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Impacts of Ice-Ocean Stress on the Subpolar Southern Ocean:Role of the Ocean Surface Current
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作者 Yang WU Zhaomin WANG +1 位作者 Chengyan LIU Liangjun YAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第2期293-309,共17页
The mechanical influences involved in the interaction between the Antarctic sea ice and ocean surface current(OSC)on the subpolar Southern Ocean have been systematically investigated for the first time by conducting t... The mechanical influences involved in the interaction between the Antarctic sea ice and ocean surface current(OSC)on the subpolar Southern Ocean have been systematically investigated for the first time by conducting two simulations that include and exclude the OSC in the calculation of the ice-ocean stress(IOS), using an eddy-permitting coupled ocean-sea ice global model. By comparing the results of these two experiments, significant increases of 5%, 27%, and 24%, were found in the subpolar Southern Ocean when excluding the OSC in the IOS calculation for the ocean surface stress,upwelling, and downwelling, respectively. Excluding the OSC in the IOS calculation also visibly strengthens the total mechanical energy input to the OSC by about 16%, and increases the eddy kinetic energy and mean kinetic energy by about38% and 12%, respectively. Moreover, the response of the meridional overturning circulation in the Southern Ocean yields respective increases of about 16% and 15% for the upper and lower branches;and the subpolar gyres are also found to considerably intensify, by about 12%, 11%, and 11% in the Weddell Gyre, the Ross Gyre, and the Australian-Antarctic Gyre, respectively. The strengthened ocean circulations and Ekman pumping result in a warmer sea surface temperature(SST), and hence an incremental surface heat loss. The increased sea ice drift and warm SST lead to an expansion of the sea ice area and a reduction of sea ice volume. These results emphasize the importance of OSCs in the air-sea-ice interactions on the global ocean circulations and the mass balance of Antarctic ice shelves, and this component may become more significant as the rapid change of Antarctic sea ice. 展开更多
关键词 subpolar Southern Ocean Antarctic sea ice ice-ocean stress air-sea-ice-ocean interaction ocean surface current MITgcm-ECCO2
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Light-modulated graphene-based φ_(0) Josephson junction and -φ_(0) to φ_(0) transition
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作者 程任翔 于苗 +4 位作者 汪洪 曹德亮 李兴鳌 戚凤华 周兴飞 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期476-481,共6页
We investigate the chiral edge states-induced Josephson current–phase relation in a graphene-based Josephson junction modulated by the off-resonant circularly polarized light and the staggered sublattice potential.By... We investigate the chiral edge states-induced Josephson current–phase relation in a graphene-based Josephson junction modulated by the off-resonant circularly polarized light and the staggered sublattice potential.By solving the Bogoliubov–de Gennes equation,a φ_(0) Josephson junction is induced in the coaction of the off-resonant circularly polarized light and the staggered sublattice potential,which arises from the fact that the center of-mass wave vector of Cooper pair becomes finite and the opposite center of-mass wave vector to compensate is lacking in the nonsuperconducting region.Interestingly,when the direction of polarization of light is changed,-φ_(0) to φ_(0) transition generates,which generalizes the concept of traditional 0–πtransition.Our findings provide a purely optical way to manipulate a phase-controllable Josephson device and guidelines for future experiments to confirm the presence of graphene-based φ_(0)Josephson junction. 展开更多
关键词 GRAPHENE circularly polarized light staggered sublattice potential φ_(0)Josephson junction
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Landscape Design of the Ming Dynasty Outer City Wall in Nanjing from the Perspective of Experience Tourism
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作者 YU Ziping 《Journal of Landscape Research》 2018年第6期134-136,共3页
Taking a section of the Ming Dynasty Outer City Wall from Xianhe Gate to Qilin Gate for example, this paper proposed the landscape design from the perspective of experience tourism, highlighted the wal, and took the b... Taking a section of the Ming Dynasty Outer City Wall from Xianhe Gate to Qilin Gate for example, this paper proposed the landscape design from the perspective of experience tourism, highlighted the wal, and took the beautiful environment and rich history and cultures of the Ming Dynasty Outer City Wall as the essential experience elements, to build cultural recreational corridors with the theme of "experiencing the Ming Dynasty culture", so that visitors will get unforgettable experience, tourism quality, popularity of the Ming Dynasty Outer City Wall as well as its cultural and educational significance will be further promoted. 展开更多
