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保护非遗,需再造其当下生存自环境
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作者 袁曼琳 《中国民族博览》 2017年第1期60-61,共2页
非物质文化遗产发生在以往传统文化事项所处的自给自足的生态文化圈改变、大量异文化与本土文化开展对话之时。在全球一体化的时代背景下,这种对话不可避免。非物质文化遗产“活态流变性”的根本特征也表明,非物质文化遗产不可能是固定... 非物质文化遗产发生在以往传统文化事项所处的自给自足的生态文化圈改变、大量异文化与本土文化开展对话之时。在全球一体化的时代背景下,这种对话不可避免。非物质文化遗产“活态流变性”的根本特征也表明,非物质文化遗产不可能是固定不变的文化事项。立足于既定现实、在尽量减少其精神文化内涵消失的前提下,为非物质文化遗产营造一个当下生存的自环境,才是保护与传承非遗的理想状态。 展开更多
关键词 文化土壤 传播 时代语境 自环境
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Characteristics and fate behavior of environmentally persistent free radicals in atmospheric particulate matter
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作者 WANG Xueying CUI Long +2 位作者 XUE Yonggang HO Kinfai HUANG Yu 《地球环境学报》 CSCD 2024年第4期596-611,共16页
Background,aim,and scope Environmentally persistent free radicals(EPFRs)have received significant attention due to their longer lifetime and stable existence in various environments.The strong environmental migration ... Background,aim,and scope Environmentally persistent free radicals(EPFRs)have received significant attention due to their longer lifetime and stable existence in various environments.The strong environmental migration ability of particulate matter allows EPFRs to migrate over long-distance transport,thereby impacting the quality of the local atmospheric environment.Additionally,EPFRs can also adhere to atmospheric particles and interact with typical gaseous pollutants to affect atmospheric chemical reactions.EPFRs can produce some reactive organic species,promoting oxidative stress in the human body,damaging biological macromolecules and ultimately affecting the organism health.EPFRs are considered as a novel type of pollutant that affects human health.Despite their significance,there are few literatures available on the characteristics and fate behaviors of EPFRs up to date.Therefore,supplemental reviews are crucial for providing comprehensive understanding of EPFRs.Materials and methods This review summarizes the characteristics of EPFRs in particulate matter,outlines the generation mechanism and influencing factors of EPFRs,and the impacts of EPFRs on environmental quality and organism health.Results The content of EPFRs in particulate matter ranges from 1017 to 1020 spins∙g−1.Due to the strong mobility of atmospheric particulate matter,the long-term exposure to high levels of EPFRs may aggravate the impact of particulate matter on human health.The interaction between EPFRs and typical gaseous pollutants can alter their fate and influence atmospheric chemical reactions.EPFRs are mainly produced by transition metal elements and substituted aromatic hydrocarbons through electron transfer.Additionally,the chemical bond rupture of organic substances through heat treatment or ultraviolet radiation can also produce EPFRs,and heterogeneous reactions are capable producing them as well.The production of EPFRs is not only influenced by transition metal elements and precursors,but also by various environmental factors such as oxygen,temperature,light radiation,and relative humidity.Discussion EPFRs in atmospheric particulates matters are usually rich in fine particulates with obvious seasonal and regional variations.They can easily enter the human respiratory tract and lungs with inhalable particulates,thereby increasing the risk of exposure.Additionally,EPFRs in atmospheric particulates can interact with some typical gaseous pollutants,impacting the life and fate of EPFRs in the atmosphere,and alter atmospheric chemical reactions.Traditionally,EPFRs are generated by transition metal elements and substituted aromatic hydrocarbons undergoing electron transfer in the post-flame and cool-zone regions of combustion systems and other thermal processes to remove HCl,H_(2)O or CO groups,ultimately produce semiquinones,phenoxyls,and cyclopentadienyls.Recent studies have indicated that EPFRs can also be generated under the conditions of without transition metal elemental.Organics can also produce EPFRs through chemical bond rupture during heat treatment or light radiation conditions,as well as through some heterogeneous reactions and photochemical secondary generation of EPFRs.The presence or absence of oxygen has different effects on the type and yield of EPFRs.The concentration,type,and crystal type of transition metal elements will affect the type,content,and atmospheric lifetime of EPFRs.It is generally believed that the impact of transition metal element types on EPFRs is related to the oxidation-reduction potential.The combustion temperature or heat treatment process significantly affects the type and amount of EPFRs.Factors such as precursor loading content,pH conditions,light radiation and relative humidity also influence the generation of EPFRs.EPFRs can interact with pollutants in the environment