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1.
煤是对温度和压力等地质因素十分敏感的有机岩,各种构造-热事件控制下的物理化学条件,是促进煤岩演化的根本动力。本文对煤变质作用过程的研究现状进行了综述,着重讨论了煤岩在高煤阶-石墨演化阶段的控制因素、演化过程和演化机制。煤变质作用包括煤化作用阶段和石墨化作用阶段,共同构成一个连续的有机质演化过程,总体趋势是分子结构有序化、化学成分单一化,最终演变为以碳元素为主、三维有序结构的石墨。温度和压力(应力)是控制煤变质作用两大因素,在不同的演化阶段,这两大因素所起的作用和演变机理都有所差异。在低、中煤阶演化阶段,温度是煤化学结构演化的主要控制因素,为化学键断裂提供活化能,应力缩聚和应力降解则对煤化学结构演化具有催化作用。高煤阶-石墨化阶段的主要机制是导致基本结构单元BSUs之间相互联结使短程有序化范围增大的拼叠作用,构造应力在其中起到关键作用,BSUs定向和面网间距不断减小,促进大分子物理结构演化。加强煤变质作用的高级阶段-石墨演化过程的研究,将丰富和深化对煤-石墨物理化学结构完整演化序列的认识。煤系石墨成矿机制的高温高压模拟实验,则为煤变质作用构造物理化学条件研究提供了可行的技术手段。 相似文献
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Traditional chemical methods have mainly focused on the variation and transportation of elements in the aquifer layer. The primary goal of this paper was to establish a spatial distribution model of chemical elements in the critical zone (CZ). The effects of anthropogenic activities (AA) and CZ structure on these models are quantitatively described. To this aim, 200 sediment and pore water samples were collected from ten drills in two profiles and analyzed for 16 variables. The most important influencing factors were identified from CZ structure parameters, and the effects of AA and CZ structure on chemical variables in the CZ were quantitatively characterized. Distribution models of the influences of AA and CZ structure were established for these two profiles. The correlation coefficient of the clay fraction content was greater than the other parameters, which was negative with total dissolved solids (TDS) and the arsenic of pore water and was positive with the arsenic in sediments. The distribution model of chemical variables was divided into three components: CZ1, CZ2, and A-A, which represent the effects of the first and second most important influencing factors and AA. The distribution models of chemical variables and their A-A part had the strongest similarity. The clay fraction content was more important than the other CZ structure parameters. It can inhibit the TDS and arsenic of pore water migration, resulting in greater arsenic ion adsorption on the sediment. AA is a triggering factor for chemical variables transportation, and CZ structure has an amplification effect on AA. According to characterize the spatial distribution of chemical variables in sediment and pore water within the CZ, the effects of AA and CZ structure can be quantitatively described, providing a rapid and effective technique for ecological environmental protection. 相似文献
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本文将龙女寺储卤构造深层地下卤水与不同浓缩阶段的黄海水两者的化学组分进行比较,以及对不同储卤层卤水之间的化学组分进行比较,结果表明该储卤构造地下卤水以高矿化度和富含Br,I,Sr,Ba等元素为特征,可分为两种类型,即碎屑岩储卤层的Cl NaCa型卤水和碳酸盐岩储卤层的Cl Na型卤水。前者来源于以陆相为主的同生沉积水,泥岩和页岩的隔膜渗滤作用可能对卤水化学组分的富集有着重要的影响;而后者则来源于海相同生沉积残余卤水,其化学组分主要受蒸发岩沉积的控制 相似文献
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The results of molecular composition modeling are presented for the well studied low-mass star-forming region TMC-1 and the massive star-forming region DR21(OH), which is poorly studied from a chemical point of view. The column densities of dozens of molecules, ranging from simple diatomic to complex organic molecules, are reproduced to within an order of magnitude using a one-dimensional model for the physical and chemical structure of these regions. The chemical ages of the regions are approximately 105 years in both cases. The main desorption mechanisms that are usually included in chemical models (photodesorption, thermal desorption, and cosmic-ray-induced desorption) do not provide sufficient gasphase abundances of molecules that are synthesized in surface reactions; however, this shortcoming can be removed by introducing small amount of reactive desorption into the model. It is possible to reproduce the properties of the TMC-1 chemical composition in a standard model, without requiring additional assumptions about an anomalous C/O ratio or the recent accretion of matter enriched with atomic carbon, as has been proposed by some researchers. 相似文献
6.
