Activity

The low-coordinated sites of electrocatalysts favour hydrogen evolution, while the edge sites are active for CO2 reduction. Oleylamine is used to stabilize nanoparticles by adsorbing on the low-coordinated sites. The hydrogen evolution reaction was dramatically suppressed and the FECO remained >93% from -0.4 to -0.8 V (vs. RHE) when oleylamine ligands existed on the surface of a gold catalyst. More H+ and electrons were involved in the CO evolution reaction, which changed the rate-limiting step from single-electron transfer to the chemical reaction step. The results establish that the surface-adsorbed surfactants during catalyst synthesis have an important effect on CO2 electrocatalytic reduction.With an aim towards the design of efficient and straightforward fluorescent probes for hydrazine, the synthesis of (2-acetoxyaryl) methylene diacetate derivatives (1-4) was carried out by reacting substituted aromatic α-hydroxy aldehydes with acetyl chloride and sodium acetate in excellent yields. As a preliminary investigation, the ability of probe 1 was examined for the detection of substituted aliphatic and aromatic amines, amino acids, and other ions in Britton-Robinson buffer solution (50 mM, water/ethanol v/v of 99/1 at pH 7.4). Probe 1 selectively exhibited an intense blue fluorescence with hydrazine in less than 2 minutes, whereas light green or no fluorescence was noticed with substituted amines and amino acids. Among all the probes employed (1-4) in the present study, probes 1 and 2 were found efficient towards the rapid detection of hydrazine. Furthermore, the fluorescence sensing ability of probes 1 and 2 was tested not only under varying pH conditions but also by varying water-fraction from 0-99%. Moreover, the detection limits of hydrazine using 1 and 2 were found as 8.4 and 8.7 ppb, respectively, which is less than the acceptable limit as per the standards of the US Environment Protection Agency. In this contribution, the probes 1 and 2 demonstrate rapid, selective, sensitive, and ratiometric detection of highly toxic hydrazine by OFF-ON fluorescence switch in water samples as well as living cells.This study examines the shear-induced formation of fibrillar form II crystals and subsequent form II to I transformation of an isotactic polybutene-1 sample through a combination of rheology, polarized optical microscopy (POM), and small- and wide-angle X-ray scattering (SAXS and WAXS) measurements. selleck Strong shear flow was applied using a strain-controlled rheometer with parallel plate geometry, for which the shear rate increases linearly from the center to the perimeter. Highly oriented crystals were created by the shear flow, leading to the birefringent region shown in the POM images, which propagated from the perimeter to the center with increasing applied shear rate. The form II to I transformation, traced by WAXS, was greatly accelerated with increasing shear rate. This trend is explained as being due to the formation of fibrillar crystals and accordingly a large amount of highly oriented chains tethered between the crystal lamellae. The stress sustained by these tethered chains facilitates the nucleation of form I thereby accelerating the form II to I transformation.Highly efficient scintillation crystals with short decay times are indispensable for improving the performance of numerous detection and imaging instruments that use- X-rays, gamma-quanta, ionising particles or neutrons. Halide perovskites emerged recently as very promising materials for detection of ionising radiation that motivated further exploration of the materials. In this work, we report on excellent scintillation properties of CsPbBr3 crystals when cooled to cryogenic temperatures. The temperature dependence of luminescence spectra, decay kinetics and light yield under excitation with X-rays and α-particles was investigated. It is shown that the observed changes of spectral and kinetic characteristics of the crystal with temperature can be consistently explained by radiative decay of free excitons, bound and trapped excitons as well as electron-hole pairs originating from their disintegration. It has been found that the crystal exhibits a fast decay time constant of 1 ns at 7 K. The scintillation light yield of CsPbBr3 at 7 K is assessed to be 50,000 ± 10,000 ph/MeV at excitation with 12 keV X-rays and 109,000 ± 22,000 ph/MeV at excitation with α-particles of 241Am. This finding places CsPbBr3 in an excellent position for the development of a new generation of cryogenic, efficient scintillation detectors with nanosecond response time, marking a step-change in opportunities for scintillator-based applications.Vibration is a major concern in coal mining with a shearer, and an accurate model that allows complex responses can analyze the overall vibration of the system. The large load impact on and severe vibration of a coal shearer under operating conditions were considered. A numerical model was proposed for characterizing the nonlinear dynamics of the shearer traction-swing coupling in 13 degrees of freedom using vibration mechanics and multibody dynamics. Particularly, the contact between the shearer sliding shoe and scraper conveyor was characterized using three-dimensional fractal theory, the gapped contact between the driving wheel and base plate was characterized using Hertz contact theory, and the rigidity of the lift cylinder, the coupling between the shearer fuselage and haulage unit, and the rigidity of the shearer ranging arm were characterized using Hooke’s law. Using experimentally corrected drum loads as the external excitation, the numerical model was resolved to characterize and analyze the dynamical responses of critical shearer components. The numerical model was validated against the vibration responses of a shearer and its critical components under different operating conditions obtained from a mechanical test.The research results provide theoretical basis for the structure optimization and process parameter optimization of the shearer.Cells comprise mechanically active matter that governs their functionality, but intracellular mechanics are difficult to study directly and are poorly understood. However, injected nanodevices open up opportunities to analyse intracellular mechanobiology. Here, we identify a programme of forces and changes to the cytoplasmic mechanical properties required for mouse embryo development from fertilization to the first cell division. Injected, fully internalized nanodevices responded to sperm decondensation and recondensation, and subsequent device behaviour suggested a model for pronuclear convergence based on a gradient of effective cytoplasmic stiffness. The nanodevices reported reduced cytoplasmic mechanical activity during chromosome alignment and indicated that cytoplasmic stiffening occurred during embryo elongation, followed by rapid cytoplasmic softening during cytokinesis (cell division). Forces greater than those inside muscle cells were detected within embryos. These results suggest that intracellular forces are part of a concerted programme that is necessary for development at the origin of a new embryonic life.