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Generalized functional model of maximum and minimum detectable deformation gradient for PALSAR interferometry 被引量:2
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作者 王琪洁 李志伟 +4 位作者 杜亚男 谢荣安 张杏清 蒋弥 朱建军 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第3期824-832,共9页
Empirical functional models for the maximum and minimum detectable deformation gradient of PALSAR interferometry were established based on coherence and discrete look numbers. Then, a least square regression method wa... Empirical functional models for the maximum and minimum detectable deformation gradient of PALSAR interferometry were established based on coherence and discrete look numbers. Then, a least square regression method was used to fit the model coefficients and thus obtain the generalized functional models for both coherence and look numbers. The experimental results with ALOS PALSAR data of Wenchuan earthquake of China show that the new model works well for judging whether the deformation gradient can be detected by the D-InSAR technology or not. The results can help researchers to choose PALSAR data and to configure processing parameters, and also benefit the interpretation of the measured surface deformation. 展开更多
关键词 PALSAR D-INSAR deformation gradient COHERENCE multilook number functional model
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Two kinds of generalized gradient representations for holonomic mechanical systems 被引量:5
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作者 梅凤翔 吴惠彬 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第1期653-656,共4页
Two kinds of generalized gradient systems are proposed and the characteristics of the two systems are studied. The conditions under which a holonomic mechanical system can be considered as one of the two generalized g... Two kinds of generalized gradient systems are proposed and the characteristics of the two systems are studied. The conditions under which a holonomic mechanical system can be considered as one of the two generalized gradient systems are obtained. The characteristics of the generalized gradient systems can be used to study the stability of the holonomic system. Some examples are given to illustrate the application of the results. 展开更多
关键词 holonomic mechanical system generalized gradient system Lyapunov function stability
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Skew-gradient representation of generalized Birkhoffian system 被引量:7
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作者 梅凤翔 吴惠彬 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第10期312-314,共3页
The skew-gradient representation of a generalized Birkhoffian system is studied. A condition under which the generalized Birkhoffian system can be considered as a skew-gradient system is obtained. The properties of th... The skew-gradient representation of a generalized Birkhoffian system is studied. A condition under which the generalized Birkhoffian system can be considered as a skew-gradient system is obtained. The properties of the skew-gradient system are used to study the properties, especially the stability, of the generalized Birkhoffian system. Some examples are given to illustrate the application of the result. 展开更多
关键词 generalized Birkhoffian system skew-gradient system Lyapunov function STABILITY
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Combined Gradient Representations for Generalized Birkhoffian Systems in Event Space and Its Stability Analysis 被引量:2
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作者 WANG Jiahang BAO Siyuan 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第6期967-974,共8页
The combined gradient representations for generalized Birkhoffian systems in event space are studied.Firstly,the definitions of six kinds of combined gradient systems and corresponding differential equations are given... The combined gradient representations for generalized Birkhoffian systems in event space are studied.Firstly,the definitions of six kinds of combined gradient systems and corresponding differential equations are given.Secondly,the conditions under which generalized Birkhoffian systems become combined gradient systems are obtained. Finally,the characteristics of combined gradient systems are used to study the stability of generalized Birkhoffian systems in event space. Seven examples are given to illustrate the results. 展开更多
关键词 generalized Birkhoffian system event space combined gradient systems stability
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Active contours with normally generalized gradient vector flow external force 被引量:1
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作者 赵恒博 刘利雄 +2 位作者 张麒 姚宇华 刘宝 《Journal of Beijing Institute of Technology》 EI CAS 2012年第2期240-245,共6页
Gradient vector flow (GVF) is an effective external force for active contours, but its iso- tropic nature handicaps its performance. The recently proposed gradient vector flow in the normal direction (NGVF) is ani... Gradient vector flow (GVF) is an effective external force for active contours, but its iso- tropic nature handicaps its performance. The recently proposed gradient vector flow in the normal direction (NGVF) is anisotropic since it only keeps the diffusion along the normal direction of the isophotes; however, it has difficulties forcing a snake into long, thin boundary indentations. In this paper, a novel external force for active contours called normally generalized gradient vector flow (NGGVF) is proposed, which generalizes the NGVF formulation to include two spatially varying weighting functions. Consequently, the proposed NGGVF snake is anisotropic and would improve ac- tive contour convergence into long, thin boundary indentations while maintaining other desirable properties of the NGVF snake, such as enlarged capture range, initialization insensitivity and good convergence at concavities. The advantages on synthetic and real images are demonstrated. 展开更多