显微组分物理化学性质是影响煤炭清洁高效利用和煤储层物性的重要因素,已经认识到决定显微组分性质的根本原因在于其大分子结构。为了揭示显微组分大分子结构演化特征及其控制因素,从显微组分大分子化学结构与物理结构、大分子结构演化的构造应力效应、煤变质全阶段大分子结构演化特征等方面,总结了国内外研究进展,分析了存在的不足。指出由于富镜质组煤的广泛分布和重要工业用途使之成为煤结构研究的主要对象,惰质组的研究则相对缺乏,阻碍了对煤特性的全面认识。提出“煤变质作用的热-应力条件决定显微组分结构演化、惰质组与镜质组大分子结构演化具有差异性”的研究思路,采用惰质组/镜质组高温高压模拟和热模拟实验并与自然序列变质-变形煤对比,研究显微组分结构演化特征及其控制因素。定量刻画显微组分大分子结构与温压条件的关系,揭示构造应力对显微组分化学结构和纳米孔隙结构的控制,确定煤变质全过程中惰质组大分子结构的演化路径,建立惰质组大分子动力学模型。上述研究成果将充实对煤微观结构演化及其控制因素的全面认识,为煤炭清洁高效利用和煤储层物性评价提供基础依据。 相似文献
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水铁矿广泛分布于水、土壤、沉积物和生物体中,它具有大比表面积和高表面活性,控制和影响着环境中某些污染物质和营养元素的形态、迁移和转化。此外,它也是环境中其他晶质铁(氢)氧化物形成的前驱体。然而,人们对水铁矿在环境中的作用和重要性的认识还存在不足,主要表现在：(1)水铁矿通常被混淆为无定形铁氢氧化物或水合铁氧化物,环境中的水铁矿因难以分离和进行定量分析而使其含量常被低估;(2)水铁矿结晶弱,结构表征困难,对其在环境中的分布、组成、结构及性质的认识较欠缺。水铁矿以弱晶质的纳米颗粒形式存在,其XRD(X射线衍射)线少且宽、强度弱。根据衍射线的条数可将水铁矿分为结晶较弱的2 线水铁矿(2LFh)和结晶较好的6 线水铁矿(6LFh)。目前,普遍接受的水铁矿化学式为Fe5HO8·4H2O,但大量实验表明H2O不是水铁矿结构的必要成分,且容易被吸附的外来物质取代。有人提出水铁矿是一种二元结构,中心为八面体配位Fe,表面以四面体配位Fe为主,这有待论证。最近,通过PDF(配对分布函数)研究水铁矿的结构表明,理想水铁矿结构包含20%四面体配位Fe和80%八面体配位Fe,化学式为Fe10O14(OH)2。然而, 不少学者对这一新的水铁矿结构模型提出了质疑。对近年来水铁矿的分布、组成、结构和环境行为方面的研究和存在的问题进行了综述和讨论,并且对水铁矿的未来研究方向进行了展望。 相似文献
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涉及水土化学作用的研究,以往更多观注水土作用的极限状态—污染土等方面的研究,而忽略处在常态即常温、常压、缓变异的水化学环境中的城市区域土体稳定性研究,在这种环境中,影响土体稳定的要素—土体细观结构扮演着重要的角色,而其对诸如宏观现象—地面沉降、土洞的产生都有重要影响。理论与实践分析表明,在常态水环境下,土结构的破裂面并不是通过颗粒本身,而是通过颗粒、颗粒集合体与集合体之间粒间连接结。本文从易被忽略的化学作用角度、侧重分析水土作用中的化学作用、通过土细观结构这个桥梁进行水土化学相互作用分析,针对不同pH水环境下土的宏观变形过程进行试验,展示了土体宏观变形特性,试验证实土的细观结构是水土化学作用发生与发展的“平台”和主要场所。 相似文献
9.
新疆尉犁蛭石矿工业蛭石化学法膨胀的实验研究 总被引：1，自引：0，他引：1
在对采自新疆尉犁蛭石矿的工业蛭石样品进行化学成分和XRD分析研究基础上,选用工业级双氧水作为化学膨胀处理剂进行化学膨胀处理试验研究,结果表明:工业蛭石的化学膨胀特点和影响工业蛭石膨胀效果的主要因素是其晶层层间域中的过氧化氢分子在分解过程中所产生的氧气压力。对蛭石样品用不同浓度的双氧水作用相同的时间或用相同浓度的双氧水作用不同时间后发现:用浓度为25%的双氧水处理工业蛭石样品可以达到大于4倍的体积膨胀,膨胀后的工业蛭石样品的结构特征无明显变化,并能保持工业蛭石膨胀产物的韧性。 相似文献
10.
