Nature of interstratified kaolin-smectites in some Australian soils

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 805 ◽  
Author(s):  
GJ Churchman ◽  
PG Slade ◽  
PG Self ◽  
LJ Janik
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Clay Minerals ◽  
X Ray Diffraction ◽  
Size Fractions ◽  
X Ray ◽  
Transmission Electron ◽  
Different Types ◽  
Interstratified Phase

The clay minerals in the < 2 �m, and finer, size fractions of several horizons from each of five Australian soils of different types and from different locations have been analysed by X-ray diffraction, infrared spectroscopy, transmission electron microscopy and X-ray fluorescence. Samples from each profile contained a phase in which layers of smectite and of kaolin (positively identified as kaolinite) were randomly interstratified with each other. The relative proportions of the two types of layers varied widely. One interstratified phase contained 70% smectite. This value for smectite content of kaolin-smectites is as high as any reported in the literature. The charges associated with the interstratified smectite layers also differed substantially. Discrete kaolinite commonly occurred along with interstratified kaolinite-smectite, Towards the surfaces of the soils, the proportions of kaolinite in the interstratified phases increased at the expense of smectite.

Mineralogical and cathodoluminescence characteristics of Ca-rich kutnohorite from the Úrkút Mn-carbonate mineralization, Hungary

2007 ◽  
Vol 71 (5) ◽  
pp. 493-508 ◽  
Author(s):  
M. Polgári ◽  
B. Bajnóczi ◽  
V. Kovács Kis ◽  
J. Götze ◽  
G. Dobosi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Electron Microprobe ◽  
The Self ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Bright Orange ◽  
Single Emission

AbstractKutnohorite with moderate and bright orange-red cathodoluminescence (CL) was studied by CL microscopy and spectroscopy. This mineral was found in fossiliferous concretions composed mainly of rhodochrosite from the Mn-carbonate mineralization at Úrkút, Hungary. The CL microscopy reveals that kutnohorite occurs as impregnations, layers and veinlets. X-ray diffraction, infrared spectroscopy and electron microprobe studies indicate that the luminescent kutnohorite has excess Ca (72.9–80.0 mol.% CaCO3, 16.3–20.5 mol.% MnCO3, 3.3–5.6 mol.% MgCO3 and 0.0–0.5 mol.% FeCO3). Transmission electron microscopy shows that the luminescent carbonate has a dolomite-type structure, with modulated and mosaic microstructures. The CL spectra of this Ca-rich kutnohorite have a single emission band at 630 nm that is characteristic of Mn2+substitution in the structure. Our results provide evidence for moderate-to-bright cathodoluminescence of Mn-rich natural carbonates even at 8–10 wt.% Mn and up to 2400 ppm Fe. The self-quenching of Mn appears incomplete in the case of Ca-rich kutnohorite from Úrkút.

Synthesis and photocatalytic hydrogen evolution of meso-tetrakis(p-sulfonatophenyl)porphyrin functionalized platinum nanocomposites

2010 ◽  
Vol 14 (06) ◽  
pp. 540-546 ◽  
Author(s):  
Lingling Zhang ◽  
Yongtao Lu ◽  
Yukou Du ◽  
Ping Yang ◽  
Xiaomei Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Antenna System ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Visible Absorption Spectroscopy

Meso-tetrakis(p-sulfonatophenyl)porphyrin (TPPS4) functionalized platinum nanocomposites were synthesized and characterized using ultraviolet-visible absorption spectroscopy (UV-vis), fluorescence spectroscopy (FL), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD) methods. The postulated configuration of TPPS4 functionalized platinum nanocomposite may be described as an antenna system containing a photoreceptive TPPS4 shell and a nanosize platinum core. Fluorescence and photoelectrochemistry studies of both TPPS4 and the platinum nanocomposites showed that efficient electron/energy transfer occurred from the TPPS4 donor to the metallic nanocore acceptor. TPPS4 functionalized platinum nanocomposites are photocatalytic active for water reduction to produce hydrogen. The turnover numbers (TONPt and TONTPPS4) and quantum yield of hydrogen (ϕH2) for the photocatalyst (nPt:nTPPS4= 250) were 44, 11056, and 1.8%, respectively, calculated on the basis of the total amount of H2 evolution for 12 h irradiation.

