Uplift capacity of single piles: predictions and performance

The paper pertains to the development of a simple semi-empirical model for predicting the uplift capacity of piles embedded in sand. Various pile and soil parameters such as length (L), diameter (d) of the pile and angle of friction (ϕ), soil–pile friction angle (δ) and unit weight (γ) of the soil which have direct influence on the uplift capacity of the pile are incorporated in the analysis. A comparative assessment of the ultimate uplift capacity of piles predicted by using the proposed theory and some of the available theories are made with respect to each other and with reference to the measured values obtained from model tests in the laboratory. For this purpose experimental data have been collected from the literature and also from model tests conducted as a part of the present investigation. The study shows the proposed model has an excellent potential in predicting the uplift capacity of piles embedded in sand that are consistent with model pile test results.     

2003.6.25南昌特大暴雨分析及模拟研究

对2003年6月25日南昌特大暴雨的环流形势、部分物理量作初步成因分析,并在不同初始边界条件下分析其模拟结果,力图对模式改进和预报特大暴雨的着眼点提出一些初步的想法。     

大厚度粗颗粒含水层井损值的确定

依据实际勘探资料,深刻分析了大厚度粗粒含水层井损值的影响因素。认为井损值主要受抽水井井壁管降深和井的最大出水量两个因素的影响和控制,三者之间高度相关,并建立了回归方程,井损值计算结果与实际观测值基本一致,应用效果较为理想。而采用现成的理论方法计算的井损值,由于其加坡系数在野外的不确定性,计算结果与实测观测值往往有着较大的差别。     

全球中、新生代大地构造特征及其演化框架——《全球中、新生代大地构造图》编图研究进展

全球中、新生代大地构造编图是全球构造理论研究的基础和切入点,本文介绍了该图编制思路与方法、数据来源和大地构造区划,并以地球圈层构造为主线,讨论了全球中生代以来水平构造和全球垂向圈层之间的衔接关系,认为大洋中脊和环太平洋边缘俯冲带通过印度洋、北冰洋、特提斯构造域以及南极洲板块发生构造衔接和转换。南极洲板块周缘被洋中脊环绕,并衔接了全球洋中脊在地球南部的离散运动。结合构造赤道理论,分析了全球不同构造背景下的构造单元之间的关系,认为构造赤道是中生代以来全球构造体制大规模调整的产物。在此基础上,从泛大陆裂解,洋陆关系的角度探讨了中、新生代的全球构造演化。     

Cosmological bang as a consequence of a sudden change in the quantum statistics of nuclear matter

An heuristic hypothesis is advanced about dominant Bose statistics during the transition from the radiation era to the matter era in the early universe. It is shown that large scale Bose condensation of matter from baryon-antibaryon pairs is possible, as a result of which a colossal amount of mass may accumulate in a volume of cosmic scale. At a threshold density of matter, the structural bosons decay into the fermions of which they are composed, so that a sudden change in the symmetry of the wave functions of the particles causes a jump from Bose-Einstein to Fermi-Dirac statistics. This involves a large scale phase transition with an enormous pressure jump which may show up as a cosmological bang at the beginning of the matter era. __________ Translated from Astrofizika, Vol. 51, No. 1, pp. 161–172 (February 2008).     

新疆大喀纳斯旅游区游客的生态系统服务消耗研究

生态系统服务消耗是生态经济相关研究领域关注的热点。以新疆大喀纳斯旅游区为实证点,在游客消费的生态系统服务类型分析基础上,利用物质量法与能值分析法,结合调研数据和统计资料,尝试从景区这类较小尺度空间开展游客生态系统服务消耗计量与分析。结果表明：2010年游客生态系统服务消耗总量为2.54×10¹⁹sej;游客食、住、行、游、娱、环卫等结构中餐饮活动的生态系统服务消耗水平最高,占总消耗的46.48%,其次为游憩活动的消耗水平,占总消耗量的27.76%。游客物质产品类生态系统服务的消耗比重最大,占总消耗的44.52%,此类服务中又以食物消耗所占比重最大;生态安全维护类生态系统服务消耗占总消耗的比重为27.72%,此类服务中CO₂固定和废物吸收处理所占比重较大。     

