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Spatial pattern of impervious surfaces and their impacts on land surface temperature in Beijing,China

Journal of Environmental Sciences 2007年第2期19卷 250-256页

作者： XIAO Rong-bo OUYANG zhi-yun ZHENG Hua LI Wei-feng SCHIENke Erich W wang Xiao-ke State key Lab of Urban and Regional Ecology Environmental Sciences Chinese Academy of Sciences Belting 100085 China Department of Science and Technology Studies Rensselaer Polytechnic Institute Troy NY 12180 USA

Land surface temperature （LST）, which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces （IS） spatial patterns have on LST in Beijing, China. A classification and regression tree model （CART） was adopted to estimate IS as a continuous variable using Landsat images from two seasons combined with QuickBird. LST was retrieved from the Landsat Thematic Mapper （TM） image to examine the relationships between IS and LST. The results revealed that CART was capable of consistently predicting LST with acceptable accuracy （correlation coefficient of 0.94 and the average error of 8.59%）. Spatial patterns of IS exhibited changing gradients across the various urban-rural transects, with LST values showing a concentric shape that increased as you moved from the outskirts towards the downtown areas. Transect analysis also indicated that the changes in both IS and LST patterns were similar at various resolution levels, which suggests a distinct linear relationship between them. Results of correlation analysis further showed that IS tended to be positively correlated with LST, and that the correlation coefficients increased from 0.807 to 0.925 with increases in IS pixel size. The findings identified in this study provide a theoretical basis for improving urban planning efforts to lessen urban temperatures and thus dampen urban heat island effects.

关键词： urban heat islands urban land cover normalized difference vegetation index (NDVI) climate mitigation regression tree

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Effect of CO_2 and H_2O on gasification dissolution and deep reaction of coke

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International Journal of Minerals,Metallurgy and Materials 2018年第12期25卷 1402-1411页

作者： zhi-yu Chang Ping wang Jian-liang Zhang ke-xin Jiao Yue-qiang Zhang Zheng-jian Liu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Metallurgical Engineering Anhui University of Technology The third ironworks Ma'anshan Iron & Steel Co. Ltd

To more comprehensively analyze the effect of CO_2 and H_2O on the gasification dissolution reaction and deep reaction of coke, the reactions of coke with CO_2 and H_2O using high temperature gas–solid reaction apparatus over the range of 950–1250°C were studied, and the thermodynamic and kinetic analyses were also performed. The results show that the average reaction rate of coke with H_2O is about 1.3–6.5 times that with CO_2 in the experimental temperature range. At the same temperature, the endothermic effect of coke with H_2O is less than that with CO_2. As the pressure increases, the gasification dissolution reaction of coke shifts to the high-temperature zone. The use of hydrogen-rich fuels is conducive to decreasing the energy consumed inside the blast furnace, and a corresponding high-pressure operation will help to suppress the gasification dissolution reaction of coke and reduce its deterioration. The interfacial chemical reaction is the main rate-limiting step over the experimental temperature range. The activation energies of the reaction of coke with CO_2 and H_2O are 169.23 kJ ·mol-1 and 87.13 kJ·mol^(-1), respectively. Additionally, water vapor is more likely to diffuse into the coke interior at a lower temperature and thus aggravates the deterioration of coke in the middle upper part of blast furnace.

关键词： coke gasification dissolution reaction deep reaction rate-limiting step activation energy

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Influence of compression-expansion effect on oscillating-flow heat transfer in a finned heat exchanger

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第6期14卷 427-434页

作者： ke TANG Juan YU Tao JIN zhi-hua GAN Institute of Refrigeration and Cryogenics Zhejiang University

Compression and expansion of a working gas due to the pressure oscillation of an oscillating flow can lead to a temperature variation of the working gas, which will affect the heat transfer in the oscillating flow. This study focuses on the impact of the compression-expansion effect, indicated by the pressure ratio, on the heat transfer in a finned heat exchanger under practical operating conditions of the ambient-temperature heat exchangers in Stirling-type pulse tube refrigerators. The experimental results summarized as the Nusselt number are presented for analysis. An increase in the pressure ratio can result in a marked rise in the Nusselt number, which indicates that the compression-expansion effect should be considered in characterizing the heat transfer of the oscillating flow, especially in the cases with a higher Valensi number and a lower maximum Reynolds number.

关键词： Heat transfer Heat exchanger Oscillating flow Pressure ratio Pulse robe refrigerator

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A numerical piston-type wave-maker toolbox for the open-source library OpenFOAM

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Journal of Hydrodynamics 2019年第4期31卷 800-813页

作者： Dong-xu wang Jia-wen Sun Jin-song Gui Zhe Ma De-zhi Ning ke-zhao Fang Department of Ocean and Civil Engineering Dalian Ocean University Dalian 116023 China National Marine Environment Monitoring Center State Oceanic Administration Dalian 116023 China Deepwater Engineering Research Center Dalian University of Technology Dalian 116024 China State key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

A novel numerical piston-type wave-maker toolbox for the OpenFOAM is developed and demonstrated in this paper. This toolbox is implemented in C++ for improving the solutions of nonlinear wave problems in the field of hydrodynamics. As a toolbox that generates waves using the piston-type method only, it contains several frequently used functions, including the generation and the absorption of waves of various forms, an active absorption system and the porous media flow. Furthermore, to illustrate the operability of the toolbox, some validations and applications are presented, including the regular waves, the irregular waves, and the solitary waves. In each case, a satisfactory agreement is obtained in comparison with the published experimental or theoretical results,so this toolbox may be applied with a considerable confidence.

