期刊文献+
共找到877,350篇文章
< 1 2 250 >
每页显示 20 50 100
Application of Matter-element Model in Soil Nutrient Evaluation of Ecological Fragile Region 被引量:2
1
作者 TANG Jie WANG Chenye +3 位作者 LIN Nianfeng LI Zhaoyang LI Haiyi MAO Zilong 《Chinese Geographical Science》 SCIE CSCD 2009年第2期168-176,共9页
On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN... On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN), total P (TP), total K (TK), available N (AN), available P (AP) and available K (AK) were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da'an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models. 展开更多
关键词 soil nutrient evaluation matter-element model extension engineering theory ecological fragile region
在线阅读 下载PDF
Carrying capacity of water environment in public tourism resources based on matter-element model 被引量:6
2
作者 XU Zi-lin YAN Wei 《Ecological Economy》 2016年第3期296-300,共5页
When water environmental carrying capacity of public resource tourist attraction is studied, the two action subjects of tourists and local residents should be discussed, and comprehensive consideration must be given t... When water environmental carrying capacity of public resource tourist attraction is studied, the two action subjects of tourists and local residents should be discussed, and comprehensive consideration must be given to the influence of these two on water environment. On the basis of water resource carrying capacity and water quality carrying capacity, water environmental carrying capacity index of public resource tourist attraction was constructed, the model for the water environmental carrying capacity of public resource tourist attraction was established on the basis of matter-element model and analytical hierarchy process. By applying this method, water environmental carrying capacity situation of a certain public resource tourist attraction can be gained, moreover, situations about several aspects of water environmental carrying capacity can be evaluated. 展开更多
关键词 matter-element model public tourism resources water environmental carrying capacity
在线阅读 下载PDF
Matter-element models for comprehensive earthquake predication and their applications 被引量:1
3
作者 蒋淳 陈化然 +1 位作者 田山 王建国 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第4期448-453,共6页
Extenics was a branch of mathematics for studying the incompatible problems. In this paper, basing on calculating the associative functions of all various indexes, we have obtained the quantitative assessment results ... Extenics was a branch of mathematics for studying the incompatible problems. In this paper, basing on calculating the associative functions of all various indexes, we have obtained the quantitative assessment results of prediction indexes by introducing this theory into the comprehensive earthquake prediction through establishing the matter-element model for comprehensive prediction, so that the incompatible problems can be solved. The preliminary results demonstrate that this method has better prospects in comprehensive earthquake prediction. 展开更多
关键词 EXTENICS comprehensive prediction model associative function anomaly index
在线阅读 下载PDF
River Health Assessment Based on Fuzzy Matter-element Model
4
作者 ZHANG You,LIU Ling,YAN Feng State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing,210098,China 《Meteorological and Environmental Research》 CAS 2011年第10期1-4,共4页
[Objective] The study aimed to assess the health state of rivers by using fuzzy matter-element model.[Method] Based on fuzzy matter-element analysis theory,the assessment model of river health was established,then a m... [Objective] The study aimed to assess the health state of rivers by using fuzzy matter-element model.[Method] Based on fuzzy matter-element analysis theory,the assessment model of river health was established,then a modified method to calculate the superior subordinate degree was put forward according to Hamming distance.Afterwards,a multi-level evaluation model,which contained the assessment indicators about hydrological features,ecological characteristics,environmental traits and service function,was set up based on this method above.Finally,the model was applied in the health assessment of Qinhuai River.[Result] The health state of Qinhuai River was at medium level.This assessment result was consistent with that of comprehensive index method,and it showed that the multi-level fuzzy matter-element model was effective in the assessment of river health.[Conclusion] The research provided an effective method to evaluate the state of river health. 展开更多
关键词 Fuzzy matter-element m odel River health ASSESSMENT China
在线阅读 下载PDF
The Research of Enterprise Finance Evaluation Based on Matter-element Model
5
作者 Li Pei zhe 《Journal of Zhouyi Research》 2014年第2期109-113,共5页
关键词 企业融资 物元模型 财务评价 盈利能力 评价方法 评价模型 财务状况 经营状况
在线阅读 下载PDF
Optimizing selection of bridge raft based on fuzzy matter-element model and combination weighting
6
作者 Li Feng Shao Fei +1 位作者 Wang Jianping Li Zhigang 《Engineering Sciences》 EI 2012年第1期61-64,96,共5页
