281 resultados para 6 methoxyluteolin 7 o beta dextro allopyranoside
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视觉检测技术是随着计算机视觉技术和光电技术的飞速发展,而出现的一种新的检测技术。检测被测目标时,把图像当作检测和传递信息的手段或载体,从图像中提取有用的信号,它是以现代光学为基础,融光电子学、计算机图像学、信息处理、计算机视觉等科学技术为一体的现代检测技术。现代激光自动化焊接技术是由激光、计算机、机器人、数控和精密机床等相结合的综合高新技术,此项技术已成为工业生产自动化的关键技术,拥有普通加工技术所不能比拟的优势。为了克服机器人焊接过程中各种不确定因素对焊接质量的影响,提高机器人作业的智能化水平和工作可靠性,要求焊接机器人系统不仅能实现空间焊缝的实时跟踪,而且还能实现焊接参数的在线调整和焊缝质量的实时控制,即焊接机器人焊接过程的自主化和智能化。本文的研究依托于中国科学院知识创新工程方向性项目“全自动激光拼焊成套装备生产线”,旨在探索立体视觉检测系统的实现及其在激光拼焊工程中的应用的问题。从理论和实践两个方面,对其中的若干关键技术,如视觉检测系统创新设计、数学模型、量化误差、摄像机标定、结构光条纹中心线提取、焊前特征检测、溶池边缘提取、焊后缺陷图像匹配算法、三维重建和表面孔的视觉定位等进行了研究。主要研究成果如下: 1.提出了一种可以用于焊前跟踪,焊后检测,以及焊接过程中对激光溶池进行监测的多功能激光视觉检测装置。推导了检测系统在不考虑像平面安装倾斜角度时和考虑像平面安装倾斜角度时检测点坐标的计算公式以及量化误差公式,分别针对由于数模转换量化误差、安装角度倾斜误差、安装高度误差三个方面引起的量化误差,分析其关于行,列,以及不同倾斜角度的影响分布规律。并对于各种情况进行了仿真,对于各种误差分布特征进行了分析,提出了检测奇异点的情况和数学模型的局限性。以上工作为实现焊缝三维信息的高精度提取奠定了基础。 2.对于摄像机的标定技术进行了研究,结合工程实际,利用zhang的标定法和matlab标定工具包,对于摄像机进行了标定;针对检测相机视场较小,标定采集范围不易调整和相机的畸变主要发生在视场边缘等特征,在保证要求的精度范围之内,提出一种基于标定靶的标定方法,实验证明该方法的标定与测量精度能够满足工程需要。 3.研究了现有的条纹中心提取算法过程,提出了基于OTSU阈值的多次高斯拟合平均法和基于OTSU阈值的质心平均法计算激光条纹中心坐标。该法对条纹的噪声,散斑和被测工件表面漫反射有很强的抵制作用,因此具有很强的鲁棒性。实验表明,与传统方法相比,具有更高的提取精度。同时为了适应激光条纹被工件表面调制后发生的角度变化,以及硬件安装带来的激光线型条纹倾斜,提出了一种自适应方向模板法,可以解决特殊倾斜角度时的激光条纹中心线提取问题。三个仿真试验验证了方法的可行性。 4.提出了一套在线实时进行焊前检测的图形处理算法,可以实现焊缝宽度,焊前错配和焊缝中心位置检测。通过工程实验提取了各指标的检测结果,并验证了算法的正确性。 5.提出了一种基于数学形态学的激光拼焊溶池边缘检测算法,对于激光拼焊中的溶池图像进行边缘提取,基于真实图像进行了实验研究表明,提取边缘效果可以达到单像素。 6.对焊后表面形貌检测的图像实时处理算法进行了研究。提出了一套在线实时进行焊后焊缝表面缺陷检测的图形处理算法,可以进行焊缝宽度,错配,凹度,凸度,咬边,焊接倾角,过高七种表面焊接缺陷的匹配识别;对于整个焊缝的表面形貌进行三维重建。通过等厚板焊接和不等厚板焊接两种试验,验证了算法的合理性和鲁棒性。提出了一种基于randon变换的错配和兴趣区域快速检测算法。对于表面孔的检测算法进行了探讨,主要针对孔的检测中的噪声和表面反射,研究了腐蚀膨胀对于表面孔定位和大小的检测影响。 7.研究了以普通6R机器人进行焊缝视觉检测的工作视野,即焊缝视觉检测空间,提出了一种生成焊缝视觉检测空间的解算法;以此检测视野为依托,探索了在视觉检测视野中进行焊缝视觉检测的初始位置规划问题,提出了一种初始位置规划算法;仿真结果证明了算法的正确性。
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The coda of seismic waves consists of that part of the signal after the directly arrivials. In a finite medium, or in one that is strongly heterogeneous, the coda is dominated by waves which have repeatedly sampled the medium. Small changes in a medium which may have no detectable influence on the first arrivals are amplified by this repeated sampling and may thus be detectable in the coda. Because of this, coda wave is widely used in detecting micro variations in medium。 In this paper, we give a general view of the theory and application of coda wave, especially coda wave interferometry. We focus on discussing the application of coda wave interferometry on data source of active situ experiment。 