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Unramified extensions of quadratic fields

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Progress in Natural Science:Materials International 2008年第3期18卷 323-324页

作者： Wei Li, Dong Yang, Xianke Zhang department of Mathematical Sciences, tsinghua university, beijing 100084, china department of Mathematical Sciences Tsinghua University Beijing 100084 China

Let K be a global quadratic field, then every unramified abelian extension of Kis proved to be absolutely Galois when Kis a number field or under some natural conditions when Kis a function field. The absolute Galois ... 详细信息

关键词： Global quadratic fields Unramified extensions

Non-linear Identification Based on the Method of Gauss Functions

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Communications in Nonlinear Science and Numerical Simulation 1997年第3期2卷 39-44页

作者： Qing ZHANG & Chongde LU (department of Thermal Engineering, tsinghua university ,beijing, 100084) department of Thermal Engineering Tsinghua University Beijing 100084 China

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关键词： identification the method of gauss functions whole optimization

Coacervate Structures of CdI_2 Thin Film Grown during Phase Transformation

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Journal of Materials Science & Technology 1997年第4期13卷 296-298页

作者： Xiaoyan YE and Lili CAO(Dept. of Chemistry, tsinghua university, beijing 100084, china)Jizhong ZHANG and Hengde LI(Dept. of Materials Scieuce & Engineering, tsinghua university, beijing 100084, china) Dept. of Chemistry Tsinghua University Beijing 100084 China Dept. of Materials Science and Engineering Tsinghua University Beijing 100084 China

The microstructure of CdI2 thin film grown during vapor-phase deposition was investigated by scanning electron microscopy (SEM). The thin film deposited on Si crystal consists of numerous sunflower-like aggregates. These aggregates display well self-assembly characteristics. The size of Sunflower-like aggregates is between 12 and 44 μm. Each sunflower-like aggregate is surrounded with many adjacent wings-'petals'. The structure of central region of the 'sunflower' is obviously difFerent from that of the 'petal'. Electron spectroscopy for chemical analysis (ESCA) was employed in determining the chemical valence of the thin film. Self-organization efFect is used to explain the coring growth process of CdI2 thin film

关键词： Thin Coacervate Structures of CdI2 Thin Film Grown during Phase Transformation

A NEW APPROACH TO THE SIMULATION OF UNSTEADY SUBCRITICAL FLOW

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Journal of Hydrodynamics 1995年第3期7卷 84-93页

作者： Mao Ze-yu(department of Hydraulic Engineering, tsinghua university beijing 100084, P. R. china) tsinghua Univ Beijing China

The use of the specified time interval numerical schemes has been popular in applying the method of characteristics to unsteady oped-channel flow problem. Studies and analyses of several variants of those schemes have led to the derivation of a complete set of timeline-interpolation scheme in applying the method of characteristics to Saint-Venant equations. A computer model based upon this scheme has ben successfully developed for predicting free surface unsteady flow, and has been verified by field experiment. Timeline interpolations, where the characteristic lines are projected back before the current time step,demonstrate much less damping than the corresponding spatial interpolation scheme at the same discretization.

关键词： open-channel flow unsteady flow simulation characteristics method,timeline interpolation scheme

An overview of computational photography

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Science china(Information Sciences) 2012年第6期55卷 1229-1248页

作者： SUO JinLi,JI XiangYang & DAI QiongHai department of Automation,tsinghua university,beijing 100084,china 1. department of Automation Tsinghua University Beijing 100084 China

Computational photography is an emerging multidisciplinary *** the last two decades,it has integrated studies across computer vision,computer graphics,signal processing,applied optics and related *** are exploring new ways to break through the limitations of traditional digital imaging for the benefit of photographers,vision and graphics researchers,and image processing *** to much effort in various associated fields,the large variety of issues related to these new methods of photography are described and discussed extensively in this *** give the reader the full picture of the voluminous literature related to computational photography,this paper briefly reviews the wide range of topics in this new field,covering a number of different aspects,including:(i) the various elements of computational imaging systems and new sampling and reconstruction mechanisms;(ii) the different image properties which benefit from computational photography,*** of field,dynamic range;and(iii) the sampling subspaces of visual scenes in the real *** on this systematic review of the previous and ongoing work in this field,we also discuss some open issues and potential new directions in computational *** paper aims to help the reader get to know this new field,including its history,ultimate goals,hot topics,research methodologies,and future directions,and thus build a foundation for further research and related developments.

