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Characteristic parameters of pollutant emissions from building materials:high-precision measurement,model modification and environmental coupling effects 认领 引用
1
作者 Yuan Ma Yan Zhang +2 位作者 Jiemin Liu Zhongbao Guo Hongyan Guan 《ENGINEERING Environment》 SCIE EI CAS CSCD 2026年第3期45-63,共19页
Characteristic parameters play a pivotal role in the precise quantification of volatile organic compounds(VOCs)/formaldehyde emissions.The concentration history(C-history)method is currently widely used for determinin... Characteristic parameters play a pivotal role in the precise quantification of volatile organic compounds(VOCs)/formaldehyde emissions.The concentration history(C-history)method is currently widely used for determining characteristic parameters.However,for airtight chamber experiments,this method requires measuring the equilibrium concentration of pollutants.For ventilated chamber experiments,the calculation results of this method cannot reflect the concentration of pollutants released in the early stages accurately.Therefore,this paper presents an improved airtight chamber Chistory method.It eliminates the need to determine the pollutant equilibrium concentration.Compared with the existing method,it can accurately determine parameters using only the first half of the experimental data.Furthermore,in a ventilated chamber,the first two terms of the infinite-series analytical solution for the mass transfer model are used as an approximation.On this basis,a doubleexponential ventilated chamber C-history method is developed to determine characteristic parameters.Compared with the previous approach,this method shortens the experimental time required for parameter calculation by nearly 40 h.The correlation coefficients(R2)between the simulation results and the experimental data is greater than 0.90,confirming the effectiveness of the method.In addition,on the basis of the MIP testing results for porous building materials and dimensional balance principles,empirical formulas for the diffusion and partition coefficients are modified.The modified formulas yield R2 values greater than 0.93,validating the credibility of the proposed relationships.Ultimately,an exponential empirical model was formulated to determine the coupling effects of temperature and relative humidity on formaldehyde emissions. 展开更多
关键词 Characteristic parameters C-method Indoor air quality(IAQ) Empirical formula Pollutant
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Research progress in digital auscultation:equipment and systems,characteristic parameters,and their application in diagnosis of pulmonary diseases and syndromes 认领 引用
2
作者 Shuyi ZHANG Tao JIANG Jiatuo XU 《Digital Chinese Medicine》 CAS CSCD 2025年第1期20-27,共8页
Traditional Chinese medicine(TCM)auscultation has a long history,and with advancements in equipment and analytical methods,the quantitative analysis of auscultation parameters has determined.However,the complexity and... Traditional Chinese medicine(TCM)auscultation has a long history,and with advancements in equipment and analytical methods,the quantitative analysis of auscultation parameters has determined.However,the complexity and diversity of auscultation,along with variations in devices,analytical methods,and applications,bring challenges to its standardization and deeper application.This review presents the advancements in auscultation equipment and systems,auscultation characteristic parameters,and their application in the diagnosis of pulmonary diseases and syndromes over the past 10 years,while also exploring the progress and challenges of current digital research of auscultation.This review also proposes the establishment of standardized protocols for the collection and analysis of auscultation data,the incorporation of advanced artificial intelligence(AI)auscultation analysis methods,and an exploration of the diagnostic utility of auscultatory features in pulmonary diseases and syndromes,so as to provide more precise decision support for intelligent diagnosis of pulmonary diseases and syndromes. 展开更多
关键词 Digital auscultation Equipment and systems Characteristic parameters Pulmonary diseases and syndromes Intelligent diagnosis
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Characteristic parameters of electromagnetic signals from a human heart system 认领 引用 被引量：3
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作者 刘新元 裴留庆 +3 位作者 王寅 张素明 高红蕾 戴远东 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第4期456-464,共9页
