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基于麦夸特算法的X射线衍射物相定量分析的影响因素研究 总被引：2，自引：0，他引：2
X射线衍射物相定量分析方法很多,新近提出的麦夸特算法(Levenberg-Marquardt)在XRD物相定量分析中具有明显的优势,但在实际应用过程中,哪些因素会对该方法计算结果的准确度产生影响仍不清楚。为了指导实际操作过程并提高麦夸特算法在X射线衍射物相定量分析中的准确度和处理效率,本研究通过Matlab软件,将已知配比含量的刚玉、石英、方解石和钠长石与其计算值进行比较,探讨衍射峰强度、衍射峰背底、样品数量等因素对麦夸特算法应用于X射线衍射物相定量分析中计算结果的影响。结果表明:通过前三强峰法的计算结果比通过最强峰法的计算结果具有更高的准确度;由于物相晶体结构及衍射特性的差异,衍射峰背底对不同物相定量结果的影响程度各异,扣除背底后各物相计算结果的准确度整体上都有不同程度的提高;在利用麦夸特算法进行批量分析过程中,当样品数低于一定阈值时,样品数越多,计算结果的准确度提高越明显,但当计算的样品超过一定阈值时准确度不会有明显的提高。 相似文献
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为研究长江中下游红土剖面中粘土矿物的特征及其成因意义, 对安徽宣城红土剖面中粘土矿物进行深入、系统的X射线衍射分析.结果表明, 宣城剖面各土壤层中粘土矿物成分基本一致, 主要为蛭石、伊利石、高岭石, 以及粘土矿物过渡相. 由采自剖面上部样品的X射线衍射图可知, 经乙二醇饱和后7 ?衍射峰可分解为7.15、7.60和7.92 ?三部分, 表明除了高岭石(7.15 ?)外, 还存在高岭晶层含量分别为~80%和~95%的2种高岭-蒙脱石过渡相, 并以前者为主; 剖面下部样品在乙二醇饱和后, 7 ?衍射峰可分解为7.16、7.79和8.35 ?等3个衍射峰, 其中8.35 ?峰衍射强度很小, 表明除了高岭石外, 样品中存在高岭晶层含量为~90%和~43%的高岭-蒙脱石过渡相, 后者含量甚少.甲酰胺饱和结果表明, 高岭-蒙脱石混层粘土矿物相中高岭晶层为埃洛石相.加热试验的衍射图中10 ?衍射峰强度明显增强, 证实高岭相中含有一定数量的来源于绿泥石风化的蒙脱石间层; 而10 ?衍射峰的低角度一侧没有出现拖尾现象, 则指示高岭-蒙脱石混层矿物中的蒙脱石不是简单的羟基间层蒙脱石.此外, 红土剖面中还普遍出现过渡性粘土矿物伊利石-蒙脱石混层和伊利石-蛭石混层粘土矿物.大量过渡性粘土矿物相的出现, 从成土作用的角度上说明红土沉积物经历了沉积-风化、以及多期风化作用叠加, 而且在沉积-风化成土过程中, 气候环境变化于强烈化学风化的温暖、季节性干旱和强烈风化淋滤的温暖而更加潮湿的条件.蛭石-伊利石混层粘土矿物仅发育于红土剖面上部, 表明总体上剖面上部的化学风化程度低于剖面下部. 相似文献
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关于伊利石结晶度诸指数的评价 总被引：14，自引：1，他引：13
本文根据结晶学原理、Ｓｃｈｅｒｒｅｒ定律、Ｗａｒｒｅｎ－Ａｖｅｒｂａｃｈ理论和Ｘ射线衍射峰形态学原理提出任何衍射峰都是由五个基本要素组成的,即：衍射峰位置;最大衍射强度;半高宽;衍射峰形态和对称性。各衍射峰要素都具有其自身的物理学意义,其中,只有半高宽和衍射峰形态是与晶体内部结构和大小即结晶度相联系的。据此,分析评价了与Ｘ射线衍射相关的Ｋüｂｌｅｒ指数、Ｗｅｂｅｒ－ＤｕｎｏｙｅｒｄｅＳｅｇｏｎｚａｃ－Ｅｃｏｎｏｍｏｕ指数、Ｗｅａｖｅｒ指数、Ｍｉｌｉｅｒｓ指数、Ｗｅｂｅｒ指数、分解ＨＷ及纯Ｃ轴厚度等伊利石结晶度指数的理论基础、使用前提和条件、特点及误差源。指出Ｋüｂｌｅｒ指数、Ｗｅｂｅｒ－ＤｕｎｏｙｅｒｄｅＳｅｇｏｎｚａｃ－Ｅｃｏｎｏｍｏｕ指数和分解ＨＷ为非条件性单一结晶度指数;Ｗｅａｖｅｒ指数、Ｗｅｂｅｒ指数和高宽比为条件性单一结晶度指数;消除晶体内部微应变影响的ｃ轴厚度为全面描述伊利石结晶度指数;而Ｍｉｌｉｅｒｓ指数不可描述伊利石结晶度。 相似文献
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X射线衍射峰五基本要素的物理学意义与应用 总被引：6，自引：0，他引：6
本文根据Bragg衍射方程、Scherrer方程、衍射强度计算原理，研究讨论了X射线衍射5构成要素中的衍射峰位置、衍射峰宽度、衍射峰高度的物理学意义。根据实验研究证明了衍射峰不对称性的几何条件特征，并用地质事实验证了衍射形态变化与晶格应变和粒度大小的内在联系。从而阐明了单个衍射峰5基本构成要素的完整物理学意义，并以实例论证了5要素的实际应用价值。 相似文献
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钾含量对白云母X射线衍射特征的影响 总被引：5，自引：1，他引：4
对白云母X射线衍射峰强度的理论计算,发现其衍射峰的强度随钾含量呈规律性变化;对白云母活化释钾后不同钾含量样品进行X射线衍射实验,发现实测的衍射峰强度值与计算值变化趋势一致。计算与实测的白云母特征衍射峰强度比值曲线也有相同的变化趋势。这些结果表明白云母中钾含量是其X射线衍射特征变化的主要原因。 相似文献
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厌氧条件下,Cronobacter sakazakii以乙酸钠作为电子供体,针铁矿中Fe(Ⅲ)作为电子受体进行生命活动,其新陈代谢过程伴随Fe(Ⅲ)的还原。细菌增殖和稳定生长过程中不停还原针铁矿并大量累积Fe(Ⅱ);当细菌衰亡时,Fe(Ⅱ)的产生随之减缓;细菌的活动停止时,Fe(Ⅱ)不再积累并最终保持稳定。同步辐射XRD测试表明,微生物还原作用后针铁矿出现了一系列新衍射峰：4.8、6.03、6.13、6.84、7.7和11.4 峰,可能形成具层状结构的新物相。在XANES图谱中Fe主吸收峰向低能量方向移动1 eV,边前峰峰位中心向低能量方向移动且峰面积减小,表明Cronobacter sakazakii的异化Fe(Ⅲ)还原作用使针铁矿中Fe氧化态降低,矿物晶体结构发生了变化。 相似文献
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关于伊利石结晶度Kübler指数的误差计算 总被引：4，自引：0，他引：4
本文讨论了测量Kubler指数时产生的误差来源;提出以统计学方法描述“Strip型”衍射峰的半高宽度及其误差大小;以衍射强度、衍射峰形态与测量条件关系式描述“Digital型”衍射峰半高宽的测量误差大小。并特别提出了数字化衍射仪平滑操作产生的误差原理和总体趋势。提出的原理及公式,不仅适合半高宽的误差计算,也适合于其他衍射参数的分析计算,并可用于数字化光谱分析计算中。 相似文献
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广西陆川蛇纹石玉的岩相结构及成矿机理 总被引：3，自引：2，他引：1
