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Modeling and simulation of solvent behavior and temperature distribution within long stick propellants with large web thickness undergoing drying

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Defence Technology（防务技术） 2023年第10期28卷 42-55页

作者： Enfa Fu Qianling Liu Yu Luan Yao Zhu weidong He Zhenggang Xiao Key Laboratory of Special Energy Materials Ministry of EducationSchool of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing210094People's Republic of China

Drying is a complicated physical process which involves simultaneous heat and mass transfer in the removal of solvents inside *** drying techniques may result in the formation of a hard skin layer near the surface to block the free access of most solvent through for long stick propellants with large web thickness,which lead to lower drying efficiency and worse drying *** study aims to gain a comprehensive understanding of drying process and clarify the mechanism of the blocked layer near the propellant surface.A new three-dimensional coupled heat and mass transfer(3D-CHMT)model was successfully developed under transient *** drying experiment results show that the 3DCHMT model could be applied to describe the drying process well since the relative error of the content of solvent between simulation and experiment values is only 5.5%.The solvent behavior simulation demonstrates that the mass transfer process can be divided into super-fast(SF)and subsequent minorfast(MF)stages,and the SF stage is vital to the prevention of the blocked layer against the free access for solvent molecules inside propellant *** effective solvent diffusion coefficient(Deff)of the propellant surface initially increases from 3.4×10^(-6)to 5.3×10^(-6)m^(2)/s as the temperature increases,and then decreases to 4.1×10^(-8)m^(2)/s at 60-100 *** value of Deffof surface between 0-1.4 mm has a unique trend of change compared with other regions,and it is much lower than that of the internal at100 min under simulation ***,the temperature of the propellant surface increases rapidly at the SF stage(0-100 min)and then very slowly *** the evolution of Deffand temperature distribution demonstrate that the blocked layer near the propellant surface has been formed in the time period of approximately 0-100 min and its thickness is about 1.4 *** mitigate the formation of blocked layer and improve its drying quality of finial prop

关键词： Stick propellants Drying Large web thickness 3D numerical modeling Heat transfer Solvent behavior

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Characterization of dissolved organic matter in urban sewage using excitation emission matrix fluorescence spectroscopy and parallel factor analysis

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Journal of Environmental Sciences 2010年第11期22卷 1728-1734页

作者： weidong Guo Jing Xu Jiangping Wang Yingrou Wen Jianfu Zhuo Yuchao Yan State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China. Joint Key Laboratory of Coastal Study (XMU & FJIO) Xiamen University Xiamen 361005 China

Wastewater dissolved organic matter （DOM） from different processing stages of a sewage treatment plant in Xiamen was characterized using fluorescence and absorption spectroscopy. Parallel factor analysis modeling of excitation-emission matrix spectra revealed five fluorescent components occurring in sewage DOM： one protein-like （C1）, three humic-like （C2, C4 and C5） and one xenobiotic-like （C3） components. During the aerated grit chamber and primary sedimentation tank stage, there was only a slight decrease in fluorescence intensity and the absorption coefficient at 350 nm （a 350 ）. During the second aeration stage, high concentration of protein-like and short-wavelength-excited humic-like components were significantly degraded accompanied by significant loss of DOC （80%） and a 350 （30%）, indicating that C1 and C2 were the dominant constituents of sewage DOM. As a result, long-wavelength- excited C4 and C5 became the dominant humic-like components and the DOM molecular size inferred from the variation of spectral slope S （300–650 nm） and specific absorption （a 280 /DOC） increased. Combination use of F max of C1 and the ratio of C1/C5, or a 350 may provide a quantitative indication for the relative amount of raw or treated sewage in aquatic environment.