It' s a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships. It is a comprehensive index for the scheme of bridge raft, containi... It' s a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships. It is a comprehensive index for the scheme of bridge raft, containing a variety of technical factors and uncertainties. The optimization is the selection in the constructing time, quantity of equipments and man power. Based on the calculation result of bridge rafts, an evaluating system is established, consisting of index of spacing between interior bays, raft length, truss numbers, operation difficulty and maximal bending stress. A fuzzy matter element model of optimizing selection of bridge rafts was built up by combining quantitative analysis with qualitative analysis. The method of combination weighting was used to calculate the value of weights index to reduce the subjective randomness. The sequence of schemes and the optimization resuh were gained finally based on euclid approach degree. The application result shows that it is simple and practical. 展开更多
关键词 bridge raft optimizing selection fuzzy matter-element combination weighting euclid approach degree
在线阅读 下载PDF
Comprehensive Benefit Evaluation Method of Mountain Flood Disaster Prevention and Control in Jiangxi Province Based on Matter-Element Extension Model
7
作者 Peixun Liu Yanbin Shao +3 位作者 Jiawen Ye Pingping Shi Dingbo Yuan Zhengwen Xu 《Journal of Geoscience and Environment Protection》 2024年第10期347-354,共8页
Taking the mountain flood disaster prevention and control project in Jiangxi province as the research object, the evaluation period is 2010-2015, and 29 evaluation indexes are selected from 7 aspects. In this paper, g... Taking the mountain flood disaster prevention and control project in Jiangxi province as the research object, the evaluation period is 2010-2015, and 29 evaluation indexes are selected from 7 aspects. In this paper, game theory is introduced to optimize the subjective and objective weights of the index, and the comprehensive weights are obtained by normalization. The results show that the eigenvalues of the grade variables of benefit evaluation decreased from 3.43 to 2.03, indicating that the project of mountain flood disaster prevention and control in Jiangxi province brings into play the benefits year by year, and the eigenvalues tend to decrease steadily after 2012, it is consistent with the changes of various engineering measures and non-engineering measures in the project. 展开更多
关键词 Index System Numerical model Comprehensive Evaluation
在线阅读 下载PDF
Evaluation of the eco-environmental frangibility in west Jilin Province based on the matter-element model
8
作者 Mingquan WANG Jinda WANG +1 位作者 Jingshuang LIU Jingxin DOU 《Frontiers in Biology》 CSCD 2008年第4期543-548,共6页
The west Jilin Province is a typical area in the ecotone between agriculture and animal husbandry,with a frangible eco-environment.With respect to the three aspects of water resource,natural disasters and land degrada... The west Jilin Province is a typical area in the ecotone between agriculture and animal husbandry,with a frangible eco-environment.With respect to the three aspects of water resource,natural disasters and land degradation,10 indices were selected to establish a matter-element model for the assessment of eco-environmental frangibility in the west Jilin Province.The results indicate that during 1985–2000,Qian’an,Fuyu,and Changling had the least frangibility(level Ⅰ),followed by Da’an and Qianguo(level Ⅱ),and Taobei,Zhenlai,Taonan,and Tongyu had the highest frangibility(level Ⅲ).On the whole,the counties in Songyuan city were less frangible than those in Baicheng city.Different counties had different frangibilities to environmental factors,e.g.,Da’an and Tongyu were frangible in water resource conditions;Taobei,Zhenlai,Taonan,Tongyu and Qian’an suffered most from natural disasters;while Taobei,Taonan and Qianguo were threatened by severe land degradation. 展开更多
关键词 matter-element model west Jilin Province frangibility entropy method
原文传递
Evaluation on Urban Land Ecological Security Based on the PSR Model and Matter-Element Analysis: A Case Study of Zhuhai, Guangdong, China 被引量:4
9
作者 LI Shuang 《Journal of Landscape Research》 2019年第3期82-88,92,共8页
