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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 12 (1983), S. 42-46 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The usual method of polishing the surface of a solid sample for examination using the x-ray microprobe technique cannot be adopted for clay minerals. A modified method is suggested and its validity is tested using vermiculite mineral. It is observed that precision of quantitative elemental analysis increases significantly according to the present pretreatment procedure; variation from values obtained by wet chemical method is 〈 1% for SiO2, MgO and Fe2O3 and 2-3% for the rest. However, values obtained with the x-ray microprobe technique vary enormously from point to point and this non-uniformity is explained in terms of the structural characteristics of the clay mineral. The variation increases with the rise in temperature of treatment due to structural modifications occurring during heat treatment. The x-ray microprobe technique has been found to be quite effective in determination of trace elements such as K and Ti.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 17 (1988), S. 181-185 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Pyrophyllite was heat treated up to 1000°C in the presence of fluxes such as Li2CO3, Na2CO3, K2CO3 and CaCO3 and the products were examined by scanning electron microscopy (SEM). It is shown that the surface morphology of the mineral varies with both temperature and flux. The dehydroxylation reaction in the mineral commences at 500°C and continues above 900°C. Dehydroxylated phases are observed even at 950-1000°C. The formation of free Al2O3, cristobalite, mullite and other phases from pyrophyllite was detected by the SEM examination.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 18 (1989), S. 15-18 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: SEM micrographs showing porous structures and bonding of pores through broken mica flakes are presented. Pores of varying dimensions (10-400 μm) are formed. Interlayer spaces in mica are shown to be the preferential direction for heat and subsequently crack propagation during heat treatment for producing cellular insulating bricks at 900°C. The cracks end up with the formation of large pores in the presence of foaming agent and sodium silicate.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 18 (1989), S. 215-218 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The surface structure of silicon carbide whiskers, produced from rice husk at 1500-1800°C, was examined by x-ray photoelectron spectroscopy. An ESCA survey scan of the surface showed Si, C, O and F to be present; Si in the form of SiCx and SiOx and C in the form of SiCx and CHx. On sputtering the sample, the SiOx and CHx species were reduced and the SiCx level increased. The photoelectron spectra are presented.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 18 (1989), S. 219-224 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The structural characterization of alumina fibres obtained from an aluminium salt and three natural fibres (jute, sisal and coir) was examined by EDXRF and XRD. Elemental composition spectra from EDXRF of fibres pyrolysed at 1200 and 1400°C are presented and the results are compared with those obtained by wet chemical analysis and atomic absorption spectrometry. XRD diffractograms of the same samples are also shown. The evolution of the α phase of alumina with increase in pyrolysis temperature was examined. Scanning electron micrographs of alumina fibre with jute fibre are also presented.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 10 (1981), S. 82-84 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Various pretreatments required for analysis of vermiculite minerals by scanning electron miscroscopy are described. It is shown that lyophilized samples exhibit more characteristic and reproducible micrographs than when simply dried in air. The mineral should e preheated in vacuum at 150°C to aviod the risk of exfoliation. In view of the fragile structure of clay minerals, polishing of the solid is to be avioded.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 18 (1989), S. 267-269 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Rice husk was heat treated up to 1300°C and the products were examined by scanning electron microscopy. The fibrous structure of the initial rice husk persisted throughout. Cristobalite and tridymite were detected in the product at 1250°C by x-ray diffraction. The fibrous structures were characterized and shown to have a bearing on the formation of SiC whiskers as substrates.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 11 (1982), S. 64-65 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Finely divided metal particles, formed in the interlayer space of montmorillonite, have been identified by a x-ray microprobe technique and their dimensions measured by scanning electron microscopy. The dimensions of Ni0 and Cu0 obtained on reduction of the respective metal ions by H2 have been shown to be ∼ 100 Å.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 16 (1987), S. 57-60 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The Silica structural framework in plant materials can be separated from the organic part by acid leaching and can be examined by SEM. Scanning electron micrographs characterizing the bonding and distribution patterns of silica in rice husk, rice straw and sugarcane leaves are presented. The differences in the surface morphology of the three plant products are discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 14 (1983), S. 406-409 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectra of Mg(ClO4)2·6H2O and Zn(ClO4)2·6H2O single crystals have been recorded in the region 4000-20 cm-1 using an Ar+ laser as a source of excitation. The polarization behaviour of the Raman lines under different crystal orientations is reported. It is shown that the water molecules lie almost in a plane perpendicular to the crystal c-axis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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