关键词 gradient vector flow active contour normal gradient vector flow normally generalizedgradient vector flow
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A New Conjugate Gradient Projection Method for Solving Stochastic Generalized Linear Complementarity Problems 被引量:2
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作者 Zhimin Liu Shouqiang Du Ruiying Wang 《Journal of Applied Mathematics and Physics》 2016年第6期1024-1031,共8页
In this paper, a class of the stochastic generalized linear complementarity problems with finitely many elements is proposed for the first time. Based on the Fischer-Burmeister function, a new conjugate gradient proje... In this paper, a class of the stochastic generalized linear complementarity problems with finitely many elements is proposed for the first time. Based on the Fischer-Burmeister function, a new conjugate gradient projection method is given for solving the stochastic generalized linear complementarity problems. The global convergence of the conjugate gradient projection method is proved and the related numerical results are also reported. 展开更多
关键词 Stochastic generalized Linear Complementarity Problems Fischer-Burmeister Function Conjugate gradient Projection Method Global Convergence
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Assignment of terahertz vibrational modes of L-glutamine using density functional theory within generalized-gradient approximation 被引量:8
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作者 张寒 张朝晖 +3 位作者 赵小燕 张天尧 燕芳 申江 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第7期211-218,共8页
The crystal structure of L-glutamine is stabilized by a three-dimensional network of intermolecular hydrogen bonds.We utilize plane-wave density functional theory lattice-dynamics calculations within the generalized-g... The crystal structure of L-glutamine is stabilized by a three-dimensional network of intermolecular hydrogen bonds.We utilize plane-wave density functional theory lattice-dynamics calculations within the generalized-gradient approximation(GGA), Perdew–Burke–Ernzerhof(PBE), PBE for solids(PBEsol), PBE with Wu–Cohen exchange(WC), and dispersion-corrected PBE, to investigate the effect of these intermolecular contacts on the absorption spectra of glutamine in the terahertz frequency range. Among these calculations, the solid-state simulated results obtained using the WC method exhibit a good agreement with the measured absorption spectra, and the absorption features are assigned with the help of WC. This indicates that the vibrational modes of glutamine were related to the combination of intramolecular and intermolecular motions, the intramolecular modes were dominated by rocking or torsion involving functional groups; the intermolecular modes mainly result from the translational motions of individual molecules, and the rocking of the hydrogenbonded functional groups. 展开更多
关键词 terahertz vibrational modes amino acid plane-wave density functional theory generalized-gradient approximation
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Electronic and Optical Properties of TiS2 Determined from Generalized Gradient Approximation Study
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作者 Hamza El-Kouch Larbi El Farh +1 位作者 Jamal Sayah Allal Challioui 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期96-99,共4页
The electronic and optical properties of TiS2 are studied of density functional theory. A linearized and augmented by using an ab-initio calculation within the frame plane wave basis set with the generalized gradient ... The electronic and optical properties of TiS2 are studied of density functional theory. A linearized and augmented by using an ab-initio calculation within the frame plane wave basis set with the generalized gradient approximation as proposed by Perdew et al. is used for the energy exchange-correlation determination. The results show a metallic character of TiS2, and the plots of total and partial densities of states of TiS2 show the metallic character of the bonds and a strong hybridization between the states d of Ti and p of S below the Fermi energy. The optical properties of the material such as real and imaginary parts of dielectric constant (ε(w) = ε1(w) + iε2(w)), refractive index n(w), optical reflectivity R(w), for E / /x and E / /z are performed for the energy range of 0-.14 eV. 展开更多
关键词 TI ab Electronic and Optical Properties of TiS2 Determined from generalized gradient Approximation Study
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Spectral Gradient Algorithm Based on the Generalized Fiser-Burmeister Function for Sparse Solutions of LCPS
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作者 Chang Gao Zhensheng Yu Feiran Wang 《Open Journal of Statistics》 2015年第6期543-551,共9页
This paper considers the computation of sparse solutions of the linear complementarity problems LCP(q, M). Mathematically, the underlying model is NP-hard in general. Thus an lp(0 p < 1) regularized minimization mo... This paper considers the computation of sparse solutions of the linear complementarity problems LCP(q, M). Mathematically, the underlying model is NP-hard in general. Thus an lp(0 p < 1) regularized minimization model is proposed for relaxation. We establish the equivalent unconstrained minimization reformation of the NCP-function. Based on the generalized Fiser-Burmeister function, a sequential smoothing spectral gradient method is proposed to solve the equivalent problem. Numerical results are given to show the efficiency of the proposed method. 展开更多
关键词 Linear Complementarity Problem SPARSE Solution SPECTRAL gradient generalized Fischer-Burmeister
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GENERALIZED CONJUGATE-GRADIENT ALGORITHM AND ITS APPLICATIONS TO SEISMIC TRACE INVERSION