关键词 Experience TOURISM The Ming DYNASTY Outer City Wall CULTURAL CORRIDOR LANDSCAPE
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Identification of 1q21.1 microduplication in a family:A case report
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作者 Ting-Ting Huang Hai-Feng Xu +7 位作者 Shang-Yu Wang Wen-Xin Lin Yie-Hen Tung Kaleem Ullah Khan Hui-HuiZhang Hu Guo Guo Zheng Gang Zhang 《World Journal of Clinical Cases》 SCIE 2023年第4期874-882,共9页
BACKGROUND Copy number variation(CNV)has become widely recognized in recent years due to the extensive use of gene screening in developmental disorders and epilepsy research.1q21.1 microduplication syndrome is a rare ... BACKGROUND Copy number variation(CNV)has become widely recognized in recent years due to the extensive use of gene screening in developmental disorders and epilepsy research.1q21.1 microduplication syndrome is a rare CNV disease that can manifest as multiple congenital developmental disorders,autism spectrum disorders,congenital malformations,and congenital heart defects with genetic heterogeneity.CASE SUMMARY We reported a pediatric patient with 1q21.1 microduplication syndrome,and carried out a literature review to determine the correlation between 1q21.1microduplication and its phenotypes.We summarized the patient’s medical history and clinical symptoms,and extracted genomic DNA from the patient,her parents,elder brother,and sister.The patient was an 8-mo-old girl who was hospitalized for recurrent convulsions over a 2-mo period.Whole exon sequencing and whole genome low-depth sequencing(CNV-seq)were then performed.Whole exon sequencing detected a 1.58-Mb duplication in the CHR1:145883867-147465312 region,which was located in the 1q21.1 region.Family analysis showed that the pathogenetic duplication fragment,which was also detected in her elder brother’s DNA originated from the mother.CONCLUSION Whole exon sequencing combined with quantitative polymerase chain reaction can provide an accurate molecular diagnosis in children with 1q21.1 microduplication syndrome,which is of great significance for genetic counseling and early intervention. 展开更多
关键词 1q21.1 microduplication syndrome EPILEPSY Copy number variation FAMILIAL Whole exon sequencing Congenital developmental disorders Case report
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Forecasting Future Trajectories with an Improved Transformer Network
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作者 Wei Wu Weigong Zhang +2 位作者 Dong Wang Lydia Zhu Xiang Song 《Computers, Materials & Continua》 SCIE EI 2023年第2期3811-3828,共18页
An increase in car ownership brings convenience to people’s life.However,it also leads to frequent traffic accidents.Precisely forecasting surrounding agents’future trajectories could effectively decrease vehicle-ve... An increase in car ownership brings convenience to people’s life.However,it also leads to frequent traffic accidents.Precisely forecasting surrounding agents’future trajectories could effectively decrease vehicle-vehicle and vehicle-pedestrian collisions.Long-short-term memory(LSTM)network is often used for vehicle trajectory prediction,but it has some shortages such as gradient explosion and low efficiency.A trajectory prediction method based on an improved Transformer network is proposed to forecast agents’future trajectories in a complex traffic environment.It realizes the transformation from sequential step processing of LSTM to parallel processing of Transformer based on attentionmechanism.To performtrajectory predictionmore efficiently,a probabilistic sparse self-attention mechanism is introduced to reduce attention complexity by reducing the number of queried values in the attention mechanism.Activate or not(ACON)activation function is adopted to select whether to activate or not,hence improving model flexibility.The proposed method is evaluated on the publicly available benchmarks nextgeneration simulation(NGSIM)and ETH/UCY.The experimental results indicate that the proposed method can accurately and efficiently predict agents’trajectories. 展开更多
关键词 Trajectory prediction TRANSFORMER attention mechanism ACON activation intelligent perception
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ML and CFD Simulation of Flow Structure around Tandem Bridge Piers in Pressurized Flow
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作者 Aliasghar Azma Ramin Kiyanfar +4 位作者 Yakun Liu Masoumeh Azma Di Zhang Ze Cao Zhuoyue Li 《Computers, Materials & Continua》 SCIE EI 2023年第4期1711-1733,共23页
