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581.
582.
N. Kontopoulos 《Mathematical Geology》1984,16(2):207-211
Grain-size spectra maps of sands from beaches of the western Peloponnese are related to statistical parameters and can be used to infer characteristics of the sedimentation process involved which were unresolved by previous statistical analysis. On the basis of similarities in spectral patterns, the studied beaches fall into four groups: A, B, C, and D. The periodicity observed on the sinuous pattern of the spectra map of groups A and B is interpreted as indicating edge-wave activity. Regarding group D, the gradual W—E increase of particle size along the coast suggests a W—E increase of wave energy, which is also reflected by the inclined trend of the spectra map. Lack of periodicity on the contour pattern of group C probably reflects intensive sample-to-sample sorting variation. 相似文献
583.
本文提出了我国核电发展的 4项策略 ,明确了近中远兼顾的 3个层次的发展目标及相关的重点工程。 相似文献
584.
585.
Arbab I. Arbab 《Astrophysics and Space Science》2004,291(2):143-149
We have shown that the phenomenological models with a cosmological constant of the type Λ=β(
) and Λ=3αH
2, where R is the scale factor of the universe and H is the Hubble constant, are equivalent to a quintessence model with a scalar (φ) potential of the formV∝φ-n, n= constant. The equation of state of the cosmic fluid is described by these parameters (α, β, n) only. The equation of state of the cosmic fluid (dark energy) can be determined by any of these parameters. The actual amount of dark energy will define the equation of state of the cosmic fluid.All of the three forms can give rise to cosmic acceleration depending the amount of dark energy in the universe. 相似文献
586.
《The Journal of geography》2012,111(1):13-20
Abstract Long-term collection of soil temperature with depth is important when studying climate change. The international program GLOBE® provides an excellent opportunity to collect such data, although currently endorsed temperature collection protocols need to be refined. To enhance data quality, protocol-based methodology and automated data logging, along with other physical data, were used to collect soil temperature to a depth of one meter. Data show that diurnal and shallow variation ceases at around 50 cm depth. Therefore the need to incorporate deeper depths into the current protocols for heat flux calculations is warranted. The manual methodology was also found to give representative data. 相似文献
587.
资源型区域碳排放影响因素分析——以山西省为例 总被引:1,自引:0,他引:1
碳排放问题是应对气候变化的主要问题,更是困扰资源型区域改革与可持续发展的关键性问题。以山西省为例,采用LMDI分解方法,将碳排放分解为5种影响因素,对山西省碳排放趋势和变化、影响因素做了深入探讨。结果表明:1)山西省未来碳排放增速减缓,排放量将持续增加,生态环境压力进一步加大;2)能源结构效应为负向影响,虽效应值较小,但潜力巨大。而人口规模正向效应值缓慢变大需要关注;3)在产业结构效应方面,工业、交通运输仓储邮政业及批发零售住宿餐饮业部门产业效应为正效应,且有逐年增大的趋势。表明第二产业和第三产业内部结构不合理,产业结构优化有待提高。 相似文献
588.
The paper presents the prediction of total energy production and consumption in all provinces and autonomous regions as well as determination of the variation of gravity center of the energy production, consumption and total discharge of industrial waste water, gas and residue of China via the energy and environmental quality data from 1978 to 2009 in China by use of GM(1,1) model and gravity center model, based on which the paper also analyzes the dynamic variation in regional difference in energy production, consumption and environmental quality and their relationship. The results are shown as follows. 1) The gravity center of energy production is gradually moving southwestward and the entire movement track approxi-mates to linear variation, indicating that the difference of energy production between the east and west, south and north is narrowing to a certain extent, with the difference between the east and the west narrowing faster than that between the south and the north. 2) The gravity center of energy consumption is moving southwestward with perceptible fluctuation, of which the gravity center position from 2000 to 2005 was relatively stable, with slight annual position variation, indicating that the growth rates of all provinces and autonomous regions are basically the same. 3) The gravity center of the total discharge of industrial waste water, gas and residue is characterized by fluctuation in longitude and latitude to a certain degree. But, it shows a southwestward trend on the whole. 4) There are common ground and discrepancy in the variation track of the gravity center of the energy production & consumption of China, and the comparative analysis of the gravity center of them and that of total discharge of industrial waste water, gas and residue shows that the environmental quality level is closely associated with the energy production and consumption (especially the energy consumption), indicating that the environment cost in economy of energy is higher in China. 相似文献
589.
京、津、冀地区的碳排放趋势估计 总被引:2,自引:0,他引:2
通过多种方法相结合,估计了京、津、冀地区2009-2050年的能源碳排放量、水泥工艺碳排放量和森林碳汇量,计算了区域总的碳排放量和净碳排放量。结果表明:1)京、津、冀地区碳排放量都呈现先升后降的Kuznets趋势,森林年碳汇量对碳排放降低影响不明显;2)在自由排放条件下,北京、天津均在2030年前达到碳排放高峰期,河北省及整个京津冀地区的碳排放高峰将延迟到2039年;3)在2050年前,北京、天津年碳汇量将有所降低,河北年碳汇量则上升。 相似文献
590.
城市不同下垫面的能量平衡及温度差异模拟 总被引:2,自引:0,他引:2
城市能量平衡是研究城市热岛效应的物理基础。利用北京市教学植物园2010年的实测数据,设置不同类型下垫面(植被覆盖类型:林地、草地和不透水层覆盖类型:道路、房屋),利用局地尺度城市气象参数化方案模拟并分析了相同气象条件和净辐射通量输入下,不同类型下垫面的显热、潜热通量及蒸散降温效应的差异。结果显示:(1)不同类型下垫面的各能量支出项有明显差异,植被覆盖区域和不透水层覆盖区域的波文比年均值分别为0.28和4.60,且在植被生长季差异较大;(2)城市扩展过程中道路、房屋替换林地、草地的过程,也是显热增加而潜热减少的过程。植被层向不透水层转换的过程中,显热通量年均增加32.74W/m2,潜热通量减少38.87W/m2,储热通量增加7.95W/m2;(3)理论上,植被蒸散的年降温效应使单位面积植被覆盖区域的气温比不透水层区域可低2.63℃。 相似文献