نتایج جستجو برای: carbonaceous phosphorites

تعداد نتایج: 4406  

2015
Osamu Seki Kimitaka Kawamura James A. P. Bendle Yusuke Izawa Ikuko Suzuki Takayuki Shiraiwa Yoshiyuki Fujii

Carbonaceous aerosols influence the climate via direct and indirect effects on radiative balance. However, the factors controlling the emissions, transport and role of carbonaceous aerosols in the climate system are highly uncertain. Here we investigate organic tracers in ice cores from Greenland and Kamchatka and find that, throughout the period covered by the records (1550 to 2000 CE), the co...

2009
B. T. De Gregorio R. M. Stroud L. R. Nittler G. D. Cody

Introduction: The Stardust mission captured dust particles from comet 81P/Wild 2 and returned them to Earth. Since this material has been cryogenically stored within the comet for billions of years, the Star-dust samples represent early nebular condensates and some presolar material, identified by anomalous isotopic fractionation outside the range of solar values. Carbonaceous matter has been i...

Journal: :Science 1981
P P Smith P R Buseck

High-resolution transmission electron microscopy, shows that carbon in the Allende carbonaceous chondrite meteorite is predominantly a poorly crystalline graphite. Such material is of interest as an important carrier of the isotopically anomalous noble gases found in carbonaceous chondrites.

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2014
Craig P Marshall Alison Olcott Marshall

The search for sp(2)-bonded carbonaceous material is one of the major life detection strategies of the astrobiological exploration programmes of National Aeronautics and Space Administration and European Space Agency (ESA). The ESA ExoMars rover scheduled for launch in 2018 will include a Raman spectrometer with the goal of detecting sp(2)-bonded carbonaceous material as potential evidence of a...

Journal: :Atmospheric chemistry and physics 2012
Y Huang S Wu M K Dubey N H F French

Carbonaceous aerosols including organic carbon and black carbon have significant implications for both climate and air quality. In the current global climate or chemical transport models, a fixed hydrophobic-to-hydrophilic conversion lifetime for carbonaceous aerosol (τ) is generally assumed, which is usually around one day. We have implemented a new detailed aging scheme for carbonaceous aeros...

2001
S. Kwon Justine Russell R. Vidic E. Borguet

Optical techniques have been widely shown to be convenient, in-situ, and real time methods to investigate surface processes.[1] Compared with conventional surface probes, such as ion and electron spectroscopy, optical techniques are useful over a wide range of ambient conditions.[2-4] This study reports the adsorption and desorption of a model adsorbent representative of a volatile polar organi...

2010
Chandra Wickramasinghe Max K. Wallis Carl H. Gibson Jamie Wallis Shirwan Al-Mufti Nori Miyake

Three decades ago the first convincing evidence of microbial fossils in carbonaceous chondrites was discovered and reported by Hans Dieter Pflug and his collaborators. In addition to morphology, other data, notably laser mass spectroscopy, confirmed the identification of such structures as putative bacterial fossils. Balloon-borne cryosampling of the stratosphere enables recovery of fragile com...

2007
K. E. Yttri

This manuscript deals with the measurement of carbonaceous particulate matter in aerosols collected at 12 rural/background sites and 2 sub-urban sites across Europe, using, mainly, the EMEP measuring network. Taking into account the relative importance of carbonaceous material in continental atmospheric aerosols and the lack of extensive measurements of carbonaceous aerosol characteristics in r...

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