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Measurement of magnetic field in this layer is challenging both from point of view of observations and interpretation of the data. We present in this work about spectropolarimetric observations of a pore, simultaneously in Ca ii (CaIR) at 854.2 nm (CaIR) and H α (656.28 nm). The observed region includes a small scale energetic event (SSEE) taking place in the region between the pore and the region which show opposite polarity to that of pore at the photosphere. The energetic event appears to be a progressive reconnection event as shown by the time evolution of the intensity profiles. Closer examination of the intensity profiles from the downflow regions suggest that the height of formation of CaIR is higher than that of Hi α, contrary to the current understanding about their height of formation. Preliminary results on the inversion of Stokes-I and V profiles of CaIR are also presented. [ABSTRACT FROM AUTHOR]

For a more precise modeling of polarized spectral lines formed in extended and expanding stellar atmospheres, the solution of the radiative transfer equation for the Stokes vectors must be obtained in a spherical geometry rather than in a planar geometry. In this paper, we present the modern iterative techniques based on operator perturbation to solve the spherically symmetric polarized radiative transfer equation with velocity fields. We consider scattering on a two-level atom and account for partial frequency redistribution. An accurate numerical solution to such problems requires the use of spatial grids with higher resolution. Consequently, Jacobi-based methods lead to slower convergence rate. The convergence rate can be improved by a factor of 2 or more when fast iterative schemes based on Gauss–Seidel (GS) and successive overrelaxation (SOR) methods are used over the Jacobi-based method. Here we present the Jacobi, GS, and SOR iterative techniques for solving the abovementioned problem, and discuss their convergence behavior. [ABSTRACT FROM AUTHOR]

Measurement of magnetic field in this layer is challenging both from point of view of observations and interpretation of the data. We present in this work about spectropolarimetric observations of a pore, simultaneously in Ca ii (CaIR) at 854.2 nm (CaIR) and H α (656.28 nm). The observed region includes a small scale energetic event (SSEE) taking place in the region between the pore and the region which show opposite polarity to that of pore at the photosphere. The energetic event appears to be a progressive reconnection event as shown by the time evolution of the intensity profiles. Closer examination of the intensity profiles from the downflow regions suggest that the height of formation of CaIR is higher than that of Hi α, contrary to the current understanding about their height of formation. Preliminary results on the inversion of Stokes-I and V profiles of CaIR are also presented. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ti doped CdO is firstly reported for electrochemical non-enzymatic H 2 O 2 sensor applications. • Fabricated nanostructured thin films were directly exploited as working electrodes toward the detection of harmful H 2 O 2 gas. • Ti: CdO film exhibits pronounced electrocatalytic activity for the reduction of H 2 O 2 when compared to pure CdO. Abstract A new material, Ti doped CdO (Ti: CdO) semiconductor, is firstly reported by this work for electrochemical non-enzymatic hydrogen peroxide (H 2 O 2) sensor applications which was deposited by a simple, versatile and cost-effective chemical spray pyrolysis method on indium doped tin oxide (ITO) substrate. In the basic studies, first, the withstanding of cubic crystal phase along with worthy crystalline nature is discerned on CdO film after Ti doping, here only the preferentially orientated (200) diffraction plane shifted to (111). Subsequently, the irregular spherically shaped CdO nanoparticles (NPs) morphology changed as nearly uniform size with Ti doping is noticed under thermal pyrolytic decomposition process. The existence of Ti atoms in Ti: CdO film is authentically identified and confirmed using EDX and XPS studies respectively. The absorption and emission properties of CdO and Ti: CdO films are studied and confirmed their narrow band gap nature. Importantly, the Ti: CdO film shows pronounced electrocatalytic activity for the reduction of hydrogen peroxide (H 2 O 2) than pure CdO. Hence, the non-enzymatic electrochemical sensing of Ti: CdO electrode shows a lower detection limit, broad linear range, rapid response time and high sensitivity toward H 2 O 2 detection. This result will boost exploring a new opportunity for the deposition of other metal oxides and semiconductors by using a simple chemical spray pyrolysis method for detection of non-enzymatic H 2 O 2 sensor applications. [ABSTRACT FROM AUTHOR]

