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Development and application of ergodicity model with FRCM and FLAR for hydrological process

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Science china(Technological sciences) 2009年第2期52卷 379-386页

作者： WANG HongRui1, FENG QiLei2, lin Xin3 & ZENG WenYi4 1 College of Water Science, Key Laboratory for Water and Sediment sciences of the Ministry of Education, beijing normal university. beijing 100875. china 2 school of Science, beijing Institute of Education, beijing 100011, china 3 school of mathematical sciences, beijing normal university. beijing 100875. china 4 College of Information Science and Technology, beijing normal university. beijing 100875. china College of Water Science Key Laboratory for Water and Sediment Sciences of the Ministry of Education Beijing Normal University Beijing China school of Science Beijing Institute of Education Beijing China school of mathematical sciences Beijing Normal University Beijing China College of Information Science and Technology Beijing Normal University Beijing China

In this paper, a new ergodic property analysis model of hydrological process is proposed based on fuzzy-rough c-means clustering (FRCM), autocorrelogram, and fuzzy least absolute regression (FLAR). A precipitation time series (1951―2004) from Shanghai Hydrology Station is then analyzed with the model. The results show that the precipitation time series of April, May, June, and September has er-godic property. We conclude that in the long run, the precipitation of April, May, June, and September will not keep decreasing; it will converge to its mean value in some period.

关键词： hydrological process ergodic autocorrelogram fuzzy-rough c-means clustering fuzzy least absolute regression

On weak solutions for an image denoising-deblurring model

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Applied Mathematics(A Journal of Chinese Universities) 2009年第3期24卷 269-281页

作者： HUANG Hai-yang JIA Chun-yan HUAN Zhong-dan school of mathematical sciences,beijing normal university.Laboratory of Mathematics and ComplexSystems,Ministry of Education,beijing 100875.china school of mathematical sciences Beijing Normal University Beijing China Laboratory of Mathematics and Complex Systems Ministry of Education Beijing China

A new denoising-deblurring model in image restoration is proposed,in which the regularization term carries out anisotropic diffusion on the edges and isotropic diffusion on the regular *** existence and uniqueness of weak solutions for this model are proved,and the numerical model is also *** with the TV diffusion,this model preferably reduces the staircase appearing in the restored images.

关键词： image restoration deblurring-denoising integro-differential equation weak solution

Efficient estimation for additive hazards regression with bivariate current status data

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Science china Mathematics 2012年第4期55卷 763-774页

作者： TONG XingWei 1,,HU Tao 2 & SUN JianGuo 3,4 1 school of mathematical sciences,beijing normal university.beijing 100875.china 2 school of mathematical sciences,Capital normal university.beijing 100048,china 3 school of Mathematics,Jilin university.Changchun 130012,china 4 Department of Statistics,university.of Missouri,Columbia,MO 65211,USA school of mathematical sciences Beijing Normal University Beijing China school of mathematical sciences Capital Normal University Beijing China school of Mathematics Jilin University Changchun China Department of Statistics University of Missouri Columbia USA

This paper discusses efficient estimation for the additive hazards regression model when only bivariate current status data are available. Current status data occur in many fields including demographical studies and tumorigenicity experiments （Keiding, 1991; Sun, 2006） and several approaches have been proposed for the additive hazards model with univariate current status data （linet M., 1998; Martinussen and Scheike, 2002）. For bivariate data, in addition to facing the same problems as those with univariate data, one needs to deal with the association or correlation between two related failure time variables of interest. For this, we employ the copula model and an efficient estimation procedure is developed for inference. Simulation studies are performed to evaluate the proposed estimates and suggest that the approach works well in practical situations. An illustrative example is provided.

关键词： bivariate current status data copula model counting processes efficient estimation joint survivalfunction

Superprocesses arising from interactive stochastic flows

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Science china Mathematics 2006年第4期49卷 451-476页

作者： yan Guojun & LI Zhanbing Medical school, Shantou university. Shantou 515063, china Department of Mathematics, Bejing normal university. beijing 100875. china Medical school Shantou University Shantou China Department of Mathematics Bejing Normal University Beijing China

In this paper, we give a unified construction for superprocesses with dependent spatial motion constructed by Dawson, Li, Wang and superprocesses of stochastic flows constructed by Ma and Xiang. Furthermore, we also g... 详细信息

关键词： superprocess, interactive stochastic flows, martingale problem, dual processes.

Flexible Crystal Heterojunctions of Low-Dimensional Organic Metal Halides Enabling Color-Tunable Space-Resolved Optical Waveguides

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Research 2024年第3期6卷 293-304页

作者： Yuhang lin Shuya Liu Dongpeng yan beijing Key Laboratory of Energy Conversion and Storage Materials and Key Laboratory of RadiopharmaceuticalsMinistry of EducationCollege of ChemistryBeijing Normal UniversityBeijing 100875China.

