SEARCH · Search NASA

Results for “AgP(OF)2”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

8 records

All sources NASA NTRS DOE OSTI

DOE OSTI2020

Materials Data on Si(AgP)2 by Materials Project

Si(AgP)2 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Ag1+ is bonded in a distorted trigonal planar geometry to three equivalent P1+ atoms. There are one shorter (2.53 Å) and two longer (2.56 Å) Ag–P bond lengths. Si4- is bonded to four equivalent P1+ atoms to form corner-sharing SiP4 tetrahedra. All Si–P bond lengths are 2.26 Å. P1+ is bonded in a 2-coordinate geometry to three equivalent Ag1+ and two equivalent Si4- atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on AgP(OF)2 by Materials Project

AgP(OF)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to five O2- atoms to form AgO5 trigonal bipyramids that share corners with five PO2F2 tetrahedra, corners with three AgO5 trigonal bipyramids, and edges with three AgO5 trigonal bipyramids. There are a spread of Ag–O bond distances ranging from 2.32–2.71 Å. In the second Ag1+ site, Ag1+ is bonded to five O2- atoms to form distorted AgO5 trigonal bipyramids that share corners with five PO2F2 tetrahedra, a cornercorner with one AgO5 trigonal bipyramid, and edges with three AgO5 trigonal bipyramids. There are a spread of Ag–O bond distances ranging from 2.39–2.76 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to two O2- and two F1- atoms to form PO2F2 tetrahedra that share corners with five AgO5 trigonal bipyramids. There is one shorter (1.50 Å) and one longer (1.51 Å) P–O bond length. There is one shorter (1.56 Å) and one longer (1.57 Å) P–F bond length. In the second P5+ site, P5+ is bonded to two equivalent O2- and two equivalent F1- atoms to form PO2F2 tetrahedra that share corners with four equivalent AgO5 trigonal bipyramids. Both P–O bond lengths are 1.50 Å. Both P–F bond lengths are 1.57 Å. In the third P5+ site, P5+ is bonded to two equivalent O2- and two equivalent F1- atoms to form PO2F2 tetrahedra that share corners with six AgO5 trigonal bipyramids. Both P–O bond lengths are 1.50 Å. Both P–F bond lengths are 1.58 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Ag1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ag1+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ag1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Ag1+ and one P5+ atom. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one P5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one P5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one P5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one P5+ atom.

36 MATERIALS SCIENCE↗

NASA NTRS1995

Sinterless Fabrication Of Contact Pads On InP Devices

Research has shown that with proper choice of material, low-resistance contact pads deposited on solar cells and other devices by improved technique that does not involve sintering. Research directed at understanding mechanisms involved in contact-sintering process has resulted in identification of special group of materials that includes phosphides of gold, silver, and nickel; specifically, Au(2)P(3), AgP(2), and Ni(3)P. Incorporation of phosphide interlayer substantially reduces resistivity between gold current-carrying layer and indium phosphide substrate. Further research indicated only very thin interlayer of any of these compounds needed to obtain low contact resistance, without subjecting contact to destructive sintering process.

Weizer, Victor G.↗

DOE OSTI2020

Materials Data on AgP(XeF5)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗

DOE OSTI2024

Pectic-AGP is a major form of Arabidopsis AGPs

As a key component in cell walls of numerous organisms ranging from green algae to higher plants, AGPs play principal roles in many biological processes such as cell-cell adhesion and regulating Ca 2+ signaling pathway as a Ca 2+ -capacitor. Consistently, AGP structures vary from species to species and from tissue to tissue. To understand the functions of AGPs, it is vital to know their structural differences relative to their location in the plant. Thus, AGPs were purified from different Arabidopsis tissues. Analyses of these AGPs demonstrated that the AGPs comprised covalently linked pectin and AGP, referred to as pectic-AGPs. Importantly, these pectic-AGPs were glycosylated with a remarkable variety of polysaccharides including homogalacturonan, rhamnogalacturonan-I, and type II arabinogalactan at different ratios and lengths. Furthermore, this result not only suggests that pectic-AGP is a major form of Arabidopsis AGPs, but also supports AGPs serve as crosslinkers covalently connecting pectins with structures tailored for tissue-specific functions.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2022

