Shedding New Light on Weak Emission-Line Quasars in the CIV-Hβ Parameter Space (open access)

Shedding New Light on Weak Emission-Line Quasars in the CIV-Hβ Parameter Space

Article describes how weak emission-line quasars (WLQs) are a subset of Type 1 quasars that exhibit extremely weak Lyα+N V λ1240 and/or C IV λ1549 emission lines. The authors investigate the relationship between emission-line properties and accretion rate for a sample of 230 `ordinary' Type 1 quasars and 18 WLQs at z<0.5 and 1.5<z<3.5 that have rest-frame ultraviolet and optical spectral measurements.
Date: April 10, 2023
Creator: Ha, Trung; Dix, Cooper; Matthews, Brandon M.; Shemmer, Ohad; Brotherton, Michael S.; Myers, Adam D. et al.
Object Type: Article
System: The UNT Digital Library
Polymeric Coatings for Skutterudite-Based Thermoelectric Materials (open access)

Polymeric Coatings for Skutterudite-Based Thermoelectric Materials

Article is a study with the main objective of mitigation of thermal degradation of skutterudite-based thermoelectric materials—so as to extend the service life of those materials and make them more attractive for industry from the economical perspective. Significant mitigation of oxidation and sublimation of thermoelectric (TE) materials was achieved.
Date: February 17, 2022
Creator: Brostow, Witold, 1934-; Chen, Ikang & Hagg Lobland, Haley E.
Object Type: Article
System: The UNT Digital Library
Momentum-Space Spin Antivortex and Spin Transport in Monolayer Pb (open access)

Momentum-Space Spin Antivortex and Spin Transport in Monolayer Pb

This article finds a nontrivial spin texture, spin antivortex, can appear at certain momenta on the Γ− K line in a 2D monolayer Pb on top of SiC.
Date: April 21, 2022
Creator: Yang, Kaijie; Wang, Yuanxi & Liu, Chao-Xing
Object Type: Article
System: The UNT Digital Library
Connecting Low- and High-redshift Weak Emission-line Quasars via Hubble Space Telescope Spectroscopy of Lyα Emission (open access)

Connecting Low- and High-redshift Weak Emission-line Quasars via Hubble Space Telescope Spectroscopy of Lyα Emission

Article presents ultraviolet spectroscopy covering the Lyα + N v complex of six candidate low-redshift (0.9 < z < 1.5) weak emission-line quasars (WLQs) based on observations with the Hubble Space Telescope.
Date: April 14, 2022
Creator: Paul, Jeremiah D.; Plotkin, Richard M.; Shemmer, Ohad; Anderson, Scott F.; Brandt, W. N.; Fan, Xiaohui et al.
Object Type: Article
System: The UNT Digital Library
Polarization in electrostatics and circuits: Computing and visualizing surface charge distributions (open access)

Polarization in electrostatics and circuits: Computing and visualizing surface charge distributions

Article describing an algorithm or computing the detailed surface charge distributions in equilibrium electrostatic situations and in steady-state DC circuits, and discuss the results of the computations of surface charge distributions for several systems.
Date: December 14, 2018
Creator: Chabay, Ruth & Sherwood, Bruce
Object Type: Article
System: The UNT Digital Library
Dual-Band High Efficiency Terahertz Meta-Devices Based on Reflective Geometric Metasurfaces (open access)

Dual-Band High Efficiency Terahertz Meta-Devices Based on Reflective Geometric Metasurfaces

Article proposing a novel reflective building block (unit cell) to work at two arbitrary terahertz frequency bands with independent phase control at each band.
Date: April 18, 2019
Creator: Lin, Yuankun; Wang, Tailei; Xie, Rensheng; Zhu, Shouzheng; Gao, Jianjun; Xin, Mingbo et al.
Object Type: Article
System: The UNT Digital Library
Topology of Black Holes’ Horizons (open access)

Topology of Black Holes’ Horizons

Article exploring the topology of black holes.
Date: April 3, 2019
Creator: Tozzi, Arturo & Peters, James F.
Object Type: Article
System: The UNT Digital Library
Prescriptions for Correcting Ultraviolet-based Redshifts for Luminous Quasars at High Redshift (open access)

Prescriptions for Correcting Ultraviolet-based Redshifts for Luminous Quasars at High Redshift

This article presents near-infrared spectroscopy of 18 luminous quasars at 2.15 < z < 3.70 that allows the authors to obtain reliable systemic redshifts for these sources.
Date: April 8, 2020
Creator: Dix, Cooper; Shemmer, Ohad; Brotherton, Michael S.; Green, Richard F.; Mason, Michelle & Myers, Adam D.
Object Type: Article
System: The UNT Digital Library
Broadband Absorption in Patterned Metal/Weakly-Absorbing-Spacer/Metal with Graded Photonic Super-Crystal (open access)

Broadband Absorption in Patterned Metal/Weakly-Absorbing-Spacer/Metal with Graded Photonic Super-Crystal

