نتایج جستجو برای: uv spectra
تعداد نتایج: 172424 فیلتر نتایج به سال:
The conformation of benzo-18-crown-6-ether (B18C6) and its encapsulation of water molecules in a supersonic beam are investigated by laser induced fluorescence (LIF), UV-UV hole-burning, IR-UV double resonance (IR-UV DR), and resonance-enhanced multiphoton ionization (REMPI) spectroscopy with the aid of density functional theory (DFT) calculations at the B3LYP/6-31+G* level. At least four B18C6...
Nanoparticles of titanium dioxide doped with Fe2+ ions have been synthesized via sol-gel technique using Titanium tetraisopropoxide (TTIP) and ferrous sulphate as a precursors. The synthesized nanopowders were characterized by Powder X-ray Diffraction (PXRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Ultraviolet Visible (UV-Vis) and Photoluminescence (PL) Spectrosco...
BACKGROUND Naturally occurring nanoparticles isolated from English ivy (Hedera helix) have previously been proposed as an alternative to metallic nanoparticles as sunscreen fillers due to their effective UV extinction property, low toxicity and potential biodegradability. METHODS This study focused on analyzing the physicochemical properties of the ivy nanoparticles, specifically, those param...
chemometric techniques in spectral analysis have gained importance in the quality control of the drugs mixtures and pharmaceutical formulations containing two or more drugs with overlapping spectra. since theophylline and etophylline have common chromophore, they cannot be analyzed simultaneously using conventional uv methods. simultaneous spectrophotometric determination of etophylline and th...
The UV-excited laser-induced-fluorescence (UV-LIF) spectra of single atmospheric particles and the three-band integrating-nephelometer elastic scattering of atmospheric aerosol were measured during four approximately 24-h periods on May 2007 in Las Cruces, New Mexico, USA. Aerosol scattering measurements in the nephelometer red channel (50-nm band centered at 700-nm) ranged from around 3e10 tim...
A novel zinc oxide - agar nanocomposite was successfully synthesized using zinc chloride as a precursor. The nanocomposite was prepared using a domestic microwave oven. The prepared nanocomposites have been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and UV- visible spectroscopy. The crystalline properties...
Context. Luminous quasars are known to display a sharp steepening of the continuum near 1100 Å. This spectral feature is not well fitted by current accretion disk models, unless comptonization of the disk emission is invoked. Absorption by carbon crystalline dust has been proposed to account for this feature. Aims. Ton 34 (zq = 1.928) exhibits the steepest far-UV decline (Fν ∝ ν ) among the 183...
Superoxide reacts with catechol in dimethylsulfoxide to form a yellow product. The structure of this product was established by different methods. UV-spectra of the yellow compound corre sponded under all circumstances to those of enzymatically produced 2-hydroxymuconic acid semialdehyde. In the presence of ammonia the product was converted to picolinic acid. The UV spectra, the retention time...
Benzoyl-protected mercaptoacetyltriglycine, a synthetic precursor used in the preparation of Technetium-99m-mercaptoacetyltriglycine, a radiopharmaceutical for renal tubular function and L-cysteine methylester, a small, non-zwitterionic amino acid derivative, were used as capping agents of gold nanoparticles obtained by borohydride reduction method. The capped gold nanoparticles composites were...
In case of Thiocarlidum (1) the thermoanalytical examination showed an endothermic transformation without loss of weight. This occured in samples recrystallized from cold polar solvents and the transformation proved to be non-reversible. The UV and IR spectra of the two samples differed characteristically and X-ray studies showed that the two modifications (in the following aand ßmodifications ...
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