Various regions are becoming increasingly vulnerable to the increased frequency of floods due to the recent changes in climate and precipitation patterns throughout the world.As a result,specific infrastructures,notab... Various regions are becoming increasingly vulnerable to the increased frequency of floods due to the recent changes in climate and precipitation patterns throughout the world.As a result,specific infrastructures,notably bridges,would experience significant flooding for which they were not intended and would be submerged.The flow field and shear stress distribution around tandem bridge piers under pressurized flow conditions for various bridge deck widths are examined using a series of three-dimensional(3D)simulations.It is indicated that scenarios with a deck width to pier diameter(Ld/p)ratio of 3 experience the highest levels of turbulent disturbance.In addition,maximum velocity and shear stresses occur in cases with Ld/p equal to 6.Results indicate that increasing the number of piers from 1 to 2 and 3 results in the increase of bed shear stress by 24%and 20%respectively.Finally,five machine learning algorithms,including Decision Trees(DT),Feed Forward Neural Networks(FFNN),and three Ensemble models,are implemented to estimate the flow field and the turbulent structure.Results indicated that the highest accuracy for estimation of U,and W,were obtained using AdaBoost ensemble with R2=0.946 and 0.951,respectively.Besides,the Random Forest algorithm outperformed AdaBoost slightly in the estimation of V and turbulent kinetic energy(TKE)with R2=0.894 and 0.951,respectively. 展开更多
关键词 Bridge pier scour process deck width machine learning turbulent structure
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Research on Career Identity in China:A Literature Review
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作者 Huaruo Chen Ya Wen +3 位作者 Fei Liu Yihong Zhao Zhiyao Xie Xuehui Zhang 《International Journal of Mental Health Promotion》 2023年第2期153-172,共20页
Career identity is one of the important topics to study the psychological problems of employees,especially after the outbreak of CoV-19.Being a populous country in the world,China has a large number of employees from ... Career identity is one of the important topics to study the psychological problems of employees,especially after the outbreak of CoV-19.Being a populous country in the world,China has a large number of employees from all walks of life,and its research on career identity has attracted more and more attention.Thus,this study aims to sort out the history,characteristics,and trends of the research on career identity in China through a literature review,which can help more scholars pay attention to China’s career identity research.In this study,Citespace is used to statistically analyze the selected literature from China’s National Knowledge Infrastructure(CNKI)and Web of Science(WOS).The results show that:(1)The historical evolution of career identity research in China can be divided into three stages:germination,development and maturity.(2)From the perspective of cooperation between authors and institutions,researchers tend to do independent research,mainly focusing on the research in the field of psychology.(3)From the key words,career identity and employability are the main high-frequency words.(4)From the cluster analysis,the research focuses mainly include social support,teachers’career identity,influencing factors,and job involvement.(5)From the emergent analysis,it can be seen that the research on roles and differences between urban and rural areas is weakening,and the research on factors such as job satisfaction is gradually strengthening as the frontier theme.Finally,according to the existing analysis results,this study predicts the future trend of career identity in China and thinks that it will extend from the fields of concept explanation,interdisciplinary research,scientific research tools,and so on. 展开更多
关键词 Career identity scientific knowledge maps historical evolution research hot spot career education
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A Critical Discourse Analysis of Cyberbullying Language Based on Text-mining Techniques——A Case Study of Prince Harry and Meghan Markle
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作者 ZHANG Shen-hui WANG Qiong 《Journal of Literature and Art Studies》 2023年第8期593-599,共7页
With the development of AI,a large amount of cyberbullying language flooded into the Internet.Cyberbullying language damages the online environment and causes mental harm to the victims of online bullying.Many researc... With the development of AI,a large amount of cyberbullying language flooded into the Internet.Cyberbullying language damages the online environment and causes mental harm to the victims of online bullying.Many researchers,therefore,have paid much attention to the problem.This study collected online comments targeted at Prince Harry and Meghan Markle as a corpus and then analyzed text data based on Critical Discourse Analysis by using text-mining tools to explore the factors that contribute to the social ideological effects of the cyberbullying language.The research results show that cultural differences,prejudice,or social exclusion due to race or gender form cyberbullying on social media. 展开更多
