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81.
2008年汶川大地震给四川省旅游业发展在短期内造成了极大困难,但也给当地遗留了大量的地震遗存,拥有重要的科学考查、科普教育和纪念价值。后重建时代极重灾区面临的旅游发展问题大同小异,虽然开发了许多新项目,但问题并没有从根本上解决。从当地自然环境禀赋各异、少数民族文化开发程度低、旅游商品外来化严重、旅游安全等方面分析了面临的各种问题,提出了具有针对性的对策和建议。  相似文献   
82.
基于土地适宜性评价方法,着重选取极限值条件法、AHP层次分析法、加权指数和法对白山市道清沟煤矿区的土地适宜类和土地质量等进行系统综合的分析,判定道清沟煤矿待复垦土地的类型、数量和质量。基于土地破坏现状和适宜性评价结果,提出以工程措施为主、生物化学措施为辅助的土地生态重构对策。  相似文献   
83.
改革开放以来,随着中国农村经济的快速发展,农村环境问题也日益突出,严重影响了社会主义新农村建设的“生产发展、生活宽裕、乡风文明、村容整洁、管理民主”目标和要求的实现,阻碍了农村乃至全国经济、社会和环境的协调发展。加强农村环境保护,是新农村建设的当务之急,是全面建设小康社会和构建和谐社会的迫切要求。文中在现有研究的基础上,考察农村环境问题之现状,从法律视角,深入分析农村环境的问题之所在,提出解决农村环境问题的对策,努力探寻一条与中国农村实际相适合的生态环境保护道路。  相似文献   
84.
The objective of this exposure assessment was to reconstruct cumulative historical exposures for workers who have been exposed to multiple chemicals and chemical groups to better understand a cluster of brain cancers within a research and development lab. Chemicals of interest, including acrylates, bis-chloromethyl ether (BCME), chloromethyl methyl ether (CMME), isothiazolones and nitrosoamines, were selected on the basis of the plausibility of penetrating the blood-brain barrier and the uniqueness of the chemical's biological activity.In a complicated exposure setting such as a chemical R&D facility, multiple exposure estimation methods were needed. First, similarly exposure groups (SEGs) were created for these materials based on department group, time period of the department's existence and function associated with job titles. A probabilistic framework for assessing exposures was developed using Bayesian analysis of historical monitoring data, mathematical exposure modeling and professional judgments of current and former industrial hygienists at the facility were used to reconstruct the exposure history for acrylates, BCME and CMME for each SEG over the time period of interest. Since sufficient measurement data for isothiazolones and nitrosoamines were not available, the exposure histories for each SEG for these chemicals were estimated. This was done using objective formaldehyde levels and subjective employee interviews. The interviews assessed workplace determinants of exposure as distinct surrogates for estimating inhalation and dermal exposures. The exposure assessments by these methods were compared against each other to estimate the potential for exposure misclassification. A job exposure matrix (JEM) was constructed that contained the exposures obtained from above multiple approaches for each of these chemical groups for each SEG for each year of interest. The combination of methods used in this work is a unique and potentially helpful framework that can be used in analogous workplace settings involving multiple exposures with incomplete objective measurement information.  相似文献   
85.
介绍了一种新型汽封在国产600 MW机组节能改造中的应用。改造方案为将汽轮机组原通流部分及轴端的梳齿型汽封改为新型接触式密封齿+蜂窝汽封+铁素体齿的组合汽封,改造后漏汽量大幅减少,高、中、低压缸效率和机组运行的经济性明显提高,对同类型汽轮机通流部分节能改造具有较好的借鉴意义。  相似文献   
86.