高温高压实验作为地球科学研究的重要方向之一,通过模拟地球深部的温度和压力条件,了解地球深部物质的物理化学性质、地球内部结构和动力学演化。角闪石属于双链硅酸盐矿物,为地幔岩石圈的重要组成,广泛分布在海洋地壳、俯冲板块、变质岩和火成岩中。作为俯冲带的重要含水矿物,角闪石的广泛分布和高温高压下的脱水对于理解俯冲带水含量以及水迁移具有重要作用,同时在俯冲带的地震活动、高电导率异常、地震波速异常和岩浆活动中扮演重要角色。在过去的近百年时间里,国内外学者对角闪石高温高压物理化学性质进行了大量的研究。角闪石具有非常复杂的元素组成和结构特征,由此也导致了不同角闪石物理化学性质存在显著不同,包括脱水与脱羟基反应中元素迁移的差异、角闪石形成与分解过程中碱性元素(K+Na)和H2O含量对热稳定的影响、不同空间群结构下的高压结构相变、原位条件下不同结晶方向的电导率异常、不同结晶学优选方位(CPO)下的波速异常等。已有的研究对于角闪石的物理化学性质以及其在俯冲带中发挥的作用有了比较清楚的认识,但仍然有许多问题需要进一步研究,如角闪石的高压脱水动力学、热物性和变形机制等。 相似文献
11.
A point-dipole calculation which incorporates an expression for the Lorentz-factor tensor has been used to model the effect of chemical substitution on refractive index and optic axial angle (2V). Isotropic electronic polarizabilities for the sodium D line are refined by least-squared methods from lattice dipole sums and observed refractive indices. Although the assumption of isotropic polarizability is unrealistic for many mineral structures, the model is useful in interpreting the relationship between structure, chemical composition, and optical properties. 相似文献
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Snežana S. Nenadović Ljiljana M. Kljajević Maja A. Nešić Marijana Ž. Petković Katarina V. Trivunac Vladimir B. Pavlović 《Environmental Earth Sciences》2017,76(2):79
The paper presents chemical and structural analysis of geopolymer materials which are obtained by alkali-activated calcined clay (metakaolin) originated from Serbia under strictly defined conditions. Characterization of the metakaolin and geopolymers molecular structure has been done using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The paper presents the possibility of obtaining geopolymer structure and differences in chemical and structural characterization of these materials taking into account the concentration of NaOH as a variable parameter. The results of MALDI analysis of metakaolin and synthesized geopolymer structures using various matrix system: 2,4,6 trihydroxyacetophenone (THAP), α-cyano-4-hydroxycinnamic, 2,6 dihydroxyacetophenone and laser desorption/ionization, have shown that THAP matrix is the most appropriate for analysing these aluminosilicate materials. 相似文献
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Structurally controlled, syn-rift, clastic depocentres are of economic interest as hydrocarbon reservoirs; understanding the structure of their bounding faults is of great relevance, e.g. in the assessment of fault-controlled hydrocarbon retention potential. Here we investigate the structure of the Dombjerg Fault Zone (Wollaston Forland, NE Greenland), a syn-rift border fault that juxtaposes syn-rift deep-water hanging-wall clastics against a footwall of crystalline basement. A series of discrete fault strands characterize the central fault zone, where discrete slip surfaces, fault rock assemblages and extreme fracturing are common. A chemical alteration zone (CAZ) of fault-related calcite cementation envelops the fault and places strong controls on the style of deformation, particularly in the hanging-wall. The hanging-wall damage zone includes faults, joints, veins and, outside the CAZ, disaggregation deformation bands. Footwall deformation includes faults, joints and veins. Our observations suggest that the CAZ formed during early-stage fault slip and imparted a mechanical control on later fault-related deformation. This study thus gives new insights to the structure of an exposed basin-bounding fault and highlights a spatiotemporal interplay between fault damage and chemical alteration, the latter of which is often underreported in fault studies. To better elucidate the structure, evolution and flow properties of faults (outcrop or subsurface), both fault damage and fault-related chemical alteration must be considered. 相似文献
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A. A. Marakushev 《Moscow University Geology Bulletin》2007,62(4):211-219
This paper shows that ferrous silicate meteorites (chondrites), which are conventionally regarded as direct condensates of the primordial solar nebula, are actually igneous and evolved in two stages that were contrasting in their physical and chemical parameters. The origin and early evolution of chondrites went on under enormous fluid pressure, which produced diamond embryos oversaturated with fluid inclusions, and gave rise to isotope abnormality and chondrite structure due to tear-shaped segregation of silicate melt in a Fe-rich diamond-bearing matrix melt. Chondrite crystallization mostly occurred during the second stage, which occurred under low pressure and was characterized by normal fractionation of isotopes and formation of structure opposite to chondrite (containing metal droplets in a silicate matrix), and which involved the formation of volcanic glass. 相似文献
15.