关键词 cyberbullying language critical discourse analysis text-mining technology non-traditional texts
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New Public Sphere and Public Discourse in the Context of Globalisation
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作者 SHEN Lei 《Journal of Literature and Art Studies》 2023年第8期607-616,共10页
This paper explores the concept of the new public sphere and public discourse in the context of globalisation.It starts by analyzing how globalisation has affected the emergence of the new public sphere and the role t... This paper explores the concept of the new public sphere and public discourse in the context of globalisation.It starts by analyzing how globalisation has affected the emergence of the new public sphere and the role that digital technologies have played in it.The influence of the new public sphere on public discourse during globalisation is discussed,along with how it has affected accessibility,citizen engagement,and power dynamics.The paper also examines the various issues that the new public sphere during globalisation brings to the forefront of public discourse,such as the increased spread of false information,polarization of opinion,marginalization of oppressed groups,cultural appropriation,privacy concerns,surveillance,censorship,and the digital divide.It concludes by arguing that the new public sphere and public discourse during globalisation can be beneficial but should be managed carefully to ensure it is a positive force for society. 展开更多
关键词 public sphere public discourse globalisation digital technologies
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A Modified Model of Ecological Footprint Accounting and Its Application to Cropland in Jiangsu,China 被引量:21
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作者 LIU Qin-Pu LIN Zhen-Shan +1 位作者 FENG Nian-Hua LIU Yong-Mei 《Pedosphere》 SCIE CAS CSCD 2008年第2期154-162,共9页
Based on the theory of emergy analysis,a modified model of ecological footprint accounting,termed emergetic ecological footprint(EMEF)in contrast to the conventional ecological footprint(EF)model,is formulated and app... Based on the theory of emergy analysis,a modified model of ecological footprint accounting,termed emergetic ecological footprint(EMEF)in contrast to the conventional ecological footprint(EF)model,is formulated and applied to a case study of Jiangsu cropland,China.Comparisons between the EF and the EMEF with respect to grain,cotton,and food oil were outlined.Per capita EF and EMEF of cropland were also presented to depict the resources consumption level by comparing the biocapacity(BC)or emergetic biocapacity(EMBC,a new BC calculation by emergy analysis) of the same area.In the meanwhile,the ecological sustainability index(ESI),a new concept initiated by the authors, was established in the modified model to indicate and compare the sustainability of cropland use at different levels and between different regions.The results from conventional EF showed that per capita EF of the cropland has exceeded its per capita BC in Jiangsu since 1986.In contrast,based on the EMBC,the per capita EMEF exceeded the per capita EMBC 5 years earlier.The ESIs of Jiangsu cropland use were between 0.7 and 0.4 by the conventional method,while the numbers were between 0.7 and 0.3 by the modified one.The fact that the results of the two methods were similar showed that the modified model was reasonable and feasible,although some principles of the EF and EMEF were quite different. Also,according to the realities of Jiangsu cropland use,the results from the modified model were more acceptable. 展开更多
关键词 农田 生态学足迹模型 江苏 土壤
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Synergistic effect between Sn and K promoters on supported platinum catalyst for isobutane dehydrogenation 被引量:12
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作者 Yiwei Zhang Yuming Zhou +3 位作者 Lihui Wan Mengwei Xue Yongzheng Duan Xuan Liu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第6期639-646,共8页
Catalytic dehydrogenation of isobutane has recently received considerable attention because of the increasing demand for isobutene.In this study,the synergistic effect between Sn and K on PtSnK/γ-Al2O3 catalysts has ... Catalytic dehydrogenation of isobutane has recently received considerable attention because of the increasing demand for isobutene.In this study,the synergistic effect between Sn and K on PtSnK/γ-Al2O3 catalysts has been investigated by changing the content of Sn.It was found that with the presence of potassium,suitable addition of Sn could not only increase the metal dispersion,but also reduce the catalyst acidity.In these cases,the synergistic effect could also strengthen the interactions between the metal and support,which resulted in an increase in both catalytic activity and stability.In our experiments,Pt-0.6SnK/Al catalyst exhibited the lowest deactivation rate (12.4%) and showed a selectivity to isobutene higher than 94% at the isobutane conversion of about 45.3% after running the reaction for 6 h.However,with the excessive loading of Sn,surface property of active sites and the interactions between metal and support were changed.As a result,the initial optimal ratio between the metallic function and acid function would be destroyed,which was disadvantageous to the reaction. 展开更多
