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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Y(BC)2 by Materials Project

YB2C2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Y is bonded in a 8-coordinate geometry to eight equivalent B and eight equivalent C atoms. All Y–B bond lengths are 2.74 Å. All Y–C bond lengths are 2.69 Å. B is bonded in a distorted trigonal planar geometry to four equivalent Y and three equivalent C atoms. There is one shorter (1.52 Å) and two longer (1.60 Å) B–C bond length. C is bonded in a 3-coordinate geometry to four equivalent Y and three equivalent B atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(BC)2 by Materials Project

ErB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Er is bonded in a 8-coordinate geometry to eight equivalent B and eight equivalent C atoms. All Er–B bond lengths are 2.72 Å. All Er–C bond lengths are 2.69 Å. B is bonded in a 2-coordinate geometry to four equivalent Er and two equivalent C atoms. Both B–C bond lengths are 1.60 Å. C is bonded in a 2-coordinate geometry to four equivalent Er, two equivalent B, and one C atom. The C–C bond length is 1.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce(BC)2 by Materials Project

CeB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Ce4+ is bonded in a 8-coordinate geometry to eight equivalent C2- atoms. All Ce–C bond lengths are 2.77 Å. B is bonded in a 2-coordinate geometry to one B and two equivalent C2- atoms. The B–B bond length is 1.66 Å. Both B–C bond lengths are 1.61 Å. C2- is bonded in a 2-coordinate geometry to four equivalent Ce4+, two equivalent B, and one C2- atom. The C–C bond length is 1.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Gd(BC)2 by Materials Project

GdB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Gd is bonded in a 8-coordinate geometry to eight equivalent B and eight equivalent C atoms. All Gd–B bond lengths are 2.78 Å. All Gd–C bond lengths are 2.75 Å. B is bonded in a 2-coordinate geometry to four equivalent Gd and two equivalent C atoms. Both B–C bond lengths are 1.61 Å. C is bonded in a 2-coordinate geometry to four equivalent Gd, two equivalent B, and one C atom. The C–C bond length is 1.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(BC)2 by Materials Project

MgB2C2 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Mg2+ is bonded in a 6-coordinate geometry to six equivalent C4- atoms. There are four shorter (2.34 Å) and two longer (2.42 Å) Mg–C bond lengths. B3+ is bonded in a trigonal planar geometry to three equivalent C4- atoms. There is one shorter (1.57 Å) and two longer (1.59 Å) B–C bond length. C4- is bonded in a distorted trigonal planar geometry to three equivalent Mg2+ and three equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tb(BC)2 by Materials Project

TbB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Tb4+ is bonded in a 8-coordinate geometry to eight equivalent C2- atoms. All Tb–C bond lengths are 2.72 Å. B is bonded in a 2-coordinate geometry to one B and two equivalent C2- atoms. The B–B bond length is 1.64 Å. Both B–C bond lengths are 1.61 Å. C2- is bonded in a 2-coordinate geometry to four equivalent Tb4+, two equivalent B, and one C2- atom. The C–C bond length is 1.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Gd(BC)2 by Materials Project

GdB2C2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Gd is bonded in a 8-coordinate geometry to eight equivalent B and eight equivalent C atoms. All Gd–B bond lengths are 2.77 Å. All Gd–C bond lengths are 2.71 Å. B is bonded in a distorted trigonal planar geometry to four equivalent Gd and three equivalent C atoms. There is one shorter (1.53 Å) and two longer (1.60 Å) B–C bond length. C is bonded in a 3-coordinate geometry to four equivalent Gd and three equivalent B atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(BC)2 by Materials Project

PrB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Pr4+ is bonded in a 8-coordinate geometry to eight equivalent C2- atoms. All Pr–C bond lengths are 2.83 Å. B is bonded in a 2-coordinate geometry to one B and two equivalent C2- atoms. The B–B bond length is 1.66 Å. Both B–C bond lengths are 1.62 Å. C2- is bonded in a 2-coordinate geometry to four equivalent Pr4+, two equivalent B, and one C2- atom. The C–C bond length is 1.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd(BC)2 by Materials Project

