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Comparison and assessment of NDVI time series for seasonal wetland classification

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International Journal of Digital Earth 2018年第11期11卷 1103-1131页

作者： Panpan Xu Zhenguo Niu ping tang State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China

Satellite-based wetland mapping faces challenges due to the high spatial heterogeneity and dynamic characteristics of seasonal *** normalized difference vegetation index(NDVI)time series(NTS)shows great potential in land cover mapping and crop classification,the effectiveness of various NTS with different spatial and temporal resolution has not been evaluated for seasonal wetland *** address this issue,we conducted comparisons of those NTS,including the moderate-resolution imaging spectroradiometer(MODIS)NTS with 500 m resolution,NTS fused with MODIS and Landsat data(MOD_LC8-NTS),and HJ-1 NDVI compositions(HJ-1-NTS)with finer resolution,for wetland classification of Poyang *** showed the following:(1)the NTS with finer resolution was more effective in the classification of seasonal wetlands than that of the MODIS-NTS with 500-m resolution and(2)generally,the HJ-1-NTS performed better than that of the fused NTS,with an overall accuracy of 88.12%for HJ-1-NTS and 83.09%for the MOD_*** work should focus on the construction of satellite image time series oriented to highly dynamic characteristics of seasonal *** study will provide useful guidance for seasonal wetland classification,and benefit the improvements of spatiotemporal fusion models.

关键词： NDVI time series seasonal wetland Poyang Lake satellite image time series

Method for Improving Transverse Wall Thickness Precision of Seamless Steel Tube Based on Tube Rotation

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Journal of Iron and Steel Research International 2015年第10期22卷 924-930页

作者： Yong-zheng JIANG Hua-ping tang State Key Laboratory of High Performance Complex Manufacturing Central South University

The tube rotation method （TRM） refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied. Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling. Results show that the TRM can effectively improve the evenness of thickness distribution. In order to analyze the influence mechanism of the TRM, the finite element method was adopted to simulate the thickness distribution in stretch reduction process. Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal. In addition, the TRM has a correction effect on thickness cusp. All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube.

关键词： seamless tube stretch reducing transverse unevenness tube rotation method

Immobilization of heavy metals in sludge using phosphoric acid and monobasic calcium phosphate

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第3期14卷 177-186页

作者： ping tang Yong-chao ZHOU Zhen-miao XIE College of Environment and Material Engineering Hangzhou Dianzi University College of Civil Engineering and Architecture Zhejiang University

The purpose of this research is to investigate the potential of pre-treatment with phosphoric acid(PA) and monobasic calcium phosphate(MCP) for the stabilization of heavy metals in sludge and its bottom *** tannery sludge samples were collected in Wenzhou,China and heavily contaminated with heavy metals,such as Pb,Cr and so *** samples were pre-treated with PA or *** XRD and TCLP tests were adopted as the evaluating methods to characterize the Pb,Cr,Cu,Zn and Cd immobilization in the pre-treated sludge and its bottom *** results showed that this treatment effectively immobilized Pb and Cd in the sludge,lightly stabilized the metal Cu,and adversely,enhanced the leachability of *** incineration at 900℃,Pb and Cr in the bottom ash of pre-treated sludge were significantly stabilized due to the formation of their highly thermostable phosphates and pyromorphite-like minerals during the incineration ***,an increase of Cu and Zn solubility was observed which might be attributable to the acidification of sludge due to the addition of PA or MCP.

关键词： Tannery sludge Bottom ash Heavy metals Phosphate Stabilization

Polyethylenimine (PEI)g-comb-poly(ethylene glycol)-transferrin(I): Tumor-targeted Vector for Gene Delivery In-vitro

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Chinese Chemical Letters 2006年第1期17卷 113-116页

作者： Gu ping tang Zhi Yu WANG College of Life-Science. ZheJiang University Hangzhou 310028 Institute of Materials Research ＆ Engineering Singapore 3 Research Link 117602 The Second Hospital of Zhejiang University Hangzhou 310006

The work described the synthesis and evaluation of PEI-g-comb-PEG-transferrin as a potential system for gene therapy in vitro. The MW of PEG was 10KDa, and PEI was 2KDa. Its structure was identified by NMR, FT-IR and TGA spectroscopy. MTT assay found that at concentration up to 4000 n mol/L of the polymer, cell viability was over 85%. The bio-character of polymer/DNA complex was characterized by agarose gel electrophoresis, ethidium bromide exclusion and zeta-potential assay. The polymer could retardate DNA at N/P ratio 3.0-3.5 （mol/mol）. The particle size of the polymer/DNA complex was less than 300 nm. Transfection efficiency of the complex was studied in COS7 and NT2 cell lines.

