“航天清华一号”微小卫星及其图像处理

介绍了“航天清华一号”微小卫星的研究背景和主要技术指标。讨论了星上图像智能处理的方案 ,包括云检测和图像压缩两个部分 ,并介绍了地面的图像处理工作     

锗的原子吸收分析进展

本文对近十年来Ge的原子吸收分析,包括电热法、火焰法、氢化物-火焰法和氢化物-石墨炉法等四个方面的进展进行综合评述。     

(Ca_(0.5),□_(0.5))BaCe_2(CO_3)_4F矿物晶体结构的测定

(Ca0.5□0.5)BaCe2(CO3)4F属于六方晶系,晶胞参数为:a=b=5.093(6),c=23.017(6),r=120°,Z=2。用强功率四圆单晶衍射仪在2=2—65°范围内共收集到821个原始衍射强度数据。晶体结构主要靠重原子法解出,采用空间群P62C,根据344个独立衍射点经多轮最小二乘修正后,获得其全部原子的三维坐标、占位度、各向同性及各向异性温度因子等参数,最终的偏离因子R=0.05。     

湖泊水库湖流模拟系统

在系统研究湖泊、水库各项水动力影响因素的基础上,建立了湖流模拟系统,其中包括水流叠加波浪后波流的共同作用、波浪剩余动量流、风作用剪应力、风吹流以及悬移质扩散分布等。数值模拟中还采用了几种处理技术,并对ADI法进行了双向双步扫描改进。在引滦入津输水工程中的于桥水库湖流计算预报的应用表明,计算结果与现场实测吻合良好,具有计算精度高、收敛快、稳定性好、通用性强等优点。     

激光粒度分析与传统粒度分析方法相关对比

对 4 1个样品的激光法与传统法 (筛析部分—沉析部分 )的粒度分析成果 (粒级百分含量、粒度参数和海陆相样品的粒度成果 )作了相关对比。找出 2种分析方法之间的内在联系 ,以期在将来的粒度分析中 ,可以通过参数矫正来实现 2法的数据转换。从分析可知 ,海陆相沉积对样品的影响很小。 2种方法的原理不同 ,从而产生了激光法低估粘土部分百分含量的结果     

Major ion geochemistry and nutrient behaviour in the mixing zone of the Changjiang (Yangtze) River and its tributaries in the Three Gorges Reservoir

Inorganic ions and nutrients were measured at different depths of the Xiangxi and Daninghe Rivers to explore the mixing processes of representative bays in the Three Gorges Reservoir (TGR). HCO₃⁻ and Ca²⁺ are the dominant ions. Carbonate weathering is the most important mechanism controlling the ion water chemistry; however, important differences exist between the main channel and its tributaries. Major ion levels in the TGR bays depend on hydrological mixing. Results show that the major ions of Ca²⁺, Mg²⁺, Na⁺, K⁺, Sr²⁺, SO₄²⁻ and Cl⁻ show chemically conservative behaviour during transit through the bays of the TGR. This means the ions can be used as tracers in the same way that salinity is used in estuaries to explore behaviour of other non‐conservative elements and to indicate specific source waters. In contrast, nutrients are not conserved in the mixing zone. The mixing of the main channel and tributaries and biological utilization in backwater reaches were the key factor controlling nutrient distributions in Xiangxi and Daninghe Bays. Copyright © 2010 John Wiley & Sons, Ltd.     

Slope instability mechanisms in dipping conglomerates over weathered marls: Bol landslide,Croatia

In February 2005, a landslide of significant dimensions occurred at Bol on the Island of Brač, in Croatia. The location of the landslide was in a geological structure of weakly bounded conglomerates lying above a flysch, in an area where numerous slides have been previously reported. In the paper the results of a geological engineering investigation of the Bol landslide are presented. The investigation results show that the landslide was triggered by a combination of improperly started earthworks, an increase in air temperature in days preceding landslide that caused snow melt, and abundant rainfall, but the primary cause of the landslide was weathering of the flysch. In other words, despite the fact that contact between the flysch and the conglomerates slopes is in approximate correspondence with the slope of the hillside, the landslide surface was not in contact between the conglomerates and marl, but deeper in the flysch, provoked by the penetration of the weathering front into the flysch. Numerical modelling results were able to reproduce this mechanism by incorporating strength degradation into the weathered zone, determined by field investigation. The results of the research can be used to predict potential slides not only in the area under study.     

Assessment of equity principles for international climate policy based on an integrated assessment model

Natural Hazards - Defining an internationally equitable distribution of the burdens of reducing greenhouse gases has been one of core concerns for as long as climate policies have been debated....     

Pore-Throat Combination Types and Gas-Water Relative Permeability Responses of Tight Gas Sandstone Reservoirs in the Zizhou Area of East Ordos Basin,China

With the aim of better understanding the tight gas reservoirs in the Zizhou area of east Ordos Basin, a total of222 samples were collected from 50 wells for a series of experiments. In this study, three pore-throat combination types in sandstones were revealed and confirmed to play a controlling role in the distribution of throat size and the characteristics of gas-water relative permeability. The type-Ⅰ sandstones are dominated by intercrystalline micropores connected by cluster throats, of which the distribution curves of throat size are narrow and have a strong single peak(peak ratio 30%). The pores in the type-Ⅱ sandstones dominantly consist of secondary dissolution pores and intercrystalline micropores, and throats mainly occur as slice-shaped throats along cleavages between rigid grain margins and cluster throats in clay cement.The distribution curves of throat size for the type-Ⅱ sandstones show a bimodal distribution with a substantial low-value region between the peaks(peak ratio 15%). Primary intergranular pores and secondary intergranular pores are mainly found in type-Ⅲ samples, which are connected by various throats. The throat size distribution curves of type-Ⅲ sandstones show a nearly normal distribution with low kurtosis(peak ratio 10%), and the micro-scale throat radii(0.5 μm) constitute a large proportion. From type-Ⅰ to type-Ⅲ sandstones, the irreducible water saturation(Swo) decreased; furthermore, the slope of the curves of Krw/Krg in two-phase saturation zone decreased and the two-phase saturation zone increased,indicating that the gas relative flow ability increased. Variations of the permeability exist in sandstones with different porethroat combination types, which indicate the type-Ⅲ sandstones are better reservoirs, followed by type-Ⅱ sandstones and type-Ⅰ sandstones. As an important factor affecting the reservoir quality, the pore-throat combination type in sandstones is the cumulative expression of lithology and diagenetic modifications with strong heterogeneity.