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At least 1,711 records · Page 95
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Review—hexagonal boron nitride epilayers: Growth, optical properties and device applications

This paper provides a brief overview on recent advances made in authors’ laboratory in epitaxial growth and optical studies of hexagonal boron nitride (h-BN) epilayers and heterostructures. Photoluminescence spectroscopy has been employed to probe the optical properties of h-BN. It was observed that the near band edge emission of h-BN is unusually high and is more than two orders of magnitude higher than that of high quality AlN epilayers. It was shown that the unique quasi-2D nature induced by the layered structure of h-BN results in high optical absorption and emission. The impurity related and near band-edge transitions in h-BN epilayers were probed for materials synthesized under varying ammonia flow rates. Our results have identified that the most dominant impurities and deep level defects in h-BN epilayers are related to nitrogen vacancies. By growing h-BN under high ammonia flow rates, nitrogen vacancy related defects can be eliminated and epilayers exhibiting pure free exciton emission have been obtained. Deep UV and thermal neutron detectors based on h-BN epilayers were shown to possess unique features. Lastly, it is our belief that h-BN will lead to many potential applications from deep UV emitters and detectors, radiation detectors, to novel 2D photonic and electronic devices.

36 MATERIALS SCIENCE↗
DOE OSTI2021

jialiu232/MetaFunPrimer_paper_info

Genes belonging to the same functional group may include numerous and variable gene sequences, making characterizing and quantifying difficult. Therefore, high-throughput design tools are needed to simultaneously create primers for improved quantification of target genes. We developed MetaFunPrimer, a bioinformatic pipeline, to design primers for numerous genes of interest. This tool also enables gene target prioritization based on ranking the presence of genes in user-defined references, such as environment-specific metagenomes. Given inputs of protein and nucleotide sequences for gene targets of interest and an accompanying set of reference metagenomes or genomes, MetaFunPrimer generates primers for ranked genes of interest. To demonstrate the usage and benefits of MetaFunPrimer, a total of 78 primer pairs were designed to target observed ammonia monooxygenase subunit A (amoA) genes of ammonia-oxidizing bacteria (AOB) in 1,550 publicly available soil metagenomes. We demonstrate computationally that these amoA-AOB primers can cover 94% of the amoA-AOB genes observed in the 1,550 soil metagenomes compared with a 49% estimated coverage by previously published primers. Finally, we verified the utility of these primer sets in incubation experiments that used long-term nitrogen fertilized or unfertilized soils. High-throughput quantitative PCR (qPCR) results and statistical analyses showed significant differences in relative quantification patterns between the two soils, and subsequent absolute quantifications also confirmed that target genes enumerated by six selected primer pairs were significantly more abundant in the nitrogen-fertilized soils. This new tool gives microbial ecologists a new approach to assess functional gene abundance and related microbial community dynamics quickly and affordably.

Liu, Jia↗
DOE OSTI2024

H2Integrate [SWR-23-31]

H2Integrate(H2I) is an open-source Python package for hybrid systems engineering design and technoeconomic analysis. It models and optimizes hybrid energy plants that produce electricity, hydrogen, ammonia, steel, and other products. H2Integrate is designed to be flexible and extensible, allowing users to create their own components and models for various energy systems. The tool currently includes distributed energy generation (wind, solar, wave, tidal), battery storage, hydrogen, ammonia, methanol, and steel technologies. Other elements such as desalination systems, pipelines, compressors, and storage systems can also be included as developed by users. Some modeling capabilities in H2Integrate are provided by integrating existing tools, such as HOPP, PySAM, ORBIT, and ProFAST. The H2Integrate tool is built on top of NASA's OpenMDAO framework, which provides a powerful and flexible environment for modeling and optimization.