Article studying high light absorption in two devices: a stack of Au-pattern/insulator/Au-film and a stack of Au-pattern/weakly-absorbing-material/Au-film where the Au-pattern was structured in graded photonic super-crystal. Multiple-band absorption, including one near 1500 nm, in a stack of Au-pattern/spacer/Au-film was observed.
Date: April 8, 2021
Creator: Kamau, Steve; Hassan, Safaa; Alnasser, Khadijah; Zhang, Hualiang; Cui, Jingbiao & Lin, Yuankun
Object Type: Article
System: The UNT Digital Library
Topologically driven linear magnetoresistance in helimagnetic FeP (open access)

Topologically driven linear magnetoresistance in helimagnetic FeP

Article presenting a series of high magnetic field experiments on high-quality single crystals of FeP. The study shows that resistance not only increases without saturation by up to several hundred times its zero-field value by 35 T, but that it also exhibits an anomalously linear field dependence over the entire range when the field is aligned precisely along the crystallographic c-axis.
Date: April 14, 2021
Creator: Campbell, D.J.; Collini, J.; Sławińska, Jagoda; Autieri, C.; Wang, L.; Wang, K. et al.
Object Type: Article
System: The UNT Digital Library
Discovery of higher-order topological insulators using the spin Hall conductivity as a topology signature (open access)

Discovery of higher-order topological insulators using the spin Hall conductivity as a topology signature

This article shows a connection between spin Hall effect and HOTIs using a combination of ab initio calculations and tight-binding modeling. The model demonstrates how a non-zero bulk midgap spin Hall conductivity (SHC) emerges within the HOTI phase. This work guides novel experimental and theoretical advances towards higher-order topological insulator realization and applications.
Date: April 12, 2021
Creator: Costa, Marcio; Mera Acosta, Carlos; Padilha, Antonio C.M.; Cerasoli, Frank T.; Buongiorno Nardelli, Marco & Fazzio, Adalberto
Object Type: Article
System: The UNT Digital Library
Resonance modes in moiré photonic patterns for twistoptics (open access)

Resonance modes in moiré photonic patterns for twistoptics

Article studying twistoptics for manipulating optical properties in twisted moiré photonic patterns without physical rotations. The presented approach can lead toward the study of twistoptics for the manipulating of optical properties in moiré patterns with different twist angles.
Date: April 12, 2021
Creator: Alnasser, Khadijah; Kamau, Steve; Cui, Jingbiao & Lin, Yuankun
Object Type: Article
System: The UNT Digital Library
Simulation Of An Antihydrogen Gravity Experiment Utilizing Multiple Apertures (open access)

Simulation Of An Antihydrogen Gravity Experiment Utilizing Multiple Apertures

The article presents an analytical model and a Monte Carlo simulation of an antihydrogen gravity experiment that would employ multiple apertures. The model was developed with the primary goal of reducing the experimental run time necessary to determine the direction of free fall acceleration for antimatter in the gravitational field of the Earth. The experiment would confine cryogenic antihydrogen plasma for producing antihydrogen (e.g., by three-body recombination).
Date: April 19, 2013
Creator: Hedlof, R. M. & Ordonez, Carlos A.
Object Type: Article
System: The UNT Digital Library
Electrostatic storage ring with focusing provided by the space charge of an electron plasma (open access)

Electrostatic storage ring with focusing provided by the space charge of an electron plasma

Article describes an electronic storage ring that employs the space charge of an electron plasma for focusing. An advantage of the present concept is that slow ions, or even a stationary ion plasma, can be confined. The concept employs an artificially structured boundary, which is defined at present as one that produces a spatially periodic static field such that the spatial period and range of the field are much smaller than the dimensions of a plasma or charged-particle beam that is confined by the field.
Date: April 19, 2013
Creator: Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
Object Type: Article
System: The UNT Digital Library
Accelerator-based fusion with a low temperature target (open access)

Accelerator-based fusion with a low temperature target

This article reports a study of a cold target with a high Fermi energy in light of recent research that points to a new phase of hydrogen, which is hypothesized to be related to metallic hydrogen. It has been shown that if the energy transfer between injected ions and target electrons is sufficiently small, net energy gain can be achieved. As such, the target is considered to be composed of nuclei and delocalized electrons.
Date: April 19, 2013
Creator: Phillips, R. E. & Ordonez, Carlos A.
Object Type: Article
System: The UNT Digital Library
Classical trajectory Monte Carlo code for simulating ion beam focusing or defocusing with magnetic elements modeled as current loops or current lines (open access)

Classical trajectory Monte Carlo code for simulating ion beam focusing or defocusing with magnetic elements modeled as current loops or current lines

Article describes a computational tool that can be used for designing magnetic focusing or defocusing systems. A fully three-dimensional classical trajectory Monte Carlo simulation has been developed.
Date: April 19, 2013
Creator: Lane, Ryan A. & Ordonez, Carlos A.
Object Type: Article
System: The UNT Digital Library
Dual levitated coils for antihydrogen production (open access)