during their migration and transformation process in environmental medium.This process accelerates the degradation of pollutants and plays a crucial role in the migration and transformation of organic pollutants in environmental media.The reaction process of EPFRs may lead to the production of reactive oxygen species(ROS)such as∙OH,which can induce oxidative stress,inflammation and immune response to biological lung cells and tissues,leading to chronic respiratory and cardiopulmonary dysfunction,cardiovascular damage and neurotoxic effects,ultimately impacting the health of organisms.Conclusions The interaction mechanism between EPFRs in particulate matter and gaseous pollutants remains unclear.Furthermore,research on the generation mechanism of EPFRs without the participation of transition metals is not comprehensive,and the detection of EPFRs is limited to simple qualitative categories and lack accurate qualitative analysis.Recommendations and perspectives Further research should be conducted on the generation mechanism,measurement techniques,migration pathways,and transformation process of EPFRs.It is also important to explore the interaction between EPFRs in atmospheric particulate matter and typical gaseous pollutants. 展开更多
关键词 particulate matter(PM) environmentally persistent free radicals(EPFRs) formation mechanism influencing factors
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南京市玄武区社区进修学院“五自实践”的探索
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作者 王信芳 业冰 杨长虹 《南京广播电视大学学报》 2016年第4期6-9,共4页
基于南京市玄武区生态式社区教育,玄武区社区进修学院从区域发展建构自环境、融合发展建立自组织、内涵发展开发自课程、创新发展打造自媒体、高位发展培育自特色等五个方面,形成推进社区教育发展的有效机制。
关键词 自环境 自组织 自课程 自媒体 自特色
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Habitat selection of Guizhou golden monkey (Phinopithecus rox-ellanae brelichi) in Fanjing Mountain Biosphere Reserve, China 被引量:3
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作者 吴钢 王宏昌 +2 位作者 付海威 赵景柱 杨业勤 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第3期197-202,共6页
Guizhou golden monkey (Phinopithecus roxellanae brelichi) is a peculiar, rare and endangered species. It is dis-tributed most narrowly and requires a rigorous habitat. In this study the habitats of Guizhou Golden Monk... Guizhou golden monkey (Phinopithecus roxellanae brelichi) is a peculiar, rare and endangered species. It is dis-tributed most narrowly and requires a rigorous habitat. In this study the habitats of Guizhou Golden Monkey were divided into three habitats: most suitable habitats, suitable habitats and marginally suitable habitats. The characteristics of the vegetation community, environmental factors and extreme environmental factors in the three habitats were systematically analyzed. The seasonal activity rule, activity area and the food characteristic of Guizhou golden monkey were also study at the same time. The results indicate that the evergreen and deciduous broadleaf mixed forest is the optimal living vegetation community for Guizhou golden Monkey, and the suitable annual temperature is 8-15 C, the extremely lowest temperature is 2.5 C, the extremely highest temperature is 25 C, and the optimal living altitude is 1500-1700 m. In the same area, the higher the vegetation diversity, the more suitable it is for the life of Guizhou golden monkey. Temperature and food are the main habitat factors in determining the activity scope of the guizhou golden monkey community. The Altitude, temperature and the characteristics of the vegetation community are the main limiting factors for habitat selection. 展开更多
关键词 HABITAT Phinopithecus roxellanae brelichi COMMUNITY Environmental factor Fanjing Mountain Biosphere Reserve
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Natural Resources Balance Sheet:Chinese Characteristics and International Practices 被引量:11
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作者 史丹 《China Economist》 2015年第4期22-43,共22页
This paper examines the explorations and practices of environmental- economic accounting in the international community, provides a comprehensive overview and evaluation of the nature and research progress of China's... This paper examines the explorations and practices of environmental- economic accounting in the international community, provides a comprehensive overview and evaluation of the nature and research progress of China's natural resources balance sheet, reviews the relevant systems of China's natural resources balance sheet and the development of ecological civilization, identifies the issues in the formulation of natural resources balance sheet and makes suggestions for improvement. 展开更多
关键词 natural resources balance sheet environmental-economic accounting ecological civilization
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An Exploration of the Interactive Web-based College English Teaching Model 被引量:1