First, we apply coda wave interferometry in a short time period situ experiment which last for three days. We also apply the method of coda wave interferometry in a situ experiment which last for one month. Daily circle variations of seismic velocity around the experiment site were obtained, and we also observed that the velocity variations in the experiment site have a significant correlation with the environment factors, including air temperature, barometric pressure, solid earth tide and the level of rainfall. We find that the velocity variation during this period is up to 10-3. The relationship between velocity variation and changes in air temperature, barometric pressure and solid earth tide was analyzed with least square linear fitting .The velocity has no dependence on the air temperature. But velocity has a change of 10-6--10-7 when the barometer or earth tide change per Pa. Generally, we conclude the work and results of previous researchers, and we also display our works and results. We hopes to contribute to the future research of coda wave interferometry.
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On the basis of the character of sedimentation and reservoir researching as well as diagenesis, using conventional and update testing measures, classificati-on and evaluation of the tesla low permeability reservoir in Ordos Basin is pr-esented. From Chang 8 to Chang 4+5 oil formations, four facies developed, includi-ng alluvial fan facies, delta facies, lake facies as well as density current. They were controlled by the northeastern, the southwest, the southern and the northwestern provenances. Distributary channel underwater and mouth bar of delta fr-ont are the main reservoirs. Detrital component has the different character in s-outh and in north. Sedimentary system in the northeastern part has more felds-par and less quartz. Sedimentary system in the southern part has more quartz and less feldspar. Because of sedimentation and diagenesis, the oil formations in region of interest formed the different features of pore array of the tesla l-ow permeability reservoirs. After researching, it is found that the active porosity and the main throat radius of Chang 4+5 are the highest, and they are positive correlation with per-meability. The exponent of flowing interval falls in the sortorder: Chang 8, Chang 4+5, Chang 6, Chang 7. Using clustering procedure and quaternion, the reservoirs of Yanchang for-mation in Ordos Basin are divided into five types. Ⅰ-good reservoirs and Ⅱ-appreciably good reservoirs occur in distributary channel and mouth bar. Ⅲ-poor reservoirs and Ⅳ-poorer reservoirs exist in natural levee, crevasse splay under-water and turbidity fan. It is forecasted that the oil area in Ⅰ-good reservoirs is about 4336.68 square kilometers, and the oil area in Ⅱ-appreciably good reservoirs is 28013.28 square kilometers or so, and the oil area in Ⅲ-poor rese-rvoirs is 28538.05 square kilometers more or less.
