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A review on the spread of prehistoric agriculture from southern China to mainland Southeast Asia

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Science China Earth Sciences 2020年第5期63卷 615-625页

作者： Yu GAO Guanghui DONG Xiaoyan YANG Fahu CHEN Key Laboratory of Alpine Ecology(LAE) Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Western China’s Environmental Systems College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China

The origins and spread of agriculture was one of the milestones in human *** and how prehistoric agriculture spread to mainland Southeast Asia is highly concerned,which contributed to the formation of modern Austroasiatic in this *** studies mainly focused on the time and route of rice agriculture’s introduction into Southeast Asia while millet agriculture was not paid proper *** we analyze 31214C dating data yielded from charred seeds of rice(Oryza sativa),foxtail millet(Setaria italica)and broomcorn millet(Panicum miliaceum)from 128 archaeological sites in China and mainland Southeast *** result shows that millet farming was introduced to mainland Southeast Asia in the late third millennium BC and rice farming was in the late second millennium *** agriculture of mainland Southeast Asia might originate from three areas,Southwest China,Guangxi-West Guangdong and coastal *** spread route of ancient agriculture in Southwest China is close to the“Southwest Silk Road”recorded in literature,which implies there was possibly a channel of cultural exchanges on the eastern margin of Tibetan Plateau already in the late Neolithic period,laying the foundation for the Southwest Silk Road later.

关键词： Mainland Southeast Asia Southern China Agriculture spread Prehistoric age Southwest Silk Road

Nominal friction coefficient in spread formulas based on lead rolling experiments

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Transactions of Nonferrous Metals Society of China 2015年第8期25卷 2693-2700页

作者：王鸿雨胡玉昆高锋赵德文张殿华东北大学轧制技术及连轧自动化国家重点实验室沈阳110819

Friction coefficients in spread formulas were studied under low width-to-thickness ratio. The effects of all the factors on friction were considered as different roughness of surfaces. After lead rolling experiments in 5 different roughness grades, friction coefficients were obtained. With changing width-to-thickness ratio, reduction rate and ratio of diameter of roller to thickness, all the nominal friction coefficients which can be used in these formulas were calculated. Then, a fitting expression was proposed, comparing with the results measured in 232 times tests, the errors of the nominal friction coefficients calculated by the expression are mostly less than 12%. After a certain times self-learning, the errors are no more than 2%. With the varying nominal friction coefficients, the spread will be predicted more accurately. When the nominal friction coefficient is used to predict the spread under the real working condition, the results calculated are also in agreement with the measured ones, and the errors are less than 2%. This credible reference and solution about how to set the friction coefficient in spread formulas would also be used in practical industrial production.

关键词： spread rolling friction coefficient fitting self-learning

Strip Layer Method for Analysis of the Three-Dimensional Stresses and spread of Large Cylindrical Shell Rolling

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 556-564页

作者： LIU Hongmin CHEN Suwen PENG Yan SUN Jianliang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan University State Key Laboratory of Metastable Materials Science & Technology Yanshan University

As the traditional forging process has many problems such as low efficiency, high consumption of material and energy, large cylindrical shell rolling is introduced. Large cylindrical shell rolling is a typical rotary forming technology, and the upper and lower rolls have different radii and speeds. To quickly predict the three-dimensional stresses and eliminate fishtail defect, an improved strip layer method is developed, in which the asymmetry of the upper and lower rolls, non-uniform deformation and stress, as well as the asymmetrical spread on the end surface are considered. The deformation zone is divided into a certain number of layers and strips along the thickness and width, respectively. The transverse displacement model is constructed by polynomial function, in order to increase the computation speed greatly. From the metal plastic mechanics principle, the three-dimensional stress models are established. The genetic algorithm is used for optimization calculation in an industrial experiment example. The results show that the rolling pressure, the normal stresses, the upper and lower friction stress distributions are not similar with those of a general plate rolling. There are two relative maximum values in rolling pressure distribution. The upper and lower longitudinal friction stresses change direction nearby the upper and lower neutral points, respectively. The fishtail profile of spread on the end surface is predicted satisfactorily. The reduction could be helpful to eliminate fishtail defect. The large cylindrical shell rolling example illustrates the calculation results acquired rapidly are good agreements with the finite element simulation and experimental values of previous study. A highly effective and reliable three-dimensional simulation method is proposed for large cylindrical shell rolling and other asymmetrical rolling.

关键词： large cylindrical shell rolling strip layer method three-dimensional stresses rolling pressure friction stress spread

Continuous compositional spread investigation of SiC-based thin films prepared by MW-ECR plasma enhanced magnetron co-sputtering

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Plasma Science and Technology 2020年第3期22卷 66-70页

作者： Hanghang WANG Liyan ZHANG Wenqi LU Jun XU Key Laboratory of Materials Modification by Laser Ion and Electron BeamsMinistry of EducationSchool of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China School of Chemical Engineering Dalian University of TechnologyDalian 116024People’s Republic of China

A kind of combinatorial material methodology,also known as continuous compositional spread method,was employed to investigate the relationship between the optical band gap and composition of SiC thin films.A wide range of SixCy thin films with different carbon contents have been successfully deposited in a single deposition by carefully arranging the sample position on the substrate *** films were characterized by surface profiler,x-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,fourier transform infrared spectroscopy and Raman *** carbon content y increases linearly from 0.28 to 0.72 while the sample position changed from 85 to 175 mm,the optical band gap changed between 1.27 and 1.99 eV,the maximum value corresponded to the stoichiometric SiC sample at the position of 130 mm,which has the highest Si?C bond density of 11.7×10^22 cm^-*** C poor and C rich SixCy samples with y value less and larger than 0.5 were obtained while samples deviated from the position 130 mm,the optical band gap decreased with the Si?C bond density.

