西安市大气降尘中石膏的成因与环境意义

运用X射线粉末衍射、红外光谱、扫描电镜、激光粒度仪和硫同位素分析等方法对西安市11个采样点大气降尘中石膏等矿物进行研究,表明石膏矿物是在大气环境中形成。西安市大气降尘中石膏含量范围0～20％,平均6．3％,多为呻级自形微晶。降尘中硫同位素组成与其硫含量负相关;同时,降尘硫含量（平均SO2含量6％）远远高于源区物质（平均0．94％）,说明其主要来自大气气相硫。结合降尘微形貌特征与SO2含量的关系分析,降尘中的SO2含量不仅受粒度控制,还与大气降尘的种类和性质有关。降尘对空气中SO2的“捕捉作用”具有不均匀性,可以影响和改变城市大气中S元素的分布、传输路径和沉积方式。加强对大气降尘环境矿物学研究,查清大气降尘矿物成分及其组合的时空变化,对探索含硫污染物的演化轨迹和评价含硫污染物的环境危害性具有重要意义。     

淄博市大气降尘矿物组合特征及其环境意义

用多晶X-射线衍射法对淄博市中心城区逐月采集的大气降尘矿物组成及其含量进行了分析。研究结果表明:淄博市大气降尘的矿物组合比较稳定,降尘中以源于自然成因的石英、长石和粘土质矿物为主,质量分数变化范围为59.1%～95.1%。降尘中的石膏和方解石与大气化学反应有关,其中石膏质量分数为36.3%～1.0%,反映了大气SO₂污染具有明显的时间性特征。降尘中的赤铁矿源于高温工业活动,含量变化幅度最小。气象因素可能是导致降尘中石膏含量变化的主要原因,降尘中石膏含量的变化是大气酸污染程度的重要矿物指示剂。     

城市环境大气降尘重金属研究进展

大气降尘重金属研究是对城市环境及其生态效应评估的重要手段之一。概述了大气降尘来源,对比了国内外降尘重金属含量及通量、重金属源的解析方法。同时指出了关于大气降尘重金属的国内外研究概况和进展,为今后城市环境大气降尘研究等相关领域提供借鉴。     

环境矿物学：矿物学在环境科学研究中的应用

矿物学在环境科学中的应用将是21世纪矿物学研究的一个主要方面。 作者所在实验室曾做过的一些环境矿物学研究的实例有：核废料的处置,矿物表面性质的研究,对有毒金属的还原和固定作用的微生物效应,大气烟尘微粒的研究,矿物表面阳离子的本征吸附常数之理论计算,等等。矿物-水-微生物体系在分子级别上之相互作用的定量研究,对于理解低温地球化学和生物地球化学过程将是重要的。     

石家庄市东南部近地表降尘的矿物学特征与环境意义

大气降尘可以危害生态环境和人体健康。矿物颗粒不仅是大气降尘的主要组成物质,也是鉴定其污染来源的关键标记,因此查明大气降尘中的矿物组成对改善生态环境具有重要指导意义,也可为防治大气降尘和保护环境提供合理的参考依据。本文选取石家庄东南部作为研究区,利用X射线衍射技术(XRD)和配有能谱的扫描电镜(SEM-EDX)检测大气降尘中的矿物成分、化学组成和微观形貌。结果表明,石家庄东南部大气降尘中颗粒物的形状有片状、柱状、板状、球状等。矿物种类包括硅酸盐、碳酸盐、硫酸盐,以及以往报道较少的氟磷酸盐。以上矿物颗粒既有自然来源,也有人为来源,其中与人类活动相关的来源包括建筑材料、燃煤以及机动车排放等。     

合肥市大气颗粒物组成及其环境指示意义

化学组成、微量元素、X-射线粉末衍射、红外吸收光谱、扫描电镜分析等研究，显示合肥市各个取样点大气颗粒物组成基本稳定，矿物组成为：伊利石、石膏、绿泥石、石英、长石、方解石、白云石、无定型非晶质物，具有异常的钙、钴、铜、铅、锌含量，主要为微米粒级颗粒，综合分析结果揭示合肥地区大气颗粒物主要源于水泥工业和交通造成的污染，部分来源于地面扬尘和工业窑炉。大气降尘中较多石膏（大于10%）的存在，说明大气SO2污染比较严重。     

唐山市曹妃甸地区大气降尘矿物学特征及环境意义——以华北理工大学校区为例

大气降尘矿物学特征研究具有重要的环境学意义。文章以华北理工大学校区采集样品为例,应用激光粒度分析仪、扫描电镜、X射线粉末衍射、电感耦合等离子体质谱等对河北省唐山市曹妃甸地区大气降尘矿物学特征进行了初步分析研究。结果表明,曹妃甸地区大气降尘粒径较粗,颗粒物包括块状、柱状、片状、球状及不规则粒状集合体,主要由石英、长石、石膏、云母、绿泥石、角闪石、白云石、方解石和赤铁矿等矿物组成;降尘样品中Cr、Cu、Zn、As、Cd、Pb等重金属元素含量均较高。研究分析表明,降尘样品中硅酸盐矿物主要源自地面扬尘,而石膏、方解石等碳酸盐矿物可能为环境中的次生矿物,样品中重金属污染主要来源于燃煤、工矿企业生产排放和少部分汽车尾气排放。     