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Jiaodong Peninsula is the largest repository of gold in China. Varieties of studies have been involved in the mechanism of metallogenesis. This thesis is a part of the project "Study of basic geology related to the prespecting of the supra-large deposits" which supported by National Climbing Program of China to Prof. Zhou. One of the key scientific problems is to study the age and metallogenic dynamics of ore deposit and to understand how interaction between mantle and crust constrains on metallogenesis and lithogenesis. As Jiaodong Peninsula to be study area, the Rb-Sr, Sm-Nd and Pb isotopic systematics of pyrite and altered rocks are measured to define the age and origin of gold. The elemental and Sr-Nd-Pb isotopic compositions of dikes and granites was studied to implicate the source and lithogenesis of the dike and granite and removal of lithosphere and the interaction between mantle and crust in the Jiaodong Peninsula. Considering the tectonic of Jiaodong Peninsula, basic on the time and space, this thesis gives a metallogenic dynamics of gold mineralization and discusses the constraints of the interaction between mantle and crust on the metallogenesis and lithogenesis. This thesis reports the first direct Rb-Sr dating of pyrites and ores using sub-sampling from lode gold deposit in Linglong, Jiaodong Peninsula and the results demonstrate this as a useful geochronological technique for gold mineralization with poor age constraint. The Rb-Sr data of pyrites yields an isochron age of (121.6-122.7) Ma, whereas, those of ore and ore-pyrite spread in two ranges from 120.0 to 121.8 Ma and 110.0-111.7 Ma. Studies of characteristic of gold deposit, microscopy of pyrite and quartz indicate that the apparent ages of ore and ore-pyrite are not isochron ages, it was only mixed by two end members, i.e., the primitive hydrothermal fluids and wall rocks. However, the isochron age of pyrite samples constrains the age of gold mineralization, i.e., early Cretaceous, which is in good consistence with the published U-Pb ages of zircon by using the SHRIMP technique. The whole rock Rb-Sr isochron age of altered rocks indicates that the age of gold mineralizing in the Xincheng gold deposit is 116.6 ± 5.3 Ma. The Sr, Nd and Pb isotopic compositions of pyrite and altered rocks indicate that the gold and relevant elements were derived from multi-sources, i.e. dikes derived from enriched lithospheric mantle and granites, granodiorites and metamorphic rocks outcropped on the crust. It also shows that the hydrothermal fluids derived from mantle magma degassing had play an important role in the gold mineralizing. The major and trace elements, Sr-Nd-Pb isotopic data of granites and granodiorites suggest that the Linglong Granite and Kunyushan Granite were derived from partial melting of basement rocks in the Jiaodong Peninsula at post-collision of North China Craton with South China Craton. Guojialing Granodiorite was considered to be derived from a mixture source, that is, mixed by magmas derived from an enriched lithospheric mantle and crust during the delamination of lithosphere induced by the subduction of Izanagi Plate and the movement of Tancheng-Lujiang Fault. There are kinds of dikes occurred in the Jiaodong Peninsula, which are accompanying with gold mineralization in time and space. The dikes include gabrro, diabase, pyroxene diorite, gabrrophyre, granite-porphyry, and aplite. The whole rock K-Ar ages give two age intervals: 120-124 Ma for the dikes that erupted at the gold mineralizing stage, and <120 Ma of the dikes that intruded after gold mineralizing. According to the age and the relationship between the dikes and gold mineralizing, the dikes could be divided into two groups: Group I (t = 120-124 Ma) and Group II (t < 120Ma). Group I dikes show the high Mg and K, low Ti contents, negative Nb anomalies and positive Eu anomalies, high ~(87)Sr/~(86)Sr and negative εNd(t) values and an enrichment in light rare earth elements, large ion lithosphile elements and a depletion in high field strength elements. Thus the elemental and isotopic characteristics of the Group I dikes indicate that they were derived from an enriched lithospheric mantle perhaps formed by metasomatism of the melt derived from the recycled crustal materials during the deep subduction of continent. In contrast, the Group II dikes have high Ti, Mg and K contents, no negative Nb anomalies, high ~(87)Sr/~(86)Sr and positive or little negative εNd(t) values, which indicate the derivation from a source like OIB-source. The geochemical features also give the tectonic constraints of dikes, which show that Group I dikes were formed at continental arc setting, whereas Group II dikes were formed within plate background. Considering the tectonic setting of Jiaodong Peninsula during the period of gold mineralizing, the metallogenic dynamics was related to the subduction of Izanagi Plate, movement of Tancheng-Lujiang Fault and removal of lithopheric mantle during Late Mesozoic Era.
