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基于生态镶嵌模式的生态修复技术初探 被引量:1
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作者 周斌 盛维华 黄俏蕾 《包装世界》 2015年第4期64-66,共3页
生态威胁是全球三大威胁之一,而生态修复是解决该问题的有效手段。本研究项目在现有研究成果的基础上,结合"景观镶嵌结构"、"植物镶嵌体系"等相关理论,将空间的异质性镶嵌引入生态层面,提出"生态镶嵌"这... 生态威胁是全球三大威胁之一,而生态修复是解决该问题的有效手段。本研究项目在现有研究成果的基础上,结合"景观镶嵌结构"、"植物镶嵌体系"等相关理论,将空间的异质性镶嵌引入生态层面,提出"生态镶嵌"这一生态修复的新模式。通过空间格局镶嵌、生物多样性镶嵌等方法,从宏观和微观两方面进行生态修复,并在此基础上提出"生态绿脉"理想模型,且以宁波等城市为例对"生态绿脉"理想模型进行实证研究,研究表明该模式在实现自然生态、人文生态、经济生态相互耦合上具有实际应用价值。 展开更多
关键词 生态修复 生态镶嵌 生态绿”模型
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水利风景区旅游规划研究——以湖南攸县酒仙湖景区概念性规划为例 被引量:2
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作者 张宝铮 《中外建筑》 2010年第6期77-79,共3页
本文从酒仙湖景区的旅游资源分布和特点,以及旅游市场分析和发展策略等方面分析,对酒仙湖景区景点共性加以提炼,总结出生态脉、水韵脉、文化脉三条主线,以三条文脉综合构筑成酒仙湖独具的特色,象征着中国传统"天人合一"的思想。
关键词 旅游 生态脉 水韵 文化 休闲
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滨水绿地步行空间人性化设计研究——以宁波市“三江六岸”滨江休闲带为例 被引量:4
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作者 林俏 《现代园艺》 2016年第13期122-123,共2页
高品质的城市环境得益于良好的公共空间,而人性化的步行空间构建能强化公共空间导向性的有效途径。研究从空间的人性化出发,探究其在生态绿脉和标识系统构建上的特色设计,以宁波市"三江六岸"滨江休闲带为例,分析城市中心区的... 高品质的城市环境得益于良好的公共空间,而人性化的步行空间构建能强化公共空间导向性的有效途径。研究从空间的人性化出发,探究其在生态绿脉和标识系统构建上的特色设计,以宁波市"三江六岸"滨江休闲带为例,分析城市中心区的步行空间环境,以提升步行空间的活力。 展开更多
关键词 步行空间 生态绿 标识系统 三江六岸
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Utilisation and Management Changes in South Kyrgyzstan's Mountain Forests 被引量:3
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作者 Matthias Schmidt 《Journal of Mountain Science》 SCIE CSCD 2005年第2期91-104,共14页
Using political ecology as its conceptual framework,this paper focuses on the changes in forest utilisation and management of South Kyrgyzstan’s walnut-fruit forests over the last century. The aim of this study on hu... Using political ecology as its conceptual framework,this paper focuses on the changes in forest utilisation and management of South Kyrgyzstan’s walnut-fruit forests over the last century. The aim of this study on human-environment interactions is to investigate the relationship between actors on the one side,their interests and demands,and the forests and forested lands on the other. Forest resource utilisation and management — and even the recognition of different forest products as resources — are connected with political and socio-economic conditions that change with time. The walnut-fruit forests of South Kyrgyzstan are unique,characterised by high biodiversity and a multiplicity of usable products;and they have been utilised for a long time. Centralised and formal management of the forests started with the Russian occupation and was strengthened under Soviet rule,when the region became a part of the USSR. During this era,a state forest administration that was structured from Moscow all the way down to the local level drew up detailed plans and developed procedures for utilising the different forest products. Since the collapse of the Soviet Union,the socio-political and economic frame conditions have changed significantly,which has brought not only the sweeping changes in the managing institutions,but also the access rights and interests in the forest resources. At present,the region is suffering from a high unemployment rate,which has resulted in the forests’ gaining considerable importance in the livelihood strategies of the local population. Political and economic liberalization,increased communication and trans-regional exchange relations have opened the door for international companies and agents interested in the valuable forest products. Today,walnut wood and burls,walnuts,wild apples and mushrooms are all exported to various countries in the world. Scientists and members of various international organisations stress the ecological value of the forests and are trying to establish nature conservation areas. Nevertheless,it is to fear that a multiplicity of interrelated factors — the present transformation and globalization processes,the appearance of new actors,the local population’s insecure economic situation and the erosion of managing institutions — are all leading to an intensified and unregulated exploitation of the forests,resulting in their degradation. 展开更多