我国产出的铀酰砷酸盐矿物及其环境矿物学意义

对我国产出的铀酰砷酸盐矿物的矿物学特征、形成环境和环境矿物学意义进行了较系统的综合论述。铀酰砷酸盐矿物是主要产出于铀矿床氧化带中比较特征的黄绿色表生矿物，是寻找原生铀矿床(体)的重要矿物学标志，化学组成主要是[AsO4]^3-和[UO2]^2 ，其中As和U均是对环境造成极大危害的有毒或放射性有害元素。As、U的地球化学性质十分活跃，在不同的酸、碱和氧化还原介质环境中的分解、迁移能力均很强，在矿床氧化带中的分解、迁移扩散会对矿区周围及其下游地区造成较大范围的严重环境污染。而在弱酸性至中性介质条件下，[AsO4]^3-和[UO2]^2 结合并与各种金属阳离子化合可形成相对稳定的铀酰砷酸盐矿物，由此可在一定程度上减少U、AS的迁移扩散及其对环境的危害。     

大气尘埃中矿物对人类健康影响的环境矿物学研究

大气尘埃中矿物微粒具有很强的化学活性,因为尘埃矿的的物质浓度和有害特征与环境互不相同,被人体吸入后会沉积,从而引起各种疾病,矿物致病的生物化学过程都发生在矿物表面或其附近,现代矿物学的研究方法和技术使得生物学家,病理学家,环境学家以及矿物学家得以共同努力以致力于这一新的跨学科领域的合作研究。     

钙稀土氟碳酸盐中四种B10S8新规则混层矿物的透射电镜研究

根据HRTEM研究，在四川西昌地区的钙稀土氟碳酸盐矿物衍生多晶体中发现了四种不同的B10S8型[即氟碳怖矿（B）／直氟碳钙铈矿（S）为10：8]新规则混层矿物（B10S8－I，B10S8－Ⅱ，B10S8-Ⅱ和B10S8－Ⅳ）。用SAED和HREM方法确定了四种新规则混层矿物的晶体结构对称性、晶胞参数、结构堆垛模式及晶体化学式等。四种B10S8新规则混层矿物结构中，Ce－F离子层的堆垛层序以及两个Ce－F离子层之间的碳酸根离子层的排列方式均不同。同时还观察到该类矿物中的畸结构及堆垛层错等。     

Further studies on torbanites and coorongite using transmission electron microscopy and C-isotope analysis

Transmission electron microscopy of torbanites from various localities in eastern Australia has revealed micro-organisms of possible methanogenic affinity. Botryococcus remains in the torbanites displayed close resemblance to the rubbery B. braunii accumulations deposited in recent bodies of freshwater origin. Compaction and collapse of structure seem to be the major visible alteration to the algal colonies. C-isotope compositions of the torbanites favour methanogenic activity. Comparison with recent botroyococcal accumulations support diagenetic alteration at a very early stage of deposition.     

Extrinsic and intrinsic mode of hydrogen occurrence in natural olivines: FTIR and TEM investigation

Olivine crystals from two mantle nodules in kimberlites (pipe Udachnaya and pipe Obnazennaya, Yakutiya, Siberia) were investigated using EMP, TEM, AEM and FTIR techniques to determine the mode of hydrogen occurrence in olivine. Olivine contains three types of nanometer-sized inclusions: “large” inclusions of hexagonal-like shape up to several hundred nm in size (1), lamellar defects (2) and small inclusions of hexagon-like shape up to several 10?nm in size (3). Lamellar defects and small inclusions are considered to be a “hydrous” olivine. All three types of inclusions contain OH^? or water, but they are different with respect to their phase composition. In “large” inclusions (1) hydrous magnesium silicates, such as serpentine?+?talc (“kerolite”?) and 10-Å phase?+?talc were identified. Lamellar defects (2) and small inclusions (3) are depleted in Mg and Fe compared to the olivine matrix, while the silica content is the same as that of olivine. Modulations in the periodicity of the olivine structure are observed in SAED patterns and HREM images of (2) and (3). The superperiodicity can be referred to OH^?-bearing point defect ordering in the olivine structure. If this is the case, the material of both lamellar defects and small inclusions can be assumed to be a “hydrous olivine” Mg_{2– x} v _x SiO₄H_{2 x} with a cation-deficient olivine crystal structure. Thus, both an extrinsic mode of hydrogen occurrence in olivine, such as nanometer-sized inclusions of OH^?-bearing magnesium silicates, and an intrinsic mode of hydrogen incorporation into the olivine structure, such as “hydrous olivine” in itself, were found. The data obtained here show that the OH absorption bands observed in olivine spectra at 3704(3717) and 3683(3688) cm^?1 can be unambiguously identified with serpentine; the band at 3677(3676) cm^?1 can be associated with talc. The absorption bands observed at 3591 and 3660?cm^?1 in olivine match those of the 10-Å phase at 3594, 3662 and 3666?cm^?1.     