Structure of UMoO5 studied by single-crystal X-ray diffraction and high-resolution transmission electron microscopy

1996 ◽  
Vol 52 (6) ◽  
pp. 961-965 ◽  
Author(s):  
O. G. D'yachenko ◽  
V. V. Tabachenko ◽  
R. Tali ◽  
L. M. Kovba ◽  
B.-O. Marinder ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slight Excess ◽  
Transmission Electron ◽  
Different Types

A combination of X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) has been used to study the crystal structure of molybdenum uranium pentoxide, UMoO5, obtained by hydrothermal and ceramic methods. Crystal data: Mr = 414.0, orthorhombic, Pbaa (number 54), a = 12.746 (1), b = 7.3494 (7), c = 4.1252 (2) Å, V = 386.4 (1) Å3, Z = 4, Dx = 7.116 Mg m−3, R = 0.037 for 723 reflections. The structure of UMoO5 is related to that of UVO5. Both are built up by slabs of pentagonal UO7 bipyramids with slabs of MO6 octahedra in-between. They differ in symmetry due to different types of displacement of the M atoms from the ab plane. The HRTEM study revealed a few defect regions in the UMoO5 crystals prepared by ceramic methods. Energy-dispersive spectroscopy (EDS) analyses indicate a slight excess of uranium in such crystals. Hypothetical models of defect regions are given.

Preparation of Hydroxyapatite-Fibroin Nanocomposites

2005 ◽  
Vol 288-289 ◽  
pp. 191-194 ◽  
Author(s):  
X.D. Kong ◽  
Xue Min Wang ◽  
X. Yu ◽  
Fu Zhai Cui
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
X Ray Diffraction ◽  
Mineralization Process ◽  
Initial Concentration ◽  
X Ray ◽  
Transmission Electron ◽  
Fibroin Solution

Nanocomposites of hydroxyapatite-fibroin (HA-FB) were prepared using the biomimetic process. The Nanocomposites were detected with X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The FTIR results showed that chemical bond forms between HA nanocrystals and fibroin protein. The secondary structure of fibroin can be affected by the mineralization process. TGA results indicated the content of mineralized fibroin in the nanocomposites can be freely adjusted by changing the initial concentration of fibroin solution. TEM image showed that the diameter of the single mineralized nanofibrils is about 2-3 nm and the nanofibrils can aggregate into bundles with the size of 6-8 nm in width and 30-60 nm in length.

Identification of pseudoboehmite in mixtures with phyllosilicates

Clay Minerals ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 351-359 ◽  
Author(s):  
A. Violante ◽  
P. M. Huang
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Detection Limit ◽  
Clay Minerals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Oriented Samples

AbstractThe influence of kaolinite and montmorillonite on the identification of pseudoboehmite was studied by X-ray diffraction (XRD), differential thermal analysis (DTA), infrared absorption (IR), and transmission electron microscopy (TEM). In the randomly oriented samples containing different proportions of the clay minerals and pseudoboehmite, pseudoboehmite was not easily detectable by XRD even in a sample containing 40% of pseudoboehmite. Preheating of the samples at 110-300°C improved the detection limit to 30%. In samples obtained by mixing suitable amounts of the suspensions of the clay minerals (<2μm)and pseudoboehmite, the identification of pseudoboehmite was even more difficult. In oriented samples, pseudoboehmite was detectable only when present in amounts >30%, at low full-scale counts per second (1000-400 cps), on preheated samples in the presence of kaolinite, or on the samples that were Mg-saturated and solvated with ethylene glycol in the presence of montmorillonite. Identification of pseudoboehmite in the presence of kaolinite or montmorillonite by DTA, IR or TEM failed, even in samples containing 50% pseudoboehmite. In the presence of both kaolinite and montmorillonite (1:1 w/w), the identification of pseudoboehmite became much more difficult than in the presence of either mineral alone. The presence of pseudoboehmite in soils may, thus, be undetectable by standard clay mineralogical analyses.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

Multi-scale Investigation of Heterogeneous Swift Heavy Ion Tracks in Stannate Pyrochlore

2021 ◽  
Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Multi Scale ◽  
Ion Tracks ◽  
Swift Heavy Ion ◽  
Transmission Electron

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

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