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Microstructure, morphology, crystallization and rheological behavior of impact polypropylene copolymer

Science China Chemistry 2012年第5期55卷 698-712页

作者： shang-guan yonggang CHEN Feng ZHENG Qiang Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of EducationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Impact polypropylene copolymer (IPC), named polypropylene catalloy, not only possesses excellent impact property, but also presents good rigidity. Its superior performances result from the complicated composition and microstructure. In the present article, recent progress in the studies on microstructure, morphology, crystallization and rheological behavior of IPC is summarized, and findings of the authors and their collaborators are reported. In general, IPC is divided into three components, i.e., ethylene-propylene random copolymer (EPR), a series of different segment lengths ethylene-propylene copolymer (EbP) and propylene homopolymer. The reasonable macromolecular structures of EbP and a multilayered core-shell model of dispersed phase structure in IPC were proposed, in which the dispersed phase consists of an outer EbP shell, an inner EPR layer and an EbP core. It is found that the annealing at melt-state may lead to an abnormal phase inversion, and the phase inversion disappears when temperature cools down to room temperature. The cause of phase inversion is ascribed to the existence of EbP component, which results in the stronger activity of the dispersed phase. The crystalline structure and morphologic results confirm the formation of β-iPP in IPC. Furthermore, it is found that the ethylene content in IPC and cooling rate of the samples have an important influence on the formation of β-iPP. Based on the crystallization kinetics analyzed by Lauritzen-Hoffman theory, crystallization behavior of different IPC samples is discussed and it is proposed that the dilution effect of ethylene propylene copolymer has a more remarkable influence on surface nucleation than on crystal growth. In addition, annealing at high temperature can result in the changes of chain structure for IPC, and this instability is ascribed to the oxidative degradation and crosslink reaction mainly in iPP component.

关键词： microstructure morphology crystallization behavior rheological property impact polypropylene copolymer

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Recommendation algorithm based on item quality and user rating preferences

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Frontiers of Computer Science 2014年第2期8卷 289-297页

作者： Yuan guan Shimin CAI Mingsheng shang Web Sciences Center School of Computer Science and EngineeringUniversity of Electronic Science and Technology of China Chengdu 611731 China

Recommender systems are one of the most im- portant technologies in e-commerce to help users filter out the overload of information. However, current mainstream recommendation algorithms, such as the collaborative filter- ing CF family, have problems ness. These problems hinder such as scalability and sparse- further developments of rec- ommender systems. We propose a new recommendation al- gorithm based on item quality and user rating preferences, which can significantly decrease the computing complexity. Besides, it is interpretable and works better when the data is sparse. Through extensive experiments on three benchmark data sets, we show that our algorithm achieves higher accu- racy in rating prediction compared with the traditional ap- proaches. Furthermore, the results also demonstrate that the problem of rating prediction depends strongly on item quality and user rating preferences, thus opens new paths for further study.

关键词： recommendation algorithm item quality userrating preferences RMSE

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Development of a soil-plant-atmosphere continuum model (HDS-SPAC) based on hybrid dual-source approach and its verification in wheat field

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Science China(Technological Sciences) 2012年第10期55卷 2671-2685页

作者： YANG YuTing shang SongHao guan Huade State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China School of the Environment&National Centre for Groundwater Research and Training Flinders UniversityAdelaide 5001Australia

HDS-SPAC,a new soil-plant-atmosphere continuum(SPAC) model,is developed for simulating water and heat transfer in *** model adopts a recently proposed hybrid dual source approach for soil evaporation and plant transpiration *** the above-ground part,a layer approach is used to partition available energy and calculate aerodynamic resistances,while a patch approach is used to derive sensible heat and latent heat fluxes from the two sources(soil and vegetation).For the below-ground part,soil water and heat dynamics are described by the mixed form of Richards equation,and the soil heat conductivity equation,*** two parts are coupled through ground heat flux for energy transfer,root-zone water potential-dependent stomatal resistance,and surface soil water potential-dependent evaporation for water *** is calculated from the water potential gradient at soil-atmosphere interface and aerodynamic resistance,and transpiration is determined using a Jarvis-type function linking soil water availability and atmospheric *** other processes,such as canopy interception and deep percolation,are also considered in the HDS-SPAC *** hybrid dual-source approach allows HDS-SPAC to simulate heat and water transfer in an ecosystem with a large range of vegetation cover change temporally or *** model was tested with observations at a wheat field in North China Plain over a time of three months covering both wet and dry *** fractional crop covers change from 30% to over 90%.The results indicated that the HDS-SPAC model can estimate actual evaporation and transpiration partitioning and soil water content and temperature over the whole range of tested vegetation coverage.

