期刊文献+
共找到11,496篇文章
< 1 2 250 >
每页显示 20 50 100
Exploring the Goal Synergy between the Ecological Carrying Capacity of Miyun District and the Development of the Ecological Home-stay Industry in Beijing
1
作者 ZHANG Qilun CAO Jinglong XU Zhiyong 《Journal of Landscape Research》 2023年第2期45-48,53,共5页
Green construction in culture and environmental protection will be the development trend in a long run,the urban and suburban area will be ecologically developed as well.Rural revitalization must adhere to the positio... Green construction in culture and environmental protection will be the development trend in a long run,the urban and suburban area will be ecologically developed as well.Rural revitalization must adhere to the position of historical progress theory and modern concepts,innovate spatial layout,optimize ecological resources,and appropriately determine its historical significance and sustainable development responsibility with reasonable value orientation and environmental ecological carrying capacity for local ecological construction.In order to achieve this responsibility,the authors must expand the dimensions to consider more relevant factors.The guarantee of ecological carrying capacity is an important means to ensure the promotion of ecological civilization.This paper aims to integrate and regulate the goal synergy of the cultural development of the home-stay industry in Miyun District of Beijing by means of the innovative model of sustainable economic development of cultural ecology,ecological people,ecological health preservation and rich home-stay ecological elements.Assuming that the role of the former in promoting the latter can be expanded,then in the range of ecological and cultural towns(conceptual model)that maintain a certain tolerance of ecological carrying capacity,as a characteristic home-stay industry in Miyun,there will be some effective growth,so the integration and development of multiple cultural genes and elements must be the ecological and cultural town model under the enhanced multi-factor aggregation effect,(See the ecological environment carrying capacity development goal A:A=B12345+C1234567 later).This article will explain that the development goals of Miyun's ecological culture and the ecological homestay industry are coordinated,and the two are mutually raised in the same direction. 展开更多
关键词 ecological carrying capacity Coordinated development goals of ecological home-stay industry Goal synergy
下载PDF
Bending Failure Mode and Prediction Method of the Compressive Strain Capacity of A Submarine Pipeline with Dent Defects
2
作者 HOU Fu-heng JIA Lu-sheng +3 位作者 CHEN Yan-fei ZHANG Qi ZHONG Rong-feng WANG Chun-sha 《China Ocean Engineering》 SCIE EI CSCD 2024年第4期636-647,共12页
A dent is a common type of defects for submarine pipeline.For submarine pipelines,high hydrostatic pressure and internal pressure are the main loads.Once pipelines bend due to complex subsea conditions,the compression... A dent is a common type of defects for submarine pipeline.For submarine pipelines,high hydrostatic pressure and internal pressure are the main loads.Once pipelines bend due to complex subsea conditions,the compression strain capacity may be exceeded.Research into the local buckling failure and accurate prediction of the compressive strain capacity are important.A finite element model of a pipeline with a dent is established.Local buckling failure under a bending moment is investigated,and the compressive strain capacity is calculated.The effects of different parameters on pipeline local buckling are analyzed.The results show that the dent depth,external pressure and internal pressure lead to different local buckling failure modes of the pipeline.A higher internal pressure indicates a larger compressive strain capacity,and the opposite is true for external pressure.When the ratio of external pressure to collapse pressure of intact pipeline is greater than 0.1,the deeper the dent,the greater the compressive strain capacity of the pipeline.And as the ratio is less than 0.1,the opposite is true.On the basis of these results,a regression equation for predicting the compressive strain capacity of a dented submarine pipeline is proposed,which can be referred to during the integrity assessment of a submarine pipeline. 展开更多
关键词 submarine pipeline dent defect bending load local buckling compressive strain capacity
下载PDF
Optimal Design of the Modular Joint Drive Train for Enhancing Cobot Load Capacity and Dynamic Performance
3
作者 Peng Li Zhenguo Nie +1 位作者 Zihao Li Xinjun Liu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期26-40,共15页
Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to e... Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more flexible.In this paper,a new method for designing the drive train parameters of cobot is proposed.Firstly,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design domain.Secondly,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design variables.Finally,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective optimization.Base on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial cobot.The result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a benchmark.The minimum resonance frequency of the joints is 42.70 Hz. 展开更多
