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At least 1,621 records · Page 90

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DOE OSTI2021

P-coumaroyl-CoA:monolignol transferases

The invention is directed to p-coumaroyl-CoA:monolignol transferase enzymes, nucleic acids encoding p-coumaroyl-CoA:monolignol transferase enzymes, and inhibitory nucleic acids adapted to inhibit the expression and/or translation of p-coumaroyl-CoA:monolignol transferase RNA; expression cassettes, plant cells, and plants that have or encode such nucleic acids and enzymes; and methods of making and using such nucleic acids, enzymes, expression cassettes, cells, and plants.

Ralph, John↗

DOE OSTI2021

Generation and enhancement of surface acoustic waves on a highly doped p-type III-V semiconductor substrate

A device employing the generation and enhancement of surface acoustic waves on a highly doped p-type III-V semiconductor substrate (e.g., GaAs, GaSb, InAs, or InGaAs). The device includes two SiO 2 /ZnO islands, each including a SiO 2 buffer layer deposited on the doped p-type III-V semiconductor substrate and a ZnO layer deposited on the SiO 2 buffer layer. An input interdigital transducers (IDT) and an output IDT are each patterned on one of the SiO 2 /ZnO islands. The IDTs generates surface acoustic waves along an exposed surface of the highly doped p-type III-V semiconductor substrate. The surface acoustic waves improve the photoelectric and photovoltaic properties of the device. The device is manufactured using a disclosed technique for propagating strong surface acoustic waves on weak piezoelectric materials. Also disclosed is a photodetector developed using that technique.

Dong, Boqun↗

DOE OSTI2022

P-coumaroyl-CoA:monolignol transferase

The invention relates to nucleic acids encoding a p-coumaroyl-CoA:monolignol transferase and to inhibitory nucleic acids adapted to inhibit the expression and/or translation of a p-coumaroyl-CoA:monolignol transferase RNA. Inhibition of p-coumaroyl-CoA:monolignol transferase in plants improves the incorporation of monolignol ferulates into the lignin of plants, giving rise to plant biomass that is more easily processed into useful products such as paper and biofuels.

Wilkerson, Curtis↗

DOE OSTI2023

P-coumaroyl-CoA:monolignol transferases

Ralph, John↗

DOE OSTI2021

A position and pulse shape discriminant p -terphenyl detector module

We present the development of a neutron detector array module made with para-terphenyl, a bright, fast, n/γ discriminating crystalline organic scintillator. The module is comprised of 2 cm × 2 cm × 2 cm p-terphenyl crystals that have been optically coupled together to create a pseudo-bar module. While only relying on two photo detectors, the module is capable of distinguishing interactions between up to eight crystals. Furthermore, the module retains the p-terphenyl’s pulse shape discrimination (PSD) capability. Together this makes the pseudo-bar module a promising position-sensitive neutron detector. Here we present characteristics of the pseudo-bar module - its timing resolution as well as its pulse shape and position discrimination capabilities, and briefly discuss future plans for utilizing an array of pseudo-bar modules in a useful neutron detector system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2026

Nitrogen p-type doping in polycrystalline zinc selenide telluride films

Nitrogen-doped zinc selenide telluride (N:ZnSe x Te 1−x ) is of interest because it is one of the widest-gap II–VI semiconductors that can still be doped p-type with reasonably high hole concentrations. We sputter deposit N:ZnSe x Te 1−x films, varying Se/(Se + Te), or x, from 0 to 0.7, N 2 flow rate from 0.25 to 0.75 sccm, and substrate temperature from 250 to 370 °C. Increasing x from 0 to 0.39 at the optimal temperature of 370 °C and N 2 flow rate of 0.5 sccm leads to 1.3 atomic % nitrogen incorporation and wurtzite phase stabilization. Such doping and alloying increases hole concentration from 3 × 10 18 cm −3 to 3 × 10 19 cm −3 , although mobility drops from 0.4 to 0.02 cm 2 V −1 s −1 . Our sputtered N:ZnSe 0.38 Te 0.62 has an absorption onset 0.1 eV greater than the ZnTe value of 1.87 eV. Increasing x from 0 to 0.51 enhances transmittance by moving absorption onset from 1.87 to 2.11 eV with diminished band gap bowing likely due to disorder, and increases the work function from 5.12 to 5.42 eV. This combination of tunable properties makes sputtered N:ZnSe x Te 1−x desirable for transparent p-type contacts in polycrystalline Cd(Se,Te) optoelectronic devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Cross-section measurement of the 82 Kr ($p,γ$) 83 Rb reaction in inverse kinematics

The total cross section of the 82 Kr(p,γ) 83 Rb reaction was measured for the first time at effective center-of-mass energies between 2.4 and 3.0 MeV, within the relevant Gamow window for the astrophysical γ process. The experiment took place at the National Superconducting Cyclotron Laboratory at Michigan State University using the ReA facility. A 82 Kr beam was directed onto a hydrogen gas cell located at the center of the Summing NaI(Tl) (SuN) detector. Here, the obtained spectra were analyzed using the γ-summing technique and the extracted cross section was compared to standard statistical model calculations using the non-smoker and talys codes. The comparison indicates that standard statistical model calculations tend to overproduce the cross section of the 82 Kr(p,γ) 83 Rb reaction relative to the experimentally measured values. Furthermore, the experimental data were used to provide additional constraints on the nuclear level density and the γ-ray strength function used in the statistical model calculations.

