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PIXE and INAA studies on ancient potteries from Guangfulin relics in Shanghai

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Progress in Natural Science:Materials International 2007年第11期17卷 1348-1356页

作者： Lin Jiawei1, Cheng Huansheng1, Zhang Zhengquan1, Zhang Bin1, Feng Songlin2, Song Jian3. Gao Menghe4 and Zhu Dan1(1. applied Ion Beam Physics Laboratory, Key Laboratory of the Ministry of Education, institute of Modern Physics, Fudan university, Shanghai 20043.,{3. 2. Key Laboratory of Nuclear Analytical Techniques, institute of High Energy Physics, Beijing 10003.,{3. 3. Shanghai Museum, Shanghai 200003.{3. 4. Department of Cultural Heritage and Museology, Fudan university, Shanghai 20043.,{3.) applied Ion Beam Physics Laboratory Key Laboratory of the Ministry of Education Institute of Modern Physics Fudan University Shanghai 200433 China Key Laboratory of Nuclear Analytical Techniques Institute of High Energy Physics Beijing 100039 China Shanghai Museum Shanghai 200003 China Department of Cultural Heritage and Museology Fudan University Shanghai 200433 China

This paper reports the study of ancient potteries unearthed from the Guangfulin site in Shanghai. From the external features of these potteries, archeologists can classify them into two different cultural types: Liangzhu culture (local culture) and a new culture which might be derived elsewhere, but they can not recognize whether they were produced in the same place. Proton induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA) were used to measure the chemical compositions of the samples and the results were analyzed using multivariate statistics. We found that the two methods can complement each other and their database can be mutually referenced in the study of ancient potteries. Experimental results show that the compositions of the potteries from the two cultural types are different, which means that the materials for ancient potteries of new culture originate from elsewhere. This supports the archaeologists’ speculation that a group of ancient people migrated to Shanghai from some other places 4000 years ago.

关键词： PIXE INAA factor analysis Guangfulin ancient pottery

LARGE-EDDY SIMULATION OF THREE-DIMENSIONAL VORTICAL STRUCTURES FOR AN IMPINGING TRANSVERSE JET IN THE NEAR REGION

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Journal of Hydrodynamics 2007年第3期19卷 314-321页

作者： FAN Jing-yu ZHANG Yan WANG Dao-zeng Shanghai institute of applied mathematics and {3. Shanghai University Shanghai 200072 China Key Laboratory of Advanced Display and System Applications （Shanghai university） Ministry of Education and SMIT Center Shanghai University Shanghai 200072 China Department of applied mechanics Chalmers University of Technology SE-412 96 Gothenburg Sweden Shanghai institute of applied mathematics and {3. Shanghai University Shanghai 200072 China

The three-dimensional vortical structures for an impinging transverse jet in the near region were numerically investigated by means of Large-Eddy Simulation （LES）. The LES results reproduced the skewed jet shear layer vortices close to the jet nozzle and the scarf vortex in the near-wall zone in good agreement with the experimental observations. Different vortical modes in the skewed jet shear layer close to the jet nozzle were identified depending upon the velocity ratio between jet and crossflow, namely changing from an approximately axisymmetric mode to a helical one with the velocity ratios varying from 20 to 8. Moreover, the scarf vortex wrapped around the impinging jet in the near-wall zone showed distinct asymmetry with regard to its bilateral spiral legs within the near region. And the entrainment of the ambient crossflow fluids by the scarf vortex in the near-wall zone was appreciably influenced by its asymmetry and in a large part occurred on the surface of the spiral roller structures in the course of spreading downstream.

关键词： Large-Eddy Simulation (LES) impinging jet crossflow vortical structure entrainment

Convergence analysis of the adaptive finite element method with the red-green refinement

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Science china mathematics 2010年第2期53卷 499-512页

作者： ZHAO XuYing 1, 3., HU Jun 2,? & SHI ZhongCi 1 1 State Key Laboratory of Scientific and Engineering Computing, institute of Computational mathematics and Scientific/Engineering Computing, Academy of mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190,{3. 2 Key Laboratory of mathematics and applied mathematics (Peking university), Ministry of Education and School of Mathematical Sciences, Peking university, Beijing 100871,{3. 3.Graduate university of Chinese Academy of Sciences, Beijing 100190,{3. 1. State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100190 China2. Key Laboratory of Mathematics and Applied Mathematics (Peking University) Ministry of Education and School of Mathematical Sciences Peking University Beijing 100871 China

In this paper, we analyze the convergence of the adaptive conforming P 1 element method with the red-green refinement. Since the mesh after refining is not nested into the one before, the Galerkin-orthogonality does not hold for this case. To overcome such a difficulty, we prove some quasi-orthogonality instead under some mild condition on the initial mesh (Condition A). Consequently, we show convergence of the adaptive method by establishing the reduction of some total error. To weaken the condition on the initial mesh, we propose a modified red-green refinement and prove the convergence of the associated adaptive method under a much weaker condition on the initial mesh (Condition B).

