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Wronskian Form Solutions for a Variable Coefficient Kadomtsev-Petviashvili Equation

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Communications in Theoretical Physics 2014年第3期61卷 339-343页

作者： lu Zhuo-Sheng REN Wen-xiu School of Science Beijing University of Posts and Telecommunications Beijing 100876 China School of Science Inner Mongolia University of Technology Hohhot 010051 China

Starting from a simple transformation, and with the aid of symbolic computation, we establish the relationship between the solution of a generalized variable coefficient Kadomtsev–Petviashvili(vKP) equation and the solution of a system of linear partial differential equations. According to this relation, we obtain Wronskian form solutions of the vKP equation, and further present N-soliton-like solutions for some degenerated forms of the vKP equation. Moreover,we also discuss the influences of arbitrary constants on the soliton and N-soliton solutions of the KPII equation.

关键词： variable coefficient KP equation wronsian form solution multi-soliton-like solution symboliccomputation

Synthesis, Crystal Structure and Fluorescene of a One-dimensional Compound {CdI_2(2,2′-bipy)}_n

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Chinese Journal of Structural Chemistry 2007年第2期26卷 211-213页

作者： GUO Hong-Xu DU zi-Xian YOU xiu-Li WANG Qing-Hua Department of Chemistry ＆ Environmental Scicence Zhangzhou Teachers College Zhangzhou 363000 China Fujian Longyan Center for Disease Control ＆ Prevention Longyan 364000 China

The title compound, {CdI2（2,2＇-bipy）}n, was prepared by the hydrothermal reaction of CdI2 and 2,2＇-bipy in an aqueous solution, and its crystal structure was determined by X-ray single-crystal analysis. Crystallographic data for 1： C10H8N2CdI2, monoclinic system, space group C2/c, a = 16.927（1）, b = 10.0925（7）, c = 7.7422（3） A, β = 106.0629（4）°, V = 1271.00（14） A^3, Z = 4, F（000） = 944,/a = 6.546 mm^-1, Dc= 2.730 g/cm^3, Mr = 522.38, the final R = 0.0309 and wR = 0.0805 for 1310 observed reflections （I 〉 20（I））. X-ray crystal structure analysis shows that the Cd atom is coordinated by four iodines and two N atoms from one 2,2＇-bipy to form an 1-D chain-like structure through bridging iodines. The fluorescene of the title compound was also discussed.

关键词： cadmium( Ⅱ ) iodide 2,2'-bipyridine one-dimensionalchain-like crystal structure fluorescence

Hydrolysis kinetics of benzyl phenyl ether in high temperature liquid water

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Chinese Chemical Letters 2011年第6期22卷 733-737页

作者： Xiao Yu Wu xiu Yang lu Department of Chemical and Biological Engineering Zhejiang University Hangzhou 310027 China

The application of high temperature liquid water（HTLW） to decomposition of lignin as efficient and green solution for phenolic compounds recovery was *** phenyl ether（BPE）,the lignin model compound,was treated at temperatures ranging from 220 to 250℃.BPE undergo hydrolysis in HTLW,and main products were phenol and benzyl alcohol with the minimum selectivities of 75.7%and 82.8%,*** temperature led to higher selectivity in 220-250℃temperature *** kinetics on BPE hydrolysis was studied and the activation energy was determined as 150.3±12.5 kJ/mol with the first-order kinetic *** on products distribution,the reaction mechanism for decomposition of benzyl phenyl ether was *** investigated process provides insights into the design of a commercial method for utilization of lignin.

关键词： Hydrolysis Kinetics Benzyl phenyl ether High temperature liquid water Lignin model compound

Effects of microstructure on uniaxial strength asymmetry of open-cell foams

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Applied Mathematics and Mechanics(English Edition) 2015年第1期36卷 37-46页

作者： zi-xing lu Ji-xiang HUANG Ze-shuai YUAN Institute of Solid Mechanics Beihang University

Based on the elongated Kelvin model, the effect of microstructure on the uniaxial strength asymmetry of open-cell foams is investigated. The results indicate that this asymmetry depends on the relative density, the solid material, the cell morphology, and the strut geometry of open-cell foams. Even though the solid material has the same tensile and compressive strength, the tensile and compressive strength of open-cell foams with asymmetrical sectional struts are still different. In addition, with the increasing degree of anisotropy, the uniaxial strength as well as the strength asymmetry increases in the rise direction but reduces in the transverse direction. Moreover, the plastic collapse ratio between two directions is verified to depend mainly on the cell morphology. The predicted results are compared with Gibson and Ashby＇s theoretical results as well as the experimental data reported in the literature, which validates that the elongated Kelvin model is accurate in explaining the strength asymmetry presented in realistic open-cell foams.

关键词： open-cell foam microstructure strength Kelvin model

Experimental research on charging characteristics of a solar photovoltaic system by the pressure-control method

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 470-474页

作者： Hua ZHU Zhang-lu XU zi-juan CAO Institute of Thermal Science and Power Systems Zhejiang University Hangzhou 310027 China

The charging characteristics of the valve-regulated lead acid(VRLA) battery driven by solar energy were experimentally studied through the pressure-control method in this *** aims of the research were to increase charging efficiency to make the most of solar energy and to improve charging quality to prolong life of *** charging process of a 12 V 12 A·h VRLA battery has been tested under the mode of a stand-alone photovoltaic(PV) *** show that the pressure-control method can effectively control PV charging of the VRLA battery and make the best of PV cells through the maximum power point tracking(MPPT).The damage of VRLA battery by excess oxygen accumulation can be avoided through the inner pressure control of VRLA *** such as solar radiation intensity,charging power,inner pressure of the battery,and charging current and voltage during the charging process were measured and analyzed.