关键词 铂催化剂 协同效应 催化脱氢 锡含量 异丁烷 金属功能 表面活性中心 相互作用
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Control system design of flying-wing UAV based on nonlinear methodology 被引量:10
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作者 Ji-guang LI Xin CHEN +1 位作者 Ya-juan LI Rong ZHANG 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2017年第6期397-405,共9页
In this paper, A fluid vector rudder flying-wing UAV is employed as the design object, so as to study the nonlinear design method and flight validation. For the maneuvering flight control, this paper presents a contro... In this paper, A fluid vector rudder flying-wing UAV is employed as the design object, so as to study the nonlinear design method and flight validation. For the maneuvering flight control, this paper presents a control structure. This control structure included the inner loop linearization decoupling methods to eliminate the known negative coupling and the outer loop backstepping methods for trajectory tracking control. The stability of the control structure has been proved in this paper. Compared with the traditional backstepping control method, this controller increases the inner loop decoupling structure and retains the aerodynamic damping term which makes the linearized system a weak nonlinear system.This structure can not only reduce the conservatism of the outer loop controller design, but also is convenient for engineering implementation. Simulation and flight validation results show that the proposed control scheme is effective. 展开更多
关键词 UAV PAPER FLIGHT VALIDATION
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Period-control and chaos-anti-control of a semiconductor laser using the twisted fiber 被引量:4
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作者 颜森林 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第9期257-263,共7页
A novel semiconductor laser system is presented based on a twisted fiber.To study the period-control and chaos-anticontrol of the laser system,we design a type of optic path as a control setup using the combination of... A novel semiconductor laser system is presented based on a twisted fiber.To study the period-control and chaos-anticontrol of the laser system,we design a type of optic path as a control setup using the combination of the twisted fiber and the polarization controller while we present a physical dynamics model of the delayed dual-feedback laser containing the twisted fiber effect.We give an analysis of the effect of the twisted fiber on the laser.We use the effects of the delayed phase and the rotation angle of the twisted fiber and the characteristics of the system to achieve control of the laser.The laser is deduced to a stable state,a double-periodic state,a period-6 state,a period-8 state,a period-9 state,a multi-period state,beat phenomenon,and so on.The periodic laser can be anti-controlled to chaos.Some chaos-anti-control area is found.The laser system is very useful for the study of chaos-control of the laser setup and the applications of some physics effects. 展开更多
关键词 半导体激光器 混沌反控制 周期控制 光纤 稳定状态 激光系统 偏振控制器 模型控制
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Effect of cerium addition on catalytic performance of PtSnNa/ZSM-5 catalyst for propane dehydrogenation 被引量:6
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作者 Mengwei Xue Yuming Zhou +3 位作者 Yiwei Zhang Xuan Liu Yongzheng Duan Xiaoli Sheng 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第3期324-331,共8页
The effect of cerium addition on the catalytic performance of propane dehydrogenation over PtSnNa/ZSM-5 catalyst has been investigated by reaction tests and some physicochemical characterization such as XRD,BET,TEM,XP... The effect of cerium addition on the catalytic performance of propane dehydrogenation over PtSnNa/ZSM-5 catalyst has been investigated by reaction tests and some physicochemical characterization such as XRD,BET,TEM,XPS,NH 3-TPD,H 2 chemisorption,TPR and TPO techniques.It has been found that with suitable amount of cerium addition,the platinum dispersion increased,while the carbon deposition tended to be eliminated easily.In these cases,the presence of cerium could not only realize the better distribution of metallic particles on the support,but also strengthen the interactions between Sn species and the support.Additionally,XPS spectra confirmed that more amounts of tin could exist in oxidized form,which was advantageous to the reaction.In our experiments,PtSnNaCe(1.1 wt%)/ZSM-5 catalyst exhibited the best catalytic performance.After running the reaction for 750 h,propane conversion was maintained higher than 30% with the corresponding selectivity to propylene of about 97%. 展开更多
