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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on K2LiAlP2 by Materials Project

K2LiAlP2 is Matlockite-derived structured and crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. K1+ is bonded to five equivalent P3- atoms to form distorted KP5 trigonal bipyramids that share corners with six equivalent LiP4 tetrahedra, corners with six equivalent AlP4 tetrahedra, corners with four equivalent KP5 trigonal bipyramids, edges with two equivalent LiP4 tetrahedra, edges with two equivalent AlP4 tetrahedra, and edges with eight equivalent KP5 trigonal bipyramids. There are a spread of K–P bond distances ranging from 3.29–3.56 Å. Li1+ is bonded to four equivalent P3- atoms to form LiP4 tetrahedra that share corners with four equivalent AlP4 tetrahedra, corners with twelve equivalent KP5 trigonal bipyramids, edges with two equivalent LiP4 tetrahedra, edges with two equivalent AlP4 tetrahedra, and edges with four equivalent KP5 trigonal bipyramids. All Li–P bond lengths are 2.65 Å. Al3+ is bonded to four equivalent P3- atoms to form AlP4 tetrahedra that share corners with four equivalent LiP4 tetrahedra, corners with twelve equivalent KP5 trigonal bipyramids, edges with two equivalent LiP4 tetrahedra, edges with two equivalent AlP4 tetrahedra, and edges with four equivalent KP5 trigonal bipyramids. All Al–P bond lengths are 2.44 Å. P3- is bonded in a 9-coordinate geometry to five equivalent K1+, two equivalent Li1+, and two equivalent Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K5BrCl4 by Materials Project

K5BrCl4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six Cl1- atoms to form a mixture of edge and corner-sharing KCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (3.22 Å) and three longer (3.23 Å) K–Cl bond lengths. In the second K1+ site, K1+ is bonded to six equivalent Cl1- atoms to form a mixture of edge and corner-sharing KCl6 octahedra. The corner-sharing octahedral tilt angles are 0°. All K–Cl bond lengths are 3.23 Å. In the third K1+ site, K1+ is bonded to three equivalent Br1- and three equivalent Cl1- atoms to form a mixture of edge and corner-sharing KBr3Cl3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. All K–Br bond lengths are 3.29 Å. All K–Cl bond lengths are 3.19 Å. Br1- is bonded to six equivalent K1+ atoms to form BrK6 octahedra that share corners with six equivalent ClK6 octahedra, edges with six equivalent BrK6 octahedra, and edges with six equivalent ClK6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded to six K1+ atoms to form ClK6 octahedra that share corners with three equivalent BrK6 octahedra, corners with three equivalent ClK6 octahedra, edges with three equivalent BrK6 octahedra, and edges with nine ClK6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second Cl1- site, Cl1- is bonded to six K1+ atoms to form a mixture of edge and corner-sharing ClK6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KMg30SiO32 by Materials Project

KMg30SiO32 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. K is bonded to six O atoms to form KO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.36 Å) and two longer (2.51 Å) K–O bond lengths. There are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.96–2.21 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.06–2.37 Å. In the third Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.12 Å) and two longer (2.16 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.11 Å) and four longer (2.18 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one KO6 octahedra, an edgeedge with one SiO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–20°. There are a spread of Mg–O bond distances ranging from 2.11–2.24 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. There are a spread of Mg–O bond distances ranging from 2.13–2.17 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one KO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. There are four shorter (2.14 Å) and two longer (2.18 Å) Mg–O bond lengths. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one SiO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–12°. There are a spread of Mg–O bond distances ranging from 2.13–2.18 Å. Si is bonded to six O atoms to form SiO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There is two shorter (1.77 Å) and four longer (1.95 Å) Si–O bond length. There are fourteen inequivalent O sites. In the first O site, O is bonded to one K and five Mg atoms to form a mixture of edge and corner-sharing OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the second O site, O is bonded to five Mg and one Si atom to form OMg5Si octahedra that share corners with six OKMg5 octahedra and edges with twelve OMg5Si octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the third O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the fourth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. Both O–Mg bond lengths are 2.14 Å. In the fifth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are two shorter (2.14 Å) and two longer (2.15 Å) O–Mg bond lengths. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. In the seventh O site, O is bonded to one K, four equivalent Mg, and one Si atom to form distorted OKMg4Si octahedra that share corners with six OKMg4Si octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OKMg4Si octahedra and edges with twelve OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OKMg4Si octahedra and edges with twelve OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are two shorter (2.11 Å) and two longer (2.17 Å) O–Mg bond lengths. In the tenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. All O–Mg bond lengths are 2.15 Å. In the twelfth O site, O is bonded to one K and five Mg atoms to form a mixture of edge and corner-sharing OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are two shorter (2.13 Å) and two longer (2.18 Å) O–Mg bond lengths. In the thirteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. The O–Mg bond length is 2.13 Å. In the fourteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of O–Mg bond distances ranging from 2.13–2.15 Å.