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Mafic granulite xenoliths have been extensively concerned over the recent years because they are critical not only to studies of composition and evolution of the deep parts of continental crust but to understanding of the crust-mantle interaction. Detailed petrology, geochemistry and isotope geochronology of the Early Mesozoic mafic-ultramafic cumulate xenoliths and mafic granulite xenoliths and their host diorites from Harqin area, eastern Inner-Mongolia have been studied here. Systematic Rb-Sr isochron, ~(40)Ar-~(39)Ar and K-Ar datings for mafic-ultramafic cumulate xenoliths give ages ranging from 237Ma to 221Ma. Geochemical research and forming temperature and pressure estimates suggest that cumulates are products of the Early Mesozoic mantle-derived magmatic underplating and they formed in the magmatic ponds at the lowermost of the continental crust and are later enclaved by the dioritic magma. Detailed study on the first-discovered mafic granulite xenoliths reveals that their modal composition, mineral chemistry and metamorphic P-T conditions are all different from those of the Precambrian granulite exposed on the earth surface of the North China craton. High-resolution zircon U-Pb dating suggests that the granulite facies metamorphism may take place in 253 ~ 236Ma. Hypersthene single mineral K-Ar dating gives an age of 229Ma, which is believed to represent a cooling age of the granulite. As the host rock of the cumulate and granulite xenoliths, diorites intruded into Archean metamorphic rocks and Permian granite. They are mainly composed of grandodiorite, tonalite and monzogranite and show metaluminous and calc-alkaline features. Whole rock and single mineral K-Ar dating yields age of 221 ~ 223Ma, suggesting a rapid uplift in the forming process of the diorites. Detailed field investigation and geochemical characteristics indicate that these diorites with different rock types are comagmatic rocks, and they have no genetic correlation with cumulate and granulite xenoliths. Geochemical model simulating demonstrates that these diorites in different lithologies are products of highly partial melting of Archean