关键词 催化性能 丙烷脱氢 脱氢催化剂 ZSM-5催化剂 X射线光电子能谱 NH3-TPD X射线衍射
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The Suitability of Using Leaf Area Index to Quantify Soil Loss under Vegetation Cover 被引量:7
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作者 ZHANG Wentai YU Dongsheng +4 位作者 SHI Xuezheng WANG Hongjie GU Zhujun ZHANG Xiangyan TAN Manzhi 《Journal of Mountain Science》 SCIE CSCD 2011年第4期564-570,共7页
Soil erosion by water under forest cover is a serious problem in southern China.A comparative study was carried out on the use of leaf area index(LAI) and vegetation fractional coverage(VFC) in quantifying soil loss u... Soil erosion by water under forest cover is a serious problem in southern China.A comparative study was carried out on the use of leaf area index(LAI) and vegetation fractional coverage(VFC) in quantifying soil loss under vegetation cover.Five types of vegetation with varied LAI and VFC under field conditions were exposed to two rainfall rates(40 mm h-1 and 54 mm h-1) using a portable rainfall simulator.Runoff rate,sediment concentration and soil loss rate were measured at relatively runoff stable state.Significant negative exponential relationship(p < 0.05,R2 = 0.83) and linear relationship(p < 0.05,R2 = 0.84) were obtained between LAI and sediment concentration,while no significant relationship existed between VFC and sediment concentration.The mechanism by which vegetation canopy prevents soil loss was by reducing rainfall kinetic energy and sediment concentration.LAI could better quantify such a role than VFC.However,neither LAI nor VFC could explain runoff rate or soil loss rate.Caution must be taken when using LAI to quantify the role of certain vegetation in soil and water conservation. 展开更多
关键词 植被覆盖 叶面积指数 量化 土壤流失量 损失 水土保持作用 VFC 含沙量
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Synthesis and Crystal Structure of a Cobalt(Ⅱ) Coordination Polymer with Benzene-1,3,5-triacetate and 1,4-Di(1H-imidazol-1-yl)benzene 被引量:4
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作者 刘光祥 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第7期933-938,共6页
A novel coordination polymer, [Co3 (bta)2(dib)2]·4H2O (1, H3bta=benzene-1,3,5-triacetic acid, and dib=1,4-di(1H-imidazol-1-yl)benzene), has been hydrothermally prepared and characterized by IR spectroscopy, eleme... A novel coordination polymer, [Co3 (bta)2(dib)2]·4H2O (1, H3bta=benzene-1,3,5-triacetic acid, and dib=1,4-di(1H-imidazol-1-yl)benzene), has been hydrothermally prepared and characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The crystal is of triclinic system, space group Pī, with a=9.141(2), b=9.667(2), c=13.855(2), α=100.83(3), β=90.81(3), γ=100.94(3)°, V=1179.0(4)3 , C48H46N8O16Co3 , Mr=1167.72, Dc=1.645 g/cm 3 , F(000)=599, μ=1.127 mm-1 and Z=1. The final R=0.0634 and wR=0.1703 for 4291 observed reflections (I > 2σ(I)). In the title complex, the bta ligand acts as a four-dentate bridging ligand to link up cobalt atoms into a lamellar framework, which are further interlinked by the dib ligands to generate a binodal (3,8)-connected tfz-d net. 展开更多
关键词 配位聚合物 水热法合成 晶体结构 钴原子 咪唑 单晶X-射线衍射 桥联配体
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Analyzing Forest Effects on Runoff and Sediment Production Using Leaf Area Index 被引量:4
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作者 WU Xiao-Xia GU Zhu-Jun +2 位作者 LUO Hao SHI Xue-Zheng YU Dong-Sheng 《Journal of Mountain Science》 SCIE CSCD 2014年第1期119-130,共12页
Quantifying the effects of forests on water and soil conservation helps further understanding of ecological functions and improving vegetation reconstruction in water-eroded areas.Studies on the effects of vegetation ... Quantifying the effects of forests on water and soil conservation helps further understanding of ecological functions and improving vegetation reconstruction in water-eroded areas.Studies on the effects of vegetation on water and soil conservation have generally focused on vegetation types or vegetation horizontal distribution densities.However,only a few studies have used indicators that consider the vegetation vertical distribution.This study used the leaf area index(LAI) to investigate the relationship between forests and water and soil conservation in experimental plots.From 2007 to 2010,rainfall characteristics,LAI,and water and soil loss in 144 natural erosive rainfall events were measured from five pure tree plots(Pinus massoniana).These tree plots were located in Hetian Town,Changting County,Fujian Province,which is a typical water-eroded area in Southern China.Quadratic polynomial regression models for LAI and water/soil conservation effects(RE/SE) were established for each plot.The RE and SE corresponded to the ratios of the runoff depth(RD) and the soil loss(SL) of each pure tree plot to those of the control plot under each rainfall event.The transformation LAIs of the LAI–RE and LAI–SE curves,as well as the rainfall characteristics for the different