As one of the Special Economic Zones since the reform and opening up, Zhuhai has developed during the past 30 years. Its economic development, industrial structure and ecological environment have undergone great chang... As one of the Special Economic Zones since the reform and opening up, Zhuhai has developed during the past 30 years. Its economic development, industrial structure and ecological environment have undergone great changes. Research on changes in Zhuhai’s land ecological security is of great significance. Using relevant data from 2007-2012, this study established a land ecological security assessment system based on the PSR conceptual framework model. The system contained 18 indicators from 3 aspects according to the concrete features of Zhuhai. Then we used the matterelement analysis and the improved entropy weight to analyze and evaluate the land ecological security of Zhuhai. The results showed that: from 2007 to 2012, the levels of the land ecological security of Zhuhai were “secure”, and the value increased year by year;as the land ecological security response value increased, Zhuhai was capable of solving land ecosystem problems. However, it should be noted that the structure of land ecosystem in Zhuhai has not formed and that rapid expansion of construction land has caused the shortage of cultivated land and other issues. Measures should be taken to control the construction area, improve land intensive utilization and improve the land ecological security. 展开更多
关键词 Land ECOLOGICAL security PSR model matter-element analysis Improved ENTROPY WEIGHT Zhuhai
在线阅读 下载PDF
Matter-elements model and application for prediction of ccoal and gas outburst 被引量:1
10
作者 PENG Shou-jian XU Jiang TAO Yun-qi CHENG Ming-jun 《Journal of Coal Science & Engineering(China)》 2009年第3期273-277,共5页
The theory and method of extenics were applied to establish classical field matterelements and segment field matter elements for coal and gas outburst.A matter-element model for prediction was established based on fiv... The theory and method of extenics were applied to establish classical field matterelements and segment field matter elements for coal and gas outburst.A matter-element model for prediction was established based on five matter-elements,which includedgas pressure,types of coal damage,coal rigidity,initial speed of methane diffusionand in-situ stress.Each index weight was given fairly and quickly through the improvedanalytic hierarchy process,which need not carry on consistency checks,so accuracy ofassessment can be improved. 展开更多
关键词 mining engineering coal and gas outburst PREDICTION matter-elements model relational degree
在线阅读 下载PDF
Evaluation model of venture investment based on fuzzy matter-element method of combined weight 被引量:5
11
作者 Meng Lin1 Bao Guangping2 Sun Yutao1(1 Department of Economics, Dalian University of Technology, Dalian 116024, China)(2 Finance and Taxation School, Northeast Finance and Economy University, Dalian 116025, China) 《Journal of Southeast University(English Edition)》 EI CAS 2008年第S1期27-32,共6页
An evaluation model of an international venture investment project on the basis of fuzzy matter-element and combined weight methods is introduced. First, the compound fuzzy matter-element of optimal subordinate degree... An evaluation model of an international venture investment project on the basis of fuzzy matter-element and combined weight methods is introduced. First, the compound fuzzy matter-element of optimal subordinate degree is constructed on the principle of the bigger-more-optimal or the less-more-optimal depending on the actual evaluation indicators, and combined with standard fuzzy matter-element to form a difference-square fuzzy matter-element. Secondly, a combined weight is calculated by both information entropy and the expert grading method. Finally, the compound fuzzy matter-element of Euclidian approach degree by M(·,+)method is constituted and used to classify venture investment projects. Based on the model above, six venture investment projects in a company are evaluated, and the results show that the projects are all good, which is demonstrated by the good income of the projects. Therefore, the coincidence of evaluation results and actual operation status indicates that the model is of great value in practical application. 展开更多
关键词 combined weights fuzzy matter-element venture investment
在线阅读 下载PDF
MATTER-ELEMENT MODELING OF PARALLEL STRUCTURE AND APPLICATION ABOUT EXTENSION PID CONTROL SYSTEM 被引量:3
12
作者 Rongde LU Zonghai CHEN 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2006年第2期227-235,共9页
This article describes in detail a new method via the extension predictable algorithm of the matter-element model of parallel structure tuning the parameters of the extension PID controller. In comparison with fuzzy a... This article describes in detail a new method via the extension predictable algorithm of the matter-element model of parallel structure tuning the parameters of the extension PID controller. In comparison with fuzzy and extension PID controllers, the proposed extension PID predictable controller shows higher control gains when system states are away from equilibrium, and retains a lower profile of control signals at the same time. Consequently, better control performance is achieved. Through the proposed tuning formula, the weighting factors of an extension-logic predictable controller can be systematically selected according to the control plant. An experimental example through industrial field data and site engineers' experience demonstrates the superior performance of the proposed controller over the fuzzy controller. 展开更多
关键词 Extension control system matter modeling parallel structure PID predictable algorithm.
