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Estimation of Turbulent Fluxes Using the Flux-Variance Method over an Alpine Meadow Surface in the Eastern Tibetan Plateau 被引量:11
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作者 WANG Shaoying ZHANG Yu +2 位作者 LU Shihua LIU Heping SHANG Lunyu 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第2期411-424,共14页
The flux-variance similarity relation and the vertical transfer of scalars exhibit dissimilarity over different types of surfaces, resulting in different parameterization approaches of relative transport efficiency am... The flux-variance similarity relation and the vertical transfer of scalars exhibit dissimilarity over different types of surfaces, resulting in different parameterization approaches of relative transport efficiency among scalars to estimate turbulent fluxes using the flux-variance method. We investigated these issues using eddycovariance measurements over an open, homogeneous and flat grassland in the eastern Tibetan Plateau in summer under intermediate hydrological conditions during rainy season. In unstable conditions, the temperature, water vapor, and CO2 followed the flux-variance similarity relation, but did not show in precisely the same way due to different roles (active or passive) of these scalars. Similarity constants of temperature, water vapor and CO2 were found to be 1.12, 1.19 and 1.17, respectively. Heat transportation was more eft% cient than water vapor and CO2. Based on the estimated sensible heat flux, five parameterization methods of relative transport efficiency of heat to water vapor and CO2 were examined to estimate latent heat and CO2 fluxes. The strategy of local determination of flux-variance similarity relation is recommended for the estimation of latent heat and CO2 fluxes. This approach is better for representing the averaged relative transport efficiency, and technically easier to apply, compared to other more complex ones. 展开更多
关键词 flux-variance method relative transfer efficiency eddy-covariance method homogeneous landsurface turbulent flux
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A Sound Quality Objective Evaluation Method Based on Auditory Peripheral Simulation Model 被引量:1
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作者 Yinhan Gao~1,Jun Xie~2,Jie Liang~1,Xin Chang~3,Baojun Wu~2 1.Experimental Centre of Testing Science,Jilin University,Changchun 130022,P.R.China 2.College of Instrumentation & Electrical Engineering,Jilin University,Changchun 130061,P.R.China 3.Laboratory of Applications and Computations in Electromagnetics and Optics,Department of Electrical Engineering, University of Washington,WA 98195-2500,USA 《Journal of Bionic Engineering》 SCIE EI CSCD 2010年第2期199-208,共10页
Based on auditory peripheral simulation model, a new Sound Quality Objective Evaluation (SQOE) method is presented,which can be used to model and analyze the impacts of head, shoulder and other parts of human body on ... Based on auditory peripheral simulation model, a new Sound Quality Objective Evaluation (SQOE) method is presented,which can be used to model and analyze the impacts of head, shoulder and other parts of human body on sound wave trans-mission.This method employs the artificial head technique, in which the head related transfer function was taken into account tothe outer ear simulation phase.First, a bionic artificial head was designed as the outer ear model with considering the outersound field in view of theory and physical explanations.Then the auditory peripheral simulation model was built, which mimicsthe physiological functions of the human hearing, simulating the acoustic signal transfer process and conversion mechanismsfrom the free field to the peripheral auditory system.Finally, performance comparison was made between the proposed SQOEmethod and ArtemiS software, and the verifications of subjective and objective related analysis were made.Results show thatthe proposed method was economical, simple, and with good evaluation quality. 展开更多
关键词 sound quality objective evaluation auditory peripheral simulation model artificial head head related transfer function
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Exploring a Deep Analysis Method for “Click-Stream” Information from the Perspective of the Flow of Bidirectional Value of Customer Relations Based on Ricoeur's Hermeneutic Theory
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作者 王素芬 仓平 +1 位作者 封均康 潘晨隐 《Journal of Donghua University(English Edition)》 EI CAS 2010年第3期321-329,共9页