The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography （ECG） and magnetocardiography （MCG） are both carriers of electromagnetic information about the cardiac system, a... The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography （ECG） and magnetocardiography （MCG） are both carriers of electromagnetic information about the cardiac system, and they are nonstationary signals. In this study, ECG and MCG data from healthy subjects are acquired; the MCG data are captured using a high-Tc radio frequency superconducting quantum interference device （HTc rf SQUIDs） and the QRS complexes in these data are analysed by the evolutionary spectrum analysis method. The results show that the quality factor Q and the central frequency fz of the QRS complex evolutionary spectrum are the characteristic parameters （CHPs） of ECG and MCG in the time-frequency domain. The confidence intervals of the mean values of the CHPs are estimated by the Student t distribution method in mathematical statistics. We believe that there are threshold ranges of the mean values of Q and fz for healthy subjects. We have postulated the following criterion： if the mean values of CHPs are in the proper ranges, the cardiac system is in a normal condition and it possesses the capability of homeostasis. In contrast, if the mean values of the CHPs do not lie in the proper ranges, the homeostasis of the cardiac system is lacking and some cardiac disease may follow. The results and procedure of MCG CHPs in the study afford a technological route for the application of HTc rf SQUIDs in cardiology. 展开更多
关键词 bioelectromagnetic field magnetocardiography electrocardiography characteristic parameters threshold ranges
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Prestack seismic stochastic inversion based on statistical characteristic parameters 认领 引用 被引量：4
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作者 Wang Bao-Li Lin Ying +2 位作者 Zhang Guang-Zhi Yin Xing-Yao Zhao Chen 《Applied Geophysics》 SCIE CSCD 2021年第1期63-74,129,共12页
In the conventional stochastic inversion method,the spatial structure information of underground strata is usually characterized by variograms.However,effectively characterizing the heterogeneity of complex strata is ... In the conventional stochastic inversion method,the spatial structure information of underground strata is usually characterized by variograms.However,effectively characterizing the heterogeneity of complex strata is difficult.In this paper,multiple parameters are used to fully explore the underground formation information in the known seismic reflection and well log data.The spatial structure characteristics of complex underground reservoirs are described more comprehensively using multiple statistical characteristic parameters.We propose a prestack seismic stochastic inversion method based on prior information on statistical characteristic parameters.According to the random medium theory,this method obtains several statistical characteristic parameters from known seismic and logging data,constructs a prior information model that meets the spatial structure characteristics of the underground strata,and integrates multiparameter constraints into the likelihood function to construct the objective function.The very fast quantum annealing algorithm is used to optimize and update the objective function to obtain the fi nal inversion result.The model test shows that compared with the traditional prior information model construction method,the prior information model based on multiple parameters in this paper contains more detailed stratigraphic information,which can better describe complex underground reservoirs.A real data analysis shows that the stochastic inversion method proposed in this paper can effectively predict the geophysical characteristics of complex underground reservoirs and has a high resolution. 展开更多
关键词 prior information random medium theory statistical characteristic parameters stochastic inversion very fast quantum annealing
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Synthetically quantitative evaluation function of characteristic parameters on CO_2 arc welding process 认领 引用 被引量：5
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作者 俞建荣 蒋力培 +2 位作者 史耀武 孙振国 王军波 《China Welding》 EI CAS 2001年第1期19-26,共8页
The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis show... The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis shows that the sensitivity of each characteristic parameter with regard to the variation of the short circuiting transfer process is different. The sensitivity of 4 kinds among these characteristic parameters is more intense than that of the short circuiting transfer frequency. In order to take account of the synthetic influence of these characteristic parameters, by means of the characteristic parameters synthetic value, a quantitative evaluation function is built up to describe and evaluate the short circuiting transfer process of CO 2 arc welding in real time. The testing shows that the evaluation function can give a suitable synthetic valuation for the short circuiting transfer process with a variety of welding variables. 展开更多
关键词 CO 2 arc welding process characteristic parameters quantitative evaluation function
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An Inverse Method for Equivalent Gray Gas Radiation Characteristic Parameter 认领 引用 被引量：1
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作者 ZHANG Wei-jun YI Zhi +2 位作者 LIU Xiao-ting LI Guo-jun CHEN Hai-geng 《Journal of Iron and Steel Research International》 SCIE CAS CSCD 2013年第4期1-5,共5页