关键词： dissolved organic matter sewage fluorescence EEM parallel factor analysis

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QoS-guaranteed energy saving routing strategy using SDN central control for backbone networks

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The Journal of China Universities of Posts and Telecommunications 2015年第5期22卷 92-100页

作者： Peng Hongyu Wang weidong Wang Chaowei Chen Gang zhang Yinghai College of Electronic Engineering Beijing University of Posts and Telecommunications Key Laboratory of Universal Wireless Communications Beijing University of Posts and Telecommunications

This paper targets on energy saving and considers network responding time for backbone networks. The objective is to find idle links as many as possible which can be put into sleep mode under the situation of quality of service(QoS)-guaranteed. This paper proposes a software defined network(SDN) based routing strategy which is especially aimed at QoS-guaranteed energy saving for backbone networks. Under SDN structure, the topology change of network can be detected directly by network controller. And network can be managed more easily and effectively. Based on the open shortest path first(OSPF) protocol, network topology can be changed as little as possible in our strategy. So, the network reconfiguring time caused by the energy saving strategy will be decreased dramatically. This makes the strategy more feasible. Then the backbone network energy optimizing problem is transformed to the maximum clique problem(MCP). And, this paper designed a routing strategy called backbone networks energy saving strategy(BNESS) for energy saving in backbone networks. Simulation result shows that our proposed strategy can save energy and QoS can be guaranteed.

关键词： Energy efficient networks Backbone Software define

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Impact of Urbanization on Low-Temperature Precipitation in Beijing during 1960–2008

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Advances in Atmospheric Sciences 2014年第1期31卷 48-56页

作者： HAN Zuoqiang YAN Zhongwei LI Zhen LIU weidong WANG Yingchun Key Laboratory of Regional Climate–Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Science Institute of Urban Meteorology China Meteorological Administration

Daily precipitation and temperature records at 13 stations for the period 1960-2008 were analyzed to identify climatic change and possible effects of urbanization on low-temperature precipitation [LTP, precipitation of ≥ 0.1 mm d^-1 occurring under a daily minimum temperature （Tmin） of ≤ 0℃] in the greater Beijing region （B JR）, where a rapid process of urbaniza tion has taken place over the last few decades. The paper provides a climatological overview of LTP in B JR. LTP contributes 61.7% to the total amount of precipitation in B JR in the cold season （November-March）. There is a slight increasing trend [1.22 mm （10 yr）^-1] in the amount of total precipitation for the cold season during 1960-2008. In contrast, the amount of LTP decreases by 0.6 mm （10 yr）^-1. The warming rate of Train in B JR is 0.66℃ （10 yr）^-1. Correspondingly, the frequency of LTP decreases with increasing Tmin by -0.67 times per ℃. The seasonal frequency and amount of LTP in southeast B JR （mostly urban sites） are 17%-20% less than those in the northwestern （rural and montane sites）. The intensity of LTP for the urban sites and northeastern B JR exhibited significant enhancing trends [0.18 and 0.15 mm d^- 1 （10 yr）^- 1, respectively]. The frequency of slight LTP （〈0.2 mm d^-1） significantly decreased throughout B JR [by about -15.74% （10 yr）^-1 in the urban area and northeast B JR], while the contribution of the two heaviest LTP events to total LTP amount significantly increased by 3.2% （10 yr） ^-1.

关键词： urbanization low-temperature precipitation empirical orthogonal function climate change

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In-plane corrugated cosine honeycomb for 1D morphing skin and its application on variable camber wing

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Chinese Journal of Aeronautics 2013年第4期26卷 935-942页

作者： Liu weidong Zhu Hua Zhou Shengqiang Bai Yalei Wang Yuan zhao Chunsheng State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Institute of Science PLA University of Science and Technology

A novel 0-Poisson＇s ratio cosine honeycomb support structure of flexible skin is proposed. Mechanical model of the structure is analyzed with the energy method, finite element method （FEM） and experiments have been performed to validate the theoretical model. The in-plane characteristics of the cosine honeycomb are compared with accordion honeycomb through analytical models and experiments. Finally, the application of the cosine honeycomb on a variable camber wing is studied. Studies show that mechanical model agrees well with results of FEM and experiments. The transverse non-dimensional elastic modulus of the cosine honeycomb increases （decreases） when the wavelength or the wall width increases （decreases）, or when the amplitude decreases （increases）. Compared with accordion honeycomb, the transverse non-dimensional elastic modulus of the cosine honeycomb is smaller, which means the driving force is smaller and the power consumption is less during deformation. In addition, the cosine honeycomb can satisfy the deform- ing requirements of the variable camber wing.

