芙蓉锡矿田骑田岭花岗岩黑云母矿物化学组成及其对锡成矿的指示意义

芙蓉锡矿田骑田岭复式岩体主要由早阶段角闪石黑云母花岗岩和晚阶段黑云母花岗岩组成.电子探针分析结果表明角闪石黑云母花岗岩中的黑云母属于铁黑云母,黑云母花岗岩中的黑云母属于铁叶云母.相对于黑云母花岗岩,角闪石黑云母花岗岩中黑云母的MgO、TiO2含量偏高,Al2O3含量偏低.矿物化学研究结果显示,角闪石黑云母花岗岩中黑云母的结晶温度、氧逸度(logfO2)分别为680℃～740℃、-16.00～-15.31,黑云母花岗岩中黑云母的结晶温度、氧逸度分别为530℃～650℃、-19.20～-17.50.从角闪石黑云母花岗岩到黑云母花岗岩,岩浆结晶温度和氧逸度逐渐降低.与花岗岩有关的共存流体性质的研究发现,与角闪石黑云母花岗岩共存的热液流体log(fH2O/fHF)fluid,log(fH2O/fHCl)fluid,log(fHF/fHCl)fiuid值分别为4.22～4.39,2.78～3.24,-1.82～-1.73,而与黑云母花岗岩共存的热液流体log(fH2O/fHF)fluid,log(fH2OfHCl)fluid,log(fHF/fHCl)fluid值分别为3.27～3.53,2.85～3.22,-0.75～-0.22,可见与两种岩石类型共存热液流体的性质存在明显差异,且热液中Cl、Sn含量变化与岩浆结晶分异指数呈正相关关系.骑田岭岩体从角闪石黑云母花岗岩到黑云母花岗岩,随着岩浆的演化.岩浆结晶期后分异出的热液流体向富Cl和Sn方向演化.芙蓉锡矿田的成矿流体应主要来源于黑云母花岗岩岩浆结晶期后分异出的岩浆热液.     

城市公共饮用水应急水源勘查及其意义——以浙江长兴雉城镇应急水源勘查为例

通过浙江长兴雉城镇公共饮用水应急水源勘查实例,认为充分利用原有地下水供水井,并在地下水资源较为丰富、人口较为集中的社区选择施工供水深井作为公共饮用水应急水源是科学的、经济的、可行的.作为公益性市政基础建设,政府有责任落实到位,以尽快建立城市公共饮用水危机应急供水预案并采取措施.     

北京市地面沉降发展及对城市建设的影响

地面沉降是北京市平原区主要地质灾害之一,最早在1935年发现于西单至东单一带,到目前为止已经形成了多个地面沉降中心,到2005年底,累计沉降量大于50mm的沉降区达4114 km~2,大于100mm的沉降区达2815km~2。地面沉降已经对城市基础设施造成一定程度的破坏,并且已经对奥运场馆、规划新城、CBD等重要区域构成潜在威胁,所以必须及时制定完善的防治措施来降低地面沉降的危害。     

Cold Air Activities in July 2004 and Its Impact on Intense Rainfalls over Southwest China

The severe rainfall events in the mid-summer of July 2004 and the roles of cold air in the forma- tion of heavy precipitation are investigated by using daily observational precipitation data of China and NCEP/NCAR reanalysis.The results show that the severe rainfalls in Southwest China are closely related to the cold air activities from the mid-high latitudes,and the events take place under the cooperative effects of mid-high latitude circulation and low latitude synoptic regimes.It is the merging of a cold vortex over mid-latitudes with the northward landing typhoon and eastward Southwest China Vortex,as well as the abrupt transformation from a transversal trough into an upright one that causes three large alterations of mid-high atmospheric circulation respectively in the early and middle ten days of this month.Then,the amplitude of long waves soon magnifies,leading to the unusual intrusion of cold air to low-latitude areas in the mid-summer.Meanwhile,the warm and humid southwest summer monsoon is quite active.The strong interactions of cold air and summer monsoon over Southwest China result in the large-scale convective rain- falls on the southern side of cold air. With regard to the activities of cold air,it can influence rainfalls in three prominent ways.Firstly,the incursion of upper-level cold air is often accompanied by partial southerly upper-level jet.The ascending branch of the corresponding secondary circulation,which is on the left front side of the jet center,provides the favorite dynamic upward motion for the rainfalls.Secondly,the southward movement of cold air contributes to the establishment of atmospheric baroclinic structure,which would lead to baroclinic disturbances.The atmospheric disturbances associated with the intrusion of cold air can destroy the potential instability strat- ification,release the convective available potential energy(CAPE)and finally cause convective activities.In addition,the advection processes of dry and cold air at the upper level along with the advection of humid and warm air at the lower level are rather significant for the reestablishment of potential instability in the precipitation area,which is one of the crucial factors contributing to persistent rainfalls.     

