海量点云数据等高线生成算法研究

针对大范围高精度的等高线快速生成问题,提出一种基于三维激光扫描海量点云数据快速生成等高线的新方法。该方法将流处理算法引入到海量点云数据处理中,基于流处理算法的三角剖分、三角网模型平滑及等高线提取等关键技术完成等高线快速生成。结果表明,基于流处理的算法不仅突破了点云数据量和范围的限制,而且能够高效地生成高质量的等高线以满足地形测量要求。     

清代耕地数据恢复重建方法与实证研究

本文尝试构建一套适用于清代耕地数据的修正校验体系,以清代官方册载田亩数据为基础,采用人口基数和垦殖趋势进行检验和订正,通过替换、引用、衔接对比等方法进行数据修正,重建清代耕地数据,以期为后续相关研究提供参考.在建立理论分析框架的基础上,本文以历史资料相对丰富的山东省为例,对清代山东省的耕地数据进行修正与校验,结果表明：① 清代山东省的册载田亩数据不实情况普遍,经要素法修正的数据虽然通过了人口检验,但未能通过垦殖趋势校验,有必要进行进一步的订正和校准;② 在修正和校验过程中应综合考虑不同省份间垦殖政策、种植制度、自然条件等的差异,从修正系数到校验重点进行因时因地调整;③ 清前期山东省耕地增长主要受限于劳动力供给,耕地面积接近于劳动力供给线,随着人口的增长,耕地面积逐渐趋向于温饱线.同治以后,耕地面积开始低于温饱线,需要依靠粮食输入才能满足人口需求,山东省由粮食输出省变为粮食输入省.     

Reconstructing the historical spatial land use pattern for Jiangsu Province in mid-Qing Dynasty

This study is proposed to reconstruct a high-resolution spatial distribution of historical land use pattern with all land use types to overcome low-accuracy and/or the monotonic land use type in current historical land use reconstruction studies. The year of 1820 is set as the temporal section and the administrative area of Jiangsu Province is the study area. Land use types being reconstructed include farmland, residential land (including both urban land and rural residential land), water body, and other land (including forest land, grassland, and unused land). Data sources mainly refer to historical documents, historical geographic research outcomes, contemporary statistics, and natural environmental data. With great considerations over regional natural resources and social and economic conditions, a few theoretical assumptions have been proposed to facilitate the adjustment on prefecture farmland, urban land, and rural residential land. Upholding the idea that the contemporary land use pattern has been inherently in sequence with the historical land use pattern as well as the land use pattern shall be consistent to its accessibility, this study reconstructs the land use pattern in Jiangsu Province in 1820 with 100 m*100 m grids based on accessibility analysis and comprehensive evaluation. The outcome has been tested as valid by regionalization and correlation analysis. The resulted spatial distribution shows that back in 1820 in Jiangsu Province: (1) farmland, urban land, rural residential land, water body, and other land take about 48.49%, 4.46%, 0.16%, 15.03%, and 31.86% of the total land area respectively; (2) the land use pattern features high proportion of land in farming while low-proportion land in non-farming uses while population, topography, and the density of water body lead to great spatial variations; and (3) the reconstruction methodology has been tested as reasonable based on significant positive correlations between 1820 data and 1985 for both farmland and rural residential land at the prefecture level.     

不同激发环境下井中气枪震源特征研究

基于单枪容量为250in3的BHS-2200LL井中气枪,在内径0.2、5.0m不同激发井中开展了气枪震源特征对比分析,研究表明：①5.0m井中气枪激发产生的信号优势频率集中在10～40Hz,比在0.2m井中的低,这主要是由于较大水体利于气泡的震荡;②在能量方面,5.0m井中激发信号的能量强于0.2m井中的,幅度上相差1个数量级,单次激发的传播距离可达9km;③2种激发环境下产生的气枪信号都具有较好的重复性。     

浓海水冷冻脱盐技术研究

通过实验室冷冻离心实验,研究了浓海水的冷冻脱盐技术.实验研究了离心转速对冰冻的浓海水的脱盐和脱除钙镁离子的影响,并对多步冷冻脱盐前后余冰和浓海水的盐度分别进行分析,以及利用ICP-MS对其主要离子含鼍进行测定.实验结果表明,离心转速变化对冰冻浓海水脱盐、脱除钙镁离了的影响显著.各实验离心转速条件下,脱盐和脱除钙镁离了均有较好效果.脱除率均达到88.5%和87.4%以上.随着离心转速的提高,脱盐率提高,转速4 000 r/min达到最大,但是其变化幅度减小,进一步提高转速对脱盐率和钙镁离子脱除率的提高影响不大.经过多步冷冻脱盐发现,一次冷冻离心分离,得到的余冰的盐度脱除达到99.0%.通过与原浓海水离子含量相比,钾钙钠镁等主要离子含量降低为原浓海水的3%以下.而多步离心分离之后,得到的浓海水的盐度达到原浓海水的3.3倍.每步实验,均有低盐度,低离子含量的冰生成,冰的产最达到被处理的浓海水总体积的2/3以上.     

