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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 2549-2551 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermal conductivity κ of an isotopically enriched (0.055% 13C) polycrystalline diamond plate made by chemical vapor deposition (CVD) has been measured for heat flowing in a direction either parallel (κ(parallel)) or perpendicular (κ⊥) to the plane of the plate. The room-temperature conductivities (κ(parallel)=21.8 and κ⊥=26 W cm−1 K−1) are higher than for any CVD diamond previously reported, and the κ⊥ value is higher than the best gem-quality single crystal with the natural abundance (1.1%) of 13C. Analysis of the temperature dependence of κ(parallel) reveals that the point-defect scattering of phonons is in fact significantly lower than expected for the natural abundance of 13C and that it is responsible for the improved conductivity. The observed anisotropy κ(parallel)/κ⊥=0.84 at room temperature is associated with the anisotropic grain structure.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 202 (1964), S. 581-583 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The recently developed technique of thermal analysis by high-temperature microscopy1 enables phase changes occurring during very swift temperature changes to be followed and characterized in terms of reaction temperature and associated rate of temperature change. The following are further examples ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 197 (1963), S. 683-684 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1. Cooling-rate to 1,320, 250/seo Fig. 2. Cooling-rate to 1,310. 325/seo Fig. 3. Cooling-rate to 1,220. 435c/sec Fig. 4. Cooling-rate to 1,220, 750/sec To achieve this the thermoelectric K.M.F. from tho thermocouple microfurnace is monitored during cooling by a cathode-ray oscilloscope. ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 225 (1970), S. 272-273 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Cements were prepared from a powder and liquid mixed in the ratio 4 g: 1 ml. The powder was a ground opal glass, a fluorine-containing alumino-silicate (percentage composition 187 Si: 150 Al; 63 Ca: 57 Na; 133 F; 10 P; 400 O) which was prepared by fusing quartz, alumina, fluorite, cryolite and ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 3 (1968), S. 47-60 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Phase behaviour over regions of the ternary system Na2O/B2O3/Nb2O5 has been explored. Liquidus temperatures and the stability regions of primary phases have been determined over selected composition ranges by high temperature microscopy. Crystallisation processes in melts and corresponding glasses have been followed using both conventional methods of thermal analysis and newly developed micro techniques combined with hot stage microscopy. An electron microscope has been employed to follow changes in the microstructure of quenched glasses after controlled heat treatments. It has been shown that the system contains a liquid immiscibility gap, and some attention is given in the discussions to the influence that can be assigned to cations in determining the extent of such gaps and general structural relationships in borate/oxide systems.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A study has been made of the crystallisation of glasses based on the eutectic between lithium metasilicate andΒ-eucryptite and of the rÔle of TiO2 in promoting fine-grained crystallisation. The hypothesis advanced in part 1 of this work is extended to a semi-quantitative measure of the effect of TiO2. Characteristics of two metastable phases are described in an appendix.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Agroforestry systems 38 (1997), S. 177-193 
    ISSN: 1572-9680
    Keywords: anthropology ; economics ; geography ; policy ; sociology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Fourteen years after the birth of the journal Agroforestry Systems, biophysical studies continue to dominate agroforestry research while other important areas have not received the attention they deserve. This paper reviews the progress in one of these under-researched areas, socioeconomics. A quantitative and qualitative analysis of published socioeconomic research papers and a survey of agroforestry socioeconomic researchers are used to evaluate the achievements in agroforestry socioeconomic research over the past 14 years: what are the major advances, gaps in knowledge, and constraints for closing those knowledge gaps? Although agroforestry socioeconomics remains a field in its infancy, both the scope and the quality of socioeconomic research are slowly improving. The recent trend away from literature reviews, qualitative, and purely descriptive quantitative research based on small sample sizes, and toward more rigorous statistical analyses of better and larger data sets is encouraging. Priority areas for future research include theoretical and empirical analyses of agroforestry adoption decisions, improved economic analyses, and policy studies at local, national, and regional levels.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The application of a recently developed micro differential thermal analyser (ΜDTA) to studies on the crystallisation of glasses is described. The technique permits continuous visual observation of microdroplets of melts and glasses during thermal analysis over a wide range of heating and cooling rates. Nucleation and crystallisation processes can be studied in conjunction with techniques of X-ray diffraction and electron microscopy. Crystal growth rates can be measured. Semiquantitative values for the heats of crystallisation of glasses can be obtained and kinetic data relating to the rate at which glasses undergo volume crystallisation can be derived from an analysis of the thermograms. The scope of the technique in linking structural information with the thermal and kinetic data associated with transformations in glasses is illustrated with data from three lithium aluminosilicate glasses.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1972), S. 220-238 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The chemistry of the cement-forming reaction between phosphoric acid solutions and fluorine-containing aluminosilicate glasses has been studied using a variety of physicochemical methods. These materials are the dental silicate cements and the microstructures of a number of these cements have been examined by optical, electron and scanning electron microscopy. The element distribution between partially reacted glass particles and the gel matrix which binds them has been determined by electron probe microanalysis. The chemical stability and variations in the mechanical strength between different cements is discussed in terms of a new hypothesis on the constitution of the gel matrix. Consideration is given to the possible strengthening role of microcrystallinity which has been shown by X-ray and electron diffraction to develop in the matrix. Attempts to strengthen the cement by incorporation of reinforcing agents is described.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Structural transformations have been studied in glasses related in composition to the binary eutectic between lithium metasilicate and β-spodumene. Crystallisation processes and changes in microstructure during the controlled heating of the glasses have been followed using X-ray diffraction, electron microscopy, high temperature microscopy, thermal analysis and electron spin resonance spectroscopy. The influence exerted by titanium dioxide on the phase relationships, crystal growth rates and micromorphology of the polycrystalline products of heat-treatment has been investigated and the findings used as a basis for proposals on the rôle of TiO2 during nucleation and crystal growth.
    Type of Medium: Electronic Resource
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