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991.
992.
针对某核电厂环境放射性本底调查项目,在明确调查目的和调查内容基础上,依据相关标准规范,结合调查范围内自然和社会环境状况,形成一套高效、实用的现场工作技术方法,并解决了样品采集、测量参数的设定等一系列关键问题,为后续同类项目的顺利实施积累了宝贵经验。 相似文献
993.
A data assimilation scheme used in the updated Ocean three-dimensional Variational Assimilation System (OVALS),OVALS2,is described.Based on a recursive filter (RF) to estimate the background error covariance (BEC) over a predetermined scale,this new analysis system can be implemented with anisotropic and isotropic BECs.Similarities and differences of these two BEC schemes are briefly discussed and their impacts on the model simulation are also investigated.An idealized experiment demonstrates the ability of the updated analysis system to construct different BECs.Furthermore,a set of three years experiments is implemented by assimilating expendable bathythermograph (XBT) and ARGO data into a Tropical Pacific circulation model.The TAO and WOA01 data are used to validate the assimilation results.The results show that the model simulations are substantially improved by OVALS2.The inter-comparison of isotropic and anisotropic BEC shows that the corresponding temperature and salinity produced by the anisotropic BEC are almost as good as those obtained by the isotropic one.Moreover,the result of anisotropic RF is slightly closer to WOA01 and TAO than that of isotropic RF in some special area (e.g.the cold tongue area in the Tropic Pacific). 相似文献
994.
The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest Guangxi Zhuang Autonomous Region,China,were examined us-ing remote sensing and geographic information system techniques in this paper.The total ecosystem service values de-clined significantly from 1985 to 1990,and then increased slowly from 1990 to 2005,almost equaled to the 1985 level.The ecosystem service values tended to decline from the west to the... 相似文献
995.
Gen-nian Sun 《中国地理科学(英文版)》2000,10(3):231-237
Modern inbound tourism in China has been developing for 20 years, a trend line of inbound tourists in statistical data began
to show. This paper introduces the concept of tourism background trend line, and explores its two functions as a barometer
in demonstrating fluctuation in the tourism economy and as a forecaster in forecasting tourism development. The tourism background
trend line is a new concept, the word “background” derived from environment science, refers to the “trend line” which reflects
the dynamic curve or dynamic equation of tourism development without considering the impact of unexpected incidents. The introduction
of this concept was inspired by Karl Marx’s comments on the relation between value and price. Tourism background trend line
reflects the summary of multiple factors involving tourism resources, tourism demand, population growth, the scale and speed
of economic development, and the spatial interaction between tourism origins and destimations. It demonstrates the natural
and stable trend and the temporal law of tourism development in a country or region. The tourism statistical curve is at random,
susceptible to disruptions and disturbances from serious political, economic and environmental happenings, but it always fluctuates
around the background line. Tourism background line can reveal the potential of a country’s tourism development. Compared
with the statistical line, it can be used as a “barometer” indicating ups and downs of tourism industry in the past. When
naturally extended, the background trend line also can be used for forecasting the trend of tourism development in future.
In this paper, 4 tourism background trend lines of China’s inbound tourists, i. e. foreign tourists, Hong Kong/Macao/Taiwan
tourists, overseas Chinese tourists and total tourists from abroad, were established with statistical data from 1978 to 1996.
And the impacts of the Political Event in 1989 (or Tiananmen Square Incident) on China’s inbound tourism were evaluated. The
result shows that the impact of the Event was not limited within one year, but it stretched over 3 years. The total loss was
20 million in tourist arrivals and $1620 million in foreign currency income. The paper also studied the trend of China’s inbound
tourism in the next 4 years.
Foundation item: Under the auspices of National Natural Science Foundation of China.
Brography: SUN Gen-nian(1961 —), male, a native of Xi’an City, Shaanxi Province, master of science, associate professor. His
research interests include environment science, geography modeling and MIS for tourism. 相似文献
996.
Michael Zemcov Colin Borys Mark Halpern Philip Mauskopf Douglas Scott 《Monthly notices of the Royal Astronomical Society》2007,376(3):1073-1098
In a search for evidence of the short wavelength increment in the Sunyaev–Zel'dovich (SZ) effect, we have analysed archival galaxy cluster data from the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope, resulting in the most complete pointed survey of clusters at 850 μm to date. SCUBA's 850-μm passband overlaps the peak of the SZ increment. The sample consists of 44 galaxy clusters in the range 0 < z < 1.3. Maps of each of the clusters have been made and sources have been extracted; as an ancillary product, we generate the most thorough galaxy cluster point source list yet from SCUBA. 17 of these clusters are free of obvious active galactic nuclei (AGN) and have data deep enough to provide interesting measurements of the expected SZ signal. Specialized analysis techniques are employed to extract the SZ effect signal from these SCUBA data, including using SCUBA's short wavelength band as an atmospheric monitor and fitting the long wavelength channel to a model of the spatial distribution of each cluster's SZ effect. By explicitly excising the exact cluster centre from our analysis, we demonstrate that emission from galaxies within the cluster does not contaminate our measurement. The SZ amplitudes from our measurements are consistently higher than the amplitudes inferred from low-frequency measurements of the SZ decrement. 相似文献
997.
998.
额尔古纳地区中生代火山活动强烈,其主要的活动期间为晚侏罗世至早白垩世(150~100Ma)。根据新的岩石化学、稀土、微量元素、稳定同位素、构造等方面的分析结果得出以下认识:1.该区中生代火山岩来源较深,具幔源特征,岩浆形成在总体呈挤压背景的环境中,使得岩浆在演化过程中混入了大量的壳源物质;2.中生代火山岩大致分两个亚旋回,其中塔木兰沟组(J3t)火山岩和上库力组(K1s)火山岩是同一岩浆亚旋回的产物。 相似文献
999.
Further seismic properties of a spring-block earthquake model 总被引:1,自引:0,他引:1
1000.