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作者 Zhusheng, Zhou Jishan, He Heqing, Zhao 《中国有色金属学会会刊:英文版》 EI CSCD 1999年第1期183-189,共7页
1INTRODUCTIONCurently,seismictraceinversionhasalreadybeenanimportantworkinseismicdataprocessingformeticulous... 1INTRODUCTIONCurently,seismictraceinversionhasalreadybeenanimportantworkinseismicdataprocessingformeticulousoilgasexplorati... 展开更多
关键词 SEISMIC TRACE INVERSION CONJUGATE gradient ALGORITHM accuracy stability operation speed
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Computation of waves scattered by inhomogeneous velocity gradient using generalized Born approximation
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作者 LIU Bo SUN Jianguo MENG Xiangyu 《Global Geology》 2020年第1期24-31,共8页
The generalized Born approximation is an approximation method that represents the scattering term by the error between the exact Green's function and the approximate Green's function,mainly for the gradient sc... The generalized Born approximation is an approximation method that represents the scattering term by the error between the exact Green's function and the approximate Green's function,mainly for the gradient scattering problem.However,so far,the research on the generalized Born approximation has only stayed in theory,and its implementation techniques are rarely reported.In order to fill this gap,the basic theory of generalized Born approximation is reviewed,and the implementation method of generalized Born approximation is discussed in this paper.In particular,the problem of calculating boundary effect elimination is discussed in detail.Finally,through model trial calculation,the calculation of gradient scattering,by comparing Born approximation and finite difference method,shows that using the generalized Born approximation to calculate gradient scattering achieves higher computational accuracy. 展开更多
关键词 generalized Born approximation gradient scattering implementation technology numerical simulation
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Application of the Generalized Reduced Gradient Method in Mechanical Optimization Design
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作者 LI Hong-wei 《International Journal of Plant Engineering and Management》 2010年第2期107-110,116,共5页
This paper presents the generalized reduced gradient method (GRG) and its realization forms. The application example of GRG in the optimization design of a single-stage cylindrical gear reducer is introduced. The al... This paper presents the generalized reduced gradient method (GRG) and its realization forms. The application example of GRG in the optimization design of a single-stage cylindrical gear reducer is introduced. The algo- rithm of the GRG method is realized in Vissim software. Based on the mathematical model of the single-stage cylin- drical gear reducer, the simulation structure of the optimization design was achieved. The experiment results show that the GRG method has fewer iterations and higher precision. The GRG method is very suitable for solving mechanical optimization design. 展开更多
关键词 generalized reduced gradient method optimization design vissim software SIMULATION
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New applications of a generalized Hooke's law for second gradient materials
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作者 K.Enakoutsa 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2015年第3期129-133,共5页
We provide analytical solutions to the problems of a circular bending of a beam in plane strain and the torsion of a non-circular cross-section beam, the beams obeying a second-gradient elasticity law proposed by the ... We provide analytical solutions to the problems of a circular bending of a beam in plane strain and the torsion of a non-circular cross-section beam, the beams obeying a second-gradient elasticity law proposed by the author, following a previous suggestion of delrlsola et al. (2009). The motivation was to find benchmark analytical solutions that can serve to grasp the physical foundations of second gradient elasticity laws for heterogeneous materials. The analytical solution of the circular beam problem presents the additional advantage to establish some nice properties on the unknown second gradient elastic moduli introduced by Enakoutsa (2014) model and the classical elasticity constants for both incompressible and compressible heterogeneous elastic materials. A framework to find the elastic moduli of the new model is also proposed. 展开更多
关键词 Second gradient theory Beam Analytical solution
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A Phenomenological Gradient Approach to Generalized Constitutive Equations for Isotropic Fluids
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作者 Alejandro Salcido 《Journal of Applied Mathematics and Physics》 2018年第7期1494-1506,共13页
An extension of the linear irreversible thermodynamics is proposed through the inclusion of the first gradients of velocity and of the classical local state parameters as additional independent variables in the fundam... An extension of the linear irreversible thermodynamics is proposed through the inclusion of the first gradients of velocity and of the classical local state parameters as additional independent variables in the fundamental energy state equation of a fluid system. We show that consistency of this hypothesis with the energy balance equation leads to generalized nonlinear constitutive equations, which we discuss in terms of an isotropic non-Newtonian viscous fluid. 展开更多
关键词 NON-LOCAL Thermodynamics Non-Newtonian VISCOUS FLUIDS generalized CONSTITUTIVE Equations
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ONLINE REGULARIZED GENERALIZED GRADIENT CLASSIFICATION ALGORITHMS
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作者 Leilei Zhang Baohui Sheng Jianli Wang 《Analysis in Theory and Applications》 2010年第3期278-300,共23页