Abstract Quaternary Cu 2 ZnSnS 4 (CZTS) thin films with different S/(Cu+Zn+Sn) molar ratio have been deposited by homemade chemical spray pyrolysis unit. Secondary phase formation in CZTS thin films with respect to various S/(Cu+Zn+Sn) molar ratio was investigated. XRD and micro Raman results revealed that CZTS thin films belongs to kesterite crystal structure with a preferred orientation along (1 1 2) plane. Films deposited at x = 2, 1.72, 1.33 contain binary and ternary phases in addition to CZTS. High purity single phase CZTS was obtained at x = 0.80. The surface morphology of the films is found to be smooth. The optical absorption spectra showed that the absorption coefficient of the CZTS thin films is larger than 104 cm−1 in the visible region and the optical band gap varies from 2.05 eV to 1.45 eV. CZTS thin films were used as a photocatalyst to examine the effect of secondary phases in the decolorization of the Rhodamine B (RhB) dye under visible light. It was found that the presence of secondary phase significantly affects the photocatalytic performance of CZTS thin films. [ABSTRACT FROM AUTHOR]

Context. Some post-merger galaxies are known to undergo a starburst phase that quickly depletes the gas reservoir and turns it into a red-sequence galaxy, though the details are still unclear. Aims. Here we explore the pattern of recent star formation in the central region of the post-merger galaxy NGC7252 using highresolution ultraviolet (UV) images from the UVIT on ASTROSAT. Methods. The UVIT images with 1.2 and 1.4 arcsec resolution in the FUV and NUV are used to construct a FUV-NUV colour map of the central region. Results. The FUV-NUV pixel colour map for this canonical post-merger galaxy reveals a blue circumnuclear ring of diameter ~1000 (3.2 kpc) with bluer patches located over the ring. Based on a comparison to single stellar population models, we show that the ring is comprised of stellar populations with ages ≲300 Myr, with embedded star-forming clumps of younger age (≲150Myr). Conclusions. The suppressed star formation in the central region, along with the recent finding of a large amount of ionised gas, leads us to speculate that this ring may be connected to past feedback from a central super-massive black hole that has ionised the hydrogen gas in the central ~400 ~1:3 kpc. [ABSTRACT FROM AUTHOR]

The pure and Cu-doped CdO thin films with various doping concentrations (0.5 to 2 wt%) were deposited on amorphous glass substrates by a chemical spray pyrolysis technique for hydrogen gas sensor application. The crystallinity, morphology, optical and electrical properties of the CdO thin films were effectively modified by Cu doping. The CdO film exhibited a cubic crystal structure, which is retained after Cu doping with significant changes in the preferential orientation of the crystallographic plane. The SEM and AFM images clearly revealed that the grain size and roughness of the CdO film changed with the Cu doping level. The expected element compositions were initially identified by EDAX and then authentically confirmed by XPS to determine its binding energy states. The optical transmittance and near band edge emission (NBE) bands of the CdO film were significantly decreased by Cu doping level. The minimum resistivity (2.01 × 10−3Ω cm) as well as good mobility (19.5 cm2 V−1 s−1) and maximum carrier concentration (1.98 × 1020 cm−3) were obtained for the 1 and 0.5 wt% Cu-doped CdO thin films. The Cu-doped CdO thin films exhibit better hydrogen gas sensing behaviour than that of pure CdO film. Finally, it is concluded that the maximum sensitivity is vividly achieved for the Cu-doped CdO thin film at 1 wt%. [ABSTRACT FROM AUTHOR]

Transparent conducting cadmium oxide (CdO) and Fe (0.5, 1, 1.5 and 2 wt%) doped CdO thin films were deposited on glass substrate using facile chemical spray pyrolysis technique. The influence of Fe doping on the structural, morphological, optical and electrical properties of CdO thin films were systematically investigated using different characterization techniques such as X-ray diffraction (XRD), atomic force microscope (AFM), UV–vis transmittance and Hall measurement respectively. The XRD patterns clearly reveal the pure and Fe doped CdO films are polycrystalline nature along with cubic crystal structure. AFM images show the roughness of the CdO thin film decreases with respect to Fe doping concentration. The surface structure of the 1 wt% Fe doped CdO film was investigated by X-ray photoelectron spectroscopy (XPS). Optical transmittance of the CdO thin film decreases with increasing of Fe doping concentration. The optical band gap value of the CdO thin film gradually decreases from 2.61 to 2.18 eV with increasing Fe doping concentration. From Hall measurement, the minimum value of resistivity is obtained for (7.67×10 −4 Ω cm) 1 wt% of Fe doped CdO thin film. Finally, the ethanol sensor behaviour was observed using home-built sensor unit. The maximum ethanol gas response of 56.12% is observed for 1 wt% of Fe doped CdO thin films. This result suggests the Fe doped CdO is one of the promising material in sensor applications. [ABSTRACT FROM AUTHOR]