نتایج جستجو برای: uv spectra
تعداد نتایج: 172424 فیلتر نتایج به سال:
Ultra-Violet (UV) radiation covers the spectrum of wavelengths from 100 to 400 nm. The potency and biological activity for a variety of endpoints differ by wavelength. For monitoring and communication purposes, different UV action spectra have been developed. These spectra use different weighting functions. The action spectrum for erythemal dose is the most widely used one. This erythemal dose ...
Dipicolinic acid (DPA) and the Ca2+ complex of DPA (CaDPA) are major chemical components of bacterial spores. With fluorescence being considered for the detection and identification of spores, it is important to understand the optical properties of the major components of the spores. We report in some detail on the room-temperature fluorescence excitation and emission spectra of DPA and its cal...
Nitrogenated, tetrahedral amorphous carbon (ta-C) ®lms prepared by the ®ltered cathodic vacuum arc (FCVA) technique have been studied using ultraviolet (UV, 244 nm) and visible (514 nm) micro-Raman scattering. The nitrogen ions were produced by a RF ion-beam source with a nitrogen ̄ow-rate varying from 0 to 10.0 sccm, which results in a nitrogen content from 0 to 10.8 at.% in the deposited ®lms...
Highly crystalline and pure lithium metasilicate (Li2SiO3) and lithium disilicate (Li2Si2O5) nanomaterials were synthesized by hydrothermal method and characterized by PXRD technique. The changes in the morphology and particle size of the synthesized nanomaterials with reaction time were investigated using SEM technique. The UV-Vis and photoluminescence spectra of the compounds were studied. Th...
While keto-amino cytosine is the dominant species in aqueous solution, spectroscopic studies in molecular beams and in noble gas matrices show that other cytosine tautomers prevail in apolar environments. Each of these offers two or three H-bonding sites (Watson-Crick, wobble, sugar-edge). The mass- and isomer-specific S1 ← S0 vibronic spectra of cytosine·2-pyridone (Cyt·2PY) and 1-methylcytosi...
in this paper, synthesis of the flower-like zinc oxide was performed using microwave assisted dicationic ionic liquid [mmp(im)2 ]br2 . the polycrystalline flower-like zinc oxide nanostructure was obtained when a suitable mole ratio (ionic liquid /zinc acetate) and short duration microwave was used. x-ray diffraction (xrd), scanning electron microscopy (sem), and photoluminescence (pl) spectra w...
The B̃-X̃ laser-induced-fluorescence spectrum of jet-cooled isopropoxy radical (i-C3H7O[middle dot]) has been recorded. Using an isolated state model the observed rotational and fine structure of the origin band has been well simulated to determine rotational constants for both the X̃ and B̃ states and the electron spin-rotation constants of the X̃ state. The line intensities are well simulated with...
We present a sample of spectroscopically confirmed QSOs with FUV-NUV color (as measured by GALEX photometry, FUV band: 1344-1786Å, NUV band: 1771 2831Å) bluer than canonical QSO templates and than the majority of known QSOs. We analyze their FUV to NIR colors, luminosities and optical spectra. The sample includes a group of 150 objects at low redshift (z < 0.5), and a group of 21 objects with r...
Tunable far-infrared-vacuum-ultraviolet two color ionization is used to obtain vibrational spectra of neutral silicon clusters in the gas phase. Upon excitation with tunable infrared light prior to irradiation with UV photons we observe strong enhancements in the mass spectrometric signal of specific cluster sizes. This allowed the recording of the infrared absorption spectra of Si(6), Si(7), a...
The conformation of benzo-18-crown-6-ether (B18C6) and its water encapsulation 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 conformers a...
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