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作者 周迎 《Sino-US English Teaching》 2006年第4期47-51,共5页
In the light of the theory of constructivism, the interactive web-based college English teaching model is intended to facilitate "autonomy", "inquiry" and "cooperation" in learning English. This paper presents a... In the light of the theory of constructivism, the interactive web-based college English teaching model is intended to facilitate "autonomy", "inquiry" and "cooperation" in learning English. This paper presents a research in which the interactive web-based college English teaching model intends to reshape the teacher's and learner's roles in the classroom. Based on the research, an exploration is made --- within the framework of the interactive web-based model --- on the design of "teaching model" and "learning model", its application and related potential problems. 展开更多
关键词 interactive web-based college English teaching model CONSTRUCTIVISM AUTONOMY inquiry cooperation
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CATASTROPHIC ECO-ENVIRONMENTAL CHANGE IN THE SONGNEN PLAIN,NORTHEASTERN CHINA SINCE 1900S 被引量:6
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作者 WANGHai-xia WANZhong-juan +2 位作者 YUShao-peng LUOXin-zheng SUNGuang-you 《Chinese Geographical Science》 SCIE CSCD 2004年第2期179-185,共7页
Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rat... Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thom Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions. 展开更多
关键词 ECO-ENVIRONMENT CATASTROPHE modeling Songnen Plain
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Assessing the Economic Value of Vernacular Architecture of Mountain Regions Using Contingent Valuation 被引量:6
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作者 Stella GIANNAKOPOULOU Dimitris DAMIGOS Dimitris KALIAMPAKOS 《Journal of Mountain Science》 SCIE CSCD 2011年第5期629-640,共12页
Human pressure on mountain resources poses certain threats to their natural and man-made environment. Although there are many parameters involved, one of the driving forces behind this situation is the emphasis given ... Human pressure on mountain resources poses certain threats to their natural and man-made environment. Although there are many parameters involved, one of the driving forces behind this situation is the emphasis given so far only to the market value of mountain goods and services, ignoring the true social and environmental costs of using mountain resources. Towards this direction, the use of non-market valuation techniques could prove to be beneficial. Bearing in mind the above remarks, the paper presents an application of the Contingent Valuation Method, which aims at estimating the monetary value of a mountain settlement’s vernacular architecture, namely Metsovo. For this purpose, the survey focuses on Metsovo visitors’ willingness to pay a single annual voluntary contribution to an institution that would be founded in order to undertake all necessary actions required to preserve the town’s traditional character. The results are very promising and indicate that vernacular architecture holds a significant economic value that could justify the implementation of appropriate policies towards the protection of vernacular settlements in mountain areas. 展开更多
关键词 Non-market valuation Vernacular architecture Contingent valuation
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Taxonomic Distinctness of Macrofauna as an Ecological Indicator in Laizhou Bay and Adjacent Waters 被引量:9
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作者 ZHOU Hong HUA Er ZHANG Zhinan 《Journal of Ocean University of China》 SCIE CAS 2010年第4期350-358,共9页
In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tes... In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising. 展开更多
关键词 Taxonomic distinctness MACROFAUNA ecological indicator BIODIVERSITY Laizhou Bay Bohai Sea
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Solution of pavement temperature field in“Environment-Surface”system through Green's function 被引量:2
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作者 陈嘉祺 李亮 +2 位作者 赵炼恒 但汉成 姚辉 《Journal of Central South University》 SCIE EI CAS 2014年第5期2108-2116,共9页
