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3D printing of poly(ethyleneimine)-functionalized Mg-Al mixed metal oxide monoliths for direct air capture of CO_(2)
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作者 Qingyang Shao Zhuozhen Gan +4 位作者 Bingyao Ge Xuyi Liu Chunping Chen Dermot O’Hare Xuancan Zhu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第9期491-500,共10页
Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from t... Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics. 展开更多
关键词 3D printing Mixed metal oxides Amine functionalization Structured adsorbent Direct air capture
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The Precise Order and Singular Directions of Meromorphic Functions 被引量:2
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作者 张学莲 《Journal of Beijing Institute of Technology》 EI CAS 1997年第1期14-18,共5页
The rnemmorphic functions of positive order(both finite positive order and infinite order) are discussed.First,the precise order and type function are given by using the characteristic function.Then some singular dire... The rnemmorphic functions of positive order(both finite positive order and infinite order) are discussed.First,the precise order and type function are given by using the characteristic function.Then some singular directions are defined and their existence is proved. 展开更多
关键词 metamorphic function singular direction precise order
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The Deficiency and Nevanlinna Direction of the Meromorphic Functions *L
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作者 张学莲 《Journal of Beijing Institute of Technology》 EI CAS 1999年第1期15-19,共5页
Aim To study the value distribution of meromorphic functions in angular domains, the deficiency, the deficient value, the Nevanlinna direction and other singular directions. Methods A fundamental inequality of Nevan... Aim To study the value distribution of meromorphic functions in angular domains, the deficiency, the deficient value, the Nevanlinna direction and other singular directions. Methods A fundamental inequality of Nevanlinna characteristic functions in the angular domain was used, which is similar with the Nevanlinna secondary fundamental theorem. Results The deficiency and deficient value of meromorphic functions about an angular domain and a direction were defined. The definition of Nevanlinna direction was improved. Conclusion For a family of meromorphic functions, it is proved that the number of deficient values is at most countable and the sum of deficiencies isnt greater than 2. The existence of the Nevanlinna direction is obtained. The existence of Borel and Julia directions and the relation between them are found. 展开更多
关键词 meromorphic functions DEFICIENCY deficient value Nevanlinna direction sigular direction
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ON NEVANLINNA DIRECTIONS OF ALGEBROID FUNCTIONS 被引量:5
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作者 卢谦 顾永兴 《Acta Mathematica Scientia》 SCIE CSCD 2005年第2期367-375,共9页
In this paper, a notation delta(x)(w) is derived from the counting function N-x(r, w) of branch points of algebriod functions. With this notation, the authors give the definition of the Nevanlinna direction for algebr... In this paper, a notation delta(x)(w) is derived from the counting function N-x(r, w) of branch points of algebriod functions. With this notation, the authors give the definition of the Nevanlinna direction for algebriod functions and discuss its existence in certain condition. By this notation the authors also obtain the numbers of exceptional value of the Julia direction and Borel direction of algebriod functions are not more than 2 + [delta(x) (w)] here [x] implies an maximum integer number which does not exceed x. 展开更多
关键词 Algebriod functions deficient relations Nevanlinna directions
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A proposed directional function and wind-wave directional spectrum 被引量:4
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作者 Wen Shengchang Wu Kejian +1 位作者 Guan Changlong Sun Shicai and Zhang Dacuo (Institute of Physical Oceanography, Ocean University of Oingdao, Oingdao 266003, China) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1995年第2期155-166,共12页
A directional function for frequencies equal to and larger than the peak frequency of a wind-wave frequency spectrum is constructed by fitting the angular spreading based on the analytically derived directional spectr... A directional function for frequencies equal to and larger than the peak frequency of a wind-wave frequency spectrum is constructed by fitting the angular spreading based on the analytically derived directional spectrum of Wen et al. (1993, Journal of Oceanography, 49(2), 131~147, 149~172). For frequencies smaller than the peak frequency, the directional function is obtained by comparing and analyzing existing formulas. The nondimensional wind-wave frequency spectrum of Wen et al. (1994, Progress in Natural Seience, 4(4). 407~427;4 (5), 586~596) has been used together with the directional function just mentioned to obtain the directional spectrum for easier application. 展开更多
关键词 Wind-wave directional function directional spectrum
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THE BOREL DIRECTIONS OF ALGEBROIDAL FUNCTION AND ITS COEFFICIENT FUNCTIONS 被引量:2
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作者 张少华 张晓梅 孙道椿 《Acta Mathematica Scientia》 SCIE CSCD 2014年第2期241-251,共11页
In this article, the relationship between the Borel direction of algebroidal function and its coefficient functions is studied for the first time. To begin with, several theorems of algebroidal functions in unit disk ... In this article, the relationship between the Borel direction of algebroidal function and its coefficient functions is studied for the first time. To begin with, several theorems of algebroidal functions in unit disk are proved. By these theorems, some interesting conclusions are obtained. 展开更多
关键词 Algebroidal function coefficient function Borel direction.