应用外束质子激发X射线荧光光谱法、X射线衍射、激光拉曼光谱、扫描电子显微镜等无损分析技术,对广西陆川蛇纹石玉的成分、物相和结构进行分析。X射线衍射结果显示样品的衍射峰主要位于0.724、0.456、0.362、0.248、0.153和0.150 nm处,表明陆川蛇纹石玉主要矿物成分是蛇纹石,同时伴生方解石矿物与蛇纹石形成穿插交织结构。成矿机理分析表明,陆川蛇纹石玉是由白云质大理岩热液交代作用形成的,和广东的信宜玉均属于富镁碳酸盐型蛇纹石。拉曼光谱显示叶蛇纹石的特征峰位于229、376、457、686和1046 cm-1处,纤蛇纹石的特征峰位于228、345、386、624、690和1102 cm-1处,通过激光拉曼光谱可以快速区分陆川蛇纹石玉中纤蛇纹石和叶蛇纹石两种不同结构的蛇纹石亚种。 相似文献
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Tomoko Sato Hiroto Takada Takehiko Yagi Hirotada Gotou Taku Okada Daisuke Wakabayashi Nobumasa Funamori 《Physics and Chemistry of Minerals》2013,40(1):3-10
We have investigated the high-pressure behavior of cristobalite in helium by powder X-ray diffraction. Cristobalite transformed to a new phase at about 8 GPa. This phase is supposed to have a molar volume of about 30 % larger than cristobalite, suggesting the dissolution of helium atoms in its interstitial voids. On further compression, the new phase transformed to a different phase which showed an X-ray diffraction pattern similar to cristobalite X-I at about 21 GPa. On the other hand, when the new phase was decompressed, it transformed to another new phase at about 7 GPa, which is also supposed to have a molar volume of about 25 % larger than cristobalite. On further decompression, the second new phase transformed to cristobalite II at about 2 GPa. In contrast to cristobalite, quartz did not show anomalous behavior in helium. The behavior of cristobalite in helium was also consistent with that in other mediums up to about 8 GPa, where the volume of cristobalite became close to that of quartz. These results suggest that dissolution of helium may be controlled not only by the density (amount of voids) but also by the network structure of SiO4 tetrahedra (topology of voids). 相似文献
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随着琥珀市场需求的增加及琥珀优化处理技术的改进与创新,压制琥珀呈现外观逼真、结构复杂、方法多样的新态势。利用宝石显微镜、偏光显微镜、红外光谱仪对压制金珀、压制血珀、＂爆花＂压制琥珀、烤色压制琥珀、压固蓝珀、压固胶结蓝珀、压制蜜蜡等样品的宝石学参数、显微结构、红外吸收光谱进行了研究与分析,结果显示,碎粒-碎粉结构、红色斑点结构、不含＂血丝＂状构造的粒状＂镶嵌＂结构、碎块胶结结构等是压制琥珀的结构鉴定特征;颗粒间分布的＂太阳光芒＂、紊乱流纹、叶脉状流纹、丝瓜瓤状流纹等是压制琥珀的内含物鉴定特征;若蓝珀中的红外光谱I=2 932cm-1/I=1 723cm-1处的吸收强度比值接近1∶1,暗示着该蓝珀可能经过了优化处理。 相似文献
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R. PALMERI M. L. FREZZOTTI G. GODARD R. J. DAVIES 《Journal of Metamorphic Geology》2009,27(9):685-705
Monocrystalline quartz inclusions in garnet and omphacite from various eclogite samples from the Lanterman Range (Northern Victoria Land, Antarctica) have been investigated by cathodoluminescence (CL), Raman spectroscopy and imaging, and in situ X‐ray (XR) microdiffraction using the synchrotron. A few inclusions, with a clear‐to‐opalescent lustre, show ‘anomalous’ Raman spectra characterized by weak α‐quartz modes, the broadening of the main α‐quartz peak at 465 cm?1, and additional vibrations at 480–485, 520–523 and 608 cm?1. CL and Raman imaging indicate that this ‘anomalous’α‐quartz occurs as relicts within ordinary α‐quartz, and that it was preserved in the internal parts of small quartz inclusions. XR diffraction