关键词： Cosine honeycomb Flexible skin Mechanical properties Morphing wing Smart structure

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Fabrication of metal-organic framework-based nanofibrous separator via one-pot electrospinning strategy

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Nano Research 2021年第5期14卷 1465-1470页

作者： Congcong Chen weidong zhang He Zhu Bo-Geng Li Yingying Lu Shiping Zhu State Key Lab of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310027China Institute of Pharmaceutical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310027China School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhen518172China Department of Chemical Engineering McMaster UniversityHamiltonOntarioL8S 4L7Canada

Metal-organic framework(MOF)/polymer composites have attracted extensive attention in the recent ***,it still remains challenging to efficiently and effectively fabricate these composite *** this study,we propose a facile one-pot electrospinning strategy for preparation of HKUST-1/polyacrylonitrile(PAN)nanofibrous membranes from a homogeneous stock solution containing HKUST-1 precursors and *** crystallization and polymer solidification occur simultaneously during the electrospinning process,thus avoiding the issues of aggregation and troublesome multistep fabrication of the conventional *** obtained HKUST-1/PAN electrospun membranes show uniform MOF distribution throughout the nanofibers and yield good mechanical *** membranes are used as separators in Li-metal full batteries under harsh testing conditions,using an ultrathin Li-metal anode,a high mass loading cathode,and the HKUST-1/PAN nanofibrous *** results demonstrate significantly improved cycling performance(capacity retention of 83.1%after 200 cycles)under a low negative to positive capacity ratio(N/P ratio of 1.86).The improvement can be attributed to an enhanced wettability of the separator towards electrolyte stemmed from the nanofibrous structure,and a uniform lithium ion flux stabilized by the open metal sites of uniformly distributed HKUST-1 particles in the membrane during cycling.

关键词： one-pot electrospinning strategy metal-organic framework composite nanofibrous membrane battery separator

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Spectral study on feldspar thermoluminescence process

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Science China(Physics,Mechanics & Astronomy) 2008年第3期51卷 225-231页

作者： GONG GeLian LIU ShunSheng XIA Bin SUN weidong HUANG BaoLin Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China Graduate University of the Chinese Academy of Sciences Beijing 100864China

Feldspar thermoluminescence fading phenomena were investigated here by using newly-constructed thermoluminescence spectrometer on the basis of charge-cou-pled detector,and thereafter the discussion and explanation on feldspar TL fading mechanism were presented. The experimental results show that the fading rate of feldspar TL depends on both wavelength and stimulated temperature,and normally the feldspar TL in every region of wavelength and temperature shows different traits,namely the low temperature TL (170℃-190℃) fading at the rate of logarith-mic function and furthermore the TL of different wavelengths fading at approxi-mately the same rate on the condition of 160℃ preheating. While the medium and high temperature TLs (290℃-400℃) do not show much thermal fading,their fading rate at room temperature invariably correlates well with their wavelength,namely the longer TL wavelength,the slower TL fading rate. The thermal instability of traps and the quantum-mechanical tunneling effects can explain the above fading phe-nomena respectively. It is recognized that feldspar TL fading depends on its wave-length,and furthermore new aspects of the solid thermoluminescence process can be displayed by the combination of three-dimensional TL spectral analysis and thermal fading or anomalous fading of TL for feldspar.

关键词： feldspar thermoluminescence spectral anomalous fading thermoluminescence process

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Inequalities for the Radial p-th Mean Bodies

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Wuhan University Journal of Natural Sciences 2012年第4期17卷 281-284页

作者： ZHOU Yanping WANG weidong Department of Mathematics China Three Gorges UniversityYichang 443002HubeiChina

In this paper, we establish an inequality for the volumes of K and its radial p-th mean body R_pK by L_p-dual mixed volume. Further, the Shephard-type problem and a monotonitic inequality of R_pK are shown when p〉0 .