原文传递
Expert Anti-Evaluation Model Based on Matter-Element Analysis in Fund Project Peer-Review System
13
作者 Haifeng Li Yanzhong Dang 《Intelligent Information Management》 2010年第3期227-231,共5页
The article analyses several key issues which restrict the effectiveness of fund project peer review work. It analyses the evaluating theory and matter-element theory to access the expert anti-evaluation model, and al... The article analyses several key issues which restrict the effectiveness of fund project peer review work. It analyses the evaluating theory and matter-element theory to access the expert anti-evaluation model, and also studies the expert anti-evaluation index system to support the anti-evaluation method. The practical basis is the true score data of the experts which is collected from the actual anti-evaluation in Liaoning province science and technology fund project peer review system. With the practical experience of the actual project, we prove that the expert index system anti-evaluation model and expert anti-evaluation method can improve the fund project peer review work and play a positive role for the peer review work and also make the review work more scientific and more rational. 展开更多
关键词 Anti-Evaluation model matter-element Analysis Index SYSTEM Comprehensive Evaluation PEER Review
在线阅读 下载PDF
Comparative analysis of empirical and deep learning models for ionospheric sporadic E layer prediction
14
作者 BingKun Yu PengHao Tian +6 位作者 XiangHui Xue Christopher JScott HaiLun Ye JianFei Wu Wen Yi TingDi Chen XianKang Dou 《Earth and Planetary Physics》 EI CAS 2025年第1期10-19,共10页
Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 km.Because they can significantly influence radio communications and navigation systems,... Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 km.Because they can significantly influence radio communications and navigation systems,accurate forecasting of Es layers is crucial for ensuring the precision and dependability of navigation satellite systems.In this study,we present Es predictions made by an empirical model and by a deep learning model,and analyze their differences comprehensively by comparing the model predictions to satellite RO measurements and ground-based ionosonde observations.The deep learning model exhibited significantly better performance,as indicated by its high coefficient of correlation(r=0.87)with RO observations and predictions,than did the empirical model(r=0.53).This study highlights the importance of integrating artificial intelligence technology into ionosphere modelling generally,and into predicting Es layer occurrences and characteristics,in particular. 展开更多
关键词 ionospheric sporadic E layer radio occultation ionosondes numerical model deep learning model artificial intelligence
在线阅读 下载PDF
Evaluation of Social Environment Impact of Highway Construction Using Gray Matter-Element Information Entropy Model
15
作者 C.K. Hu 《Journal of Environmental Science and Engineering》 2011年第12期1688-1694,共7页
Due to the importance of the social environment impact of highway construction project, an advanced evaluation is required to incorporate situations such as uncertainty, incompatibility and less information. This pape... Due to the importance of the social environment impact of highway construction project, an advanced evaluation is required to incorporate situations such as uncertainty, incompatibility and less information. This paper proposes a gray matter-element evaluation model based on the information entropy. The model is developed by combining both quantitative and qualitative methods, using probability theory to convert quantitative index to qualitative index, and the weight of those indexes were determined through synthesised integral weighting method, integrating matter-element theory, grey theory, and information theory. The model is then applied to evaluate the impact of the social environmental impact of highway construction project which will provide support for decision makers. Cheng-Yu highway and Shen-Da highway were selected for model application, and good results were achieved similar to the real situation. 展开更多
关键词 Project evaluation social environment gray matter-element assessment.