关键词 KYRGYZSTAN Tian Shan walnut-fruit forest political ecology resource management forest utilisation
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Diversity patterns and phylogenetic structure of vascular plants along elevational gradients in a mountain ecosystem, South Korea 被引量:7
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作者 CHUN Jung-Hwa LEE Chang-Bae 《Journal of Mountain Science》 SCIE CSCD 2018年第2期280-295,共16页
Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study,... Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type. 展开更多
关键词 Community structure Deterministicprocess Elevational gradient Neutral process Phylogenetic diversity Species richness
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Evaluation of Nitrogen Cycling Associated with Agricultural Production and Environmental Load in a Mountain Region,in Hokkaido,Japan
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作者 LIANG Lei JIN Datian HU Ning 《Journal of Mountain Science》 SCIE CSCD 2008年第2期130-139,共10页
This study examined the nitrogen cycling associated with agricultural production and environmental load in central Hokkaido. The nitrogen (N) budget analysis model offers a new set of tools for evaluating N cycling in... This study examined the nitrogen cycling associated with agricultural production and environmental load in central Hokkaido. The nitrogen (N) budget analysis model offers a new set of tools for evaluating N cycling in agro-ecosystems. The cycling index (CI) is a useful tool for estimating optimal N flows in farmlands. The fertilization index (FI) is a useful indicator for characterizing the N flows related to farms. Using these parameters, we analyzed all farm systems to estimate the optimal N cycling for minimizing N pollution in groundwater and maximizing agricultural production in mountain regions of Japan. The results showed that the critical N application rate (chemical fertilizer + manure) was 143.3 kg N ha-1 y-1. The critical inter-system input (chemical fertilizer N, imported food and feed N, and natural supplied N) was 169.2 kg N ha-1 y-1. 展开更多
关键词 Cycling index mountain agro-ecosystem N cycling N load N management HOKKAIDO JAPAN
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Riparian Vegetation Dynamics Across Two Different Landscapes Along the River Cauvery in the Kodagu Region of Western Ghats
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作者 C.SUNIL R.K.SOMASHEKAR B.C.NAGARAJA 《Journal of Mountain Science》 SCIE CSCD 2012年第3期351-361,共11页
Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the ups... Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the upstream sections of the River Cauvery are still intact, as they are located in sacred groves. To understand the dynamism of riparian forests exposed to anthropogenic pressures, the upstream stretch of Cauvery extending from Kushalanagara to Talacauvery (~102 km) was categorized into two landscapes: agro ecosystem and sacred (i.e. preserved). The tree species were sampled using belt transects at 5 km intervals and the regeneration status of endemic species assessed using quadrats. A total of 128 species belonging to 47 families, and representing 1,590 individuals, was observed. Amongst them, 65% of unique species were exclusive to sacred landscapes. A rarefaction plot confirmed higher species richness for the sacred compared to the agro ecosystem landscapes, and diversity indices with more evenness in distribution were evident in sacred landscapes. A significant loss of endemic tree species in the agro ecosystem landscapes was found. Overall, this study demonstrates that an intense biotic pressure in terms of plantations and other anthropogenic activities have altered the species composition of the riparian zone in non-sacred areas. A permanent policy implication is required for the conservation of riparian buffers to avoid further ecosystem degradation and loss of biodiversity. 展开更多
关键词 Western Ghats Riparian vegetation Cauvery River Sacred grove Agro ecosystemlandscape Diversity indices Endemic species.