In order to simplify the boundary conditions of pavement temperature field,the "Environment-Surface" system which considered the natural environment and pavement surface was established.Based on this system,... In order to simplify the boundary conditions of pavement temperature field,the "Environment-Surface" system which considered the natural environment and pavement surface was established.Based on this system,the partial differential equations of the one-dimensional heat conduction in the pavement were established on the basis of the heat transfer theory.Furthermore,the function forms of the initial and boundary conditions of the equations were created through the field experiments.The general solution of the pavement one-dimensional heat conduction partial differential equations was acquired by using Green's function,and the explicit expression of pavement temperature field under specific constraint conditions was derived.For the purpose of analysis,the pavement temperatures in different seasons were calculated using the explicit expression of pavement temperature field,and the calculation accuracy was analyzed through the comparison between measured and calculated values.Then,the relationship between fitting accuracy and calculation accuracy of pavement temperatures was analyzed.The analysis results show that: the usage of "Environment-Surface" system simplifies the calculation of pavement temperature field; the relative error between calculated and measured values is generally less than 7% and is seldom influenced by seasons; there is a positive correlation between the calculation accuracy and the fitting accuracy of pavement surface temperature; high fitting accuracy would result in less error of pavement temperature prediction. 展开更多
关键词 road engineering pavement temperature field "Environment-Surface" system heat transfer theory Green's function
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ANALYSIS OF CAPITAL FLOW WITH GIS——Two Approaches for Regional Investment in China 被引量:1
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作者 YAO Yong-ling ( Public Administration School, Renmin University of China, Beijing 100872, P. R. China) 《Chinese Geographical Science》 SCIE CSCD 2003年第1期2-8,共7页
GIS technology has been mostly concerned with handling physical data andmodeling physical environment. However, the retirements of GIS for handling socio-economicinformation in many cases are different from those conc... GIS technology has been mostly concerned with handling physical data andmodeling physical environment. However, the retirements of GIS for handling socio-economicinformation in many cases are different from those concerning phenomena in the physical environment.Analysis of capital flow among regions requires the transitions both from economic values tophysical landscape and from physical surface to economic explanation. Rapid growth of Chineseeconomy comes mainly from investment. There are two main ways for obtaining high growth ofinvestment. One is government expenditure which usually invests in regional facility and amenityblock, which is regarded as stimulus for attracting investment. The other is the creation ofinvesting center and corresponding capital source areas, both of which need the central city withthe highest growth rate of investment among regions. This paper presents the cluster areas of bothgovernment revenue and total investment, the potential situation of capital flow between centralcity Shanghai and its neighbor provinces by using Classification' and Interpolation' functions ofArcView GIS. 展开更多
关键词 capital flow geographic information system (GIS) regional investment cluster analysis
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Influence of Tourists′ Environmental Tropisms on Their Attitudes to Tourism and Nature Conservation in Natural Tourist Destinations: A Case Study of Jiuzhaigou National Park in China 被引量:5
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作者 CHENG Shaowen ZHANG Jie +2 位作者 LU Shaojing XU Feifei ZHANG Honglei 《Chinese Geographical Science》 SCIE CSCD 2011年第3期377-384,共8页
People′s environmental tropism has an effect on their understanding of tourism-nature relationship,and also influences their attitudes to natural resources utilization and environmental protection.Taking Jiuzhaigou N... People′s environmental tropism has an effect on their understanding of tourism-nature relationship,and also influences their attitudes to natural resources utilization and environmental protection.Taking Jiuzhaigou National Park of China as a study case,the authors conducted some quantitative analyses with the tools of SPSS 16.0 and LISREL 8.7,to explore the influence of tourists′ environmental tropism on their attitudes to tourism and nature conservation in the natural tourist destination.Three hypotheses and the theoretic model of influences of tourists′ environmental tropism on their attitudes to tourism and nature conservation have been tested and accepted based on the Structural Equation Model analysis on survey data collected in Jiuzhaigou National Park of China.Some conclusions were drawn as follows: 1) tourists′ human-prioritized concept influences their cognition to tourism-nature relationship.This concept has a positive influence on their supportive attitudes to tourism,but a negative influence on their attitudes to nature conservation;2) tourists′ human-nature coordination concept has a positive influence on their supportive attitudes to both tourism and nature conservation,especially to the latter.This paper generally proves that human′s environmental tropism does have an influence on their attitudes to tourism and nature conservation in natural tourist destinations. 展开更多