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Decellularized optic nerve functional scaffold transplant facilitates directional axon regeneration and remyelination in the injured white matter of the rat spinal cord 被引量:5
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作者 Yu-Rong Bai Bi-Qin Lai +6 位作者 Wei-Tao Han Jia-Hui Sun Ge Li Ying Ding Xiang Zeng Yuan-Huan Ma Yuan-Shan Zeng 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第11期2276-2283,共8页
Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury.However,achieving good outcome remains difficult.Our previous study showed that porcine decellularize... Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury.However,achieving good outcome remains difficult.Our previous study showed that porcine decellularized optic nerve better mimics the extracellular matrix of the embryonic porcine optic nerve and promotes the directional growth of dorsal root ganglion neurites.However,it has not been reported whether this material promotes axonal regeneration in vivo.In the present study,a porcine decellularized optic nerve was seeded with neurotrophin-3-overexpressing Schwann cells.This functional scaffold promoted the directional growth and remyelination of regenerating axons.In vitro,the porcine decellularized optic nerve contained many straight,longitudinal channels with a uniform distribution,and microscopic pores were present in the channel wall.The spatial micro topological structure and extracellular matrix were conducive to the adhesion,survival and migration of neural stem cells.The scaffold promoted the directional growth of dorsal root ganglion neurites,and showed strong potential for myelin regeneration.Furthermore,we transplanted the porcine decellularized optic nerve containing neurotrophin-3-overexpressing Schwann cells in a rat model of T10 spinal cord defect in vivo.Four weeks later,the regenerating axons grew straight,the myelin sheath in the injured/transplanted area recovered its structure,and simultaneously,the number of inflammatory cells and the expression of chondroitin sulfate proteoglycans were reduced.Together,these findings suggest that porcine decellularized optic nerve loaded with Schwann cells overexpressing neurotrophin-3 promotes the directional growth of regenerating spinal cord axons as well as myelin regeneration.All procedures involving animals were conducted in accordance with the ethical standards of the Institutional Animal Care and Use Committee of Sun Yat-sen University(approval No.SYSU-IACUC-2019-B034)on February 28,2019. 展开更多
关键词 axonal regeneration decellularized optic nerve directional regeneration functional scaffold microenvironment NEUROTROPHIN-3 optic nerve REMYELINATION Schwann cells tissue engineering white matter injury
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Three-dimensional free vibration analysis of multi-directional functionally graded piezoelectric annular plates on elastic foundations via state space based differential quadrature method 被引量:3
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作者 M.H.YAS N.MOLOUDI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第4期439-464,共26页
The three-dimensional free vibration analysis of a multi-directional func- tionally graded piezoelectric (FGP) annular plate resting on two parameter (Pasternak) elastic foundations is investigated under different... The three-dimensional free vibration analysis of a multi-directional func- tionally graded piezoelectric (FGP) annular plate resting on two parameter (Pasternak) elastic foundations is investigated under different boundary conditions. The material properties are assumed to vary continuously along the radial and thickness directions and have exponent-law distribution. A semi-analytical approach named the state space based differential quadrature method (SSDQM) is used to provide an analytical solution along the thickness using the state space method (SSM) and an approximate solution along the radial direction using the one-dimensional differential quadrature method (DQM). The influence of the Winkler and shear stiffness of the foundation~ the material property graded variations, and the circumferential wave number on the nomdimensional natural frequency of multi-directional FGP annular plates is studied. 展开更多
关键词 multi-directional functionally graded PIEZOELECTRIC annular plate freevibration
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ON THE NEVANLINNA DIRECTION OF ALGEBROID FUNCTIONS
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作者 张洪申 孙道椿 《Acta Mathematica Scientia》 SCIE CSCD 2012年第4期1441-1448,共8页
