基于土地适宜性评价与元胞自动机模型的城市开发边界划定方法     

李焰  梁美丽 《北京测绘》2021,35(2):222-229

城市开发边界的划定可以在一定程度上引导城市空间的良性扩张。为了研究边界划定的方法,以我国某港口城市作为研究区域,在空间增长模拟的方向进行探索。研究中借助土地适宜性评价和元胞自动机边界工具,构建既符合生态资源环境要求又符合城市发展需要的边界划定,同时,为了实现城市用地健康和动态管控举措,提出了建立健全土地用地管理机制的要求。  相似文献   

移动背景下测量学AR实训教材设计     

夏慧琼  樊丽芳  林丽群  余辉亮 《北京测绘》2021,35(5):695-698

针对传统测量实践教学过程中对于来源多样、格式迥异的学习资料未能有效进行组织的问题,提出了增强现实(Augmented Reality,AR)实训教材的设计思路.结合测量实践课程的特点和AR技术优势,针对学生的情感认知及书籍的信息负荷等方面,从课程内容的布局、虚实场景的结合及交互方式等几个方面对AR实训教材进行设计.实现了纸质教材与移动端课程内容的融合与实时交互,为移动背景下的数字资源与传统书籍的有机结合提供一种借鉴方法.  相似文献   

Sulfur Isotope Fractionation in Magmatic Systems：Models of Rayleigh Distillation and Selective Flux   总被引：2，自引：0，他引：2  

郑永飞 《中国地球化学学报》1990,9(1):27-45

The effect of Rayleigh distillation by outgassing of SO2 and H2S on the isotopic composition of sulfur remaining in silicate melts is quantitatively modelled.A threshold mole fraction of sulfur in sulfide component of the melts is reckoned to be of critical importance in shifting the δ^34S of the melts mith respect to the original magmas.The partial equilibrium fractionation in a magmatic system is evaluated by assuming that a non-equilibrium flux of sulfur occurs between magmatic volatiles and the melts,while an equilibrium fractionation is approached between sulfate and sulfide within the melts.The results show that under high fo2 conditions,the sulfate/sulfide ratio in a melt entds to increase,and the δ^34S value of sulfur in a solidified rock might then be shifted in the positive direction.This may either be due to Rayleigh outgassing in case the mole fraction of sulfide is less than the threshold,or due to a unidirectional increase in δ^34S value of the sulfate with decreaing temperature,Conversely,at low fo2,the sulfate/sulfide ratio tends to decrease and the δ^34S value of total sulfur could be driven in the negative direction,either because of the Rayleigh outgassing in case the mole fraction of sulfide is greater than the threshold,or because of a unidirectional decrease inδ^34S value of the sulfide.To establish isotopic equilibrium between sulfate and sulfide,the HM,QFM or WM buffers in the magmatic system are suggested to provide the redox couple that could simultaneously reduce the sulfate and oxidize the sulfide.CaO present in the silicatte Melts is also called upon to participate in the chemical equilibrium between sulfate and sulfide,Consequently,the δ^34S value of an igneous rock could considerably deviate from that of its original magma due to the influence of oxygen fugacity and temperature at the time of magma solidification.  相似文献   

预测陕西关中地区需水量的改进GM(1,1)模型   总被引：6，自引：0，他引：6  

王菊翠  曹明明  仵彦卿 《干旱区地理》2006,29(1):35-41

需水量评价与预测是水资源规划与管理一项重要的研究内容。本文采用定额法计算需水量。通过对陕西关中地区需水量要素组成的分析,认为需水量要素属平稳时间序列,且一阶累加生成数据系列满足指数规律,符合灰色预测条件。为了提高GM(1,1)模型的精度,采用一种改变背景值的新方法,即:中心逼近方法。通过精度检验,中心逼近式GM(1,1)模型平均误差百分比、误差平方和分别比传统的GM(1,1)模型提高了0.147和1.579。用中心逼近式GM(1,1)模型预测需水量各要素近期和中长期值,经检验,其中非农业人口、农业人口、耕地面积、工业总产值预测模型满足一级模型,等级为良好。牲畜头数预测模型为不合格模型,分析其原因,主要是因为时间序列数据不完全符合指数规律。通过定额法计算,预计75%保证率时2005年和2010年关中地区工农业需水量分别占总需水量的92.21%和89.75%,生活需水量分别占7%和9.04%。  相似文献   

