期刊文献+
共找到5,072篇文章
< 1 2 250 >
每页显示 20 50 100
Six New Sets of the Non-Elementary Jef-Family-Functions that Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
1
作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2023年第4期1077-1097,共21页
In this paper, we define some new sets of non-elementary functions in a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We are usi... In this paper, we define some new sets of non-elementary functions in a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. The key is to start with a non-elementary integral function, differentiating and inverting, and then define a set of three functions that belong together. Differentiating these functions twice gives second-order nonlinear ODEs that have the defined set of functions as solutions. We will study some of the second-order nonlinear ODEs, especially those that exhibit limit cycles. Using the methods described in this paper, it is possible to define many other sets of non-elementary functions that are giving solutions to some second-order nonlinear autonomous ODEs. 展开更多
关键词 Non-Elementary functions second-order Nonlinear Autonomous ODE Limit Cycle
下载PDF
Second-Order Correlation Function for Asymmetric-to-Symmetric Transitions due to Spectrally Indistinguishable Biexciton Cascade Emission
2
作者 武雪飞 窦秀明 +7 位作者 丁琨 周鹏宇 倪海桥 牛智川 朱海军 江德生 赵翠兰 孙宝权 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第12期65-69,共5页
We report the observed photon bunching statistics of biexciton cascade emission at zero time delay in single quantum dots by second-order correlation function g(2) (T) measurements under continuous wave excitation... We report the observed photon bunching statistics of biexciton cascade emission at zero time delay in single quantum dots by second-order correlation function g(2) (T) measurements under continuous wave excitation. It is found that the bunching phenomenon is independent of the biexciton binding energy when it varies from 0.59 meV to nearly zero. The photon bunching takes place when the exeiton photon is not spectrally distinguishable from the biexciton photon, and either of them can trigger the %tart' in a Hanbury-Brown and Twiss setup. However, if the exciton energy is spectrally distinguishable from the biexciton, the photon statistics will become asymmetric and a cross-bunching lineshape can be obtained. The theoretical calculations based on a model of three-level rate-equation analysis are consistent with the result of g(2)(τ) correlation function measurements. 展开更多
关键词 second-order correlation function for Asymmetric-to-Symmetric Transitions due to Spectrally Indistinguishable Biexciton Cascade Emission
下载PDF
FROM WAVE FUNCTIONS TO TAU-FUNCTIONS FOR THE VOLTERRA LATTICE HIERARCHY
3
作者 付昂 李明金 杨迪 《Acta Mathematica Scientia》 SCIE CSCD 2024年第2期405-419,共15页
For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functio... For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functions of the solution and use them to give an expression of the matrix resolvent;based on this we obtain a new formula for the k-point functions for the Volterra lattice hierarchy in terms of wave functions.As an application,we give an explicit formula of k-point functions for the even GUE(Gaussian Unitary Ensemble)correlators. 展开更多
关键词 volterra lattice hierarchy matrix-resolvent method wave functions even GUE correlators
下载PDF
Classification of Service Functions in the Life Circle of Beijing Subway Line 7
4
作者 SUN Shuai XIANG Zixiong 《Journal of Landscape Research》 2024年第4期21-26,共6页
As a key node for the surrounding area,metro stations are closely connected with the surrounding urban space and develop cooperatively.Different types of metro stations have differences in land use and functional posi... As a key node for the surrounding area,metro stations are closely connected with the surrounding urban space and develop cooperatively.Different types of metro stations have differences in land use and functional positioning.This paper mainly used the methods of Tyson polygon,kernel density analysis and correlation analysis,based on POI data,to classify the stations of Beijing Metro Line 7.This paper made a detailed analysis of commercial subway stations,and analyzed the distribution characteristics of commercial metro stations on Line 7. 展开更多
关键词 POI data Kernel density analysis correlation analysis function analysis around metro station
下载PDF
Application of Serum Apelin and MMP-9 in Evaluation of Silicosis and Their Correlation with Lung Function
5
作者 Gaocai XIONG Yuanfeng YANG +3 位作者 Jiasong LI Tingqian LIU Bingbing HE Zhuoling LIU 《Agricultural Biotechnology》 CAS 2023年第1期39-42,共4页
