DFT study of the half-metallic variant perovskites A2OsX6 (A = Rb/Cs; X = Cl/Br) for spintronic and thermoelectric applications

We present our results of the spin-polarized calculations on the structural, magneto-electronic, thermodynamic, and thermoelectric properties of vacancy-ordered double perovskites A₂OsX₆ (A = Rb/Cs; X = Cl/Br). We utilized the Wu-Cohen generalized gradient approximation (Wu-GGA) and the mBJ scheme to determine a more reliable electronic structure. The compounds exhibit negative formation energy, suitable tolerance factor, and a stable phonon spectrum, indicating their stability. The compounds show half-metallicity, acting as semiconductors with direct band gaps between 2 and 3 eV in the spin-up orientation while metallic in the spin-down. Each compound shows a total spin magnetic moment of 2.00 μB per formula unit, with Os-t²g states contributing the most (~1.5 μB). The computed thermoelectric coefficient indicates the usability of these compounds across a wide temperature range (200–800 K) with high electrical conductivity and low electronic thermal conductivity. The compounds exhibit high Seebeck coefficient and figure of merit (ZT), making them suitable for thermoelectric applications. With ferromagnetic and half-metallic characteristics, these compounds could be promising candidates for spintronics, thermoelectronic, and data storage applications.     

A 14 Parameter Study of UHPLC’s for Method Development Transfer and Troubleshooting

Five ultra-high pressure liquid chromatography (UHPLC) instruments were compared to one another by examining the overall system performance and key functions of the system parts including: pump, auto-sampler, thermo-stated column compartment, and the detector. The five UHPLC systems used in this study were: ThermoFisher Vanquish, Agilent 1290 Infinity I, Agilent 1290 Infinity II, Waters Acquity I-Class, and Shimadzu Nexera X2. The identities of the systems were blinded in the results and discussion section to use this study for scientific purposes only rather than for competition and marketing. The following tests were performed to evaluate and compare the five UHPLC systems: injector linearity and precision, sample carryover, sample (autosampler) temperature accuracy, column temperature accuracy and precision, pressure ripple, pump mixing accuracy, flow rate accuracy, detector drift and noise, detector linearity, wavelength accuracy, extra-column volume, and dwell volume determination. This study presents an approach on how to test the performance of UHPLC systems along with potential problems that analysts may face when using the UHPLC systems, examples of such issues are: retention time irreproducibility, low sensitivity, method transfer failure, etc.     

On pseudo-continuities in the eigenvalue continuum of one-speed neutron transport theory

We report on a new closed-form approximant to the singular eigenfunction transient solution of the one-speed, one-dimensional neutron transport equation with an anisotropic scattering kernel. It is proved that the associated eigenvalue continuum must be pointwise perforated.     

On the Marchenko System and the Long-time Behavior of Multi-soliton Solutions of the One-dimensional Gross-Pitaevskii Equation

We establish a rigorous well-posedness results for the Marchenko system associated to the scattering theory of the one dimensional Gross-Pitaevskii equation (GP). Under some assumptions on the scattering data, these well-posedness results provide regular solutions for (GP). We also construct particular solutions, called Nsoliton solutions as an approximate superposition of traveling waves. A study for the asymptotic behaviors of such solutions when t → ± ∞ is also made.     

Nodal adjoint method for multigroup diffusion in heterogeneous slab reactors

A variational adjoint nodal method is proposed to yield an approximation theory for the eigenvalues of the multigroup neutron diffusion boundary value problem of a heterogeneous quasicritical one-dimensional slab reactor. Semianalytical eigensolutions are constructed for the associated whole-reactor group nodal fluxes. The method appears to be mathematically more consistent, computationally more straightforward, and practically more convenient than alternative nodal or finite element schemes. © 1992 John Wiley & Sons, Inc.     

Photocrosslinking of elastomer systems. I. UV light-induced reactions in a blend of EPDM-benzoin derivatives

Photocrosslinking experiments were performed on elastomeric polymer films (EPDM) that contained benzoin derivatives as photosensitive initiators. Infrared (IR) and ultraviolet (UV) spectroscopy investigations were used in conjunction with physical property measurements. The results all together make it possible to discuss the crosslinking mechanism and pose interesting questions about the reactivity of benzoin derivatives in their excited states in relation to their efficiency in the crosslinking process.     

Fresnel phase matching: a universal phase matching scheme

We present new theoretical concepts for Fresnel phase matching. A guided wave approach is described, which allows us to intrinsically take into account all the physical processes involved. To cite this article: M. Raybaut et al., C. R. Physique 8 (2007).     

Determining the absolute, chemical-heterogeneity-corrected molar mass averages, distribution, and solution conformation of random copolymers

We present a method by which to obtain the absolute, chemical-heterogeneity-corrected molar mass (M) averages and distributions of copolymers and apply the method to a gradient random copolymer of styrene and methyl methacrylate in which the styrene percentage decreases from approximately 30% to 19% as a function of increasing molar mass. The method consists of separation by size-exclusion chromatography (SEC) with detection using multi-angle static light scattering (MALS), differential viscometry (VISC), differential refractometry (DRI), and ultraviolet absorption spectroscopy (UV) and relies on the preferential absorption of styrene over methyl methacrylate at 260 nm. Using this quadruple-detector SEC/MALS/UV/VISC/DRI approach, the percentage of styrene (%St) in each elution slice is determined. This %St is then used to determine the specific refractive index increment, corrected for chemical composition, at each elution slice, which is then used to obtain the molar mass at each slice, corrected for chemical composition. From this corrected molar mass and from the chemical-composition-corrected refractometer response, the absolute, chemical-heterogeneity-corrected molar mass averages and distribution of the copolymer are calculated. The corrected molar mass and intrinsic viscosity at each SEC elution slice are used to construct a chemical-heterogeneity-corrected Mark–Houwink plot. The slice-wise-corrected M data are used, in conjunction with the MALS-determined R _G,z of each slice, to construct a conformation plot corrected for chemical heterogeneity. The corrected molar mass distribution (MMD) of the gradient copolymer extends over an approximately 30,000 g/mol wider range than the uncorrected MMD. Additionally, correction of the Mark–Houwink and conformation plots for the effects of chemical heterogeneity shows that the copolymer adopts a more compact conformation in solution than originally concluded.     

On topological properties of hierarchical interconnection networks

There is really a lot of mathematics involved in electrical and electronic engineering. It depends on what area of electrical and electronic engineering, for example there is a lot more abstract mathematics in communication theory and signal processing and networking etc. Networks involve nodes communicating with each other. A lot of computers linked together form a network. Cell phone users form a network. Networking involves the study of the best way of implementing a network. Graph theory has found a considerable use in this area of research. In this paper, we extend this study to interconnection networks and derive analytical closed results of general Randi? index \(R_{\alpha }(G)\) for different values of “\(\alpha \)” for block shift network (BSN-1) and (BSN-2), Hierarchical hypercube (HHC-1) and (HHC-2). We also compute first Zagreb, \(\textit{ABC}\), \(\textit{GA}\), \(\textit{ABC}_{4}\) and \(\textit{GA}_{5}\) indices and give closed formulae of these indices for Hierarchical interconnection networks.