关键词： soil-plant-atmosphere continuum energy budget soil water dynamics dual-source model vegetation characteristics

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ATR-FTIR and XPS study on the structure of complexes formed upon the adsorption of simple organic acids on aluminum hydroxide

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Journal of Environmental Sciences 2007年第4期19卷 438-443页

作者： guan Xiao-hong CHEN guang-hao shang Chii School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China. Department of Civil Engineering Hong Kong University of Science and Technology Hong Kong China

Information on the binding of organic ligands to metal （hydr）oxide surfaces is useful for understanding the adsorption behaviour of natural organic matter on metal （hydr）oxide. In this study, benzoate and salicylate were employed as the model organic ligands and aluminum hydroxide as the metal hydroxide. The attenuated total reflectance Fourier transform infrared （ATR-FTIR） spectra revealed that the ligands benzoate and salicylate do coordinate directly with the surface of hydrous aluminum hydroxide, thereby forming innersphere surface complexes. It is concluded that when the initial pH is acidic or neutral, monodentate and bridging complexes are to be formed between benzoate and aluminum hydroxide while bridging complexes predominate when the initial pH is alkalic. Monodentate and bridging complexes can be formed at pH 5 while precipitate and bridging complexes are formed at pH 7 when salicylate anions are adsorbed on aluminum hydroxide. The X-ray photoelectron （XP） spectra demonstrated the variation of C 1 s binding energy in the salicyate and phenolic groups before and after adsorption. It implied that the benzoate ligands are adsorbed through the complexation between carboxylate moieties and the aluminum hydroxide surface, while both carboxylate group and phenolic group are involved in the complexation reaction when salicylate is adsorbed onto aluminum hydroxide. The information offered by the XPS confirmed the findings obtained with ATR-FTIR.

关键词： adsorption aluminum hydroxide benzoic acid complexation natural organic matter salicylic acid

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Adsorption behavior of condensed phosphate on aluminum hydroxide

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Journal of Environmental Sciences 2007年第3期19卷 312-318页

作者： guan Xiao-hong CHEN guang-hao shang Chii School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China Department of Civil Engineering Hong Kong University of Science and Technology Hong Kong China

Sodium pyrophosphate （pyro-P, Na4P2OT）, sodium tripolyphosphate （tripoly-P, Na3P3O10）, and sodium hexametaphosphate （meta-P, （NaPO3）6） were selected as the model compounds of condensed phosphate to investigate the adsorption behavior of condensed phosphate on aluminum hydroxide. The adsorption was found to be endothermic and divisible into two stages：（1） fast adsorption within 1 h; and （2） slow adsorption between 1 and 24 h. The modified Freundlich model simulated the fast adsorption stage well; the slow adsorption stage was described well by the first-order kinetics. The activation energies of pyro-P, tripoly-P, and meta-P adsorption on aluminum hydroxide were determined to be 20.2, 22.8 and 10.9 kJ/mol P adsorbed, respectively, in the fast adsorption stage and to be 66.3, 53.5 and 72.5 kJ/mol P adsorbed, respectively, in the slow adsorption stage. The adsorption increased the negative charge of the aluminum hydroxide surface. Transmission electron microscopy and energy dispersive X-ray analysis analyses provided evidence that the adsorption was not uniform on the surface and that the small crystals contributed more to the fast adsorption than the normal sites did. The results from X-ray fluorescence spectrometry and X-ray photoelectron spectroscopy tests also revealed the uneven adsorption of condensed phosphate as a function of the penetration depth. More condensed phosphates were adsorbed on the outer surface of aluminum hydroxide than in its inner parts.

