Results 251 to 260 of about 3,360 (286)

Mechanochemical Transformations in the Zinc-Magnetite System

Hyperfine Interactions, 1998
Mixtures of magnetite and zinc powders were milled for up to 540 minutes and the development of the system was followed using X-ray diffraction, Mossbauer spectroscopy, and magnetic measurements. The process takes place in two overlapping steps. During the first hour of milling, a nonmagnetic intermediate mixed oxide phase forms which decomposes into ...
L. Takacs, Robert C. Reno, Martha Pardavi-Horvath   +2 more
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Mechanochemical Transformations in α-Fe2O3 – ICEMS Study

Hyperfine Interactions, 2002
Integral conversion electron Mossbauer spectroscopy has been used to investigate the phases and transformations which occur when α-Fe2O3 is wet-milled in vacuum for up to 144 h. In addition to the transformation to off-stoichiometric Fe3−xO4 observed previously by transmission Mossbauer spectroscopy, the room temperature ICEMS spectra reveal the ...
S. J. Campbell, G. KlingelhÖfer, W. A. Kaczmarek, M. Hofmann, R. Nagel, G. Wang   +5 more
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Mechanochemical transformations of natural gas hydrates

Petroleum Chemistry, 2009
Chemical transformations of hydrates of natural gas from the Irelyakh gas and oil field of the Republic of Sakha (Yakutia) upon vigorous mechanical treatment were studied. It was found that a general feature of mechanochemical transformations of natural gas hydrates is an increase in the carbon chain length of hydrocarbons forming the hydrates.
L. P. Kalacheva, E. Yu. Shits, A. F. Fedorova   +2 more
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Mechanochemical transformations in NaNH2-MgH2 mixtures

Journal of Alloys and Compounds, 2012
Abstract Mechanochemical transformations occurring during ball milling of sodium amide (NaNH 2 ) with magnesium hydride (MgH 2 ) taken in 2:3 and 2:1 molar ratios have been investigated using X-ray powder diffraction (XRD) and solid-state nuclear magnetic resonance (SSNMR) techniques.
Niraj K. Singh, Takeshi Kobayashi, Oleksandr Dolotko, Jerzy W. Wiench, Marek Pruski, Vitalij K. Pecharsky   +5 more
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Study of a mechanochemical transformation in iron pyrite

Journal of Alloys and Compounds, 2000
The observation of a phase transformation from pyrite FeS2 (Fe2+ in a low-spin state) to szomolnokite FeSO4·H2O (Fe2+ in a high-spin state) by the mechanical action of ball-milling in air is reported. 57Fe Mossbauer spectroscopy, X-ray diffraction and scanning electron microscopy were used to identify changes produced by mechanical activation.
J.P Eymery, F Ylli
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Mechanochemical transformations and reactivity in copper sulphides

Journal of Physics and Chemistry of Solids, 2003
Mechanochemical transformations of copper sulphides were induced by processing in a Fritsch Pulverisette 6 planetary mill. The main changes during high-energy milling are the phase transformations of the djurleite Cu1.94S which is the main phase in a starting material.
P Baláž, L Takacs, E Boldižárová, E Godočı́ková   +3 more
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Cascade Mechanochemical Transformation of a Benzobarrelane Polymer

Journal of the American Chemical Society
Designing and understanding the reactivity of individual force-responsive molecules, mechanophores, has been a central topic in polymer mechanochemistry. However, we envision that when certain molecular structures are closely coupled along a polymer backbone, new mechanochemical reactivity that is absent from individual molecules may arise.
Daniel C. Lee, Erica J. Flear, Rui Xu, Ke Zheng, Todd J. Martínez, Yan Xia   +5 more
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Linear relaxation analysis of the mechanochemical transformation of collagen fibers

Biopolymers, 1972
AbstractThe isometric tensile stress generation observed when collagen fibers are immersed in aqueous solutions of lithium bromide ranging in molar concentration up to 7 was studied at 23°C. The reverse process, namely, isometric stress relaxation of the fiber occurring by subsequent immersion in distilled water, was also studied. We find that the data
I V, Yannas, D A, Olson
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Mechanochemical Transformation and Synthesis of Polymers

Rubber Chemistry and Technology, 1961
Abstract The mechanical grinding, milling, mixing, homogenization, freezing and other processes of the physico-mechanical processing of high polymers are widely used in the industries of plastics, rubbers, synthetic fibers, food products, silicates and many other branches of technology.
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Mechanochemical transformations of polythylene in the presence of Lewis acids

Polymer Science U.S.S.R., 1979
Abstract UV and IR spectroscopy, EPR and viscometry were used to establish mechanochemical transformations of high pressure polyethylene in the presence of Lewis Acids.
N.K. Baramboim, A.F. Pinyayev, L.S. Kaurova   +2 more
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