The catalytic activity of large zeolite H-ZSM-5 crystals in methanol (MTO) and ethanol-to-olefins (ETO) conversions was investigated and, using operando UV/Vis measurements, the catalytic activity and deactivation was correlated with the formation of coke. These findings were related to in situ single crystal UV/Vis and confocal fluorescence micro-spectroscopy, allowing the observation of the s...

The compound (n-Bu4N)2Tc2Br8 was prepared by the metathesis of (n-Bu4N)2Tc2Cl8 with HBr (g) in dichloromethane and characterized by X-ray absorption fine structure spectroscopy and UV-vis spectroscopy. Analysis of the data gives a Tc-Tc distance of 2.16(1) A and a Tc-Br distance of 2.48(1) A. The Tc(III) oxidation state was inferred by the position of the edge absorption, which reveals a shift ...

The biological process with the ability to study the shape of particles produced would therefore be a limelight of modern nanotechnology. The bacterial strain Escherichia coli, used for the biosynthesis of silver nanoparticles were investigated. These silver nanoparticles were characterized by means of UV–vis spectroscopy, particle size analyzer. The nanoparticles exhibited maximum absorbance a...

This paper reports on the development of Neural Networks algorithms for tropospheric ozone retrieval from ESA-Envisat SCIAMACHY measurements. We present and discuss some retrieval experiments from UV/VIS simulated data, based upon a combined sensitivity analysis performed with the aid of the UVSPEC radiative transfer model and a neural Extended Pruning procedure. In particular, the role of UV a...

We synthesized poly(isothianaphthene methine)s with chiral alkyl chains in the substituent. Resultant polymers are soluble in THF and CHCl₃. Structure of the polymers was characterized with FT-IR, FT-Raman, and UV-Vis-NIR optical absorption spectroscopy. They showed low-bandgap both in solution and in a form of film. Optical activity of the polymers was confirmed with optical rotatory dispersio...

Precarthamin, a yellow precursor of carthamin, was efficiently isolated from the yellow petals of safflower (Carthamus tinctorius L. ) with Sephadex LH-20 column chromatography and preparative HPLC, and identified with UV-vis and NMR spectrometry. The UV-vis spectrum of precarthamin showed lambda(max) of 238 and 406 nm in MeOH. The molar extinction coefficients of precarthamin at 406 nm in MeOH...

On the basis of in situ MAS NMR technique under flow conditions,1-4 the combined in situ MAS NMR-UV/Vis spectroscopy5 has recently been developed to obtain complimentary information on solid catalysts and, therefore, to better elucidate the mechanism involved in heterogeneous catalysis. While NMR spectroscopy allows the identification of species on the working catalyst in more detail, UV/Vis sp...

UNLABELLED Pure zinc oxide and zinc oxide/barium carbonate nanoparticles (ZnO-NPs and ZB-NPs) were synthesized by the sol-gel method. The prepared powders were characterized by X-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Auger spectroscopy, and transmission electron microscopy (TEM). The XRD result showed that the ZnO and BaCO3 nanocrystals grow independently. The Auger spectroscopy ...

The feasibility of identifying habitat of sulfur fumigated Radix Astragali and of determining its sulfur dioxide residue using UV-vis and short wave near-infrared diffuse reflectance spectra coupled with chemometrics was first investigated. The results show that by using UV-vis-SWNIR DRS combined with PCA, the habitat of Radix Astragali is identified definitely, whether it is sulfur-fumigated, ...

In a field experiment, the effect of enhanced UV-B radiation (simulating 20% ozone depletion at Allahabad, 20 degrees 47' N latitude) was studied on two cultivars of Vigna radiata L. with various levels of mineral nutrients (N and P). Study showed decrease in total biomass accumulation, harvest index, RSR and yield after exposure with enhanced level of UV-B. RGR and CGR also showed decline afte...