molecular sieves mcm-41 were synthesized from rice husk ash (rha) as alternative sources of silica. the material was synthesized by a room temperature method from a gel with the molar composition sio2: 1.6ea: 0.215hdtmabr: 325h2o with ph correction. the cetyltrimethylammonium bromide (ctmabr) was used as a structure template. nanocomposite containing 5.0 and 10.0 wt.% of cu was synthesized unde...

a useful nanophotocatalyst (la,s-tio2) was prepared by a sol-gel method and characterized by uv–vis diffuse reflectance spectroscopy (drs), x-ray diffraction (xrd), photoluminescence emission spectroscopy (pl) and scanning electron microscopy (fesem). the results showed that the la,s-tio2, which calcined at 550 °c, contained only anatase phaseand its crystal size was 23 nm. in addition, the fes...

Ni/Al-HMS/HZSM-5 catalysts with varying amounts of Si/Al ratios were prepared via the impregnation method and evaluated for the hydrogenation of benzene at 130−190 °C. To study the catalyst characterization, various methods were used as X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, temperature-programmed des...

In this study, cellulose nanocrystals (CNC) was prepared and meso-tetrakis(4-nitrophenyl)porphyrin (TNPP) was immobilized on it. The product was identified by techniques of UV-Vis, fourier transform infrared (FT-IR), diffuse reflectance UV-Vis spectroscopy (DRS), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The effect of an amount of a loaded porphyrin comp...

This paper describes a method for quantitative spot test analysis of hydrochlorothiazide using diffuse reflectance spectroscopy. The reflectance measurements were performed analyzing the colored compound (l = 585 nm) produced from the reaction between hydrochlorothiazide and pdimethylaminocinnamaldehyde (PDAC) in acid medium. This reaction occurred on filter paper after heating to 80oC for 8 mi...

Optical spectroscopy show great promise for diagnosing the earliest stages of cancer. Light scattering spectroscopy (LSS), the study of single elastic backscattering as a function of wavelength and angle, can detect subcellular structural changes in early cancer. We have developed two novel differential light scattering spectroscopy techniques, space differential LSS (SD/LSS) and p-angle differ...

We present computationally efficient and accurate semiempirical models of light transfer suitable for real-time diffuse reflectance spectroscopy. The models predict the diffuse reflectance of both (i) semi-infinite homogeneous and (ii) two-layer media exposed to normal and collimated light. The two-layer medium consisted of a plane-parallel slab of finite thickness over a semi-infinite layer wi...

The evolution of the electronic absorption edge of type I, II and III kerogen is studied by diffuse reflectance UV–Visible absorption spectroscopy. The functional form of the electronic absorption edge for all kerogens measured is in excellent agreement with the ‘‘Urbach tail’’ phenomenology. The Urbach decay width extracted from the exponential fit within the visible range is strongly correlat...

Model-based light scattering spectroscopy (LSS) seemed a promising technique for in-vivo diagnosis of dysplasia in multiple organs. In the studies, the residual spectrum, the difference between the observed and modeled diffuse reflectance spectra, was attributed to single elastic light scattering from epithelial nuclei, and diagnostic information due to nuclear changes was extracted from it. We...

Ti-SBA-15 mesoporous materials were directly synthesized via a hydrothermal process and characterized by using nitrogen adsorption-desorption measurements, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflectance ultraviolet-visible spectroscopy, and infrared ray spectroscopy. The effect of synthesis temperatures on the structure and catalytic effic...