关键词： red-green refinement adaptive finite element method convergence non-nested local refinement

EXPERIMENTAL STUDY ON THE VORTEX FORMATION AND ENTRAINMENT CHARACTERISTICS FOR A ROUND TRANSVERSE JET IN SHALLOW WATER

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Journal of Hydrodynamics 2009年第3期21卷 386-393页

作者： FAN Jing-yu ZHANG Yan WANG Dao-zeng Shanghai institute of applied mathematics and {3. Shanghai University Shanghai 200072 China Key Laboratory of Advanced Display and System Applications Ministry of Education and SMIT Center School of Mechatronics Engineering and Automation Shanghai University Shanghai 200072 China

The vortex formation and entrainment characteristics for a round transverse jet in shallow water were experimentally investigated by means of a combination of LIF flow visualization and PIV measurement. A scarf vortex wrapped around the main body of the jet is formed in the near-wall region due to the interaction between the resulting wall jet and sufficiently shallow crossflow, with some more or less unsteady flow properties and with spreading ranges as functions of both the velocity ratio and the water depth within the near field. The entrainment of the ambient crossflow fluid into the jet main body is closely associated with the time-evolving features of the shear layer between the jet and surrounding fluid as well as the induced vortical structures near the wall. In the case of slight impingement upon the wall, the interaction between the jet shear layer and the weak, unstable scarf vortex gives rise to an appreciable local entrainment enhancement, confined in the near-wall region in the vicinity of the stagnation point. While in the case of intense impingement upon the wall, the well-organized and stable scarf vortex gives rise to a greatly enhanced entrainment and a greatly increased lateral spreading rate nearly throughout the overall near field as compared to the conventional wall jet. In addition, the entrainment of the ambient crossflow fluid by the scarf vortex in this case occurs largely on the surface of the unique spiral roller structure by itself due to the presence of smaller and unorganized eddies, and accordingly the scarf vortex is likely to keep its spiral roller structure steadily to a relatively great downstream distance within the near field.

关键词： transverse jet shallow water vortex formation entrainment PIV measurement

EXPERIMENTAL AND NUMERICAL INVESTIGATION OF FREE SURFACE VORTEX

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Journal of Hydrodynamics 2008年第4期20卷 485-491页

作者： LI Hai-feng CHEN Hong-xun MA Zheng ZHOU Yi Shanghai institute of applied mathematics and {3. Shanghai University Shanghai 200072 China china Ship Scientific Research Center Wuxi 214082 China

An experimental model was set up to investigate the formation and evolution of the free surface vortex. A Particle Image Velocimetry （PIV） was used to measure the free surface vortex flow field at different development stages. Flow visualization was used to locate the vortex position and find its structure. Empirical formulas about the critical submergence and the whole field structure were obtained. It is found that the tangential velocity distribution is similar to that of the Rankine vortex and the radial velocity changes little in the vortex functional scope. Vortex starts from the free surface and gradually intensifies to air entrainment vortex. The vortex core moves during the formation and evolution of the free surface vortex. Based on the experimental model, the vortex position and structure were predicted by numerical simulation combined with a vortex model and compared with that of the experiments, which shows satisfactory agreement.

关键词： free surface vortex Particle Image Velocimetry (PIV) numerical simulation rankine vortex

Parameter identification theory of a complex model based on global optimization method

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Science china(Physics,mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3.1 College of Automotive Engineering, South china university of Technology, Guangzhou 510640, china 2 Beijing Research {3. of Mechanical and Electrical Technology, Beijing 100083. china 3.Department of Engineering mechanics, Tsinghua university, Beijing 100084, china 1. College of Automotive Engineering South China University of Technology Guangzhou 510640 China 2. Beijing Research institute of Mechanical and Electrical Technology Beijing 100083 China 3. Department of Engineering mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

Studies on the analytical potential energy function of diatomic molecular ion XY^+ using variational method

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Science china(Physics,mechanics & Astronomy) 2004年第2期47卷 154-164页