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Foraging ecology of the globally threatened Nilgiri Wood Pigeon(Columba elphinstonii)in the Western Ghats,India
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作者 Sellamuthu SOMASUNDARAM Lalitha VIJAYAN 《Chinese Birds》 2010年第1期9-21,共13页
Foraging ecology of the globally endangered Nilgiri Wood Pigeon(Columba elphinstonii) was investigated in the Western Ghats,India,using faecal sampling and direct observations.The birds fed on fruits of 39 plant speci... Foraging ecology of the globally endangered Nilgiri Wood Pigeon(Columba elphinstonii) was investigated in the Western Ghats,India,using faecal sampling and direct observations.The birds fed on fruits of 39 plant species,on seeds of 11 species,flowers and leaf buds of four species and a few ground invertebrates.Direct observations across seasons showed nine plant species were selected more often(47% of observations),with fruits of the members of the family Lauraceae the most preferred.Gleaning accounted for 76% of feeding methods throughout the year.Feeding was mainly from twigs at the edges on the upper and middle canopy(> 6 m).Frequency of feeding on fruits correlated significantly with fruit abundance,which depended on rainfall.The present study indicates that the pigeon requires a wide variety of diets from different forest environments.Conservation of this species depends on preserving all habitat types required to meet their resource needs throughout the year. 展开更多
关键词 Nilgiri Wood Pigeon Columba elphinstonii foraging ecology Western Ghats INDIA
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The Role of Chilean Mountain Areas in Time of Drought and Energy Crisis:New Pressures and Challenges for Vulnerable Ecosystems
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作者 Rafael SáNCHEZ Carla MARCHANT Axel BORSDORF 《Journal of Mountain Science》 SCIE CSCD 2012年第4期451-462,共12页
In the summer of 2010/2011 Chile suffered the third most severe energy and water supply crisis in only one decade. This may be surprising as the Andes which accompany the country along 4,200 km are a water tower and c... In the summer of 2010/2011 Chile suffered the third most severe energy and water supply crisis in only one decade. This may be surprising as the Andes which accompany the country along 4,200 km are a water tower and could provide more electricity and water than needed. On top of that, it has to be mentioned that Chile also counts with sunny and windy climates and with excellent geothermal energy resources and thus has a huge potential as far as renewable energies are concerned. After analyzing the existing natural conditions, the infrastructure and the present challenges of climate change, it has to be asked in which way Chile can make use of this potential in the near future, considering the legal and political situation and the technological opportunities. It seems that the resources are still hidden in the Andes, and only the key is missing to realize the country's natural potential. This research has been based on the analysis of existing literature, media, quantitative data from government institutions and other antecedents obtained by the authors in field work done in the South of Chile in 2OLO. The added value of this compilation lies in the comprehensive perspective, linking the knowledge of climatologists, hydrologists, mountain researchers and energy experts in order to support a sustainable energy and water supply for the future in Chile. From this present research, it can be concluded that Chile necessarilyhas to adopt new energy-related strategies, particularly those aimed at diminishing the strong dependence on traditional sources of energy and establishing new techniques and technologies for generating electrieity and utilizing the vast potential that the country is ready to offer, such as that provided by the Andes along 4,200 kilometers. 展开更多
关键词 Mountain region ANDES Energy supply Chile
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Epidemiology of pulmonary hypertension in the elderly
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作者 Cihan Orem 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2017年第1期11-16,共6页