Dual levitated coils for antihydrogen production

Article on theoretical and experimental efforts to use dual levitated coils to confine relatively large, cold, dense non-drifting recombining antihydrogen plasmas. The theoretical effort includes the development of a classical trajectory Monte Carlo simulation of confinement. The experimental effort includes levitation of a NdFeB permanent ring magnet, which produces a magnetic field that is qualitatively similar to the field that would be produced by the two coaxial superconducting magnetic coils.
Date: April 19, 2013
Creator: Wofford, Joshua D. & Ordonez, Carlos A.
Object Type: Article
System: The UNT Digital Library
Low-temperature UV photoluminescence of ion beam synthesized Si nanoclusters embedded in Si (open access)

Low-temperature UV photoluminescence of ion beam synthesized Si nanoclusters embedded in Si

This article explores Ultraviolet (UV) photoluminescence (PL) data taken on a double Au implanted Si matrix and studied over a wide temperature range of 28-220K. The results of this study at lower temperatures indicate the emission to be coming from Si nanoclusters (NCs) embedded in the matrix.
Date: April 3, 2012
Creator: Sahu, G.; Lenka, H.P.; Mahapatra, Durga P.; Rout, B. & Das, M.P.
Object Type: Article
System: The UNT Digital Library
Spatially Periodic Electromagnetic Force Field For Plasma Confinement and Control (open access)

Spatially Periodic Electromagnetic Force Field For Plasma Confinement and Control

In this article, a theoretical understanding is developed of the single-particle reflection properties of a force field, considering the incident charged particles to have a non-drifting, isotropic velocity distribution. Classical trajectory Monte Carlo simulations and analytical modeling are employed. The initiation of an experimental effort to study force fields is described.
Date: April 17, 2012
Creator: Ordonez, Carlos A.; Pacheco, J. L. & Weathers, Duncan L.
Object Type: Article
System: The UNT Digital Library
Topological View of Flows Inside the BOLD Spontaneous Activity of the Human Brain (open access)

Topological View of Flows Inside the BOLD Spontaneous Activity of the Human Brain

Article describes study which found that persistent, recurring blood oxygen level dependent (BOLD) signals in triangulated rs-fMRI videoframes display previously undetected topological findings, i.e., vortex structures that cover brain activated regions.
Date: April 22, 2020
Creator: Don, Arjuna P. H.; Peters, James F.; Ramanna, Sheela & Tozzi, Arturo
Object Type: Article
System: The UNT Digital Library
Entropy Balance in the Expanding Universe: A Novel Perspective (open access)

Entropy Balance in the Expanding Universe: A Novel Perspective

The article describes cosmic expansion as correlated with the standpoints of local observers’ co-moving horizons. In keeping with relational quantum mechanics, which claims that quantum systems are only meaningful in the context of measurements, the authors suggest that information gets ergodically “diluted” in our isotropic and homogeneous expanding Universe, so that an observer detects just a limited amount of the total cosmic bits.
Date: April 17, 2019
Creator: Tozzi, Arturo & Peters, James F.
Object Type: Article
System: The UNT Digital Library
Generation of over 1000 Diffraction Spots from 2D Graded Photonic Super-Crystals (open access)

Generation of over 1000 Diffraction Spots from 2D Graded Photonic Super-Crystals

Discusses a project in which researchers were able to generate over 1000 diffraction spots from a graded photonic super-crystal with a unit super-cell size of 12a × 12a where a is the lattice constant and hole radii are gradually changed in dual directions.
Date: April 10, 2020
Creator: Hassan, Safaa; Jiang, Yan; Alnasser, Khadijah; Hurley, Noah; Zhang, Hualiang; Philipose, Usha et al.
Object Type: Article
System: The UNT Digital Library
High-Throughput Computational Search for Half-Metallic Oxides (open access)

High-Throughput Computational Search for Half-Metallic Oxides

The article describes a high-throughput computational search for half-metallic compounds. The analysis of calculated electronic properties of thousands of materials from the inorganic crystal structure database allowed the authors to identify potential half metals. They found over two-hundred strong half-metallic oxides; several of them have never been reported before.
Date: April 25, 2020
Creator: Liyanage, Laalitha S. I.; Slawińska, Jagoda; Gopal, Priya; Curtarolo, Stefano; Fornari, Marco & Buongiorno Nardelli, Marco
Object Type: Article
System: The UNT Digital Library
The XMM-SERVS survey: new XMM–Newton point-source catalogue for the XMM-LSS field (open access)

The XMM-SERVS survey: new XMM–Newton point-source catalogue for the XMM-LSS field

This article presents an X-ray point-source catalogue from the XMM-Large Scale Structure (XMMLSS) survey region, one of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields.
Date: April 25, 2018
Creator: Chen, C. -T. J.; Brandt, William Nielsen; Luo, Bin; Ranalli, P.; Yang, G.; Alexander, David M. et al.
Object Type: Article
System: The UNT Digital Library