Compared with non-gray model,equivalent gray model has equal calculation accuracy but much higher computing speed.To solve the existing problems of the equivalent gray method,sole ternary model was developed.In the mo... Compared with non-gray model,equivalent gray model has equal calculation accuracy but much higher computing speed.To solve the existing problems of the equivalent gray method,sole ternary model was developed.In the model,coupling solving process of energy balance equations is omitted and the model zone is real closed.Meanwhile,the full furnace temperature and heat flow calculations are avoided,which makes it easier to find the relationship between the equivalent gray gas radiation characteristic parameter and the initial conditions.The radiation characteristic parameter was calculated with different temperature combinations,different model zone sizes and different partial pressures of absorbent gas.The results show the similar variations in the absorption coefficient and emissivity for the equivalent gray model,which both decrease with the increase of the gas temperature and the surface temperature（especially the former one）as well as the model zone size while increase with the increase of the partial pressure of absorbent gas. 展开更多
关键词 equivalent gray radiation characteristic parameter sole ternary model
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The influence of MoS_2 on tribology characteristic parameter of Ni60A/MoS_2 composite lubricating coating 认领 引用 被引量：1
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作者 ZHAO Yun-cai GE Shi-rong 《Journal of Coal Science & Engineering(China)》 2010年第1期94-98,共5页
The influence of MoS2 on the tribology characteristic parameter of Ni60A/MoS2 composite lubricating coating was researched on the UMT-2 fretting abrasion tester （USA） The result shows that with increasing content of... The influence of MoS2 on the tribology characteristic parameter of Ni60A/MoS2 composite lubricating coating was researched on the UMT-2 fretting abrasion tester （USA） The result shows that with increasing content of MoS2, the hardness curve of the composite coating decreases and the trend accelerates. Under the same experimental conditions, the mass loss of plasma spray composite coating without adding MoS2 iS 1.27×10^-2 mg. When the amount of MoS2 reaches 35%, the mass loss is 0.96×10^-2 mg. It can be seen that adding MoS2 phase can improve the wear resistance, the amplitude of which is close to 30%. The friction coefficient of plasma spray composite coating without adding MoS2 is 0.23. Adding MoSz could decrease the friction coefficient of the coating and presents a downtrend. When the mass fraction is 35%, the friction coefficient is the smallest （0.13）, and the range is doubled. 展开更多
关键词 plasma spraying MoS2 phase composite lubricant coating tribology characteristic parameter friction coefficient
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Research on the adjustment model of ventilation characteristic parameters based on integrated method of circuit and path 认领 引用
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作者 Ting-gui JIA Shu-gang WANG +1 位作者 Guo-na QU Jian LIU 《Journal of Coal Science & Engineering(China)》 2013年第1期33-37,共5页
Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult t... Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult to obtain accurate results. In order to check the ventilation characteristic parameters of mines more accurately, the integrated method of circuit and path is adopted to overcome the drawbacks caused by the traditional path method or circuit method in the digital debugging process of ventilation system, which can improve the large local error or the inconsistency between the airflow direction and the actual situation caused by inaccuracy of the ventilation characteristic parameters or checking in the ventilation network solution. The results show that this method can effectively reduce the local error and prevent the pseudo-airflow reversal phenomenon; in addition, the solution results are consistent with the actual situation of mines, and the effect is obvious. 展开更多
关键词 path method circuit method ventilation network adjustment model ventilation characteristic parameter
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Estimations of Land Surface Characteristic Parameters and Turbulent Heat Fluxes over the Tibetan Plateau Based on FY-4A/AGRI Data 认领 引用 被引量：3
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作者 Nan GE Lei ZHONG +5 位作者 Yaoming MA Yunfei FU Mijun ZOU Meilin CHENG Xian WANG Ziyu HUANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第8期1299-1314,共16页
Accurate estimates of land surface characteristic parameters and turbulent heat fluxes play an important role in the understanding of land-atmosphere interaction.In this study,Fengyun-4A(FY-4A)Advanced Geostationary R... Accurate estimates of land surface characteristic parameters and turbulent heat fluxes play an important role in the understanding of land-atmosphere interaction.In this study,Fengyun-4A(FY-4A)Advanced Geostationary Radiation Imager(AGRI)satellite data and the China Land Data Assimilation System(CLDAS)meteorological forcing dataset CLDAS-V2.0 were applied for the retrieval of broadband albedo,land surface temperature(LST),radiation flux components,and turbulent heat fluxes over the Tibetan Plateau(TP).The FY-4A/AGRI and CLDAS-V2.0 data from 12 March 2018 to 30 April 2018 were first used to estimate the hourly turbulent heat fluxes over the TP.The time series data of in-situ measurements from the Tibetan Observation and Research Platform were divided into two halves-one for developing retrieval algorithms for broadband albedo and LST based on FY-4A,and the other for the cross validation.Results show the root-mean-square errors(RMSEs)of the FY-4A retrieved broadband albedo and LST were 0.0309 and 3.85 K,respectively,which verifies the applicability of the retrieval method.The RMSEs of the downwelling/upwelling shortwave radiation flux and downwelling/upwelling longwave radiation flux were 138.87/32.78 W m−2and 51.55/17.92 W m−2,respectively,and the RMSEs of net radiation flux,sensible heat flux,and latent heat flux were 58.88 W m−2,82.56 W m−2and 72.46 W m−2,respectively.The spatial distributions and diurnal variations of LST and turbulent heat fluxes were further analyzed in detail. 展开更多