关键词 Multi-objective optimization Modular joint drive train design Load capacity Dynamic response performance
下载PDF
Analysis of the Application of Static Load Test in Bridge Bearing Capacity Testing
4
作者 Wei Fu Bo Liu 《Journal of Architectural Research and Development》 2024年第3期36-41,共6页
This article uses real engineering projects as examples to analyze how static load test technology is applied in testing the bridge-bearing capacity.The analysis covers aspects such as testing section layout,test load... This article uses real engineering projects as examples to analyze how static load test technology is applied in testing the bridge-bearing capacity.The analysis covers aspects such as testing section layout,test load and efficiency coefficient,loading plan,evaluation optimization,test result modification,and result evaluation.The aim is to support the accurate detection and evaluation of bridge-bearing capacity. 展开更多
关键词 Bridge engineering Bearing capacity Static load test loading plan Test evaluation
下载PDF
Quantitative Research on Ecological Compensation among Every City of Guangdong Province Based on Ecological Footprint and Ecological Carrying Capacity 被引量:9
5
作者 刘强 彭晓春 +1 位作者 周丽旋 张杏杏 《Meteorological and Environmental Research》 CAS 2010年第6期82-85,共4页
Based on the relative theories and methods of ecological footprint and ecological carrying capacity,and according to practical conditions of Guangdong Province,this paper tried to put forward the determinant standard ... Based on the relative theories and methods of ecological footprint and ecological carrying capacity,and according to practical conditions of Guangdong Province,this paper tried to put forward the determinant standard for ecological compensation through calculating the ecological footprint and ecological carrying capacity of every city in Guangdong Province. The results indicated that the ecological footprint of each city was in the status of deficit and the deficit level decreased gradually from developed regions of Pearl River Delta to the outlying regions. The cities which belonged to development areas of Pearl River Delta needed to pay ecological compensation,such as Guangzhou and Shenzhen and so on. In contrast,the cities which accepted compensation were underdeveloped areas,such as Heyuan and Jieyuan and so on. 展开更多
关键词 ecological footprint ecological carrying capacity ecological compensation Guangdong Province China
下载PDF
Dynamic Changes of Land Ecological Carrying Capacity Based on the Ecological Footprint——By the Case Study of Chengdu City 被引量:4
6
作者 彭文甫 钟小兰 +1 位作者 黎秋阳 李琴 《Agricultural Science & Technology》 CAS 2012年第9期1986-1990,共5页
Chengdu City is in the period of rapid urbanization and industrialization, and the disturbance derived from human activities on environment is increasing remarkablely in recent 20 years. The pressure on environment, e... Chengdu City is in the period of rapid urbanization and industrialization, and the disturbance derived from human activities on environment is increasing remarkablely in recent 20 years. The pressure on environment, economy and population is also increasing and land use in Chengdu has changed enormously. As struc- ture and function of land ecological system change obviously, sustainable development of land productivity has been an important goal and strategic task from now on, and it is necessary to systematically research land ecological carrying capacity based on ecological footprint. The ecological footprint of Chengdu City in the past ten years was calculated and analyzed from the spatial and temporal aspects according to statistical data from 1998 to 2008, as per ecological footprint method, ecological carrying capacity and the GIS spatial analysis method, and regression analysis method. The ecological footprint and ecological carrying capacity values from 2009 to 2019 in Chengdu City were predicted through calculation results in the past ten years. The results show that the ecological footprint and ecological deficit of land use from 1998 to 2008 increased in Chengdu City. The ecological deficit of land use within the city center was in high levels in the past ten years, and the ecological footprint kept raising, especially in areas, such as Shuangliu, Chongzhou, Qingyang among 9 city areas, 4 counties and 6 districts in Chengdu City. There is fanlike distribution of ecological deficit of land use. Analysis shows that the social and natural ecological system is uneven distribution, which is not in sustainable de- velopment situation. The results of the study show that the economic, social and natural ecological system in Chengdu City is not sustainable, and the ecological foot- print is uneven distribution. The analysis of the dynamic change of land ecological carrying capacity in Chengdu City is very important for city government in the pro- cess of the vigorous development in new Tianfu Xinqu, and redevelopment in the northern part of this city. 展开更多
关键词 ecological footprint ecological carrying capacity Chengdu City Sustain-able development
下载PDF