circular patterns display irregular and broad α‐quartz spots, some of which show an anomalous d‐spacing tightening of ～2%. They also show some very weak, hazy clouds that have d‐spacing compatible with coesite but not with α‐quartz. Raman spectrometry and XR microdiffraction characterize the anomalies with respect to α‐quartz as (i) a pressure‐induced disordering and incipient amorphization, mainly revealed by the 480–485 and 608‐cm?1 Raman bands, together with (ii) a lattice densification, evidenced by d‐spacing tightening; (iii) the cryptic development of coesite, 520–523 cm?1 being the main Raman peak of coesite and (iv) Brazil micro‐twinning. This ‘anomalous’α‐quartz represents the first example of pressure‐induced incipient amorphization of a metastable phase in a crustal rock. This issue is really surprising because pressure‐induced amorphization of metastable α‐quartz, observed in impactites and known to occur between 15 and 32 GPa during ultrahigh‐pressure (UHP) experiments at room temperature, is in principle irrelevant under normal geological P–T conditions. A shock (due to a seism?) or a local overpressure at the inclusion scale (due to expansion mismatch between quartz and its host mineral) seem the only geological mechanisms that can produce such incipient amorphization in crustal rocks. This discovery throws new light on the modality of the quartz‐coesite transition and on the pressure regimes (non‐lithostatic v. lithostatic) during high‐pressure/UHP metamorphism. In particular, incipient amorphization of quartz could favour the quartz‐coesite transition, or allow the growth of metastable coesite, as already experimentally observed. 相似文献
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Selective extraction procedures applied to geochemical prospecting in an area contaminated by old mine workings 总被引：1，自引：0，他引：1
F. Sondag 《Journal of Geochemical Exploration》1981,15(1-3)
A geochemical soil survey in the vicinity of the known ore body at Lontzen (Belgium) revealed numerous lead and/or zinc anomalies. Three soil traverses were selected in this area and examined for possible contamination. Two anomalous samples from one traverse were obviously contaminated (brick fragments). A sequential selective extraction procedure was applied to the soil samples, using a modification of the method of Gatehouse et al.Using this procedure, lead anomalies related to the probable extension of a known galena-sphalerite vein appear in every dissolution step. In contrast, in contaminated samples, only the final acid digestion produced anomalous values. One may thus suppose that contamination of the sample adds metal in the form of a resistant phase which is only dissolved by strong acid reagents. It should be noted that the contrast between anomalous and background values is highest for hydroxylamine hydrochloride and about the same for all other dissolution steps.The samples were also submitted to non-sequential selective extractions. The calculation of the difference between non-sequential and sequential extractions leads to the localization of two highly contrasted peaks which correspond exactly with the ore veins. 相似文献
