礁滩体与建设性成岩作用

礁、礁丘、丘同属碳酸盐建隆,礁、滩是重要勘探目的层。但各自在沉积组分、组构、环境和时空分布,以及油气地质条件上迥然不同,因而无论从理论还是勘探实践上,都有必要将其各成体系划分开来。礁滩自身为好储集岩,当建设性成岩作用叠加后可形成好的储层。碳酸盐岩优质储层形成,主要受沉积微相与建设性成岩作用两大因素控制。前者是基础,并以高能的礁滩相带为最好;后者主要包括破裂、白云石化和溶蚀三大类,并以白云石化或溶蚀为最优,其中的溶蚀分布最广泛、影响最深刻而对优质储层形成起决定性作用。礁滩储层中的古岩溶类型最为丰富多彩,包括同生期、准同生期、表生期和埋藏期热流体岩溶的所有类型,白云岩化礁滩体也不例外。其中,同生-准同生期岩溶的形成机制与礁滩沉积时高频层序旋回向上变浅序列的短暂暴露淋溶有关,表生期岩溶则受控于礁滩沉积后三级层序旋回Ⅰ型界面的暴露淋溶。由此,导致礁滩储层中除了可以也是(碳酸盐岩中)唯一保存原生孔隙外,还发育了次生溶蚀孔洞缝和大型溶洞。礁丘、灰泥丘尤其是丘间洼地中发育高有机质丰度烃源岩;它们自身没有有效的原生孔隙,但岩溶作用可以形成次生孔隙。     

计算几何在地图综合中的应用

地图综合是计算几何中的一个应用问题。计算几何是有效的几何基本规则和算法,为地图目标间的复杂空间关系提供了强大的描述和分析依据。文章讨论地图综合中的条件和要求,尤其提出了比例尺缩小造成地不可感知性,而引起选取、目标拥挤、化简和符号化带来的相交等三个关键问题。根据计算几何的Voronoi、Delaunay等数据结构,简要探讨了目标选择、目标聚类和一致性化简的方法。     

国内外城乡统筹研究进展及其地理学视角

城乡统筹是中国当前针对城乡问题提出的美好愿景,其实现过程成为学术界研究的热点,地理学因其区域研究方面独特优势成为城乡统筹研究的重要学科.总结了国外城乡关系的发展过程、经典理论、研究特点和新趋向,国内城乡统筹研究现状、发展目标及主要研究特点;评析了国内外地理学有关城乡统筹问题的主要研究内容和方向,指出其不足之处;提出未来发展趋势.     

河南省安濮鹤三市人口集中问题研究

在推进城镇化和工业化过程中,人口有效集中一直是一个战略性问题.2008年以来,河南省通过建设产业集聚区,积极探索促进人口集中的具体途径和方法.系统调研了河南省安阳、濮阳、鹤壁三市产业集聚区建设所引发的人口集中的主要做法:积极拓展城镇发展空间,促进和扩大就业,提升人口承载能力,不断完善社会保障体系.分析了人口集中效应,指出了人口集中存在的问题,提出了促进人口科学集中的对策:持续提升认识,促进人口集中;持续建设产业集聚区,支撑人口集中;持续推进新型城镇化,引导人口有序集中.     

荷叶塘陨石岩矿特征及化学-岩石类型研究

荷叶塘陨石是1998年降落的一块普通球粒陨石。本文在对荷叶塘陨石的岩石学和矿物化学特征分析的基础上,划分了荷叶塘陨石的岩石类型和次级岩石类型。荷叶塘陨石橄榄石的Fa值在0.6-48.8之间,平均值为23.2,PMD为60.1%;低钙辉石的FS值在0.6-49.0之间,平均值为9.1,PMD为97.5%。结合橄榄石Fa值的PMD与次级岩石类型关系、橄榄石中的Cr含量、铁纹石中富Ni颗粒的数量密度等,综合判断荷叶塘陨石的化学-岩石类型为L3.3,由此表明该陨石是一块热变质程度非常低的L型非平衡普通球粒陨石。     

