地形起伏度最佳分析区域预测模型

地形起伏度指分析区域内最高点和最低点之差,反映宏观区域内地形的起伏特征,是描述地貌形态的定量指标。确定最佳分析区域是地形起伏度提取算法的核心步骤,以及决定地形起伏度提取结果有效性的关键。本文以全国范围内随机选取的78个实验区域、三种不同尺度的DEM数据作为实验对象,分别进行系列分析区域尺度的地形起伏度计算,建立了基于微观地形特征因子的地形起伏度最佳分析区域预测模型。实验表明：相同区域、不同尺度的DEM数据提取的地形起伏度存在差异,DEM尺度相差较小时,地形起伏度的差异也较小;地形起伏度和实验区域的最大高程、区域高差、平均坡度和平均坡度变率等地形特征因子存在强相关关系;当置信水平为0.05时,预测模型拟合参数的准确率达到95%以上,证明预测模型可以有效地确定最佳分析区域的取值范围。     

用GPU提速地震资料单程波有限差分叠前深度偏移(英文)

复杂介质情况下,地震波延多路径传播,此时基于波动方程延拓的深度成像方法,相对于Kirchhoff方法能够获得更为精确的成像效果,但是,该深度偏移方法由于高昂的计算消耗阻碍了它在生产中的应用。譬如,叠前深度偏移计算需要大规模的计算机集群,占地面积和电能消耗大。本文介绍了应用一种新的GPU计算架构来辅助CPU进行偏移计算。基于新架构的波动方程深度偏移提高了计算效率,而且机器占地面积和电能消耗也大幅度减少。本文以有限差分波动方程深度偏移为例,介绍了其编程模型和程序优化环节,提高了深度偏移计算效率。2D和3D测试表明,与相同单位个AMD2.5GHz CPU计算相比,该架构下的有限差分波动方程叠前深度偏移计算效率提高至少35倍。     

Proposals for the masses of the three largest asteroids,the Moon-Earth mass ratio and the Astronomical Unit

We propose to the NSFA (the IAU Working Group on Numerical Standards for Fundamental Astronomy) the following representative values and realistic uncertainties for the masses of the three largest asteroids (Ceres, Pallas, Vesta), to be used as the current best estimates:

AMS dating of insect chitin – A discussion of new dates,problems and potential

Results from AMS dating applied to insect chitin from a variety of contexts and different preservation conditions and retrieval methods are presented. Secure contexts, which include other dated organic material from different geographic locations ranging from Egypt to Greenland and different chronological periods, from Lateglacial to Medieval, have been used. In addition, insect species with different dietary requirements have been selected for dating purposes in order to provide an understanding as to whether diet plays a role in the chitin dating results. Dates from each context/site are discussed separately in the context of their stratigraphy and/or archaeology. Our research concentrates on the results from pre-treatment methods which require small quantities of chitin as these could be applied in a variety of Quaternary and archaeological contexts. The dates from carbonised and desiccated remains where no chemicals had been involved in storage fell within the range of dates from other organics or the archaeology. Although some of the dates from waterlogged contexts were successful, problems were encountered and these have been linked with long term storage in various alcohols of uncertain provenance. Whilst short term immersion in paraffin (kerosene) and alcohols during processing probably has no impact, it is recommended that chitinous material for dating be stored in acidified distilled water. Our results demonstrate the potential of chitin as a dating medium and provide a basis for its wider application.     

A hidden suture within the northern Paleotethyan margin: Paleogeographic/paleo-tectonic constraints on the late Paleozoic 'Veles Series' (Vardar Zone,North Macedonia)

