赣东北地区前震旦系地层金的原生富集趋势探讨

在分析变质岩的含金性及地球化学性质的基础上，认为与金成矿有关的主要元素均源自前震旦系。指出了金的原生富集趋势和存在的矿源层。为在该区寻找金矿指出了方向     

后方交会法配合可编程计算器在测量放线中的应用

介绍了后方交会及支导线的计算方法，探讨了Casio Fx4500计算器程序的编制，说明后方交会法配合可编程计算程序在道路施工及其它测量放线过程中不仅克服了其路基不平等许多不便之处，而且大大提高了测量放线的速度和精度，值得推广应用。     

Uniting space, ground, and underwater measurements for improved estimates of rain rate

Global precipitation is monitored from a variety of platforms including spaceborne, ground-, and ocean-based platforms. Intercomparisons of these observations are crucial to validating the measurements and providing confidence for each measurement technique. Probability distribution functions of rain rates are used to compare satellite and ground-based radar observations. A preferred adjustment technique for improving rain rate distribution estimates is identified using measurements from ground-based radar and rain gauges within the coverage area of the radar. The underwater measurement of rainfall shows similarities to radar measurements, but with intermediate spatial resolution and high temporal resolution. Reconciling these different measurement techniques provides understanding and confidence for all of the methods.     

The influence of hydrocarbon expulsion on carbon isotopic compositions of individual n-alkanes in pyrolysates of selected terrestrial kerogens

Expulsion of petroleum from source rock is a complex part of the entire migration process. There exist fractional effects on chemical compositions in hydrocarbon expulsion. Does the carbon isotopic fractionation occur during expulsion and to what extent? Here the influence of hydrocarbon expulsion on carbon isotopic compositions of individual n-alkanes from pyrolysates of selected terrestrial kerogens from Tuha basin and Fushun, Liaoning Province of China has been experimentally studied. The pyrogeneration-expulsion experiments were carried out under semi-closed system. The carbon isotopic compositions of individual n-alkanes were measured by GC-IRMS. The main conclusions are as follows. First, there is carbon isotopic fractionation associated with hydrocarbon expulsion from Type III kerogens in Tuha Basin. There exist differences of carbon isotopic compositions between the unexpelled n-alkanes and expelled n-alkanes from Tuha desmocollinite and Tuha mudstone. Second, there is almost no carbon isotopic fractionation associated with hydrocarbon expulsion from Type II kerogens in Fushun and Liaohe Basin. Third, carbon isotopic fractionation in hydrocarbon expulsion should be considered in making oil-source correlation of Type III kerogens at least in the Tuha Basin. Further studies need to be carried out to determine whether this is true in other basins. Fourth, oil and source at different maturity levels cannot be correlated directly for Type III kerogens since the carbon isotopic compositions of expelled hydrocarbons at different temperatures are different. The expelled hydrocarbons are usually lighter (depleted in ¹³C) than the hydrocarbons remaining in the source rock at the same maturity.     

Characteristics of the Asian–Pacific Oscillation in Boreal Summer Simulated by BCC_CSM with Different Horizontal Resolutions

The summer Asian–Pacific Oscillation(APO) is a major teleconnection pattern that reflects the zonal thermal contrast between East Asia and the North Pacific in the upper troposphere. The performance of Beijing Climate Center Climate System Models(BCC CSMs) with different horizontal resolutions, i.e., BCC CSM1.1 and BCC CSM1.1(m), in reproducing APO interannual variability, APO-related precipitation anomalies, and associated atmospheric circulation anomalies, is evaluated.The results show that BCC CSM1.1(m) can successfully capture the interannual variability of the summer APO index. It is also more capable in reproducing the APO's spatial pattern, compared to BCC CSM1.1, due to its higher horizontal resolution. Associated with a positive APO index, the northward-shifted and intensified South Asian high, strengthened extratropical westerly jet, and tropical easterly jet in the upper troposphere, as well as the southwesterly monsoonal flow over North Africa and the Indian Ocean in the lower troposphere, are realistically represented by BCC CSM1.1(m), leading to an improvement in reproducing the increased precipitation over tropical North Africa, South Asia, and East Asia, as well as the decreased precipitation over subtropical North Africa, Japan, and North America. In contrast, these features are less consistent with observations when simulated by BCC CSM1.1. Regression analysis further indicates that surface temperature anomalies over the North Pacific and the southern and western flanks of the Tibetan Plateau are reasonably reproduced by BCC CSM1.1(m), which contributes to the substantial improvement in the simulation of the characteristics of summer APO compared to that of BCC CSM1.1.     

基于外弹道计算的人影高炮作业安全评估方法

随着经济的高速发展,各个高炮作业点所在地的周边环境已经发生了很大变化,为了进一步提高人工影响天气作业的安全性,针对高炮作业特点提出了一套安全论证方法。推导了弹道计算的方法,在此基础上结合安全射界法和地理信息系统对作业安全性进行了更精确的评估,并给出实例说明。提出用危险系数的方法进行安全性评估,给出了具体的危险系数定义方法,通过评估系统的一次实际作业评估证明了危险系数进行安全性评估的可行性。以该方法进行安全性评估可有效保障人影作业的安全性,为人影作业提供重要的参考。     

Distribution and geochemical significance of trace elements in shale rocks and their residual kerogens

There is a dearth of information about the distribution of trace elements in kerogen from shale rocks despite several reports on trace element composition in many shale samples. In this study, trace elements in shale rocks and their residual kerogens were determined by inductively coupled plasma–mass spectrometry. The results from this study show redox-sensitive elements relatively concentrated in the kerogens as compared to the shales. This may be primarily due to the adsorption and complexation ability of kerogen, which enables enrichment in Ni, Co, Cu, and Zn. For the rare earth elements (REEs), distinct distribution characteristics were observed for shales dominated by terrigenous minerals and their kerogen counterparts. However, shales with less input of terrigenous minerals showed similar REE distribution patterns to their residual kerogen. It is speculated that the distribution patterns of the REEs in shales and kerogens may be source-related.     

Spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015

China has experienced unprecedented urbanization in the past decades, resulting in dramatic changes in the physical, limnological, and hydrological characteristics of lakes in urban landscapes. However, the spatiotemporal dynamics in distribution and abundance of urban lakes in China remain poorly understood. Here, we characterized the spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015 using remote-sensing data and landscape metrics. The results showed that the urban lake landscape patterns have experienced drastic changes over the past 25 years. The total surface area of the urban lakes has decreased by 17,620.02?ha, a decrease of 24.22%, with a significant increase in the landscape fragmentation and a reduction in shape complexity. We defined three lake-shrinkage types and found that vanishment was the most common lake-shrinkage pattern, followed by edge-shrinkage and tunneling in terms of lake area. Moreover, we also found that urban sprawl was the dominant driver of the lake shrinkage, accounting for 67.89% of the total area loss, and the transition from lakes to cropland was also an important factor (19.86%). This study has potential for providing critical baseline information for government decision-making in lake resources management and urban landscape design.     

Spatially uniform specific discharge from headwater to river basins on the Chinese Loess Plateau

Hydrogeology Journal - Although there is a general consensus that spatial heterogeneity is ubiquitous in hydrological responses, it is common practice to assume a constant specific discharge among...