关键词 environmental tropism nature conservation natural tourist destination tourism-nature relationship Jiuz- haigou National Park
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Distribution of Polychaete Assemblage in Relation to Natural Environmental Variation and Anthropogenic Stress 被引量:1
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作者 ZAN Xiaoxiao ZHANG Chongliang +2 位作者 XU Binduo XUE Ying REN Yiping 《Journal of Ocean University of China》 SCIE CAS 2015年第4期749-758,共10页
Polychaete are diverse species of the soft-bottom community, and are often used as indicators in environment monitoring programs. However, the effects of anthropogenic activities and natural environmental variation on... Polychaete are diverse species of the soft-bottom community, and are often used as indicators in environment monitoring programs. However, the effects of anthropogenic activities and natural environmental variation on polychaete assemblage are rarely addressed. The goals of this study are to identify the effects of natural environmental variation and anthropogenic stress on poly- chaete assemblage, and to explore the relationship between the polychaete assemblage structure and anthropogenic stress without considering the natural environmental variation. Based on the data collected from the surveys conducted in the tidal fiat of Jiaozhou Bay, the relationship between polychaete assemblage structure and environmental variables was determined using multivariate statis- tical methods including hierarchical cluster analysis, multidimensional scaling (MDS) and canonical correspondence analysis (CCA). The results showed that the polychaete assemblage was dominated by two species, Amphictenejaponica and Heteromastusfiliformis, and could be divided into two subgroups characterized by high and low species abundance. CCA illustrated that the natural environ- mental variables including water temperature and the distance from coast had primary effects on the polychaete assemblage structure; while stress of contaminants, such as As and Hg, had the secondary influences; and stress from the aquacultured species, mainly Ruditapes philippinarum, had a limited effect. Colinearity between the natural environmental variables and anthropogenic stress variables caused a critical divergence in the interpretation of CCA results, which highlighted the risk of a lack of information in en- vironment assessment. Glycinde gurjanovae, Sternaspis scutata and Eulalia bilineata may serve as the 'contamination indicators', which need to be confirmed in future studies. 展开更多
关键词 POLYCHAETE tidal flat anthropogenic stress CONTAMINANT AQUACULTURE multivariate analysis canonical correspondenceanalysis (CCA)
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Impending Pollution of Betare Oya Opencast Mining Environment (Eastern Cameroon) 被引量:2
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作者 Tehna Natanael Nguene Feudoung Daniel +4 位作者 Etame Jacques Medza Ekodo Jean Marc Noa Tang Sylvie Sub Emmanuel Cheo Bilong Paul 《Journal of Environmental Science and Engineering(B)》 2015年第1期37-46,共10页
Mining resources are offered by the natural milieu and liable to exploitation. Raw materials extracted are essential for jewellery and economy. But in most cases, the environmental impact assessment is disappointing. ... Mining resources are offered by the natural milieu and liable to exploitation. Raw materials extracted are essential for jewellery and economy. But in most cases, the environmental impact assessment is disappointing. In this study conducted at Betare Oya, mining residues are directly disposed in the immediate environment without passing through the tailing ponds for treatment, despite environmental laws and standards. Soluble components of matter are slowly dissolved, drained by meteoric water and flowed into tail bay vicinity. Soil and mining residues were sampled in Mari, Mbigala, Mboufa and Bedobo, respectively, four sub-watershed of Lom, the main river of the region. Concentration of nine MTE (metallic trace elements): As, Cd, Cr, Cu, Co, Ni, Pb, Zn and Hg were determined by ICP-MS (inductively coupled plasma-mass spectrometry). Highest concentrations of trace and toxic metals in soil and mining residues are: Cr (210 mg·kg-1) 〉 Zn (136 mg·kg-1) 〉 Ni (64 mg·kg-1) 〉 As (34 mg·kg-1) 〉 Cu (30 mg·kg-1) 〉 Pb (25 mg·kg-1) 〉 Co (17 mg·kg-1) 〉 Cd (0.5 mg·kg-1) 〉 Hg (0.1 mg·kg-l), respectively. These results let assume that it is a risk of environmental pollution and poisoning relative to these elements around Betare Oya opencast mining area, with impact on human health. 展开更多
关键词 MINING mounds mining residues POLLUTION metallic trace elements toxicology.