In this paper, we prove that for an algebroid function w(z), the singular direction argz = φ0, satisfying that for arbitrary ε(0 〈 ε 〈 2/π) and any given α ∈ C^^,limr→+∞ log τ/n(τ,φ0-ε,φ0+ε,w=a... In this paper, we prove that for an algebroid function w(z), the singular direction argz = φ0, satisfying that for arbitrary ε(0 〈 ε 〈 2/π) and any given α ∈ C^^,limr→+∞ log τ/n(τ,φ0-ε,φ0+ε,w=a)=+∞ holds with at most; 2v possible exceptional values of a, is the Ncvanlinna direction of w(z). 展开更多
关键词 algebroid function Nevanlinna direction algebroid function Nevanlinna direction
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AXISYMMETRIC BENDING OF TWO-DIRECTIONAL FUNCTIONALLY GRADED CIRCULAR AND ANNULAR PLATES 被引量:6
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作者 Guojun Nie Zheng Zhong 《Acta Mechanica Solida Sinica》 SCIE EI 2007年第4期289-295,共7页
Assuming the material properties varying with an exponential law both in the thick- ness and radial directions, axisymmetric bending of two-directional functionally graded circular and annular plates is studied using ... Assuming the material properties varying with an exponential law both in the thick- ness and radial directions, axisymmetric bending of two-directional functionally graded circular and annular plates is studied using the semi-analytical numerical method in this paper. The deflections and stresses of the plates are presented. Numerical results show the well accuracy and convergence of the method. Compared with the finite element method, the semi-analytical nu- merical method is with great advantage in the computational efficiency. Moreover, study on ax- isymmetric bending of two-directional functionally graded annular plate shows that such plates have better performance than those made of isotropic homogeneous materials or one-directional functionally graded materials. Two-directional functionally graded material is a potential alternative to the one-directional functionally graded material. And the integrated design of materials and structures can really be achieved in two-directional functionally graded materials. 展开更多
关键词 two-directional functionally graded materials circular and annular plates axisym-metric bending semi-analytical numerical method integrated design
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On Singular Directions of Entire and Meromorphic Functions
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作者 常建明 宋国栋 任福尧 《Northeastern Mathematical Journal》 CSCD 2000年第4期379-382,共4页
关键词 entire and meromorphic function Martys direction GROWTH
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Direction-dependent functions of physical properties for crystals and polycrystals
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作者 Mojia Huang Mengcheng Chen Tenglong Zheng 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2009年第5期639-649,共11页
Some physical properties of crystals differ in direction n because crystal lattices are often anisotropic. A polycrystal is an aggregate of numerous tiny crystallites. Unless the polycrystal is an isotropic aggregate ... Some physical properties of crystals differ in direction n because crystal lattices are often anisotropic. A polycrystal is an aggregate of numerous tiny crystallites. Unless the polycrystal is an isotropic aggregate of crystallites, the physical properties of the polycrystal vary with n. The direction-dependent functions (DDF) for crystals and polycrystals are introduced to describe the variations of the physical properties in direction n. Until now there are few papers dealing systematically with relations between the DDF and the crystalline orientation distribution. Herein we give general expressions of the DDF for crystals and polycrystals. We discuss the applications of the DDF in describing the physical properties of crystals and polycrystals. 展开更多
关键词 Direction-dependent function Orientation distribution function Physical properties of crystals and polycrystals
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Wideband direction-of-arrival estimation based on cubic spline function
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作者 Hongqi Yu David Day-Uei Li +2 位作者 Kun Zhang Jietao Diao Haijun Liu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第4期688-693,共6页
A new direction-of-arrival (DOA) estimation algorithm for wideband sources is introduced, The new method obtains the output of the virtual arrays in the signal bandwidth using cubic spline function interpolation tec... A new direction-of-arrival (DOA) estimation algorithm for wideband sources is introduced, The new method obtains the output of the virtual arrays in the signal bandwidth using cubic spline function interpolation techniques. The narrowband high- resolution algorithm is then used to get the DOA estimation. This technique does not require any preliminary knowledge of DOA angles. Simulation results demonstrate the effectiveness of the method. 展开更多
关键词 array signal processing wideband sources cubicspline function direction-of-arrival (DOA) estimation.
