检索结果-南通市图书馆

Wavelet estimation of the diffusion coefficient in time dependent diffusion models

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2007年第11期50卷 1597-1610页

作者： Ping chen~(1,2+) Jin-de WANG~1 1 department of Mathematics,Nanjing university,Nanjing 210093.{3. 2 School of Science,Nanjing university of Science and technology,Nanjing 210094,{3. department of Mathematics Nanjing University Nanjing 210093 China School of Science Nanjing University of Science technology Nanjing 210094 China

The estimation problem for diffusion coefficients in diffusion processes has been studied in many papers,where the diffusion coefficient function is assumed to be a 1-dimensional bounded Lipschitzian function of the state or the time *** is no previous work for the nonparametric estimation of time-dependent diffusion models where the diffusion coefficient depends on both the state and the *** paper introduces and studies a wavelet estimation of the time-dependent diffusion coefficient under a more general assumption that the diffusion coefficient is a linear growth Lipschitz *** the properties of martingale,we translate the problems in diffusion into the nonparametric regression setting and give the Lr convergence rate.A strong consistency of the estimate is *** this result one can estimate the time-dependent diffusion coefficient using the same structure of the wavelet estimators under any equivalent probability *** example,in finance,the wavelet estimator is strongly consistent under the market probability measure as well as the risk neutral probability measure.

关键词： wavelet estimation time-dependent diffusion coefficient linear growth condition strong consistency

A Study of Multi-sensor Data Fusion System Based on MAS for Nutrient Solution Measurement

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2006年第S3期 264-267页

作者： Feng chen~1 Dafu Yang~1 Bing Wang~2 Xianhu Tan~1 (1.department of Automation,university of Science and {3. of china,Hefei 23.027,china) (2.department of Modern physics,university of Science and {3. of china,Hefei 23.026,china)

For complementarity and redundancy of multi-sensor data fusion (MSDF) system,it is an effective approach for multiple components *** order to measure nutrient solution on-line,a dynamic and complex system under greenhouse environment,sensors should have intelligent properties including self-calibration and self-compensation. Meanwhile,it is necessary for multiple sensors to cooperate and interact for enhancing reliability of multi-sensor system. Because of the properties of multi-agent system (MAS),it is an appropriate tool to study MSDF *** paper proposed an architecture of MSDF system based on MAS for the multiple components measurement of nutrient *** sensor agent's structure and function modules are analyzed and described in detail,the formal definitions are given,*** relations of the sensors are modeled to implement reliability diagnosis of the multi-sensor system,so that the reliability of nutrient control system is *** study offers an effective approach for the study of MSDF.

关键词： multi-sensor data fusion multi-agent system nutrient solution reliability diagnosis.

Early Hydration of Composite Cement with Thermal Activated Coal Gangue

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials Science) 2010年第1期25卷 162-166页

作者：郭伟 department of Material Engineering Yancheng Institute of Technology Institute of Material Science and Engineering Nanjing University of Technology

Composite cement samples were prepared by mixing clinker, gypsum with burnt coal gangues which was calcined at various temperatures. The mechanical strength and Ca（OH）2 content in the cement paste were tested, and the paste composition and microstructure were analyzed by thermogravimetry-differential thermal analysis （TG-DSC）, X-ray diffraction（XRD）, scanning electronic microscopy （SEM） and pore structure analysis. Results demonstrate that the thermal activated coal gangue could accelerate the early hydration of cement clinker obviously, which promotes the gangue hydration itself. The early hydrated products of the cement are C-S-H gel, Ca（OH）2 and AFt. The cement with 3.% （in mass） the gangue exhibits higher mechanical strength, and among all the cement samples the one with the gangue burnt at 700 ℃ displays the highest hydration rate, mechanical strength, the most gel pores and the lowest total porosity.

关键词： blended cement hydration microstructure hydration product

I-V and C-V properties of TiO_2 thin film by pulsed-laser reactive deposition

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第16期43卷 1344-1349页

作者： FU Zhengwen 1, ZHOU Mingfei 1, ZhanG Shengkun 2,chen Lianyao 2 and QIN Qizong 1 1. Laser Chemistry Institute, Fudan university, Shanghai 20043., china 2. department of physics, Fudan university, Shanghai 20043., china Laser Chemistry Institute Fudan University Shanghai China department of Pnysics Fudan University Shanghai China

TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3.ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2/p-Si interface are 1.8×10 12 cm -2 and 2×10 12 eV -1·cm -2, respectively. The conduction mechanisms of as-deposited films are also discussed.

关键词： TiO-2 dielectric properties electrical properties pulsed-laser deposition.