amphibolite. It is considered that the Early Mesozoic underplating induced the intrusion of diorites, and it reflects an extensional geotectonic setting. Compression wave velocity V_P have been measured on 10 representative rock samples from the Early Mesozoic granulite and mafic-ultramafic cumulate xenoliths population as an aid to interpret in-situ seismic velocity data and investigating velocity variation with depth in a mafic lower crust. The experiments have been carried out at constant confining pressures up to 1000MPa and temperatures ranging from 20 ℃ to around 1300 ℃, using the ultrasonic transmission technique. After corrections for estimated in situ crustal pressures and temperatures, elastic wave velocities range from 6.5 ~ 7.4 km s~(-1). On the basis of these experimental data, the Early-Mesozoic continental compression velocity profile has also been reestablished and compared with those of the present and of the different tectonic environments in the world. The result shows that it is similar to the velocity structure of the extensional tectonic area, providing new constraints on the Early Mesozoic continental structure and tectonic evolution of the North-China craton. Combining with some newly advancements about the regional geology, the thesis further proposes some constraints on the Mesozoic geotectonic evolution history, especially the features of deep geology of the North China craton.
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"富台潜山裂缝油藏定量表征和预测"是中石化集团总公司"十五"科技攻关课题,也是国际攻关学科前沿难题,工作量大,有重要理论意义和实用价值。综合应用石油构造地质学、岩石力学、储层地质学、石油地质学、地震地层学,测井地质学、数学地质和油藏工程等多学科理论为指导,将地质、地震、测井、试油试采和油藏工程等信息相结合、露头区和覆盖区相结合、油区、油田和油藏地质模型相结合,最大限度应用计算机手段,研究、描述和表征目的层油藏内幕构造,储层几何形态、空间形成机制分布和非均质性,实现露头规模、岩心规模、微观规模裂缝网络定量表征,揭示岩溶作用类型形成机制和分布规律,开展潜山裂缝三重孔隙结构测井储层评价,揭示流体性质和分布规律,建立潜山油藏露头规范、岩心数模静态地质模型,潜山油藏三重孔隙结构地质模型和潜山油藏预测地质模型,指导油田开发,降低开发成本,大幅度提高开发效益。取得的主要成果创新是:1.建立了研究区下古生界地层格架,揭示了下古生界储层几何形态、空间分布和形成机制。2.首次提出富台潜山是中生代逆冲挤压、走滑和新生代伸展、走滑两个构造系统叠加复合的产物,是逆冲断层控制的断展背斜。储集空间主要是断展背斜上经风化、溶蚀改造近SN、EW走向的纵、横张裂隙,其次是被改造的两组平面X剪裂缝。3.建立了富台潜山裂缝油藏燕山期、喜山期四维应力场模型,预测了研究区张破裂和剪破裂带分布规律。4.论述了研究区岩溶作用模型,揭示了岩溶作用与成藏的关系。5.建立了研究区露头规模、岩心规模、微观规模、测井裂缝和有效裂缝网络预测模型,预测了裂缝发育分布规律。6.建立了三重孔隙结构测井储层预测模型。生产检验符合率为80%。7.建立了富台潜山油藏静态、动态和预测模型,预测了裂缝带的分布。8.开发了一套潜山油藏研究、描述、表征和预测的理论、方法和技术,发展了陆相断陷湖盆的理论、方法和技术,有极大的推广价值。