36 MATERIALS SCIENCE↗
NASA NTRS1980

Dependence of red edge on eddy viscosity model parameters

The dependence of the red edge location on the two fundamental free parameters in the eddy viscosity treatment was extensively studied. It is found that the convective flux is rather insensitive to any reasonable or allowed value of the two free parameters of the treatment. This must be due in part to the fact that the convective flux is determined more by the properties of the hydrogen ionization region than by differences in convective structure. The changes in the effective temperature of the red edge of the RR Lyrae gap resulting from these parameter variations is quite small (approximately 150 K). This is true both because the parameter variation causes only small changes and because large changes in the convective flux are required to produce any significant change in red edge location. The possible changes found are substantially less than the approximately 600 K required to change the predicted helium abundance mass fraction from 0.3 to 0.2.

Deupree, R. G.↗
DOE OSTI2020

Materials Data on KNaSe by Materials Project

KNaSe crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded to five equivalent Se2- atoms to form distorted KSe5 trigonal bipyramids that share corners with eight equivalent NaSe4 tetrahedra, corners with eight equivalent KSe5 trigonal bipyramids, edges with six equivalent NaSe4 tetrahedra, and edges with six equivalent KSe5 trigonal bipyramids. There are a spread of K–Se bond distances ranging from 3.34–3.48 Å. Na1+ is bonded to four equivalent Se2- atoms to form NaSe4 tetrahedra that share corners with eight equivalent NaSe4 tetrahedra, corners with eight equivalent KSe5 trigonal bipyramids, edges with two equivalent NaSe4 tetrahedra, and edges with six equivalent KSe5 trigonal bipyramids. There are a spread of Na–Se bond distances ranging from 2.96–3.01 Å. Se2- is bonded in a 9-coordinate geometry to five equivalent K1+ and four equivalent Na1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNaTe by Materials Project

KNaTe crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded to five equivalent Te2- atoms to form distorted KTe5 trigonal bipyramids that share corners with eight equivalent NaTe4 tetrahedra, corners with eight equivalent KTe5 trigonal bipyramids, edges with six equivalent NaTe4 tetrahedra, and edges with six equivalent KTe5 trigonal bipyramids. There are a spread of K–Te bond distances ranging from 3.56–3.70 Å. Na1+ is bonded to four equivalent Te2- atoms to form NaTe4 tetrahedra that share corners with eight equivalent NaTe4 tetrahedra, corners with eight equivalent KTe5 trigonal bipyramids, edges with two equivalent NaTe4 tetrahedra, and edges with six equivalent KTe5 trigonal bipyramids. There are a spread of Na–Te bond distances ranging from 3.16–3.21 Å. Te2- is bonded in a 9-coordinate geometry to five equivalent K1+ and four equivalent Na1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2PbCl5 by Materials Project

