基于GIS的斜坡单元划分方法改进与实现

斜坡单元已广泛应用于滑坡易发性制图和地质灾害评价。然而在山间盆地或大型宽谷处,常规方法划分出的斜坡单元与地貌背景难以匹配。依据高程及其衍生变量的基本形态系统和曲率的流域分割原理,基于ArcGIS技术,通过叠加曲率和反转曲率的流域边界,改进了斜坡单元划分方法。结果表明：与常规方法相比,改进方法不仅能够使用山脊线和山谷线以划分斜坡单元,还能利用台地边界和宽谷边界以分割水平地表与倾斜地表;划分出的单元大小相对均匀,单元形状总体介于圆形和正三角形之间。对于水平成分较多的地区,如黄土塬区和水库库区,该方法与传统方法相比,具有较好的应用前景。     

Regional summer temperature decrease against global warming in China, landform effect?

The data of 160 national meteorological observatory (NMO) stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global warming in the past half century. The summer and winter isotherm structures of 1950s and 1990s worked out by interpolation show the isotherm structure variations: the isotherm structure generally moves northward in winter, but in summer it is characterized with separate high-temperature and low-temperature centers and the isotherm structure moves inward the centers with global warming, indicating that the temperature in the highland areas increases but that in the lowland areas decreases in the summer of the duration. The possible mechanism of the basin-centered temperature decrease in summer is discussed in this paper.     

Detecting water yield variability due to the small proportional land use and land cover changes in a watershed on the Loess Plateau,China

Soil conservation practices have been widely implemented on the Loess Plateau to reduce severe soil erosion in north‐central China over the past three decades. However, the hydrologic impacts of these practices are not well documented and understood. The objective of this study was to examine how water yield has changed after implementing soil conservation practices that resulted in changes in land use and land cover in a small agriculture‐dominated watershed, the LuErGou Watershed in Tianshui City, Gansu Province, China. We collected 23 years of hydro‐meteorological data along with three land use surveys of 1982, 1989, and 2000. The land use survey in 2000 suggested that the soil conservation efforts resulted in a 16·6%, 4%, and 16% increase in area of grassland, forested land, and terraces respectively over the two periods from 1982 to 1988 (baseline) and 1989 to 2003 (soil conservation measures implemented). Rainfall–runoff regression models developed for both time periods at the annual and monthly time steps were used to examine the significance of change in water yield in the second time period. The averaged annual run‐off coefficient over 1989–2003 did not change significantly (at the α = 0·05 level) as compared to that in the period 1982–1988. However, we found that soil conservation practices that included re‐vegetation and terracing reduced water yield during wet periods. This study highlights the importance of the precipitation regime in regulating hydrologic effects of soil conservation measures in a semi‐arid environment. We concluded that adequately evaluating the effects of land use change and soil conservation measures on water yield must consider the climatic variability under an arid environment. Copyright © 2009 John Wiley & Sons, Ltd.     

A search for double-peaked narrow emission line galaxies and AGNs in the LAMOST DR1

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) has released more than two million spectra,which provide the opportunity to search for double-peaked narrow emission line(NEL) galaxies and active galactic nuclei(AGNs).The double-peaked narrow-line profiles can be well modeled by two velocity components,respectively blueshifted and redshifted with respect to the systemic recession velocity.This paper presents 20 double-peaked NEL galaxies and AGNs found from LAMOST DR1 using a search method based on a multi-Gaussian fit of the narrow emission lines.Among them,ten have already been published by other authors,either listed as genuine double-peaked NEL objects or as asymmetric NEL objects,and the remaining ten are original discoveries.We discuss some possible origins for the double-peaked narrow-line features,such as interaction between jet and narrow line regions,interaction with companion galaxies,and black hole binaries.Spatially resolved optical imaging and/or follow-up observations in other spectral bands are needed to further discuss the physical mechanisms at work.     

中国成菱镁矿区带与关键科学问题

我国菱镁矿资源丰富,储量巨大,目前位居世界首位.类型上以晶质菱镁矿为主,便于开发利用.晶质菱镁矿又以沉积变质型为主,集中分布在辽东地区,形成了世界级的大型—超大型菱镁矿集中区和生产基地,其次为成因上与超镁铁质杂岩密切相关的热液交代型和风化残积型,青藏班公湖成矿带可作为我国湖相沉积型菱镁矿找矿的重要靶区.本次在对全国62处菱镁矿矿产地资料系统梳理的基础上,深入总结了全国菱镁矿的成矿规律,进一步划分了菱镁矿的矿床类型,并划分出13个成菱镁矿带,编制了“中国菱镁矿成矿规律图”、“中国菱镁矿成矿体系图”和“中国成菱镁矿带分布图”等图件,为我国菱镁矿资源潜力评价的预测工作提供了理论依据.同时,本文对我国辽东超大型菱镁矿的成因机制问题和菱镁矿中镁的物质来源等关键科学问题展开了探讨.     