Molecular luminescent materials with optical waveguide have wide application prospects in light-emitting diodes, sensors, and logic gates. However, the majority of traditional optical waveguide systems are based on brittle molecular crystals, which limited the fabrication, transportation, storage, and adaptation of flexible devices under diverse application situations. To date, the design and synthesis of photofunctional materials with high flexibility, novel optical waveguide, and multi-port color-tunable emission in the same solid-state system remain an open challenge. Here, we have constructed new types of zero-dimensional organic metal halides (Au-4-dimethylaminopyridine [DMAP] and In-DMAP) with a rarely high elasticity and rather low loss coefficients for optical waveguide. Theoretical calculations on the intermolecular interactions showed that the high elasticity of 2 molecular crystalline materials was original from their herringbone structure and slip plane. Based on one-dimensional flexible microrods of 2 crystals and the 2-dimensional microplate of the Mn-DMAP, heterojunctions with multi-color and space-resolved optical waveguides have been fabricated. The formation mechanism of heterojunctions is based on the surface selective growth on account of the low lattice mismatch ratio between contacting crystal planes. Therefore, this work describes the first attempt to the design of metal-halide-based crystal heterojunctions with high flexibility and optical waveguide, expanding the prospects of traditional luminescent materials for smart optical devices, such as logic gates and multiplexers.

关键词： waveguide Crystal elasticity

ENDPOINT ESTIMATE FOR MAXIMAL COMMUTATORS WITH NON-DOUBlinG MEASUES

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Acta Mathematica Scientia 2006年第2期26卷 271-280页

作者：胡国恩孟岩杨大春 Department of Applied Mathematics university.of Information Engineering Zhengzhou 450002China school of mathematical sciences beijing normal university Beijing 100875China

The authors establish the weak type endpoint estimate for the maximal commutators generated by Calderon-Zygmund singular integrals and Orlicz type functions with non-doubling measures.

关键词： Maximal commutator endpoint estimate Orlicz type space non-doubling measure

Theoretical Study on the Pyrolysis Mechanism and Kinetics of 3-Hydroxy-3-Methyl-2-Butanone

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Chinese Chemical Letters 1998年第11期9卷 0-0页

作者： Wen lin FENG Jie Hao CHEN yan WANG (Department of chemistry, beijing normal university. beijing 100875. Department of Chemistry Beijing Normal University Beijing 100875 China

The mechanism and kinetics for the decomposition of 3-hydroxy-3-methyl-2-butanone have been studied by using the ab initio RHF/3-21G method. The calculated activation barrier of the reaction is 249.6kJ/mol which is in reasonable agreement with the experimental data (222.2±3kJ/mol). The calculated results show that the decomposition is a concerted process with hydrogen transferring and bond breaking via a five-membered cyclic transition state. The thermal rate constants of the decomposition are obtained by calculating microcanonical probability fluxes through transition state1.

关键词： Kinetics mechanism theoretical study rate constants

Calculation of the Canonical Rate Constant for the Nonadiabatic Trapping Model Based on Unified Statistical Theory:A Test on The Exchange Reaction H_2+H

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Chinese Chemical Letters 1998年第2期9卷 177-179页

作者： Shu Xia YIN yan WANG and Wen lin FENG(Chemistry Department, Bejing normal university. beijing 100875. Chemistry Department Beijing Normal University Beijing 100875 China

A new approach was employed to calculate the canonical (thermal) rate constant basedon unified statistical theory. All information for the calculation was obtained from ab initio meth-ods. The flux integral for any point of reaction coordinate was calculated by counting the numberof quantum states and applied to determine the dividing surfaces along the intrinsic reaction coor-dinate (IRC). The classical exchange reaction H2+H, as an example, was investigated. The IRC forthe reaction has been traced and detailed information of IRC was carried out at the QCISD/6-311 G** level .The calculated rate constants are well consistent with the experimental results.

关键词： unified statistical theory intrinsic reaction coordinate (IRC) canonical rate constants

Biodegradation of polycyclic aromatic hydrocarbons in sediments from the Daliao River watershed, china

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Journal of Environmental sciences 2009年第7期21卷 865-871页

作者： QUAN Xiangchun, TANG Qian, HE Mengchang, yanG Zhifeng, lin Chunye, GUO Wei State Key Joint Laboratory of Environmental Simulation and Pollution Control, school of Environment, beijing normal university. beijing 100875. china. State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China

The Daliao River, as an important water system in Northeast china, was reported to be heavily polluted by polycyclic aromatic hydrocarbons （PAHs）. Aerobic biodegradations of four selected PAHs （naphthalene, phenanthrene, fluorene and anthracene） alone or in their mixture in river sediments from the Daliao River water systems were studied in microcosm systems. Effects of additional carbon source, inorganic nitrogen and phosphorus, temperature variation on PAHs degradation were also investigated. Results showed that the degradation of phenanthrene in water alone system was faster than that in water-sediment combined system. Degradation of phenanthrene in sediment was enhanced by adding yeast extract and ammonium, but retarded by adding sodium acetate and not significantly influenced by adding phosphate. Although PAHs could also be biodegraded in sediment under low temperature （5~C）, much lower degradation rate was observed. Sediments from the three main streams of the Daliao River water system （the Hun River, the Taizi River and the Daliao River） demonstrated different degradation capacities and patterns to four PAHs. Average removal rates （15 or 19 d） of naphthalene, phenanthrene, fluorene and anthracene by sediment were in the range of 0.062-0.087, 0.005-0.066, 0.008- 0.016 and 0-0.059 mg/（L.d）, respectively. As a result, naphthalene was most easily degraded compound, anthracene was the hardest one. In multiple PAHs systems, the interactions between PAHs influenced each PAH biodegradation.

关键词： biodegradation the Daliao River microcosm polycyclic aromatic hydrocarbon sediment