1 Introduction Pulmonary hypertension (PH) is a haemodynamic and pathophysiological condition defined as increase in mean pulmonary arterial pressure≥ 25 mmHg at rest as assessed by right heart catheterization (... 1 Introduction Pulmonary hypertension (PH) is a haemodynamic and pathophysiological condition defined as increase in mean pulmonary arterial pressure≥ 25 mmHg at rest as assessed by right heart catheterization (RHC). 展开更多
关键词 EPIDEMIOLOGY Pulmonary hypertension The elderly
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Ecological Status and Uses of Juniper Species in the Cold Desert Environment of the Lahaul Valley, North-western Himalaya, India
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作者 Yashwant S.RAWAT Colin S.EVERSON 《Journal of Mountain Science》 SCIE CSCD 2012年第5期676-686,共11页
The juniper species Juniperus polycarpos C. Koch, J. indica Bertol. and J. communis L. var. saxatilis (Pallas) are important elements of the forest vegetation in Lahaul valley in the north-western Himalaya. Their ab... The juniper species Juniperus polycarpos C. Koch, J. indica Bertol. and J. communis L. var. saxatilis (Pallas) are important elements of the forest vegetation in Lahaul valley in the north-western Himalaya. Their ability to grow under the barren and xeric conditions of cold deserts makes them particularly suited for afforestation programmes under these eeologieal conditions. In the Lahaul valley, juniper species are used as subsistence resources and for religious purposes. Excessive removal of juniper wood and leaves by the local population, overgrazing, habitat fragmentation and low regeneration potential are the main obstacles to eonservation of juniper forests in this region. The present study was carried out to assess density, basal area and importance value index (WI) of the local vegetation as well as uses and amounts of juniper wood and leaves removed from the local forests. Pressure on relict juniper forests due to grazing animals and intensive removal of wood and leaves by the loeal population was found to be greater at an altitude above 3,00o m. The results of the study demonstrated that the different juniper speeies were adapted to specific altitude ranges. A higher species density was recorded at lower altitude except for J. indica which was only present at high altitude (〉3,200 m) on south-facing slopes. Density, basal area and IVI of J. polycarpos were higher at Hinsa (2,7oo m) than at Jahlma (3,000 m). The rapid loss of vegetation due to overuse and habitat degradation has made the eonservation of juniper forests an important priority in the Lahaul valley. J. polycarpos at loweraltitude and J. indica at higher altitude are ecologically the more suitable species for the successful implementation of conservation programmes. The support of rehabilitation programmes by regional authorities is essential for the reestablishment of the local juniper forests. 展开更多
关键词 JUNIPER Distribution Utilization Pattern AGROFORESTRY FOREST CONSERVATION
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Birds in rocky habitats of the Tatra Mountains (Carpathians): species diversity and multiple ecological relationships
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作者 Michal CIACH Filip KOWALSKI 《Journal of Mountain Science》 SCIE CSCD 2016年第6期1078-1084,共7页
Rocky habitats are regarded as biodiversity hot-spots. Along with high species diversity, diverse ecological relationships can be observed in these habitats. Large groups of bird species use rocks in various ways: as... Rocky habitats are regarded as biodiversity hot-spots. Along with high species diversity, diverse ecological relationships can be observed in these habitats. Large groups of bird species use rocks in various ways: as perching/roosting sites, breeding or foraging habitats, information exchange sites, display arenas or as sources of minerals and water. Because of the inaccessibility of these environments, their role and importance to animals has been underestimated. We evaluated the use of rocky habitats by birds in the Tatra Mountains (49°13′N; 19°57′E, Carpathians, central Europe). Rocky habitats were used by 29 bird species, eight of which used cliffs directly (i.e. for nesting, foraging or resting). The number of species recorded as using cliffs was correlated with the surface area of the cliff face. A total of 2o forms of rocky habitat use were recorded, in five behavioural categories: vocalization, foraging, perching, flight and nesting. Prevailing behaviours were flying by a rock face, circling above the face, and vocalization on a tree/shrub growing next to a rock. Rocks provide a nesting habitat for specialized petrophilic species and permit the existence of numerous ecological relations between species and habitats. The results of this study show that rocky habitats support the diversity of ecological relationships. 展开更多
