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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Zr5Te4 by Materials Project

Zr5Te4 is Titanium telluride structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are two inequivalent Zr sites. In the first Zr site, Zr is bonded in a distorted square co-planar geometry to four equivalent Te atoms. All Zr–Te bond lengths are 3.11 Å. In the second Zr site, Zr is bonded to five equivalent Te atoms to form a mixture of distorted edge and corner-sharing ZrTe5 trigonal bipyramids. There are two shorter (2.94 Å) and three longer (2.95 Å) Zr–Te bond lengths. Te is bonded in a distorted hexagonal planar geometry to six Zr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BeGe3 by Materials Project

BeGe3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Be is bonded in a distorted square co-planar geometry to twelve Ge atoms. There are four shorter (2.78 Å) and eight longer (2.95 Å) Be–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded to four equivalent Be and eight Ge atoms to form a mixture of distorted face, edge, and corner-sharing GeBe4Ge8 cuboctahedra. There are four shorter (2.78 Å) and four longer (2.95 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a distorted square co-planar geometry to four equivalent Be and eight equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu2Se by Materials Project

Cu2Se crystallizes in the tetragonal P4_32_12 space group. The structure is three-dimensional. Cu1+ is bonded in a trigonal planar geometry to three equivalent Se2- atoms. There are one shorter (2.41 Å) and two longer (2.42 Å) Cu–Se bond lengths. Se2- is bonded to six equivalent Cu1+ atoms to form distorted corner-sharing SeCu6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Algebraic branch points at all loop orders from positive kinematics and wall crossing

A bstract There is a remarkable connection between the boundary structure of the positive kinematic region and branch points of integrated amplitudes in planar $$ \mathcal{N} $$ N = 4 SYM. A long-standing question has been precisely how algebraic branch points emerge from this picture. We use wall crossing and scattering diagrams to systematically study the boundary structure of the positive kinematic regions associated with MHV amplitudes. The notion of asymptotic chambers in the scattering diagram naturally explains the appearance of algebraic branch points. Furthermore, the scattering diagram construction also motivates a new coordinate system for kinematic space that rationalizes the relations between algebraic letters in the symbol alphabet. As a direct application, we conjecture a complete list of all algebraic letters that could appear in the symbol alphabet of the 8-point MHV amplitude.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Materials Data on C by Materials Project

C crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are sixteen inequivalent C sites. In the first C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.40 Å) and two longer (1.47 Å) C–C bond length. In the second C site, C is bonded in a trigonal planar geometry to three C atoms. There are a spread of C–C bond distances ranging from 1.40–1.46 Å. In the third C site, C is bonded to four C atoms to form distorted corner-sharing CC4 tetrahedra. There are a spread of C–C bond distances ranging from 1.55–1.61 Å. In the fourth C site, C is bonded to four C atoms to form distorted corner-sharing CC4 tetrahedra. There are a spread of C–C bond distances ranging from 1.53–1.64 Å. In the fifth C site, C is bonded in a trigonal planar geometry to three C atoms. In the sixth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.39 Å) and one longer (1.44 Å) C–C bond length. In the seventh C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.40 Å. In the eighth C site, C is bonded in a trigonal planar geometry to three C atoms. There are a spread of C–C bond distances ranging from 1.30–1.46 Å. In the ninth C site, C is bonded in a distorted trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the tenth C site, C is bonded in a linear geometry to two C atoms. The C–C bond length is 1.29 Å. In the eleventh C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.41 Å) and one longer (1.45 Å) C–C bond length. In the twelfth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.39 Å. In the thirteenth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.54 Å) and one longer (1.57 Å) C–C bond length. In the fourteenth C site, C is bonded to four C atoms to form distorted corner-sharing CC4 tetrahedra. The C–C bond length is 1.47 Å. In the fifteenth C site, C is bonded in a trigonal planar geometry to three C atoms. In the sixteenth C site, C is bonded in a trigonal planar geometry to three C atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Visualization of post-detonation fireball flowfields and comparison to CFD modeling

