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Pointed magnetic elements are introduced as an improvement upon rectangular strips currently employed in composite element magnetic barcodes. The coercivity of these elements, as measured using the magneto-optic Kerr effect, is found to strictly adhere to a single power law relationship with the element width, where the power law exponent is dependent on the length of the pointed region and takes values between − 0.98 and − 0.91. The steeper gradients here, along with the absence of the crossover region seen in rectangular devices, present these structures as a strict improvement in terms of potential device applications. These improvements are found to be present for all structures where the pointed region is as long as, or longer than, the magnetic element is wide. The remanent magnetization configuration, imaged using photo-emission microscopy with contrast from x-ray magnetic circular dichroism (XMCD-PEEM), is compared to the results of micromagnetic simulations. It is found to cant inward in the pointed section of the strip, aligning with the edges of the point, pinning the magnetization and giving a consistent magnetization reversal behavior for all element widths investigated. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) titanium disulfide (TiS 2) is the lightest transition-metal dichalcogenide (TMD). It exhibits relatively better adsorption and diffusion of sodium (Na) and potassium (K) ions than other TMDs, such as MoS 2 (molybdenum disulfide) and ReS 2 (rhenium disulfide), making it a promising anode material for alkali-ion batteries. Previous studies have found that doping significantly enhances the adsorption and diffusion capabilities of 2D TMDs. For the first time, this work reports the adsorption of Na and K ions on doped TiS 2 monolayers using first-principles calculations, where the Ti atom is substituted by 3d-transition metals, including iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu). Metal-atom doping induces remarkably stronger binding of alkali ions on the surface of TiS 2 , with adsorption energies ranging from − 2.07 to − 2.48 eV for Na and − 2.59 to − 3.00 eV for K. The diffusion barrier energies for alkali ions decrease in the proximity of the doping site and increase as the ions travel away from the doping site for Fe-, Co-, and Ni-doped TiS 2. The average open circuit voltage increases dramatically when Na ions are adsorbed on Fe-doped TiS 2 (by 62%) and Co-doped TiS 2 (by 61%), while K ions result in a moderate improvement of 9% and 8%, respectively. These findings suggest that metal-atom doping considerably improves the electrochemical properties of 2D TiS 2 , potentially enabling its use as anode materials in Na- and K-ion batteries. [ABSTRACT FROM AUTHOR]

The thermophysical properties of liquid Zr–V alloys covering a whole composition range were systematically measured by an electrostatic levitation technique. A series of maximum undercoolings from 150 to 386 K (0.2 TL) was achieved for 11 different liquid alloys under containerless state and radiative cooling conditions, where Zr83.5V16.5 and Zr20V80 alloys displayed the strongest undercooling ability. The densities of liquid Zr–V alloys were measured over a wide temperature range from overheated to undercooled states, and the results exhibited a linear dependence on temperature for all 11 compositions. Two typical solidification pathways were observed for hypoeutectic alloys. Except for a slowing down of decreasing tendency near a eutectic Zr57V43 alloy, the liquid densities of Zr–V alloys almost decrease linearly with increasing V content. Accordingly, the thermal expansion coefficients of Zr–V alloys were also derived from containerless measurements, and they showed an increasing tendency with V content. Since thermal radiative dominated the heat transfer process, the ratio of isobaric specific heat to hemispherical emissivity was directly deduced from the thermal balance equation, leading to a quadratic relationship with temperature. It was found that the increase of V content enhanced the ability of radiative heat dissipation below 16.5 at. % V content. [ABSTRACT FROM AUTHOR]

In this paper, mesoporous nitrocellulose (NC)/graphene oxide (GO) composite aerogel is manufactured by a sol-gel method followed by supercritical carbon dioxide drying. The effects of GO on the microstructure, decomposition, and thermal conductivity are studied. The laser absorption, laser ignition property, and combustion performance of NC aerogel and NC/aerogel are also investigated. The results indicate that NC/GO aerogel is established by the combination of NC nano-fibers and GO sheets, and the aerogels are mesoporous with average pore size at 40 nm. Moreover, the thermal stability of aerogels is decreased by the nano-structure of NC, and the laser absorption is significantly increased by the nano-porous structure and the adoption of GO. In addition, the laser ignition and combustion efficiency are also greatly improved by the nano-porous aerogel structure and the incorporation of evenly uniformly dispersed GO sheets with high photothermal conversion efficiency and thermal conductivity. Laser ignition times reduced by 73.7% and 99.6% are obtained, and flame propagation rates up to 4.7 and 12.3 times are observed for NC aerogel and NC/5 wt. % GO aerogel, respectively. [ABSTRACT FROM AUTHOR]

The efficiency of organic light-emitting diodes that utilize the principle of thermally activated delayed fluorescence (TADF) depends sensitively on the host material in which the TADF emitter molecules (guests) are embedded. Potential loss processes are "deconfinement," the transfer of excitons from the guest to the host, and "dissociation," the formation of intermolecular charge-transfer states. We investigate how both processes can be suppressed by studying the photoluminescence efficiency, emission spectrum, and time-resolved emission intensity of eight thin-film systems in which 5 mol. % of the sky-blue TADF emitter 4-carbazolyl-methylphthalimide (abbreviated here as CzPIMe) is embedded in various host materials. Deconfinement is found to be entirely suppressed if the triplet energy of the host is 0.25 eV or more above that of the guest. For systems allowing for deconfinement, the dependence on the energy difference is consistent with a recent theoretical analysis [C. Hauenstein et al., J. Appl. Phys. 128, 075501 (2020)]. Dissociation, due to hole transfer to a host molecule, is found to be suppressed if the host's highest occupied molecular orbital energy is not more than about 0.2 eV higher than that of the guest. Otherwise, we observe an efficiency loss, a spectral redshift, and the disappearance of distinct prompt and delayed emission regimes. A comprehensive rate-equation model is developed from which we study the sensitivity of these observations to the energy level structure, the intermolecular interaction rates, and the photophysical rates that follow from a fit to the experimental data for the CzPIMe:TCTA[ tris (4 - carbazoyl - 9 - ylphenyl) amine ] system. [ABSTRACT FROM AUTHOR]

In this study, a 300 °C-annealed 3 × 4 V/ZnO multilayer structure demonstrates the lowest resistivity (3.82 × 10−3 Ω cm) and the highest mobility (18 cm2/V s) among the studied V/ZnO multilayer structures. By measuring the energy bandgap (Eg), work function (Φ), and electron affinity (χ) by ultraviolet photoelectron spectroscopy and photoluminescence analysis, the corresponding energy band diagram at the ZnVxOy/ZnO interface can be constructed. A potential is observed at the ZnVxOy/ZnO interface, which induces the two-dimensional electron gas (2DEG) effect, and this is attributed to the high-mobility conduction path. The potential well directly relates to the Φ difference between the ZnO and ZnVxOy layers, which is determined to be 0.22, 0.46, and −0.1 eV for the as-deposited, 300 °C-annealed, and 500 °C-annealed V/ZnO multilayer structures, respectively. The 300 °C-annealed V/ZnO multilayer structure could possibly have the largest depth in the potential well. This supports the 2DEG mechanism for the high mobility of the 300 °C-annealed V/ZnO multilayer structure. [ABSTRACT FROM AUTHOR]