关键词： Solar photovoltaic(PV) system Charging characteristics Pressure-control method

Image-based 3D model retrieval using manifold learning

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Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1397-1408页

作者： Pan-pan MU San-yuan ZHANG Yin ZHANG xiu-zi YE Xiang PAN College of Computer Science and Technology Zhejiang University College of Mathematics and Information Science Wenzhou University College of Computer Science and Technology Zhejiang University of Technology

We propose a new framework for image-based three-dimensional(3D) model retrieval. We first model the query image as a Euclidean point. Then we model all projected views of a 3D model as a symmetric positive definite(SPD) matrix, which is a point on a Riemannian manifold. Thus, the image-based 3D model retrieval is reduced to a problem of Euclid-to-Riemann metric learning. To solve this heterogeneous matching problem, we map the Euclidean space and SPD Riemannian manifold to the same high-dimensional Hilbert space, thus shrinking the great gap between them. Finally, we design an optimization algorithm to learn a metric in this Hilbert space using a kernel trick. Any new image descriptors, such as the features from deep learning, can be easily embedded in our framework. Experimental results show the advantages of our approach over the state-of-the-art methods for image-based 3D model retrieval.

关键词： Model retrieval Euclidean space Riemannian manifold Hilbert space Metric learning

Adaptive foreground and shadow segmentation using hidden conditional random fields

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 586-592页

作者： CHU Yi-ping YE xiu-zi QIAN Jiang ZHANG Yin ZHANG San-yuan School of Computer Science State Key Lab. of CAD ＆ CG Zhejiang University Hangzhou 310027 China

Video object segmentation is important for video surveillance, object tracking, video object recognition and video editing. An adaptive video segmentation algorithm based on hidden conditional random fields (HCRFs) is proposed, which models spatio-temporal constraints of video sequence. In order to improve the segmentation quality, the weights of spatio-temporal con- straints are adaptively updated by on-line learning for HCRFs. Shadows are the factors affecting segmentation quality. To separate foreground objects from the shadows they cast, linear transform for Gaussian distribution of the background is adopted to model the shadow. The experimental results demonstrated that the error ratio of our algorithm is reduced by 23% and 19% respectively, compared with the Gaussian mixture model (GMM) and spatio-temporal Markov random fields (MRFs).

关键词： Video segmentation Shadow elimination Hidden conditional random fields (HCRFs) On-line learning

SCI citation analysis and impact factor prediction of JZUS-A in 2008

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 149-150页

作者： zi-yang ZHAI xiu-fang WU Yue-hong (Helen) ZHANG Editors Journals of Zhejiang University SCIENCE (A &B) Zhejiang University Press Hangzhou 310027 China

Journal of Zhejiang University-SCIENCE A(JZUS-A),its former version named Journal of Zhejiang University-SCIENCE(ISSN 1009-3095),has been covered by Science Citation Index Expanded(SCI-E)since *** now,all the 500 pape... 详细信息

关键词：期刊编辑出版《浙江大学学报》

How Frequently Will the Persistent Heavy Rainfall over the Middle and Lower Yangtze River Basin in Summer 2020 Happen under Global Warming?

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Advances in Atmospheric Sciences 2022年第10期39卷 1673-1692,I0016,I0017页

作者： zi-An GE Lin CHEN Tim LI lu WANG Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science and TechnologyNanjing 210044China International Pacific Research Center and Department of Atmospheric Sciences School of Ocean and Earth Science and TechnologyUniversity of Hawaii at ManoaHonoluluHawaii 96822USA

The middle and lower Yangtze River basin(MLYRB)suffered persistent heavy rainfall in summer 2020,with nearly continuous rainfall for about six consecutive *** the likelihood of persistent heavy rainfall resembling that which occurred over the MLYRB in summer 2020(hereafter 2020PHR-like event)would change under global warming is *** index that reflects maximum accumulated precipitation during a consecutive five-week period in summer(Rx35day)is *** accumulated precipitation index in summer 2020 is 60%stronger than the climatology,and a statistical analysis further shows that the 2020 event is a 1-in-70-year *** model projection results derived from the 50-member ensemble of CanESM2 and the multimodel ensemble(MME)of the CMIP5 and CMIP6 models show that the occurrence probability of the 2020PHR-like event will dramatically increase under global *** on the Kolmogorov-Smirnoff test,one-third of the CMIP5 and CMIP6 models that have reasonable performance in reproducing the 2020PHR-like event in their historical simulations are selected for the future projection *** CMIP5 and CMIP6 MME results show that the occurrence probability of the 2020PHR-like event under the present-day climate will be double under lower-emission scenarios(CMIP5 RCP4.5,CMIP6 SSP1-2.6,and SSP2-4.5)and 3-5 times greater under higher-emission scenarios(3.0 times for CMIP5 RCP8.5,2.9 times for CMIP6 SSP3-7.0,and 4.8 times for CMIP6 SSP5-8.5).The inter-model spread of the probability change is small,lending confidence to the projection *** results provide a scientific reference for mitigation of and adaptation to future climate change.

关键词： persistent heavy rainfall middle and lower Yangtze River basin future projection CMIP5 and CMIP6 models generalized extreme value(GEV)distribution