59 ≤ A ≤ 89↗

DOE OSTI2020

First Direct Measurement of Mg (α,p) 25 Al and Implications for X-Ray Burst Model-Observation Comparisons

Type-I x-ray bursts can reveal the properties of an accreting neutron star system when compared with astrophysics model calculations. However, model results are sensitive to a handful of uncertain nuclear reaction rates, such as 22 Mg(α , p). We report the first direct measurement of 22 Mg(α , p), performed with the Active Target Time Projection Chamber. The corresponding astrophysical reaction rate is orders of magnitude larger than determined from a previous indirect measurement in a broad temperature range. Overall, our new measurement suggests a less-compact neutron star in the source GS1826-24.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2023

Beam Energy Dependence of Triton Production and Yield Ratio $N_t \times N_p / N^2_d$ in Au+Au Collisions at RHIC

We report the triton (t) production in midrapidity (|y| < 0.5) Au + Au collisions at $\sqrt{s_{NN}} = 7.7-200$ GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider. The nuclear compound yield ratio ($N_t \times N_p / N^2_d$), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity ($dN_{ch}/dη$) and follows a scaling behavior. The $dN_{ch}/dη$ dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller $p_T$ acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2022

Demonstration of >6.0-kV Breakdown Voltage in Large Area Vertical GaN p-n Diodes With Step-Etched Junction Termination Extensions

Vertical gallium nitride (GaN) p-n diodes have garnered significant interest for use in power electronics where high-voltage blocking and high-power efficiency are of concern. In this article, we detail the growth and fabrication methods used to develop a large area (1 mm 2 ) vertical GaN p-n diode capable of a 6.0-kV breakdown. We also demonstrate a large area diode with a forward pulsed current of 3.5 A, an 8.3-mΩ$\cdot$cm 2 differential specific ON-resistance, and a 5.3-kV reverse breakdown. In addition, we report on a smaller area diode (0.063 mm 2 ) that is capable of 6.4-kV breakdown with a differential specific ON-resistance of 10.2 mΩ$\cdot$cm 2 , when accounting for current spreading through the drift region at a 45° angle. Finally, the demonstration of avalanche breakdown is shown for a 0.063-mm 2 diode with a room temperature breakdown of 5.6 kV. In this work, these results were achieved via epitaxial growth of a 50-μm drift region with a very low carrier concentration of <1×10 15 cm –3 and a carefully designed four-zone junction termination extension.

42 ENGINEERING↗

DOE OSTI2017

Materials Data on P(HO)4 by Materials Project

P(HO)4 crystallizes in the orthorhombic Pccn space group. The structure is three-dimensional. P4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.53 Å) and one longer (1.58 Å) P–O bond length. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.55 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.51 Å) H–O bond length. In the third H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.53 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.56 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one P4+ and one H1+ atom. In the second O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to one P4+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to one P4+ and two H1+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Materials Data on P(WO4)2 by Materials Project

P(WO4)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are two inequivalent W+5.50+ sites. In the first W+5.50+ site, W+5.50+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent WO6 octahedra and corners with three equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–12°. There are a spread of W–O bond distances ranging from 1.83–2.04 Å. In the second W+5.50+ site, W+5.50+ is bonded to six O2- atoms to form WO6 octahedra that share corners with five WO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–12°. There are a spread of W–O bond distances ranging from 1.85–2.04 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four WO6 octahedra. The corner-sharing octahedra tilt angles range from 9–23°. There are a spread of P–O bond distances ranging from 1.53–1.55 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to one W+5.50+ and one P5+ atom. In the second O2- site, O2- is bonded in a linear geometry to two W+5.50+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two W+5.50+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two W+5.50+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one W+5.50+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to one W+5.50+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent W+5.50+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one W+5.50+ and one P5+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on P(HO)3 by Materials Project

H3PO3 crystallizes in the orthorhombic Pna2_1 space group. The structure is one-dimensional and consists of four H3PO3 ribbons oriented in the (1, 0, 0) and (0, 1, 0) directions. In two of the H3PO3 ribbons, P5+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of P–O bond distances ranging from 1.62–1.67 Å. There are three inequivalent H+0.33+ sites. In the first H+0.33+ site, H+0.33+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.69 Å) H–O bond length. In the second H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one P5+ and two H+0.33+ atoms. In the third O2- site, O2- is bonded in a water-like geometry to one P5+ and one H+0.33+ atom. In two of the H3PO3 ribbons, P5+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of P–O bond distances ranging from 1.62–1.67 Å. There are three inequivalent H+0.33+ sites. In the first H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H+0.33+ site, H+0.33+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.64 Å) H–O bond length. In the third H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one P5+ and one H+0.33+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H+0.33+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one P5+ and two H+0.33+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on P(W3O10)2 by Materials Project