关键词： continuous compositional spread method silicon carbide optical band gap,magnetron sputtering Raman and IR spectra

Energy-spread measurement of triple-pulse electron beams based on the magnetic dispersion principle

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Nuclear Science and Techniques 2017年第4期28卷 8-12页

作者： Yi Wang Qin Li Zhi-Yong Yang Huang Zhang Heng-Song Ding An-Min Yang Min-Hong Wang Key Laboratory of Pulsed Power Institute of Fluid PhysicsChina Academy of Engineering Physics Mianyang 621900China

The method of energy dispersion in magnetic field is used to analyze the energy spread of the triple-pulse electron beam generated by the Dragon-II linear induction accelerator.A sector magnet is applied for energy analysis of the electron beam,with a bending radius of 300 mm and a deflection angle of 90°.For each pulse,the time-resolved and integral images of the electron position at the output port of beam-bending line are recorded by a streak camera and a CCD camera,*** results demonstrate an energy spread of less than ±2.0%for the electron *** cavity voltage waveforms obtained by different detectors are also analyzed for comparison.

关键词： Energy spread Linear induction accelerator Magnetic dispersion

Statistical analysis and model of spread F occurrence in China

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Science China(Technological Sciences) 2010年第6期53卷 1725-1731页

作者： XU Tong1,WU ZhenSen2,HU YanLi1,WU Jian1,SUO YuCheng1 & FENG Jian1 1 National Key Laboratory of Electromagnetic Environment,China Research Institute of Radiowave Propagation,Qingdao 266107,China 2 School of Science,Xidian University,Xi’an 710071,China National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave Propagation Qingdao China School of Science Xidian University Xi’an China

The spread F data obtained over Lanzhou (36.1°N,103.9°E),Chongqing (29.5°N,106.4°E) and Haikou (20.0°N,110.3°E) of China during the period from 1978 to 1997 are used to analyze the occurrence *** statistical results show that the post midnight spread F occurrence is maximum during the summer solstice months of the lower solar activity period,while post sunset spread F is dominant in equinoxes of higher solar activity period over Haikou *** Chongqing and Lanzhou stations,spread F mostly occurs at post midnight and relates negatively with solar *** regression method and Fourier expansion,the preliminary single-station model of spread F occurrence is established and the accuracy of the model is evaluated.

关键词： spread F solar cycle variation seasonal variation empirical model

Management of Control Impacts Based on Maximizing the spread of Influence

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International Journal of Automation and computing 2019年第3期16卷 341-353页

作者： Alexander Tselykh Vladislav Vasilev Larisa Tselykh Institute of Computer Technologies and Information Safety Southern Federal University.Rostov-on-Don 344006.Russia Department of Economics and Business Rostov State University of EconomicsRostov-on-Don 344002.Russia

The choice of fulcrums for control of socio-economic systems represented by direc ted weighted signed graphs is a topic of current *** article proposes a new method for identifying nodes of impact and influential nodes,which will provide a guaranteed positive system response over the growth *** task is posed as an optimization problem to maximize the ratio of the norms of the accumulated increments of the growth vector and the exogenous impact *** algorithm is reduced to solving a quadratic programming problem with nonlinear *** selection of the most effective vertices is based on the cumulative gains of the component projections onto the solution *** examples arc provided to illustrate the effectiveness of the proposed method.

关键词： Directed weighted graphs control impact spread of influence optimization algorithm growth model

Controllable and flexible cellular network for virus cell-to-cell spread

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Chinese Chemical Letters 2019年第6期30卷 1229-1232页

作者： Qiong Yan Cheng Wang Ji Wang Liangjun Pan Zhiling Zhang Key Laboratory of Analytical Chemistry for Biology(Ministry of Education) College of Chemistry and Molecular Sciences Wuhan University

Virus spread is closely related to *** research methods of virus spread do not distinguish cell-to-cell spread from cell-free *** uncertainty of virus induced plaque and virus spread direction makes it difficult to track the spread of virus in ***,the cellular network was fabricated on the basis of PEG modification and soft ***,cell numbers and spatial distributions we re p recisely controlled,e.g.,cellular netwo rks like "WHU" can be ***,a micro-injector was combined with the cellular network for virus spread on the fixed point,in which virus spread direction was limited in one *** results suggested that controllable and flexible cellular network can be constructed on the PEG *** synergia of micro-injector and cellular network provides an advanced tool to investigate virus cell-to-cell spread at the initial infection stage.

关键词： Cellular network Cell-to-cell spread Micro-injector Pseudorabies virus PEG pattern

Research on Flange spread of H-Beamon Universal Mill

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Journal of Iron and Steel Research International 2006年第1期13卷 27-30,39页

作者： XU Xu-dong BAI Jin-lan WANG Bing-xin LIU Xiang-hua WU Di State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The deformation process of H-beams was simulated by explicit dynamic FEM, and the influence of deformation parameters on the spread of rolling piece was obtained. The results show that the flange width, elongation ratio between flange and web and flange thickness are the maior influencing factors on the spread of rolling piece, and the inclination and diameter of vertical roll together with web inner width can also influence to some extent on the spread of rolling piece.

关键词： H-beam FEM spread