关键词 Bird community Rock CLIFF Mountains Alpine species Ecological relationships
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Territorial Repartition and Ecological Importance of Wetlands in Moldova (Romania) 被引量:1
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作者 G. Romanescu C. Stoleriu C. Zaharia 《Journal of Environmental Science and Engineering》 2011年第11期1435-1444,共10页
The present paper is the first study conducted in Romania on the inventory of wetlands of a large surface of the country. The focus of this study is the Moldavian Plateau, located in the east of Romania. It is delimit... The present paper is the first study conducted in Romania on the inventory of wetlands of a large surface of the country. The focus of this study is the Moldavian Plateau, located in the east of Romania. It is delimitated by the Eastern Carpathians on the west, the Romanian Plain on the south, the Ukrainian border on the north and the Prut Valley (border with the Republic of Moldavia) on the east. Although the Moldavian Plateau is situated in the driest region of Romania, the majority of the wetlands and of the low discharge rivers is found in this region. The existence of numerous wetlands, respectively small ponds, is influenced by the human activities and the scarcity of water resources. The impermeable clayey substratum favored the occurrence and survival of a large number of wetlands. Most of them are found in the northern Moldavian Plain, and the fewest to the south, in the Covurlui Plateau. The most important wetlands are those developed along the two main rivers draining this territory: Prut and Siret. Unfortunately, Siret River floodplain has been in most of its part protected by means of flood prevention dikes. Consequently, many of the wetlands entered agricultural use. 展开更多
关键词 Aridization deep waters INVENTORY TYPOLOGY WETLANDS
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Spatiotemporal Dynamics of a Páramo Ecosystem in the Northern Ecuadorian Andes 1988-2007
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作者 Oliver WIGMORE Jay GAO 《Journal of Mountain Science》 SCIE CSCD 2014年第3期708-716,共9页
Paramo is a term used to describe tropical alpine vegetation between the continuous timberline and the snow line in tbe Northern Andes. Paramo environments provide important species habitat and ecosystem services. Cha... Paramo is a term used to describe tropical alpine vegetation between the continuous timberline and the snow line in tbe Northern Andes. Paramo environments provide important species habitat and ecosystem services. Changes in spatial extent of the paramo ecosystem at Pambamarca in the Central Cordillera of the northern Ecuadorian Andes were analysed using multi-temporal Landsat TM/ETM+ satellite data. The region suffered a loss of 1826.6 ha or 20% of the total area at a rate of 100 ha/annum during 1988-2007 period. It is found that permanent paramo cover decreased from 8350 ha in 1988 to 5864 ha in 2007 at a fairly constant rate (R^2=0.94). This loss is attributed to expansion of commercial agriculture and floriculture in the valleys coupled with increased population pressure. Land at higher elevations has been cleared for small scale agriculture. Loss of the paramo ecosystem will exert a number of negative impacts on ecosystem services and livelihoods of the local population at Pambamarca. 展开更多
关键词 Paramo ecosystem Change analysis Remote sensing ANDES
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Physical Land Suitability Assessment for the Large Cardamom Amomum subulatum Roxb.Cultivation in Hills of Kathmandu Valley
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作者 Nabarath Baniya Michael Behme Saroja Baniya 《Chinese Journal of Population,Resources and Environment》 2009年第4期59-63,共5页