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Dynamic behavior of reinforced concrete frame structure during construction 被引量:3
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作者 田明革 易伟建 《Journal of Central South University of Technology》 EI 2008年第3期418-422,共5页
The effects of concrete's time-variant elastic modulus,casting structural components,assembling temporary shoring framework system,and shock by operating construction equipment on dynamic behavior of the reinforce... The effects of concrete's time-variant elastic modulus,casting structural components,assembling temporary shoring framework system,and shock by operating construction equipment on dynamic behavior of the reinforced concrete frame structure during construction were investigated. The dynamic tests of an eight-storey reinforced concrete frame structure during full-scaled stages of the sixth storey construction cycle were carried out by ambient vibration. Natural frequencies,corresponding mode shapes and damping ratio were determined by power spectrum processing the tested signal data in frequency domain. The changes of frequencies,mode shapes and damping ratios at different construction stages were given. The results show that natural frequencies and modal damping ratios reach the maximum at stage of casting fresh concrete,especially for higher modes. Modal damping ratios at each construction stage are less than 5% of those during usage. 展开更多
关键词 structural dynamics ambient vibration structure during construction mode shape natural frequency modal damping ratio
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Sustainable Development and the Basic Value of Natural Environment 被引量:1
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作者 Jia Zhong Li Jianhua 《Chinese Journal of Population,Resources and Environment》 2009年第1期89-93,共5页
Contrast with artificial environment, the multi-level self-organizational system of nature has great gain. Sustain-able material environment should respect nature: non-rubbish and super-cycle quality of natural ecosys... Contrast with artificial environment, the multi-level self-organizational system of nature has great gain. Sustain-able material environment should respect nature: non-rubbish and super-cycle quality of natural ecosystem offers the material source of human development, fractal structure of nature offers new field of space and information source to this high-density and information-based society, dissipative structure of nature links the new system of energy with whole ecosystem organi-cally, and life-chain regulation is the base of sustainable life environment. Nature guarantees the physical healthy environ-ment by its all-dimension healthy factor, constructs the mental healthy environment by its quality of co-ordinate and chaos, so that guarantees the whole emergence of sustainable develop-ment on the 'super-science' level. In the view of sustainable development, construction, green economy and human health are basic fields. With the concept of ecosystem regulation, we can relate these fields organically and fulfill the task of human health, welfare and sustainable development. Ecosystem regulation is the base of sustainable development's new para-digm. 展开更多
关键词 sustainable development natural environment ECOSYSTEM HEALTH SELF-ORGANIZATION
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Effect of Cropland Occupation and Supplement on Light-temperature Potential Productivity in China from 2000 to 2008 被引量:7
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作者 YANG Xiaohuan CHENG Chuanzhou LI Yuejiao 《Chinese Geographical Science》 SCIE CSCD 2010年第6期536-544,共9页
There are more people but less land in China,so food safety has always been a most important issue government concerned.With continuous population increase,economic development and environment protection,cropland occu... There are more people but less land in China,so food safety has always been a most important issue government concerned.With continuous population increase,economic development and environment protection,cropland occupation and supplement are unavoidable.It not only leads to the variation of cropland area,but also makes the light-temperature potential productivity per unit area different due to regional climate differentiation,therefore impacts the total potential productivity and food output eventually.So,it is necessary to analyze the climate differentiation between occupation and supplement cropland areas and to study its impact on total potential productivity,which is significant to reasonably develop natural resources and instruct agricultural arrangement.This study firstly discussed the variation and distribution of occupation and supplement croplands in China from 2000 to 2008,then analyzed the climate differentiation between occupation and supplement cropland areas and its effect on light-temperature potential productivity.The results demonstrate:1) From 2000 to 2008,the cropland variation presented occupation in the south and supplement in the north,but overall decreased.Supplement cropland was mainly from ecological reclamation(77.78%) and was mainly distributed in Northeast China and Northwest China with poor climatic and natural conditions.Occupation cropland was mainly used for construction(52.88%) and ecological restoration(44.78%) purposes,and was mainly distributed in the Huang-Huai-Hai Plain,and