نتایج جستجو برای: silicate hydrolysis

تعداد نتایج: 48714  

2007
M. P. Li G. Zhao Aigen Li

An accurate knowledge of the mineralogy (chemical composition and crystal structure) of the silicate dust in the interstellar medium (ISM) is crucial for understanding its origin in evolved stars, the physical and chemical processing in the ISM, and its subsequent incorporation into protostellar nebulae, protoplanetary disks and cometary nuclei where it is subjected to further processing. While...

2001
David E. Harker Steven J. Desch

Silicate dust grains in the interstellar medium are known to be mostly amorphous, yet crystalline silicate grains have been observed in many long-period comets and in protoplanetary disks. Annealing of amorphous silicate grains into crystalline grains requires temperatures > ∼ 1000K, but exposure of dust grains in comets to such high temperatures is incompatible with the generally low temperatu...

2015
Jonas Bremer

To get en enhanced understanding of water in the planet forming region of protoplanetary disks, it is important to understand how dust, which is the main source of opacity affects the mid-IR emission of water. Therefore, this thesis presents a comprehensive study of the connection between the mid-IR water emission and the peak strength of the 10 μm silicate feature. Besides the investigation of...

2015
Robert J Friederichs Helen F Chappell David V Shepherd Serena M Best

Experimental chemistry and atomic modelling studies were performed here to investigate a novel ionic co-substitution in hydroxyapatite (HA). Zinc, silicate co-substituted HA (ZnSiHA) remained phase pure after heating to 1100 °C with Zn and Si amounts of 0.6 wt% and 1.2 wt%, respectively. Unique lattice expansions in ZnSiHA, silicate Fourier transform infrared peaks and changes to the hydroxyl I...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2010
Frederic Moynier Qing-Zhu Yin Keita Irisawa Maud Boyet Benjamin Jacobsen Minik T Rosing

Recent high precision (142)Nd isotope measurements showed that global silicate differentiation may have occurred as early as 30-75 Myr after the Solar System formation [Bennett V, et al. (2007) Science 318:1907-1910]. This time scale is almost contemporaneous with Earth's core formation at approximately 30 Myr [Yin Q, et al. (2002) Nature 418:949-952]. The (182)Hf-(182)W system provides a power...

2016
Yifeng Wang Carlos F. Jove-Colon Kristopher L. Kuhlman

Aqueous dissolution of silicate glasses and minerals plays a critical role in global biogeochemical cycles and climate evolution. The reactivity of these materials is also important to numerous engineering applications including nuclear waste disposal. The dissolution process has long been considered to be controlled by a leached surface layer in which cations in the silicate framework are grad...

2009
Jon K. Hillier S. Sestak

The Open University's repository of research publications and other research outputs The production of platinum-coated silicate nanoparticle aggregates for use in hypervelocity impact experiments Journal Article (2009). The production of platinum-coated silicate nanoparticle aggregates for use in hypervelocity impact experiments. Copyright and Moral Rights for the articles on this site are reta...

2013
Leliang Li Jun Zheng Yuhua Zuo Buwen Cheng Qiming Wang

Eu2O3/Si multilayer nanostructured films are deposited on Si substrates by magnetron sputtering. Transmission electron microscopy and X-ray diffraction measurements demonstrate that multicrystalline Eu silicate is homogeneously distributed in the film after high-temperature treatment in N2. The Eu2+ silicate is formed by the reaction of Eu2O3 and Si layers, showing an intense and broad room-tem...

2006
X. Kong S. S. Chakravarthula Y. Qiao

The microvoiding in crack-tip plastic zone in a partly exfoliated polyamide 6–silicate nanocomposite is investigated through the experimental measurement of microvoid size distribution and the computer simulation in context of nonlinear fracture mechanics. In order to analyze the effect of silicate content on fracture resistance, the evolution of the collective microvoids induced by the silicat...

2001
E. A. Cottrell D. Walker

Introduction: Pt nuggets found in the silicate glass of solubility experiments at low fO2 may be the quench products of Pt in solution in silicate liquid, not mechanical contaminants. Pt solubilities measured in the range of geologically interesting fO2 would then be several orders of magnitude higher than conventionally assumed. Such a finding may remove the perception of "excess" Pt in Earth'...

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