Results 321 to 330 of about 162,686 (360)

Mesoporous Calcite by Polymer Templating

Crystal Growth & Design, 2008
Layered calcite crystals with internal 10−50 nm pores are precipitated from aqueous solution containing a polymer−peptide conjugate that aggregates into pore-forming templates. The zwitterionic peptide sequence behaves as the “binding block” of a double-hydrophilic block copolymer, facilitating templating, nucleation inhibition, and stabilization of ...
G. Page, M., Nassif, N., G. Börner, H., Antonietti, M., Cölfen, H.   +4 more
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Influence of Mg2+ on the kinetics of calcite precipitation and calcite crystal morphology

Chemical Geology, 2000
Abstract The kinetics of calcite growth in the presence of Mg2 has been studied by both a pH free drift method and by visual observation. Our experiments show that the calcite growth rate is reduced by the presence of Mg2+. The higher the Mg/Ca ratio in the solution, the lower the growth rate in a CaCO3 supersaturated solution.
Richard A. Dawe, Yuping Zhang
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Dissociation of magnesian calcites [PDF]

Experientia, 1970
Es wurde die Dissoziationstemperatur fur verschiedene synthetische und naturliche Calcite und Mg-Calcite bestimmt. Die Dissoziationstemperatur ist abhangig vom Mg-Gehalt des Gitters.
K. V. G. K. Gokhale, T. C. Rao
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Bacterial genesis of calcite

Journal of Crystal Growth, 1994
Abstract Spherulites and polycrystalline aggregates of calcite were produced by the bacteria activity of Escherichia coli within the gel medium. Also the block-like micro-aggregates and single crystals of calcite were obtained due to association of Escherichia coli and staphylococcus aureus.
V.I. Katkova, Vladimir I. Rakin
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Thermodynamic and kinetic description of dolomitization of calcite and calcitization of dolomite (dedolomitization)

Carbonates and Evaporites, 1988
Replacement dolomitization of calcite is a chemical process where dolomite comes to occupy the spatial position and volume of calcite through simultaneous dissolution of calcite and precipitation of dolomite without effecting a volume change in the crystalline portion of the rock.
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Birefringence of Quartz and Calcite

Journal of the Optical Society of America, 1959
The measured birefringences of quartz and calcite plates are given at several visible wavelengths for temperatures of 20° and 40°C.
W. H. Steel, R. N. Smartt
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Twinning and Detwinning in Calcite

Journal of Applied Physics, 1969
Twinning and detwinning in calcite were studied by means of selective etching and sound-attenuation measurements in order to investigate dislocation behavior during these processes. Twinning was accompanied by an increase in attenuation caused by discontinuous dislocation multiplication in the twin lamella.
J. J. Gilman, H. Kaga
openaire   +2 more sources

Dissolution of aragonite, Mg-calcite, and calcite in the North Atlantic Ocean

Geology, 1975
Direct measurements indicate that rapid dissolution of aragonite and Mg-calcite in the central Sargasso Sea begins 1,000 m deeper (3,500 and 4,400 m, respectively) than observed carbonate dissolution depths for these two minerals. Thus, whereas the rate of dissolution appears to be controlled by the degree of saturation, the carbonate content of ...
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Phototransferred Thermoluminescence in Calcite

Radiation Protection Dosimetry, 1990
Abstract The effect of ultraviolet (UV) radiation on the thermoluminescent properties of Brazilian calcite was studied, using both untreated (without any treatment in the laboratory) and treated samples (with a heat treatment at 400 oC for 1 h followed by a gamma ray exposure of 7.5 C.Kg-1). The glow curve of the untreated samples showed
Emico Okuno, J.F. Lima, Elisabeth Mateus Yoshimura, Piotr Trzesniak   +3 more
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Modeling the calcite lysocline

Journal of Geophysical Research: Oceans, 1991
A numerical model of calcite dissolution in contact with sediment pore water is used to predict the depth and shape of the calcite lysocline in the deep sea. Model results are compared with lysocline data from 13 regions in the Atlantic, Pacific, and Indian Oceans.
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