the middle and lower reaches of the Changjiang(Yangtze) River with better climatic and natural conditions.2) The climate conditions were quite different in supplement and occupation cropland areas.The annual precipitation,annual accumulated temperature and average annual temperature were lower in the supplement cropland area,and its average po-tential productivity per unit was only 62% of occupation cropland area,which was the main reason for the decrease of total potential productivity.3) Cropland occupation and supplement led to the variation of total potential productivity and its spatial distribution.The productivity decreased in the south and increased in the north,but had a net loss of 4.38315×107 t in the whole country.The increase of cropland area was at the cost of reclaiming natural forest and grassland resources,and destroying natural ecological environment,while the decrease of cropland area was mainly due to a lot of cropland occupied by urban-rural construction,which threatened the sustainable use of cropland resources. 展开更多
关键词 CROPLAND cropland occupation cropland supplement climate condition light-temperature potential productivity China
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Study of CNG/diesel dual fuel engine's emissions by means of RBF neural network 被引量:5
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作者 刘震涛 费少梅 《Journal of Zhejiang University Science》 CSCD 2004年第8期960-965,共6页
Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CN... Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resumé, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data. 展开更多
关键词 Dual fuel engine Emission performance RBF neural network
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Artificial substrates preference for proliferation and immigration in Aurelia aurita(s. l.) polyps 被引量:1
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作者 FENG Song LIN Jianing +1 位作者 SUN Song ZHANG Fang 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第1期153-162,共10页
The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the pro... The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the proliferation of the benthic stage(polyps). Previous experiments have mainly focused on the substrate choices of Aurelia spp. planulae. However, substrate preferences for the proliferation and immigration of polyps have not been reported. We monitored the propagation and immigration of Aurelia aurita(s. l.) polyps on two natural and nine artificial substrates at constant temperature(20±0.5°C) and salinity(30±0.5) in beakers and a glass aquarium in the laboratory, respectively. The results showed that, among artificial substrates, the highest number for polyp proliferation and immigration was found on nets, rigid polyvinyl chloride plates(RPVC), and wood. The lowest density of polyps was present on iron plates. Among natural substrates, the asexual reproduction rate of polyps on Patinopecten yessoensis(Jay, 1857) shells was significantly higher than Azumapecten farreri(Jones & Preston, 1904). On the account of the distinction in the roughness, chemical properties and biofilms of these material surfaces, bare artificial or natural substrates discriminatively affect the proliferation and the immigration of Aurelia spp. polyps at laboratory. These observations suggest that, even in the natural environment, different materials and texture may influence the composition and the abundance of the fouling communities and the assemblages of polyps and, indirectly, have effects on the amounts of released medusae. 展开更多
关键词 artificial substrates Aurelia aurita(s.l.) polyps proliferation immigration
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Avian magnetic compass:Its functional properties and physical basis 被引量:2
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作者 Roswitha WILTSCHKO Wolfgang WILTSCHKO 《Current Zoology》 SCIE CAS CSCD 北大核心 2010年第3期265-276,共12页
The avian magnetic compass was analyzed in bird species of three different orders - Passeriforms, Columbiforms and Galliforms - and in three different behavioral contexts, namely migratory orientation, homing and dire... The avian magnetic compass was analyzed in bird species of three different orders - Passeriforms, Columbiforms and Galliforms - and in three different behavioral contexts, namely migratory orientation, homing and directional conditioning. The respective findings indicate similar functional properties: it is an inclination compass that works only within a functional window around the ambient magnetic field intensity; it tends to be lateralized in favor of the fight eye, and it is wavelength-dependent, requiring light from the short-wavelength range of the spectrum. The underlying physical mechanisms have been identified as radical pair processes, spin-chemical reactions in specialized photopigments. The iron-based receptors in the upper beak do not seem to be involved. The existence of the same type of magnetic compass in only very distantly related bird species suggests that it may have been present already in the common ancestors of all modem birds, where it evolved as an all-purpose compass mechanism for orientation within the home range [Current Zoology 56 (3): 265-276, 2010]. 展开更多
关键词 Magnetic compass MIGRATION HOMING Directional training Inclination compass Radical pair processes
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