[Objectives]This study was conducted to explore the combination of serum Apelin and MMP-9 in the assessment of silicosis and their correlation with lung function. [Methods] From January 2020 to January 2021, eight pat... [Objectives]This study was conducted to explore the combination of serum Apelin and MMP-9 in the assessment of silicosis and their correlation with lung function. [Methods] From January 2020 to January 2021, eight patients with silicosis(including 3, 2 and 3 patients with silicosis in stages I, II and III respectively) were selected as the observation group, and eight persons frees of silicosis were selected as the control group during the same period. All patients were detected for serum APJ endogenous ligand(Apelin) of G protein-coupled receptor, matrix metalloproteinase-9(MMP-9) and pulmonary function indexes. The levels of serum Apelin and MMP-9 and lung function in the two groups were compared, and the correlation between serum Apelin and MMP-9 indexes and lung function was analyzed. [Results] The serum Apelin and lung function in the observation group were lower than those in the control group, and the level of MMP-9 in the observation group was higher than that in the control group, and the differences were statistically significant(P<0.05). The MMP-9 index in patients with silicosis in stage III was higher than those in patients with silicosis in stage II and stage I, and the MMP-9 index in patients with silicosis in stage II was higher than that in patients with silicosis in stage I, and the differences were statistically significant(P<0.05). The serum Apelin and lung function indexes of patients with silicosis in stage III were lower than those of patients with silicosis in stage II and stage I, and the serum Apelin and lung function indexes of patients with silicosis in stage II were lower than those of patients with silicosis in stage I, and the differences were statistically significant(P<0.05). The correlation analysis showed a positive correlation between serum Apelin and lung function indexes, and a negative correlation between MMP-9 and lung function indexes. [Conclusions] A lower serum Apelin and a higher MMP-9 value in patients with silicosis indicate severer lung function impairment, and the combined detection of serum Apelin and MMP-9 is conducive to effective evaluation of the disease of silicosis. The serum Apelin index was negatively correlated with silicosis, and the level of MMP-9 was positively correlated with silicosis, which could provide a scientific basis for clinical diagnosis and treatment. 展开更多
关键词 Serum Apelin MMP-9 SILICOSIS Condition assessment Pulmonary function correlation study
下载PDF
Correlation Degree and Correlation Coefficient of Multi-Output Functions 被引量:1
6
作者 JUGui-zhi ZHAOYa-qun 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第1期195-198,共4页
We present definitions of the correlation degree and correlation coefficient of multi-output functions. Two relationships about the correlation degree of multi-output functions are proved. One is between the correlati... We present definitions of the correlation degree and correlation coefficient of multi-output functions. Two relationships about the correlation degree of multi-output functions are proved. One is between the correlation degree and independency, the other is between the correlation degree and balance. Especially the paper discusses the correlation degree of affine multioutput functions. We demonstrate properties of the correlation coefficient of multi-output functions. One is the value range of the correlation coefficient, one is the relationship between the correlation coefficient and independency, and another is the sufficient and necessary condition that two multi-output functions are equivalent to each other. 展开更多
关键词 Key words multi output functions independency correlation degree BALANCE correlation coefficient
下载PDF
An Attempt to Make Non-Elementary Functions That Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs 被引量:2
7
作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2022年第1期56-67,共12页
In this paper, we define an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, desc... In this paper, we define an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. The key is to start with a non-elementary integral function, differentiating and inverting, and then define a set of functions. Differentiating these functions twice give second-order nonlinear ODEs that have the defined set of functions as solutions. 展开更多
关键词 Non-Elementary functions second-order Nonlinear Autonomous ODE
下载PDF
Walsh Spectral Characteristics and the Auto-Correlation Function Characteristics of Forming Orthomorphic Permutations of Multi-Output Functions 被引量:4
8
作者 ZHAO Yaqun WANG Jue 《Wuhan University Journal of Natural Sciences》 CAS 2006年第6期1895-1898,共4页
Orthomorphic permutations have good characteristics in cryptosystems. In this paper, by using of knowledge about relation between orthomorphic permutations and multi-output functions, and conceptions of the generalize... Orthomorphic permutations have good characteristics in cryptosystems. In this paper, by using of knowledge about relation between orthomorphic permutations and multi-output functions, and conceptions of the generalized Walsh spectrum of multi-output functions and the auto-correlation function of multi-output functions to investigate the Walsh spectral characteristics and the auto-correlation function characteristics of orthormophic permutations, several results are obtained. 展开更多