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Fully Distributed Learning for Deep Random Vector Functional-Link Networks
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作者 Huada Zhu Wu Ai 《Journal of Applied Mathematics and Physics》 2024年第4期1247-1262,共16页
In the contemporary era, the proliferation of information technology has led to an unprecedented surge in data generation, with this data being dispersed across a multitude of mobile devices. Facing these situations a... In the contemporary era, the proliferation of information technology has led to an unprecedented surge in data generation, with this data being dispersed across a multitude of mobile devices. Facing these situations and the training of deep learning model that needs great computing power support, the distributed algorithm that can carry out multi-party joint modeling has attracted everyone’s attention. The distributed training mode relieves the huge pressure of centralized model on computer computing power and communication. However, most distributed algorithms currently work in a master-slave mode, often including a central server for coordination, which to some extent will cause communication pressure, data leakage, privacy violations and other issues. To solve these problems, a decentralized fully distributed algorithm based on deep random weight neural network is proposed. The algorithm decomposes the original objective function into several sub-problems under consistency constraints, combines the decentralized average consensus (DAC) and alternating direction method of multipliers (ADMM), and achieves the goal of joint modeling and training through local calculation and communication of each node. Finally, we compare the proposed decentralized algorithm with several centralized deep neural networks with random weights, and experimental results demonstrate the effectiveness of the proposed algorithm. 展开更多
关键词 Distributed Optimization Deep Neural Network Random Vector Functional-Link (RVFL) Network Alternating Direction Method of Multipliers (ADMM)
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Fingerprint Directional Image Partitioning Based on Genetic Algorithm
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作者 张朝鸣 刘云超 《Advances in Manufacturing》 SCIE CAS 2000年第S1期98-103,共6页
In this work, we introduce a method of fingerprint directional image partitioning based on GA. According to the fingerprint topology, A set of dynamic partition masks and a cost estimating function are designed to gui... In this work, we introduce a method of fingerprint directional image partitioning based on GA. According to the fingerprint topology, A set of dynamic partition masks and a cost estimating function are designed to guide the partitioning procedure. Finding best fitted mask application is converted to an functional optimizing problem, and we give out a GA solution to the problem. At last, we discuss the application of the proposed method in Fingerprint Classification. 展开更多
关键词 fingerprint classification directional image partitioning dynamic mask cost estimating function genetic algorithm (GA)
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DIRECT AND ADAPTIVE SLICING ON CAD MODEL OF IDEAL FUNCTIONAL MATERIAL COMPONENTS (IFMC) 被引量:3
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作者 XuDaoming JiaZhenyuan GuoDongming 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2005年第1期139-144,共6页
A brand new direct and adaptive slicing approach is proposed, which canapparently improve the part accuracy and reduce the building time. At least two stages are includedin this operation: getting the crossing contour... A brand new direct and adaptive slicing approach is proposed, which canapparently improve the part accuracy and reduce the building time. At least two stages are includedin this operation: getting the crossing contour of the cutting plane with the solid part anddetermining the layer thickness. Apart from usual SPI algorithm, slicing of the solid model has itsspecial requirements. Enabling the contour line segments of the cross-section as long as possible isone of them, which is for improving manufacturing efficiency and is reached by adaptively adjustingthe step direction and the step size at every crossing point to obtain optimized secant height. Thelayer thickness determination can be divided into two phases: the geometry-based thicknessestimation and the material-based thickness verifying. During the former phase, the geometrytolerance is divided into two parts: a variety of curves are approximated by a circular arc, whichintroduces the first part, and the deviation error between the contour line in LM process and thecircular arc generates the second part. The latter phase is mainly verifying the layer thicknessestimated in the former stage and determining a new one if necessary. In addition, an example usingthis slicing algorithm is also illustrated. 展开更多
关键词 Rapid prototyping Ideal functional material components Direct and adaptiveslicing Surface/plane intersection MARCHING
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LIMITING DIRECTIONS OF JULIA SETS OF ENTIRE SOLUTIONS TO COMPLEX DIFFERENTIAL EQUATIONS 被引量:2
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作者 王珺 陈宗煊 《Acta Mathematica Scientia》 SCIE CSCD 2017年第1期97-107,共11页