关键词 FY-4A/AGRI land surface characteristic parameters turbulent heat fluxes Surface Energy Balance System model Tibetan Plateau
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Research on Characteristic Parameters of Lightning Discharge Channels Based on Spectrum 认领 引用 被引量：1
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作者 Caixia DONG 《Meteorological and Environmental Research》 2021年第2期20-22,共3页
According to the time-resolved spectra of lightning return stroke process and based on the plasma transmission theory,the evolution characteristics of the thermal conductivity and thermal diffusion coefficient of the ... According to the time-resolved spectra of lightning return stroke process and based on the plasma transmission theory,the evolution characteristics of the thermal conductivity and thermal diffusion coefficient of the discharge channel over time during the lightning return stroke are discussed.The radial distribution of the channel temperature in the lightning peak current phase is calculated,and the heat transfer along the radial direction of the channel is analyzed.The calculated transmission characteristic parameter values of the lightning discharge channel are all in a reasonable range.The results show that the heat transport coefficient of the lightning channel is closely related to the channel temperature and electron density.After returning to the peak current,the channel temperature slowly decreases,and the transport coefficient shows a non-linear and monotonous decay trend.The closer to the current core channel is,the greater the temperature gradient is,and the more the heat transferred radially outward is. 展开更多
关键词 Lightning discharge channel Thermal conductivity Transport coefficient Characteristic parameter
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Testing Research about Characteristic Parameters of the Grounding Device at 750 kV Substation of Riyue Mountain,Qinghai 认领 引用
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作者 Chengshan Yang Yanjun Xin 《Meteorological and Environmental Research》 2013年第8期14-16,20,共3页
750 kV substation of Riyue Mountain, Qinghai is a substation that annual average thunderstorm days are the maximum at the same volt- age level and altitude in the wodd. We detailedly described testing methods and step... 750 kV substation of Riyue Mountain, Qinghai is a substation that annual average thunderstorm days are the maximum at the same volt- age level and altitude in the wodd. We detailedly described testing methods and steps of 6 characteristic parameters for grounding device of 750 kV substation by using 8000S comprehensive test system, and scientifically judged overall performance of the grounding device. Moreover, we espe- cially emphasized key and difficult points in testing process, providing reference for the majority of grounding test workers. 展开更多
关键词 750 kV substation Grounding device Characteristic parameters Testing research China
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Some Characteristic Parameters of the Basic Components of the Solar Radio Emission 认领 引用 被引量：1
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作者 Ji Shuchen $$ 《天文研究与技术》 1999年第S1期457-460,共4页
Four basic components of the solar radio emission: the quiet sun, the slowly varying component (SVC), the radio burst and the ultra-fast varying component (UFVC) are studied. As their six characteristic parameters: ra... Four basic components of the solar radio emission: the quiet sun, the slowly varying component (SVC), the radio burst and the ultra-fast varying component (UFVC) are studied. As their six characteristic parameters: radiation source, brightness temperature, radiation lifetime, polarized radiation, radiation mechanism, and character of superposition are affirmed. 展开更多
关键词 Radio Some Characteristic Parameters of the Basic Components Basic of the Solar Radio Emission
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Orbital parameter characterization and objects cataloging for Earth-Moon collinear libration points 认领 引用
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作者 Chenyuan QIAO Xi LONG +2 位作者 Leping YANG Yanwei ZHU Peng WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2026年第4期551-566,共16页