桃林闪锌矿的矿物学特征 总被引：3，自引：0，他引：3
本文研究了桃林铅锌矿闪锌矿的化学成分、晶胞参数、红外光谱及物理性质《比重、硬度和反射率)等方面的待征。讨论了成分、结构与物理性质之间的关系,并探讨了矿床成因。 相似文献
16.
增强煤层注水能力是目前需要亟待解决的问题,而煤层注水难易程度缺乏准确的判别标准。通过考虑煤体孔裂隙渗流分形结构特征和毛细作用下化学润湿特性,建立了煤层注水渗流量模型;基于概率论与数理统计方法基础,构建了集对联系度区间评价体系,划分了煤层注水的难易程度。结果显示：（1）注水效果受孔隙率、孔隙半径、接触角、液体的密度、表面张力、黏滞性系数、重力加速度等渗流结构参数和化学润湿特性等最简参数的影响,体系模型表征了煤体渗流结构和化学润湿特性与渗流量的关系。（2）在组合赋权下,孔隙率权重为0.32,对注水效果贡献较大,最大孔喉半径和接触角的贡献度次之;最小孔喉半径权重为0.17,对注水效果影响最小。（3）煤样X1、X2、X5评价指标值介于（0,0.25）,属于难注水煤层;煤样X3、X4评价指标值介于（0.25,0.50）,属于较难注水煤层。 相似文献
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V. A. Dement’ev 《Geochemistry International》2018,56(1):65-70
The minimal set of conditions is found under which a primitive genetic code can be formed in the chemical world in which polypeptides and polynucleotides can be produced. Molecular modeling demonstrates that multiple cycles of synthesis and thermal destruction of biopolymers result in spontaneous complication of their structure. This evolutionary progressive complication of polypeptides and polynucleotides coding them results in certain specific functions of the polypeptides, which are similar to properties of enzymes. Computer simulations confirm the internal logical consistency of the simplified scenario suggested for the origin of a genetic code as a process of transferring information on the structure of biomolecules to the historical future, in spite of the continuous thermal decomposition of these structures. 相似文献
19.
黔东南铝土矿含矿岩系镁铝铁结构及地球化学特征 总被引：1，自引：0，他引：1
黔东南铝土矿赋存于下二叠统梁山组,其含矿岩系具有沉积型铝土矿典型的"煤-铝-铁结构",即下部发育铝质页岩夹菱铁矿结核,中部由含铝岩组夹多层豆状或土状铝土矿组成,上部由碳质页岩、砂岩夹煤层组成。沉积环境为海陆交互相-滨海边缘沼泽相,具有稳定的构造背景。通过含矿岩系物质组成结构分析和元素地球化学研究认为:"煤-铝-铁结构"在铝土矿中的普遍出现,是沉积型铝土矿在矿化过程中物理化学环境多变导致的深度去硅去铁作用,加之外部环境提供充足的有机质物质来源,从而形成的非偶然结果。因此,含矿岩系的分层结构形成过程中的物理化学变化所导致的多种地质异常可作为找矿实践中的成矿标志。 相似文献
20.
针对火山岩储层,从岩石化学成分分类和岩石结构分类两个角度出发,提出了一种利用测井资料识别火山岩岩性的方法。基于取芯薄片鉴定资料获得对应井段的常规测井数据,利用统计学习理论中的支持向量机方法对其处理,得到地质上按岩石化学成分分类的火山岩岩性类别。建立地层微电阻率成像测井图像与不同结构火山岩岩性之间的对应关系,归纳出典型的微电阻率图像模式,从而得到地质上按岩石结构分类的火山岩岩性类别,结合上述两者结论确定最终岩性,实现了运用支持向量机算法处理常规测井资料与微电阻率图像模式相结合的火山岩岩性测井识别新方法。 相似文献