关键词 orthomorphic permutation multi-output functions walsh spectral auto-correlation function
下载PDF
Improvement of a new rotation function for molecular replacement by designing new scoring functions and dynamic correlation coefficient
9
作者 江凡 丁玮 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期354-359,共6页
A previously published new rotation function has been improved by using a dynamic correlation coefficient as well as two new scoring functions of relative entropy and mean-square-residues to make the rotation function... A previously published new rotation function has been improved by using a dynamic correlation coefficient as well as two new scoring functions of relative entropy and mean-square-residues to make the rotation function more robust and independent of a specific set of weights for scoring and ranking. The previously described new rotation function calculates the rotation function of molecular replacement by matching the search model directly with the Patterson vector map. The signal-to-noise ratio for the correct match was increased by averaging all the matching peaks. Several matching scores were employed to evaluate the goodness of matching. These matching scores were then combined into a single total score by optimizing a set of weights using the linear regression method. It was found that there exists an optimal set of weights that can be applied to the global rotation search and the correct solution can be ranked in the top 100 or less. However, this set of optimal weights in general is dependent on the search models and the crystal structures with different space groups and cell parameters. In this work, we try to solve this problem by designing a dynamic correlation coefficient. It is shown that the dynamic correlation coefficient works for a variety of space groups and cell parameters in the global search of rotation function. We also introduce two new matching scores: relative entropy and mean-square-residues. Last but not least, we discussed a valid method for the optimization of the adjustable parameters for matching vectors. 展开更多
关键词 molecular replacement rotation function global search correlation coefficient
下载PDF
Momentum distribution and non-local high order correlation functions of 1D strongly interacting Bose gas
10
作者 EJKP Nandani Xi-Wen Guan 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期138-151,共14页
The Lieb-Liniger model is a prototypical integrable model and has been turned into the benchmark physics in theoretical and numerical investigations of low-dimensional quantum systems. In this note, we present various... The Lieb-Liniger model is a prototypical integrable model and has been turned into the benchmark physics in theoretical and numerical investigations of low-dimensional quantum systems. In this note, we present various methods for calculating local and nonlocal M-particle correlation functions, momentum distribution, and static structure factor. In particular, using the Bethe ansatz wave function of the strong coupling Lieb-Liniger model, we analytically calculate the two-point correlation function, the large moment tail of the momentum distribution, and the static structure factor of the model in terms of the fractional statistical parameter a = 1 - 2/γ, where γ, is the dimensionless interaction strength. We also discuss the Tan's adiabatic relation and other universal relations for the strongly repulsive Lieb-Liniger model in terms of the fractional statistical parameter. 展开更多
关键词 correlation function momentum distributions structure factor contact
下载PDF
Dynamical correlation functions of the quadratic coupling spin-Boson model
11
作者 郑大川 同宁华 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第6期81-86,共6页
The spin-boson model with quadratic coupling is studied using the bosonic numerical renormalization group method.We focus on the dynamical auto-correlation functions CO(ω), with the operator taken as σx, σz, and ... The spin-boson model with quadratic coupling is studied using the bosonic numerical renormalization group method.We focus on the dynamical auto-correlation functions CO(ω), with the operator taken as σx, σz, and X, respectively. In the weak-coupling regime α 〈 αc, these functions show power law ω-dependence in the small frequency limit, with the powers 1 + 2s, 1 + 2s, and s, respectively. At the critical point α = αc of the boson-unstable quantum phase transition, the critical exponents yO of these correlation functions are obtained as yσx= yσz= 1-2s and yX=-s, respectively. Here s is the bath index and X is the boson displacement operator. Close to the spin flip point, the high frequency peak of Cσx(ω) is broadened significantly and the line shape changes qualitatively, showing enhanced dephasing at the spin flip point. 展开更多
