期刊文献+
共找到16篇文章
< 1 >
每页显示 20 50 100
求解二维浅水流动方程的Godunov格式 被引量:34
1
作者 潘存鸿 林炳尧 毛献忠 《水动力学研究与进展(A辑)》 CSCD 北大核心 2003年第1期16-23,共8页
采用网格变换和Strang算子分裂 ,以准确Riemann解为基础 ,建立了求解非平底浅水流动方程的Godunov格式 ,用“水位方程法 (WaterLevelFormulation)”求Riemann解 ,结合中心差分和Riemann解离散底坡项 ,保证了计算格式的和谐性。经验证 ,... 采用网格变换和Strang算子分裂 ,以准确Riemann解为基础 ,建立了求解非平底浅水流动方程的Godunov格式 ,用“水位方程法 (WaterLevelFormulation)”求Riemann解 ,结合中心差分和Riemann解离散底坡项 ,保证了计算格式的和谐性。经验证 ,方法健全、通用 。 展开更多
关键词 二维浅水流动方程 Godunov格式 RIEMANN问题 源项 算子分型
下载PDF
DCS devices based non-linear process control system design for plants with distributed time-delay using particle filter 被引量:3
2
作者 DENG Ming-cong FUJII Ryohei 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第12期3351-3358,共8页
Remote control process system with distributed time-delay has attracted much attention in different fields.In this paper,non-linear remote control of a single tank process system with wireless network is considered.To... Remote control process system with distributed time-delay has attracted much attention in different fields.In this paper,non-linear remote control of a single tank process system with wireless network is considered.To deal with the distributed time-delay in a large-scale plant,the time-delay compensation controller based on DCS devices is designed by using operator theory and particle filter.Distributed control system(DCS)device is developed to monitor and control from the central monitoring room to each process.The particle filter is a probabilistic method to estimate unobservable information from observable information.First,remote control system and experimental equipment are introduced.Second,control system based on an operator theory is designed.Then,process system with distributed time-delay using particle filter is carried out.Finally,the actual experiment is conducted by using the proposed time-delay compensation controller.When estimating with the proposed method,the result is close to the case in which the distributed time-delay does not exist.The effectiveness of the proposed control system is confirmed by experiment results. 展开更多
关键词 non-linear remote control distributed control system particle filter operator theory distributed time-delay
下载PDF
On the Representation of Some Subnormal Operators
3
作者 席俊 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期36-40,共5页
Let T be pure subnormal operator. In this paper necessary and sufficiert conditions that T=N+K are given,where N is normal, K is quasinormal and NK=KN.
关键词 subnormal operators self-dual subnormal operators
下载PDF
Particle swarm optimization for train schedule of Y-type train routing in urban rail transit 被引量:2
4
作者 WEI Zi-wen 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2020年第1期87-93,共7页
The train schedule usually includes train stop schedule,routing scheme and formation scheme.It is the basis of subway transportation.Combining the practical experience of transport organizations and the principle of t... The train schedule usually includes train stop schedule,routing scheme and formation scheme.It is the basis of subway transportation.Combining the practical experience of transport organizations and the principle of the best match between transport capacity and passenger flow demand,taking the minimum value of passenger travel costs and corporation operating costs as the goal,considering the constraints of the maximum rail capacity,the minimum departure frequency and the maximum available electric multiple unit,an optimization model for city subway Y-type operation mode is constructed to determine the operation section of mainline as well as branch line and the train frequency of the Y-type operation mode.The particle swarm optimization(PSO)algorithm based on classification learning is used to solve the model,and the effectiveness of the model and algorithm is verified by a practical case.The results show that the length of branch line in Y-type operation affects the cost of waiting time of passengers significantly. 展开更多
关键词 urban traffic train schedule particle swarm optimization(PSO) classification learning Y-type train routing
下载PDF
DNA Imitation Model: Theory and Application
5
作者 Tuncer Mutlu 《Journal of Chemistry and Chemical Engineering》 2011年第2期110-115,共6页
In this article there is an aim to build a realistic electronic model of this amazing molecule, this perhaps will be the basis for constructing of molecular computers. DNA molecule making the complexes with histones a... In this article there is an aim to build a realistic electronic model of this amazing molecule, this perhaps will be the basis for constructing of molecular computers. DNA molecule making the complexes with histones and other proteines, their electrostatic interaction cause the electrical polarisation and charges formation on this macromolecule, via charges DNA behavoirs are differentiated In this study analysis of signal is setting out by EWB PC simulation program and oscilloscope devices. 展开更多