Schwarz-Pick estimates for positive real part holomorphic functions on unit ball and polydisc

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2010年第4期53卷 1017-1024页

作者： LIU Yang 1,& chen ZhiHua 2 1 department of Mathematics,Zhejiang Normal university,Jinhua 3.1004,{3. 2 department of Mathematics,Tongji university,Shanghai 200092,{3. 1. department of Mathematics Zhejiang Normal University Jinhua 321004 China2. Department of Mathematics Tongji University Shanghai 200092 China

We give higher order derivatives Schwarz-Pick estimates for all positive real part holomorphic functions on Bn and D n,and generalize early work on Schwarz-Pick estimate of higher order derivatives for holomorphic fun... 详细信息

关键词： Schwarz-Pick estimate holomorphic function Taylor expansion

A new family of windows——convolution windows and their applications

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2005年第4期48卷 468-480页

作者： ZhanG Jieqiu1,2, LIANG Changhong1 & chen Yanpu3.1. {3. of Applied Math. & Phys., College of Science, Airforce Engineering university, Xi’an 710051, china 2. National Key Laboratory of Antennas and Microwave technology, Xidian university, Xi’an 710071, china 3. Computer Center, Xi’an Communication College, Xi’an 710106, china 1. department of Applied Math. & Phys. College of Science Airforce Engineering University 710051 Xi’an China 2. National Key Laboratory of Antennas and Microwave technology Xidian University 710071 Xi’an China 3. Computer Center Xi’an Communication College 710106 Xi’an China

A new family of windows is constructed by convolutions via a few rectangular windows with same time width and is thus referred to as convolution windows. The expressions of the second-order up to the eighth-order convolution windows in both the time and frequency domains are derived. Their applications in high accuracy harmonic analysis of periodic signals are investigated. Comparisons between the proposed windows and some known windows with the same width shows that, when the synchronous deviation of data sampling is slight, the proposed ones have the least effect of spectral leakage. Therefore, the new windows are well suited for high accuracy harmonic analysis and parameter estimation for periodic signals. The error analysis and computer simulations show that the estimation errors, corresponding to frequency, amplitude and phase of every harmonic component of a signal, are proportional to the pth power of the relative frequency deviation in case of the pth-order convolution window is applied to windowing signal of approximately p cycles. By introducing real time adjustment in sampling interval, the proposed algorithm can adaptively trace signal frequency and lead to less sampling synchronous deviation. The proposed approach has the advantages of easy implementation and high measure precision and can be used in harmonic analysis of quasi-periodic signals whose fundamental frequency drifts slowly with time.

关键词： signal processing harmonic analysis window function convolution window synchronous error spoctral leakage

EPR studies of Mn^(2+) in the Loess Plateau of central china: Implication for variation of the East Asia summer monsoon

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第1期43卷 72-75页

作者： chen Jun\+1, JI Junfeng\+1, SU Yuanxia\+2 and LU Huayu\+3.. department of Earth Sciences, Nanjing university, Nanjing 210093. {3. 2. Center of Material Analysis, Nanjing university, Nanjing 210093. {3. 3. Xi’an Laboratory of Loess and Qu department of Earth Sciences Nanjing University Nanjing China Center of Material Analysis Nanjing University Nanjing China Xi’an Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an China

Mn 2+ EPR intensity recorded in the Chinese loess_paleosol sequence shows close correlation with magnetic susceptibility and Sr content as well as the oscillation of paleoclimate. Thus Mn 2+ EPR signal can serve as an... 详细信息

关键词： paleomonsoon loess paleosol EPR signal of Mn 2+

Incoherent control of two classes of finite-level quantum systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2011年第4期22卷 679-683页

作者： Chunlin chen 1,2 and Zhenquan Qin 3.1.department of Control and System Engineering,Nanjing university,Nanjing 210093.P.R.{3. 2.State Key Laboratory for Novel Software technology,Nanjing university,Nanjing 210093.P.R.{3. 3.School of Software,Dalian university of technology,Dalian 116620,P.R.{3. department of Control and System Engineering Nanjing University Nanjing 210093 P. R. China State Key Laboratory for Novel Software technology Nanjing University Nanjing 210093 P. R. China School of Software Dalian University of Technology Dalian 116620 P. R. China

The incoherent control of finite-level quantum systems is investigated. Following a brief introduction to coherent control paradigms in quantum control, a control problem that can not be accomplished using only coherent control is presented. For such a control problem, it is proved that it can be accomplished using incoherent control based on projective measurement and coherent control for two classes of finite-level quantum systems, i.e., eigenstate controllable quantum systems and wavefunction controllable quantum systems.

关键词： quantum control eigenstate controllability wavefunction controllability coherent control incoherent control.

Higher order bulk characteristic parameters of asymmetric nuclear matter

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 124-129页

作者： chen LieWen1,2 1department of physics, S{3.ghai Jiao Tong university, S{3.ghai 200240, china 2Center of Theoretical Nuclear physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 73.000, china 1. department of physics Shanghai Jiao Tong University Shanghai 200240 China 2. Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-3.5±95) MeV and I0 = (1473.680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (224 ± 3.5) MeV, Isym = (-13.9 ± 2025) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2ρ0 while the symmetry energy up to 2ρ0 can be well described by Esym(ρ0), L, and Ksym.

关键词： equations of state of nuclear matter forces in hadronic systems and effective interactions symmetry energy nuclear density functional theory and extensions asymmetric matter neutron matter