Environmental factors of road slope stability in mountain area using principal component analysis and hierarchy cluster

Nine environmental factors of 147 roadside soil samples were administered in Sichuan Basin of China and principal component analysis was conducted using the Pearson correlation matrix. The results show that the first four principal components whose eigenvalue is over 1.00 can be extracted. The first principal component which is consisted of rock type, soil type, weathering degree, and soil depth is the most important factor of all. The geographical position which is consisted of altitude, longitude, and latitude is included in the second and the third principal components. The fourth principal component shows that the terrain factor influences the rock slope stability. The hierarchy cluster shows that rock type and soil type play the maximum positive correlation, while the slope and the aspect present the maximum negative correlation.     

OSL dating of a Holocene loess-paleosol sequence in the southern Loess Plateau,China

Optically stimulated luminescence (OSL) dating of polymineral fine-grained loess samples collected from the southern Loess Plateau of China was conducted using the single-aliquot regenerative-dose (SAR) protocol. A ‘Double-SAR’ procedure in which aliquots are subjected to both infrared (IR) and blue stimulations was used, and two sets of equivalent dose (D _e ) determinations were produced. These doses are assumed to be predominantly related to the feldspathic and quartz fine grain populations, respectively. The results revealed that the OSL ages estimated by infrared stimulated luminescence (IRSL) signals and those estimated by [post-IR] stimulated luminescence ([post-IR] OSL) signals disagreed. Specifically, the ages estimated using the IRSL signals were smaller than those estimated using [post-IR] OSL signals. The results of an anomalous fading test of the two types of OSL signals revealed that the [post-IR] OSL signals from the etched sub-sample (by H₂SiF₆ and HF) and the un-etched sub-sample did not fade significantly. However, the IRSL signals from the un-etched sub-sample showed obvious signs of fading. These findings indicate that the lower age estimated by IRSL is due to the anomalous fading of feldspar IR signals in the polymineral fine grains. For samples collected from greater than 100 cm, the estimates of their OSL ages using two types of luminescence signals generally agreed with their pre-estimated ages, especially those of the [post-IR] OSL signals. However, for the three samples that were collected from a depth of less than 100 cm, their OSL ages were remarkably underestimated, possibly due to the enhanced human activity (such as soil cultivation) that has occurred in the region since 3000 a B.P.     

舟山海域外来物种地中海贻贝的自然分布现状及生态影响

以筛选的2个可鉴别的地中海贻贝（Mytilus galloprovincialis）、厚壳贻贝（M.coruscus）及其杂交后代的PCR标记（扩增核基因Glu-5’特异片段PCR标记Me14/Me17和延伸因子1α第一个内含子区段PCR标记引物EFbisF/EFbisR）,对舟山海域3个贻贝主产区（马鞍列岛海域、浪岗山列岛海域、中街山列岛海域）采集的贻贝样本的种类进行鉴别.研究结果显示：100个马鞍列岛海域贻贝个体和30个中街山列岛海域贻贝个体均为厚壳贻贝;而54个浪岗山列岛海域贻贝样本中,16个个体（29.6%）为厚壳贻贝,38个个体（70.4%）为地中海贻贝;3个群体中均未检测到2种贻贝的杂交个体.因此,推测舟山海域地中海贻贝自然分布仅局限于局部海区,但在适宜的海区地中海贻贝可取代厚壳贻贝成为贻贝床的优势物种,舟山海域贻贝床的动态变化值得进一步关注;贻贝样本中没有检测到地中海贻贝与厚壳贻贝的杂交个体,表明调查海域可能没有杂交贻贝分布或数量极少,地中海贻贝通过杂交、基因渐渗污染厚壳贻贝基因组的风险较小.     

基于DEM三维地层建模及一体化显示

目前三维地层表面建模方法构建的三维地层模型上表面粗糙,与地形不一致.在分析当前建模方法缺陷的基础上,基于多层DEM建模思想,提出了利用DEM修正主TIN的建模方法;该方法可保证模型与地形的空间一致性,实现模型与地理数据的一体化显示.并提出了利用虚拟钻孔进行剖面图离散化处理,将建模数据源统一为钻孔数据,从而将剖面图融入实际建模流程,解决了单一钻孔数据导致建模结果不精确及模型无法修正的问题,也简化了多源数据导致建模方法复杂的问题.最后以合肥市某区为例,展示了该方法的实现过程及建模效果.     

丽江地区人居环境的GIS空间分析

应用地理信息系统(GIS)的空间分析功能对云南省丽江地区的地势变化、坡度、坡向以及居民点分布与地形的关系等基本问题进行了定量分析,为丽江地区人居环境的深入研究提供了分析的依据;同时,探讨了应用GIS空间分析功能研究人居环境的一般过程和方法流程.     

云南金线鲃属鱼类一新种记述

描记采于曲靖市郊一地下水出水口金线鱼巴属一新种 ,命名为曲靖金线鱼巴Sinocyclocheilusqujingen sis,sp.nov.。新种口须特长 ,与长须金线鱼巴S .longibarbatusWang(1 989)相近 ,但体鳞细小 ,隐于皮下 ,头长等于体高 ,两种间分子遗传距离 1 3 6% ,表明为亲缘较远的两个独立种     

A Method for Determining Precisely the Barycentric Position of Uranus Observed with CCD Systems

A method for determining precisely the barycentric position of Uranus by CCD systems is presented in this present article. It is required according to the method that the CCD observations obtained both with a long-focus telescope which is used to observe the major satellites of Uranus and with a meridian circle which works in a CCD drift scanning manner when it is used to observe some faint stars. The key part of the method is tested by the observations obtained with the 1-meter telescope at the Yunnan Observatory. This revised version was published online in July 2006 with corrections to the Cover Date.     

低纬子午环配备科学CCD的初步方案

根据低纬子午环配备科学ＣＣＤ后仍然能对天体位置作绝对测定的要求，提出了该仪器配备科学ＣＣＤ的初步方案，包括在子午方向和卯酉方向观测时，ＣＣＤ芯片如何跟踪星像，如何将芯片致冷，提高信噪比，既能保持镜筒的平衡，又不破坏观测室内空气的稳定性，如何更准确地测定光轴指向的变化。文中还对一次观测的天区面积作了估计。     

西安灞河左库滑坡发育的阶段性及形成主因的历史转化

根据西安灞河左岸滑坡的基本特点、空间展布规律以及与后期沉积物之间的接触关系，本文分析论证了该区滑坡发育的阶段性特征及各阶段滑坡形成的主要原因与营力因素的历史转化性问题。     

空间时代地面光学天体测量的意义

从基本天体测量的主要任务出发，介绍了绝对测定和相对测量之间的区别和不同用途，并针对河外射电源参考架和依巴谷参考架的高精度的不足之处，说明了地面光学天体测量的长期性和灵活性等优势正是克服这些不足之处所必须的，但这不应是传统的已有精度下的地面光学天体测量，而应是与空间测量精度可比的要求下的地面测量，两者配合起来，将能促进本学科和相关学科的发展。