SEARCH · Engineering Papers
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
MoN crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of two MoN sheets oriented in the (0, 0, 1) direction. Mo3+ is bonded in a distorted square co-planar geometry to four equivalent N3- atoms. There are a spread of Mo–N bond distances ranging from 2.07–2.12 Å. N3- is bonded in a distorted square co-planar geometry to four equivalent Mo3+ atoms.
Ni(Pt3O4)4 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are five inequivalent Pt+2.50+ sites. In the first Pt+2.50+ site, Pt+2.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.03 Å. In the second Pt+2.50+ site, Pt+2.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.02 Å. In the third Pt+2.50+ site, Pt+2.50+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.00 Å) and two longer (2.04 Å) Pt–O bond lengths. In the fourth Pt+2.50+ site, Pt+2.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.03 Å. In the fifth Pt+2.50+ site, Pt+2.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.00 Å. Ni2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ni–O bond lengths are 2.27 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three Pt+2.50+ and one Ni2+ atom to form a mixture of corner and edge-sharing ONiPt3 trigonal pyramids. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Pt+2.50+ atoms.
SbTe crystallizes in the orthorhombic Cmmm space group. The structure is two-dimensional and consists of two SbTe sheets oriented in the (0, 1, 0) direction. Sb is bonded in a distorted square co-planar geometry to four equivalent Te atoms. All Sb–Te bond lengths are 3.15 Å. Te is bonded in a distorted square co-planar geometry to four equivalent Sb atoms.
CaSn2S5 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ca2+ is bonded in a hexagonal planar geometry to six equivalent S2- atoms. All Ca–S bond lengths are 3.25 Å. Sn4+ is bonded to four S2- atoms to form corner-sharing SnS4 tetrahedra. There are one shorter (2.34 Å) and three longer (2.43 Å) Sn–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Ca2+ and one Sn4+ atom to form a mixture of distorted corner and edge-sharing SCa3Sn tetrahedra. In the second S2- site, S2- is bonded in a water-like geometry to two equivalent Sn4+ atoms.
Pb2Sb2O7 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Pb2+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All Pb–O bond lengths are 2.50 Å. Sb5+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are six shorter (2.17 Å) and two longer (2.33 Å) Sb–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Pb2+ and two equivalent Sb5+ atoms to form a mixture of distorted corner and edge-sharing OSb2Pb2 tetrahedra. In the second O2- site, O2- is bonded to four equivalent Sb5+ atoms to form a mixture of corner and edge-sharing OSb4 tetrahedra.
Schottky barrier diodes for terahertz applications are typically fabricated as a micron to sub-micron circular anode metallization on GaAs which is contacted with a sharp wire (whisker). This structure has the benefits of the simplicity of the fabrication of the diode chip, the minimal shunt capacitance of the whisker contact and the ability of the whisker wire to couple energy to the diode. However, whisker-contacted diodes are costly to assembly and difficult to qualify for space applications. Also, complex receiver systems which require many diodes are difficult to assemble. The objective of this paper is to discuss the advantages of planar Schottky diodes for high frequency receiver applications and to summarize the problems of advancing the planar technology to the terahertz frequency range. Section 2 will discuss the structure, fabrication and performance of state-of-the-art planar Schottky diodes. In Section 3 the problems of designing and fabricating planar diodes for terahertz frequency operation are discussed along with a number of viable solutions. Section 4 summarizes the need for further research and cooperation between diode designers and RF engineers.
KO2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K is bonded in a distorted hexagonal planar geometry to six equivalent O atoms. There are a spread of K–O bond distances ranging from 2.69–2.79 Å. O is bonded in a 4-coordinate geometry to three equivalent K and one O atom. The O–O bond length is 1.36 Å.
A triangular space station deployable in orbit is described. The framework is comprized of three trusses, formed of a pair of generally planar faces consistine of foldable struts. The struts expand and lock into rigid structural engagement forming a repetition of equilater triangles and nonfolding diagonal struts interconnecting the two faces. The struts are joined together by node fittings. The framework can be packaged into a size and configuration transportable by a space shuttle. When deployed, the framework provides a large work/construction area and ample planar surface area for solar panels and thermal radiators. A plurity of modules are secured to the framework and then joined by tunnels to make an interconnected modular display. Thruster units for the space station orientation and altitude maintenance are provided.
NdCo12B6 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Nd3+ is bonded in a hexagonal planar geometry to six equivalent B3- atoms. All Nd–B bond lengths are 3.05 Å. There are two inequivalent Co+1.25+ sites. In the first Co+1.25+ site, Co+1.25+ is bonded to four equivalent B3- atoms to form a mixture of distorted edge and corner-sharing CoB4 trigonal pyramids. All Co–B bond lengths are 2.04 Å. In the second Co+1.25+ site, Co+1.25+ is bonded in a T-shaped geometry to three equivalent B3- atoms. All Co–B bond lengths are 2.10 Å. B3- is bonded in a 7-coordinate geometry to one Nd3+ and seven Co+1.25+ atoms.
PrCo12B6 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pr3+ is bonded in a hexagonal planar geometry to six equivalent B3- atoms. All Pr–B bond lengths are 3.06 Å. There are two inequivalent Co+1.25+ sites. In the first Co+1.25+ site, Co+1.25+ is bonded in a T-shaped geometry to three equivalent B3- atoms. All Co–B bond lengths are 2.10 Å. In the second Co+1.25+ site, Co+1.25+ is bonded to four equivalent B3- atoms to form a mixture of distorted edge and corner-sharing CoB4 trigonal pyramids. All Co–B bond lengths are 2.04 Å. B3- is bonded in a 7-coordinate geometry to one Pr3+ and seven Co+1.25+ atoms.