Nepal is one of the top three exporters of larger cardamom (Amomum subulatum Roxb.) in the world market contributing largely to the Nepalese economy. Sub-Himalayan range of hilly area of eastern Nepal is popular for... Nepal is one of the top three exporters of larger cardamom (Amomum subulatum Roxb.) in the world market contributing largely to the Nepalese economy. Sub-Himalayan range of hilly area of eastern Nepal is popular for large cardamom cultivation. Being similar phytogeographical and ecological setting, cultivation has begun in hills of Kathmandu Valley however land suitability needs to be evaluated with reference to specific need of the crop. Kathmandu is a valley with alluvial bottom and altitudinal range between 1200 and 2730m above sea level having cool to warm temperate climatic range. Varieties of aspects and slope gradient have potentiality for the large cardamom cultivation. Aim of the study was set to categorize available land area in the range of suitability for large cardamon cultivation on the basis of physical characteristics of the land and ecological need of crop. Land evaluation methodology has been designed along with site specific amendment in FAO framework (1976). Land use map in scale of 1:25 000 was used in geographic information system environment. Suitability was done through map overlaying methods. Aim of the study was set to categorize available land area in the range of suitability categories for large cardamom cultivation based on physical characteristics of the land matching with ecological need of crop. Analysis of data shows that altitudinal range at uplands of Kathmandu Valley and annual average rainfall and temperature are found to be within suitability range for Amomum subulaturn cultivation. Sandy loam soil, slightly acidic in nature with gentle sloping land of about 5-8° provides highly suitable condition. Result showed that more than one-third of total land area above 1800 m of altitude is suitable. Selectively, of the total area, 5% are north facing slope, 13% gentle slopes are highly suitable. 16% lands with north east orientation are moderately suitable. Most of the land areas which are marginaly suitabile for vegetable and cereal crops are highly suitable for large cardamom. Hills of northern boundary hills found to be suitable due to more rainfall distribution pattern compared to southern boundary hills. Therefore, land evaluation also identifies limitations and input requirements for sustainable production. 展开更多
关键词 land suitability GIS Amomum subulatum Roxb
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水利风景区旅游规划研究——以湖南攸县酒仙湖景区概念性规划为例
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作者 张宝铮 《农业科技与信息(现代园林)》 2010年第5期60-62,共3页
从酒仙湖景区的旅游资源分布和特点,以及旅游市场分析和发展策略等方面分析,对酒仙湖景区景点共性加以提炼,总结出生态脉、水韵脉、文化脉三条主线,以三条文脉综合构筑成酒仙湖独具的特色,象征着中国传统"天人合一"的思想。本... 从酒仙湖景区的旅游资源分布和特点,以及旅游市场分析和发展策略等方面分析,对酒仙湖景区景点共性加以提炼,总结出生态脉、水韵脉、文化脉三条主线,以三条文脉综合构筑成酒仙湖独具的特色,象征着中国传统"天人合一"的思想。本着"赏自然生态、探水韵奥秘,品历史悠长、享天人和谐"之理念,体现景区"玩水、赏景、休闲度假"的主题,打造长株潭度假休闲胜地。 展开更多
关键词 旅游 生态脉 水韵 文化 休闲
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Design and Test of Inductive Adder Pulse Generator for KickerMagnet 被引量:2
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作者 刘超 尚雷 +1 位作者 刘祖平 郭亮 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2008年第z1期40-42,共3页
The cell circuit design and test of inductive adder pulse generator for kicker magnet are presented in the paper.The 3.3kV IGBT,a large dimension nanocrystalline core and a 2.5kV 50uF energy storage capacitor are used... The cell circuit design and test of inductive adder pulse generator for kicker magnet are presented in the paper.The 3.3kV IGBT,a large dimension nanocrystalline core and a 2.5kV 50uF energy storage capacitor are used. The multi-channel trigger IGBT driver board is designed.IGBT failures under short circuit condition and protection scheme are explored.The multi-cell prototype is designed.The waveforms of experiments are presented.It turns out that the rise and fall time of the output pulse is fast and the pulse width is adjustable.The maximum current of pulse reaches 2kA.It satisfies the higher requirement of beam injection technology. 展开更多
关键词 pulse generator CPLD solid state modulator inductive adder kicker
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Preliminary Study of the All-Solid,High-Power,Long-Pulse Pulse Generator Based on Magnetic Switch
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作者 杨实 杨汉武 +1 位作者 钱宝良 钟辉煌 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2008年第z1期292-294,共3页