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我国东南四省广泛分布着大量的富铀花岗岩.是氡的高本底区。人防工程因其建于地下.室内氡浓度受本底值影响更大。为了解该地区地下人防工程内氡的浓度水平及可能对人体产生的危害.文章对该区11个城市30个不同类型的人防工程室内氡浓度进行了约24小时连续测定。测定结果为11.1~344.1BQ·m^-3,平均值为70.5Bq·m^-3。为探讨工程的地质概况、被覆程度、被覆材料及通风程度对室内氡浓度的影响,根据工程被覆程度及人员使用频繁程度将其分为四类:地下停车场(Ⅰ类);超市。办公室等(Ⅱ类);被覆坑道(Ⅲ类);毛洞(Ⅳ类)。各类工程的氟浓度平均值分别为29.6、33.7、84.4、137.5Bu·m^-3。
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对贵阳市和武汉市的5座城市生活垃圾填埋场大气中的ρ(气态总汞)进行了测定,并分析了填埋场的大气活性气态汞、颗粒态汞、单甲基汞和二甲基汞的质量浓度分布.结果表明:5座填埋场ρ(气态总汞)为1.6~473.7 ng/m3,不同采样点的平均值为8.5~155.7 ng/m3,最高值出现在填埋场的工作面及工作面下风向区域;而封闭填埋场或运行填埋场的覆土区的ρ(气态总汞)较低.天气条件和垃圾处理活动均可影响ρ(气态总汞)水平.贵阳高雁垃圾填埋场大气ρ(活性气态汞),ρ(颗粒态汞),ρ(单甲基汞)和ρ(二甲基汞)的平均值分别为37.4,255.3,12.4和12.7 pg/m3.虽然不同形态汞的质量浓度明显高于全球背景值,但其产生的环境风险不大.
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采用6种萃取剂:pH=7的0.01mol/L CaCl2、pH=7.3的0.005mol/L DTPA+0.1mol/L TEA(三乙醇胺)+0.01mol/L CaCl2、0.1mol/L NaNO3、0.43mol/L HOAc、pH=7的0.05mol/L EDTA和pH=4.65的0.5mol/L NH4OAc+0.01mol/L EDTA浸取液,对污染土壤中的重金属Cu、Zn、Cd、Pb的进行了萃取,并比较了萃取剂的萃取能力。实验结果表明,HOAc、EDTA以及NH4OAc-EDTA萃取各种重金属的能力远远大于其它几种萃取剂的萃取能力,是比较理想的萃取剂。
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使用浓HNO,+HF混合液和浓HNO,液分别在高压密闭罐中消解土壤、沉积物、岩石和植物样品,6mol/LHCL加热还原样品后用氢化物发生-原子荧光光谱法(HG-AFS)测定样品中的硒。使用该法对土壤标准参考物质GSS-4、GSS-5、GSS-6、GSS-7和植物标准GSV-1、GSV-3进行了分析,硒的测定结果与推荐值一致。加标回收实验的回收率在98.0%~101.4%,平均为99.8%。实测样品中的硒与中子活化分析(NAA)和氢化物-多接受杯质谱计(HG-MC-ICP-Ms)的分析结果基本一致,表明该法平行样的重现性好,分析速度快,提高了硒分析的准确度和分析精度。
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云南会泽超大型铅锌矿床规模大、品位富、伴生有用元素多,预示其成矿环境较为特殊。本文分析该矿床矿石中脉石矿物方解石和赋矿碳酸盐地层的C、O同位素组成,结果表明矿石中脉石矿物方解石的C、O同位素组成相对均一,不同矿体(不同标高)、不同产状以及相同矿体不同产状方解石的C、O同位素组成不具明显差别,其δ^13CPDB值和δ^18 OSMOW值分别为-2.1‰~-3.5‰(均值-2.8‰)和16.7‰~18.6‰(均值17.7‰),在δ^13CPDB-δ^18OSMOW图上集中于岩浆碳酸岩与海相碳酸盐岩之间的狭小范围内。多方面的证据表明:矿床成矿流体为壳一幔混合流体,其中壳源组分可能主要由矿区(或区域)碳酸盐地层提供,而幔源组分则可能与区域大面积峨眉山玄武岩岩浆活动过程中的去气作用有关。
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铊(含铊)矿床系指包括Tl、Hg、As、S、Sb、Cu、Ph、Zn、Cd、Ge、Sn、Au和Ag等在内的一套亲铜族元索矿床系列。基于铊地质地球化学,环境地球化学和生物地球化学研究基础,并以铊矿床为例,从铊(含铊)矿物、元素组合、多岩性岩、生物成矿、表生地球化学等5个方面进行了阐述。