Owing to the chaotic and non-integrable nature of three-body dynamics,the conventional Keplerian elements are rendered inadequate for cataloging cislunar space objects.Currently,there has been a conspicuous absence of... Owing to the chaotic and non-integrable nature of three-body dynamics,the conventional Keplerian elements are rendered inadequate for cataloging cislunar space objects.Currently,there has been a conspicuous absence of universally recognized parameters for the characterization and cataloging of such objects,thereby posing an urgent challenge to cislunar space situational awareness.This paper proposes a novel approach to parameterize the orbits of Earth-Moon collinear libration points by leveraging the theoretical frameworks of canonical transformations.First,under the Hamiltonian-form dynamical equations of the libration point,symplectic transformations are employed to extract 3 modes of motion from locally linearized part.A subsequent canonical transformation then decouples the hyperbolic invariant manifold from the center manifold within the nonlinear remainder.Finally,6 characteristic parameters obtained via action-angle variables are established in a bijective correspondence with the state variables,where two parameters characterize the motion of the invariant manifold and four parameters characterize the motion of the central manifold.Furthermore,a distribution map of the Earth-Moon libration point orbits is drawn utilizing Poincare sections,which can be used to describe the distribution of libration point object.Simulation results demonstrate that the proposed parameters are not only applicable to orbit identification and object cataloging but also exhibit remarkable consistency and robustness against variations in observation arc length and observational errors. 展开更多
关键词 Canonical transformation Characteristic parameters Cislunar space Collinear libration points Objects cataloging Orbital calculations Spacecraft
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Determination of key soil characteristic parameters using angle of repose and direct shear stress test 认领 引用 被引量：8
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作者 Qizhi Yang Lei Shi +4 位作者 Aiping Shi Mingsheng He Xiaoqi Zhao Li Zhang Min Addy 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第3期143-150,共8页
Discrete element modelling(DEM)is a numerical method for examining the dynamic behavior of granular media.In order to build an accurate simulation model and provide more comprehensive soil characteristic parameters fo... Discrete element modelling(DEM)is a numerical method for examining the dynamic behavior of granular media.In order to build an accurate simulation model and provide more comprehensive soil characteristic parameters for the design and optimization of various soil contact machinery,in this paper,the discrete element simulation method(EDEM)combined with experimental approach is used to investigate the soil contact characteristic parameters in East Asia.In this study,Hertze-Mindlin(no slip)was used as a particle contact model by taking particle contact parameters and soil JKR(Johnson-Kendall-Roberts)surface energy as determinants,and repose angle,internal friction angle,and cohesive force as evaluation indexes.The method of Plackett-Burman,Stepest ascent,and Box-Behnken were used to gradually reduce the range of parameters needed for simulation until the most accurate value was determined.The results show that the restitution coefficient,static friction coefficient,and rolling friction coefficient between soil particles have significant effects on the DEM model,and their value of them are 0.596,0.725,and 0.16,respectively.Based on these parameters used for the repose angle test and direct shear stress test,the value of repose angle is 31.97°,the internal friction angle is 27.61°,and the cohesive force is 33.06 kPa.The relative errors with the actual measured values are 9.54%,1.87%,and 2.31%,respectively.In order to further test whether the simulation parameters of soil obtained by repose angle test and direct shear stress test are consistent with the real soil,comparison test between field test and discrete element simulation was used.The results show that the error in height of ridge between the simulated soil and the actual soil is 4.06%,which is within the acceptable range.It also indicates that the calibrated and optimized soil simulation model can accurately represent the real soil.The research provides theoretical basis and technical support for the study of soil contact parts by using the discrete element method,combined with repose angle test and direct shear stress test. 展开更多
关键词 soil characteristic parameters calibration repose angle direct shear stress discrete element
Load Distribution Assessment of Reinforced Concrete Buildings During Construction with Structural Characteristic Parameter Approach 认领 引用 被引量：3
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作者 方东平 席海峰 +2 位作者 王晓明 张传敏 赵挺生 《Tsinghua Science and Technology》 EI CAS 2009年第6期746-755,共10页
High-rise reinforced concrete buildings are in great demand in developing countries with rapid urbanization. Construction engineers are facing more and more safety control challenges. One major issue is the understand... High-rise reinforced concrete buildings are in great demand in developing countries with rapid urbanization. Construction engineers are facing more and more safety control challenges. One major issue is the understanding of the load distributions, especially the maximum slab load, of structures under construction, which is time dependent. Previous methods were mainly targeted to specific examples, providing specific solutions without addressing the fundamental issues of finding general solutions for load distributions in reinforced concrete buildings with different geometrical and material characteristics during construction. The concept of a structural characteristic parameter is used here to parametedze the main geometrical and material characteristics of concrete structures for generalized assessments of load distributions during construction. The maximum slab load for 20 different construction shoringeshoring schemes is presented. The results indicate that the traditional simplified method may underestimate or overestimate the maximum slab load, depending mainly on the shoringeshoring schemes. The structural characteristic parameter approach was specifically developed to assist construction engineers to estimate load distributions to assure safe construction procedures. 展开更多