关键词： Piston-type wave-maker OpenFOAM nonlinear wave hydrodynamics

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A reusable planar triggered spark-gap switch batched-fabricated with PCB technology for medium- and low-voltage pulse power systems

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Defence Technology（防务技术） 2021年第4期17卷 1572-1578页

作者： zhi Yang ke wang Peng Zhu Peng Liu Qiu Zhang Cong Xu Hao-tian Jian Rui-qi Shen School of Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China key Laboratory of Special Energy Materials Ministry of EducationNanjing210094China Micro-Nano Energetic Devices key Laboratory Ministry of Industry and Information TechnologyNanjing210094China

Triggered spark-gap switch is a popular discharge switch for pulse power *** studies have focused on planarizing this switch using thin film techniques in order to meet the requirements of compact size in the *** switches are one-shot due to electrodes being too thin to sufficiently resist ***,these switches did not employ any structures in securing internal gas composition,resulting in inconsistent performance under harsh *** this work,a novel planar triggered spark-gap switch(PTS)with a hermetically sealed cavity was batched-prepared with printed circuit board(PCB)technology,to achieve reusability with low *** proposed PTS was inspected by micro-computed tomography to ensure PCB techniques meet the requirements of machining *** results from electrical experiments demonstrated that PCB PTS were consistent and reusable with lifespan over 20 *** calculated switch voltage and circuit current were consistent with those derived from real-world ***,PCB PTS was used to introduce hexanitrostilbene(HNS)pellets in a pulse power system to verify its performance.

关键词： Pulse power systems Printed circuit board technology Triggered spark-gap switch Planar discharge switch Electrical performance

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Analysis of the tetraquark and hexaquark molecular states with the QCD sum rules

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Communications in Theoretical Physics 2021年第6期73卷 80-93页

作者： zhi-Gang wang Department of Physics North China Electric Power UniversityBaoding 071003China

In this article,we construct the color-singlet-color-singlet type currents and the color-singlet-colorsinglet-color-singlet type currents to study the scalar D*■*,D*D*tetraquark molecular states and the vector D*D*■*,D*D*D*hexaquark molecular states with the QCD sum rules in *** calculations,we choose the pertinent energy scales of the QCD spectral densities with the energy scale formula■for the tetraquark and hexaquark molecular states respectively in a consistent *** obtain stable QCD sum rules for the scalar D*■*,D*D*tetraquark molecular states and the vector D*D*■*hexaquark molecular state,but cannot obtain stable QCD sum rules for the vector D*D*D*hexaquark molecular *** connected(nonfactorizable)Feynman diagrams at the tree level(or the lowest order)and their induced diagrams via substituting the quark lines make positive contributions for the scalar D*D*tetraquark molecular state,but make negative or destructive contributions for the vector D*D*D*hexaquark molecular *** is of no use or meaningless to distinguish the factorizable and nonfactorizable properties of the Feynman diagrams in the color space in the operator product expansion so as to interpret them in terms of the hadronic observables,we can only obtain information about the short-distance and long-distance contributions.

关键词： tetraquark molecular states hexaquark molecular states QCD sum rules

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Photosynthetic Characterization of the Plant Dicranopteris dichotoma Bernh. in a Rare Earth Elements Mine

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Journal of Integrative Plant Biology 2005年第9期47卷 1092-1100页

作者： Li-Feng wang Hong-Bing JI ke-zhi BAI Liang-Bi LI Ting-Yun KUANG key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany the Chinese Academy of Sciences Beijing 100093 China The Subcenter of the Environmental Processes National Engineering Center for Urban Environmental Pollution Control the Capital Normal University Beijing 100037 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

In order to investigate the distribution of rare earth elements （REEs） in the natural hyperaccumulator fern Dicranopteris dichotoma Bernh. and to characterize this plant photosynthetically, concentrations of REEs in D. dichotoma from mines mining heavy and light REEs （HREEs and LREEs, respectively）, as well as in D. dichotoma from an area in which no mining occurred, in southern Jiangxi Province were determined using inductively coupled plasma-mass spectrometry. The REE concentrations in the lamina of D. dichotoma were in the order LREEs mine 〉 HREEs mine 〉 non-mining area. The maximum REE content in the lamina of D. dichotoma from the LREE mine was approximately 2 648 mg/kg dry weight. The photosynthetic activity of D. dichotoma from areas of HREE and LREE mines was improved by the presence of high concentrations of REEs in the lamina compared with D. dichotoma from the non-mining area. However, this enhancement varied according to the concentrations of the REEs, as well as their type. In addition, 77K fluorescence, electron transport rate, and chlorophyll-protein complex studies showed that the enhancement of the photosynthetic activity of D. dichotoma from HREE mines was mainly due to an increase in the chlorophyll-protein complex of the reaction center of photosystem （PS） Ⅰ, whereas the enhancement observed in D. dichotoma from LREE mines was due to an increase in the internal antennae chlorophyll-protein complex of PS Ⅱ and greater light energy distribution to the light-harvesting chlorophyll-protein complex of PS Ⅱ.