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在相同的物理化学(常温、常压、氧化)环境中,用大气降水分别对两块相似的硫化物矿石样品进行蒸发或淋漓实验,模拟干旱地区和潮湿地区的岩矿石风化作用。实验共进行603d。实验结果显示:经蒸发实验的样品无论是硬度、颜色和矿物组成等都发生了明显的变化,而经淋漓实验的样品无论硬度、颜色和矿物成分等基本保持实验前的特征;作蒸发实验浸泡液的pH值先降后升,最后稳定在6.5~7,而作淋漓实验淋漓液的pH先降,然后稳定于5左右,浸泡液的阳离子浓度却比淋漓液的高。实验结果表明蒸发作用比淋漓作用更容易使岩矿石风化。蒸发作用主要是化学反应。所以,这一实验结果向干旱地区主要是物理风化的传统认识提出了的挑战。
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城市生活垃圾填埋场作为大多数国家生活垃圾的主要处理场所,也常常成为一些有毒有害元素的最终归宿地。很多含汞的废弃产品,如荧光灯管、电池、水银温度计、压力计、电开关、恒温器等,在缺乏分类回收的情况下,大多混入城市生活垃圾并最终进入垃圾填埋场。在填埋场这一特殊场合,汞可以通过物理途径、化学途径、生物途径或不同途径的结合而向大气释放,并且还可能在填埋场内形成毒性很高的甲基形态汞而释放到大气中。国外对垃圾的焚烧处理已经造成了严重的大气汞污染,但是目前对垃圾填埋场向大气释放汞的研究在国内外还不多见,我国几乎还是空白。作为城市生活垃圾的生产大国,我国每年的生活垃圾产量超过1.5亿吨,占世界的1/4以上,且近九成是以填埋法进行处理的,因此研究垃圾填埋场这一人为源向大气排放汞的通量和形态、排放汞的特点以及相关的影响因素,必将为认识该释放源对大气汞的贡献以及评估其对生态环境的影响程度提供重要的参考依据,并为制定控制垃圾填埋场汞污染的相关措施提供指导,本文在理论上和现实上都具有重要意义。 2003年10月份到2006年1月份,我们对贵阳市和武汉市的5座城市生活垃圾填埋场进行了野外实地研究。这几个填埋场包括贵阳市的高雁、大转弯、仙人脚,以及武汉市的金口和岱山垃圾填埋场,它们采用不同的垃圾填埋方式(卫生填埋和简易填埋)并处于不同的运行阶段(封闭的和运行中的)。本文从两个方面开展研究:(1)垃圾填埋场通过地表向大气释放汞的通量;(2)垃圾填埋场向大气释放汞的形态。前者利用低汞空白的石英玻璃动力学通量箱法,结合高时间分辨率的大气自动测汞仪(Tekran 2537A),现场对填埋场内不同特征的地表区域(绿化区、覆土地表、裸露生活垃圾、工作面等)进行了测定;后者利用不同的捕集材料(金管、稀HCl溶液和CarbotrapTM捕集管),对排气筒垃圾填埋气中的不同形态汞(气态总汞、单甲基汞和二甲基汞)进行预富集,并结合气相色谱、冷原子荧光等检测技术进行测定。根据同步测定的相关参数对垃圾填埋场向大气释放汞的过程和影响机制进行了探讨,对垃圾填埋场向大气的排汞量进行了估算。另外对垃圾填埋场周围环境介质中的汞分布特征进行了探讨。通过两年多的野外工作,得到以下主要结论: (1)垃圾填埋场地表与大气间的汞交换通量主要以向大气的释放为主,少数情况下(如降雨、大气汞浓度较高时)也会出现大气向地表的沉降。地表/大气间的汞交换过程具有明显的日变化特征,一般在白天中午前后达到最高,夜间降至最低,并维持在稳定的水平。汞交换过程主要与光照等气象因子有关,通量强度白天高于夜间、晴天高于阴雨天。另外,通量还与基质中的汞含量密切相关,汞含量越高,排放强度越大,生活垃圾的汞含量一般高于覆盖土壤,因而裸露的生活垃圾或工作面区域汞释放强度明显高于有土壤覆盖的区域。绿化措施(植草和种树)有效的降低了汞的释放。垃圾填埋场地表汞的释放强度暖季节高出冷季节数倍。地表/大气间的汞交换通量特征显示,垃圾填埋场向大气释放汞的主要来源为上层基质,而非填埋场内部,由于覆土隔离层的屏障作用使得填埋场内部的气态汞很难垂直向上迁移和释放。垃圾填埋场的汞释放强度与城市规模以及经济发展水平没有直接相关性。 (2)垃圾填埋场地表/大气间的汞交换通量强度由于以上因素的影响,在不同地表区域以及不同时段内都可能发生很大变化。封闭的垃圾填埋场地表/大气间的汞交换通量最高出现在汞污染的覆土区,其次为未污染的覆土区,最低为绿化区,三种区域平均的汞交换通量分别为112.8~559.1、50.7~53.6、19.7 ng Hg m-2 h-1。运行中的垃圾填埋场地表/大气间的汞交换通量最高为裸露垃圾区和工作面,最高达5609.6 ng Hg m-2 h-1,平均为57.5~664.6 ng Hg m-2 h-1;其次为老的覆土区,平均为19.6~192.5 ng Hg m-2 h-1;新盖覆土区最低,平均为-1.4~27.8 ng Hg m-2 h-1。垃圾填埋场的工作面具有最大的汞释放潜力,但是因大气汞浓度较高以及波动较大等原因,动力学通量箱法无法真实测定该区域的汞释放强度,运用美国环保局提供的面状复合工业污染源模型(ISCST3)对工作面的汞释放强度估算显示,不同天气状况下的平均释汞因子为0.93 mg Hg t-1垃圾。与全球以及区域背景土壤相比,垃圾填埋场向大气的单位面积释汞强度要高出数倍乃至数千倍。因而城市生活填埋场必将对大气汞环境,特别是局域大气汞环境造成一定影响。 (3)垃圾填埋场排气筒释放的垃圾填埋气中不同形态汞的浓度差别很大。高雁、金口和岱山垃圾填埋场排气筒的气态总汞浓度为2.0~1406.0 ng Hg m-3,3座填埋场平均分别为89.8、24.6和14.2 ng Hg m-3。