Mechanistic Aspects of Pyrite Oxidation in an Oxidizing Gaseous Environment:  An in Situ HATR−IR Isotope Study

2005 ◽  
Vol 39 (19) ◽  
pp. 7576-7584 ◽  
Author(s):  
Courtney R. Usher ◽  
Kristian W. Paul ◽  
Jayakumar Narayansamy ◽  
James D. Kubicki ◽  
Donald L. Sparks ◽  
...  
Keyword(s):  
Pyrite Oxidation ◽  
Gaseous Environment ◽  
Isotope Study

Os-isotope study of platinum-group minerals in chromitites in Alpine-type ultramafic intrusions and the associated placers in Borneo

1992 ◽  
Vol 56 (383) ◽  
pp. 157-164 ◽  
Author(s):  
Keiko Hattori ◽  
Klaus-Peter Burgath ◽  
Stanley R. Hart
Keyword(s):  
Igneous Rocks ◽  
Chemical Inhomogeneity ◽  
Minor Variation ◽  
Platinum Group Minerals ◽  
Isotope Study ◽  
Platinum Group ◽  
Individual Grains ◽  
A Minor ◽  
Os Isotope

Abstract187Os/186Os ratios were determined for in-situ laurite grains in Alpine-type chromitites and platinumgroup minerals (PGM) in the associated alluvial placers in Borneo, Indonesia/Malaysia. The Osisotope ratios of laurite grains in chromite defne an 187Os/186Os ratio for the 100 Ma mantle source of c. 1.04. Thelow 187Os/186Os ratios in all grains confirm the essential derivation of these platinum-group elements (PGE) from the mantle. A minor variation in 187Os/186Os ratios was detected among PGM from placers, but no variation was found within individual grains, including a grain with chemical inhomogeneity. The values are similar to those for PGM in the associated chromitites. The data are consistent with a detrital origin of PGM in placers: the placer PGM originated in the ultramafic section of ophiolities and the release of these grains from igneous rocks and their deposition in placers was almost entirely by mechanical processes.

scholarly journals Process Steps for High Quality Si-Based Epitaxial Growth at Low Temperature via RPCVD

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3733
Author(s):  
Jongwan Jung ◽  
Baegmo Son ◽  
Byungmin Kam ◽  
Yong Sang Joh ◽  
Woonyoung Jeong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Epitaxial Growth ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Ex Situ ◽  
High Quality ◽  
Reduced Pressure ◽  
Dry Cleaning ◽  
Gaseous Environment

The key process steps for growing high-quality Si-based epitaxial films via reduced pressure chemical vapor deposition (RPCVD) are investigated herein. The quality of the epitaxial films is largely affected by the following steps in the epitaxy process: ex-situ cleaning, in-situ bake, and loading conditions such as the temperature and gaseous environment. With respect to ex-situ cleaning, dry cleaning is found to be more effective than wet cleaning in 1:200 dilute hydrofluoric acid (DHF), while wet cleaning in 1:30 DHF is the least effective. However, the best results of all are obtained via a combination of wet and dry cleaning. With respect to in-situ hydrogen bake in the presence of H2 gas, the level of impurities is gradually decreased as the temperature increases from 700 °C to a maximum of 850 °C, at which no peaks of O and F are observed. Further, the addition of a hydrogen chloride (HCl) bake step after the H2 bake results in effective in-situ bake even at temperatures as low as 700 °C. In addition, the effects of temperature and environment (vacuum or gas) at the time of loading the wafers into the process chamber are compared. Better quality epitaxial films are obtained when the samples are loaded into the process chamber at low temperature in a gaseous environment. These results indicate that the epitaxial conditions must be carefully tuned and controlled in order to achieve high-quality epitaxial growth.

Progress in imaging in a gaseous environment: in situ techniques and applications using environmental SEM (ESEM)

2012 ◽  
Vol 18 (S2) ◽  
pp. 1070-1071
Author(s):  
D.J. Stokes
Keyword(s):  
In Situ Techniques ◽  
Gaseous Environment ◽  
Environmental Sem

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

scholarly journals Small Antarctic micrometeorites: A mineralogical and in situ oxygen isotope study

2005 ◽  
Vol 40 (6) ◽  
pp. 917-932 ◽  
Author(s):  
Matthieu GOUNELLE ◽  
Cécile ENGRAND ◽  
Michel MAURETTE ◽  
Gero KURAT ◽  
Kevin D. McKEEGAN ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotope Study

IN-SITU OXYGEN ISOTOPE STUDY OF TOURMALINE AND QUARTZ: INSIGHTS INTO THE PROGRADE TEMPERATURE HISTORY

2017 ◽  
Author(s):  
Barbara L. Dutrow ◽  
◽  
Katharina Marger ◽  
Benita Putlitz ◽  
Darrell J. Henry ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Temperature History ◽  
Isotope Study
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