K2PbCl5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K is bonded in a 8-coordinate geometry to eight Cl atoms. There are a spread of K–Cl bond distances ranging from 3.18–3.44 Å. Pb is bonded to seven Cl atoms to form distorted edge-sharing PbCl7 pentagonal bipyramids. There are a spread of Pb–Cl bond distances ranging from 2.76–2.89 Å. There are four inequivalent Cl sites. In the first Cl site, Cl is bonded to four equivalent K and one Pb atom to form ClK4Pb trigonal bipyramids that share corners with nine ClK4Pb trigonal bipyramids, corners with eight equivalent ClK2Pb2 trigonal pyramids, edges with five ClK4Pb trigonal bipyramids, edges with two equivalent ClK2Pb2 trigonal pyramids, and a faceface with one ClK4Pb trigonal bipyramid. In the second Cl site, Cl is bonded to two equivalent K and two equivalent Pb atoms to form ClK2Pb2 trigonal pyramids that share corners with eight ClK4Pb trigonal bipyramids, corners with six equivalent ClK2Pb2 trigonal pyramids, edges with five ClK4Pb trigonal bipyramids, and an edgeedge with one ClK2Pb2 trigonal pyramid. In the third Cl site, Cl is bonded to four equivalent K and one Pb atom to form ClK4Pb trigonal bipyramids that share corners with nine ClK4Pb trigonal bipyramids, corners with four equivalent ClK2Pb2 trigonal pyramids, edges with five ClK4Pb trigonal bipyramids, edges with four equivalent ClK2Pb2 trigonal pyramids, and a faceface with one ClK4Pb trigonal bipyramid. In the fourth Cl site, Cl is bonded to four equivalent K and one Pb atom to form distorted ClK4Pb trigonal bipyramids that share corners with ten ClK4Pb trigonal bipyramids, corners with four equivalent ClK2Pb2 trigonal pyramids, edges with six ClK4Pb trigonal bipyramids, and edges with four equivalent ClK2Pb2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KCd3 by Materials Project

KCd3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. K is bonded in a distorted body-centered cubic geometry to fourteen Cd atoms. There are eight shorter (3.39 Å) and six longer (3.91 Å) K–Cd bond lengths. There are two inequivalent Cd sites. In the first Cd site, Cd is bonded to four equivalent K and four equivalent Cd atoms to form a mixture of distorted edge, face, and corner-sharing CdK4Cd4 tetrahedra. All Cd–Cd bond lengths are 3.39 Å. In the second Cd site, Cd is bonded in a 8-coordinate geometry to six equivalent K and eight equivalent Cd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KCe3 by Materials Project

KCe3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent Ce atoms to form KCe12 cuboctahedra that share corners with twelve equivalent KCe12 cuboctahedra, edges with twenty-four equivalent CeK4Ce8 cuboctahedra, faces with six equivalent KCe12 cuboctahedra, and faces with twelve equivalent CeK4Ce8 cuboctahedra. All K–Ce bond lengths are 3.61 Å. Ce is bonded to four equivalent K and eight equivalent Ce atoms to form CeK4Ce8 cuboctahedra that share corners with twelve equivalent CeK4Ce8 cuboctahedra, edges with eight equivalent KCe12 cuboctahedra, edges with sixteen equivalent CeK4Ce8 cuboctahedra, faces with four equivalent KCe12 cuboctahedra, and faces with fourteen equivalent CeK4Ce8 cuboctahedra. All Ce–Ce bond lengths are 3.61 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KAc3 by Materials Project

KAc3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent Ac atoms to form KAc12 cuboctahedra that share corners with twelve equivalent KAc12 cuboctahedra, edges with twenty-four equivalent AcK4Ac8 cuboctahedra, faces with six equivalent KAc12 cuboctahedra, and faces with twelve equivalent AcK4Ac8 cuboctahedra. All K–Ac bond lengths are 4.06 Å. Ac is bonded to four equivalent K and eight equivalent Ac atoms to form AcK4Ac8 cuboctahedra that share corners with twelve equivalent AcK4Ac8 cuboctahedra, edges with eight equivalent KAc12 cuboctahedra, edges with sixteen equivalent AcK4Ac8 cuboctahedra, faces with four equivalent KAc12 cuboctahedra, and faces with fourteen equivalent AcK4Ac8 cuboctahedra. All Ac–Ac bond lengths are 4.06 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KCa3 by Materials Project