Ecological Carrying Capacity in Beijing Mountainous Areas——Taking Fangshan District as an Example 被引量:3
7
作者 穆松林 张义丰 +2 位作者 唐承财 王灵恩 刘玉 《Agricultural Science & Technology》 CAS 2012年第11期2429-2433,共5页
[Objective] The aim was to investigate ecological carrying capacity of Fangshan District in Beijing. [Method] Ecological footprint and carrying capacity of Fangshan District in 2007 and 2008 were analyzed with ecologi... [Objective] The aim was to investigate ecological carrying capacity of Fangshan District in Beijing. [Method] Ecological footprint and carrying capacity of Fangshan District in 2007 and 2008 were analyzed with ecological footprint model and the difference between ecological footprint and carrying capacity there was con- cluded. Furthermore, an assessment was made on relation between Fangshan de- velopment with local ecological carrying capacity to evaluate sustainable development of Fangshan District. [Result] Fangshan District is of lightly ecological deficit; ecologi- cal footprint per capita in 2007-2008 was deficit and tended to expand. Two meth- ods are available to reduce ecological :deficit, including reduction of ecological foot- print and increase of carrying capacity. In general, supply and demand of carrying capacity in Fangshan are better, though with some problems. It is necessary to fur- ther develop related industries to final eliminate ecological deficit in order to achieve ecological conservation-orientation and sustainable development of Fangshan District. [Conclusion] The research provides theoretical references for overall evaluation on eco- logical carrying capacity of Fangshan District. 展开更多
关键词 Mountainous areas in Beijing ecological carrying capacity FangshanDistrict
下载PDF
The calculation and analysis of ecological footprints,diversity and developm ent capacity of China 被引量:15
8
作者 XUZhongmin CHENGGuodong +2 位作者 ZHANGZhiqiang PaulHTemplet YongyuanYIN 《Journal of Geographical Sciences》 SCIE CSCD 2003年第1期19-26,共8页
T he ecological footprint of China's provinces is calculated in this pap er. In general, China's development is not sustainable because its ecological footprint is beyond its bio-capacity. The sustainability s... T he ecological footprint of China's provinces is calculated in this pap er. In general, China's development is not sustainable because its ecological footprint is beyond its bio-capacity. The sustainability status of each pr ovince in China is presented. Ulanowicz's development capacity formula w as introduced to discuss the relationship of development and ecological footprin t's diversity. The diversity of ecological impacts is related to the e fficiency with which an economy uses the source and sink services of the environment and, in this view, should be a factor in economic output. Developme nt capacity, calculated from the ecological footprint and its diversity , is used to examine the relationship of economic output with the st ructure of the ecological footprint. China and its provinces are prese nted as a case study to investigate this relationship. The analysis s hows that footprint capacity is significant in predicting economic outp ut. Increasing the ecological footprint's diversity is presented as another way to increase development capacity. 展开更多
关键词 ecological footprints DIVERSITY development capacity China
下载PDF
Influence of Particles on the Loading Capacity and the Temperature Rise of Water Film in Ultra-high Speed Hybrid Bearing 被引量:3
9
作者 ZHU Aibin LI Pei +2 位作者 ZHANG Yefan CHEN Wei YUAN Xiaoyang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第3期541-548,共8页
Ultra-high speed machining technology enables high efficiency, high precision and high integrity of machined surface. Previous researches of hybrid bearing rarely consider influences of solid particles in lubricant an... Ultra-high speed machining technology enables high efficiency, high precision and high integrity of machined surface. Previous researches of hybrid bearing rarely consider influences of solid particles in lubricant and ultra-high speed of hybrid bearing, which cannot be ignored under the high speed and micro-space conditions of ultra-high speed water-lubricated hybrid bearing. Considering the impact of solid particles in lubricant, turbulence and temperature viscosity effects of lubricant, the influences of particles on pressure distribution, loading capacity and the temperature rise of the lubricant film with four-step-cavity ultra-high speed water-lubricated hybrid bearing are presented in the paper. The results show that loading capacity of the hybrid bearing can be affected by changing the viscosity of the lubricant, and large particles can improve the bearing loading capacity higher. The impact of water film temperature rise produced by solid particles in lubricant is related with particle diameter and minimum film thickness. Compared with the soft particles, hard particles cause the more increasing of water film temperature rise and loading capacity. When the speed of hybrid bearing increases, the impact of solid particles on hybrid bearing becomes increasingly apparent, especially for ultra-high speed water-lubricated hybrid bearing. This research presents influences of solid particles on the loading capacity and the temperature rise of water film in ultra-high speed hybrid bearings, the research conclusions provide a new method to evaluate the influence of solid particles in lubricant of ultra-high speed water-lubricated hybrid bearing, which is important to performance calculation of ultra-high speed hybrid bearings, design of filtration system, and safe operation of ultra-high speed hybrid bearings. 展开更多