矿物自动定量分析系统的基本原理及其在岩矿研究中的应用 ——以捷克泰思肯公司TIMA为例

近年来,矿物自动定量分析系统已广泛应用于地质、石油、矿业、冶金、考古和环境等领域,而中国对该系统在岩矿科研领域的应用则刚刚起步.文章以捷克泰思肯电镜公司(TESCAN)的全自动矿物分析系统TIMA(TESCAN Integrated Mineral Analyzer)为例,简述了该系统的基本原理、硬件和软件组成.TIM...     

凹凸棒石与酸反应纳米尺度研究——反应机理和表面积变化

利用高分辨透射电子显微镜(HRTEM)和BET-比表面积分析(BET-SSA)技术调查了沉积型凹凸棒石与酸作用过程中形态和比表面积变化,并探讨了凹凸棒石与酸反应机理。对不同条件下凹凸棒石与酸反应产物纳米尺度观察表明,凹凸棒石的酸溶反应既表现出棒状晶体端部四面体和八面体一致溶解,也表现出柱面位置四面体和八面体不一致溶解。纳米尺度观察揭示出凹凸棒石与酸反应机制是质子从外表面扩散渗透,而不是质子从晶体孔道的渗透,反应速率主要受穿过酸溶产物硅酸层扩散速率控制。凹凸棒石的酸溶反应过程中,酸处理凹凸棒石的纳米孔结构现象与柱面位置四面体硅局部溶蚀有关。酸处理凹凸棒石比表面积增加归因于凹凸棒石中八面体不均匀、不连续溶解和局部四面体硅的溶蚀导致凹凸棒石孔道开放和直径扩大,从而使N2分子更多的进入凹凸棒石的孔道。部分八面体残留对四面体片起支撑作用,当凹凸棒石中八面体阳离子近于完全溶解时,四面体片失去支撑,结构塌陷,内孔孔道消失,比表面积再度下降。     

Lower palaeozoic and precambrian petroleum source rocks and the coalification path of alginite

Organic-rich samples derived from a Middle Cambrian Formation in the Georgina Basin, and from the Middle Proterozoic of the McArthur Basin in northern and central Australia, yielded alginite ranging from immature oil shale material to overmature residue. A maturation scale has been developed based on the thermal evolution of alginite as determined from reflectance and fluorescence. The coalification path of alginite is marked by jumps in contrast to the linear path of wood-derived vitrinite. Six zones have been recognised, ranging from undermature (zone I), through the mature (zones II/III), followed by a stable stage of no change (zone IV) to the overmature (zones V and VI). The onset of oil generation in alginite as evident from the present study is at 0.3% R_{o Alg.} and is expressed in a change of fluorescence from yellow to brown, and a coalification jump from 0.3 to 0.6% R_o of Alg. In many boreholes zone III can be distinguished between 0.6 and 0.8% R_o of Alg. where subsequent oil generation occurs. Zones II and III represent the oil window.A zone of little or no change designated zone IV, at of alginite follows zones II/III. A marked coalification jump characterises zone V, where a pronounced change in reflectance occurs to >1.0% R_{o Alg.}, signifying peak gas generation. The border of oil preservation lies at the transition of zone V and VI, at 1.6% R_{o Alg.} In zone VI gas generation only occurs.Comparison of reflectance results with experimental and geochemical pyrolysis data supports high activation energies for hydrocarbon generation from alginite, and therefore a later onset of oil generation than other liptinite macerals (i.e. cutinite, exinite, resinite) as well as a narrow oil window.Transmission electron microscopy (TEM) confirms that alginite does not go through a distinct intermediate stage but that the percentage of unreacted organic matter decreases as maturation proceeds. A clear distinction can be made in TEM between immature alginite, alginite after oil generation, and alginite residue following gas generation. Alginite beyond 1.6% R_o acquires very high densities and the appearance of inertinite in TEM.Bitumens/pyrobitumens make a pronounced contribution to the organic matter throughout the basins and have been shown to effect pyrolysis results by suppressing T_max. The bitumens/pyrobitumens have been divided into four groups, based on their reflectance and morphology, which in turn appears to be an expression of their genetic history. Their significance is in aiding the understanding of the basins' thermal history, and the timing of oil and gas generation.     