King, Jennifer [National Renewable Energy Laborato↗
DOE OSTI2026

Plant-Nitrifier Interactions in Topsoil and Subsoil

Plants can influence soil microbes through resource acquisition and interference competition, with consequences for ecosystem function such as nitrification. However, how plants alter soil conditions to influence nitrifiers and nitrification rates remains poorly understood, especially in the subsoil. Here, coupling the 15N isotopic pool dilution technique, high throughput sequencing and in situ soil O2 monitoring, we investigated how a deep-rooted perennial grass, miscanthus, versus an adjacent shallow-rooted turfgrass reference shapes nitrifier assembly and function along 1 m soil profiles. In topsoil, the suppression of ammonia (NH3) oxidizing archaea (AOA) and gross nitrification rates in miscanthus relative to the reference likely resulted from nitrifiers being outcompeted by plant roots and heterotrophic bacteria for ammonium (NH4+). The stronger tripartite competition under miscanthus may have been caused in part by the lower soil organic matter (SOM) content, which supported lower gross nitrogen (N) mineralization, the major soil process that produces NH4+. In contrast, below 10 cm soil depth, significantly greater gross nitrification rates were observed in miscanthus compared to the reference. This was likely driven by the significantly lower oxygen (O2) in miscanthus than reference subsoil, which selected against aerobic heterotrophic bacteria but in favor of AOA. Overall, we found that plants can regulate AOA community structure and function through different mechanisms in topsoil and subsoil, with suppression of nitrification in topsoil and enhancement of nitrification in subsoil.

Field Data↗
DOE OSTI2024

Comparing the Recovery of Arbuscular and Ectomycorrhizal Stands from Long-Term Nitrogen Fertilization at the Fernow Experimental Forest, WV (2021 and 2022)

This data was generated to answer the research question: After the end of a 30-year nitrogen (N) fertilization experiment in an Eastern temperate forest, to what extent do plant microbial interactions and carbon cycling in arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) dominated stands follow different recovery trajectories?The soil and the roots used in this dataset were sampled from two watersheds (N-fertilized watershed 3 and Reference watershed 7) with 6 AM and 6 ECM dominated stands each, over the course of three months (June, July, August) in 2021 and 2022. The "All_Roots.csv" data includes fine root biomass (in g) scaled to sampled soil (m2) (Scaled_Rt_Bm_gm2), and AM and ECM root colonization (%) in two soil fractions: the organic horizon (O) and the mineral horizon (B). The "All_Enzymes.csv" data includes extracellular soil enzyme activity (N-acetyl-glucosaminidase (NAG), acid phosphatase (AP), β-glucosidase (BG), phenol oxidase and peroxidase), and the ratios of BG to AP (BG:AP) and BG to NAG (BG:NAG) in three soil fractions: the organic horizon (O), the bulk soil (B), and the rhizosphere (R).The "All_Nmin" data includes inorganic N (NO3- and NH4+) pools (unit: μg of N per g of dry soil) measured pre- (I_Nitrate_ugNgsoil and I_Ammonia_ugNgsoil) and post-incubation (F_Nitrate_ugNgsoil and F_Ammonia_ugNgsoil), as well as calculated nitrification (Nitrification_day) and nitrogen mineralization (Mineralization_day) rates per day, in three soil fractions: the organic horizon (O), the bulk soil (B), and the rhizosphere (R).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Depth-resolved sagebrush root metabolomics, rhizosphere microbial communities, and geochemistry at the East River Watershed

