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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

Caution in building a Burgers circuit for studying secondary dislocations

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Journal of Materials Science & Technology 2019年第6期35卷 1192-1197页

作者： wen-Sheng xu wen-Zheng Zhang Key Laboratory of Advanced Materials (MOE) School of Materials Science and EngineeringTsinghua University

As the Burgers vector of a secondary dislocation may not conform to the translation vectors in the periodic pattern in a high-resolution transmission electron microscope(HRTEM) image, a Burgers circuit directly constructed according to an HRTEM image may render a wrong Burgers vector. The HRTEM images of the habit plane(HP) of δ precipitate in an Inconel 718 alloy were re-examined by using different Burgers circuits, as an example. Evidence is found for predicted secondary dislocation associated with a down step. The Burgers vector of the dislocation is 1/6[112]/1/3[001]δ, determined with the Burgers circuit built on the reference of the displacement shift completely lattice(DSCL). It is consistent with both the calculated and the measured result of the major defects in the habit plane. Different Burgers vectors due to different Burgers circuits were explained quantitatively. The present study has a general implication for the determination of the Burgers vectors of secondary interfacial dislocations in other systems.

关键词： Dislocation Burgers vector Burgers circuit Coincidence site lattice (CSL) Displacement shift completely lattice (DSCL) Lattice correspondence

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.

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

Interpretation of the Habit Plane of d Precipitates in Superalloy Inconel 718

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Acta Metallurgica Sinica(English Letters) 2018年第2期31卷 113-126页

作者： wen-Sheng xu Xiao-Peng Yang wen-Zheng Zhang Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University Beijing 100084 China Oxford Instruments Beijing Office Beijing 100085 China

A calculation method based on a combination of Dg parallelism rule, good matching site（GMS） analysis, CSL/DSCL（coincidence site lattice/displacement shift complete lattice） and the O-lattice theory has been applied to interpret the observation of the habit plane（HP） of the d precipitates and the linear defects in the HP in an Inconel 718 superalloy. The small scattering in the HP orientation around an ideal rational plane is interpreted by the existence of a mixture of two types of steps with different heights and inclinations. These steps play a significant role to enhance the degree of matching in the HP. They are associated with secondary dislocations, with Burgers vectors of 1/6 （1 1 2）y/1/3（0 0 1）, and with a direction parallel to a near-invariant line along （110）y. The spacing of the secondary dislocations projected on the terrace plane is around 6.3 nm. The calculated dislocation structure is in good agreement with the observation.

关键词： Good matching site Dislocation Orientation relationship Interfacial structure Coincident site lattice

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

Catalytic asymmetric silicon-carbon bond-forming transformations based on Si–H functionalization

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Science China Chemistry 2023年第6期66卷 1654-1687页

作者： Li Li Wei-Sheng Huang Zheng xu Li-wen xu China Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education Key Laboratory of Organosilicon Material Technology of Zhejiang ProvinceCollege of MaterialChemistry and Chemical EngineeringHangzhou Normal UniversityHangzhou 311121China State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research InstituteLanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

In view of the exciting advancement on silicon–carbon bond-forming transformations achieved in the past decade,this review intends to show a unified illustration of the recent findings on enantioselective Si–H bond functionalization aided by asymmetric ***,this review describes the enantioselective silicon–carbon bond-forming Si–H bond functionalization,focusing on the reactivity and stereoselectivity in catalytic asymmetric hydrosilylation,carbene Si–H insertion,C–H silylation,and Si–C bond-forming cross-coupling reactions that were achieved with high enantioselectivity in the presence of transitionmetal catalyst *** review highlights recent and representative examples of the enantioselective Si–H bond functionalization,discusses the origins of silicon-involving stereoselectivities,and evaluates the substrate scopes and limitations in these catalytic asymmetric Si–H bond functionalization reactions due to the special reactivity of different hydrosilanes.

关键词： Si-H functionalization hydrosilylation C-H silylation carbene Si-H insertion asymmetric catalysis