关键词 DNA COMPLEX electrical polarization SIMULATION
下载PDF
Particle swarm optimization and its application to seismic inversion of igneous rocks 被引量:3
6
作者 Yang Haijun Xu Yongzhong +6 位作者 Peng Gengxin Yu Guiping Chen Meng Duan Wensheng Zhu Yongfeng Cui Yongfu Wang Xingjun 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第2期349-357,共9页
In order to improve the fine structure inversion ability of igneous rocks for the exploration of underlying strata, based on particle swarm optimization(PSO), we have developed a method for seismic wave impedance inve... In order to improve the fine structure inversion ability of igneous rocks for the exploration of underlying strata, based on particle swarm optimization(PSO), we have developed a method for seismic wave impedance inversion. Through numerical simulation, we tested the effects of different algorithm parameters and different model parameterization methods on PSO wave impedance inversion, and analyzed the characteristics of PSO method. Under the conclusions drawn from numerical simulation, we propose the scheme of combining a cross-moving strategy based on a divided block model and high-frequency filtering technology for PSO inversion. By analyzing the inversion results of a wedge model of a pitchout coal seam and a coal coking model with igneous rock intrusion, we discuss the vertical and horizontal resolution, stability and reliability of PSO inversion. Based on the actual seismic and logging data from an igneous area, by taking a seismic profile through wells as an example, we discuss the characteristics of three inversion methods, including model-based wave impedance inversion, multi-attribute seismic inversion based on probabilistic neural network(PNN) and wave impedance inversion based on PSO.And we draw the conclusion that the inversion based on PSO method has a better result for this igneous area. 展开更多
关键词 Particle swarm optimization Seismic inversion Igneous rocks Probabilistic neutral network Model-based inversion
下载PDF
π-Conjugated Unit-Dependent Optical Properties of Linear Conjugated Oligomers
7
作者 Ning Sui Lu Zou +7 位作者 Yun-fei Song Qiu-lin Zhong Ying-hui Wang Xiao-gang Wei Zeng-bin Wang Yu-guang Ma Yan-qiang Yang Han-zhuang Zhang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第3期315-320,共6页
The optical properties of three linear conjugated oligomers (F-P, F-P-F, and P-F-P-F-P), where phenothiazine (P) and fluorene (F) groups arrange alternately, are investigated. With the enhancement of the π-conj... The optical properties of three linear conjugated oligomers (F-P, F-P-F, and P-F-P-F-P), where phenothiazine (P) and fluorene (F) groups arrange alternately, are investigated. With the enhancement of the π-conjugated system, their absorption and emission bands both gradually red shift, and their two-photon properties are also improved. Meanwhile, their fluorescence dynamic traces are analyzed with continuous rate distribution model, exhibiting that their decay rates gradually accelerate and the rate distribution width become narrower. The quantum chemical calculation offers their molecular structures and transition mechanism, showing that the enhancement of π-conjugated system should be responsible for tile improvement of two-photon properties. 展开更多
关键词 OLIGOMER Z-SCAN Fluorescence dynamics
下载PDF
Getting pre-stack time migration travel times from the single square root operator 被引量:6
8
作者 Liu Guofeng Liu Hong +1 位作者 Li Bo Meng Xiaohong 《Applied Geophysics》 SCIE CSCD 2009年第2期129-137,共9页
Improving the focusing capability of pre-stack time migration allows the imaged section to reflect structural characteristics, depth, and interface shape and it is a key step for the preparation of the initial depth m... Improving the focusing capability of pre-stack time migration allows the imaged section to reflect structural characteristics, depth, and interface shape and it is a key step for the preparation of the initial depth migration velocity model. The traditional symmetrical travel time equation is derived based on the assumption of a layered model. It is difficult to achieve the desired effect of focusing in media with strong lateral variation. The nonsymmetrical travel time equation based on Lie algebra and a pseudo-differential operator contains a lateral velocity derivative which can improve the focusing capability even in strongly lateral variable media and also the computation precision of the weight coefficients for relative amplitude preservation. Compared with the symmetrical methods, the nonsymmetrical method is more effective. In this paper, we describe several key steps of nonsymmetric pre-stack travel time calculation and present some test results using synthetic and real data. 展开更多
