensitivity system, while the 2<sup>nd</sup>-LASS is designated as a “<u>second-level</u>” (rather than a “second-order”) adjoint sensitivity system. Mixed second-order response sensitivities involving boundary parameters may arise from all source terms of the 2<sup>nd</sup>-LASS that involve the imprecisely known boundary parameters. Notably, the 2<sup>nd</sup>-LASS encompasses an automatic, inherent, and independent “solution verification” mechanism of the correctness and accuracy of the 2nd-level adjoint functions needed for the efficient and exact computation of the second-order sensitivities. 展开更多
关键词 Second-Order Comprehensive Adjoint Sensitivity Analysis Methodology (2nd-CASAM) First-Level Adjoint Sensitivity System (1st-LASS) Second-Level Adjoint Sensitivity System (2nd-LASS) Operator-Type Response Second-Order Sensitivities to Uncertain Model boundaries Second-Order Sensitivities to Uncertain Model Parameters
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Carrier Transport Across Grain Boundaries in Polycrystalline Silicon Thin Film Transistors 被引量:1
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作者 陈勇 ZHANG Shuang +5 位作者 李璋 HUANG Hanhua WANG Wenfeng ZHOU Chao CAO Wanqiang 周郁明 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第1期87-92,共6页
We established a model for investigating polycrystalline silicon(poly-Si) thin film transistors(TFTs).The effect of grain boundaries(GBs) on the transfer characteristics of TFT was analyzed by considering the nu... We established a model for investigating polycrystalline silicon(poly-Si) thin film transistors(TFTs).The effect of grain boundaries(GBs) on the transfer characteristics of TFT was analyzed by considering the number and the width of grain boundaries in the channel region,and the dominant transport mechanism of carrier across grain boundaries was subsequently determined.It is shown that the thermionic emission(TE) is dominant in the subthreshold operating region of TFT regardless of the number and the width of grain boundary.To a poly-Si TFT model with a 1 nm-width grain boundary,in the linear region,thermionic emission is similar to that of tunneling(TU),however,with increasing grain boundary width and number,tunneling becomes dominant. 展开更多
关键词 carrier transport grain boundaries thin film transistors polycrystalline silicon
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Role of Ordering Energy in Formation of Grain Structure and Special Boundaries Spectrum in Ordered Alloys with L12 Superstructure 被引量:1
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作者 O.B.Perevalova (Institute of Strength Physics and Material Science, Russian Academy of Sciences, Siberian Branch pr. Academicheskii, 2/1, 634048, Tomsk, Russia) E. V.Konovalova, N.A.Koneva and E. VKozlov (State University of Architecture and Building, Sol 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第6期585-590,共6页
It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special b... It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special boundaries in coincidence sites of ordered alloys. It was determined that the more energy of special boundaries in ordered alloys, the more energy of complex stacking fault. There is a correlation between the distribution of special boundaries as a function its relative energy and ordering energy: the more ordering energy, the more degree of washed away of distribution. The correlation between average relative energy of special boundaries and ordering energy was detected: the more ordering energy, the more average energy of special boundaries. The reverse dependence between ordering energy and average number of special boundaries in grains limited by boundaries of general type was discovered. 展开更多
关键词 Role of Ordering Energy in Formation of Grain Structure and Special boundaries Spectrum in Ordered Alloys with L12 Superstructure
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Electron Structure of γ/α2 Phase Boundaries in TiAl Based Alloys
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作者 Fantao KONG Ziyong CHEN Yuyong CHEN Jing TIAN Yufeng SI 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第z1期85-87,共3页
The valence electron structure of γ/α2 phase boundaries in lamellar colonies in Ti-47Al-2M (M=Nb, Cr, V) (at. pct) was investigated by empirical electron theory of solid and molecules (EET) and its bond-length-diffe... The valence electron structure of γ/α2 phase boundaries in lamellar colonies in Ti-47Al-2M (M=Nb, Cr, V) (at. pct) was investigated by empirical electron theory of solid and molecules (EET) and its bond-length-difference (BLD) method. On this basis, the boundary condition of electron movement was employed in the improved Thomas-Fermi-Dirac (TFD) theory to decide the continuity of the electron density of the lamellar colonies interface and it is found that of γ/α2 interface is continuous. Furthermore, it is found that adding alloying elements (including Nb, Cr, and V) can improve the electron density (ρ) of γ/α2 interface, decrease Aρ of γ/α2 interface. With the electron structure analysis together with properties analysis,the effect mechanism of alloying elements (Nb, Cr, V) improving mechanical properties was explained. 展开更多
关键词 TIAL based alloy VALENCE ELECTRON structure Phase boundaries SITE OCCUPANCY
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