This paper considers online classification learning algorithms for regularized classification schemes with generalized gradient. A novel capacity independent approach is presented. It verifies the strong convergence o... This paper considers online classification learning algorithms for regularized classification schemes with generalized gradient. A novel capacity independent approach is presented. It verifies the strong convergence of sizes and yields satisfactory convergence rates for polynomially decaying step sizes. Compared with the gradient schemes, this al- gorithm needs only less additional assumptions on the loss function and derives a stronger result with respect to the choice of step sizes and the regularization parameters. 展开更多
关键词 online learning algorithm reproducing kernel Hilbert space generalized gra-dient Clarke's directional derivative learning rate
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Nonmonotonic Trust Region Algorithm via the Conjugate Gradient Path for Unconstrained Generalized Geometric Programming
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作者 DANG Ya-zheng JING Shu-jie LI Yu 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第2期285-289,共5页
In this paper,on the basis of making full use of the characteristics of unconstrained generalized geometric programming(GGP),we establish a nonmonotonic trust region algorithm via the conjugate path for solving unco... In this paper,on the basis of making full use of the characteristics of unconstrained generalized geometric programming(GGP),we establish a nonmonotonic trust region algorithm via the conjugate path for solving unconstrained GGP problem.A new type of condensation problem is presented,then a particular conjugate path is constructed for the problem,along which we get the approximate solution of the problem by nonmonotonic trust region algorithm,and further prove that the algorithm has global convergence and quadratic convergence properties. 展开更多
关键词 generalized geometric programming condensation conjugate path trust region
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A Modified PRP-HS Hybrid Conjugate Gradient Algorithm for Solving Unconstrained Optimization Problems 被引量:1
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作者 LI Xiangli WANG Zhiling LI Binglan 《应用数学》 北大核心 2025年第2期553-564,共12页
In this paper,we propose a three-term conjugate gradient method for solving unconstrained optimization problems based on the Hestenes-Stiefel(HS)conjugate gradient method and Polak-Ribiere-Polyak(PRP)conjugate gradien... In this paper,we propose a three-term conjugate gradient method for solving unconstrained optimization problems based on the Hestenes-Stiefel(HS)conjugate gradient method and Polak-Ribiere-Polyak(PRP)conjugate gradient method.Under the condition of standard Wolfe line search,the proposed search direction is the descent direction.For general nonlinear functions,the method is globally convergent.Finally,numerical results show that the proposed method is efficient. 展开更多
关键词 Conjugate gradient method Unconstrained optimization Sufficient descent condition Global convergence
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Absorption-Reflection-Transmission Power Coefficient Guiding Gradient Distribution of Magnetic MXene in Layered Composites for Electromagnetic Wave Absorption 被引量:3
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作者 Yang Zhou Wen Zhang +7 位作者 Dong Pan Zhaoyang Li Bing Zhou Ming Huang Liwei Mi Chuntai Liu Yuezhan Feng Changyu Shen 《Nano-Micro Letters》 2025年第6期466-481,共16页
The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electrom... The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electromagnetic component regulation,layered arrangement structure,and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss.On the microscale,the incorporation of magnetic Ni nanoparticles into MXene nanosheets(Ni@MXene)endows suitable intrinsic permittivity and permeability.On the macroscale,the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves,inducing multiple reflection/scattering effects.On this basis,according to the analysis of absorption,reflection,and transmission(A-R-T)power coefficients of layered composites,the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer,electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer.Consequently,the layered gradient composite(LG5-10-15)achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RL_(min) of-68.67 dB at 9.85 GHz in 2.05 mm,which is 199.0%,12.6%,and 50.6%higher than non-layered,layered and layered descending gradient composites,respectively.Therefore,this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials. 展开更多
关键词 Magnetic MXene Layered and gradient structure Power coefficient Electromagnetic wave absorption
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CNN-ALSTM Soft-Sensing Model for Resistivity Gradient in CZ Monocrystalline Silicon Wafers 被引量:1
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作者 Zhiheng Zhang Zengguo Tian 《Instrumentation》 2025年第2期71-79,共9页
This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Me... This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth. 展开更多
关键词 CZ monocrystalline silicon soft-sensing model CNN-ALSTM resistivity gradient
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Advances in the Development of Gradient Scaffolds Made of Nano‑Micromaterials for Musculoskeletal Tissue Regeneration
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作者 Lei Fang Xiaoqi Lin +5 位作者 Ruian Xu Lu Liu Yu Zhang Feng Tian Jiao Jiao Li Jiajia Xue 《Nano-Micro Letters》 SCIE EI CAS 2025年第3期455-500,共46页
The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.T... The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries. 展开更多
关键词 gradient scaffolds Musculoskeletal tissues Advanced manufacturing BIOMATERIALS Tissue regeneration
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