关键词： PEI-g-Comb-PEG transferrin gene therapy transfection efficiency.

CCT and TTT Diagrams to Characterize Crystallization Behavior of Mold Fluxes

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Journal of Iron and Steel Research International 2008年第4期15卷 32-37页

作者： WEN Guang-hua LIU Hui tang ping College of Materials Science and Engineering Chongqing University Chongqing 400044 China

The isothermal and non-isothermal experiments were performed to construct the continuous cooling transformation （CCT） and temperature time transformation （TTT） diagrams of four industrial mold fluxes through visual observations in an experimental apparatus based on the single hot thermocouple technique （SHTT）. The results of the CCT diagrams indicate that ① the crystallization temperature of mold fluxes lowers as the cooling rate increases, ② the mold fluxes have larger critical cooling rate, higher crystallization temperature, and less onset time of crystallization when the basicity increases or the viscosity decreases, ③ the influences of the melting points of the mold fluxes on their crystallization tendency are not significant. Isothermal tests show that the onset time of crystallization decreases at first, and then increases, and finally represents a ＂C＂ shape with increasing isothermal temperature. The TTT diagrams of four industrial mold fluxes were divided into two separate ＂C＂ shape regions. The crystal phase of C20A selected was analyzed by X-ray diffraction, which is cuspidine （Ca4 Si2 O7F2 ） over I 100 ℃ and calcium silicon oxide fluoride （Ca2SiO2F2） below 1 100℃. When compared with the TTT diagram, the CCT diagram can provide a more realistic estimate of the critical cooling rate of the mold fluxes. Thus, both the CCT and TTT diagrams can unambiguously describe the crystallization phenomena of the mold fluxes.

关键词： mold flux CCT TTT critical cooling rate crystallization

Dissymmetric flow phenomenon in a multistrand tundish

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Journal of University of Science and Technology Beijing 2007年第6期14卷 490-494页

作者： Mingmei Zhu Guanghua Wen ping tang Yufeng Wang College of Material Science and Engineering Chongqing University Chongqing 400044 China

The dissymmetric flow phenomenon exists in a symmetric multistrand tundish. It was studied by the physical simulation experiment. The fundamental flow characteristic of dissymmetry was analyzed. The asymmetry of the flow field, the temperature field, and the inclusions distribution without flow-control devices （FCDs） were compared with those with FCDs. It is proved that the asymmetry of the flow and temperature field along the outlets at the long range is more obvious. The symmetric FCDs installation has a slight effect on the dissymmetric temperature field, simultaneously, the symmetry of the average residence time and the fluid flow pattern has improved, and the fluid flow in the tundish has been more reasonable. In case of a symmetric multistrand tundish having a large volume, the influence of the dissymmetric phenomenon should be considered and the flow behaviors in the whole tundish should be studied completely.

关键词： multistrand tundish dissymmetry flow phenomenon physical simulation flow-control devices

Viscosity and Viscosity Estimate Model of Fluoride-Free and Titanium-Bearing Mold Fluxes

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Journal of Iron and Steel Research International 2010年第6期17卷 6-10页

作者： QI Xin WEN Guang-hua tang ping School of Materials Science and Engineering Chongqing University Chongqing 400044 China