NdB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Nd2+ is bonded in a 8-coordinate geometry to eight equivalent C4- atoms. All Nd–C bond lengths are 2.80 Å. B3+ is bonded in an L-shaped geometry to two equivalent C4- atoms. Both B–C bond lengths are 1.62 Å. C4- is bonded in a 2-coordinate geometry to four equivalent Nd2+, two equivalent B3+, and one C4- atom. The C–C bond length is 1.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho(BC)2 by Materials Project

HoB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent B and eight equivalent C atoms. All Ho–B bond lengths are 2.73 Å. All Ho–C bond lengths are 2.70 Å. B is bonded in a 2-coordinate geometry to four equivalent Ho and two equivalent C atoms. Both B–C bond lengths are 1.60 Å. C is bonded in a 2-coordinate geometry to four equivalent Ho, two equivalent B, and one C atom. The C–C bond length is 1.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BC by Materials Project

BC1 is Boron Nitride-like structured and crystallizes in the hexagonal P-6m2 space group. The structure is two-dimensional and consists of one BC1 sheet oriented in the (0, 0, 1) direction. B3+ is bonded in a trigonal planar geometry to three equivalent C3- atoms. All B–C bond lengths are 1.55 Å. C3- is bonded in a trigonal planar geometry to three equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(BC)2 by Materials Project

SmB2C2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Sm2+ is bonded in a 8-coordinate geometry to eight equivalent C4- atoms. All Sm–C bond lengths are 2.77 Å. B3+ is bonded in an L-shaped geometry to two equivalent C4- atoms. Both B–C bond lengths are 1.61 Å. C4- is bonded in a 2-coordinate geometry to four equivalent Sm2+, two equivalent B3+, and one C4- atom. The C–C bond length is 1.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Standard Model prediction of the Bc lifetime

Applying an operator product expansion approach we update the Standard Model prediction of the B c lifetime from over 20 years ago. The non-perturbative velocity expansion is carried out up to third order in the relative velocity of the heavy quarks. The scheme dependence is studied using three different mass schemes for the b ¯ and c quarks, resulting in three different values consistent with each other and with experiment. Special focus has been laid on renormalon cancellation in the computation. Uncertainties resulting from scale dependence, neglecting the strange quark mass, non-perturbative matrix elements and parametric uncertainties are discussed in detail. The resulting uncertainties are still rather large compared to the experimental ones, and therefore do not allow for clear-cut conclusions concerning New Physics effects in the B c decay.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

New K-feldspar Pb isotope results for Mesozoic arc crust in the Pacific Northwest, U.S.A. and Canada: comparison with the Mojave-Salinia province of southern California and Implications for Baja-BC

Measurements of lead isotopic compositions in detrital K-feldspar have been increasingly used as a tool to assess sediment provenance. We compiled a database of previously published Pb isotope data from 700 bedrock K-feldspar samples and 1,423 age-corrected bedrock whole rock samples from western North American igneous and metamorphic bodies. Additionally, we report 66 new K-feldspar Pb isotope data for plutons throughout the Pacific Northwest region of the United States and British Columbia. Results show that the Pb isotope values of plutonic K-feldspar depend on the isotopically juvenile or evolved nature of underlying crust. Samples obtained from the mid Cretaceous – mid Eocene Coast Plutonic Complex, North Cascades, and Intermontane superterrane that occur west of the initial 87 Sr/ 86 Sr (Sri) = 0.706 isopleth exhibit a highly restricted 207 Pb/ 206 Pb and 208 Pb/ 206 Pb values centred upon 0.83 and 2.03, respectively. Conversely, rocks overlying older continental crust further east such as the Middle Jurassic – Late Cretaceous Omineca crystalline belt, Idaho batholith, and Boulder Batholith exhibit far greater variation of Pb isotope values that parallel the 100 Ma isochron calculated from a two-stage Pb evolution model. We demonstrate that Pb isotopic results from the Idaho and Boulder Batholith region can be used to define distinctive subregions for Pb isotopic provenance analysis, and compare these signatures to the Mojave-Salinian batholith of southern California and western Arizona, as these two areas have previously been proposed as source regions for extraregional sediment that was deposited within the Nanaimo Basin during the Campanian – Maastrichtian. Future Pb isotopic analysis of detrital K-feldspar from the Nanaimo Basin of southwestern British Columbia may effectively distinguish between potential extraregional sources separated by thousands of kilometres.

Coast Plutonic Complex↗