In this paper,we mainly investigate the dynamical properties of entire solutions of complex differential equations.With some conditions on coefficients,we prove that the set of common limiting directions of Julia sets... In this paper,we mainly investigate the dynamical properties of entire solutions of complex differential equations.With some conditions on coefficients,we prove that the set of common limiting directions of Julia sets of solutions,their derivatives and their primitives must have a definite range of measure. 展开更多
关键词 limiting direction Julia set entire function linear differential equation defi-ciency
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LIMITING DIRECTION AND BAKER WANDERING DOMAIN OF ENTIRE SOLUTIONS OF DIFFERENTIAL EQUATIONS 被引量:2
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作者 王珺 陈宗煊 《Acta Mathematica Scientia》 SCIE CSCD 2016年第5期1331-1342,共12页
In this paper, we mainly investigate entire solutions of complex differential equations with coefficients involving exponential functions, and obtain the dynamical properties of the solutions, their derivatives and pr... In this paper, we mainly investigate entire solutions of complex differential equations with coefficients involving exponential functions, and obtain the dynamical properties of the solutions, their derivatives and primitives. With some conditions on coefficients, for the solutions, their derivatives and their primitives, we consider the common limiting directions of Julia set and the existence of Baker wandering domain. 展开更多
关键词 limiting direction Baker wandering domain entire function linear differential equation
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Two-Order Approximate and Large Stepsize Numerical Direction Based on the Quadratic Hypothesis and Fitting Method 被引量:3
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作者 Xiaoli Yin Chunming Li Yuan Zhang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第3期901-909,共9页
Many effective optimization algorithms require partial derivatives of objective functions, while some optimization problems' objective functions have no derivatives. According to former research studies, some sear... Many effective optimization algorithms require partial derivatives of objective functions, while some optimization problems' objective functions have no derivatives. According to former research studies, some search directions are obtained using the quadratic hypothesis of objective functions. Based on derivatives, quadratic function assumptions, and directional derivatives, the computational formulas of numerical first-order partial derivatives, second-order partial derivatives, and numerical second-order mixed partial derivatives were constructed. Based on the coordinate transformation relation, a set of orthogonal vectors in the fixed coordinate system was established according to the optimization direction. A numerical algorithm was proposed, taking the second order approximation direction as an example. A large stepsize numerical algorithm based on coordinate transformation was proposed. Several algorithms were validated by an unconstrained optimization of the two-dimensional Rosenbrock objective function. The numerical second order approximation direction with the numerical mixed partial derivatives showed good results. Its calculated amount is 0.2843% of that of without second-order mixed partial derivative. In the process of rotating the local coordinate system 360°, because the objective function is more complex than the quadratic function, if the numerical direction derivative is used instead of the analytic partial derivative, the optimization direction varies with a range of 103.05°. Because theoretical error is in the numerical negative gradient direction, the calculation with the coordinate transformation is 94.71% less than the calculation without coordinate transformation. If there is no theoretical error in the numerical negative gradient direction or in the large-stepsize numerical optimization algorithm based on the coordinate transformation, the sawtooth phenomenon occurs. When each numerical mixed partial derivative takes more than one point, the optimization results cannot be improved. The numerical direction based on the quadratic hypothesis only requires the objective function to be obtained, but does not require derivability and does not take into account truncation error and rounding error. Thus, the application scopes of many optimization methods are extended. 展开更多
关键词 Directional DERIVATIVE NUMERICAL DIFFERENTIAL optimization method QUADRATIC function HYPOTHESIS
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BOREL'S DIRECTIONS AND SHARED VALUES 被引量:1
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作者 张庆彩 《Acta Mathematica Scientia》 SCIE CSCD 2013年第2期471-483,共13页
In this article, we study the problems of Borel's directions of meromorphic func- tions concerning shared values and prove that if two meromorphie functions of infinite order share three distinct values, their Borel... In this article, we study the problems of Borel's directions of meromorphic func- tions concerning shared values and prove that if two meromorphie functions of infinite order share three distinct values, their Borel's directions are same. 展开更多
关键词 Meromorphic function Borel's direction shared value angular domain
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