There is little consensus in characterizing the effects of the migrated late Pan-African/Lower Paleozoic configuration (western Paleotethys and precursory Paleozoic oceans) and its Variscan, late Variscan, and Eo-Cimmerian involvement. Constrained by a limited choice of the geological, biostratigraphical, and paleogeographical constraints, the focus of this regional geological synthesis is the little-known Devonian – Lower Carboniferous polymetamorphic 'Veles Series' (southern Vardar-Axios Zone, Northeast Mediterranean). Kinematic reconstructions indicate that the drifted carbonate platform assemblage of the 'Veles Series' including its Lower Carboniferous collision occurred along an active margin of southwestern Moesia, Laurussian foreland. Despite the fact that the dominant, low-grade metamorphic imprint across the 'Veles Series' is compatible with the ‘soft’ Eo-Cimmerian docking (i.e. Triassic), the documented Lower Carboniferous age suggests a Variscan involvement.A distinctive Late Paleozoic age is consistent with the north Gondwana and Variscan developments, reflected by the peculiar protoliths pallet portraying the presence of the oceanic crust to deep-marine equivalents. Accommodated to the west (paleo-south) of the late Cadomian Serbo-Macedonian Unit (a segment of the former peri-Gondwanan terrane assembly) and to the north of the Cimmerian Minoan system (East Mediterranean), the 'Veles Series' reflects a migrated rift to carbonate platform system. Despite the significant Alpine overprinting, based on this regional geological synthesis we propose that the 'Veles Series' is a 60 km-long suture segment documenting a so far rather poorly explored Variscan segment of the Paleotethyan lithosphere exposed within Balkans/Northeast Mediterranean.     

中国南海莺－琼盆地油气源对比的成熟度证据

中国南海莺－琼盆地油气源对比的成熟度证据陈军红，傅家谟，盛国英，周毅（中国科学院广州地球化学研究所，广州５１０６４０）张启明（中国海洋石油南海酉部公司石油勘探开发研究院，广东湛江５２４０５７）关键词中国南海，莺－琼盆地，成熟度，油气源油气源对比对含油...     

我国棉花主产省区比较优势分析

1992-1998年平均，我国12个棉花主产省（区）的粮棉单产比和植棉相对效益分别为1.94-7.24和0.95-5.41，经统计分析，这一单产比和相对效益每上升1，一个省1999年与1992年棉花产量之比就分别下降34.0个百分点、上升48.3个百分比，据此比较优势分析，在1999年我国棉花总产下调的形势下，甘肃、新疆宜保持原有产量水平、江苏、浙江、山东、河北、四川5省宜适当下调，而江西、安徽、河南、湖南、湖北5省则宜酌情处理。基于近期国际棉花市场形势的变化，作者认为，与其它省份一样，2001年甘肃、新疆的棉花产量也有较大的上调空间。     

基于GIS不规则单元划分及其地质信息提取系统

地质单元（尤其是不规则单元）划分及地质信息提取是矿产资源定量预测的基础性工作，用通用型GIS软件完成这项工作时有许多限制。如何在较为成熟的商用GIS软件的基础上开发出专用于单元划分及信息提取的计算机系统，是更有效地进行矿产资源定量预测必须解决的问题。从这个目的出发，讨论GIS的不规则地质单元划分及地质信息提取系统的设计及实现过程。     

望湘岩基南部单元—序列体制的探讨

笔者在前人资料的基础上,通过部分野外调查工作,应用侵入体一单元一序列三级体制,将望湘岩基南部侵入体重新厘定,归并为8个单元,组合成两个序列。认为这两个序列是相隔4 Ma的同源岩浆两次脉动式上侵的结果,8个单元是两次岩浆上侵后分别结晶分异的产物。根据野外的接触关系,确认汉家山单元(B岩型)的定位时间晚于坝头岭单元和朱家冲单元(C岩型)。并依据各单元的矿物成分、化学成分、微量元素含量的变化,重新厘定了岩浆的演化顺序。     

Convergence or divergence?: Status and prospects for US climate strategy

The objective of this paper is to assess recent developments and prospects for future changes in United States (US) climate strategy. In doing so, the paper explores some of the key factors that have shaped strategies and policies to date, distinguishing between factors related to institutional and governance structures, linkages between science and policy, energy technology and the role of interest groups. Against this background, the paper attempts to explore future development paths for US climate policy. More specifically, the paper assesses opportunities for policy changes compared to the preferences of the current administration, and the prospects for future linkages between US and international climate change strategies. In brief, the paper argues that substantial changes are unlikely to take place in the near to medium term, leaving open, however, the possibility of wide-ranging changes in domestic politics or major incidents that could facilitate a shift in the perceived need for near-term action.