Fractal dimension and fractal growth of urbanized areas

Based on a box-accounting fractal dimension algorithm (BCFD) and a unique procedure of data processing, this paper computes planar fractal dimensions of 20 large US cities along with their surrounding urbanized areas. The results show that the value range of planar urban fractal dimension (D) is 1< D <2, with D for the largest city, New York City, and the smallest city, Omaha being 1.7014 and 1.2778 respectively. The estimated urban fractal dimensions are then regressed to the total urbanized areas, Log (C), and total urban population, Log (POP), with log-linear functions. In general, the linear functions can produce good-fits for Log (C) vs. D and Log (POP) vs. in terms of R₂ values. The observation that cities may have virtually the same D or Log(C) value but quite disparate population sizes indicates that D itself says little about the specific orientation and configuration of an urban form and is not a good measure of urban population density. This paper also explores fractal dimension and fractal growth of Baltimore, MD for the 200-year span from 1792–1992. The results show that Baltimore's D also satisfies the inequality 1< D <2, with D =1.0157 in 1822 and D =1.7221 in 1992. D =0.6641 for Baltimore in 1792 is an exception due mainly to its relatively small urban image with respect to pixel size. While D always increases with Log (C) over the years, it is not always positively correlated to urban population, Log(POP).     

A new discovery of transition rules for cellular automata by using cuckoo search algorithm

This paper presents an intelligent approach to discover transition rules for cellular automata (CA) by using cuckoo search (CS) algorithm. CS algorithm is a novel evolutionary search algorithm for solving optimization problems by simulating breeding behavior of parasitic cuckoos. Each cuckoo searches the best upper and lower thresholds for each attribute as a zone. When the zones of all attributes are connected by the operator ‘And’ and linked with a cell status value, one CS-based transition rule is formed by using the explicit expression of ‘if-then’. With two distinct advantages of efficient random walk of Lévy flights and balanced mixing, CS algorithm performs well in both local search and guaranteed global convergence. Furthermore, the CA model with transition rules derived by CS algorithm (CS-CA) has been applied to simulate the urban expansion of Nanjing City, China. The simulation produces encouraging results, in terms of numeric accuracy and spatial distribution, in agreement with the actual patterns. Preliminary results suggest that this CS approach is well suitable for discovering reliable transition rules. The model validation and comparison show that the CS-CA model gets a higher accuracy than NULL, BCO-CA, PSO-CA, and ACO-CA models. Simulation results demonstrate the feasibility and practicability of applying CS algorithm to discover transition rules of CA for simulating geographical systems.     

基于高灵敏度检波器数据的分频匹配滤波方法及其应用(英文)

具有较高自然频率的高灵敏度检波器在采集数据时可以通过压制低频信号来相对提高高频能量,但这也造成了其低频响应差的问题,如果将高灵敏度数据与常规数据进行优势组合,就可以达到拓宽频带的目的。为此,本文提出分频段匹配滤波的方法,即在保持常规数据低频优势的前提下,对其高频端进行匹配滤波,实现不同频带范围内的优势互补,从而改善地震记录。通过引入不同主频的雷克子波模拟得到具有常规数据和高灵敏度数据特点的理论模型,论证了分频匹配滤波方法的可行性。在对野外单炮地震记录处理中发现,分频匹配滤波方法拓宽了地震记录的有效频带宽度,提高了地震记录的分辨率。     

Displacement and rectification of planetary fluids

Abstract

Laboratory experiments on the decay (spin-up) of fluid motion on the β-plane are compared with theory. Under weakly dissipative conditions, some particles conserve potential vorticity during the entire decay. We also study the rectified mean flow which is produced by the lateral Reynolds Stress when a low frequency force is applied to the planetary fluid. The possible connection of effects with oceanic phenomena is briefly discussed.     

Research on EPS application to very wide highway embankments in permafrost regions

In order to maintain the thermal stability of very wide highway embankments in permafrost regions, the thermal isolation material EPS is often utilized. To examine the effects of this insulation on the China National Highway (G214), two-dimensional finite element analysis of temperature fields was conducted for varying widths of highway embankments with and without EPS insulation. The numerical results show that in permafrost regions the effect of thermal aggregation on asphalt pavement is more obvious when highway embankments are wider, and, specifically for the G214 highway, the insulation should be more than 25 cm thick for 24-m-wide embankments. However, considering other factors such as the structural rationality of the embankments and high engineering costs, it might not be feasible to install EPS insulation in 24-m-wide embankments of the G214 highway when the height of the embankments is less than 3.65 m.