water/soil conservation effects,were computed.The increasing LAI resulted in descending,descending–ascending,ascending–descending,and ascending trends in the LAI–RE and LAI–SE curves.The rainfall frequencies corresponding to each trend of LAI–RE and LAI–SE were different,and the rainfall distributions were not uniform per year.The effects of soil conservation in the plots were superior to those of water conservation.Most of the RE and SE values presented a positive effect on water and soil conservation.The main factor that caused different effects was rainfall intensity.During heavy rains(e.g.,rainfall erosivity R = 145 MJ mm/ha h and maximum 30 min intensity I30 = 13 mm/h),the main effects were positive,whereas light rains(e.g.,R = 70 MJ mm/ha h and I30 = 8 mm/h) generally led to negative effects.When the rainfall erosivity was lower than that of the positive or the negative effects to a threshold and the tree LAI reached a transformation value,the relationships between LAI and RE or SE notably transformed.Results showed that the plottransformation LAIs for water and soil conservation during rainfall events were both approximately 1.0 in our study.These results could be used to come up with a more efficient way to alleviate water and soil loss in water-eroded areas. 展开更多
关键词 Water loss SOIL EROSION PINUS massoniana SOIL CONSERVATION Transformation LAI
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Effect of Mischmetal Addition on Catalytic Performance of PtSnNa/ZSM-5 for Propane Dehydrogenation 被引量:4
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作者 Xue Mengwei Zhou Yuming +3 位作者 Huang Li Zhang Yiwei Duan Yongzheng Sheng Xiaoli 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2011年第3期47-52,共6页
The influence of mischmetal addition on physicochemical properties of PtSnNa/ZSM-5 catalyst was studied by means of XRF,H 2 chemisorption,XRD,TPR,NH 3-TPD and TPO techniques.The results showed that the presence of mis... The influence of mischmetal addition on physicochemical properties of PtSnNa/ZSM-5 catalyst was studied by means of XRF,H 2 chemisorption,XRD,TPR,NH 3-TPD and TPO techniques.The results showed that the presence of mischmetal had an obvious impact on the catalytic performance of the PtSnNa/ZSM-5 catalyst.A suitable content of mischmetal not only could enhance the interactions between Pt species and the support,but also inhibit the formation of coke during the reaction,thus improving the catalytic activity and stability.In our experiments,when the content of mischmetal was 3m%,the catalyst exhibited best catalytic performance.However,the continuous addition of mischmetal could promote the reduction of Sn species to metallic tin,which was disadvantageous to the reaction. 展开更多
关键词 混合稀土 催化性能 丙烷脱氢 ZSM-5催化剂 X射线荧光光谱 反应过程 化学吸附 相互作用
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A Model for Estimating Total Forest Coverage with Ground-Based Digital Photography 被引量:5
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作者 GU Zhu-Jun ZENG Zhi-Yuan +5 位作者 SHI Xue-Zheng LI Lin D. C. WEINDORF ZHA Yong YU Dong-Sheng LIU YongoMei 《Pedosphere》 SCIE CAS CSCD 2010年第3期318-325,共8页
Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shr... Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P < 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy. 展开更多
关键词 覆盖模型 森林面积 数字摄影 地面 估计 甘油三酯 植被覆盖度 均方根误差
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A Novel Approach for QoS Prediction Based on Bayesian Combinational Model 被引量:3
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作者 Pengcheng Zhang Yingtao Sun +2 位作者 Hareton Leung Meijun Xu Wenrui Li 《China Communications》 SCIE CSCD 2016年第11期269-280,共12页
As an important factor in evaluating service,QoS(Quality of Service) has drawn more and more concerns with the rapid increasing of Web services. However,due to the great volatility of services in Mobile Internet envir... As an important factor in evaluating service,QoS(Quality of Service) has drawn more and more concerns with the rapid increasing of Web services. However,due to the great volatility of services in Mobile Internet environments,such as internet of vehicles,Web services often do not work as announced and thus cause unacceptable problems. QoS prediction can avoid failure before it takes place,which is considered a more effective way to assure quality. However,Current QoS prediction approaches neither consider the highly dynamic of Web services,nor maintain good prediction performance all the time. Consequently we propose a novel Bayesian combinational model to predict QoS by continuously adjusting credit values of the basic models so as to keep good prediction accuracy. QoS attributes such as response time,throughput and reliability are used to validate the proposed model. Experimental results show that the model can provide stable prediction results in Mobile Internet environments. 展开更多
关键词 预测性能 组合模型 QOS 贝叶斯 WEB服务 移动互联网 服务质量 故障发生
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