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International Journal of Digital Earth 2012年第3期5卷 189-201页

作者： wen xu China Centre for Resources Satellite Data and Application Haidian DistrictBeijingChina

Digital Earth is an interdisciplinary field involving space technology,information technology,and *** article introduces the land observation satellite system of China and discusses the requirements for satellite payloads in terms of spatial,temporal,and spectral resolution to establish a Digital *** applications of land satellites under the framework of Digital Earth are introduced from the perspectives of data support,special subject services,and integrated information *** is concluded that China’s land observation satellites and ground processing systems will be fundamental components of the Digital Earth system,in which satellite data and their derived information will serve as the principal information source and greatly promote applications of Digital Earth.

关键词： land satellite Digital Earth spatial information spatial data infrastructure Earth observation

Chemical ecology-driven discovery of bioactive marine natural products as potential drug leads

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Chinese Journal of Natural Medicines 2020年第11期18卷 837-838页

作者： LI xu-wen State Key Laboratory of Dmg Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China

Over the past decades, more and more bioactive marine natural products(MNPs) have attracted numerous chemists and pharmacologists for their medicinal application. Up until now, nearly twenty MNPs-derived drugs have been successfully developed and are available on market. In this special issue, we are please to publish four original articles on MNPs, which represent the currently most studied marine living organisms, soft corals,sponges, and marine derived fungi, from far sea, deep sea or special mangrove living conditions.

关键词： drugs please sponge

Aggregation of the Adsorbed Proteinsin Solution or on the Surface?

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Chinese Chemical Letters 2002年第3期13卷 262-265页

作者： Tong wen xu 不详

The adsorption of bovine serum albumin (BSA) on porous polyethylene (PE) membrane was studied based on adsorption and desorption measurements as well as FTIR analysis. A different mechanism was proposed which showed that a critical concentration existed in the adsorptional process. Below this concentration, the adsorption seems to be conducted in a normal side-on way; above this concentration, the adsorption is in an aggregation way.

关键词： Bovine serum albumin adsorption desorption FTIR.

On rigidity of Clifford torus in a unit sphere

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Applied Mathematics(A Journal of Chinese Universities) 2011年第1期26卷 121-126页

作者： xu Yi-wen xu Zhi-yuana Department of Mathematical Sciences Indiana University-Purdue University Indianapolis 402 N. Blackford St. Indianapolis IN 46202-3267 USA Department of Mathematics Zhejiang Sci-Tech University Hangzhou 310018 China Center of Mathematical Sciences Zhejiang University Hangzhou 310027 China

We extend the scalar curvature pinching theorems due to Peng-Terng, Wei-xu and Suh-Yang. Let M be an n-dimensional compact minimal hypersurface in S^n＋1 satisfying S f4 - f^2 3 ≤1/nS^3 where S is the squared norm of the second fundamental form of M, and fk = ∑λi^k and λi（1 ≤ i ≤ n） are the principal curvatures of M. We prove that there exists a positive constant δ（n）（≥ n/2） depending only on n such that if n ≤ S ≤ n ＋δ（n）, then S ≡ n, i.e., M is one of the Clifford torus S^K （√k/n） × S^n-k （V√n-k/n） for 1≤ k ≤ n - i. Moreover, we prove that if S is a constant, then there exists a positive constant T（n）（≥ n -2/3） depending only on n such that ifn ≤ S 〈 n ＋ τ（n）, then S ≡n, i.e.. M is a Clifford torus.

关键词： Minimal hypersurface rigidity scalar curvature second fundamental form Clifford torus.

Fuzzy Q-learning in continuous state and action space

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The Journal of China Universities of Posts and Telecommunications 2010年第4期17卷 100-109页

作者： xu Ming-liang xu wen-bo Department of Electronic Information Engineering Wuxi City College of Vocational Technology Wuxi 214063 China School of Information Technology Jiangnan University Wuxi 214122 China

An adaptive fuzzy Q-leaming （AFQL） based on fuzzy inference systems （FIS） is proposed. The FIS realized by a normalized radial basis function （NRBF） neural network is used to approach Q-value function, whose input is composed of state and action. The rules of FIS are created incrementally according to the novelty of each element of the pair of state-action. Moreover the premise part and consequent part of the FIS are updated using extended Kalman filter （EKF）. The action that impacts on environment is the one with maximum output of FIS in the current state and generated through optimization method. Simulation results in the wall-following task of mobile robots and the inverted pendulum balancing problem demonstrate that the superiority and applicability of the proposed AFQL method.

关键词： Q-learning FIS continuous adaptation

The Brillouin zones and band gaps of a two-dimensional phononic crystal with parallelogram lattice structure

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Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1013-1019页

作者： HU JiaGuang xu wen School of Physical Science and Technology Yunnan University Department of Math and Physics Wenshan University Institute of Solid State Physics Chinese Academy of Sciences

We present a detailed theoretical study on the acoustic band structure of two-dimensional （2D） phononic crystal. The 2D pho- nonic crystal with parallelogram lattice structure is considered to be formed by rigid solid rods embedded in air. For the circu- lar rods, some of the extrema of the acoustic bands appear in the usual high-symmetry points and, in contrast, we find that some of them are located in other specific lines. For the case of elliptic rods, our results indicate that it is necessary to study the whole first Brillouin zone to obtain rightly the band structure and corresponding band gaps. Furthermore, we evaluate the first and second band gaps using the plane wave expansion method and find that these gaps can be tuned by adjusting the side lengths ratio R, inclined angle 0 and filling fraction F of the parallelogram lattice with circular rods. The results show that the largest value of the first band gap appears at θ=90° and F--0.7854. In contrast, the largest value of the second band gap is at θ=60° and F=0.9068. Our results indicate that the improvement of matching degree between scatterers and lattice pattern, ra- ther than the reduction of structural symmetry, is mainly responsible for the enhancement of the band gaps in the 2D phononic crystal.