Li7Nb8O24 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are seven inequivalent Li sites. In the first Li site, Li is bonded in a trigonal planar geometry to three O atoms. There are one shorter (2.00 Å) and two longer (2.01 Å) Li–O bond lengths. In the second Li site, Li is bonded in a trigonal planar geometry to three O atoms. There are a spread of Li–O bond distances ranging from 1.99–2.03 Å. In the third Li site, Li is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.99 Å) and two longer (2.00 Å) Li–O bond length. In the fourth Li site, Li is bonded in a trigonal planar geometry to three O atoms. All Li–O bond lengths are 2.00 Å. In the fifth Li site, Li is bonded in a trigonal planar geometry to three O atoms. There are a spread of Li–O bond distances ranging from 1.98–2.01 Å. In the sixth Li site, Li is bonded in a trigonal planar geometry to three O atoms. There are a spread of Li–O bond distances ranging from 1.99–2.02 Å. In the seventh Li site, Li is bonded in a trigonal planar geometry to three O atoms. There are a spread of Li–O bond distances ranging from 2.01–2.03 Å. There are eight inequivalent Nb sites. In the first Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 29–39°. There are a spread of Nb–O bond distances ranging from 1.94–2.06 Å. In the second Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–38°. There are a spread of Nb–O bond distances ranging from 1.97–2.05 Å. In the third Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 27–39°. There are a spread of Nb–O bond distances ranging from 1.95–2.08 Å. In the fourth Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 27–40°. There are a spread of Nb–O bond distances ranging from 1.98–2.05 Å. In the fifth Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 29–38°. There are a spread of Nb–O bond distances ranging from 1.96–2.08 Å. In the sixth Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 34–39°. There are a spread of Nb–O bond distances ranging from 1.96–2.05 Å. In the seventh Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 27–40°. There are a spread of Nb–O bond distances ranging from 1.97–2.05 Å. In the eighth Nb site, Nb is bonded to six O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 27–38°. There are a spread of Nb–O bond distances ranging from 1.98–2.05 Å. There are twenty-four inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the second O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the third O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Nb atoms. In the fifth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the sixth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the seventh O site, O is bonded in a distorted trigonal non-coplanar geometry to one Li and two Nb atoms. In the eighth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the ninth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Li and two Nb atoms. In the tenth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the eleventh O site, O is bonded in a bent 150 degrees geometry to two Nb atoms. In the twelfth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the thirteenth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the fourteenth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the fifteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Li and two Nb atoms. In the sixteenth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the seventeenth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the eighteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Li and two Nb atoms. In the nineteenth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the twentieth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the twenty-first O site, O is bonded in a bent 150 degrees geometry to two Nb atoms. In the twenty-second O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms. In the twenty-third O site, O is bonded in a distorted trigonal non-coplanar geometry to one Li and two Nb atoms. In the twenty-fourth O site, O is bonded in a distorted trigonal planar geometry to one Li and two Nb atoms.
NbPt4 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Nb4+ is bonded in a hexagonal planar geometry to six equivalent Pt1- atoms. All Nb–Pt bond lengths are 2.80 Å. There are two inequivalent Pt1- sites. In the first Pt1- site, Pt1- is bonded to three equivalent Nb4+ and three equivalent Pt1- atoms to form a mixture of distorted edge and corner-sharing PtNb3Pt3 cuboctahedra. All Pt–Pt bond lengths are 2.88 Å. In the second Pt1- site, Pt1- is bonded to twelve Pt1- atoms to form PtPt12 cuboctahedra that share corners with fifteen PtNb3Pt3 cuboctahedra, edges with twenty-one PtNb3Pt3 cuboctahedra, and faces with twelve equivalent PtPt12 cuboctahedra. There are six shorter (2.83 Å) and three longer (2.84 Å) Pt–Pt bond lengths.
Mn(WB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. W2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.34 Å) and four longer (2.35 Å) W–B bond lengths. Mn2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Mn–B bond lengths are 2.34 Å. B3- is bonded in a 9-coordinate geometry to six equivalent W2+, two equivalent Mn2+, and one B3- atom. The B–B bond length is 1.87 Å.
Fe(WB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. W2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.32 Å) and four longer (2.35 Å) W–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.28 Å. B3- is bonded in a 9-coordinate geometry to six equivalent W2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.86 Å.
Nb2FeB2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Nb2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.39 Å) and four longer (2.43 Å) Nb–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.31 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Nb2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.87 Å.
Nb2CrB2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Nb2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.40 Å) and four longer (2.42 Å) Nb–B bond lengths. Cr2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Cr–B bond lengths are 2.41 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Nb2+, two equivalent Cr2+, and one B3- atom. The B–B bond length is 1.86 Å.
Mo2FeB2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Mo2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.33 Å) and four longer (2.34 Å) Mo–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.33 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Mo2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.85 Å.
Mn(MoB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Mo2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.32 Å) and four longer (2.33 Å) Mo–B bond lengths. Mn2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Mn–B bond lengths are 2.33 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Mo2+, two equivalent Mn2+, and one B3- atom. The B–B bond length is 1.87 Å.