关键词： activation energy aluminum hydroxide condensed phosphate eutrophication surface charge

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The annual mean sketches and climatological variability of the volume and heat transports through the inter-basin passages:A study based on 1 400-year spin up of MOM4p1

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Acta Oceanologica Sinica 2014年第9期33卷 12-24页

作者： ZHU Yaohua WEI Zexun WANG yonggang guan Yuping WANG Xinyi Key Laboratory of Marine Science and Numerical Modeling First Institute of Oceanography State Oceanic Administration State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences

The annual mean volume and heat transport sketches through the inter-basin passages and transoceanic sections have been constructed based on 1400-year spin up results of the MOM4p 1. The spin up starts from a state of rest, driven by the monthly climatological mean force from the NOAAWorld Ocean Atlas （1994）. The volume transport sketch reveals the northward transport throughout the Pacific and southward transport at all latitudes in the Atlantic. The annual mean strength of the Pacific-Arctic-Atlantic through flow is 0.63x106 m3/s in the Bering Strait. The majority of the northward volume transport in the southern Pacific turns into the Indonesian through flow （ITF） and joins the Indian Ocean equatorial current, which subse- quently flows out southward from the Mozambique Channel, with its majority superimposed on the Ant- arctic Circumpolar Current （ACC）. This anti-cyclonic circulation around Australia has a strength of 11 x 106 ms /s according to the model-produced result. The atmospheric fresh water transport, known as P-E^R （pre- cipitation minus evaporation plus runoff）, constructs a complement to the horizontal volume transport of the ocean. The annual mean heat transport sketch exhibits a northward heat transport in the Atlantic and poleward heat transport in the global ocean. The surface heat flux acts as a complement to the horizontal heat transport of the ocean. The climatological volume transports describe the most important features through the inter-basin passages and in the associated basins, including： the positive P-E＋R in the Arctic substantially strengthening the East Greenland Current in summer; semiannual variability of the volume transport in the Drake Passage and the southern Atlantic-Indian Ocean passage; and annual transport vari- ability of the ITF intensifying in the boreal summer. The climatological heat transports show heat storage in July and heat deficit in January in the Arctic; heat storage in January and heat deficit in July in the

关键词： volume transport heat transport global ocean circulation inter-basin passages climatologicalvariability

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Gold mineralization age of the Anjiayingzi gold deposit in Chifeng County, Inner Mongolia and implications for Mesozoic metallogenic explosion in North China

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Science China Earth Sciences 2004年第2期47卷 115-121页

作者： LI yonggang ZHAI Mingguo YANG Jinhui MIAO Laicheng guan Hong Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The Anjiayingzi gold deposit in Chifeng County, Inner Mongolia is located in the central part of the gold mineralization belt of the northern margin of the North China Craton (NCC), and is adjacent to the Paleozoic Inner Mongolia-Da Hinggan Mountains orogenic belt in the north. The Chifeng-Kaiyuan fault, which separates the NCC from this orogenic belt, is considered to be a regional ore-controlling structure. The Anjiayingzi gold deposit is a mediate-size quartz lode-gold deposit and is hosted by the Anjiayingzi quartz monzonite that was emplaced into the basement composed of early Precambrian gneisses. Rhyolitic and porphyritic dikes are generally associated with the gold mineralization. Zircon U-Pb analyses suggest that the Anjia- yingzi granite was emplaced from 132 Ma to 138 Ma, while the rhyolitic dikes that occupy the same fracture system as the gold-bearing quartz veins and locally crosscut the gold lodes crystallized from 125 Ma to 127 Ma. These results constrain the mineralization age between 126 Ma and 132 Ma, early Cretaceous time for the Anjiayingzi gold deposit. This mineralization age is consistent with that of the gold deposits in other major gold-bearing areas of the NCC, such as the Jiaodong Peninsula and the Xiaoqinling Mountain, and specially is roughly coeval with the geodynamic reversion of the NCC in Mesozoic. This coincidence probably indicates that the gold deposits in the NCC, including the Anjiayingzi deposit, formed in a similar geodynamic setting characterized by large-scale thinning of the lithosphere underlying the NCC.

关键词： Anjiayingzi, gold deposit, granite, zircon, geochronology, explosive metallogeny.

