高程误差对双星定位系统定位精度的影响研究

分析了两种获得高程的途径对定位精度的影响,推出其误差表达式。大量的仿真分析结果表明,在两种情况下,相同的数字地图高程误差与高度表误差对定位精度的影响完全相同,同时两种高程误差对定位精度影响的规律为:对东西向定位误差影响较小;而对南北向定位误差影响较大,纬度越低影响越大,纬度越高影响越小。     

路由器实现VPN连接及地震信息网络VPN应用分析

介绍了VPN技术和路由器实现VPN连接的建立过程。结合地震信息网络现状，分析了VPN技术应用前景，提出了基于VPN技术整合地震信息网络全国虚拟专网初步设想。     

Impact of land-use change on soil properties in a typical karst agricultural region of Southwest China: a case study of Xiaojiang watershed, Yunnan

Xiaojiang watershed is a typical karst agricultural region of Yunan Province, China. A case study of land-use changes documents changes of soil properties from 1982 to 2003. The results are as follows: (1) The total land use transformed covers 610.12 km², of which land use changed from unused land into cultivated land and forestland, and forestland into cultivated land during the past 20 years in Xiaojiang watershed. (2) The rapid growth of population and economic development were the main driving forces of cultivated land increase. (3) Soil properties showed modification owing to different land-use changes. The contents of the soil organic matter, total nitrogen, and total phosphorus in 2003 were significantly lower than that in 1982 after the forestland and unused land were transformed into the cultivated land, but the soil pH increased significantly in 2003. Organic matter, total nitrogen, and total phosphorus for shorter-time reforestation land declined, but the pH increased. Soil properties have improved significantly after cropland was transformed into orchard land. The organic matter, total nitrogen, total phosphorus, available nitrogen, and available phosphorus declined significantly, but pH increased significantly after rock desertification.     

GPS/DR组合系统的一种数据处理技术

根据GPS以及DR的采样频率的不同,引入量测预处理技术并用于GPS/DR的组合算法中,进而建立了采用量测预处理技术的卡尔曼滤波方程。最后通过实际的动态试验,论证了上述算法,并得出相应的结论。     

Filter Method and Its Consistency of Double-Star Position/SINS Integrated System

According to the characteristic of Beidou Double-star positing system (for short: Double-star position), the optimal predication model of Double-star position/SINS integrated system is put forward, which can make use of the delayed position in-formation from Double-star positioning system to predicate optimally for the integrated system, and then to correct SINS, and af-fords integrated results of some navigation parameters. In order to validate the consistency of the filter, the criteria for consistency of a filter is also studied, and the tested statistics are given, the experiment based on practical measured data shows that the filtering method is consistent with the integrated system.     

Uptake, accumulation and translocation of polycyclic aromatic hydrocarbons by winter wheat cultured on oily sludge-amended soil

The purpose of this study is to comparatively investigate the plant uptake, accumulation and translocation behaviors of polycyclic aromatic hydrocarbons (PAHs) as priority pollutants in soil contaminated with oily sludge. The influence of different oily sludge application doses on the uptake of contaminants was studied together with the profile of individual PAH in roots, straws and leaves of winter wheat. Pot experiments were conducted using oily sludge application doses of 0, 5, 10, 15 and 20 percent, respectively. The total PAHs contents of control soil and oily sludge were 16.96 and 3504.66 μg/g, respectively. Analysis for the contents of the 16 PAHs was carried out with a HPLC-UV using plant tissue samples obtained at the 265th day of growth. The total PAHs contents in treated winter wheat were 9.02-334.81 ng/g for roots, 8.45-336.52 ng/g for straws and 10.70-406.32 ng/g for leaves. In addition to 5% of oily sludge dose, the total PAHs content in leaves was always highest under other doses of oily sludge application. With respect to individual PAH, the content did not show a significant plant tissue related trend. However, both the total content and individual content of PAHs in treated winter wheat tissues did increase with increasing oily sludge application dose. Another analysis for the control soil indicates that the degradation rate of PAHs was significantly enhanced by winter wheat after 265 days of growth based on the residual concentrations of PAHs in planted and unplanted soils.     

细粒沉积物(岩)中重矿物提取方法的改进

随着近百年的重矿物研究,从沉积物中提取重矿物的实验方法已经形成了固定模式,然而这些传统方法都是对砂岩粗颗粒矿物研究经验的积累,并不适用于泥质含量高的细粒沉积物.根据溶胶稳定(DLVO)理论,悬浮于溶液中的微细颗粒会因分子间作用力的相互吸引絮凝成团,从而影响细粒沉积物中重矿物提取的效果.实验研究证明,影响重矿物提取的主要因素是微细矿物颗粒间的絮凝作用,而并非有机重液的黏度.如何克服微粒间的絮凝作用是提取泥岩和粉砂岩中重矿物的关键.实验对比分析表明,添加分散剂的超声波振动和自然沉降法可以在克服絮凝作用的前提下有效去除泥质成分,同时对粉砂级矿物进行精确的粒径分选;离心分离同样也可以克服微粒间的絮凝作用,在重液分离过程中使重矿物顺利从轻矿物中分离.以上3种方法的联合使用可以弥补传统的重矿物提取方法的不足,并显著提高泥岩、粉砂岩中重矿物的提取率.     

内蒙古中东部草原景观区多金属矿地球化学勘查方法对比研究

内蒙古中东部草原景观区成矿地质条件有利,但由于风成砂等的覆盖,导致常规地球化学勘查在该地区找矿中受到限制。在内蒙古东乌旗1017高地进行了土壤热磁组分测量、土壤细粒级组分测量和铁锰氧化物态测量方法的对比试验,结果表明,3种方法均能有效地圈出地球化学异常,而且3种方法圈定的异常吻合程度很好。相比较而言,土壤热磁组分测量能够显著提高异常强度,有利于发现微弱的地球化学异常信息,显示出该方法在草原景观区良好的应用前景。     

北京市大气可吸入颗粒物的化学成分和来源

2007年3月至2008年5月,在北京市成府路东口设立采样点,共采集监测周期为一周的PM2.5(直径小于2.5μm的大气可吸入颗粒物)样品56个,用HR-ICP-MS方法测量了15种元素的含量,并在此基础上应用主因子分析法对PM2.5中这些元素的来源进行探讨。同时,在2008年奥运会和残奥会期间开展了24h时间间隔的密集采样,特别分析了机动车限行期间细颗粒污染物的浓度特征。结果表明,2007年春季至2008年春季期间北京市大气PM2.5平均浓度为72.9μg/m3,超过美国环保局（USEPA）制定的PM2.5年平均浓度限值15μg/m3的近5倍。机动车限行期间北京成府路东口采样点大气PM2.5的平均浓度为40.7μg/m3。通过因子分析方法确定北京PM2.5的3种可能来源：①交通排放、工业排放和燃煤,特征元素为Cu、Zn、As、Sn、Sb、Cd、Pb;②本地扬尘和远源沙尘细颗粒;③可能与成土母岩风化有关的土壤颗粒的再悬浮和/或迁移,其方差贡献率分别为41.2%、31.4%和12.2%。