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Optimal reactions for the synthesis of superheavy nucleus ^(2.0)Hs

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3.& BAO Jingdong1,2.1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education, beijing Normal university, beijing 100875, china 2. Physics Department, beijing Normal university, beijing 100875, china 3. china Institute of Atomic Energy, beijing 102.13. china Key Laboratory of Beam Technology Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China Physics Department Beijing Normal University Beijing 100875 China china Institute of Atomic Energy Beijing 102413 China

The superheavy nucleus 2.0Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 2.8Cm(2.Mg,4n)2.0Hs, 2.4Pu(3.Si,4n)2.0Hs, 2.8U(3.S,4n)2.0Hs and 2.6Ra(48Ca,4n)2.0Hs using a two-parameter Smoluchowski equation. It is found from our results that 2.6Ra(48Ca,4n)2.0Hs and 2.8U(3.S,4n)2.0Hs are two optimal reactions for the synthesis of the superheavy nucleus 2.0Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

SIMULATION　CALCULATION　FOR　CHEMICAL　SPECIATION　OF　LEAD　BY　FEEDBACK　NEURAL　NETWORK

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Chinese Chemical Letters 1996年第3期7卷 265-266页

作者： Hua MO Bo DENG(Department of chemistry, tsinghua university, {2., {3..) TSING HUA UNIV DEPT CHEMBEIJING 100084PEOPLES R CHINA

The chemical speciations of Ph2. in the aqueous solution can becalculated using a Feedback Neural Network. The effects of CO3.2.), random errorand temperature on the simulation results were discussed. The results show... 详细信息

关键词： LEAD OF SPECIATION FEEDBACK CALCULATION BY

Constraints on Cardassian universe from Gamma ray bursts

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1720-1725页

作者： WANG TaiShan1 & LIANG Nan2.1 Department of Physics & Center for Astrophysics,tsinghua university,{2. 100084,china 2.Department of Astronomy,{2. Normal university,{2. 100875,china 1. Department of Physics & Center for Astrophysics Tsinghua University Beijing 100084 China2. Department of Astronomy Beijing Normal University Beijing 100875 China

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the recently derived 42.gamma-ray bursts(GRBs) data calibrated with the method that can avoid the circularity *** results show that GRBs can be an optional observation to constrain the Cardassian *** the GRBs data with the newly de-rived size of baryonic acoustic oscillation peak from the Sloan Digital Sky Survey(SDSS),and the position of the first acoustic peak of the Cosmic Microwave Background radiation(CMB) from Wilkinson Microwave Anisotropy Probe(WMAP),we find Ωm0=0.2.+0.02.0.02.n=0.06+0.07-0.08(1σ) for the original Cardassian model,and Ωm0=0.2.+0.2.-0.02.n=-0.09+0.2.-1.91,β=0.82.2.10-0.62.1σ) for the modified polytropic Cardassian model.

关键词： Cardassian Gamma ray burst Cosmic Microwave Background baryonic acoustic oscillation

A preliminary study on vegetation-erosion dynamics and its applications

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Science china Earth Sciences 2005年第5期48卷 689-700页

作者： WANG Zhaoyin 1,2., WANG Guangqian 1 , LI Changzhi 1 & WANG Feixin 1 1. Department of Hydraulic Engineering, tsinghua university, beijing 100084,{2. 2. International Research and Training Center on Erosion and Sedimentation, beijing 100084,{2. 1. Department of Hydraulic Engineering Tsinghua University 100084 Beijing China 2. International Research and Training Center on Erosion and Sedimentation 100084 Beijing China

Vegetation-erosion dynamics is a new interdisciplinary science, studying the laws of evolution of watershed vegetation under the action of various ecological stresses. Introducing a qualitative expression of ecological stresses in this paper, the present authors establish the cou- pled differential equations for the vegetation-erosion process and derive a theoretical solution. The model is applied to the Anjiagou watershed on the Loess Pateau and the Xiaojiang water- shed and its sub-watersheds on the Yunnan Plateau. The calculated results agree well with the vegetation development processes. Abstracted from the differential equations the so-called vegetation-erosion chart is worked out, with which we can predict the development trend of vegetation under no human stresses. It is demonstrated that the erosion control is important for vegetation development and reforestation must be a long-term strategy. On the Yunnan Plateau with relatively high precipitation and temperature, vegetation can be greatly improved if erosion is controlled. On the dry and cold Loess Pateau suffering from high rate of soil erosion, however, vegetation can effectively control erosion but erosion reduction exhibits low effectiveness on vegetation development. Vegetation in the area is not stable and management is always needed to maintain the vegetation.