This data set consists of results from soil nutrient profile, untargeted metabolomics, mass spec imaging, and amplicon sequencing. Data for soil nutrient profile includes common cations (Ca, Mg, Na, and K etc.) extracted from 3 digesting steps – ammonia acetate (for exchangeable cations), nitric acid (for acid dissolved fraction), and hydrofluoric acid/perchloric acid (HF/HClO4) for whole soil digestion. It also includes concentration of organic carbon, inorganic nitrogen (ammonia and nitrate) and phosphorus (Bray-1 P and nitric acid extract), and total nitrogen and phosphorus. Data for untargeted metabolomics includes metabolomic profile for root exudate/tissues and soil extracts from depths at surface soil to saprolite, that were measured using gas chromatography – mass spectrometry (GC-MS), and liquid chromatography – tandem mass spectrometry (LC-MS/MS). Data for mass spec imaging includes spatial distribution of metabolites that were detected and annotated with Fourier transformation ion cyclotron resonance mass spectrometer (FTICR-MS). Data for amplicon sequencing includes the base paired 16S and ITS ribosomal RNA sequences from Miseq Illumina sequencing. All samples were collected from 2 sampling campaign October 2022 and June 2023. Collectively, these datasets enable a mechanistic evaluation of how nutrient acquisition, especially nitrogen and phosphorus, differs between shallow roots operating in soil and deep roots functioning within the fractured bedrock zone. All files are provided as comma-separated values (CSV) fies (.csv) and (GZIP) file (.gz). The compressed .gz FASTQ files can be read directly in R using the dada2 package as part of the amplicon sequence analysis workflow. This work was supported by the Watershed Function Science Focus Area at Lawrence Berkeley National Laboratory funded by the US Department of Energy, Office of Science, Biological and Environmental Research under Contract No. DE-AC02-05CH11231. This research was performed on a project award 60563 (https://dx.doi.org/10.46936/expl.proj.2022.60563/60008727) from the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility sponsored by the Biological and Environmental Research program under Contract No. DE-AC05-76RL01830.

EARTH SCIENCE > AGRICULTURE > SOILS > CARBON↗
DOE OSTI2020

Materials Data on H5N2ClO4 by Materials Project

NH2NH3ClO4 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of eight ammonia molecules, eight ammonia molecules, and eight ClO4 clusters. In each ClO4 cluster, there are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Cl1- atom. The O–Cl bond length is 1.46 Å. In the second O2- site, O2- is bonded in a single-bond geometry to one Cl1- atom. The O–Cl bond length is 1.46 Å. In the third O2- site, O2- is bonded in a single-bond geometry to one Cl1- atom. The O–Cl bond length is 1.46 Å. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Cl1- atom. The O–Cl bond length is 1.48 Å. Cl1- is bonded in a tetrahedral geometry to four O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H3N by Materials Project

NH3 is Ammonia structured and crystallizes in the cubic P2_13 space group. The structure is zero-dimensional and consists of four ammonia molecules. N3- is bonded in a trigonal non-coplanar geometry to three equivalent H1+ atoms. All N–H bond lengths are 1.03 Å. H1+ is bonded in a single-bond geometry to one N3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiH5S(NO2)2 by Materials Project

LiN2H5SO4 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional and consists of four ammonia molecules, four ammonia molecules, and one LiSO4 framework. In the LiSO4 framework, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with four equivalent SO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.94–1.99 Å. S2- is bonded to four O2- atoms to form SO4 tetrahedra that share corners with four equivalent LiO4 tetrahedra. There are a spread of S–O bond distances ranging from 1.48–1.51 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Li1+ and one S2- atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S2- atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S2- atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+ and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlH15(NF)6 by Materials Project

AlNH3F6(NH2)3(NH3)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of twelve ammonia molecules, eight ammonia molecules, and four AlNH3F6 clusters. In each AlNH3F6 cluster, Al3+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of Al–F bond distances ranging from 1.81–1.87 Å. N2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. There is one shorter (1.04 Å) and two longer (1.05 Å) N–H bond length. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N2- and one F1- atom. The H–F bond length is 1.63 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Al3+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Al3+ atom. In the third F1- site, F1- is bonded in a distorted water-like geometry to one Al3+ and one H1+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Al3+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one Al3+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on S5N2(O2F)4 by Materials Project

N2S(SO2F)4 is Ammonia-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of eight ammonia molecules, four hydrogen sulfide molecules, and sixteen SO2F clusters. In each SO2F cluster, S+2.80+ is bonded in a trigonal non-coplanar geometry to two O2- and one F1- atom. Both S–O bond lengths are 1.42 Å. The S–F bond length is 1.59 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S+2.80+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S+2.80+ atom. F1- is bonded in a single-bond geometry to one S+2.80+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H5(NO)3 by Materials Project

