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排序方式: 共有2181条查询结果,搜索用时 281 毫秒
981.
在研究矿区地质、水文地质及工程地质条件的基础上,结合矿井的开采情况,分析认为矿区存在的环境地质问题主要是土地占用和破坏,地裂缝,固体废弃物的排放等,并对其危害程度进行了预测。结果表明,评估区植被破坏较少,无明显土地荒漠化(石漠化)现象,占用土地大多为旱地,有轻微水土流失,易于治理和恢复;区内地质灾害危害的可能性大;固体弃土、弃渣(矸石)在暴雨或流水作用下,可能发生泥石流等地质灾害。对矿山环境进行了综合评估,将研究区分为三个大区:影响严重区、影响较严重区、影响较轻区,并分别对各大区的地质灾害特征进行了分析说明。根据地质环境现状提出了生态环境恢复、修建截排水沟、废渣(矸石)的处理等一系列切实综合治理方案。此研究对矿山环境综合治理具有指导性,并对类似矿山环境综合治理能起到一定的借鉴作用。  相似文献   
982.
This paper deals with the prediction of the dynamic response of steel offshore platforms to high energy impacts from typical supply vessels. The contribution of the high modes of a cantilever beam type structure with a concentrated top mass subjected to transverse impact from rigid and deformable strikers is analysed. A procedure to develop simplified equivalent systems for efficient structural response analysis is presented and its reliability tested by comparing the results from the explicit non-linear FE simulations. Effects such as the overall rotation of the installation, plastic deformations in the contact area, different impact locations and different hinge mechanisms are taken into account. It is shown that the use of the proposed equivalent systems with a reduced number of DOF's can provide accurate results at significantly less computational efforts as compared to the FE simulations. The derivation of some parameters of the equivalent dynamic elastic–plastic SDOF/2SDOF systems, however, needs to consider the complexity of the analysed steel frames and perform preliminary non-linear static analyses. Therefore, further studies of different impact scenarios on platforms with different configurations are recommended to augment the results presented here.  相似文献   
983.
Delivering the ambitious renewable energy targets set by the Scottish Government will require significant expenditures. Plans have been set out to develop 1.6 GW of marine (wave and tidal) energy capacity between 2010 and 2020 in the Pentland Firth and Orkney Waters area (off the north coast of Scotland) with construction costs estimated at £6 billion. This paper uses multi-sectoral economic models to explore the impact that these (temporary) expenditures could have on the Scottish economy. It is shown that the standard Input–Output (IO) modelling approach significantly overstates the employment and value added impacts compared to Computable General Equilibrium (CGE) methods—in which short-run scarcity of factors of production are explicitly modelled. CGE results (under myopic and forward-looking model specifications) produce smaller impacts during the timespan of expenditures but, unlike IO methods, identify non-trivial “legacy effects” after the expenditures cease.  相似文献   
984.
The social dimensions of marine protected areas (MPAs) play an important role in MPA success, yet these social dimensions are little understood. We explore the social impacts arising from the establishment of an MPA using Lyme Bay (south west England) as a case study. Through a series of small group semi-structured interviews the social impacts experienced by fishermen (mobile and static gear), recreational users (divers and sea anglers) and recreation service providers (charter boat and dive businesses) were explored. The social impacts expressed varied according to activity in which the stakeholder group engaged. Negative themes included lengthening fishing trips, tension and conflict, fishermen identity, equity and uncertainty in the long-term. Positive themes included improved experiences for both commercial fishermen and recreational users, and expectations for long-term benefits. These impacts need to be understood because they influence stakeholder behaviour. Failure to interpret stakeholder responses may lead to poor decision-making and worsening stakeholder relations. These findings have implications for the success of the MPA in Lyme Bay, but also for the future network of marine conservation zones around the UK. Any assessment of MPA impacts must therefore identify social as well as economic and environmental change.  相似文献   
985.
收集了近年来鳌江口附近海域多个工程不同阶段5个潮位站的3~5年潮位实测数据和部分海流实测资料,通过对鳌江口附近海域的不同年份的水位资料进行潮汐调和常数分析,鳌江近海海域主要为半日潮区,其中M2分潮的振幅在170 cm~193 cm;迟角在260°~280°之间,这些站的2007年、2010年、2011年调和常数分析结果相比,主要的半日分潮M2、S2、N2,全日分潮K1、O1及浅水分潮M4、MS4、及M6等分潮振幅、迟角的最大变化分别在1.8 cm~4.4 cm和3°~7°之间。在初步掌握了鳌江口潮汐潮流特征的基础上,采用无结构的三角形网格和有限体积法的FVCOM海洋数值模型,进行模拟结果验证,计算结果与实测数据符合良好。构建重点年份建设工程合拢产生新的岸线水深的潮汐潮流场,刻画鳌江口建设工程的叠加影响。  相似文献   
986.