关键词 quadratic-coupling spin-boson model numerical renormalization group quantum phase transition dynamical correlation function
下载PDF
Boundary Correlation Functions of the gl(1|1) Supersymmetric Vertex Model
12
作者 ZHANG Chen-Jun ZHOU Jian-Hua YUE Rui-Hong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第7期17-22,共6页
The gl(1/1) supersymmetric vertex model with domain wall boundary conditions (DWBC) on an N × N square lattice is considered. We derive the reduction formulae for the one-point boundary correlation functions ... The gl(1/1) supersymmetric vertex model with domain wall boundary conditions (DWBC) on an N × N square lattice is considered. We derive the reduction formulae for the one-point boundary correlation functions of the model. The determinant representation for the boundary correlation functions is also obtained. 展开更多
关键词 domain wall boundary conditions partition function boundary correlation function
下载PDF
Second-Order Duality for Continuous Programming Containing Support Functions
13
作者 Iqbal Husain Mashoob Masoodi 《Applied Mathematics》 2010年第6期534-541,共8页
A second-order dual problem is formulated for a class of continuous programming problem in which both objective and constrained functions contain support functions, hence it is nondifferentiable. Under second-order in... A second-order dual problem is formulated for a class of continuous programming problem in which both objective and constrained functions contain support functions, hence it is nondifferentiable. Under second-order invexity and second-order pseudoinvexity, weak, strong and converse duality theorems are established for this pair of dual problems. Special cases are deduced and a pair of dual continuous problems with natural boundary values is constructed. A close relationship between duality results of our problems and those of the corresponding (static) nonlinear programming problem with support functions is briefly outlined. 展开更多
关键词 Continuous PROGRAMMING second-order INVEXITY second-order PSEUDOINVEXITY second-order DUALITY Nonlinear PROGRAMMING Support functions Natural Boundary VALUES
下载PDF
Generating functions for powers of second-order recurrence sequences
14
作者 王晓霞 李梅 《Journal of Shanghai University(English Edition)》 CAS 2011年第6期517-521,共5页
For the sequences satisfying the recurrence relation of the second order,the generating functions for the products of the powers of these sequences are established.This study was from Carlita and Riordan who began a s... For the sequences satisfying the recurrence relation of the second order,the generating functions for the products of the powers of these sequences are established.This study was from Carlita and Riordan who began a study on closed form of generating functions for powers of second-order recurrence sequences.This investigation was completed by Stnica.Inspired by the recent work of Istva'n about the non-closed generating functions of the products of the powers of the second-order sequences,the authors give several extensions of Istva'n's results in this paper. 展开更多
关键词 generating function second-order sequence the Binet formula
下载PDF
On Two New Groups of Non-Elementary Functions That Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
15
作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2022年第3期703-713,共11页
In this paper, we define a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We will also define a group of solutions x(t) that are ... In this paper, we define a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We will also define a group of solutions x(t) that are equal to the amplitude. This is a generalized amplitude function. We are using Abel’s methods, described by Armitage and Eberlein. And finally, we define an exponential function whose exponent is the product of a complex number and the upper limit of integration in a non-elementary integral that can be arbitrary. At least three groups of non-elementary functions are special cases of this complex function. 展开更多
关键词 Non-Elementary functions second-order Nonlinear Autonomous ODE
下载PDF
Four New Examples of the Non-Elementary Expo-Elliptic Functions That Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
16
作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2022年第4期1304-1324,共21页
In this paper, we define four new examples of the non-elementary expo-elliptic functions. This is an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elem... In this paper, we define four new examples of the non-elementary expo-elliptic functions. This is an exponential function whose exponent is the product of a real number and the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. We will study some of the second-order nonlinear ODEs, especially those that exhibit limit cycles, and systems of nonlinear ODEs that these functions are giving solutions to. 展开更多
关键词 Non-Elementary functions second-order Nonlinear Autonomous ODE
下载PDF
ENUMERATING CORRELATION-IMMUNE BOOLEAN FUNCTIONS OF ORDER ONE
17