关键词 hybrid bearing liquid-solid flow solid particles loading capacity temperature rise
下载PDF
Undrained Bearing Capacity of Spudcan Under Combined Loading 被引量:2
10
作者 王立忠 舒恒 +1 位作者 李玲玲 国振 《China Ocean Engineering》 SCIE EI 2011年第1期15-30,共16页
The bearing capacities of spudcan foundation under pure vertical (/1), horizontal (H), moment (M) loading and the combined loading are studied based on a series of three-dimensional finite element analysis. The ... The bearing capacities of spudcan foundation under pure vertical (/1), horizontal (H), moment (M) loading and the combined loading are studied based on a series of three-dimensional finite element analysis. The effects of embedment ratio and soil non-homogeneity on the bearing capacity are investigated in detail. The capacities of spudcan under different pure loading are expressed in non-dimensional bearing capacity factors, which are compared with published results. Ultimate limit states under combined loading are presented by failure envelopes, which are expressed in terms of dimensionless and normalized form in three-dimensional load space. The comparison between the presented failure envelopes and available published numerical results reveals that the size and shape of failure envelopes are dependent on the embedment ratio and the non-homogeneity of the soil. 展开更多
关键词 soft clay SPUDCAN bearing capacity combined loading finite element
下载PDF
Evaluation of Ecological Carrying Capacity of Henan Province under the Sustainable Development 被引量:3
11
作者 JIANG Xiao-ping 《Asian Agricultural Research》 2010年第6期60-64,共5页
Based on the overview of social economy of Henan Province,I probe into the concept and evaluation of ecological carrying capacity.By using the ecological footprint analysis and the data of various kinds of land supply... Based on the overview of social economy of Henan Province,I probe into the concept and evaluation of ecological carrying capacity.By using the ecological footprint analysis and the data of various kinds of land supply of Henan Province from 2000 to 2008,the ecological carrying capacity of Henan Province is analyzed.It is unveiled that inharmonious population,natural resources and economic resources affect the efficiency of the sustainable development of ecological carrying capacity of Henan Province;the underdeveloped economy of Henan Province impacts the sustainable development of ecological carrying capacity of Henan Province and the overburdened population lead to the insufficiency of ecological carrying capacity.Around protecting the threshold of ecological system,the countermeasures are put forward,which cover forming the idea of ecological economy and circular economy and promoting the transformation of economy growth mode;taking the development road of using resources intensively and performing the strategy of sustainable utilization of resources;strictly control population growth and strengthening people's crisis awareness of resources and environment. 展开更多
关键词 ecological carrying capacity ecological footprint analysis THRESHOLD Henan Province China
下载PDF
Quantitative Appraisement on Ecological Carrying Capacity in Coastal Rapid Developing Region of Hainan Province 被引量:3
12
作者 Zhang Fugang Liu Yansui 《Chinese Journal of Population,Resources and Environment》 北大核心 2008年第2期87-92,共6页
The ecological carrying capacity,an important indica- tor to evaluate the sustainable development of the ecosystem, means the potential ability of the natural ecosystem to carry so- cioeconomic development while the e... The ecological carrying capacity,an important indica- tor to evaluate the sustainable development of the ecosystem, means the potential ability of the natural ecosystem to carry so- cioeconomic development while the ecosystem is healthy.It is limited by the carrying capacity of natural resources and environ- ment and the elasticity of the ecosystem.It will be greatly signifi- cant to study the ecological carrying capacity of Hainan Province, the first ecological province admitted by the State Environmental Protection Administration in China.Not only is the natural eco- system reflected,but also the effects of human activities are em- phasized by integrating the ecosystem health analysis into the ecological carrying capacity research.The research results,using the Factor Analysis tools of software SPSS,indicate that the eco- logical carrying capacity of Hainan Province fluctuated obviously from 1996 to 2005.The level of the ecological carrying capacity of Hainan Province was relatively high in 1996,and reached into trough from 1997 to 1999.It has steadily ascended to be above the middle level since the 21st century.The results also show that policy factors,especially the implementation of the 'Ecological Province' strategy,were important driving forces to influence the ecological carrying capacity.With the population rapidly increas- ing,the land and water resources per capita have decreased quickly.The amount of the ecological carrying capacity was pro- moted remarkably by socioeconomic development especially economic growth and technology applications.All of these will provide useful suggestions to establish and enact regional devel- opment policies,especially for protecting and reconstructing the ecology and environment of Hainan Province. 展开更多