Visualization of flow structures within post-detonation fireballs has been performed for benchmark validation of numerical simulations. Custom pressed PETN explosives with a 12-mm diameter hemispherical form factor were used to produce a spherically symmetric post-detonation flow with low soot yield. Hydroxyl-radical planar laser induce fluorescence (OH-PLIF) was employed to visualize the structure ranging from approximately 10 μs to 35 μs after shock breakout from the explosive pellet. Fireball simulations were performed using the HyBurn Computational Fluid Dynamics (CFD) package. Experimental OH-PLIF results were compared to synthetic OH-PLIF from post-processing of CFD simulations. From the comparison of experimental and synthetic OH-PLIF images, CFD is shown to replicate much of the flow structure observed in the experiments, revealing potential differences in turbulent length scales and OH kinetics. Furthermore, results provide significant advancement in experimental resolution of these harsh turbulent combustion environments and validate physical models thereof.

Detonator↗
DOE OSTI2020

Materials Data on Nb2B2Mo by Materials Project

Nb2MoB2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Nb2+ is bonded in a hexagonal planar geometry to six equivalent B3- atoms. There are four shorter (2.45 Å) and two longer (2.48 Å) Nb–B bond lengths. Mo2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Mo–B bond lengths are 2.49 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Nb2+, two equivalent Mo2+, and one B3- atom. The B–B bond length is 1.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Highly fluorescent purine-containing conjugated copolymers with tailored optoelectronic properties

Conjugated copolymers containing electron donor and acceptor units in their main chain have emerged as promising materials for organic electronic devices due to their tunable optoelectronic properties. In this work, we describe the use of direct arylation polymerization to create a series of fully π-conjugated copolymers containing the highly tailorable purine scaffold as a key design element. To create efficient coupling sites, dihalopurines are flanked by alkylthiophenes to create a monomer that is readily copolymerized with a variety of conjugated comonomers, ranging from electron-donating 3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine to electron-accepting 4,7-bis(5-bromo-3-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole. The comonomer choice and electronic nature of the purine scaffold allow the photophysical properties of the purine-containing copolymers to be widely varied, with optical bandgaps ranging from 1.96–2.46 eV, and photoluminescent quantum yields as high as Φ = 0.61. Frontier orbital energy levels determined for the various copolymers using density functional theory tight binding calculations track with experimental results, and the geometric structures of the alkylthiophene-flanked purine monomer and its copolymer are found to be nearly planar. The utility of direct arylation polymerization and intrinsic tailorability of the purine scaffold highlight the potential of these fully conjugated polymers to establish structure–property relationships based on connectivity pattern and comonomer type, which may broadly inform efforts to advance purine-containing conjugated copolymers for various applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Mg2Si by Materials Project

Mg2Si is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Mg2+ is bonded in a distorted hexagonal planar geometry to six equivalent Si4- atoms. All Mg–Si bond lengths are 3.28 Å. Si4- is bonded in a 12-coordinate geometry to twelve equivalent Mg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbSeF by Materials Project

YbSeF crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Yb3+ sites. In the first Yb3+ site, Yb3+ is bonded in a distorted hexagonal planar geometry to two equivalent Se2- and six equivalent F1- atoms. Both Yb–Se bond lengths are 3.29 Å. All Yb–F bond lengths are 2.32 Å. In the second Yb3+ site, Yb3+ is bonded to six equivalent Se2- atoms to form edge-sharing YbSe6 octahedra. All Yb–Se bond lengths are 2.86 Å. Se2- is bonded in a rectangular see-saw-like geometry to four Yb3+ atoms. F1- is bonded in a trigonal planar geometry to three equivalent Yb3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co2C by Materials Project

