Blantonbengtson0618

Phosphors with a rigid and symmetrical structure are urgently needed. The alkali lithosilicate family (A[Li3SiO4]) has been extensively studied with a narrow emission band due to its unique cuboid-coordinated environment and rigid structure. However, here we demonstrate for the first time Ce-doped NaK2Li[Li3SiO4]4 phosphors with a broad emission band, a high internal quantum efficiency (85.6%), and excellent thermal stability. Photoluminescence indicates the Ce's preference to occupy the Na+ site, leading to a strong blue color emission with peak maxima at 417 and 450 nm. Temperature- and pressure-dependent photoluminescence reveals thermal stability and a phase transition. Moreover, the X-ray absorption near-edge structure reveals the mixing of Ce3+ and Ce4+ in the materials; this result differs from that of Eu2+-doped A[Li3SiO4] phosphors. The charge compensation process is then proposed to explain this difference. This study not only provides insights into Ce-doped UCr4C4-type phosphors but also explains the charge compensation mechanism of the aliovalent doping process.Alloying is one of the most promising routes for tuning the physicochemical properties of noble metal-based nanocatalysts and thus improving their (electro)catalytic performance. Despites numerous achievements, bimetallic and trimetallic nanoalloys have still been thoroughly studied for the past two decades. In this study, metalloid boron (B) was alloyed within palladium (Pd)-based nanocatalysts to promote the electrochemical ethanol oxidation reaction (EOR) in alkaline media. The optimum PdCuB nanocatalyst exhibited remarkable electrochemical EOR activity (5.83 A mgPd-1) and good operation stability (both cycling and chronoamperometric studies). Mechanistic studies in both pure KOH and a KOH/ethanol mixture attributed superior EOR performance to positive synergistic effects of B in Pd-based nanocatalysts that kinetically accelerated the removal of poisoning ethoxy intermediates (the rate-determining step of EOR). They included (i) an electronic effect that changed the electronic structure of Pd and thus weakened the adsorption of poisoning ethoxy intermediates, (ii) a bifunctional effect that facilitated the adsorption of OHads and thus kinetically accelerated the further oxidation of poisoning intermediates, and (iii) a structural effect in which smaller B interstitially inserted into Pd-based nanocrystals and thus suppressed the physical Ostwald ripening processes.In situ X-ray photoelectron spectroscopy is applied to electrochemical lithiation/delithiation processes of an amorphous Si electrode sputter-deposited on a Li6.6La3Zr1.6Ta0.4O12 solid electrolyte. After the first lithiation, a broad Li peak appears at the Si surface, and peaks corresponding to bulk Si and Si suboxide significantly shift to lower binding energy. The appearance of the Li peak and shift of the Si peaks confirm the formation of lithium-silicide and lithium-silicates due to the lithiation of Si and native suboxide. The composition of lithium-silicide is estimated to be Li3.44Si by quantitative analysis of electrochemical response and photoelectron spectra. Peak fitting analysis shows the formation of Li2O and Li2CO3 due to side reactions. Upon the following delithiation, the peak corresponding to Li3.44Si phase shifts back to higher binding energy to form Li0.15Si phase, while lithium-silicates, Li2O, and Li2CO3 remained as irreversible species. Thus, electrochemical reactions accompanied with lithiation/delithiation processes are successfully observed.The time scale associated with shock-induced detonation is a key property of energetic materials that remains poorly understood. Herein, we test aspects of one potential mechanism, the phonon up-pumping mechanism, where shock compression excites lattice phonon modes, transferring energy to intramolecular vibrations leading to chemical bond cleavage and reaction. Using ultrafast infrared pump-probe spectroscopy on pentaerythritol tetranitrate (PETN), we reveal sub-picosecond vibrational energy transfer (VET) from the photoexcited band at 1660 cm-1 into every other infrared-active mode in the probed frequency range 800-1800 cm-1. Energy transfer processes remain incomplete at 150 ps. Computational predictions from density functional theory are used in tandem to elucidate VET pathways in PETN.The COVID-19 pandemic is an urgent global health emergency, and the presence of Furin site in the SARS-CoV-2 spike glycoprotein alters virulence and warrants further molecular, structural, and biophysical studies. Here we report the structure of Furin in complex with SARS-CoV-2 spike glycoprotein, demonstrating how Furin binds to the S1/S2 region of spike glycoprotein and eventually cleaves the viral protein using experimental functional studies, molecular dynamics, and docking. The structural studies underline the mechanism and mode of action of Furin, which is a key process in host cell entry and a hallmark of enhanced virulence. Our whole-exome sequencing analysis shows the genetic variants/alleles in Furin were found to alter the binding affinity for viral spike glycoprotein and could vary in infectivity in humans. Unravelling the mechanisms of Furin action, binding dynamics, and the genetic variants opens the growing arena of bona fide antibodies and development of potential therapeutics targeting the blockage of Furin cleavage.The growth of aerosol particles in the atmosphere is related to chemical reactions in the gas and particle phases and at aerosol particle surfaces. While research regarding the gas and particle phases of aerosols is well-documented, physical properties and chemical reactivities at aerosol particle surfaces have not been studied extensively but have long been recognized. In particular, in situ measurements of aerosol particle surfaces are just emerging. The main reason is a lack of suitable surface-specific analytical techniques for direct measurements of aerosol particles under ambient conditions. Here we develop in situ surface-specific electronic sum frequency scattering (ESFS) to directly identify spectroscopic behaviors of molecules at aerosol particle surfaces. see more As an example, we applied an ESFS probe, malachite green (MG). We examined electronic spectra of MG at aerosol particle surfaces and found that the polarity of the surfaces is less polar than that in bulk. Our quantitative orientational analysis shows that MG is orientated with a polar angle of 25°-35° at the spherical particle surfaces of aerosols.