The relationship between the binary basicity （CaO/SiO2）,TiO2,Na2O,Li2O,MgO,MnO,B2O3 and viscosity for fluoride-free and titanium-bearing mold fluxes were systematically researched. The rotating cylinder method was employed in the experiment to measure the viscosity of the slag. The results indicate that Li2O, B2O3 and Na2O play major roles in decreasing viscosity, especially Li2O, which is the most effective flux, while MgO and MnO exert little influence on viscosity. Meanwhile, it can be concluded that with increasing TiO2 content, the viscosity of fluoride-free and titanium-bearing mold fluxes increases at first but then falls when the amount of TiO2 is greater than 6.0%. Based on large amounts of experimental statistics of the viscosity of fluoride-free and titanium-bearing mold fluxes, an available model in literature for predicting the mold-slag viscosity was modified. This modified model can be used to predict the viscosity of fluoride-free and titanium-bearing mold fluxes. In fact, the predicted values approximate the observed values with a ±10.6% average deviation. Compared with the classical models,the average deviation is higher and it was found that the modified model can be used to estimate the viscosity of fluoride-free and titanium-bearing mold fluxes.

关键词： viscosity fluoride-free mold flux titanium-bearing mold flux model continuous casting

Synthesis of vinylferrocene and the ligand-exchange reaction between its copolymer and carbon nanotubes

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Frontiers of Chemical Science and Engineering 2014年第2期8卷 171-178页

作者： Ran SHI Hai WANG ping tang Yuezhen BIN Department of Polymer Materials and Engineering Dalian University of Technology Dalian 116024 China Department of Future Industry-Oriented Basic Science and Materials Toyota Technological Institute Tempaku Nagoya 468-8511 Japan

To improve the dispersibility of carbon nanotubes （CNTs）, poly（vinylferrocene-co-styrene）（poly （Vf-co-St））, was grafted onto the surface of CNTs by a ligand-exchange reaction. Poly（Vf-co-St） was obtained by a radical copolymerization reaction using styrene and vinylferrocene as the monomers. The vinylferrocene was synthesized from ferrocene via a Friedel-Crafts acylation. The molecular weight, molecular weight distribution, and amount of Vf in the poly（Vf-co-St） were 1.32 × 104, 1.69 and 17.6% respectively. The degree of grafting of the copolymer onto the CNTs surface was calculated from thermogravimetric analysis and varied from 27.1% to 79.7%. The addition of the poly（Vf-co-St） greatly promoted the dispersibility of the modified CNTs in anhydrous alcohol. The electrical conductivity of compo- sites prepared from the polymer-grafted CNTs and copolymer （acrylonitrile, 1,3-butadiene and styrene, ABS） strongly depended on the degree of grafting. These results show that the amount of polymer grafted onto the surface of CNTs can be controlled and that the electrical properties of composites prepared with these grafted polymers can be tuned.

关键词： vinylferrocene poly (Vf-co-St) CNTs dis-persibility

Applications of self-consistent field theory in polymer systems

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Science China Chemistry 2006年第1期49卷 21-43页

作者： YANG Yuliang QIU Feng tang ping ZHANG Hongdong The Key Laboratory of Molecular Engineering of Polymers of Ministry of Education of China Department of Macromolecular Science Fudan University Shanghai 200433 China The Key Laboratory of Molecular Engineering of Polymers of Ministry of Education of China Department of Macromolecular Science Fudan University Shanghai 200433 China The Key Laboratory of Molecular Engineering of Polymers of Ministry of Education of China Department of Macromolecular Science Fudan University Shanghai 200433 China The Key Laboratory of Molecular Engineering of Polymers of Ministry of Education of China Department of Macromolecular Science Fudan University Shanghai 200433 China

The self-consistent field theory (SCFT) based upon coarse-grained model is especially suitable for investigating thermodynamic equilibrium morphology and the phase diagram of inhomo-geneous polymer systems subjected to phase separation. The advantage of this model is that the details of the chain such as the architecture of the chain and the sequence of blocks can be consid-ered. We present here an overview of SCFT approach and its applications in polymeric systems. In particular, we wish to focus on our group’s achievements in applications of SCFT in such fields: simulation of microphase separation morphologies of multiblock copolymers with a complex molecular architecture, interactions between brush-coated sheets in a polymer matrix, mixtures of flexible poly-mers and small molecular liquid crystals at the interface, shapes of polymer-chain-anchored fluid vesicles, self-assembled morphologies of block copolymers in dilute solution, and so on. Finally, the further developments as well as the perspective applications of SCFT are discussed.

关键词： self-consistent field theory, block copolymer, microphase separation.