为了研究变压器直流偏磁下的铁心损耗,文章以某一核电站500 k V主变压器为例,在二维有限元瞬态场A–φ算法基础下构造了直流偏磁下的变压器二维仿真损耗模型。在仿真中,偏磁直流量从0 A增加至30 A,可得到变压器铁心的损耗分布。结果分...为了研究变压器直流偏磁下的铁心损耗,文章以某一核电站500 k V主变压器为例,在二维有限元瞬态场A–φ算法基础下构造了直流偏磁下的变压器二维仿真损耗模型。在仿真中,偏磁直流量从0 A增加至30 A,可得到变压器铁心的损耗分布。结果分析可表明:随着偏磁直流量的增加,励磁电流会产生畸变和较大的偶次谐波,并导致铁心局部损耗增大,其中:铁心主柱与上、下铁轭交接区域的损耗值受到直流偏磁的影响最大,铁心水平路径的损耗值相较于垂直路径受直流偏磁的影响较大。展开更多
In this paper,various aspects of the 2D and 3D nonlinear liquid sloshing problems in vertically excited containers have been studied numerically along with the help of a modified-transformation.Based on this new numer...In this paper,various aspects of the 2D and 3D nonlinear liquid sloshing problems in vertically excited containers have been studied numerically along with the help of a modified-transformation.Based on this new numerical algorithm,a numerical study on a regularly and randomly excited container in vertical direction was conducted utilizing four different cases： The first case was performed utilizing a 2D container with regular excitations.The next case examined a regularly excited 3D container with two different initial conditions for the liquid free surface,and finally,3D container with random excitation in the vertical direction.A grid independence study was performed along with a series of validation tests.An iteration error estimation method was used to stop the iterative solver（used for solving the discretized governing equations in the computational domain） upon reaching steady state of results at each time step.In the present case,this method was found to produce quite accurate results and to be more time efficient as compared to other conventional stopping procedures for iterative solvers.The results were validated with benchmark results.The wave elevation time history,phase plane diagram and surface plots represent the wave nonlinearity during its motion.展开更多
Abstract： The shortest path problem in a network G is to find shortest paths between some specified source vertices and terminal vertices when the lengths of edges are given. The structure of the optimal solutions se...Abstract： The shortest path problem in a network G is to find shortest paths between some specified source vertices and terminal vertices when the lengths of edges are given. The structure of the optimal solutions set on the shortest paths is studied in this paper. First, the conditions of having unique shortest path between two distinguished vertices 8 and t in a network G are discussed; Second, the structural properties of 2-transformation ^-G graph G on the shortest-paths for G are presented heavily.展开更多
A total synthesis of (E,E)-3,7-dimethyl-2,6-decadiene-1,10-diol, using 1,3-transformation of 2, 3-epoxy alcohol and Claisen rearrangement of allyl vinyl ether as key steps, is described.
The coupling of electricity and gas systems has been ever-augmented with the wide deployment of gas-fired generators,which facilitates the conception of the integrated electricity and gas system(IEGS).Probabilistic en...The coupling of electricity and gas systems has been ever-augmented with the wide deployment of gas-fired generators,which facilitates the conception of the integrated electricity and gas system(IEGS).Probabilistic energy flow(PEF)analysis is usually conducted to assess the operating status of the IEGS by calculating the probability distribution of state variables(e.g.,gas pressure,gas flow,voltage,and power flow).However,multiform time-variant uncertainties can simultaneously reside in the IEGS,including discrete(e.g.,the component failure or functioning)and continuous ones(e.g.,renewable energy outputs).Existing PEF analysis works cannot completely deal with time-variant multiform uncertainties featured with different mathematical characteristics.This limitation hinders the estimation of potential operating risks of the IEGS.To address this,this paper proposes a generalized framework for analyzing the probabilistic energy flow of the IEGS considering multiform uncertainties.Firstly,both time-varying random working states and variable outputs of components are represented as probabilistic models utilizing the L_(z)-transform technique.The probabilistic model is composed of some representative states depicting possible realizations of the component's performance and corresponding probabilities.On this basis,the optimal energy flow(OEF)operator is defined to aggregate probabilistic models of different components to determine probabilistic models of energy flows in the IEGS.Furthermore,multidimensional indices are constructed to comprehensively explore the probabilistic features of energy flows and the impact of probabilistic energy flows on the system performance.In this paper,the system performance mainly refers to the energy-serving capability of the IEGS.Specifically,probabilistic distribution characteristics of energy flows are explicitly displayed by relevant expectations,standard deviations as well as skewnesses.Indices such as the nodal expected gas and electricity not supplied are adopted to evaluate the influence of the probabilistic energy flow on the system performance.Numerical studies reveal that energy flows through different pipelines or power lines present diversified statistical characteristics,which indicates that they are influenced by multiform uncertainties to different extents.展开更多
This article is devoted to the study of variable 2-microlocal Besov-type and Triebel- Lizorkin-type spaces. These variable function spaces are defined via a Fourier-analytical approach. The authors then characterize t...This article is devoted to the study of variable 2-microlocal Besov-type and Triebel- Lizorkin-type spaces. These variable function spaces are defined via a Fourier-analytical approach. The authors then characterize these spaces by means of Q-transforms, Peetre maximal functions, smooth atoms, ball means of differences and approximations by analytic functions. As applications, some re- lated Sobolev-type embeddings and trace theorems of these spaces are Mso established. Moreover, some obtained results, such as characterizations via approximations by analytic functions, are new even for the classical variable Besov and Triebel-Lizorkin spaces.展开更多