关键词 reinforced concrete buildings construction load re-distdbution structural characteristic parameter： slab-shore interaction
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Reconstruction of characteristic parameters of underwaterelastic composite tubular targets 认领 引用 被引量：1
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作者 WANG Renqian and LI Yingchun Received 《Chinese Journal of Acoustics》 1997年第2期152-161,共10页
By using a ray method, a physical model that the backscattering of a tube is simplilied into reflection of a plane wave on layered media is suggested and reconstruction formulas of the parameters of a metallic tube co... By using a ray method, a physical model that the backscattering of a tube is simplilied into reflection of a plane wave on layered media is suggested and reconstruction formulas of the parameters of a metallic tube covered with sound-absorbing materials under the conditions of high frequency, fard field and thin tube are given. The internal and external radii of an aluminium tube filled by water or air and thickness of the covered material are reconstructed by using computer simulation and experimellts. The theoretical tesults obtained by this method are supported by experiments. 展开更多
关键词 Am Reconstruction of characteristic parameters of underwaterelastic composite tubular targets
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Development of the Ocean Dumping Dredged Material Disposal Model Based on Experimental Measurements 认领 引用
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作者 LUO Xiao-feng DING Wei +2 位作者 BAI Yi-bing ZHANG Gong-jin LU Chuan-teng 《China Ocean Engineering》 SCIE EI CSCD 2026年第3期634-643,共10页
Dredging is a critical approach for estuary improvement and development and remains one of the most practical solutions to sedimentation problems.Dredged sediments are typically transported by suction hopper dredgers ... Dredging is a critical approach for estuary improvement and development and remains one of the most practical solutions to sedimentation problems.Dredged sediments are typically transported by suction hopper dredgers and disposed of at designated offshore dumping sites.Accurate prediction of the formation and evolution of subaqueous sediment mounds is therefore essential for minimizing the ecological and environmental impacts associated with secondary sediment transport.This study conducts a series of experimental tests examining the morphology and classification of sediment subaqueous mounds formed through continuous release of coarse sediment under static and dynamic flow conditions.Observations indicate that mounds can be classified as regular cones or oblique elliptic cones under hydrodynamic forces.Based on diffusion theory,this research develops a theoretical model describing the subaqueous mound formation process.Four key characteristic parameters are identified to characterize mound shape:peak height,radiation length,peak offset distance,and turbulence-induced diffusion length.These parameters are expressed as functions of dimensionless numbers:sand Reynolds number,flow Reynolds number,density Froude number,and characteristic length.The findings demonstrate that the process model incorporating peak offset distance and diffusion length more accurately predicts drift characteristics and skew distribution of sediment subaqueous mounds. 展开更多
关键词 sediment subaqueous mound process model characteristic parameters dredging
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Extraction of gravel characteristics and spatial inversion for ecological restoration monitoring in the Northern Tibetan Plateau 认领 引用
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作者 KONG Bo YU Huan +3 位作者 QIU Xia HU Wenkai HE Bing GUAN Xudong 《Journal of Mountain Science》 SCIE CSCD 2025年第2期556-574,共19页
Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial rol... Previous studies have often focused on monitoring grassland growth as the primary target of remote sensing investigations on grassland ecological restoration in the northern Tibetan Plateau,overlooking the crucial role played by gravel in the ecological restoration of these grasslands.This study utilizes supervised classification and segmentation techniques based on machine learning to extract gravel morphology profiles from field-sampled plot images and calculate their characteristic parameters.Employing a multivariate linear approach combined with Principal Component Analysis(PCA),a model for inferring gravel characteristic parameters is constructed.Statistical features,particle size characteristics,and spatial distribution patterns of gravel are analyzed.Results reveal that gravel predominantly exhibit sub-rounded shapes,with 80%classified as fine gravel.The coefficients of determination(R2)between gravel particle size and coverage,perimeter,and area are 0.444,0.724,and 0.557,respectively,indicating linear relationships.The cumulative contribution rate of the top five remote sensing factors is 95.44%,with the first geological factor contributing 77.64%,collectively reflecting the primary information of the 20 factors used.Modeling shows that areas with larger gravel particle sizes correspond to increased perimeter and coverage.Gravels in the Nagqu Prefecture of northern Xizang have a particle size range of 4-8 mm,primarily comprising fine gravel which accounts for 94.61%.These findings provide a scientific basis for extracting gravel characteristic parameters and understanding their spatial distribution variations in the northern Tibetan Plateau. 展开更多
关键词 Gravel characteristics parameters Northern Tibetan Plateau Gravel outline extraction Remote sensing inversion Grassland degradation
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DBN-GABP model for estimation of aircraft wake vortex parameters using Lidar data 认领 引用 被引量：5
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作者 Zhiqiang WEI Tong LU +1 位作者 Runping GU Fei LIU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第9期347-368,共22页
Aircraft wake turbulence is an inherent outcome of aircraft flight,presenting a substan-tial challenge to air traffic control,aviation safety and operational efficiency.Building upon data obtained from coherent Dopple... Aircraft wake turbulence is an inherent outcome of aircraft flight,presenting a substan-tial challenge to air traffic control,aviation safety and operational efficiency.Building upon data obtained from coherent Doppler Lidar detection,and combining Dynamic Bayesian Networks(DBN)with Genetic Algorithm-optimized Backpropagation Neural Networks(GA-BPNN),this paper proposes a model for the inversion of wake vortex parameters.During the wake vortex flow field simulation analysis,the wind and turbulent environment were initially superimposed onto the simulated wake velocity field.Subsequently,Lidar-detected echoes of the velocity field are simulated to obtain a data set similar to the actual situation for model training.In the case study validation,real measured data underwent preprocessing and were then input into the established model.This allowed us to construct the wake vortex characteristic parameter inversion model.The final results demonstrated that our model achieved parameter inversion with only minor errors.In a practical example,our model in this paper significantly reduced the mean square error of the inverted velocity field when compared to the traditional algorithm.This study holds significant promise for real-time monitoring of wake vortices at airports,and is proved a crucial step in developing wake vortex interval standards. 展开更多
关键词 Air traffic control Wake vortex flow field simulation Lidar echo simulation DBNmodel GA-BP model Wakevortex characteristic parameter inversion model
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Self-heating tendency evaluation of sulfide ores based on nonlinear multi-parameters fusion 认领 引用 被引量：3
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作者 潘伟 吴超 +1 位作者 李孜军 杨月平 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第2期582-589,共8页
In order to reveal the nonlinear dynamics characteristics of unsteady self-heating process of sulfide ores, nine different kinds of sulfide ore samples from a pyrite mine in China were taken as experimental materials ... In order to reveal the nonlinear dynamics characteristics of unsteady self-heating process of sulfide ores, nine different kinds of sulfide ore samples from a pyrite mine in China were taken as experimental materials and their self-heating characteristics were measured in laboratory. Furthermore, the measured temperature was studied by integrating wavelet transform, nonlinear characteristic parameters extraction and fuzzy comprehensive evaluation. The results indicate that only the ore samples 1, 2, 6 and 9 have obvious self-heating phenomenon, and their self-heating initiative temperatures are 220 ℃, 239 ℃, 220 ℃ and 220 ℃, respectively, which means that they are difficult to produce self-heating under normal mining conditions. The correlation dimension of self-heating process is fraction and the maximum Lyapunov exponent is positive, which means that it is feasible to study the self-heating process based on chaotic dynamics theory. The nonlinearities of self-heating process of these four samples （ore samples 1, 2, 6 and 9） are 0.8227, 0.7521, 0.9401 and 0.8827 respectively and the order of the samples according to these results is： sample 6, sample 9, sample 1, sample 2, which is consistent with the measured results of self-heating characteristics. Therefore, the nonlinearity method can be used to evaluate the self-heating tendency of sulfide ores, and it is an effective verification of the reliability of measured results. 展开更多
关键词 sulfide ores self-heating process nonlinear characteristic parameter nonlinearity self-heating tendency
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