作者 Tian Haijian Yang Yixian(Dept. of Inform. Eng., Beijing Univ. of Posts and Telecomm., Beijing 100088)Wang Jianyu( Carleton University of Canada) 《Journal of Electronics(China)》 1998年第1期50-57,共8页
A large class of linear structural functions(LSF) satisfying the condition of correlational immunity of order one are constructed by studying the linear structural Boolean functions. With these new founded functions, ... A large class of linear structural functions(LSF) satisfying the condition of correlational immunity of order one are constructed by studying the linear structural Boolean functions. With these new founded functions, the known enumeration bounds of correlation-immune functions of order one are greatly improved. In fact, the best, up to now, lower bound is found. 展开更多
关键词 BOOLEAN function STREAM ciphers correlation-immune function
下载PDF
ON THE RUIN FUNCTIONS FOR A CORRELATED AGGREGATE CLAIMS MODEL WITH POISSON AND ERLANG RISK PROCESSES 被引量:11
18
作者 刘艳 杨文权 胡亦钧 《Acta Mathematica Scientia》 SCIE CSCD 2006年第2期321-330,共10页
This article considers a risk model as in Yuen et al. (2002). Under this model the two claim number processes are correlated. Claim occurrence of both classes relate to Poisson and Erlang processes. The formulae is ... This article considers a risk model as in Yuen et al. (2002). Under this model the two claim number processes are correlated. Claim occurrence of both classes relate to Poisson and Erlang processes. The formulae is derived for the distribution of the surplus immediately before ruin, for the distribution of the surplus immediately after ruin and the joint distribution of the surplus immediately before and after ruin. The asymptotic property of these ruin functions is also investigated. 展开更多
关键词 correlated aggregate claims Poisson process Erlang process ruin functions
下载PDF
Weighted Multi-sensor Data Level Fusion Method of Vibration Signal Based on Correlation Function 被引量:7
19
作者 BIN Guangfu JIANG Zhinong +1 位作者 LI Xuejun DHILLON B S 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第5期899-904,共6页
As the differences of sensor's precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery... As the differences of sensor's precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault diagnosis.The traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left out.To enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration signals.The approach doesn't require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion process.It gives greater weighted value to the greater correlation measure of sensor signals,and vice versa.The approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor's own-information to determine the weighted value.Moreover,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually small.Through the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is taken.Finally,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic adaptability.Meantime,the approach is adaptable and easy to use,can be applied to other areas of vibration measurement. 展开更多
关键词 vibration signal MULTI-SENSOR data level fusion correlation function weighted value
下载PDF
Closed-form steady-state solutions for forced vibration of second-order axially moving systems
20
作者 Jingming FAN Bo CHEN Yinghui LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第10期1701-1720,共20页
Second-order axially moving systems are common models in the field of dynamics, such as axially moving strings, cables, and belts. In the traditional research work, it is difficult to obtain closed-form solutions for ... Second-order axially moving systems are common models in the field of dynamics, such as axially moving strings, cables, and belts. In the traditional research work, it is difficult to obtain closed-form solutions for the forced vibration when the damping effect and the coupling effect of multiple second-order models are considered.In this paper, Green's function method based on the Laplace transform is used to obtain closed-form solutions for the forced vibration of second-order axially moving systems. By taking the axially moving damping string system and multi-string system connected by springs as examples, the detailed solution methods and the analytical Green's functions of these second-order systems are given. The mode functions and frequency equations are also obtained by the obtained Green's functions. The reliability and convenience of the results are verified by several examples. This paper provides a systematic analytical method for the dynamic analysis of second-order axially moving systems, and the obtained Green's functions are applicable to different second-order systems rather than just string systems. In addition, the work of this paper also has positive significance for the study on the forced vibration of high-order systems. 展开更多
关键词 Green's function axially moving system closed-form solution second-order model forced vibration Laplace transform
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部