Co2C is Hydrophilite structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Co2+ is bonded in a trigonal planar geometry to three equivalent C4- atoms. All Co–C bond lengths are 1.90 Å. C4- is bonded to six equivalent Co2+ atoms to form a mixture of corner and edge-sharing CCo6 octahedra. The corner-sharing octahedral tilt angles are 52°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CdCO3 by Materials Project

CdCO3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cd2+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All Cd–O bond lengths are 2.28 Å. C4+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All C–O bond lengths are 2.23 Å. O2- is bonded in a 4-coordinate geometry to two equivalent Cd2+, two equivalent C4+, and four equivalent O2- atoms. All O–O bond lengths are 2.23 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PtW by Materials Project

PtW crystallizes in the trigonal R-3m space group. The structure is three-dimensional. W2+ is bonded in a hexagonal planar geometry to six equivalent Pt2- atoms. All W–Pt bond lengths are 2.82 Å. Pt2- is bonded to six equivalent W2+ and six equivalent Pt2- atoms to form a mixture of corner, edge, and face-sharing PtPt6W6 cuboctahedra. All Pt–Pt bond lengths are 2.81 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TcPt by Materials Project

TcPt crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Tc2+ is bonded in a hexagonal planar geometry to six equivalent Pt2- atoms. All Tc–Pt bond lengths are 2.78 Å. Pt2- is bonded to six equivalent Tc2+ and six equivalent Pt2- atoms to form a mixture of corner, edge, and face-sharing PtTc6Pt6 cuboctahedra. All Pt–Pt bond lengths are 2.76 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Applying Configurational Complexity to the 2D Ruddlesden–Popper Crystal Structure

The layered Ruddlesden–Popper crystal structure can host a broad range of functionally important behaviors. In this work, we establish extraordinary configurational disorder in a layered Ruddlesden–Popper (RP) structure using entropy stabilization assisted synthesis. A protype A 2 CuO 4 RP cuprate oxide with five cations on the A-site sublattice is designed and fabricated into epitaxial single crystal films using pulsed laser deposition. When grown on a near lattice matched substrate, the (La 0.2 Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2 CuO 4 film features a T'-type RP structure with uniform A-site cation mixing and square-planar CuO4 units. These observations are made with a range of combined characterizations using X-ray diffraction, atomic-resolution scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray absorption spectroscopy measurements. It is further found that heteroepitaxial strain plays an important role in crystal phase formation during synthesis. Compressive strain over ~1.5% results in the formation of a non-RP cubic phase consistent with a Cu X 2O 4 spinel structure. The ability to manipulate configurational complexity and move between 2D layered RP and 3D cubic crystal structures in cuprate and related materials promises to enable flexible design strategies for a range of functionalities, such as magnetoresistance, unconventional superconductivity, ferroelectricity, catalysis, and ion transport.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeNiSnH2 by Materials Project

CeNiSnH2 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ce is bonded in a distorted hexagonal planar geometry to six equivalent H atoms. All Ce–H bond lengths are 2.57 Å. Ni is bonded in a linear geometry to three equivalent Sn and two equivalent H atoms. All Ni–Sn bond lengths are 2.52 Å. Both Ni–H bond lengths are 1.62 Å. Sn is bonded in a distorted trigonal planar geometry to three equivalent Ni atoms. H is bonded in a 1-coordinate geometry to three equivalent Ce and one Ni atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2O by Materials Project

Na2O is Hydrophilite-like structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Na1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. There are one shorter (2.31 Å) and two longer (2.33 Å) Na–O bond lengths. O2- is bonded to six equivalent Na1+ atoms to form a mixture of edge and corner-sharing ONa6 octahedra. The corner-sharing octahedral tilt angles are 53°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2O by Materials Project

K2O is Hydrophilite-like structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. K1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. There are two shorter (2.68 Å) and one longer (2.71 Å) K–O bond lengths. O2- is bonded to six equivalent K1+ atoms to form a mixture of edge and corner-sharing OK6 octahedra. The corner-sharing octahedral tilt angles are 53°.

36 MATERIALS SCIENCE↗