Constructing type-II heterojunctions is an effective way to enhance the photoelectrochemical (PEC) performance of semiconductor-based materials. In this study, in order to increase the specific surface area, a novel coral-like 3D porous Ta3N5 nanostructure was first synthesized via a hydrothermal method. Subsequently, CdS quantum dots were deposited on the coral-like Ta3N5 substrate by a successive ionic layer adsorption and reaction method with 40, 80, and 120 cycles (named Ta3N5/CdS-40, Ta3N5/CdS-80, and Ta3N5/CdS-120) to modulate the band structures and optical absorption properties of the composites. The results show that Ta3N5/CdS-80 exhibits a continuous and dense CdS overlayer with effectively passivated surface states, delivering the optimal PEC performance (3625 mu A & centerdot;cm(-2) at +1 V about 39 times that of the pure Ta3N5). This is because the Type-II heterojunction between CdS and Ta3N5 facilitates the separation of photogenerated carriers, and the high-quality CdS coating reduces the capture of photogenerated carriers by defects. When coupled with 304 stainless steel, Ta3N5/CdS-80 yields a photovoltage drop of 0.39 V and a net photocurrent density of 99.39 mu A & centerdot;cm(-2), significantly outperforming the Ta3N5/CdS-40 and Ta3N5/CdS-120 samples. This work provides experimental evidence for the development of superior Ta3N5-based photogenerated cathodic protection materials.
In this study, 6-(cyclopropanesulfonamido)-N-(2-ethylphenyl)imidazo[1,2-b] pyridazine-2-carboxamide (1) was synthesized through five steps. The structure was identified by 1H NMR,13C NMR, MS, FT-IR and SC-XRD. Theoretical calculations were carried out using the DFT/B3LYP method with the 6-311 + G(2d, p) basis set. Based on this approach, the molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), vibrational properties, and Hirshfeld surface analysis of compound 1were investigated and analyzed to elucidate its physicochemical characteristics. Subsequently, integrated analysis of molecular docking, in vitro cellular activity assays and in silico ADME property predictions demonstrated that compound 1 exhibits potential inhibitory and biological activity.
Thin films of (La0.06Ga0.94)2O3:Eu3+ were obtained by radio-frequency ion-plasma sputtering in an argon atmosphere on amorphous upsilon-SiO2 substrates. XRD analysis revealed that the freshly deposited films have an amorphous structure, whereas heat treatment in argon leads to the formation of a polycrystalline structure in the films. Atomic force microscopy was used to study the morphology of the film surface and determine the parameters of the grains that form the film surface. The results of studies of the photoluminescence and cathodoluminescence of the studied films are presented. It is shown that thin films ((La0.06Ga0.94)2O3:Eu emit in the blue region of the spectrum upon photoexcitation, and this luminescence is caused by the luminescence of the (La0.06Ga0.94)2O3 matrix. Under cathodic excitation, the activator luminescence of Eu3+ ions caused by 5D0 -> 7FJ (J = 0, 1, 2, 3, 4) electronic transitions is observed. The wavelength of the emission maximum is 613 nm, which corresponds to red luminescence.
Solar Ultraviolet (UV) radiation reaching the Earth's surface has significant impacts on the environment including agriculture crops, rangeland grasses, and forests. Reductions in UV-absorbing stratospheric ozone resulting from climate change and the anthropogenic emission of ozone depleting substances raised concerns regarding future levels of surface UV radiation. Responding to this potential threat, the U.S. Department of Agriculture established the UV-B Monitoring and Research Program (UVMRP) in 1992. There are three primary goals in UVMRP: (1) to monitor surface-level solar UV and visible radiation across the U.S.; (2) to investigate the effects of UV and other environmental stressors on economically important crops through experiments; and (3) to provide science-informed decision support toward sustainable U.S. agriculture by developing the coupled Climate-Agroecosystem-UV Interactions and Economic impacts (CAIE) modelling framework.
We demonstrate narrow-linewidth continuous-wave operation of a compact slab-based Ho:YAG laser incorporating custom volume Bragg gratings (VBGs) centered at 2090 nm. Stable single-line lasing was achieved; however, power scaling was limited by thermal loading in the VBGs, caused by substrate heating and a spectral mismatch between the VBG design wavelength (2090 nm) and the Ho:YAG gain peak (similar to 2097 nm) under cryogenic cooling. This mismatch arises because the VBG reflection wavelength was fixed at room-temperature design conditions, whereas under cryogenic cooling the Ho:YAG gain spectrum shifts toward the zero-phonon transition near 2097 nm due to depopulation of higher Stark sub-levels. Room-temperature operation reduced the thermal load, enabling 17 W of stable output with 45 % slope efficiency and excellent beam quality. Thermoelectric cooling further improved spectral stability, yielding similar to 0.2 nm linewidth emission suitable for incoherent LiDAR.