Click-streams of online shopping are the tracks/trails of interactions between a customer and a vendor.We observe that it is of great importance both in theory and practice to explore a deep analysis method for analyz... Click-streams of online shopping are the tracks/trails of interactions between a customer and a vendor.We observe that it is of great importance both in theory and practice to explore a deep analysis method for analyzing click-stream information of an individual customer in a specific transaction for understanding the bidirectional value transfer within the machine-human interaction of an online store and for its personalization.We analyze the significance,the hierarchical structure and the characteristics of click-stream information and propose that Ricoeur's hermeneutic theory be the foundation of forming such a deep analysis method.Then we use the empirical context information of the click-stream to improve the naive interpretation put forward by Ricoeur.Moreover,we apply the Grounded Theory to extend the deep analysis of Ricoeur's theory of textual interpretation.The improved theory fits well with the needs of interpretation and the analysis of click-stream information.We exemplify and show the feasibility of this analysis method by using data collected(a single case)from a large study of human-computer interaction. 展开更多
关键词 click-stream human-computer interaction bidirectional value transfer of customer relations Ricoeur’s hermeneutic theory
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Transfer relation between subgrade frost heave and slab track deformation and vehicle dynamic response in seasonally frozen ground
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作者 Juanjuan REN Junhong DU +2 位作者 Kaiyao ZHANG Bin YAN Jincheng TIAN 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2024年第2期130-146,共17页
Subgrade frost heave in seasonally frozen ground can greatly influence the safety and smooth running of high-speed trains and the service performance of track structures.In this study,we used a static model to:(1)inve... Subgrade frost heave in seasonally frozen ground can greatly influence the safety and smooth running of high-speed trains and the service performance of track structures.In this study,we used a static model to:(1)investigate track-subgrade frost heave and develop a dynamic model of vehicle-track-subgrade frost heave;(2)explore the transfer relation between subgrade frost heave and track structure deformation;(3)examine the characteristics of interlayer debonding;(4)study the influence of subgrade frost heave on the dynamic response of vehicles in high-speed railways in seasonally frozen regions.A Fourier series was used to fit the frost heave waveform and simulate the behavior of subgrade uneven frost heave using data collected on-site.The results show:(i)The position of frost heave significantly affects the transfer of deformation to a slab track.The largest deformation of the track slab,with the amplitude transfer ratio reaching 20%,was recorded when the frost heave occurred near the joint of the base plate.(ii)At the same frost heave amplitude,long-wave frost heave causes smaller deformation and debonding of the track structure than short-wave frost heave.In the wavelength range of 10-30 m,the main frequency of the acceleration spectral density was concentrated between 3.5 and 3.7 Hz,with larger frost heave wavelengths producing smaller superposition on the vertical acceleration of the vehicle.(ii)The maximum wheel-rail force occurs when the front bogie passes the frost heave peak,with greater frost heave amplitudes producing greater wheel-rail force.From these results,we conclude there is a clear need to control the frost heave deformation of the track to reduce the dynamic response of the vehicle and in turn improve train operatSubgrade frost heave in seasonally frozen ground can greatly influence the safety and smooth running of high-speed trains and the service performance of track structures.In this study,we used a static model to:(1)investigate track`-subgrade frost heave and develop a dynamic model of vehicle`-track`-subgrade frost heave;(2)explore the transfer relation between subgrade frost heave and track structure deformation;(3)examine the characteristics of interlayer debonding;(4)study the influence of subgrade frost heave on the dynamic response of vehicles in high-speed railways in seasonally frozen regions.A Fourier series was used to fit the frost heave waveform and simulate the behavior of subgrade uneven frost heave using data collected on-site.The results show:(i)The position of frost heave significantly affects the transfer of deformation to a slab track.The largest deformation of the track slab,with the amplitude transfer ratio reaching 20%,was recorded when the frost heave occurred near the joint of the base plate.