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BaPd crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ba is bonded in a 6-coordinate geometry to six equivalent Pd atoms. All Ba–Pd bond lengths are 3.28 Å. Pd is bonded in a distorted body-centered cubic geometry to six equivalent Ba and two equivalent Pd atoms. Both Pd–Pd bond lengths are 2.83 Å.
BaPd(SeO3)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.76–3.07 Å. Pd2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.03 Å) and two longer (2.05 Å) Pd–O bond lengths. Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.70–1.77 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ba2+ and one Se4+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+, one Pd2+, and one Se4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+, one Pd2+, and one Se4+ atom.
The structural, thermal, electrical transport, and magnetic properties of ternary compounds BaT 2 P 2 (T = Ru, Pd) are reported together with electronic structure calculations. Our results show that BaRu 2 P 2 crystallises in the layered tetragonal ThCr 2 Si 2 -type structure (space group I4/mmm) whereas BaPd 2 P 2 adopts the primitive tetragonal CeMg 2 Si 2 -type structure (space group P4/mmm). The combined experimental results and electronic structure calculations suggest metallic and diamagnetic ground states for both materials. Electrical transport measurements further indicate non-Fermi liquid behaviour at low temperatures. Notably, BaRu 2 P 2 exhibits an anomalous feature in the magnetic susceptibility at T ~ 260 K, similar to that observed in BaRu 2 As 2 . A comparison between the bare density of states obtained from electronic structure calculations and the experimentally estimated values suggests the presence of strong correlation effects in the material. Furthermore, the heat capacity of BaPd 2 P 2 , calculated using the full phonon dispersion relation, is in good agreement with the experimental data, particularly at low temperatures, highlighting the significant contribution of optical phonon branches to C P in this temperature range.
A series of polyimides derived from a newly synthesized diamine, namely, 4,4-bis(4-aminophenoxy)-2,2-dimethylbiphenyl (BAPD), were developed and characterized. Their physical and thermal properties were compared to polyimides based on'commercially available 2,2-bis(4-(4-aminophenoxy)phenyl)propane (BAPP).
The Heterodyne Instrument for Far Infrared (HIFI) on ESA's Herschel Space Observatory utilizes a variety of novel RF components in its five SIS receiver channels covering 480-1250 GHz and two HEB receiver channels covering 1410-1910 GHz. The local oscillator unit will be passively cooled while the focal plane unit is cooled by superfluid helium and cold helium vapors. HIFI employs W-band GaAs amplifiers, InP HEMT low noise IF amplifiers, fixed tuned broadband planar diode multipliers, high power W-bapd Isolators, and novel material systems in the SIS mixers. The National Aeronautics and Space Administration through the Jet Propulsion Laboratory is managing the development of the highest frequency (1119-1250 GHz) SIS mixers, the local oscillators oscillators for the three highest frequency receivers as well as W-band power amplifiers, high power W-band isolators, varactor diode devices for all high frequency multipliers and InP HEMT components for all the receiver channels intermediate frequency amplifiers. The NASA developed components represent a significant advancement in the available performance. This paper presents an update of the performance and the current state of development.