Ballast water has been a topic of concern for some time because of its potential to introduce invasive species to new habitats. To comply with the International Convention for the Control and Management of Ships' Ballast Water and Sediments, members of the International Maritime Organization (IMO) must equip their ships with on-board treatment systems to eliminate organism release with ballast water. There are many challenges associated with the implementation of this IMO guideline, one of which is the selection of species for testing the ecological impacts of the treated ballast water. In the United States, ballast water toxicity test methods have been defined by the United States Environmental Protection Agency. However, the test methods had not been finalized in China until the toxicity test methods for ballast water were established in 2008. The Chinese methods have been based on species from three trophic levels: Skeletonema costatum, Neomysis awatschensis, and Ctenogobius gymnauchen. All three species live in broad estuarine and open sea areas of China; they are sensitive to reference toxicants and acclimatize easily to different conditions. In this paper, the biological characteristics, test processes and statistical analysis methods are presented for the three species. Results indicate that the methods for evaluating these three organisms can be included in the ecological toxicity tests for treated ballast water in China.  相似文献   
987.
王秀琴  吴婷芳 《干旱气象》2014,32(6):1003-1006
甘肃敦煌地区气候条件虽然适宜棉花生长,但热量条件处于棉花正常生长适宜指标的下线,对棉花的产量和质量具有较大影响。利用敦煌市国家基准气象观测站1983~2012年农业气象观测资料,统计分析了敦煌棉花全生育期气象条件对棉花的株铃数、单铃重及僵烂铃率、蕾铃脱落率及产量的影响。结果表明:棉花花蕾期气温、花后热量和花期气温、裂铃吐絮阶段灌水量是造成棉花僵烂铃和蕾铃脱落的主要原因。花铃期的平均气温越高,热量越充足,越有利于棉铃数的增加;7月上旬至8月中旬夜温不足降低了棉株矿物质和贮存物的积累速率,导致花蕾及胚珠发育不良,单铃胚珠数减少;盛夏7月中旬高温造成棉铃代谢紊乱,导致单铃不孕,造成株铃数不足和单铃重下降,进而影响棉花产量。  相似文献   
988.
Chinese FengYun-2C(FY-2C) satellite data were combined into the Local Analysis and Prediction System(LAPS) model to obtain three-dimensional cloud parameters and rain content. These parameters analyzed by LAPS were used to initialize the Global/Regional Assimilation and Prediction System model(GRAPES) in China to predict precipitation in a rainstorm case in the country. Three prediction experiments were conducted and were used to investigate the impacts of FY-2C satellite data on cloud analysis of LAPS and on short range precipitation forecasts. In the first experiment, the initial cloud fields was zero value. In the second, the initial cloud fields were cloud liquid water, cloud ice, and rain content derived from LAPS without combining the satellite data. In the third experiment, the initial cloud fields were cloud liquid water, cloud ice, and rain content derived from LAPS including satellite data. The results indicated that the FY-2C satellite data combination in LAPS can show more realistic cloud distributions, and the model simulation for precipitation in 1–6 h had certain improvements over that when satellite data and complex cloud analysis were not applied.  相似文献   
989.
Stakeholder engagement has become increasingly important in research programs focusing on climate change impact on ecosystem services. Communication between researchers and stakeholders, however, is often impaired by linguistic barriers, different priorities, and time constraints. This article examines the organizational aspects of science–stakeholder interactions, focusing on examples from the Swedish forestry sector. The study highlights the need articulated by the Swedish forestry sector for access to scientific knowledge, and we discuss how to present research findings in formats suitable to serve as decision support. Clear communication about common goals, expectations, resources, and time frames is needed in order to reduce the risk of stakeholder fatigue.  相似文献   
990.
连云港围填海工程对海洋生态环境的影响及防治对策研究   总被引:1,自引:0,他引:1  
本文根据连云港近年来围填海造地过程及未来发展趋势,系统阐述了围填海造地对连云港海洋水环境质量、湿地功能、生物多样性、渔业资源以及海岸景观等方面的影响,进而提出了控制围填海造地对海洋生态环境不良影响的对策建议,以期为决策层提供参考依据。  相似文献   
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