P(W3O10)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are six inequivalent W+5.83+ sites. In the first W+5.83+ site, W+5.83+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 2–19°. There are a spread of W–O bond distances ranging from 1.87–2.00 Å. In the second W+5.83+ site, W+5.83+ is bonded to six O2- atoms to form WO6 octahedra that share corners with five WO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–18°. There are a spread of W–O bond distances ranging from 1.85–2.05 Å. In the third W+5.83+ site, W+5.83+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 1–17°. There are a spread of W–O bond distances ranging from 1.92–1.96 Å. In the fourth W+5.83+ site, W+5.83+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three WO6 octahedra and corners with three equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–18°. There are a spread of W–O bond distances ranging from 1.85–2.06 Å. In the fifth W+5.83+ site, W+5.83+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 1–19°. There are a spread of W–O bond distances ranging from 1.91–1.98 Å. In the sixth W+5.83+ site, W+5.83+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 1–19°. There are a spread of W–O bond distances ranging from 1.89–2.02 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four WO6 octahedra. The corner-sharing octahedra tilt angles range from 10–26°. All P–O bond lengths are 1.54 Å. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one W+5.83+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two W+5.83+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two W+5.83+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one W+5.83+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one W+5.83+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the eighth O2- site, O2- is bonded in a distorted linear geometry to one W+5.83+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the eleventh O2- site, O2- is bonded in a linear geometry to two equivalent W+5.83+ atoms. In the twelfth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the thirteenth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the fourteenth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two W+5.83+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two W+5.83+ atoms. In the seventeenth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the eighteenth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the nineteenth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms. In the twentieth O2- site, O2- is bonded in a linear geometry to two W+5.83+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2022

A Molten Salt Electrochemical Process for the Preparation of Cost-Effective p-Block (Coating) Materials

Solar energy applications rely heavily on p-block elements and transition metals. Silicon is, by far, the most commonly used material in photovoltaic cells and accounts for about 85% of modules sold presently. Of late, thin film photovoltaic cells have gained momentum because of their higher efficiencies. Most of these thin film devices are made out of just five elements, namely, cadmium, tellurium, selenium, indium, gallium and copper. The present manuscript describes an elegant and inexpensive molten salt-based electrolytic process for fabricating a tellurium-coated metallic substrate. A three-electrode set up was employed to coat iridium with tellurium from a molten bath containing lithium chloride, lithium oxide and tellurium tetrachloride (LiCl-Li 2 O-TeCl 4 ) at 650 °C for a duration ranging from 30 to 120 min under a galvanostatic mode. The tellurium coating was observed to be thick, uniform, smooth and homogeneous. Additionally, the deposited tellurium did not chemically react with the iridium substrate to form intermetallic compounds, which is a good feature from the standpoint of the device’s performance characteristics. The present process, being generic in nature, shows the potential for the manufacture of both the coated substates and high-purity elements not just for tellurium but also for other p-block elements.

36 MATERIALS SCIENCE↗

NASA NTRS1986

High-speed dual-wavelength demultiplexing and detection in a monolithic superlattice p-i-n waveguide detector array

High-speed (1 Gbit/x) dual-wavelength demultiplexing and detection in a monolithic linear array of superlattice p-i-n photodetectors in a waveguide configuration is demonstrated. A crosstalk attenuation of 28 dB was achieved between two digital transmission channels with an interchannel wavelength spacing of 30 nm. The device performance is a result of an enhanced electroabsorption due to the quantum-confined Stark effect in the superlattice p-i-n diodes.

Larsson, A.↗

NASA NTRS2012

Bounding the Failure Probability Range of Polynomial Systems Subject to P-box Uncertainties

This paper proposes a reliability analysis framework for systems subject to multiple design requirements that depend polynomially on the uncertainty. Uncertainty is prescribed by probability boxes, also known as p-boxes, whose distribution functions have free or fixed functional forms. An approach based on the Bernstein expansion of polynomials and optimization is proposed. In particular, we search for the elements of a multi-dimensional p-box that minimize (i.e., the best-case) and maximize (i.e., the worst-case) the probability of inner and outer bounding sets of the failure domain. This technique yields intervals that bound the range of failure probabilities. The offset between this bounding interval and the actual failure probability range can be made arbitrarily tight with additional computational effort.

Crespo, Luis G.↗

DOE OSTI2019

Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

This work measured dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions. Our results for $ \gamma n \rightarrow K^{0} \Sigma^{0}$ are the first-ever measurements for that reaction. These data will provide insight into the properties of N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