水体溶解氧检测方法

本文综述了水体溶解氧的各种检测方法及原理,重点讨论了一种新的光学检测方法--荧光淬灭法.该方法使用钌的络合物作为荧光敏感剂,在激发光的照射下发出荧光,该荧光可被分子氧有效地淬灭,其淬灭过程符合Stem-Volmer方程,通过检测荧光强度就可以推导出水中溶解氧的含量.     

基于数据仓库的WEBGIS研究

为适应1∶5万空间地理数据库应用的需要,作者提出了一种基于数据仓库的WEBGIS框架,分析了其中的关键技术并简述了在安徽资源与环境网络系统中的应用.     

Comparison of two topical treatments of gastro-oesophageal regurgitation in dogs during general anaesthesia

ObjectiveTo determine whether suction, lavage and instillation of sodium bicarbonate, following a gastro-oesophageal regurgitation event under general anaesthesia, would alter oesophageal pH to a greater degree than when lavage was not used.Study designProspective, randomised, clinical study.AnimalsA group of 22 client-owned dogs.MethodsDogs presenting with gastro-oesophageal regurgitation (GOReg) under general anaesthesia were randomised into groups: no lavage (G1) or lavage (G2). All dogs underwent oesophageal suctioning until no further regurgitant material was retrieved. Dogs in G2 had oesophageal lavage with tap water until the suctioned water was clear. All dogs then had 4.2% sodium bicarbonate (0.6 mL kg^–1) instilled into the oesophagus. An oesophageal pH probe was placed to record pH immediately after: GOReg (T1), suctioning (T2), lavage of the oesophagus (T3; G2 only) and sodium bicarbonate instillation (T4). Categorical data were analysed using Fisher’s exact test, and continuous data were analysed using either the two-sample t-test or the Wilcoxon rank-sum test. Parametric data are reported as mean ± standard deviation and non-parametric data as median (interquartile range). A p value < 0.05 was considered significant.ResultsOesophageal pH was low in both groups immediately after GOReg [G1: 2.95 (2.20–4.18), G2: 3.29 (1.41–4.03)] but oesophageal pH was not significantly different between groups at T1, T2 and T4. Oesophageal lavage significantly increased pH but the overall change in pH following bicarbonate administration (T2–T4) was not significantly different between groups [G1: 3.16 ± 1.52, G2: 3.52 ± 1.47]. No adverse events following GOReg were recorded.Conclusions and clinical relevance:Both groups had similar and clinically important increases in oesophageal pH. Although oesophageal lavage increased pH, this did not affect the final oesophageal pH when sodium bicarbonate was instilled and therefore may be an unnecessary step.     

Quantifying Pinyon-Juniper Reduction within North America's Sagebrush Ecosystem

One of the primary conservation threats surrounding sagebrush (Artemisia spp.) ecosystems in the Intermountain West of the United States is the expansion and infilling of pinyon pine (Pinus edulis, P. monophylla) and juniper (Juniperus spp.) woodlands. Woodland expansion into sagebrush ecosystems has demonstrated impacts on sagebrush-associated flora and fauna, particularly the greater sage-grouse (Centrocercus urophasianus). These impacts have prompted government agencies, land managers, and landowners to ramp up pinyon-juniper removal efforts to maintain and restore sagebrush ecosystems. Accurately quantifying and analyzing management activities over time across broad spatial extents still poses a major challenge. Such information is vital to broad-scale planning and coordination of management efforts. To address this problem and aid future management planning, we applied a remote sensing change detection approach to map reductions in pinyon-juniper cover across the sage-grouse range and developed a method for rapidly updating maps of canopy cover. We found total conifer reduction over the past several yr (2011−2013 to 2015−2017) amounted to 1.6% of the area supporting tree cover within our study area, which is likely just keeping pace with estimates of expansion. Two-thirds of conifer reduction was attributed to active management (1.04% of the treed area) while wildfire accounted for one-third of all estimated conifer reduction in the region (0.56% of the treed area). Our results also illustrate the breadth of this management effort—crossing ownership, agency, and state boundaries. We conclude by identifying some key priorities that should be considered in future conifer management efforts based on our comprehensive assessment.     

重庆市主城区建筑材料暴露存量及大气污染损失价值量核算

通过卫星遥感图片解译和实地调查的技术路线,对重庆市主城建成区室外建筑材料暴露存量进行了调查,同时核算了大气中SO2和酸雨两种污染因子对建筑材料造成的直接经济损失.结果表明,2004年,重庆市主城建成区建筑材料暴露总存量为18 546.9 m2,其中陶瓷暴露存量最大,占总暴露量的49.30%;大气污染对该区域建筑材料腐蚀的经济损失价值量为8 211.80万元,对铝的腐蚀造成的经济损失最大,占总损失值的50.1%.     

最佳特征影像组合综合选择指数的研究

最佳特征影像组合的选择是决定遥感影像信息提取与影像分类效果的关键环节之一。本文在分析多种定量选择方法的基础上，对不同方法的相关性及其存在的差异进行了深入的探讨，提出了综合选择指数法，经试验初步认为综合选择指数能较好地进行最佳特征影像组合的选择，并提出了构建综合选择指数模型的方法与原则。     

早稻三化螟生命表及其分析

本文应用昆虫生命表方法研究三化螟的发生量预测及其致量控制问题,试验在广东省海陵岛进行,当地的主要为害世代为第二世代,根据这个特点,以当代实际卵量与前一世代的顶期卵量的比率,即有效卵量概率,作为连续世代的连接点,组建自越冬幼虫至第二世代的连续生命表,应用排除作用控制指致评价重要因子和分析关健因子的作用,试验结果说明,越冬后幼虫至蛹的死亡,特别是第一世代有效卵量概率对第二世代数量的影响甚大;第一世代幼虫侵入后至第二世代期间,自然种群的发展过程比较稳定,根据第一世代卵量估计第二世代的数量有可能获得较好的顶测结果。     

陕北农牧交错带土地荒漠化动态变化研究

应用遥感技术与GIS相结合的方法,对陕北农牧交错带不同时期的遥感影像进行校正、增强和自动分类识别,得到1986,1993和2000年3个时期土地荒漠化分布图(数字地图)、空间数据库及其面积统计。结果表明,近15年来该地区土地荒漠化面积增加,严重荒漠化土地大幅度减少,中度和轻度荒漠化土地增多;荒漠化土地的时空转换频繁且复杂,耕地沙化和林地退化是土地荒漠化的主要来源,基本农田建设和生态自然恢复使荒漠化土地发生逆转,区域土地荒漠化得到有效控制,但土地生态系统还相当脆弱;其中人畜数量增加、社会经济发展是驱动荒漠化的主要因子。     

一种基于人工免疫系统的学习算法研究

通过对人工免疫系统初始形成和后续发展过程的分析,提出了一种可用于分类的学习算法,在算法中将免疫系统的各个要素和学习过程相结合,详细说明了算法的过程,并且通过实验数据验证了算法的有效性。     

基于GIS的森林火灾自动定位系统设计与开发

根据森林防火管理的实际需求,以嘹望塔视频监控设备为硬件基础,提出了双点定位方法与单点定位方法相结合的综合方案,综合运用组件GIS、ArcSDE数据库引擎、.NET等多种先进软件技术设计开发了鹫峰国家森林公园森林火灾定位系统,解决了目前森林防火基层管理亟待解决的着火点现场定位问题.