关键词 ecological carrying capacity evaluation driving forces Hainan Province
下载PDF
Effect of regional ecological carrying capacity on economic transformation 被引量:1
13
作者 WANG Shuo HU Zhen-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第6期1522-1528,共7页
Combined with the actual situation of the western region city of Zunyi, the three subsystems including social, economic and natural environment evaluation index systems of ECC have been built based on the theory of ec... Combined with the actual situation of the western region city of Zunyi, the three subsystems including social, economic and natural environment evaluation index systems of ECC have been built based on the theory of ecological carrying capacity(ECC). In addition, the factor analysis method has been used and the influence factors on the ECC in the economic transition have been gained. The results show that factors of ECC in the three subsystems have different influence: 1) the natural subsystem, which contains factors on the ECC, has obvious limitation, and it has the greatest influence on industrial waste discharge per capita; 2) the social subsystem has a restriction on the ECC, which affects the traffic environment mostly; 3) the economic subsystem has a certain restriction on ECC, which has a large effect on the consumption level per capita. 展开更多
关键词 ECONOMIC TRANSITION ecological carrying capacity (ECC) FACTOR analysis Chinese WESTERN region environmental engineering
下载PDF
Capacity Maximization Based Power Loading Analysis for Digital Channelized Satcom Systems 被引量:2
14
作者 YAN Jian CHEN Xiang LIU Chunli 《China Communications》 SCIE CSCD 2015年第5期64-74,共11页
For digital channelized frequency division multiple access based satellite communication(SATCOM) systems,it is a challenging but critical issue to improve the transponder power and spectrum efficiency simultaneously u... For digital channelized frequency division multiple access based satellite communication(SATCOM) systems,it is a challenging but critical issue to improve the transponder power and spectrum efficiency simultaneously under limited and non-linear high-power amplifier conditions.In this paper,different from the traditional link supportability designs aiming at minimizing the total transponder output power,a maximal sum Shannon capacity optimization objective is firstly raised subject to link supportability constraints.Furthermore,an efficient multilevel optimization(MO) algorithm is proposed to solve the considered optimization problem in the case of single link for each terminal.Moreover,in the case of multiple links for one terminal,an improved MO algorithm involving Golden section and discrete gradient searching procedures is proposed to optimize power allocation over all links.Finally,several numerical results are provided to demonstrate the effectiveness of our proposals.Comparison results show that,by the MO algorithm,not only all links' supportability can be guaranteed but also a larger sum capacity can be achieved with lower complexity. 展开更多
关键词 capacity maximization power loading multilevel optimization digital channelized satellite
下载PDF
Ecological Carrying Capacity of Shennongjia Based on Sustainable Development 被引量:1
15
作者 ZHAO Liya CHEN Tao +2 位作者 CHENG Chang ZHANG Wenna JIANG Liping 《Journal of Landscape Research》 2016年第1期18-22,共5页
Ecological carrying capacity is a significant index for measuring sustainability of natural resources in a region. This paper applied ecological footprint counting model to calculate ecological footprint and ecologica... Ecological carrying capacity is a significant index for measuring sustainability of natural resources in a region. This paper applied ecological footprint counting model to calculate ecological footprint and ecological carrying capacity of the typical resource-based city—Shennongjia from 2008 to 2012. The results showed that(a) ecological footprint and per capita ecological footprint in Shennongjia area increased from 86,464.48 ha and 1.076 ha. in 2008 to 93,13.59 ha. and 1.171 ha. in 2012;(b) total ecological carrying capacity, and per capita ecological carrying capacity fluctuated, and total ecological carrying capacity > total ecological footprint, per capita ecological carrying capacity > total ecological footprint, thus it had ecological surplus;(c) among all land use types, water resources had the largest ecological surplus, construction land and woodland had the second and third largest; waters and fossil energy land showed ecological deficit and needed outer supply. As a whole, Shennongjia area had an excellent ecological environment with less destruction and good sustainability. 展开更多