A sizeable proportion of adult pedestrians involved in vehicle-versus-pedestrian accidents suffer head injuries, some of which can lead to lifelong disability or even death. To understand head injury mechanisms, in-depth accident analyses and accident reconstructions were conducted. A total of 120 adult pedestrian accident cases from the GIDAS (German in-depth accident study) database were analyzed, from which 10 were selected for reconstruction. Accident reconstructions initially were performed using multi-body system (MBS) pedestrian and car models, so as to calculate head impact conditions, like head impact velocity, head position and head orientation. These impact conditions then were used to set the initial conditions in a simulation of a head striking a windshield, using finite element (FE) head and windshield models. The intracranial pressure and stress distributions of the FE head model were calculated and correlated with injury outcomes. Accident analysis revealed that the windshield and its surrounding frames were the main sources of head injury for adult pedestrians. Reconstruction results indicated that coup/contrecoup pressure, Von Mises and shear stress were important physical parameters to estimate brain injury risks.  相似文献   
87.
Many native bird species in production landscapes of south-eastern Australia demonstrably are declining, with loss of native vegetation as the major cause. Our biodiversity management objectives must be to increase the probabilities of persistence of birds that should occur in the landscape. To do so, there needs to be extensive amounts of new plantings. However, one must be conscious that: (1) new plantings in the impoverished soils and increasing aridity of southern Australia will take many decades to mature, and, also, will offer suitable habitats for a sequence of different species over the course of that maturation process; and (2) much existing vegetation is senescent or will be in a few decades' time. Recent landscape rebuilding models do not explicitly consider maturation time-lags. These hystereses in habitat maturation may create 'bottlenecks' at future times (e.g. in 50yr) that might prevent some species from persisting in whole landscapes even though such landscapes may be much more suitable in 100yr than now. There are several critical issues: (1) species differ in habitat needs and even one species may require different kinds of habitats for foraging and for breeding; (2) landscapes must be conceived, and managed, as spatial and temporal mosaics to allow for persistence of the full set of species that should occupy them, meaning that senescing and replanted habitats may need to be juxtaposed; and (3) in certain particularly problematic landscapes, some highly productive agricultural lands may need to be used for providing habitat because maturation can be fast-tracked in fertile, well-watered locations. The problem is a complex one of scheduling and placement, and its optimization presents major theoretical and analytical challenges.  相似文献   
88.
研究"城中村"改造中土地集约利用的潜力及可行性,探索城市土地集约利用的有效途径,采取文献资料法和实例分析法进行研究。研究结果表明,一方面"城中村"土地利用混乱,效率低下,而且各种配套设施极不完善,给城市建设带来诸多问题急需改造;另一方面,"城中村"大量低效利用的土地经过开发整合具有很大的开发潜力,并具有可行性。"城中村"的改造需要政策支持和科学的规划,才能最大限度地发挥土地价值,达到土地集约利用的三效合一。  相似文献   
89.
Painting an accurate picture of the situation on the ground in countries in crisis is vital for the efficiency of humanitarian aid and reconstruction agencies. This study describes a method for standardising and mapping the plethora of open-source information. The test site for the study is post-conflict Iraq. Important information on aid distribution, reconstruction and security in Iraq can be derived from the reports of humanitarian aid agencies and the media, before being formatted, inserted into a database and mapped. The product is a visual, cartographic structure of otherwise random information, showing which organisations are working in the country, which thematic and geographic areas are being prioritized in the field, and which areas most frequently experience security events. This type of mapping not only highlights the overall working environment within different parts of the country, but it may also serve as a decision-making tool for donors and humanitarian aid agencies planning to deploy personnel.  相似文献   
90.
我国北方地区冬季漫长而寒冷,夏季短暂而温暖,年平均气温低,气温年较差大,开展北方寒冷地区景观水体研究对完善生态系统保护体系及可持续发展具有重要意义。针对北方寒冷地区景观水体环境特征,以牡丹江市南湖水系为例,开展水体水质及水环境特征研究,进行北方寒冷地区景观水体的生态重建与景观修复技术、水资源管理技术、越冬策略研究,并根据工程实践结果,提出北方景观水体水质保障的对策和建议,对北方地区景观水体保护、流域可持续发展具有借鉴意义。  相似文献   
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