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991.
旅皖国内旅游者消费结构初探 总被引:14,自引:0,他引:14
分析比较了2001年旅皖国内旅游者消费结构的特点和原因,认为国内旅游者消费结构以刚性旅游消费为主,弹性旅游消费比重较低;普遍具有较强的住宿、餐饮消费偏好,购物、娱乐是消费弱项.为引导旅游者关注弹性消费,实现消费结构合理化,促进安徽省旅游业产业结构的优化升级和经济效益的持续增长,应构建形式多样的大众娱乐设施,丰富旅游景区的娱乐功能,提升旅游商品档次和销售能力,建设多功能购物街,多方位营造安全的旅游消费环境. 相似文献
992.
九华山国内客源市场空间结构与出游行为研究 总被引:6,自引:3,他引:6
在实地调查的基础上,分析了九华山国内客源市场空间结构及其演变特征,得出国内客源市场集中程度降低、客源吸引力不断增强、波浪式推进的演变结论,并探讨了九华山旅游行为空间模式主要以单一目的地旅游模式和区域旅游模式为主,根据旅游意向调查结果显示,九华山与黄山在客源市场方面具有较强的互补性。 相似文献
993.
994.
空间结构展示了一个国家建筑科技新成果和实力 ,由于建筑业的特殊性 ,其安全性备受关注。笔者阐述了空间结构的施工特点以及施工中人为错误的成因和对工程的影响 ,通过对人为错误与建筑风险造价关系的分析 ,提出了控制人为错误的对策为 :适当提高结构设计可靠度水平和加强施工过程的管理 ,减少人为错误的发生 ,对遏制工程质量事故具有指导意义。 相似文献
995.
Smith JG 《Environmental management》2003,32(1):77-92
Recovery of the benthic macroinvertebrate community in a small east Tennessee stream impacted by fly ash discharges from a power plant was investigated over a period of 6.5 years. The rate of recovery was greatest in the first 2 years after an initial 75% reduction in coal use led to a similar reduction in ash discharges and associated contaminants; further recovery followed after all fly ash discharges ceased. Recovery of the stream progressed through two phases. In the first phase, which lasted for approximately the first 2 years, most density and richness metrics increased considerably. In the second phase of recovery, the increases in metric values were followed by declines before fluctuating in and out of the lower reference ranges for the metrics. Detrended correspondence analyses and indicator species analyses showed that changes in species composition and community structure were ongoing throughout the second phase. Thus, the first phase was characterized by species additions, while the second phase involved species replacements and shifts in community dominants. Further recovery of the macroinvertebrate community will probably depend on additional flushing of fly ash deposits from the streambed and flood plain, because their continued presence reduces habitat quality in the stream and serves as a potential source of contaminants. Further recovery also may be limited by the availability of vagile species in nearby watersheds. 相似文献
996.
本文调查研究了日本弓背蚁的群体结构和生物学特性,并初步探讨了日本弓背蚁的营养价值及其开发利用对策. 相似文献
997.
本文提出一种崭新的,更加安全、有效、简单、经济,且能适用于不同地震烈度区的结构减震控制体系,包括结构隔震体系,结构消能减震体系,被动和主动减震控制体系,并介绍这种新体系的减震机理、构造方案、试验成果、减震动力理论分析,以及在国内外的最新研究发展和应用情况,包括作者在该领域所取得的最新试验研究、理论和工程应用成果,并以减轻城市地震灾害为目标,探讨了抗震结构今后的发展方向。 相似文献
998.
Comparative Studies on the Usefulness of Seven Ecological Indices for the Marine Coastal Monitoring Close to the Shore on the Swedish East Coast 总被引:1,自引:0,他引:1
The simultaneous behaviour of seven ecological indices(Hurlberts, Margalefs, Menhinicks, Shannons,species number, Jaccards and saprobic index) wasstudied based on phytoplankton data close to the shoreon the East coast of Sweden during the summer 1998.The sampling stations had a similar eutrophicationlevel and were located in bays. Standard phytoplanktondatabases were used in calculating the indices, whichwere later compared using cluster analysis.Hurlberts, Margalefs, Menhinicks, Shannons andspecies number indices, as measure of communitydiversity, produced similar trends which oftendiffered from those based on Jaccards index ofsimilarity. However, the simultaneous use of theseindices was found meaningful as a possible part of themonitoring close to the shore. The application of asaprobic index lead to erroneous conclusions in thestudied case. 相似文献
999.
The varying traffic parameters such as traffic volume, speed, shape and size, and terrain roughness conditions play a vital
role on dispersion of pollutants in the near field of roadways. Simulation experiments were carried out in the Environmental
Wind Tunnel (EWT) to evaluate the traffic induced effects on vertical dispersion parameter (σ
z
) for heterogeneous traffic conditions in the near field of roadways for evaluating the effect of variations in traffic volume,
terrain roughness condition and approaching wind direction. The model vehicle movement system was fabricated and made operational
in the EWT, which allowed the variation in traffic volume, speed and wind road inclination. Sixty-six hydrocarbon tracer experiments
were performed to evaluate σ
z
in the near field of roadways for variable traffic volume, three terrain roughness conditions and two approaching wind directions
(i.e., 90° and 60°). The values of σ
z
for heterogeneous traffic conditions were found to be higher for low roughness conditions in comparison to other two higher
roughness conditions for various traffic volumes and approaching wind directions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
1000.
综述了环境中常见的7种醛类污染物与DNA形成加合物的结构研究现状,包括单核苷酸-醛试管反应、DBA-醛试管反应、细胞培养、动物体以及人体内所产生的加合物结构的研究方法与结论,并对加合物结构研究的难点和发展方向进行了探讨。 相似文献