(ii)At the same frost heave amplitude,long-wave frost heave causes smaller deformation and debonding of the track structure than short-wave frost heave.In the wavelength range of 10-30 m,the main frequency of the acceleration spectral density was concentrated between 3.5 and 3.7 Hz,with larger frost heave wavelengths producing smaller superposition on the vertical acceleration of the vehicle.(iii)The maximum wheel`-rail force occurs when the front bogie passes the frost heave peak,with greater frost heave amplitudes producing greater wheel`-rail force.From these results,we conclude there is a clear need to control the frost heave deformation of the track to reduce the dynamic response of the vehicle and in turn improve train operations.ions. 展开更多
关键词 Slab track Subgrade frost heave transfer relation Vehicle-track-subgrade coupling Dynamic response
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Relation between sound transfer function from diffuse sound field to the eardrum and temporary threshold shift
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作者 Yvonne I. Hanna Ramzy W. Melik (National Institute for Standards (NIS), Aconstic Department Tersa Str., El-Hararn, Giza, Egypt) 《Chinese Journal of Acoustics》 1999年第3期259-265,共7页
Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated... Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated to the temporary threshold shift (TTS) due to fiffuse-exposure.A probe tube with a miniature microphone was used for STF measurements in which successive 1/3 oct bandwidth random noise with central frequency from 0.25 kKz to 8 kHz were used. The subjects were divided into two groups, with the STF maxima at 2 kHz and 4 kHz respectively Pre- and post- exposure sweep Bekesy audiograms were recorded and the temporary thresh old shift calctilated as the difference between the two. Frequency of the maximum TTS was correlated to that of the maximum STF. The average TTS was very small or zero at frequen cies below the band noise exposure , but was noticeable even at the highest measured frequency (8 kHz) for beyond the noise band. Also individual differences in STF were found at frequencies between 2 kHz and 4 kHz 展开更多
关键词 KHZ AM In Relation between sound transfer function from diffuse sound field to the eardrum and temporary threshold shift
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A comparison on the phytoremediation ability of triazophos by different macrophytes 被引量:2
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作者 Zhu Li Huiping Xiao +3 位作者 Shuiping Cheng Liping Zhang Xiaolong Xie Zhenbin Wu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第2期315-322,共8页
The strategy of choosing suitable plants should receive great performance in phytoremediation of surface water polluted by triazophos (O,O-diethyl-O-(1-phenyl- 1,2,4-triazol-3-base) sulfur phosphate, TAP), which i... The strategy of choosing suitable plants should receive great performance in phytoremediation of surface water polluted by triazophos (O,O-diethyl-O-(1-phenyl- 1,2,4-triazol-3-base) sulfur phosphate, TAP), which is an organophosphorus pesticide widespread applied for agriculture in China and moderately toxic to higher animal and fish. The tolerance, uptake, transformation and removal of TAP by twelve species of macrophytes were examined in a hydroponic system and a comprehensive score (CS) of five parameters (relative growth rate (RGR), biomass, root/shoot ratio, removal capacity (RC), and bio-concentration factor (BCF)) by factor analysis was employed to screen the potential macrophyte species for TAP phytoremediation. The results showed that Thalia dealbata, Cyperus alternifolius, Canna indica and Acorus calamus had higher RGR values, indicating these four species having stronger growth capacity under TAP stress. The higher RC loading in Iris pseudacorus and Cyperus rotundus were 42.11 and 24.63μg/(g fw.day), respectively. The highest values of BCF occurred in A. calamus (1.17), and TF occurred in Eichhornia crassipes (2.14). Biomass and root/shoot ratio of plant showed significant positive correlation with first-order kinetic constant of TAP removal in the hydroponic system, indicating that plant biomass and root system play important roles in remediation of TAP. Five plant species including C. alternifolius, A. calamus, T. dealbata, C. indica and Typha orientalis, which owned higher CS, would be potential species for TAP phytoremediation of contaminated water bodies. 展开更多
关键词 pesticide removal capacity relative growth rate bio-concentration factor transfer factor root/shoot ratio factor analysis
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