Biosorption and desorption of Cd^2＋ from wastewater by dehydrated shreds of Cladophorafascicularis

The adsorption and desorption of algae Cladophora fascicularis and their relation with initial Cd^2＋ concentration, initial pH, and co-existing ions were studied. Adsorption equilibrium and biosorption kinetics were established from batch experiments. The adsorption equilibrium was adequately described by the Langmuir isotherm, and biosorption kinetics was in pseudo-second order model. The experiment on co-existing ions showed that the biosorption capacity of biomass decreased with an increasing concentration of competing ions. Desorption experiments indicated that EDTA was efficient desorbent for recovery from Cd^2＋. With high capacities of metal biosorption and desorption, the biomass of Cladophora fascicularis is promising as a cost-effective biosorbent for the removal of Cd^2＋ from wastewater.     

基于Landsat 8遥感数据的东洞庭湖湿地变化监测与分析

基于2013~2018年Landsat8-OLI 9个时相的遥感数据,采用湿地三类分级系统,以决策树分类法提取不同时间的湿地类型,结果表明:2013-2018年东洞庭湖湖泊草洲、泥滩地和水域面积呈现动态变化,其中草洲面积平均714km²、泥滩地面积平均81km²、水域面积平均502km²;湖区草洲和水体面积占比大,且此消彼长,草洲面积平均占比55.1%,水域面积平均占比38.7%,泥滩地面积最少平均占比仅6.2%;水位变化是湖区草洲出露面积的主控因素,随水位升高,草洲出露面积逐渐减小,且在典型高低水位下草洲空间分布差异明显,高水位下主要分布在南部柴下洲和北部藕池河一带地形较高区域,而低水位条件下湖区大部分草洲面积分布广泛,其面积占湖区总面积的74%。成果进一步验证了东洞庭湖不同水情下的湿地景观格局。     

四川省雷电监测预警预报系统及其应用研究

四川省防雷中心利用闪电资料建立了雷电监测业务系统;采用决策树法, 结合T213模式资料和地面探空资料建立了雷电预报业务系统;采用配料法, 结合雷达资料和闪电定位资料建立了雷电短时临近预警系统, 2008年中心引入CAMS_LN-WS系统, 结合原有预警产品生成适合四川省的雷电短临预警产品。经过5年的效果验证, 四川省雷电监测预警预报系统准确率达到85%, 系统产品对政府组织防灾减灾工作所提供的支撑有效降低雷电灾害所造成的损失, 带来了很大的社会效益和经济效益。      

中国城市地价水平及变化影响因素分析

城市地价的影响因素众多且复杂,地价水平和地价变化趋势受到社会、经济、政策等多方面因素的共同影响。论文从城市土地供需和宏观政策角度选取房地产投资额、市辖区建设用地面积、耕地占用税等10 项影响因素,采用2008-2010 年全国105 个土地市场较发育城市分季度地价数据,建立地价水平值与地价增长率影响因素的多层线性模型,定量分析了不同行政层次下,各影响因素对城市土地价格和地价增长率的影响程度。研究结论显示,地价水平值与地价增长率的影响因素不尽相同,且主导因素差异显著：在市级地价影响因素中,房地产投资增长是地价上升的直接动力,而地价增长率则主要受城市建设用地面积、房地产投资额的影响较;省级耕地保护政策对平抑地价、控制地价涨速作用显著,其中新增建设用地土地有偿使用费和耕地占用税是省级层次影响最显著的两项政策指标。     

山地边界层急流的观测特性及其成因分析

分析浙江上虞丘陵山区边界层风、温实测资料 ,发现在高压形势下 ,该地边界层急流具有频发性和显著特征。分析表明 ,丘陵山区地形热力差异导致的气层斜压性 ,起因于湍流强度日变化的惯性振荡 ,以及湍流交换引起的动量下传 ,是该地边界层急流产生的重要机制 ;而丘陵山区特有的空悬逆温的发生发展 ,则是急流得以持续的关键因素