文摘为了研究变压器直流偏磁下的铁心损耗,文章以某一核电站500 k V主变压器为例,在二维有限元瞬态场A–φ算法基础下构造了直流偏磁下的变压器二维仿真损耗模型。在仿真中,偏磁直流量从0 A增加至30 A,可得到变压器铁心的损耗分布。结果分析可表明:随着偏磁直流量的增加,励磁电流会产生畸变和较大的偶次谐波,并导致铁心局部损耗增大,其中:铁心主柱与上、下铁轭交接区域的损耗值受到直流偏磁的影响最大,铁心水平路径的损耗值相较于垂直路径受直流偏磁的影响较大。
文摘In this paper,various aspects of the 2D and 3D nonlinear liquid sloshing problems in vertically excited containers have been studied numerically along with the help of a modified-transformation.Based on this new numerical algorithm,a numerical study on a regularly and randomly excited container in vertical direction was conducted utilizing four different cases： The first case was performed utilizing a 2D container with regular excitations.The next case examined a regularly excited 3D container with two different initial conditions for the liquid free surface,and finally,3D container with random excitation in the vertical direction.A grid independence study was performed along with a series of validation tests.An iteration error estimation method was used to stop the iterative solver（used for solving the discretized governing equations in the computational domain） upon reaching steady state of results at each time step.In the present case,this method was found to produce quite accurate results and to be more time efficient as compared to other conventional stopping procedures for iterative solvers.The results were validated with benchmark results.The wave elevation time history,phase plane diagram and surface plots represent the wave nonlinearity during its motion.
文摘Abstract： The shortest path problem in a network G is to find shortest paths between some specified source vertices and terminal vertices when the lengths of edges are given. The structure of the optimal solutions set on the shortest paths is studied in this paper. First, the conditions of having unique shortest path between two distinguished vertices 8 and t in a network G are discussed; Second, the structural properties of 2-transformation ^-G graph G on the shortest-paths for G are presented heavily.
文摘A total synthesis of (E,E)-3,7-dimethyl-2,6-decadiene-1,10-diol, using 1,3-transformation of 2, 3-epoxy alcohol and Claisen rearrangement of allyl vinyl ether as key steps, is described.
基金supported by the Science and Technology Project of State Grid Corporation of China(5108-202218280A-2-448-XG).
文摘The coupling of electricity and gas systems has been ever-augmented with the wide deployment of gas-fired generators,which facilitates the conception of the integrated electricity and gas system(IEGS).Probabilistic energy flow(PEF)analysis is usually conducted to assess the operating status of the IEGS by calculating the probability distribution of state variables(e.g.,gas pressure,gas flow,voltage,and power flow).However,multiform time-variant uncertainties can simultaneously reside in the IEGS,including discrete(e.g.,the component failure or functioning)and continuous ones(e.g.,renewable energy outputs).Existing PEF analysis works cannot completely deal with time-variant multiform uncertainties featured with different mathematical characteristics.This limitation hinders the estimation of potential operating risks of the IEGS.To address this,this paper proposes a generalized framework for analyzing the probabilistic energy flow of the IEGS considering multiform uncertainties.Firstly,both time-varying random working states and variable outputs of components are represented as probabilistic models utilizing the L_(z)-transform technique.The probabilistic model is composed of some representative states depicting possible realizations of the component's performance and corresponding probabilities.On this basis,the optimal energy flow(OEF)operator is defined to aggregate probabilistic models of different components to determine probabilistic models of energy flows in the IEGS.Furthermore,multidimensional indices are constructed to comprehensively explore the probabilistic features of energy flows and the impact of probabilistic energy flows on the system performance.In this paper,the system performance mainly refers to the energy-serving capability of the IEGS.Specifically,probabilistic distribution characteristics of energy flows are explicitly displayed by relevant expectations,standard deviations as well as skewnesses.Indices such as the nodal expected gas and electricity not supplied are adopted to evaluate the influence of the probabilistic energy flow on the system performance.Numerical studies reveal that energy flows through different pipelines or power lines present diversified statistical characteristics,which indicates that they are influenced by multiform uncertainties to different extents.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11571039,11671185,11471042 and 11701174)supported by the Construct Program of the Key Discipline in Hu’nan Province+1 种基金the Scientific Research Fund of Hu’nan Provincial Education Department(Grant No.17B159)the Scientific Research Foundation for Ph.D.Hu’nan Normal University(Grant No.531120-3257)
文摘This article is devoted to the study of variable 2-microlocal Besov-type and Triebel- Lizorkin-type spaces. These variable function spaces are defined via a Fourier-analytical approach. The authors then characterize these spaces by means of Q-transforms, Peetre maximal functions, smooth atoms, ball means of differences and approximations by analytic functions. As applications, some re- lated Sobolev-type embeddings and trace theorems of these spaces are Mso established. Moreover, some obtained results, such as characterizations via approximations by analytic functions, are new even for the classical variable Besov and Triebel-Lizorkin spaces.