关键词： radial p-th mean body Shephard-type problem monotony

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Spring and autumn living coccolithophores in the Bohai Sea and Yellow Sea,China

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Acta Oceanologica Sinica 2015年第10期34卷 132-146页

作者： JIN Hualong FENG Yuanyuan LI Xiaoqian zhaI weidong SUN Jun College of Marine and Environmental Sciences Tianjin University of Science and Technology Tianjin Key Laboratory of Marine Resources and Chemistry Tianjin University of Science and Technology National Marine Environmental Monitoring Center State Oceanic Administration

The living coccolithophores （LCs） are an important class of calcified taxa of phytoplankton functional groups, and major producers of marine biogenic inorganic carbon, playing an important role in the marine carbon cycle. In this study, we report the two-demensional abundance, composition of LCs and its correlation with the environmental parameters in spring and autumn, in order to understand the ecological role of LCs in the Yellow Sea and the Bohai Sea. In spring, totally 9 taxa belonging to coccolithophyceae were identified using a polarized microscope at the 1 000x magnification. The dominant species were Emiliania huxleyi, Gephyrocapsa oceanica, Helicosphaera carteri, and Calcidiscus leptoporus. The abundance of coccosphores and coccoliths ranged 0-7.72 cells/mL, and 0-216.09 coccoliths/mL, with the average values of 0.21 cells/mL, and 11.36 coccoliths/mL, respectively. The Emiliania huxleyi distribution was similar to Gephyrocapsa oceanica. The highest abundance of coccoliths was observed in the east of Shandong Peninsula in northern Yellow Sea, whereas Helicosphaera carteri distributed more widely. Emiliania huxleyi and Gephyrocapsa oceanica were the two predominant species in LCs with higher abundances. The distribution of LCs was similar to that of coccoliths. In autumn, 14 taxa belonging to coccolithophyceae were identified with dominant species as Emiliania huxleyi, Gephyrocapsa oceanica, Helicosphaera carteri, Calcidiscus leptoporus and Oolithotus fragilis. The abundance of coccosphores and coccoliths ranged 0-24.69 cells/mL, and 0-507.15 coccoliths/mL, with the average values of 1.47 cells/mL, and 55.89 coccoliths/mL, respectively. The highest abundance of coccoliths was located in Qingdao coastal waters and south of the survey area. The distribution of LCs was similar to the coccoliths; in addition, LCs presented large abundance in the east of the central Yellow Sea area.

关键词： living coccolithophores Bohai Sea Yellow Sea spring autumn

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Reworking of the Juvenile Crust in the Late Mesozoic in North Qinling,Central China

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Journal of Earth Science 2022年第3期33卷 623-641页

作者： Ying-Yu Xue Haiyang Liu Zhiyi Wang weidong Sun Fukun Chen Center of Deep Sea Research Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China

The Qinling Orogen resulted from the collision between the North and South China blocks in the *** granitoids,ranging from the Triassic to the Cretaceous,are widely distributed in this orogen,and they provide excellent clues for understanding the crustal evolution and geodynamic evolution of the orogenic *** Triassic belt is mostly located in the South Qinling,whereas the Cretaceous belt is located mostly in the North *** Taibai complex pluton is located at the conjunction of the two *** we present a data set comprising zircon U-Pb dating and elemental and Sr-Nd isotopic geochemistry for Late Mesozoic granite and microgranular enclaves(MME)exposed in the Taibai complex *** granite and MME yield concordant U-Pb zircon ages of 124 to 118 Ma,indicating that they were products of roughly simultaneous magmatism in the Late *** granite rocks are high-K,calc-alkaline,and weakly peraluminous in compositions,and they are characterized by enrichment in large ion lithophile elements(e.g.,Rb,Ba),depletion in high field strength elements(e.g.,Nb,Ta,Zr,Ti),and variable Sr/Y ratios of 7.64 to *** MgO,Cr,and Ni contents imply that the magma(s)were essentially *** the granite and the MME show relative depletion in Sr-Nd isotopic composition(initial ^(87)Sr/^(86)Sr of 0.7044 to 0.7067,initialε_(Nd) values of-3.4 to-2.6),suggesting that the magma(s)originated from juvenile crustal *** Sr-Nd isotopic characteristics are significantly different from those of other Late Mesozoic granitoids exposed elsewhere in the Qinling orogenic belt,which formed from much older and enriched sources and with negligible contributions from mantle or juvenile *** propose a reworking event of the juvenile crust during the Late Mesozoic that was triggered by the tectonic extension and subsequent asthenospheric upwelling that occurred in eastern China.

关键词： Qinling Orogen Mesozoic granite crustal reworking Nd isotope geochemistry

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