钙稀土氟碳酸盐矿物中新多型体的HREM研究

利用高分辨电子显微术（ＨＲＥＭ）研究了钙稀土氟碳酸盐矿物系列中氟碳铈矿（Ｂ）／直氟碳钙铈矿（Ｓ）的混层结构。发现并确定了Ｂ＿５Ｓ＿２（ＩＨ，３Ｒ）、Ｂ＿５Ｓ＿４（３Ｒ，６Ｒ）和Ｂ＿（１８）Ｓ＿（１０）（ＩＨ）规则混层矿物中５种新多型的晶体结构类型、晶胞参数以及理论晶体化学式等。ＨＲＥＭ研究揭示出，在Ｂ＿ｍＳ＿ｎ（ｍ＞ｎ）型规则混层矿物新多型体的结晶过程中，成矿地质环境是复杂的。阐明了这些多型体是由该系列矿物中的氟碳铈矿（Ｂ）和直氟碳钙铈矿（Ｓ）结构单元层以不同比例沿ｃ轴方向的有序堆垛构成。     

腐植煤中的超细纹层

利用超薄切片透射电镜分析技术，在华北东部太原组和山西组、吐─哈盆地侏罗系腐植煤中检出了超细纹层。超细纹层在腐植煤中呈分散状、间隔状和密集状，前二者主要存在于无结构镜质体中，后者则存在于沥青质体或层状藻类体条带中。超细纹层来源于微藻类细胞的抗分解外壁，是藻类在超微层次的重要表现形式。腐植煤形成过程中藻类的贡献较藻类体数量所反映的要高。     

A preliminary scanning electron microscope study of honeycomb weathering of sandstone in a coastal environment

Honeycomb weathering has been observed in a Carboniferous sandstone at a coastal location near Ballycastle on the north coast of Northern Ireland. Specimens of this sandstone have been analysed by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Results reveal that calcium sulphate (gypsum) is the only salt present and is found only at and immediately below the rock surface. SEM observations suggest that crystallization of salts in pores could easily dislodge quartz grains to promote granular disintegration, whilst etching of quartz grain surfaces attests to chemical weathering activity within the rock However, the reason for the development of the honeycomb pattern is not known.     

扫描电镜的定量体视测量法

本文提出了一种新的体视学原理及其在扫描电子显微镜中的应用。借助于它的实验技术,可从图象中获得大量信息,而且能测定图片上任何物体的真实尺寸与几何图形,这种方法具有如下的新功能:1.可测定小晶面夹角;2.可测定图片上任意两点之间的真实距离;3.可测定曲线的长度和曲面的面积。文中例举了该法应用于地学的三例.     

Molecular weight distribution,analytical and spectroscopic characterization of humic fractions sequentially isolated by organic solvents from a brown coal humic acid

A sequential fractionation procedure employing a series of selected mild organic solvents of different polarity has been applied for the isolation of chemically different organic fractions from a brown coal humic acid. Elemental composition, molecular weight distribution, i.r. and electron spin resonance analysis were carried out on the isolated humic fractions. They were characterized by: (a) a low polydispersity, (b) a decreasing aliphatic and increasing aromatic character along the series, (c) very different molecular weight which significantly correlated with E₄/E₆ ratios (particle aggregation and molecular association) and free radical concentrations (chemical and biochemical activity). Significant correlations were found between physico-chemical parameters of the isolated humic fractions, i.e. M_n, M_w, E₄/E₆ ratios, spins/g contents and the dielectric constants of the solvents used. This suggested the efficiency of the applied procedure in isolating chemically different organic fractions from the bulk, original humic acid.     

Slope process change and colluvium deposition in Swaziland: An SEM analysis

Electron microscope analysis of sixty samples taken from six colluvium sites in Swaziland has shown that the quartz grains exhibit marked edge abrasion in the uppermost beds of exposures. This edge abrasion is lacking in the lower beds in all sections examined and indicates slope process change during colluvium deposition. A model of slope evolution is provided, in which slope erosion progressively brings about more channelling and causes greater surface roughness because of the exhumation of more core stones and differentially weathered rock. This roughness causes increased edge abrasion.     

衍射指标h和k的互换问题

通过衍射线指标和面网指标的联系讨论了晶体的对称性对衍射指标h和k互换的影响。在下列情况下衍射指标h和k是不能互换的:在低级晶族;在四方晶系C_(4h)—4/m劳厄点群,六方品系C_(6h)—6/m劳厄点群和立方晶系T_h—m3劳厄点群对于hko和kkl型衍射;在三方晶系选取六方晶胞的情况下,在C_(3i)—3劳厄点群对于hol,okl,hko和hkl型衍射,在D_(3d)—3m劳厄点群对于holokl和hkl型衍射,以及在菱面体点阵除非h和k都是三的倍数。     

沉积岩中蒙脱石-伊利石混层矿物的SEM/EDAX分析

本文利用扫描电子显微镜与X射线能量色散分析联合法,对沉积岩中蒙脱石-伊利石混层矿物进行系统微区成分分析,求出混合层中伊利石的百分含量。     

合成斜方辉石系列的红外光谱研究

在30kbar和900℃条件下,用等化学计量氧化物混合物合成了11个斜方辉石系列的样品,并对合成的样品进行了X射线粉晶分析和红外光谱分析。分析结果表明,晶胞参数和红外光谱随化学成分的改变而产生复杂的变化。不仅晶胞参数b和M而且频率ν_(670cm)-1和M之间存在很好的线性相关关系,通过用最小二乘法所拟合的相关方程可容易地测定斜方辉石的成分,但是α和c与M之间只有较差的线性关系,而ν_(450cm)-1和M以及ν_(380cm)-1和M之间并无简单的线性相关关系,这可归因于Fe~(2+)在M_1和M_2位置的有序分布。     

Limestone weathering in Eastern Australia. Part 2: Surface micromorphology study

Results from long term microerosion meter (MEM) studies indicate that microenvironments are characterized by different erosion rates. A complementary study, carried out on the same sites, examines the microscale morphology in each environment. Optical and scanning electron microscopy were used to identify a range of features thought to reflect different processes. Under subaerial conditions micromorphology is dominated by biological weathering features owing to the presence of microflora. Sites permanently covered by soil or stream water have only dissolution etch features, though stream sites may exhibit microfractures. Sites with periodic exposure exhibit both dissolution and biological etch features. The natural environment is more accurately reflected by allowing some microflora colonization of MEM sites rather than preventing colonization by artificial means.