Altered properties and structures of root exudate polysaccharides in a root hairless mutant of barley

Root exudates and rhizosheaths of attached soil are important features of growing roots. To elucidate factors involved in rhizosheath formation, wild-type (WT) barley (Hordeum vulgare L. cv. Pallas) and a root hairless mutant, bald root barley (brb), were investigated with a combination of physiological, biochemical, and immunochemical assays. When grown in soil, WT barley roots bound ~5-fold more soil than brb per unit root length. High molecular weight (HMW) polysaccharide exudates of brb roots had less soil-binding capacity than those of WT root exudates. Carbohydrate and glycan monoclonal antibody analyses of HMW polysaccharide exudates indicated differing glycan profiles. Relative to WT plants, root exudates of brb had reduced signals for arabinogalactan-protein (AGP), extensin, and heteroxylan epitopes. In contrast, the root exudate of 2-week-old brb plants contained ~25-fold more detectable xyloglucan epitope relative to WT. Root system immunoprints confirmed the higher levels of release of the xyloglucan epitope from brb root apices and root axes relative to WT. Epitope detection with anion-exchange chromatography indicated that the increased detection of xyloglucan in brb exudates was due to enhanced abundance of a neutral polymer. Conversely, brb root exudates contained decreased amounts of an acidic polymer, with soil-binding properties, containing the xyloglucan epitope and glycoprotein and heteroxylan epitopes relative to WT. We, therefore, propose that, in addition to physically structuring soil particles, root hairs facilitate rhizosheath formation by releasing a soil-binding polysaccharide complex.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2025

Symmetry-projected spin-AGP methods applied to spin systems

Symmetry-projected wave function methods capture static correlation by breaking and restoring the symmetries of a system. In this article, we present the symmetry-projected spin antisymmetrized geminal power (spin-AGP) state projected onto space group symmetry as well as complex conjugation, spin-flip, and time-reversal symmetries. The method is benchmarked on the 1D XXZ model and the 2D J 1 − J 2 model with square and triangular lattices. Our results indicate that symmetry projection methods provide a powerful tool for frustrated spin systems.

Antisymmetrized geminal power↗

DOE OSTI2022

Beyond carbon flux partitioning: Carbon allocation and nonstructural carbon dynamics inferred from continuous fluxes

Carbon (C) allocation and nonstructural carbon (NSC) dynamics play essential roles in plant growth and survival under stress and disturbance. However, quantitative understanding of these processes remains limited. Here, in this work, we propose a framework where we connect commonly measured carbon cycle components (eddy covariance fluxes of canopy CO 2 exchange, soil CO 2 efflux, and allometry-based biomass and net primary production) by a simple mass balance model to derive ecosystem-level NSC dynamics (NSC i ), C translocation (dC i ), and the biomass production efficiency (BPE i ) in above- and belowground plant (i = agp and bgp) compartments. We applied this framework to two long-term monitored loblolly pine (Pinus taeda) plantations of different ages in North Carolina and characterized the variations of NSC and allocation in years under normal and drought conditions. The results indicated that the young stand did not have net NSC flux at the annual scale, whereas the mature stand stored a near-constant proportion of new assimilates as NSC every year under normal conditions, which was comparable in magnitude to new structural growth. Roots consumed NSC in drought and stored a significant amount of NSC post drought. The above- and belowground dC i and BPE i varied more from year to year in the young stand and approached a relatively stable pattern in the mature stand. The belowground BPE bgp differed the most between the young and mature stands and was most responsive to drought. With the internal C dynamics quantified, this framework may also improve biomass production estimation, which reveals the variations resulting from droughts. Overall, these quantified ecosystem-scale dynamics were consistent with existing evidence from tree-based manipulative experiments and measurements and demonstrated that combining the continuous fluxes as proposed here can provide additional information about plant internal C dynamics. Given that it is based on broadly available flux data, the proposed framework is promising to improve the allocation algorithms in ecosystem C cycle models and offers new insights into observed variability in soil–plant–climate interactions.

54 ENVIRONMENTAL SCIENCES↗