Results 71 to 80 of about 1,179,358 (368)
Isotopic fractionation of carbon, deuterium and nitrogen : a full chemical study
, 2015 Context. The increased sensitivity and high spectral resolution of millimeter telescopes allow the detection of an increasing number of isotopically substituted molecules in the interstellar medium. The 14N/ 15N ratio is difficult to measure directly for
Hickson, K. M. +2 more
core +2 more sources
NITROGEN ISOTOPE ABUNDANCE MEASUREMENTS
, 1958 The abundance of the nitrogen isotopes in several source of nitrogen has been determined. In atmospheric nitrogen the absolute ratio, N/sup 14//N/sup 15/ , is 272.0 plus or minus 0.3. Small variations were observed for various sources of compressed gas, but the isotopic composition of the nitrogen isotopes of the atmosphere was constant (to 1 part in ...
Junk, Gregor, Svec, H.
openaire +4 more sources
Metal Nanoclusters for Cancer Imaging and Treatment
Advanced Functional Materials, EarlyView.This review aims to provide a comprehensive summary and discussion of the core–shell design capabilities of metal nanoclusters (NCs) at the atomic level for cancer imaging and treatment. It offers essential insights into the design principles of metal NCs while also encouraging the exploration of other nanomaterials and their potential theranostic ...
Haiguang Zhu +5 more
wiley +1 more source
Noble Gas Planetology and the Xenon Clouds of Uranus
The Planetary Science JournalNoble gases provide tracers of cosmic provenance that are accessible to a future Uranus atmospheric probe. Argon and krypton are expected to be well mixed on Uranus with respect to H _2 and He, although condensation at the winter pole may be possible ...
Kevin Zahnle
doaj +1 more source
Advanced Functional Materials, EarlyView.Rationally‐designed advanced carbon‐based single‐atom catalysts with isolated CuN2O2 active sites anchored in N,O‐doped porous carbon facilitate water dissociation and nitrate reduction, accelerating proton supply for efficient electrosynthesis of ammonia.
Yan Li +14 more
wiley +1 more source
The Impact of Initial Composition on Massive Star Evolution and Nucleosynthesis
The Astrophysical JournalWe study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the initial composition. We use the solar abundances from Lodders, and compute two different sets of initial stellar compositions ...
Christopher West +4 more
doaj +1 more source
Chemical analysis of giant stars in the young open cluster NGC 3114 [PDF]
, 2013 Context: Open clusters are very useful targets for examining possible trends in galactocentric distance and age, especially when young and old open clusters are compared.
Drake, N. A. +2 more
core +1 more source
Advanced Functional Materials, EarlyView.By turning off hydrogen bonds by bulky ethyl cinnamate ester derivatization, softwood kraft lignin can flow under elevated temperatures, providing tough fiber in the melt for high take‐up speed. Subsequently, lignin ethyl cinnamate derivatives are readily stabilized with only dilute nitric acid leading to direct carbonized fiber with outstanding ...
Qi Hua +8 more
wiley +1 more source
12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791
, 2017 Carbon isotope ratios, along with carbon and nitrogen abundances, are derived in a sample of 11 red-giant members of one of the most metal-rich clusters in the Milky Way, NGC 6791. The selected red-giants have a mean metallicity and standard deviation of
Charbonnel, Corinne +12 more
core +1 more source
Possible in situ tests of the evolution of elemental and isotopic abundances in the solar convection zone [PDF]
, 2002 Helioseismology has shown that the chemical composition of the Sun has changed over its lifetime. The surface abundance of helium and heavy elements is believed to have decreased by up to 10% in relation to their initial values.
S. Turcotte +3 more
semanticscholar +1 more source