关键词： vegetation-erosion dynamics, human activities, coupled differential equations, erosion control, vigor ofvegetation.

Maximal regularity of second order delay equations in Banach spaces

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Science china Mathematics 2010年第1期53卷 51-62页

作者： BU ShangQuan ? & FANG Yi Department of Mathematical Sciences, tsinghua university, beijing 100084,{2. Department of Mathematical Sciences, tsinghua university, beijing 100084,{2. 1. Department of Mathematical Sciences Tsinghua University Beijing 100084 China

We give necessary and sufficient conditions of Lp-maximal regularity(resp.B sp ,q-maximal regularity or F sp ,q-maximal regularity) for the second order delay equations:u″(t)=Au(t) + Gu't + F u t + f(t), t ∈ [0, 2.] with periodic boundary conditions u(0)=u(2.), u′(0)=u′(2.), where A is a closed operator in a Banach space X,F and G are delay operators on Lp([-2., 0];X)(*** ,q([2., 0];X) or Fsp,q([-2., 0;X])).

关键词： maximal regularity second order delay equations Lebesgue-Bochner spaces Besov spaces Triebel-Lizorkin spaces

Bionic Design and Finite Element Analysis of Elbow in Ice Transportation Cooling System

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Journal of Bionic Engineering 2010年第3期7卷 301-306页

作者： Dejun Miao~(1,2., Xiuhua Sui~3. Linjing Xiao~3.1. Key Laboratory of Mine Hazard Prevention and Control (Ministry of Education, china), Shandong university of Science and Technology, Qingdao 2.6510, P. R. china 2. School of Architecture, tsinghua university, beijing 100084, P. R. china 3. College of Mechanical and Electronic Engineering, Shandong university of Science and Technology, Qingdao 2.6510, P. R. china [a] Key Laboratory of Mine Hazard Prevention Control (Ministry of Education China) Shandong University of Science Technology Qingdao 266510 P. R. China [b] School of Architecture Tsinghua University Beijing 100084 P. R. China [c] College of Mechanical Electronic Engineering Shandong University of Science Technology Qingdao 266510 P. R. China

With the increase in mining depth, mine heat harm has appeared to be more prominent. The mine heat harm could be resolvedor reduced by ice refrigeration. Thus, ice transportation through pipeline becomes a critical problem; typically flowresistance occurs in the elbow. In the present study, according to the analysis of the surface morphology of fish scale, abiomimetic functional surface structure for the interior wall of elbow is designed. Based on the theory of liquid-solid two phaseflow, a CFD numerical simulation of ice-water mixture flowing through the elbow is carried out using finite element *** experiments of pressure drop and flow resistance for both bionic and common elbows are conducted to test theeffect of the bionic elbow on flow resistance reduction. It is found that with the increase in the ice mass fraction in the ice-watermixture, the effect of bionic elbow on resistance reduction becomes more obvious.

关键词： bionic elbow two phase flow ice transportation flow resistance reduction pressure loss

Numerical Simulation of Nonlinear Radiation Water Surface Wave Caused by Large-Amplitude Oscillation of A Cylinder

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Communications in Nonlinear Science and Numerical Simulation 1999年第1期4卷 24-28页

作者： Wuzhou HE (Department of Hydraulic Engineering, tsinghua university, beijing 100084,{2.) Department of Hydraulic Engineering Tsinghua University Beijing 100084 China

The BEM combined with the time-stepping scheme is employed in the nonlinear numerical simulation of the development process of radiation wave profile and hydrodynamic force caused by large amplitude oscillating cylinder. To ensure stability and accuracy of the simulation, special consideration is paid on a series of difficulties in numerical modeling, such as the compatibility of free surface and body surface conditions at the intersection point and the open boundary condition problem. Numerical calculation is carried out for some study cases of different shaped cylinders undergoing large amplitude oscillating motions with distinct modes, the results show. some nonlinear phenomena and indicate the feasibility of the numerical approach.

关键词： 2.D water surface wave boundary element method time-stepping scheme

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 2.0096,{3. 2.School of Economics and Management,{2. university,beijing,100084,{3. 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,{2. 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