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排序方式: 共有218条查询结果,搜索用时 31 毫秒
181.
182.
西部农村沼气建设现状与对策 总被引:3,自引:0,他引:3
阐述了大力发展西部农村沼气建设的必要性和可行性.并就如何发展沼气建设提出了一些建议和解决方案。 相似文献
183.
吉林西部碱尘的通量与物质特征分析 总被引:1,自引:0,他引:1
选择吉林西部两个典型地区,抽样采集碱尘样品,根据实测结果对日常形成的碱尘进行了通量测定;依据两个采样点的自然地理状况和实测采样记录,提出了吉林西部碱尘具有两种源区类型的认识,即以大布苏湖为代表的萎缩湖泡型和以姜家甸草场为代表的草场退化型。同时,通过对比分析不同时间和采样点的碱尘通量及源区特征,提出了吉林西部碱尘通量与风力条件、日照条件、pH值、物理性粘粒比例正相关,与植被覆盖度、地表物质粒级负相关。对碱尘元素分析结果表明,Ca、Na元素含量明显偏高,Fe、Al元素含量变化则较大;碱尘组成元素含量由多到少的顺序为:Ca、Na、Fe、Al、K、Mg、Ti,与普通尘暴元素组成有着明显的差别。 相似文献
184.
E. J. Anthony 《Journal of Coastal Conservation》1997,3(2):169-178
Beach conservation and management on the high-value French Riviera in southeastern France have had mixed fortunes in shoreline
economic development strategies over the past half century. Prior to 1965, socio-economic growth related to immigration and
tourism resulted in considerable pressure on the coastal zone, leading in particular to beach erosion and degradation of beach
environmental quality. Between 1965 and 1980, over 20% of the 132 km-long French Riviera was permanently altered through the
implantation of yachting harbours and reclamation fill structures, while beach-based recreation had a rather low ranking as
a development choice, except in the two major resorts of Cannes and Nice which exhibit a densely urbanized seafront. On this
preponderantly bold rocky coast, the mediocre recreational value inherited by many of the beaches from the regional geologic
setting, and from development pressures and earlier errors in coastal management, left them vulnerable to appropriation and
so-called ‘valorization’ by yachting harbour and estate developers.
Over the last decade, artificial shoreline development has virtually ceased, in response to several more or less interrelated
factors. These include relative stagnation of socio-economic growth, increasing development and maintenance costs of yachting
harbours, saturation of the yachting harbour market as a result of the burgeoning of new, often cheaper, resorts and of reconversion
of commercial and shipbuilding ports to leisure ports in the Mediterranean, more stringent legislation, since 1986, on the
implantation of residential and major engineering structures on the coastline, pressure for conservation of the cultural and
environmental heritage, and greater demand for beach recreational space. This situation has forced a diversification of shore-based
activities, as it has been realised that better managed beaches may balance economic aspirations while contributing to enhanced
environmental quality and sensible shoreline conservation. This change in strategy has entailed considerable efforts and money
on the improvement of coastal water quality, the provision of amenities for beach-goers, and especially the nourishment of
eroding beaches and the creation of several artificial beaches. The extent to which beaches will continue to play a role in
the sustainable development of French Riviera resorts will depend largely on the capacity of local authorities to maintain
environmental quality in the face of inherited and persistent handicaps such as beach erosion. 相似文献
185.
中国沿海的风暴潮灾及其防御对策 总被引:3,自引:0,他引:3
中国沿海是仅次于孟加拉湾地区的第二大风暴潮重灾区。本文分析了地质时期及历史时期我国风暴潮灾的灾害记录,揭示了中国沿海风暴潮灾的严重性,并讨论了其成因特点和成灾机理,提出了一系列防灾措施和防御对策 相似文献
186.
渤海湾西岸海平面上升威胁的防治对策 总被引:5,自引:2,他引:5
因受全球海平面上升和地面沉降的双重影响,在21世纪末渤海湾西岸海平面将相对上升90~260厘米,广大地区(包括天津市区)将处于大潮平均高潮位之下,自然岸线位置将后撤至津浦线附近.我们提出筑堤防潮引黄放淤提高建筑高程三位一体的治理方案。 相似文献
187.
王晨 《中国环境管理干部学院学报》2006,16(3):101-103
外语教学旨在提高学生的语言交际能力,而用之于交际的语言又是某种文化的反映.文化干扰是教学的难题之一.因而,大学英语教学中要注重培养学生的跨文化交际能力,认识中西文化差异,注重对文化知识的导入. 相似文献
188.
189.
Gardening has become a relevant contributor to the quality of life of suburbanites, as a source of leisure, to build a relationship with nature or to express a particular social identity. Nevertheless, water scarcity in the Mediterranean region has increased concerns about how demand should be managed to face future uncertainties, and watering the gardens has become an element for discussion in urban planning. This contribution presents the findings of a survey of permanent residents and secondary homeowners (n?=?230) in the suburban areas surrounding the city of Girona in the northeast of Catalonia (Spain). The area is a popular national and international tourist destination and a preferred place for second-home owners. We explore the main socio-demographic drivers for choosing an alternative watering source and we analyse if water-harvesting tank sizes properly meet net irrigation requirements. Results show that many water-harvesting tanks are oversized. The percentage of unemployed or retired household members, the estimated irrigation water needs of the garden and the education level directly influence the search for alternative sources of water. Moreover, social variables like interest in gardening, water conservation attitudes and household income indirectly influence the search for alternative sources of water. 相似文献
190.
福建沿海输电线路设计风速取值探讨 总被引:4,自引:1,他引:3
根据福建省崇武气象台1973~2006年的风速资料,分别采用极值Ⅰ型Gumbel分布、极值Ⅱ型Frechet分布、极值Ⅲ型Weibull分布对该地区的风速进行了统计分析。结果表明,该地区发生强风的概率很大,受台风的影响,年最大风速一般发生在7~10月份,且其风速值随着年代的推后有下降的趋势;经柯尔莫格洛夫拟合优度检验,极值Ⅰ型Gumbel分布是该地区的风速概率分布的最优曲线;极端风速是影响沿海输电线路安全的一个重要因素,可采用差异化的设计方法予以考虑。 相似文献