关键词： chlorophyll-protein complex Dicranopteris dichotoma electron transport rate rare earth elements (REEs).

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Chronic stress causes protein kinase C epsilon-aldehyde dehydrogenase 2 signaling pathway perturbation in the rat hippocampus and prefrontal cortex,but not in the myocardium

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Neural Regeneration Research 2018年第7期13卷 1225-1230页

作者： Wen-Yuan Zhang ke-Yi wang Yun-Jing Li Ying-Ran Li Rong-zhi Lu Department of Pharmacy Zhongshan Hospital of Sun Yat-sen University Department of Magnetic Resonance Imaging Zhongshan Hospital of Sun Yat-sen University

Chronic stress is strongly associated with the occurrence and development of depression and cardiovascular *** can induce altered mitochondrial function and activation of apoptosis in the cardio-cerebral ***,it is unknown whether the protein kinase C ε（PKCε）-aldehyde dehydrogenase 2（ALDH2） pathway is altered under chronic stress,and this study sought to address this question.A rat model of depression was established using a chronic unpredictable mild stress（CUMS） *** experiencing CUMS for 4 weeks,the sucrose preference test and the forced swim test verified depressive-like *** linked immunosorbent assays showed that ALDH2 activity was decreased in the rat hippocampus and prefrontal cortex,but was not altered in the *** blot assays demonstrated reduced levels of ALDH2 and PKCε,but increased levels of 4-hydroxy-2-nonenal（4 HNE） ***-3 expression did not obviously alter,but active forms of caspase-3 were increased in the hippocampus and prefrontal *** the myocardium,expression of ALDH2,PKCε and 4 HNE adducts did not remarkably alter;while caspase-3 expression was reduced and the active forms of caspase-3 were ***＇s correlation test demonstrated that expression of 4 HNE adducts was positively correlated with levels of the active forms of caspase-3 in the hippocampus and prefrontal cortex,but not in the *** conclusion,chronic stress can damage the PKCε-ALDH2 signaling pathway in the hippocampus and prefrontal cortex,but not in the ***,4 HNE is associated with active forms of caspase-3 in the hippocampus and prefrontal cortex.

关键词： nerve regeneration stress depression protein kinase C ε aldehyde dehydrogenase 2 4-hydroxy-2-nonenal apoptosis hippocampus prefrontal cortex myocardium neural regeneration

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Feasibility and safety of single-incision laparoscopic cholecystectomy versus conventional laparoscopic cholecystectomy in an ambulatory setting

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Hepatobiliary & Pancreatic Diseases International 2019年第3期18卷 273-277页

作者： Jun-Wen Qu Cheng Xin Gui-Yang wang zhi-Qing Yuan ke-Wei Li Department of Biliary-Pancreatic Surgery Renji Hospital School of Medicine Shanghai Jiao Tong University

Background: Single-incision laparoscopic surgery has emerged as an alternative to conventional laparoscopic cholecystectomy(LC) in the clinical setting. Limited information is available on the possibility of performing single-incision laparoscopic surgery as an ambulatory procedure. This study aimed to determine the feasibility and safety of single-incision laparoscopic cholecystectomy(SILC) versus conventional LC in an ambulatory setting. Methods: Ninety-one patients were randomized to SILC( n = 49) or LC( n = 42). The success rate, operative duration, blood loss, hospital stay, gallbladder perforation, drainage, delayed discharge, readmission, total cost, complications, pain score, vomiting, and cosmetic satisfaction of the two groups were then compared. Results: There were significant differences in the operative time(46.89 ± 10.03 min in SILC vs. 37.24 ± 10.23 min in LC;P 0.05). Conclusions: Ambulatory SILC is safe and feasible for selected patients. The advantages of SILC as compared with LC are improved cosmetic satisfaction and lower total costs.

关键词： Ambulatory Single incision Laparoscopic cholecystectomy Feasibility Safety

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Compressive Strength of Tubular Members with Combined Pitting Corrosion and Crack Damage

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China Ocean Engineering 2023年第4期37卷 613-627页

作者： wang Ren-hua wang zhi-wen Department of Civil Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available *** effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion *** methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined *** was shown that the former is practical but complex while the next always over-estimates the residual ***,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and *** effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged *** on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.

关键词： tubular member pitting damage crack damage combined damage ultimate strength

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