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871.
Dispersion of reflectances in air and oil between 400 and 700 nm of a suiteof scolecodont concentrates with known Conodont Alteration Index was determined using a reflected light microscope. Refractive and absorptive indices of these scolecodonts were calculated using their determined reflectances.Morphologically, scolecodonts in carbonate show similar granular morphology to that of graptolites. Fine structural details of scolecodonts can be observed under reflected light.Reflectances, refractive and absorptive indices of scolecodonts at 546 nm increase with increase of the Conodont Alteration Index, indicating that these properties of scolecodonts can be used to determine the maturity of sediments.Dispersion of the optical properties of scolecodonts follows similar trends to those for vitrinite, natural bitumen and graptolites, indicating similar molecular structural changes with increasing maturity. 相似文献
872.
旅大27-2油田是一个多含油层系,各油组原油黏度差异大。东营组为稀油,地面原油黏度4.8-6.0 mPa.s,适合采用电潜泵开采;而明化镇组稠油油藏地面原油黏度1 052.0-5 369.2 mPa.s,地面原油密度0.968-0.989 g/cm3,常规的电潜泵难以正常开采,若采用常规热采方式开采,将会花费巨大的成本。因此尝试以同一油田的下部东营组稀油作为射流泵的动力液,对上部明化镇两口稠油井选择射流泵试验开采。经对该油田两口稠油井A14h、A15h现场应用,油井产量达到ODP配产,生产稳定。这为该类型油田的后续开发积累了经验。 相似文献
873.
874.
中国能源碳足迹时空格局演化及脱钩效应 总被引:12,自引:5,他引:7
利用DMSP-OLS夜间灯光数据和碳排放统计数据,构建碳排放面板数据模型,模拟了2000-2013年中国的碳排放量.运用探索性时空数据分析(ESTDA)框架体系,从时空交互视角分析2001-2013年碳足迹的空间格局和时空依赖动态演化;利用改进的Tapio脱钩模型对3个时间段336个地级单元环境碳负荷与经济增长之间的脱... 相似文献
875.
A two-dimensional steady-state model of light-driven phytoplankton productivity and biomass in partially mixed estuaries has been developed. Effects of variations in river flow, suspended sediment concentration, phytoplankton sinking, self-shading and growth rates on distributions of phytoplankton biomass and productivity are investigated.Numerical simulation experiments show that biomass and productivity are particularly sensitive to variations in suspended sediment concentrations typical of natural river sources and to variations in loss rates assumed to be realistic but poorly known for real systems. Changes in the loss rate term within the range of empirical error (such as from dark bottle incubation experiments) cause phytoplankton biomass to change by a factor of two. In estuaries with adequate light penetration in the water column, it could be an advantage for phytoplankton to sink. Species that sink increase their concentration and form a phytoplankton maximum in a way similar to the formation of the estuarine turbidity maximum. When attenuation is severe, however, sinking species have more difficulty in maintaining their population. 相似文献
876.
Mass segregation in the form of preferential concentration of more massive stars in the central regions of a number of open
star clusters has been known for some time. In this paper, integratedUBV colours in concentric zones have been estimated for 12 nearby open clusters using the observations of individual cluster
members. It is found that the clusters showing pronounced mass segregation also show significant radial variations in the
integrated colours. However, the effects of stochastic fluctuations around the massive portion of the mass distribution function
on the integrated colours should be taken into consideration, if they are present. 相似文献
877.
During the spring seasons of 1983, 1986 and 1987 the development of phytoplankton in Lake Zürich was investigated (from February
to May) using samples taken at short term intervals. The aim was to describe the effects of the short term dynamics of environmental
factors on the algal growth. The results could then be used to discuss the existing theories to assess the start of phytoplankton
growth pulses in spring.
Only 7 to 10 days without wind driven vertical mixing were required in spring to start the first growth pulse, despite of
a still very unstable water column (sometimes inverse thermal stratification). Mainly flagellates andStephanodiscus hantzschii increased their biomass and achieved net growth rates of 0.1 and up to 0.65 d−1 respectively. During such a phase the mixing depth was always smaller than the euphotic depth. Later on, at the start of
the spring bloom (=last growth pulse in spring before the clear water stage), the intensity of vertical mixing as well as
the mixing depth were markedly reduced due to an increase in heat input and low wind. Then flagellates dominated (contribution
up to 75.5% of the areal biomass reaching 60 g fresh weight m−2) and the growth rate rose to a maximum of 0.65 d−1.
Standard models of critical depth considers that there is only a biomass increase if the mixing depth is smaller than the
depth of a water layer positive balanced between production and respiration. This model for determining the beginning of a
phytoplankton growth pulse in spring takes no account of the favorable light conditions for phytoplankton cells at calm and
sunny days in February and March. The newly developed threshold value model takes these situations into account: It assumes
that the phytoplankton biomass increases when the calculated effective light climate is equal or greater than a previously
fixed threshold. The calculations are based on the mean light intensity within the mixed layer at windy days or within the
euphotic depth (z
eu) at calm days. In Lake Zürich a minimum of 0.2 106 J m−2d−1 (=0.9 mol quanta m−2d−1) has to be reached or surpassed in at least 3 days before an exponential increase of algal biomass can occur. The value does
not depend on short term fluctuations in neither radiation nor mixing depth. It seems that this value is rather low comparing
with those of investigations in other water bodies (up to 0.8 106 J m−2 d−1) but high related to values from algal cultures (0.02 106 J m−2d−1). As the weather can only be forecasted a few days ahead with any certainty the period for a more or less accurate prediction
of an algal bloom is restricted to about 1 to 5 days. 相似文献
878.
FENG Wenhao LI Xin 《地球空间信息科学学报》2001,4(1):28-36
1 IntroductionInourcountry ,thesurveyingworkonindustrialobjectshave graduallyincreased .Thoseindustrialobjectsincluderailwayandhighwaytunnels,vari ousoilandgascans ,variousaircraft,shellofcars,largemilitaryantennausedforscoutingstealthplane ,ship ,internalst… 相似文献
879.
结合一个具体工程应用实例,介绍了土钉墙与轻型井点联合基坑支护降水技术的设计方法,并初步总结了该技术的主要特点和应用注意事项。 相似文献
880.
受冲击石英砂岩碎屑分析 总被引:2,自引:0,他引:2
利用二级轻气炮将6mm直径的钢球加速到5~7km/s后撞击石英砂岩靶,利用磁性分选,扫描电镜和X射线衍射等方法对嵌靶受击后形成碎屑进行了矿物分类和鉴别,碎屑主要由石英,高硅玻璃,微量柯石英以及铁碎屑,微细钢球等组成,70%的碎屑分布在0.097~0.90mm范围内,无一弱磁性碎屑约占总重量的92%,其它为强磁性碎屑。 相似文献