Automatic Extraction of Power Lines From Aerial Images

There has been little investigation for the automatic extraction of power lines from aerial images due to the low resolution of aerial images in the past decades. With increasing aerial photogrammetric technology and sensor technology, it is possible for photogrammetrists to monitor the status of power lines. This letter analyzes the property of imaged power lines and presents an algorithm to automatically extract the power line from aerial images acquired by an aerial digital camera onboard a helicopter. This algorithm first uses a Radon transform to extract line segments of the power line, then uses the grouping method to link each segment, and finally applies the Kalman filter technology to connect the segments into an entire line. We compared our algorithm with the line mask detector method and the ratio line detector, and evaluated their performances. The experimental results demonstrated that our algorithm can successfully extract the power lines from aerial images regardless of background complexity. This presented method has successfully been applied in China National 863 project for power line surveillance, 3-D reconstruction, and modeling.     

Road Surface Modeling and Representation from Point Cloud Based on Fuzzy Clustering

A scheme for an automatic road surface modeling from a noisy point cloud is presented. The normal vectors of the point cloud are estimated by distance-weighted fitting of local plane. Then, an automati...     

对地观测卫星地面站的站址选择和布局分析

现代小卫星技术是近些年来迅速发展起来的航天领域高新技术，利用该技术为地球观测服务是一件远景可观、意义深远的事情。在对地观测卫星的诸多关键技术之中，地面站的设计是一个很重要的方面。本文主要对对地观测卫星地面站的站址选择与布局进行了详细的讨论。     

基于纠错编码的小波域自适应盲水印算法

提出了一种小波域自适应盲水印算法,并采用(7,4)汉明码技术进行纠错编码。以伪随机二值序列作为水印,采用中值系数抖动的方法将水印嵌入到小波变换后的低频分量,并且根据小波域系数间隔的大小自适应地确定水印量化步长,水印检测过程不需要原始图像的参与。实验结果表明,算法的自适应性强,具有较好的不可见性,且可以有效地抵抗JPEG压缩、锐化、加噪、模糊和缩放等攻击。     

临安大气气溶胶理化特性季节变化

分别利用碳成分分析仪、离子色谱仪和原子吸收光谱仪等获取浙江省临安地区大气气溶胶在春、夏、秋、冬四季的质量浓度、离子与碳成分特性，并对不同粒径气溶胶成分分布特点作了较详细分析。结果表明:气溶胶质量浓度、可溶性离子浓度以及碳成分浓度具有明显的季节变化趋势。整个尺度范围内，气溶胶质量浓度季节变化特点为春季浓度最高，达到534 μg/m3；冬季次之，质量浓度为117.21 μg/m3；夏季浓度最低，平均为65.7 μg/m3；秋季质量浓度98.6 μg/m3。可溶性离子成分在气溶胶中所占比例具有明显的季节性，其中夏季最高为49.4%，春季最低为11.3%。硫酸根离子SO₄2-和氨根离子NH₄+和硝酸根离子NO₃- 3种离子浓度之和约占离子总量的75%~83%。受温度影响，硝酸根离子NO₃-浓度随季节变化幅度较大，夏季平均浓度为1.7 μg/m3, 冬季平均浓度为11.5 μg/m3，是夏季浓度的6.8倍。碳浓度分布特点显示，气溶胶中元素碳浓度春季最高，夏季最低。有机碳浓度春季最高，冬季最低。气溶胶粒度分布特点也非常明显。四季中粒径小于11 μm（PM₁₁）的气溶胶均占气溶胶总量的90%以上，粒径小于2.1 μm（PM_2.1）的气溶胶占到气溶胶总量的53%以上。可溶性离子在粒径小于2.1 μm气溶胶颗粒中，以硫酸根离子、氨根离子和硝酸根离子为主。碳成分尺度分布特征为颗粒越小，有机碳及元素碳浓度越高。     

基于Visual C++程序设计语言的地面气候旬月报的报文译制

从地面气候旬月报的收集开始,进行报文的合并、检索、翻译。检索出需要的区站号信息,以便减轻翻译过程的工作量,提高系统运行速度。翻译过程分为2部分:旬报翻译和月报翻译。每旬第一天进行旬报翻译,每月第一天进行月报翻译。翻译结果以文本形式显示。