关键词： phononic crystal band gap lattice basis vectors plane wave expansion method

Distinct phase transitions and dielectric anomalies in two 4-methylanilinium salts

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Science China Chemistry 2012年第2期55卷 201-207页

作者： ZHANG wen xu RuiJun Ordered Matter Science Research Center Southeast University Nanjing 211189 China

Solid-state phase transitions of 4-methylanilinium perchlorate （4-CH3C6H4NH3.C104, 1） and tetrafluoroborate （4-CH3C6H4- NH3-BF4, 2） were investigated with variable-temperature X-ray single-crystal structure analysis and thermal studies. Both 1 and 2 undergo first-order phase transitions and exhibit distinct dielectric anomalies at 385 and 247 K, respectively.

关键词： organic-inorganic hybrid compounds dielectricity phase transition crystal structure switchable molecular dielectrics

Dechlorination of carbon tetrachloride by the catalyzed Fe-Cu process

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Journal of Environmental Sciences 2007年第7期19卷 792-799页

作者： xu wen-ying GAO Ting-yao The National Engineering Research Center for Urban Pollution Control Tongji University Shanghai 200092 China.

The dectrochemical reduction characteristics of carbon tetrachlofide （CT） were investigated using cyclic voltammetry in this study. In addition, the difference in reduction mechanisms of CT between Master Builders＇ iron and the catalyzed Fe-Cu process was discussed. The results showed that CT was reduced directly on the surface of copper rather than by atomic hydrogen produced at the cathode in the catalyzed Fe-Cu process. The reduction was realized largely by atomic hydrogen in Master Builders＇ iron. The entire CT in 350 ml aqueous solution with 320 mg/L was reduced to trichloromethane and dichloromethane in 2.25 h when 100 g of scrap iron with Fe/Cu ratio of 10：1 （w/w） were used. Moreover, the reduction rate slowed with time. CT could be reduced at acidic, neutral and alkaline pH from solution by Fe-Cu bimetallic media, but the mechanisms were different. The degradation rate was not significantly influenced by pH in the catalyzed Fe-Cu process; in Master Builders＇ iron it clearly increased with decreasing pH. The kinetics of the reductions followed pseudo-first order in both cases. Furthermore, the reductions under acidic conditions proceeded faster than that under the neutral and alkaline conditions. The catalyzed Fe-Cu process was superior to Master Builders＇ iron in treating CT-containing water and this advantage was particularly noticeable under alkaline conditions. The reduction was investigated in the cathode （Cu） and anode （Fe） compartments respectively, the results showed that the direct reduction pathway played an important role in the reduction by the catalyzed Fe-Cu process. The catalyzed Fe-Cu process is of practical value.

关键词： carbon tetrachloride electrochemical reduction characteristics catalyzed Fe-Cu process reduction mechanisms

Water Dissociation Phenomena on a Bipolar Membrane──Current-voltage Curve in Relation with IonicTransport and Limiting Current Density

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Chemical Research in Chinese Universities 2001年第4期17卷 457-464页

作者： xu Tong-wen YANG Wei-hua Department of Applied Chemistry University of Science and Technology of ChinaHefei 230026P.R.China

The water dissociation mechanism on a bipolar membrane under the electrical field was investigated and characterized in terms of ionic transport and limiting current density. It is considered that the depletion layer exists at the junction of a bipolar membrane, which is coincided with the viewpoint of the most literatures, but we also consider that the thickness and conductivity of this layer is not only related with the increase of the applied voltage but also with the limiting current density. Below the limiting current density, the thickness of the depletion layer keeps a constant and the conductivity decreases with the increase of the applied voltage; while above the limiting current density, the depletion thickness will increase with the increase of the applied voltage and the conductivity keeps a very low constant. Based on the data reported in the literatures and independent determinations, the limiting current density was calculated and the experimental curves Ⅰ-Ⅴ in the two directions were com

关键词： Bipolar membrane Water dissociation Ionic transport Limiting current density

Microstructures and mechanical properties of low carbon fishplate materials

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Acta Metallurgica Sinica(English Letters) 2010年第3期23卷 176-184页

作者： Fumin xu Kai wen Yi TAN School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China

Two kinds of low carbon bainite materials were developed for fishplate *** microstructures and mechanical properties were measured in *** results showed that one material was composed of fine granular bainite with the yield strength of 722 MPa at room temperature and 738 MPa at-55℃, and elongation percentages of 60.7% and 41.7%, *** other one had a meta-bainite microstructure with corresponding strengths of 568.5 MPa and 700 MPa, elongation percentages of 63.5% and 67.1%, *** values are all superior to the home-made B7 steel and the fishplate materials made in *** major strengthening mechanisms were discussed and attributed to the solid solution, complex phases, fine grain and dislocation strengthening.

关键词： Fishplate Microstructure Mechanical property Strengthening