KCa3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent Ca atoms to form KCa12 cuboctahedra that share corners with twelve equivalent KCa12 cuboctahedra, edges with twenty-four equivalent CaK4Ca8 cuboctahedra, faces with six equivalent KCa12 cuboctahedra, and faces with twelve equivalent CaK4Ca8 cuboctahedra. All K–Ca bond lengths are 4.07 Å. Ca is bonded to four equivalent K and eight equivalent Ca atoms to form CaK4Ca8 cuboctahedra that share corners with twelve equivalent CaK4Ca8 cuboctahedra, edges with eight equivalent KCa12 cuboctahedra, edges with sixteen equivalent CaK4Ca8 cuboctahedra, faces with four equivalent KCa12 cuboctahedra, and faces with fourteen equivalent CaK4Ca8 cuboctahedra. All Ca–Ca bond lengths are 4.07 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPr3 by Materials Project

KPr3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent Pr atoms to form KPr12 cuboctahedra that share corners with twelve equivalent KPr12 cuboctahedra, edges with twenty-four equivalent PrK4Pr8 cuboctahedra, faces with six equivalent KPr12 cuboctahedra, and faces with twelve equivalent PrK4Pr8 cuboctahedra. All K–Pr bond lengths are 3.83 Å. Pr is bonded to four equivalent K and eight equivalent Pr atoms to form PrK4Pr8 cuboctahedra that share corners with twelve equivalent PrK4Pr8 cuboctahedra, edges with eight equivalent KPr12 cuboctahedra, edges with sixteen equivalent PrK4Pr8 cuboctahedra, faces with four equivalent KPr12 cuboctahedra, and faces with fourteen equivalent PrK4Pr8 cuboctahedra. All Pr–Pr bond lengths are 3.83 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KLa3 by Materials Project

KLa3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent La atoms to form KLa12 cuboctahedra that share corners with twelve equivalent KLa12 cuboctahedra, edges with twenty-four equivalent LaK4La8 cuboctahedra, faces with six equivalent KLa12 cuboctahedra, and faces with twelve equivalent LaK4La8 cuboctahedra. All K–La bond lengths are 3.86 Å. La is bonded to four equivalent K and eight equivalent La atoms to form LaK4La8 cuboctahedra that share corners with twelve equivalent LaK4La8 cuboctahedra, edges with eight equivalent KLa12 cuboctahedra, edges with sixteen equivalent LaK4La8 cuboctahedra, faces with four equivalent KLa12 cuboctahedra, and faces with fourteen equivalent LaK4La8 cuboctahedra. All La–La bond lengths are 3.86 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Electron-Phonon Renormalization in the Proton-Conducting Electrolyte Ba Zr O 3 and Its Implications for High-Temperature Electrolysis

Electrical leakage is an inherent problem in solid-oxide fuel and electrolyzer cells, limiting their energy-conversion efficiency. High concentrations of electrons or holes can exacerbate this issue. However, it is largely unclear how the typical high operating temperatures of the systems influence their charge-carrier concentrations. In this work, we use first-principles calculations to examine how lattice vibrations impact electrical conductivity in conventional electrolytes, using Ba Zr O 3 as a representative material. Our analysis shows that phonon-induced shifts in the band gap and band edges lead to a dramatic increase in p -type carrier concentrations at temperatures above 600 K, compared to models that neglect temperature effects. Additionally, we reveal the importance of oxygen-ion motion on band-edge positions, which makes valence-band-edge shift dominate the band-gap change. Our study provides a protocol for calculating phonon-induced changes in similar oxides, paving the way for interrogating electrical leakage in electrolytes for high-temperature operation. Published by the American Physical Society 2025