Effect of Sacrificial Anode Protection for Steel Pipe Piles at Dandong Port

The sacrificial anode protection system for the steel pipe piles of the 3rd berth of Dandongwharf at Dandong port has operated for eight years.In this paper,the program design and the protectioneffect of the sacrificial anode protection system are presented.The results of various,inspections show thatthe piles are protected very satisfactorily.     

新疆西天山博罗科努成矿带岩浆岩时空分布、构造演化与成矿响应

博罗科努成矿带位于新疆西天山北缘,近年来找矿成果突出。在充分收集前人研究成果的基础上,初步总结了博罗科努带岩浆岩时空分布特点及其年龄资料,重点分析了与成矿关系密切的晚古生代岩浆作用的性质。博罗科努带地质历史与北天山洋的演化密切相关,前寒武纪统一基底形成,北天山洋打开。寒武纪为被动陆缘环境,北天山持续扩张。奥陶纪北天山洋向伊犁地块之下俯冲,该带进入大陆弧演化阶段。泥盆纪—晚石炭世早期为俯冲高峰期,引发了一系列钙碱性的岩浆活动;早二叠世该带已进入陆相环境,但北天山洋残余洋盆的俯冲持续到中二叠世;晚二叠世全面进入陆内演化阶段,区域构造应力性质由挤压变为伸展。伴随洋-陆构造演化,形成了莱历斯高尔和阿希两大矿集区,分别对应2套成矿系统：与侵入岩浆活动有关的矽卡岩-斑岩-热液脉型铁、铜、钼、金、锑、铅、锌成矿系统和与次火山热液活动有关的浅成低温热液-斑岩型金、铅、锌、铜成矿系统。     

内蒙古赤峰市大营子花岗岩体多期次侵入的证据及其地质意义

大营子岩体位于内蒙古赤峰市西北部,多年来因发现碾子沟钼矿床而广受关注。通过研究发现,大营子花岗岩无论是野外空间产状、岩相特点及含矿性,还是岩石地球化学及同位素年代学特征,内部的黑云母二长花岗岩和边缘的正长花岗岩都存在明显的差异,显示了该岩体实际上是一个多期岩浆侵入的复合岩体。整体上大营子岩体岩石地球化学特征表现为高硅、富铝、富碱、低镁、贫钙的特点,富集大离子亲石元素(LILE)Rb、Th,亏损高场强元素(HFSE)Ti,亏损P元素。稀土元素组成总体含量较高,轻、重稀土分馏明显,Eu负异常显著。其中,边缘相正长花岗岩比中心相黑云母二长花岗岩具有更明显的Eu负异常和较低的微量元素U、Ba和Sr。边缘正长花岗岩锆石U-Pb同位素年龄为(267.6±2.8)Ma, 属于海西-早印支期华北克拉通北缘岩浆作用的产物,形成于造山晚期或后造山伸展作用诱发的下地壳部分熔融,为季家沟钼矿点(床)的赋矿围岩;中心相黑云母二长花岗岩具有(152.4±1.6)Ma的锆石U-Pb年龄,属于燕山期造山后陆内伸展或岩石圈大规模减薄环境岩浆作用的产物,为碾子沟钼矿床的赋矿围岩。     

电子商务影响下的“淘宝村”乡村重构多维度分析——以湖北省十堰市郧西县下营村为例

以湖北省十堰市郧西县下营村为例,利用半结构式访谈、问卷调查并结合遥感影像解译与GIS可视化表达等方法对电子商务驱动下乡村经济、社会及空间重构进行刻画。研究表明：① 下营村由传统的农业主导转变为一、二、三产业融合发展的多元结构,并显露出生态化转向。② 社会空间趋向于就业高度非农化、治理主体多元化、公共服务健全化、生活方式现代化及交往空间虚拟化。③ 农业生产空间逐步压缩,非农生产空间逐步扩张,生产-生态复合空间增加,居住空间呈现多功能化、集约化。④ 产业基础、电商平台、物流设施、乡村精英、资源禀赋和政府支持为其转型与发展提供了初始引擎、资源支撑和外部支持。     

Apparent resistivity of azimuthal anisotropy layered media

Introduction The method of apparent resistivity with direct current (DC) measurement, adopted from geophysical exploration, is one of the most important precursory approaches in earthquake prediction, in which the geo-electric constitutive model is illustrated by the scalar theory Archies law and correspondingly a set of calculation methods for apparent resistivity of layered media has been established (QIAN, et al, 1985; YAO, 1989). But this is not consistent with the fact that in earthqu…