关键词 Sustainable development ecological carrying capacity ecological footprint Shennongjia
下载PDF
Ecological Carrying Capacity Prediction of Huainan City Based on GM–BP Neural Network 被引量:1
16
作者 LI Jiulin GU Kangkang +2 位作者 CHU Jinlong JIANG Benchuan ANG Lin 《Journal of Landscape Research》 2016年第1期35-40,共6页
Evaluation of ecological carrying capacity is an important method of analyzing regional sustainable development, study on ecological carrying capacity is to settle the contradictions between resource and environment, ... Evaluation of ecological carrying capacity is an important method of analyzing regional sustainable development, study on ecological carrying capacity is to settle the contradictions between resource and environment, and it is a significant basis for realizing regional sustainable development. This paper, on the basis of the academician Sun Tiehang's "unification of three" for the eco-city construction, established ecological carrying capacity evaluation indexes for the traditional industrial and mining city—Huainan City; and applied GM–BP neural network coupling model for the dynamic evolution and prediction of ecological carrying capacity of Huainan City in the future decade. The results showed that ecological carrying capacity index of Huainan would be 2.13 by 2025, higher than the loadable state 1, so the ecological carrying capacity would keep in the over-loaded level, but the over-loaded degree would be lower than the current. Carrying capacity of arable land, energy and water resources contribute greatly to the improvement of ecological carrying capacity, thus it is imperative to adjust this unreasonable and unsustainable ecological consumption relationship, enhance environmental protection awareness and high-efficiency utilization of resources, and take an energy-saving and intensive development path. 展开更多
关键词 ecological carrying capacity GM(1 1) BP neural network Coupling model PREDICTION
下载PDF
Safety Evaluation of Water Environment Carrying Capacity of Five Cities in Ningxia Based on Ecological Footprint of Water Resources 被引量:1
17
作者 Chang LU Rui XI +1 位作者 Zhengjun HEI Lian TANG 《Asian Agricultural Research》 2022年第5期11-16,共6页
[Objectives]To make safety evaluation of water environment carrying capacity of five cities in Ningxia based on ecological footprint of water resources.[Methods]With the help of the grey relational model,15 indicators... [Objectives]To make safety evaluation of water environment carrying capacity of five cities in Ningxia based on ecological footprint of water resources.[Methods]With the help of the grey relational model,15 indicators were selected from the natural,economic,and social aspects,and the most influential factors in the three fields were selected.Based on the concept of ecological priority,the water resources carrying capacity of the five cities in Ningxia from 2010 to 2019 was calculated with the help of the water resources ecological footprint model.Then,the indicators of the water resources ecological footprint model were coupled with the existing indicators to establish a comprehensive evaluation indicator system.Finally,the changes of the water environment carrying capacity of the five cities in Ningxia were analyzed with the help of the principal component analysis(PCA).[Results]The ecological pressure of water resources and the ecological deficit of water resources in the five cities were relatively large.Specifically,Yinchuan City had the most obvious deficit of water resources but good carrying capacity;Zhongwei City had a large ecological deficit of water resources,poor carrying capacity,and the largest ecological pressure index of water resources;Guyuan City had low water resources ecological deficit,water resources ecological carrying capacity and water resources ecological pressure index.[Conclusions]Through the analysis of the coupling indicator system,it can be seen that the water environment carrying capacity of the five cities is in an upward trend,indicating that the water environment in each region tends to become better. 展开更多
关键词 Water environment carrying capacity Grey relation analysis(GRA) Principal component analysis(PCA) Water resources ecological footprint Influencing factors
下载PDF
The Loading Capacity of the Elands River: A Case Study of the Waterval Boven Wastewater Treatment Works, Mpumalanga Province, South Africa
18
作者 Sandile Dlamini Thomas K. Gyedu-Ababio Andrew Slaughter 《Journal of Water Resource and Protection》 2019年第8期1049-1063,共15页
Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the p... Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the pollution load into the Elands River in terms of nitrates and orthophosphates. These variables were compared against the Crocodile Catchment Interim Resource Quality Objectives to determine compliances or non-compliance of the Waterval Boven wastewater treatment plant. Generally upstream nitrate levels did not exceed the ideal limit of 0.5 mg·l-1 as indicated in the 2015 to 2016 samples where values ranged between 0.32 mg·l -1 and 0.27 mg·l-1, respectively. Similarly, observed upstream orthophosphates levels were below the ideal limit of 0.03 mg·l-1. However, downstream values of both nutrients exceeded the respective set limits. The nutrient load contribution from the sewage plant was characterised by a simple point-source model. Patterns of the loads into the river were demonstrated on a load duration curve based on the river which equalled or exceed 0.18 m3/s upstream and 1.31 m3/s downstream at 90% of the time. However, the flows were regarded as significantly low to deal with uncontrolled pollution loads. Most of the observed loads fell below the ideal limit of 0.05 mg·l-1 for nitrates both upstream and downstream of the sewage plant. For orthophosphates, most of the upstream loads were below the tolerable limit of 0.1 mg·l-1 whilst the downstream loads were exceeding the tolerable limits. The higher loads downstream in the river were attributed to the sewage discharge from the Waterval Boven wastewater treatment plant and the low river flows. Hence it could be concluded that river water quality should be interpreted based on the river flow regime in a given season. 展开更多
关键词 loading capacity Flow DURATION CURVE Load DURATION CURVE EXCEEDANCE
下载PDF
Ecological Carrying Capacity of Cities in Southwest China Against the Background of Rapid Urbanization: A Case Study of Mianyang, Sichuan, China
19
作者 ZHANG Yu HOU Langong 《Journal of Landscape Research》 2019年第5期41-46,共6页
As Mianyang has neglected the coordination relationship with the ecological environment in the course of rapid urbanization,its ecological environment is getting worse.To this end,this study used the ecological footpr... As Mianyang has neglected the coordination relationship with the ecological environment in the course of rapid urbanization,its ecological environment is getting worse.To this end,this study used the ecological footprint method to explore the ecological carrying capacity of Mianyang from 2007 to 2014 under the background of rapid urbanization,which has important guiding significance for the future development of Mianyang.The results showed that in 2007–2014,the ecological footprint of Mianyang was greater than its ecological carrying capacity,indicating that Mianyang is in an ecological deficit.Specifically,the per capita ecological footprint showed a downtrend,and the per capita ecological carrying capacity showed a trend of smooth decline.In addition,the per capita ecological deficit was generally decreasing.In summary,Mianyang was generally in an ecological deficit in 2007–2014.Thus,the ecological environment of the region should be protected,in order to promote the sustainable development of the ecosystem in the region. 展开更多
关键词 ecological FOOTPRINT ecological carrying capacity ecological deficit/surplus Sustainable development Mianyang
下载PDF
Determination of the load bearing capacity of pre-stressed expandable props for ground support in underground mines 被引量:1
20
作者 Kunmeng Li Kaiyuan Jiang +3 位作者 Yuanhui Li Xin Wang Kai Liu Shuai Xu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第8期977-990,共14页
This paper aims to determine the load bearing capacity of pre-stressed expandable props with different geometries and load eccentricities for flexible support in underground mining or excavation.It is deduced that the... This paper aims to determine the load bearing capacity of pre-stressed expandable props with different geometries and load eccentricities for flexible support in underground mining or excavation.It is deduced that the expandable device could have much higher strength(>89 MPa)by laboratory tests,and the load bearing capacity of the expandable prop may depend on the stability of the supporting steel pipe structure.A good agreement was found between the laboratory test and numerical results in terms of the load bearing capacity and the final macro-bending failure pattern for expandable props with heights of 1.5 and 2.7 m,and the theoretical calculation for the strength of traditional steel structures is not directly suitable for the expandable props.Moreover,additional numerical simulations were performed for the expandable props with different normalized slenderness ratiosλ_(n)and loading eccentric distances e.The variation of stability coefficient of the expandable prop is in line with the Perry-Robertson equation and its correlation coefficients are fitted as a of 0.979 and b of 0.314.For estimating the load bearing capacity of the expandable props,the strength equation for traditional steel structures is improved by introducing a bending magnification factor and by modifying the normalized slenderness ratio to a converted slenderness ratio.Based on the underground field monitoring for the strength of expandable props with different heights,the empirical eccentric distances were back calculated,and a safety factor is introduced to obtain the designed strength of the expandable prop.In addition,a four-step design procedure is proposed for the expandable prop. 展开更多
关键词 Pillar stability Load bearing capacity Expandable prop Slenderness ratio Eccentric distance
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部