Temporal and dimensional distribution of sulfate-reducing bacteria （SRB） groups and quantity in the sediments of Lake Erhai     

Mingyi WANG Xiaobing LIANG Yaping ZHENG Youzhi ZHAO Zhongqing WEI 《中国地球化学学报》2006,25(B08):65-66

The purpose of the thesis is to analyze the temporal and dimensional distribution of sulfate-reducing bacteria （SRB） groups and quantity in Lake Erhai. In April and September 2005, two sediment cores were collected from Lake Erhai. SRB groups were analyzed by PCR with six-groups primers designed according to the specific 16SrDNA sequence. FISH （fluorescence in-situ hybridization） was established with the oligonucleotide probe （SRB385） and utilized to analyze SRB quantity in the sediments. The results showed that in the sediments of Lake Erhai four SRB groups were detected except Desulfobacterium and Desulfobacter, meanwhile Desulfovibrio-Desulfomicrobium were detected only in autumn; different SRB groups had different temporal and dimensional distribution, and each group in autumn is distributed more widely than in spring; FISH used to count SRB in the sediments of fresh lake was set up successfully; the analysis of correlation between the sediment＇s depth and SRB quantity had statistical meaning （P〈0.05） . The result showed that SRB quantity showed a decreasing trend with increasing depth. Through the analysis of randomized block designed analysis of variance, the difference in SRB quantity between spring and autumn also had statistical meaning （P〈0.001）, which revealed SRB quantity in autumn was larger than in spring; the result of FISH showed that there were some SRB in the deeper sediments in which no above-mentioned six SRB groups were detected by PCR. SRB groups in the sediments of Lake Erhai were rich, and the quantities of SRB groups in autumn were larger than in spring; possibly there were uncultivable SRB groups in the sediments of Lake Erhai.  相似文献   

Synergistic effect of combining sulfate reducing bacteria and zerovalent iron permeable reactive barriers on the treatment of groundwater rich in uranium, sulfate and heavy metals     

Zhengji YI Kaixuan TAN Zhenxun YU Aili TAN Shiqiang WANG 《中国地球化学学报》2006,25(B08):125-126

Uranium processing and mining activities that generate many contaminants, such as high concentrations of U （VI）, sulfate and heavy metals （Zn, Cu, Ni, etc）, may pose a serious threat to the groundwater resources. In recent years, considerable research has been conducted respectively on two kinds of permeable reactive barriers （PRB）, including zerovalent iron （ZVI） and sulfate reducing bacteria （SRB）, for in-situ removal of these pollutants from groundwater. However, little investigation has been carried out on the potential benefits of bioaugmenting ZVI barriers to enhance the elimination of the pollutants by combining ZVI with SRB systems. The main goal of this study was to conduct batch and column experiments to determine whether the combination of SRB and ZVI can function synergistically and accelerate the rate of pollutant removal. The results of anaerobic batch experiments demonstrated that although the integrated ZVI/PRB system itself has no ability to reduce and remove sulfate directly, SRB can utilize hydrogen gas produced during the slow process of ZVI corrosion as an electron donor to raise biomass yields significantly and accelerate reductive sulfate removal. In particular, ferrous cations produced as the byproduct of ZVI corrosion process reacted with hydrogen sulfide from sulfate reduction and formed iron-bearing sulfide precipitates, which can stimulate the growth of SRB and promote sulfate removal activity by eliminating the biotoxicity of hydrogen sulfide. It was also shown that secondary mineral products （pyrite/ferrous sulfide） formed as a consequence of microbial sulfate reduction and ZVI corrosion process can enhance the microbial precipitation of soluble U （VI） as insoluble uraninite（uranium dioxide）.  相似文献   