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Interbasin exchanges and their roles in global ocean circulation:A study based on 1 400 years' spin up of MOM4p1

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Acta Oceanologica Sinica 2014年第1期33卷 11-23页

作者： ZHU Yaohua WEI Zexun FANG Guohong WANG yonggang guan Yuping Key Laboratory of Marine Science and Numerical Modeling First Institute of Oceanography State Oceanic Administration State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences

A global prognostic model based on MOM4p1,which is a primitive equation nonBoussinesq numerical model,has been integrated with 1 400 years from the state of rest based on the realistic topography to study the long-term pattern of combined wind-driven and thermodynamically-driven general *** model is driven by monthly climatological mean forces and includes 192×189 horizontal grids and 31 pressure-based vertical *** main objective is to investigate the mass and heat transports at interbasin passages and their compensations and roles in the global ocean circulation under equilibrium state of long-term spin *** kinetic energy analysis divides the spin up process into three stages：the quasi-stable state of wind driven current,the growing phase of thermodynamical circulation and the equilibrium state of thermohaline *** is essential to spin up over a thousand years in order to reach the thermohaline equilibrium state from a state of *** Arctic Throughflow from the Bering Strait to the Greenland Sea and the Indonesian Throughflow（ITF） are captured and examined with their compensations and existing *** reveals that the slope structures of sea surface height are the dynamical driving mechanism of the Pacific-Arctic-Atlantic throughflow and *** analysis denotes,in spite of O（1.4×106m3/s） of the southward volume transport in the northern Atlantic,that there is still O（1 PW） of heat transported northward since the northward currents in the upper layer carry much higher temperature water than the southward flowing northern Atlantic deep water（NADW）.Meridional volume and heat transports are focused on the contributions to NADW renewals and Atlantic meridional overturning circulation（AMOC）.Quantitative descriptions of the interbasin exchanges are explained by meridional compensations and supported by previous observations and numerical modeling *** indicates that the volume and heat exchanges on the interbasin passa

关键词： numerical modeling global ocean interbasin exchange meridional transport meridional over-turning circulation

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Structure and Dynamics of Energy Materials from Machine Learning Simulations:A Topical Review

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Chinese Journal of Chemistry 2021年第11期39卷 3144-3154页

作者： Shu-Hui guan Cheng shang Zhi-Pan Liu shanghai Academy of Agricultural Sciences Shanghai201403 China Collaborative Innovation Center of Chemistry for Energy Material Shanghai Key Laboratory of molecular Catalysis and Innovative MaterialsKey Laboratory of Computational Physical ScienceDepartment of ChemistryFudan UniversityShanghai200438 China

Energy materials featuring the capability to store and release chemical energy reversibly involve generally complex geometrical structures with multiple *** has been a great challenge to establish the quantitative relationship between the structure of materials and their dynamic physicochemical *** recent years,machine learning(ML)technique has demonstrated its great power in accelerating the research on energy *** topical review introduces the key ingredients and typical applications of ML to energy *** mainly focus on the ML based atomic simulation via ML potentials in different architectures/implementations,including high dimensional neural networks(HDNN),Gaussian approximation potential(GAP),moment tensor potentials(MTP)and stochastic surface walking global optimization with global neural network potential(SSW-NN)*** cases studies,namely,Si,LiC and LiTiO systems,are presented to demonstrate the ability of ML simulation in assessing the thermodynamics and kinetics of complex material *** highlight that the SSW-NN method provides an automated solution for global potential energy surface data collection,ML potential construction and ML simulation,which boosts the current ability for large-scale atomic simulation and thus holds the great promise for fast property evaluation and material discovery.

关键词： Machine learning Materials science Atomic simulation Thermodynamics Kinetics

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Dynamic data auditing scheme for big data storage

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Frontiers of Computer Science 2020年第1期14卷 219-229页

作者： Xingyue CHEN Tao shang Feng ZHANG Jianwei LIU Zhenyu guan School of Electronic and Information Engineering Beihang UniversityBeijing 100083China School of Cyber Science and Technology Beihang UniversityBeijing 100083China

When users store data in big data platforms,the integrity of outsourced data is a major concern for data owners due to the lack of direct control over the ***,the existing remote data auditing schemes for big data platforms are only applicable to static *** order to verify the integrity of dynamic data in a Hadoop big data platform,we presents a dynamic auditing scheme meeting the special requirement of ***,a new data structure,namely Data Block Index Table,is designed to support dynamic data operations on HDFS(Hadoop distributed file system),including appending,inserting,deleting,and *** combined with the MapReduce framework,a dynamic auditing algorithm is designed to audit the data on HDFS *** shows that the proposed scheme is secure enough to resist forge attack,replace attack and replay attack on big data *** is also efficient in both computation and communication.

关键词： big data data security remote data auditing dynamic update privacy protection

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