A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk.

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk

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Citrate combustion synthesized Al-doped CaCu3Ti4O12 quadruple perovskite: synthesis, characterization and multifunctional properties

The facile synthesis of the Al-doped CaCu3Ti4O12 quadruple perovskite, a well-known and vastly studied material for various technological applications, using the modified citrate combustion route along with structural, microstructural, and X-ray photoelectron spectroscopic (XPS) characterization and magnetic, dielectric and electrical properties has been investigated and reported here. The possible applications of the material as a Schottky barrier diode (SBD) in optoelectronic devices and as a catalyst in methanol steam reforming (MSR) reaction for hydrogen generation, hitherto unreported in the open literature, have also been explored. The compound is crystallized in the cubic body centered Im[3 with combining macron] space group and the particle size is found to be in nanodimension with rather narrow size distribution. The enhanced resistivity could be attributed to the grain boundary effect, and consequently, it exhibits better performance as a SBD compared to the undoped sample. Desired cationic composition with expected valence states within the probe range is confirmed by XPS analysis. A better catalytic activity towards MSR is noticed for the Al-doped CaCu3Ti4O12 compared to the undoped composition. These new findings, namely MSR activity and applicability in the Schottky device, have highlighted further the multifunctional nature of the material in energy related issues and would thus be of interest to the materials community searching for functional materials

Facile synthesis of CuCr2O4/BiOBr nanocomposite and its photocatalytic activity towards RhB and tetracycline hydrochloride degradation under household visible LED light irradiation.

Here we report the development of CuCr2O4/BiOBr nanocomposite photocatalysts for the first time to serve the purpose of rhodamine B (RhB) and tetracycline hydrochloride (TC-HCl) degradation using household visible light emitting diode (LED) light. In this nanocomposite, sol-gel combustion made spherical shaped CuCr2O4 nanoparticles are decorated on BiOBr plates in single pot via precipitation method using cetyltrimethylammonium bromide (CTAB) as the Br source as well as the template. The present investigation highlights a significant advancement to tackle the challenge of visible light induced photocatalytic degradation of harmful organic dye RhB and antibiotic-pollutant TC-HCl. The 20%CuCr2O4/BiOBr nanocomposite exhibits high degradation activity for both RhB (96.0% in 15 min) and TC-HCl (96.7% in 300 min) in presence of LED light with good recycling characteristics. Detailed structural and optical characterization using XRD, BET, FESEM, TEM, HRTEM, EDX, XPS, UV−Vis DRS, PL spectroscopy and Raman spectroscopy have been carried out prior performing photocatalytic activity tests. The structural as well as optical data have revealed a significant improvement in visible light absorption of BiOBr in presence of CuCr2O4. Based on energy band modification at the heterojunction of nanocomposite materials and their radical trapping ability, a plausible mechanistic path of photocatalytic degradation is presented