关键词 single square root operator travel time Lie algebra pseudo-differential operator
下载PDF
Effects of Transverse Field on Internal Energy and Specific Heat of a Molecular-Based Materials
9
作者 JIANG Wei YU Gui-Hong ZHANG Fan WANG Wei JIANG Yuan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第11期965-968,共4页
The molecular-based magnetic materials AFe11 Fe111(C2O4)3 have a honeycomb structure in which FeII (S = 2) and FeIH (S= 5/2) occupy sites alternately. They can be described as mixed spin-2 and spin-5/2 Ising mod... The molecular-based magnetic materials AFe11 Fe111(C2O4)3 have a honeycomb structure in which FeII (S = 2) and FeIH (S= 5/2) occupy sites alternately. They can be described as mixed spin-2 and spin-5/2 Ising model with ferrimagnetic interlayer coupling. The influences of the transverse field on the internal energy and the specific heat of the molecalar-based magnetic system have been studied numerically by using the effective-field theory with self-spin correlations and the differential operator technique. 展开更多
关键词 transverse field molecular-based magnet internal energy specific heat
下载PDF
Integral operators on analytic Morrey spaces 被引量:7
10
作者 LI PengTao LIU JunMing LOU ZengJian 《Science China Mathematics》 SCIE 2014年第9期1961-1974,共14页
In this note,we characterize the boundedness of the Volterra type operator Tg and its related integral operator Ig on analytic Morrey spaces.Furthermore,the norm and essential norm of those operators are given.As a co... In this note,we characterize the boundedness of the Volterra type operator Tg and its related integral operator Ig on analytic Morrey spaces.Furthermore,the norm and essential norm of those operators are given.As a corollary,we get the compactness of those operators. 展开更多
关键词 analytic Morrey space Volterra type operator essential norm
原文传递
Approximation by Modified Summation Integral Type Operators in the L_p Spaces 被引量:2
11
作者 齐秋兰 郭顺生 李建坤 《Journal of Mathematical Research and Exposition》 CSCD 2009年第6期1069-1081,共13页
The generalized summation integral type operators with Beta basis functions are widely studied. At present, the investigations for the properties of these operators are only limited to the functions of bounded variati... The generalized summation integral type operators with Beta basis functions are widely studied. At present, the investigations for the properties of these operators are only limited to the functions of bounded variation. Some authors studied the rate of point-wise rate of convergence, asymptotic formula of Voronovskaja type, and some direct results about these type of operators. The present paper considers the direct, inverse and equivalence theorems of modified summation integral type operators in the Lp spaces. 展开更多
关键词 Beta operators K-FUNCTIONAL moduli of smoothness Riesz-Thorin interpolationtheorem H61der inequality.
下载PDF
Strichartz estimates for parabolic equations with higher order differential operators 被引量:3
12
作者 DING Yong SUN XiaoChun 《Science China Mathematics》 SCIE CSCD 2015年第5期1047-1062,共16页
The present paper first obtains Strichartz estimates for parabolic equations with nonnegative elliptic operators of order 2m by using both the abstract Strichartz estimates of Keel-Tao and the Hardy-LittlewoodSobolev ... The present paper first obtains Strichartz estimates for parabolic equations with nonnegative elliptic operators of order 2m by using both the abstract Strichartz estimates of Keel-Tao and the Hardy-LittlewoodSobolev inequality. Some conclusions can be viewed as the improvements of the previously known ones. Furthermore, an endpoint homogeneous Strichartz estimates on BMOx(Rn) and a parabolic homogeneous Strichartz estimate are proved. Meanwhile, the Strichartz estimates to the Sobolev spaces and Besov spaces are generalized. Secondly, the local well-posedness and small global well-posedness of the Cauchy problem for the semilinear parabolic equations with elliptic operators of order 2m, which has a potential V(t, x) satisfying appropriate integrable conditions, are established. Finally, the local and global existence and uniqueness of regular solutions in spatial variables for the higher order elliptic Navier-Stokes system with initial data in Lr(Rn) is proved. 展开更多
关键词 Strichartz estimates elliptic Navier-Stokes equations higher order elliptic operator POTENTIAL
原文传递
FRACTIONAL INTEGRATION ASSOCIATED TO HIGHER ORDER ELLIPTIC OPERATORS 被引量:1
13
作者 DENGDONGGAO XUMING YANLIXIN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2005年第2期229-238,共10页
The authors prove the Hardy-Littlewood-Sobolev theorems for generalized fractional integrals L?α/2 for 0 < α < n/m, where L is a complex elliptic operator of arbitrary order 2m on Rn.
