نتایج جستجو برای: predominantly from pyrolytic origin

تعداد نتایج: 5719357  

2006
Barry J. Katz

Pyrolysis techniques were used to characterize the organic matter contained within the penetrated section and to assess the presence of heavy hydrocarbon shows. The Rock-Eval data indicate a change in organic hydrogen enrichment within the middle Miocene sequence. It appears that the level of organic enrichment may be controlled by sedimentation rate, while the organic hydrogen enrichment, as s...

Journal: :Journal of Thermal Analysis and Calorimetry 2013

2016
J. Mortimer

Simultaneous static-mode mass spectrometric measurements of nitrogen, carbon, helium, neon, and argon, extracted from the same aliquot of sample by high-resolution stepped combustion, have been made for a suite of five lunar soils. Noble gas isotope ratios show that the majority of noble gases are derived from a solar wind source; for example, at peak release temperatures of 500–600 C, Ne/Ne = ...

2010
Patricia Balaresque Georgina R. Bowden Susan M. Adams Ho-Yee Leung Turi E. King Zoë H. Rosser Jane Goodwin Jean-Paul Moisan Christelle Richard Ann Millward Andrew G. Demaine Guido Barbujani Carlo Previderè Ian J. Wilson Chris Tyler-Smith Mark A. Jobling

The relative contributions to modern European populations of Paleolithic hunter-gatherers and Neolithic farmers from the Near East have been intensely debated. Haplogroup R1b1b2 (R-M269) is the commonest European Y-chromosomal lineage, increasing in frequency from east to west, and carried by 110 million European men. Previous studies suggested a Paleolithic origin, but here we show that the ge...

Journal: :Nanoscale 2014
Dale A C Brownson Sarah A Varey Fiazal Hussain Sarah J Haigh Craig E Banks

We report the electrochemical properties of pristine monolayer, double layer and few-layer (termed quasi-) graphene grown via CVD and transferred using PMMA onto an insulating substrate (silicon dioxide wafers). Characterisation has been performed by Raman spectroscopy, optical spectroscopy, Atomic Force Microscopy and X-ray Photoelectron Spectroscopy, revealing 'true' pristine single-layer gra...

2016
Andrew Naylor Sumedh C. Talwalkar Ian A. Trail Thomas J. Joyce

The articulating surfaces of four different sizes of unused pyrolytic carbon proximal interphalangeal prostheses (PIP) were evaluated though measuring several topographical parameters using a white light interferometer: average roughness (Sa); root mean-square roughness (Sq); skewness (Ssk); and kurtosis (Sku). The radii of the articulating surfaces were measured using a coordinate measuring ma...

Several studies have been conducted to develop more accurate and precise indices for hydrocarbons source apportionment. The present study, however, develops a new multi-metric index for hydrocarbons source apportionment. It measures Poly Aromatic Hydrocarbons (PAHs) concentration at six stations with well known petrogenic origin, calculating Phe/An, Flu/Py, Chr/BaA, BaA/Chr, An/(An+Ph), Flu/(Fl...

2003
J. L. Kaae J. L. Ely A. D. Haubold

Near-isotropic pyrolytic carbon containing a small amount of co-deposited silicon carbide has been used for years as the materials from which prosthetic heart valves are fabricated [ 1 ]. Silicon carbide was introduced into this material to increase the hardness and thereby the wear resistance of the material. Silicon carbide, however, has poor thromboresistance relative to pyrolytic carbon, so...

1998
N. Miyakawa J. F. Zasadzinski

New tunneling data are reported in underdoped Bi2Sr2CaCu2O8−δ using superconductor-insulator-superconductor break junctions. Energy gaps, ∆, of 51±2, 54±2 and 57±3 meV are observed for three crystals with Tc=77, 74, and 70 K respectively. These energy gaps are nearly three times larger than for overdoped crystals with similar Tc. Detailed examination of tunneling spectra over a wide doping rang...

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