在线阅读 下载PDF
Dynamics of a Stochastic Epidemic Model with Age-group
16
作者 LAN Xiaomin CHEN Guangmin +5 位作者 ZHOU Ruiyang ZHENG Kuicheng CAI Shaojian WEI Fengying JIN Zhen MAO Xuerong 《应用数学》 北大核心 2025年第1期294-307,共14页
A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,t... A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases. 展开更多
关键词 Epidemic model Age groups PERSISTENCE EXTINCTION
在线阅读 下载PDF
3D crustal density modeling of Egypt using GOCE satellite gravity data and seismic integration 被引量:1
17
作者 Moataz Sayed Mohamed Sobh +2 位作者 Salah Saleh Amal Othman Ahmed Elmahmoudi 《Earthquake Science》 2025年第2期110-125,共16页
A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques inclu... A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques include obtaining gravity data from the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE),creating seismic profiles,analyzing the receiver functions of seismic data,obtaining information from boreholes,and providing geological interpretations.GOCE satellite gravity data were processed to construct a preliminary model based on nonlinear inversions of the data.A regional crustal thickness model was developed using receiver functions,seismic refraction profiles,and geological insights.The inverted model was validated using borehole data and compared with seismic estimates.The model exhibited strong consistency and revealed a correlation between crustal thickness,geology,and tectonics of Egypt.It showed that the shallowest depths of the Moho are located in the north along the Mediterranean Sea and in the eastern part along the Red Sea,reflecting an oceanic plate with a thin,high-density crust.The deepest Moho depths are located in the southwestern part of Egypt,Red Sea coastal mountains,and Sinai Peninsula.The obtained 3D model of crustal thickness provided finely detailed Moho depth estimates that aligned closely with geology and tectonic characteristics of Egypt,contributing valuable insights into the subsurface structure and tectonic processes of region. 展开更多
关键词 GOCE satellite gravity Moho depth crustal modeling gravity inversion
在线阅读 下载PDF
Aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders:progress of experimental models based on disease pathogenesis
18
作者 Li Xu Huiming Xu Changyong Tang 《Neural Regeneration Research》 SCIE CAS 2025年第2期354-365,共12页
Neuromyelitis optica spectrum disorders are neuroinflammatory demyelinating disorders that lead to permanent visual loss and motor dysfunction.To date,no effective treatment exists as the exact causative mechanism rem... Neuromyelitis optica spectrum disorders are neuroinflammatory demyelinating disorders that lead to permanent visual loss and motor dysfunction.To date,no effective treatment exists as the exact causative mechanism remains unknown.Therefore,experimental models of neuromyelitis optica spectrum disorders are essential for exploring its pathogenesis and in screening for therapeutic targets.Since most patients with neuromyelitis optica spectrum disorders are seropositive for IgG autoantibodies against aquaporin-4,which is highly expressed on the membrane of astrocyte endfeet,most current experimental models are based on aquaporin-4-IgG that initially targets astrocytes.These experimental models have successfully simulated many pathological features of neuromyelitis optica spectrum disorders,such as aquaporin-4 loss,astrocytopathy,granulocyte and macrophage infiltration,complement activation,demyelination,and neuronal loss;however,they do not fully capture the pathological process of human neuromyelitis optica spectrum disorders.In this review,we summarize the currently known pathogenic mechanisms and the development of associated experimental models in vitro,ex vivo,and in vivo for neuromyelitis optica spectrum disorders,suggest potential pathogenic mechanisms for further investigation,and provide guidance on experimental model choices.In addition,this review summarizes the latest information on pathologies and therapies for neuromyelitis optica spectrum disorders based on experimental models of aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders,offering further therapeutic targets and a theoretical basis for clinical trials. 展开更多
关键词 AQUAPORIN-4 experimental model neuromyelitis optica spectrum disorder PATHOGENESIS
在线阅读 下载PDF
Modeling and sliding mode control based on inverse compensation of piezo-positioning system
19
作者 LI Zhi-bin XIN Yuan-ze +1 位作者 ZHANG Jian-qiang SUN Chong-shang 《中国光学(中英文)》 北大核心 2025年第1期170-185,共16页
In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis... In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis nonlinear characteristics of piezo-positioning actuator.The static nonlinear part and dynamic linear part of the Hammerstein model are represented by models obtained through the Prandtl-Ishlinskii(PI)model and Hankel matrix system identification method,respectively.This model demonstrates good generalization capability for typical input frequencies below 200 Hz.A sliding mode inverse compensation tracking control strategy based on P-I inverse model and integral augmentation is proposed.Experimental results show that compared with PID inverse compensation control and sliding mode control without inverse compensation,the sliding mode inverse compensation control has a more ideal step response and no overshoot,moreover,the settling time is only 6.2 ms.In the frequency domain,the system closed-loop tracking bandwidth reaches 119.9 Hz,and the disturbance rejection bandwidth reaches 86.2 Hz.The proposed control strategy can effectively compensate the hysteresis nonlinearity,and improve the tracking accuracy and antidisturbance capability of piezo-positioning system. 展开更多
关键词 piezo-positioning system hysteresis nonlinearity Hammerstein model Prandtl-Ishlinskii(P-I)model system identification sliding mode control
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部