Constraints on big bang models from structure formation

I review the constraints on standard big bang model arising from considerations related to structure formation. I will focus on two specific series of models though similar analysis can be performed for a wider class of models. The first one is a Ω = 1 model with non-zero cosmological constant and the second one is a Ω < 1 model with zero cosmological constant. The observational constraints which I shall discuss include the measurement of the Hubble’s constant, the ages of globular clusters, the abundance of rich clusters, the baryon content of galaxy clusters and the abundance of high redshift objects. These constraints limit the allowed range of the cosmological parameters and allow. for only a small region to survive. In particular, the aesthetically pleasing model with Ω = 1 and zero cosmological constant is ruled out by the observations. It seems necessary to fine-tune the theoretical parameters if they have to fall within the available space. This talk is based on the work in Baglaet al. (1996).     

Canadian Inuit,digital Qanuqtuurunnarniq,and emerging geographic imaginations

Using the Canadian Arctic as a case study this paper explores how Internet-based research can be used to advance area studies in an era of rapid global change. Regions of the world are rapidly changing due to social, technological, and environmental processes, and traditionally marginalized groups are increasingly using digital tools to help shape new geographical imaginations of these regions. Digital research is uniquely capable of analyzing these political uses of digital technologies, to produce a better understanding of how many different stakeholders are shaping emerging geographical imaginations. The Canadian Arctic offers a particularly powerful case study to understand these processes both because it represents a geographic region that is complex, multi-scalar, and rapidly evolving, and also because it is a region in which traditionally marginalized indigenous groups are using the Internet to increase the visibility of their perspectives. This paper develops an innovative methodology, combining computational analysis of ‘big data’ along with traditional forms of qualitative analysis, to analyze representations of the Arctic across the websites of five different organizations. These organizational websites were chosen because each of the organizations has a different relationship to the Arctic, operates at a different geographic scale, has some relevance to areas of the Canadian Arctic in which Inuit live, and has a large website. The analysis successfully reveals how these different organizations use the web to shape different types of geographic imaginations of the Arctic, as well as the types of discursive politics being used by the organizations to push forward their own political goals. The result is a powerful form of area studies capable of highlighting the geographic imaginations and re-imaginations of a complex set of actors operating at many different scales.     

全球新生代安山岩构造环境有关问题探讨

20世纪70～80年代,以Pearce为代表的一批科学家先后提出了玄武岩和花岗岩的构造环境判别图,将构造环境与岩石地球化学特征有机地结合起来,为岩浆岩大地构造环境研究开辟了新途径。但学术界对全球广布的安山岩构造环境及相关地球化学特征问题的讨论则相对不足。本文利用GEOROC 和PetDB 两个数据库对全球新生代安山岩进行数据挖掘,讨论了它们的地球化学特征及形成环境。初步将全球新生代安山岩归属为12个形成构造环境,其中67.71%产出于岛弧、陆缘弧等汇聚板块边缘环境,其余安山岩则形成于大陆板内、大陆溢流、洋岛、大陆裂谷、洋中脊等构造环境。研究表明,常用的玄武岩微量元素判别图以及LILE/HFSE 玄武岩判别图均在一定程度上可用于安山岩成因及环境判别, 暗示安山岩地球化学成分也可用于构造环境的判定。采用大数据思维,探索洋岛安山岩（OIA）和岛弧安山岩（IAA）中地球化学元素的关联关系,从获得的近20 000 个OIA-IAA 判别图中选出lg（Cs/Ta）-lg（Cu/Ta）、lg（CaO/Nb）-lg（Cs/Zr）和lg（Cu/Ta）-lg（Co/Nb）等6个图解,能有效限定它们的构造环境,为安山岩成因及形成环境研究提供了新的思路。这些初步成果说明科学大数据的研究方法可成为岩浆岩构造环境及地球化学研究中的重要有效手段。