作者： LIU Guoyue1,3. SUN Weiguo1,2 & FENG Hao1 1. institute of Physics, Sichuan university, Chengdu 610065, china 2. College of Chemical Engineering, Sichuan university, Chengdu 610065, china 3. Mianyang Teacher抯 College, Mianyang 621000, china Correspondence should be addressed to Sun Weiguo (e-mail: weiguosun@*** or guoyueliu@ ***) 1. institute of Physics Sichuan University 610065 Chengdu China 2. Mianyang Teacher's College 621000 Mianyang China 3. College of Chemical Engineering Sichuan University 610065 Chengdu China

A new analytical potential energy function for diatomic molecular ion XY+ is proposed based on the energy consistent method (ECM). The Coulomb potential included in the new ionic potential contains multipole corrections, converges quickly and is variationally, changeable. The new potential and the ECM are applied to variationally studying the potential energies of eight electronic states of several diatomic molecular ions: the A2π state of CO+, the X2∑ g + state of Li 2 + , the X2∑ g + state of He 2 + , the 12∏u state of Na 2 + , the A2∏u state of N 2 + , the X1∑+ state of KrH+, the X2∑+ state of SiO+ and the A2π state of SO+ ion. The present results agree excellently with the experiment-based Rydberg-Klein-Rees (RKR) potentials, and are superior to the commonly used Huxley-Murrell-Sorbie (HMS) analytical potentials, and are better in some cases than some quantum mechanicalab initio potentials in the ionic asymptotic and dissociation regions.

关键词： potential energy, diatomic ion, electronic state, variational method.

Comparison of the influence factors on NDVI for CCD camera and WFI imager on CBERS-02

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Science china(Technological Sciences) 2005年第S2期48卷 100-115页

作者： YU Tao1,3. LI Xiaoying1,2,3. ZHANG Yong1,2,3. ZHAO Feng1,2,3. GU Xingfa1,3.4, ZHU Li1,2,3. WANG Pengxin5 & MIN Xiangjun6 1. State Key Laboratory of Remote Sensing Science institute of Remote Sensing Application, CAS, Bei- jing 100101, china 2. Graduate university of Chinese Academy of Sciences, Beijing 10003., china 3. The Center for National Spaceborne Demonstration, Beijing 100101, china 4. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 5. College of Information and Electrical Engineering, china Agricultural university, Beijing 100083. china 6. china Center for Resource Satellite Data and Application, Beijing 10083., china 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Application CAS 100101 Beijing China 2. The Center for National Spaceborne Demonstration 100101 Beijing China 3. Graduate university of Chinese Academy of Sciences 100039 Beijing China 4. Institut National de la Recherche Agronomique Climat Sol Environnent 84914 Avignon France 5. College of Information and Electrical Engineering China Agricultural University 100083 Beijing China 6. china Center for Resource Satellite Data and Application 100830 Beijing China

CCD and WFI are payloads in the visible light and near infrared bands on CBERS satellites and they have not been applied widely, especially WFI. This article mainly probes into the potential of these two sensors’ application in the vegetation monitoring and analyses the influences of radiometric calibration, atmosphere conditions and sun-observing geometry, etc. on NDVI obtained from these two sensors respectively. In addition it analyses the effect of the spectral response difference of red and near infrared spectral bands in CCD and WFI sensors on NDVI. Results indicate that radiometric calibration is the most important factor on NDVI, which cannot be applied to vegetation monitoring without radiometric calibration. Results also demonstrate that near surface NDVI is different greatly from that of TOA which change with atmosphere conditions. The study shows that NDVI is also affected by the non-lambertian character of surface and the change of the atmospheric path with the observing geometry. And NDVI of WFI is higher than that of CCD. They are very different because of their spectral difference, but they have a good linear relevant relationship.

关键词： CCD WFI NDVI LAI.

FORMATION AND INFLUENCING FACTORS OF FREE SURFACE VORTEX IN A BARREL WITH A CENTRAL ORIFICE AT BOTTOM

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Journal of Hydrodynamics 2009年第2期21卷 238-244页

Based on the Navier-Stokes equations with considering the effect of the Coriolis force, the finite volume method was employed to discretize the governing equations, the SIMPLE method was adopted to solve the discretized equations, and the flow field in a barrel with an outlet at the center of the bottom was simulated. The numerical results agree well with the experimental data. From the Lagrangian, the relations among the acceleration, the Coriolis force and the viscosity force were analyzed. The results show that the Coriolis force is the major factor that causes the formation of the vortex. The flow fields in the flume under different incoming flow conditions were numerically simulated using the software Fluent. The numerical simulations show good agreement with the experiments for the shape and position of the vortex.

关键词： free surface vortex Coriolis force numerical simulation