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11.
小说《老人与海》是美国小说家海明威晚年的一部杰作。小说主要叙述了老渔民圣地亚哥出海捕鱼的故事。人们欣赏它是一曲英雄主义的赞歌。而站在当今时代,小说中人与自然之间的复杂矛盾的多维生态关系尤为凸显。文章细致展示小说中人,自然(大海)及海洋生物之间的对话和交锋,分析坚毅的渔夫不能如愿从大海深处带回巨大的马林鱼的根本原因,引领人们对小说潜在生态批评的认识,同时延伸人们正确的生态认知。  相似文献   
12.
对美国民用航空预备队的基本情况及其运行体系、组织体制进行了介绍,并就坚持军民融合、确定民航运力动员建设的目标,坚持平战结合、进一步完善民航运力动员体制,坚持效益优先、着力提高民航系统的战备水平,坚持精确快速、提升信息化民航运力动员能力等方面提出了建议。  相似文献   
13.
Bus stops are integral elements of a transit system and as such, their efficient inspection and maintenance is required, for proper and attractive transit operations. Nevertheless, spatial dispersion and the extensive number of bus stops, even for mid-size transit systems, complicates scheduling of inspection and maintenance tasks. In this context, the problem of scheduling transit stop inspection and maintenance activities (TSIMP) by a two-stage optimization approach, is formulated and discussed. In particular, the first stage involves districting of the bus stop locations into areas of responsibility for different inspection and maintenance crews (IMCs), while in the second stage, determination of the sequence of bus stops to be visited by an IMC is modelled as a vehicle routing problem. Given the complexity of proposed optimization models, advanced versions of different metaheuristic algorithms (Harmony Search and Ant Colony Optimization) are exploited and assessed as possible options for solving these models. Furthermore, two variants of ACO are implemented herein; one implemented into a CPU parallel computing environment along with an accelerated one by means of general-purpose graphics processing unit (GPGPU) computing. The model and algorithms are applied to the Athens (Greece) bus system, whose extensive number of transit stops (over 7500) offers a real-world test bed for assessing the potential of the proposed modelling approach and solution algorithms. As it was shown for the test example examined, both algorithms managed to achieve optimized solutions for the problem at hand while there were fund robust with respect to their algorithmic parameters. Furthermore, the use of graphics processing units (GPU) managed to reduce of computational time required.  相似文献   
14.
对河北省承(承德)赤(赤峰)高速公路在选线设计、施工建设及运营管理整个阶段与茅荆坝自然保护区生态旅游的相关性进行了分析,结果表明:承赤高速公路的选线设计及施工建设对茅荆坝自然保护区生态旅游的资源会产生永久性的破坏和污染,但同时也改善了保护区的交通现状及保护区之间的连通性.有利于生态旅游资源的开发和展现及区域生态旅游网络的建设,此外承赤高速公路通车后原住民会逐步迁出保护区,有利于茅荆坝自然保护区生态旅游资源的恢复。  相似文献   
15.
针对40 t轴重专用铁路制定设计列车荷载图式,研究首先从列车荷载图式和安全储备系数的角度,对重载专用铁路与一般线路的差别进行探讨分析,提出重载专用铁路列车荷载图式的型式以及合理安全储备系数;以现有40 t轴重矿石车为原型,按荷载效应等效的原则将其概化为图式的型式,根据安全储备系数取值建议,将概化图式轴重参数提高10%,形成40 t轴重矿石车列车荷载图式。该图式对于列车的储备在不同跨度范围内较为均衡。同时通过比较荷载效应,掌握图式与国内外现行重载铁路列车荷载图式的差异。  相似文献   
16.
文章通过对古希腊罗马自然法学观点的分析,指出自然法学观中的平等、正义、德性等理念与当今和谐社会的基本特征,具有一定的相似之处,并对构建和谐社会起到一定的借鉴意义。  相似文献   
17.
Contrary to common perceptions, the creation of protected areas does not start when they are officially declared but generally follows a long process. For instance, the Galapagos Marine Reserve (GMR) was not “born” when it was formally announced on March 18th 1998, but several decades before that. Through document analysis and key informant interviews, we applied the “step zero” approach to examine what happened prior to the implementation of the GMR. This study reveals that the GMR did not arise from a social and political vacuum; rather, events took place in the distant past, even centuries ago, influenced the reserve's creation and current status. Its establishment was driven by complex geopolitical, economic, social, and environmental factors from both within and outside Galapagos. Additionally, the process of creating the GMR was convoluted, marked by hidden interests and conflictive political agendas that triggered controversies between users. The making of the GMR was also influenced by the interest in promoting “nature-based” tourism, and the regulations that followed had disadvantaged small-scale fishers. This knowledge about the reserve's pre-implementation phase enables a broader understanding of the current challenges facing the performance of the GMR and points to possible governance interventions needed to enhance its sustainability.  相似文献   
18.
船舶轴系扭振计算和测试实例分析   总被引:7,自引:2,他引:5  
船级社规范对轴系扭振提出了计算和实测的要求。本文对若干轴系固有频率的实测值与计算值不一致的船舶进行了分析,并给出了对影响其相应计算精度的减振器、曲轴、联轴节刚度等扭振参数进行了修正的实例;通过实测,对无阻尼自由振动计算的振型精度亦进行了分析,按振型推算系统响应超规范要求的船舶,可根据实测振幅来调整阻尼参数并用解析计算法来评价轴系扭振特性。结果表明,精确测定出系统的固有频率和振幅,从而核定轴系的扭振参数,是提高扭振计算精度的关键所在。  相似文献   
19.
新建荆州至岳阳铁路在君山区约有46.52km位于东洞庭湖国家级自然保护区实验区范围内。从植被生产力及碳贮量和景观生态体系质量两方面介绍了东洞庭湖自然保护区自然体系的生态环境质量现状,并分析和预测了工程建成后保护区自然体系生物量、碳贮量及生产力的变化、自然体系的稳定状况。认为荆岳铁路的建设对东洞庭湖自然保护区自然体系生态完整性影响较小。  相似文献   
20.
文章以文本细读的方式解析了方方《树树皆秋色》中华蓉的形象,指出小说主人公华蓉这一当代社会文化背景下的知识分子在热爱大自然的生活表象下埋藏的精神困境,以及产生这种精神困境的社会原因。  相似文献   
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