Speciation of sulfate components in size-fractionated aerosol particles using sulfur K-edge X-ray absorption near-edge structure （XANES）     

Yoshio Takahashi Yutaka Kanai Hikari Kamioka Atsuyuki Ohta Takuro Miyoshi Hiroshi Shimizu 《中国地球化学学报》2006,25(B08):222-222

Sulfates are a main constituent of aerosols, which sulfate aerosols, it is necessary to determine what can cause various environmental problems sulfate ions are contained in these aerosols In the evaluation of the influence of In this study, sulfur K-edge XANES was used to determine sulfate species present in size-fractionated aerosol particles based on the post-edge structure after the main absorption peak in the XANES region. Aerosol samples were collected as part of the Japan-China joint project, ＂Asian Dust Experiment on Climate Impact＂ using a low-volume Andersen-type air sampler. XANES was measured at Beamline BL-9A at Photon Factory, Japan. A comparison of the XANES spectra of reference sulfate materials and aerosol samples collected in Tsukuba in Japan clearly showed that （NH4）2SO4 was the main sulfur species in particles with a smaller diameter and gypsum was the main sulfur species in particles with a larger diameter. A simulation of the XANES spectra by reference materials allows us to obtain the quantitative mixing ratios of the different sulfate species present in the aerosol samples. The presence of minor sulfur species other than （NH4）2SO4 and gypsum at the surface of mineral aerosols is suggested in our simulations and by a surface-sensitive conversion electron/He-ion yield XANES. In the absence of a contribution from a large dust event, the mole concentration of gypsum in the mineral aerosol fraction determined by XANES is similar to that of Ca which is determined independently using ion chromatography. This shows that the Ca and sulfate in the mineral aerosols are present only as gypsum. Considering that calcite is the main Ca mineral in the original material arising from an arid and semi-arid area in China, it is strongly suggested that gypsum is formed in aerosol during its long-range transportation by a reaction between calcite and sulfate ions.  相似文献   

南极菌Pseudoalteromonas sp．S-15-13产胞外多糖的研究及其分子鉴定   总被引：2，自引：1，他引：2       下载免费PDF全文

李江  陈靠山  林学政  李光友 《极地研究》2006,17(2):130-135

本文对影响南极细菌S-15-13生长和胞外多糖产量的主要环境因子进行了研究,同时采用16S rDNA序列分析及系统发育分析方法对其进行了分子鉴定。结果表明：菌株S-15-13最佳产糖条件为：培养时间,56h；培养温度,8℃；碳源,1．0%葡萄糖；NaCl浓度,3．0%；pH,6．0-7．0。16S rDNA序列分析和系统发育分析表明,菌株S-15-13属于假交替单胞菌属(Pseudoaltero- monas)。  相似文献   

江西省会昌县苦竹岽锡矿地质特征及矿山探(采)结合初探     

张庆林  何桂红 《华东地质学院学报》2006,(Z1):167-171

苦竹岽锡矿位于密坑山杂岩体北西部边缘与侏罗系上统鸡笼嶂组火山岩接触部位,明显受近东西向、南北向断裂带和接触带三者控制,为岩浆期后高中温气化热液微细脉浸染型矿床。在矿山探(采)过程中,进一步分析研究了锡矿的控矿因素和矿体的变化规律,指导矿山探(采)工程的布置,收到良好的效果,对今后矿山的探(采)工作具有较大的现实意义。  相似文献   

桩锚支挡体系在广西寨-任二级公路高边坡治理工程中的应用   总被引：3，自引：0，他引：3  

胡华敏  胡杰刚  俞敏  全洪波  兰高 《中国地质灾害与防治学报》2006,17(3):150-153

(六)寨-(水)任二级公路施工后,滑坡、坍塌、崩塌现象甚多,边坡治理迫在眉睫。桩锚支挡体系是一项主动性加固边坡技术,具结构轻巧、用材合理、施工简单、工期短、费用低等特点。论文通过其在(六)寨-(水)任二级公路K56段高边坡治理工程中的应用,对桩锚支挡体系的设计及施工要点作了介绍。  相似文献