气态总汞浓度主要与排气筒附近的垃圾汞含量有关,并表现出一定的日变化特征,晴天比较稳定,降雨过程中上升很快,降雨过后又恢复到降雨前的水平。这一有趣现象主要与降雨时雨水置换填埋场内的含汞气体、大气压下降、通过地表释放的通道受阻有关。高雁垃圾填埋场垃圾填埋气中的单甲基汞和二甲基汞平均浓度为1.93 ng Hg m-3和9.21 ng Hg m-3,分别占同期气态总汞的0.51%和1.79%。垃圾填埋气中的甲基形态汞浓度高出背景区域大气3个数量级以上,使得垃圾填埋场成为大气甲基汞已知不多的、重要的释放来源之一。 (4)结合垃圾填埋场不同特征地表的面积以及对应的汞交换通量强度、工作面的垃圾处理量以及汞的释放因子,估算本研究的5座垃圾填埋场每年通过地表向大气的释汞量为17~1111 g Hg yr-1,工作面贡献67%~91%,覆土区较少,绿化区最少。根据垃圾填埋气的产量以及其中不同形态汞的含量,估算高雁、金口和岱山垃圾填埋场每年通过排气筒向大气的排汞量在1~2 g Hg yr-1之间;高雁填埋场通过排气筒每年向大气释放的单甲基汞和二甲基汞为20和90 mg Hg yr-1。垃圾填埋场向大气释放汞的通道主要为地表,而排气筒的贡献仅为0.2%左右(地表+排气筒)。对全国垃圾填埋场进行的初步估算显示,2004年我国这一人为源向大气的排汞量约为600 kg Hg yr-1,占我国大气人为汞释放源的1%以下。 (5)垃圾填埋场大气中的不同形态汞浓度明显高于全球背景值,但与区域大气相当或稍高一点,部分区域有轻微污染,总体而言属于“安全”浓度范围。城市生活垃圾中的汞含量分布极不均匀,浓度为0.170~46.222 mg kg-1,几何均值0.574 mg kg-1,个别异常偏高的样品可能是被含汞的废弃产品污染了,大部分垃圾汞含量低于0.5 mg kg-1。不同垃圾填埋场覆盖土壤的汞含量差异显著,反映了填埋场所在区域的土壤背景值以及垃圾填埋活动对覆盖土壤的污染程度,有时覆土的汞含量超过区域土壤背景值的2~23倍。填埋场生长的植物因生活习性的不同汞含量分布特征也不同。高雁垃圾填埋场产生的渗滤液汞含量较低,为79.4 ng l-1,主要因为垃圾汞含量低、渗滤液呈碱性、难溶硫化物的形成以及有机/无机物对汞的吸附等。以高雁垃圾填埋场为例进行的质量平衡计算显示,每年排向渗滤液和大气的汞分别占每年输入填埋场总量的0.004%和0.3%,其余超过99%的汞仍然保留在垃圾填埋场的固体废物中,这一特点使得垃圾填埋场向大气的排汞量远低于垃圾焚烧法,后者由于高温作用使得垃圾中的汞几乎全部挥发进入大气。 (6)减少垃圾填埋场汞污染的措施包括:从源头上杜绝含汞的进入,如减少含汞产品的生产和使用,对含汞废弃产品进行专门的收集和处理;垃圾填埋以后及时进行覆土和绿化,特别是在工作面,应争取做到每日覆土;垃圾填埋场产生的气体应收集和处理,将其进行焚烧(沼气发电)可以分解其中的甲基形态汞,降低其毒性。
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“对元素和物质类型进行探测”是我国嫦娥一号探月卫星对月球进行探测的四大科学目标之一。本文主要是针对“对元素和物质类型进行探测”这一主要科学目标,进行如何利用嫦娥探月卫星相应有效载荷的科学数据反演月表物质成分预研究。本文的内容主要包括如下的几方面: (1)对月球的化学元素、矿物和岩石的基本组成、性质与特征等方面进行了较为详细的叙述。 (2)对如何利用干涉成像光谱仪的数据反演元素含量进行了预先研究。首先提出了反演Ti含量的技术路线。同时采用月球采样点的双向反射数据替代相应的月球样品半球反射率的方法的主导思路,较为成功地对Le Mouéic等月表FeO定量方法进行了精炼,并且对于改进过程发现的问题,提出了解决的方法。 (3)利用国家天文台兴隆基地2.16m光学望远镜,在国内首次对月球表面进行了观测,观测区域为月表的采样点附近等。通过这段时间的观测,不仅积累了采样点附近区域等的光谱数据,相应的为如何利用我国嫦娥工程的科学数据进行物质反演奠定基础,而且为以后进一步的对月进行地基望远镜观测积累了实践经验等。 (4)为了更好的应用干涉成像光谱仪科学数据进行相关的月球科学研究,就必须进行数据的校正,即数据预处理。本文通过对不同光谱标准方案进行分析和比较,以及采用地基望远镜的观测数据进行实验,我们选取了进行光谱校正的标准光谱。 (5)同样为了对干涉成像光谱仪的科学数据的光度校正做好充分的准备,选择了适合于我们干涉成像光谱仪科学数据的光度校正函数,并且进行了光度校正的预演。 (6)嫦娥月球探测工程的科学数据为月球科学家们实现全月球表面主要矿物(辉石、斜长石、橄榄石和钛铁矿)的填图提供了新的契机。根据我国的伽玛射线谱仪,X射线谱仪数据和干涉成像光谱仪数据各自的特点,把这些数据进行数据融合,实现对月表主要矿物的反演预研究工作,并且提出了实现这一目标的较为具体的技术路线。 (7)在已经完成的月表主要矿物反演预研究的基础上,分为三种情况提出了对月球表面的岩石类型进行划分的方案,即,对月表克里普岩的反演、对月表高地岩石类型的反演和对月表的月海玄武岩类型的反演。