关键词 Fractional integrals Higher order elliptic operator Hardy-Littlewood- Sobolev theorem
原文传递
Joint eigenfunctions of invariant differential operators on the quaternion Heisenberg group 被引量:1
14
作者 LIU HePing ZHU XiaoJie 《Science China Mathematics》 SCIE 2013年第2期435-441,共7页
Let L be the sublaplacian on the quaternion Heisenberg group N and T the Dirac type operator with respect to central variables of N. In this article, we characterize the He-valued joint eigenfunctions of L and T havin... Let L be the sublaplacian on the quaternion Heisenberg group N and T the Dirac type operator with respect to central variables of N. In this article, we characterize the He-valued joint eigenfunctions of L and T having eigenvalues from the quaternionic Heisenberg fan. 展开更多
关键词 Dirac type operator Heisenberg group joint eigenfunction QUATERNION SUBLAPLACIAN
原文传递
A convolution algorithm to calculate differential cross sections of the Ring effect in the Earth's atmosphere based on rotational Raman scattering 被引量:4
15
作者 HAN Dong CHEN LiangFu +5 位作者 SU Lin TAO JinHua LI ShenShen YU Chao ZHANG Ying HE BaoHua 《Science China Earth Sciences》 SCIE EI CAS 2011年第9期1407-1412,共6页
The Ring effect refers to the filling in of Fraunhofer lines, which is mainly attributed to the rotational Raman scattering of solar spectra by N2 and O2 molecules in the atmosphere. The Ring effect is one of the most... The Ring effect refers to the filling in of Fraunhofer lines, which is mainly attributed to the rotational Raman scattering of solar spectra by N2 and O2 molecules in the atmosphere. The Ring effect is one of the most significant factors affecting the accuracy of retrieving concentrations of atmospheric trace gases, such as NO2 and SO2, from satellite observations through differential optical absorption spectroscopy. First in this study, the solar spectrum measured by the Ozone Monitoring Instrument onboard NASA Aura is convolved with the rotational Raman cross section of the atmosphere, which is calculated from the rotational Raman cross sections of N2 and O2 molecules, and divided by the original solar spectrum. The slowly varying term is removed by fitting it with a cubic polynomial to obtain the differential Ring spectrum. The results agree well with the calculations using a radiative transfer model (R2=0.9663). Second, the differential Ring spectrum is computed using two fixed wavelengths of 410 nm and 488 nm, and the resulting differential Ring spectra are similar to that calculated with varying wavelengths and agree well with the calculation using the radiative transfer model (R2=0.9624 and 0.9639 respectively). The computation time using the fixed wavelength is about 0.128% of that using a varying wavelength. Finally, we found that the frequency spectrum of the Raman cross sections for the atmosphere, N2 molecules and O2 molecules are similar; thus, the Raman cross section of N2 or O2 molecules can be used to compute the approximate Ring effect for simplicity. 展开更多
关键词 Ring effect rotational Raman scattering convolution differential optical absorption spectroscopy
原文传递
Singular and fractional integral operators on preduals of Campanato spaces with variable growth condition
16
作者 NAKAI Eiichi 《Science China Mathematics》 SCIE CSCD 2017年第11期2219-2240,共22页
We investigate the boundedness of singular and fractional integral operators on generalized Hardy spaces defined on spaces of homogeneous type, which are preduals of Campanato spaces with variable growth condition. To... We investigate the boundedness of singular and fractional integral operators on generalized Hardy spaces defined on spaces of homogeneous type, which are preduals of Campanato spaces with variable growth condition. To do this we introduce molecules with variable growth condition. Our results are new even for R^n case. 展开更多
关键词 singular integral fractional integral Hardy space Campanato space variable exponent space of homogeneous type
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部