N2H5NO3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ammonia molecules, four ammonia molecules, and four nitric acid molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuH12(N5O4)2 by Materials Project

CuO4N2N2(NH3)4(NO2)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two ammonia molecules; four ammonia molecules; two hydroxylamine, n-hydroxy- molecules; and one CuO4N2 cluster. In the CuO4N2 cluster, Cu2+ is bonded in a distorted linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 2.65 Å. N+0.20+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Cu2+ and one N+0.20+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N+0.20+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H12Pd(N5O4)2 by Materials Project

PdN2(NH3)4(NO2)4 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two ammonia molecules, four ammonia molecules, four nitrous acid molecules, and one palladium molecule.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H6SN2 by Materials Project

NH3NH2H2(NH2)2SHS1 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ammonia molecules, four ammonia molecules, four hydrazine;sulfane molecules, four hydrogen molecules, and four hydrogen sulfide molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H3N by Materials Project

NH3 is Ammonia-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of four ammonia molecules. N3- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. All N–H bond lengths are 1.03 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H5N2Cl by Materials Project

(NH2)2(NH3)2Cl2 crystallizes in the orthorhombic Fdd2 space group. The structure is one-dimensional and consists of sixteen ammonia molecules; sixteen ammonia molecules; and sixteen Cl2 ribbons oriented in the (1, 0, 0) direction. In each Cl2 ribbon, Cl1- is bonded in a distorted linear geometry to two equivalent Cl1- atoms. Both Cl–Cl bond lengths are 1.82 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc2Cu3H36(NF)12 by Materials Project

ScH2F6ScCu2H10(N2F3)2Cu(NH)2(NH2)4(NH)2(H2)6 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of two ammonia molecules; four ammonia molecules; one copper;azanide molecule; six hydrogen molecules; one ScH2F6 cluster; and one ScCu2H10(N2F3)2 sheet oriented in the (0, 1, 0) direction. In the ScH2F6 cluster, Sc3+ is bonded in a square co-planar geometry to four F1- atoms. There is two shorter (1.95 Å) and two longer (2.01 Å) Sc–F bond length. H1+ is bonded in a bent 150 degrees geometry to two F1- atoms. There is one shorter (1.01 Å) and one longer (1.43 Å) H–F bond length. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in an L-shaped geometry to one Sc3+ and one H1+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Sc3+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one H1+ atom. In the ScCu2H10(N2F3)2 sheet, Sc3+ is bonded in a distorted square co-planar geometry to two equivalent N3- and two equivalent F1- atoms. Both Sc–N bond lengths are 2.18 Å. Both Sc–F bond lengths are 1.93 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a square co-planar geometry to two equivalent H1+ and two equivalent F1- atoms. Both Cu–H bond lengths are 1.53 Å. Both Cu–F bond lengths are 1.80 Å. In the second Cu2+ site, Cu2+ is bonded in a distorted linear geometry to two equivalent N3- and two equivalent H1+ atoms. Both Cu–N bond lengths are 1.79 Å. Both Cu–H bond lengths are 2.12 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 1-coordinate geometry to one Cu2+ and one H1+ atom. The N–H bond length is 1.02 Å. In the second N3- site, N3- is bonded in a distorted water-like geometry to one Sc3+ and two H1+ atoms. There is one shorter (1.04 Å) and one longer (1.06 Å) N–H bond length. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to two F1- atoms. There is one shorter (0.98 Å) and one longer (1.62 Å) H–F bond length. In the second H1+ site, H1+ is bonded in a distorted bent 150 degrees geometry to one N3- and one F1- atom. The H–F bond length is 1.54 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one Cu2+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one Cu2+ and one N3- atom. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a bent 120 degrees geometry to one Cu2+ and one H1+ atom. In the second F1- site, F1- is bonded in a water-like geometry to one Sc3+ and one H1+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one H1+ atom.

36 MATERIALS SCIENCE↗