Sediment particle size distribution and its environmental significance in Lake Erhai, Yunnan Province

A closed or semi-closed plateau lake, whose sediment records can provide us with plenty of fine and high resolution information, is a sensitive indicator of climatic and environmental changes. During the reconstruction of various short-time-scale climatic and environmental changes, the geochemical records in plateau-lake sediments are superior to other natural files. Based on fine dissection of the vertical profile of sediment particle sizes, this paper reveals the quasi-periodical changes of sediment particle sizes, which indicates the quasi-periodical fluctuations of the regional climate. A synthetic analysis of multiple indexes shows that sediment particle size is a more sensitive and more effective index of climatic and environmental changes than other geochemical indexes. High content of >20μm sediment particles and low content of 2–10μm sediment particles indicate a warm-dry climate and conversely a cold-humid climate, and their ratio can be used as an effective index of climatic changes. The basic climate succession in the region of Lake Erhai is characterized as being alternatively warm-dry and cold-humid and it has been developing into a warm-dry climate as a whole. There exist at least 2 time-scale quasi-periodical fluctuations of the regional climate in Lake Erhai. At present, the region of Lake Erhai is at the end of the warm-dry period and at the beginning of a cold-humid period, so the temperature will go down and the water level will rise. This project was supported by the National Natural Science Foundation of China (Nos. 49894170, 49773207).     

青藏高原气溶胶单颗粒类型及粒度分布

应用场发射扫描电镜(FESEM)对青藏高原纳木错综合观测站和香格里拉本底站2011年7～8月份不同天气情况下收集的气溶胶样品进行研究。结果表明,区域内气溶胶单颗粒类型主要包括烟尘集合体、球形颗粒(焦油球、燃煤飞灰)、似球形颗粒、矿物颗粒、生物颗粒等,香格里拉的球形颗粒中出现了飞灰颗粒,而纳木错样品中没有。纳木错气溶胶颗粒的数量-粒度峰值和体积-粒度峰值分别出现在0.2～0.3 μm和1～2.5 μm,矿物颗粒数量和体积最多,分别占44.4%和61.7%。香格里拉气溶胶颗粒的数量-粒度峰值和体积-粒度峰值都呈现双峰分布,主峰均分布在>2.5 μm范围,矿物颗粒数量和体积最多,分别占51.7%和58.7%。细粒子和粗粒子分别为纳木错和香格里拉气溶胶的主要类型。纳木错气溶胶中矿物颗粒最多,数量百分比为44.4%,其次为烟尘集合体(29.5%)和球形颗粒(26.1%),香格里拉气溶胶中矿物颗粒数量百分比为51.7%,其次为球形颗粒(29%)和烟尘集合体(19.3%);纳木错气溶胶总颗粒物主要分布在0.2～0.3 μm粒径范围中,数量百分比为32.59%,其中矿物颗粒最多(15%),其次为球形颗粒(11.5%)和烟尘集合体(6.1%)。香格里拉气溶胶颗粒物主要分布在>2.5 μm粒径范围中,数量百分比为37.5%,其中矿物颗粒最多(17.9%),其次为球形颗粒(10%)和烟尘集合体(9.6%)。     

Combining ECCI and FIB milling techniques to prepare site-specific TEM samples for crystal defect analysis of deformed minerals at high pressure

Dislocation microstructures in experimentally deformed single-crystal pyrope-rich garnet, (Mg,Fe)₃(Al,Cr)₃Si₃O₁₂, and polycrystalline forsterite, Mg₂SiO₄, were investigated by using electron channeling contrast imaging (ECCI) and transmission electron microscopy (TEM) combined with a focused ion beam (FIB)-microsampling. In the orientation-optimized ECCI method, we successfully observed individual dislocations across subgrain boundaries in a low-atomic-number mineral, pyrope-rich garnet (averaged Z-numbers, AZs ～ 10). Dislocations in a deformed forsterite (iron-free olivine) were also visible in the ECCI. In the ECCI on the single-crystal garnet, deformation bands consisting of dislocations, unusual contrasts in stripes and inhomogeneous distributions of sub-micrometer-sized pores were found. Further site-specific TEM observation on the deformation band revealed a high density of partial dislocations and stacking fault ribbons. The site-specific characterizations from ECCI to TEM, with assistance of FIB, can provide a new approach to investigate dislocation microstructures of deformed materials at high pressure and high temperature.     

N型氮化镓的结构和光电导特性

采用透射电镜高分辨反射电子衍射，扫描电镜形貌观察，X射线衍射等不同方法测试了不同Mg含量的N型氮化镓薄膜的结构。几种测定方法的比较表明，高分辨反射电子衍射是确定厚衬底的薄膜结构的快速而简便的方法，材料的杂质和缺陷是影响其光电导性质的重要因素。