25 ENERGY STORAGE↗
DOE OSTI2020

Materials Data on K(SnAu)3 by Materials Project

K(AuSn)3 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. K is bonded in a 10-coordinate geometry to six equivalent Au and four equivalent Sn atoms. There are two shorter (3.47 Å) and four longer (3.62 Å) K–Au bond lengths. All K–Sn bond lengths are 3.59 Å. There are two inequivalent Au sites. In the first Au site, Au is bonded in a 1-coordinate geometry to three equivalent K, three equivalent Au, and four Sn atoms. There are two shorter (2.92 Å) and one longer (3.30 Å) Au–Au bond lengths. There are a spread of Au–Sn bond distances ranging from 2.81–2.93 Å. In the second Au site, Au is bonded in a 7-coordinate geometry to seven Sn atoms. There are a spread of Au–Sn bond distances ranging from 2.91–2.98 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 4-coordinate geometry to two equivalent K and four Au atoms. In the second Sn site, Sn is bonded to seven Au atoms to form distorted edge-sharing SnAu7 hexagonal pyramids.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Simulation of brush insert for leading-edge-passage convective heat transfer

Current and proposed high speed aircraft have high leading edge heat transfer (to 160 MW/sq m, 100 Btu/sq in/sec) and surface temperatures to 1370 K (2000 F). Without cooling, these surfaces could not survive. In one proposal the coolant hydrogen is circulated to the leading edge through a passage and returned to be consumed by the propulsion system. Simulated flow studies and visualizations have shown flow separation within the passage with a stagnation locus that isolates a zone of recirculation at the most critical portion of the passage, namely the leading edge itself. A novel method is described for mitigating the flow separation and the isolated recirculation zones by using a brush insert in the flow passage near the leading edge zone, thus providing a significant increase in heat transfer.

Hendricks, R. C.↗
NASA NTRS1991

Observations of lightning processes using VHF radio interferometry

A single station, multiple baseline radio interferometer was used to locate the direction of VHF radiation from lightning discharges with microsec time resolution. Radiation source directions and electric field waveforms were analyzed for various types of breakdown events. These include initial breakdown and K type events of in-cloud activity, and the leaders of initial and subsequent strokes to ground and activity during and following return strokes. Radiation during the initial breakdown of a flash and in the early stages of initial leaders to ground is found to be similar. In both instances, the activity consists of localized bursts of radiation that are intense and slow moving. Motion within a given burst is unresolved by the interferometer. Radiation from in-cloud K type events is essentially the same as that from dart leaders; in both cases it is produced at the leading edge of a fast moving streamer that propagates along a well defined, often extensive path. K type events are sometimes terminated by fast field changes that are similar to the return stroke initiated by dart leaders; such K type events are the in-cloud analog of the dart leader return stroke process.

Rhodes, C. T.↗
DOE OSTI2020

Materials Data on KEu3 by Materials Project

KEu3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent Eu atoms to form KEu12 cuboctahedra that share corners with twelve equivalent KEu12 cuboctahedra, edges with twenty-four equivalent EuK4Eu8 cuboctahedra, faces with six equivalent KEu12 cuboctahedra, and faces with twelve equivalent EuK4Eu8 cuboctahedra. All K–Eu bond lengths are 4.16 Å. Eu is bonded to four equivalent K and eight equivalent Eu atoms to form EuK4Eu8 cuboctahedra that share corners with twelve equivalent EuK4Eu8 cuboctahedra, edges with eight equivalent KEu12 cuboctahedra, edges with sixteen equivalent EuK4Eu8 cuboctahedra, faces with four equivalent KEu12 cuboctahedra, and faces with fourteen equivalent EuK4Eu8 cuboctahedra. All Eu–Eu bond lengths are 4.16 Å.

36 MATERIALS SCIENCE↗