关键词： computational photography computational imaging plenoptic function light field

Co-adaptability solution to conflict events in construction projects by segmented hierarchical algorithm

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Science china(Technological Sciences) 2008年第7期51卷 932-939页

作者： HOU XueLiang1 & LU Mei2 1 department of Construction Management, tsinghua university, beijing 100084, china 2 College of Management, Xi’an university of Architecture and Technology, Xi’an 710055, china 1. department of Construction Management Tsinghua University Beijing 100084 China 2. College of Management Xi’an University of Architecture and Technology Xi’an 710055 China

In order to seek the co-adaptability solution to conflict events in construction engineering projects, a new method referred to as segmented hierarchical algorithm is proposed in this paper by means of comparing co-adaptability evolution process of conflict events to the stackelberg model. By this new algorithm, local solutions to the first-order transformation of co-adaptability for conflict events can be obtained, based upon which, a global solution to the second-order transformation of co-adaptability for conflict events can also be decided by judging satisfaction degree of local solutions. The research results show that this algorithm can be used not only for obtaining co-adaptability solution to conflict events efficiently, but also for other general decision-making problems with multi-layers and multi-subsidi-aries in project management field.

关键词： conflict co-adaptability segmented hierarchical algorithm

SURFACE MODIFICATION OF CaCO_3 WITH DENDRITIC CARBOXYLIC ACIDS

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Chinese Journal of Polymer Science 2002年第3期20卷 231-235页

作者： Zhao-xia Guo Jian Yu Institute of Polymer Science and Engineering department of Chemical Engineering tsinghua university beijing 100084 china Tsing Hua Univ Dept Chem Engn Inst Polymer Sci & Engn Beijing 100084 Peoples R China

Nanometer calcium carbonate was modified with Frechet type polyether dendrons bearing a COOH group at thefocal point by a wet-coating technique in dichloromethane at room temperature. The interaction between CaCO;and thedendritic modifier was proven by IR and mass spectroscopy of the modified CaCO;after thorough extraction withdichloromethane. The amount of tightly bonded organic modifier was estimated by TGA. It was shown that the amount ofbonded molecules decreased with increasing generation number due to the larger number of branches. Compared tounmodified CaCO;, the modified CaCO;possess different dispersibility in water and in organic solvents.

关键词： calcium carbonate surface modification polyether dendrimer dendritic carboxylic acid

ORDERED WEIGHTED DISTANCE MEASURE

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Journal of Systems Science and Systems Engineering 2008年第4期17卷 432-445页

作者： Zeshui XU~1 Jian CHEN~2 1 School of Economics and Management,Southeast university,Nanjing,Jiangsu 210096,china 2 School of Economics and Management,tsinghua university,beijing,100084,china School of Economics and Management Southeast University Nanjing Jiangsu 210096 China School of Economics and Management Tsinghua University Beijing 100084 China

The aim of this paper is to develop an ordered weighted distance(OWD) measure,which is the generalization of some widely used distance measures,including the normalized Hamming distance, the normalized Euclidean distance,the normalized geometric distance,the max distance,the median distance and the min distance,***,the ordered weighted averaging operator,the generalized ordered weighted aggregation operator,the ordered weighted geometric operator,the averaging operator,the geometric mean operator,the ordered weighted square root operator,the square root operator,the max operator,the median operator and the min operator are also the special cases of the OWD *** methods depending on the input arguments are given to determine the weights associated with the OWD *** prominent characteristic of the OWD measure is that it can relieve(or intensify) the influence of unduly large or unduly small deviations on the aggregation results by assigning them low(or high) *** desirable characteristic makes the OWD measure very suitable to be used in many actual fields,including group decision making,medical diagnosis, data mining,and pattern recognition,***,based on the OWD measure,we develop a group decision making approach,and illustrate it with a numerical example.

关键词： Group decision making ordered weighted distance(OWD) measure aggregation operator

Dark output characteristic of γ-ray irradiated CMOS digital image sensors

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Rare Metals 2002年第1期21卷 79-84页

作者： MENG Xiangti and KANG A iguo Institute of Nuclear Energy Technology, tsinghua university, beijing 100084, china Institute of Nuclear Energy Technology Tsinghua University 北京 100084

The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.

关键词： CMOS digital image sensor gamma radiation dark output characteristic Si