The common characteristics of most capacitive energy storage systems are the use of gas switch,while the limitation of the recovery of gas switch and ablation of electrode lead to low repetition rates and short life.T... The common characteristics of most capacitive energy storage systems are the use of gas switch,while the limitation of the recovery of gas switch and ablation of electrode lead to low repetition rates and short life.The widely researched technology of magnetic pulse compression has great perspective in long life,high average power and high repetition rates in the pulsed power system.Through the theoretical analysis and simulation of the parameters of the BOOST circuit,the LC circuit and magnetic compression circuit,the pulse generator circuit based on the BOOST circuit,the LC circuit,the pulsed transformer and the magnetic switch is designed,simulated and optimized by Pspice. The output pulse has 55kV voltage and 500ns pulse-width. 展开更多
关键词 magnetic switch all-solid pulse generator
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Visualizing Patterns of Genetic Landscapes and Species Distribution of Taxus wallichiana(Taxaceae),Based on GIS and Ecological Niche Models 被引量:7
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作者 于海彬 张镱锂 +1 位作者 高俊刚 祁威 《Journal of Resources and Ecology》 CSCD 2014年第3期193-202,共10页
The Chinese yew(Taxus wallichiana),which is widely distributed in the Himalayas and in southern China,is now on the edge of extinction.In order to understand the evolutionary processes that control the current diver... The Chinese yew(Taxus wallichiana),which is widely distributed in the Himalayas and in southern China,is now on the edge of extinction.In order to understand the evolutionary processes that control the current diversity within this species at the genetic and ecological levels,its genetic patterns and range dynamics must first be identified and mapped.This knowledge can then be applied in the development of an effective conservation strategy.Based on molecular data obtained from 48 populations of T.wallichiana,we used GIS-based interpolation approach for the explicit visualization of patterns of genetic divergence and diversity,and a number of potential evolutionary hotspots have been specifically identified within the genetic landscape maps.Within the maps of genetic divergence and diversity,five areas of high inter-population genetic divergence and six areas of high intra-population genetic diversity have been highlighted in a number of separate mountain regions,and these evolutionary hotspots should have the priority to be protected.Furthermore,four geographical barriers have been identified: the eastern Himalayas,the Yunnan Plateau,the Hengduan Mountains and the Taiwan Strait.According to ecological niche modeling(ENM),the populations of T.wallichiana within the Sino-Himalayan Forest floristic subkingdom experienced westward expansion from the periods of Last Inter-glacial to Last Glacial Maximum(LGM).Following the LGM,the distribution range overall became reduced and fragmented.These findings challenge the classic mode of contraction-expansion in response to the last glaciation.In conclusion,our findings suggest that the changes in geographical landscapes and climate that occurred during the Quaternary resulted in current genetic landscape patterns. 展开更多
关键词 genetic landscape PHYLOGEOGRAPHY GIS Ecological Niche Models(ENMs) HIMALAYAS
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Dynamic analysis of a stage-structured predator-prey system with disturbed time delay and birth pulse
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作者 Weihua Wang Zuoliang Xiong Fang Wang 《International Journal of Biomathematics》 2014年第4期35-50,共16页
In this paper, a stage-structured predator prey system with birth pulse and disturbed time delay is investigated. The conditions of the prey-extinction periodic solution of the system which are globally attractive hav... In this paper, a stage-structured predator prey system with birth pulse and disturbed time delay is investigated. The conditions of the prey-extinction periodic solution of the system which are globally attractive have been obtained. Furthermore, the sufficient corlditions for the permanence of the system are established. Finally, numerical analysis is given to confirm the theoretical results. 展开更多
关键词 Birth pulse disturbed time delay STAGE-STRUCTURE prey-predator model.
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