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Carlo Bertok Luca Martire Elena Perotti Anna d’Atri Fabrizio Piana 《Swiss Journal of Geoscience》2011,104(2):237-255
The Middle–Upper Jurassic succession of the Marguareis–Mongioie area (Ligurian Briançonnais Domain), developed in a protected shelf environment evolving into a pelagic plateau, bears clear evidence of synsedimentary tectonics such as: growth fault-related structures; neptunian dykes; marked lateral variations in stratigraphic thicknesses testifying to the juxtaposition of sectors characterized by different sedimentation and subsidence rates; discordant, anomalous stratigraphic contacts corresponding to paleoescarpments; nodular beds showing evidence of fluidification interpreted as seismites; and the occurrence of sand-sized quartz grains pointing to denudation of Permo-Triassic quartz-rich rocks. Such evidence documents an important Middle-Late Jurassic post-breakup tectonic activity, which was more effective in controlling the basin topography than the Early Jurassic syn-rift tectonic phase. Two main tectono-sedimentary stages, one occurring during the Bathonian, the other falling within the Callovian–Kimmeridgian interval, were reconstructed. The first stage can be referred to a fault-related activity occurring shortly after the initial stages of oceanic spreading of the Ligurian Tethys; the second can be genetically related to the far effects of the first rifting stage of the Bay of Biscay and the Valais basin. 相似文献
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G.R. Parslow 《Journal of Geochemical Exploration》1981,15(1-3)
In geochemical surveys, including those of lake sediments, it is convenient to classify logarithmic cumulative frequency distributions of elements as anomalous, background, or intermediate. The third, and commonest, group presents the dilemma - Is a given distribution in that group tending towards an anomalous or a background distribution? Data from a series of surveys suggest that the relationship of loss on ignition to metal tenor can be used as an indicator of an element's “potential” or “availability” in the region of the survey. In turn, increased availability implies an anomalous source, such as an ore deposit. Areas with the best potential are considered to be those where logarithmic cumulative distributions of particular elements have the same or greater positive slopes than the associated loss on ignition distribution. The method does not define areas within the survey that can be considered more anomalous, only whether or not the given survey area exhibits a greater than expected concentration of a given element. 相似文献
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新型热压WC-Fe基金刚石钻头钻进试验 总被引：1，自引：0，他引：1
为满足硬岩钻探的需要,将传统的热压碳化钨(WC)基金刚石钻头胎体中一部分WC用Fe代替,用Excel中的回归分析和非线性规划求解计算出的最优胎体配方,试制了新型热压WC-Fe基金刚石钻头,在可钻性为8级以上的岩石上进行了室内、外钻进试验,取得了较好的效果。 相似文献