Results 1 - 10 of 191
Results 1 - 10 of 191. Search took: 0.019 seconds
|Sort by: date | relevance|
[en] A laboratory electrospark system permits the creation of an overvoltage in the gap between dispersible electrodes. Conductive nanopowder may be produced by an electrospark method with a considerable overvoltage in the electrode gap. The production of small powder batches for additive technology by this means is promising and economical.
[en] As wastage of a large percentage of source material used is the main disadvantage of successive ionic layer adsorption and reaction (SILAR) technique, in the present work, a new approach is adopted by simultaneously preparing thin films and powders from the SILAR bath solutions. The amount of source material used for thin film and powder form is estimated to find the resultant wastage. In this study, ZnS thin film and ZnS powder were prepared from the same SILAR bath. The characteristics of both the product were analyzed using X-ray diffraction, optical, energy dispersive X-ray analysis studies and the photocatalytic abilities of the prepared samples were determined and compared.
[en] We have synthesized gelatin-functionalized hydroxyapatite nanoparticles (Gel-HANPs) by a simple wet chemical method with an aim to evaluate them for targeted cancer therapy. The successful formation of Gel-HANPs is evident from PXRD and FTIR analysis. The average hydrodynamic diameter of nanoparticles was found to be ∼ 200 nm with a negative charge of ∼ 13 mV. The folate molecules were conjugated to the surface of Gel-HANPs by chemical cross-linking (FA-Gel-HANPs). The conjugation of folate molecules to Gel-HANPs was ascertained by UV-visible spectroscopy. The drug loading capacity of FA-Gel-HANPs was investigated using a positively charged anticancer drug, doxorubicin hydrochloride (DOX). The loading capacity of DOX was found to be ∼ 65%. The conjugation of DOX to Gel-HANPs has been assigned to the electrostatic binding of positively charged drug to the negatively charged nanoparticles. The DOX loaded FA-Ge1-HANPs shows time and pH-responsive release of DOX under reservoir-sink condition. (author)
[en] Tin oxide (SnO2) nanostructures were synthesized by simple chemical precipitation route and SnO2 photoelectrode films were fabricated on fluorine doped SnO2 substrate. Using Rose Bengal dye as a sensitizer, scanning electron microscopic analysis was performed for the unsensitized and sensitized SnO2 photoelectrodes to study the changes in surface morphology. Optical absorption studies for Rose Bengal dye in solution and the photoelectrodes sensitized with it were conducted using UV-vis spectrophotometer. Effects of dye loading time on photovoltaic characteristics of the cell fabricated using the sensitized photoelectrode were studied. The highest performance of device was obtained for the photoelectrode with 24 h dye loading time which showed the VOC , JSC and FF of about 385 mV, 0.874 mA/cm2 and 78 %, respectively. (author)
[en] Contrast Agents (CAs) defined as a substance that enhances the contrast of internal body structures or fluids during magnetic resonance imaging (MRI). Due to the major limitation of the commonly employed (mostly Gd-based chelates) clinical MRI CAs, that is suitable only at lower magnetic field strengths (∼1.5 T). The inefficiency of these CAs at high field (> 9.4 T), demands the paramagnetic lanthanides based NPs for high field MRI applications. Usually, chelates have short circulation time due to fast renal excretion limiting further their usefulness in small-animal studies. Generally, the short circulation time has been overcome by combining the Gd ion with bigger proteins and polymer molecules, but the tumbling times, of such complexes are still too fast (10 s) for optimal performance at higher magnetic fields. In contrast, selected NPs with longer tumbling times can overcome the shortcomings of these Gd - based complexes. The NPs have a high density of metal ions per unit of CA enabling MR signal shortening at lower concentrations compared to chelate that usually are used at micro-molar concentrations. (author)
[en] In this experimental study, graphene oxide (GO) nanopowder was prepared and irradiated by the 60 Co γ-rays in different absorbed doses of 0, 10, 30, 50, 80, 100, 120 and 150 kGy at dose rate of 1.62 Gy s - 1 at room temperature. Field emission scanning electron microscope and high-resolution transmission electron microscopy analyses were used to investigate structural defects in GO material. Then, using Raman spectroscopy, the ratio of I D / I G related to D- and G-bands in the wavenumbers of 1350 and 1586 cm - 1 was, respectively, measured in terms of absorbed dose to determine the dose–response of GO material. The results showed that the dose–response of c -irradiated samples at the dose range of 0–50 kGy was linear. There was a decline in dose–response after 100 kGy due to graphitization of carbon nanostructure material or annealing the defects in the sample. The results of this study showed that the linearity response of c -irradiated GO as a novel passive dosimeter is suitable for the dosimetry of γ-rays at the radiation processing level. (author)
[en] Lead-free piezoceramics are gaining importance for replacing widely used toxic lead-based PZT family. Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) is one such potential candidate that has attracted attention in recent years. Despite its high piezoelectric properties, BCZT suffers from a major drawback of low Curie temperature (Tc) that restricts its practical applicability. Numerous methods have been attempted to further improve its properties so as to make it a truly lead-free choice. In the present work, a systematic study is performed on BCZT ceramics synthesized from nanopowders produced by high-energy ball milling. It is found that there exists an optimum particle size of the starting powders at which piezoelectric charge coefficient (d33) of the corresponding ceramic is enhanced by 110% with a simultaneous increase in Tc by 7 °C. The study reveals that economically viable high-energy ball milling technique can be used to strengthen the candidature of BCZT ceramic system for replacing lead-based piezoceramics.
[en] A new method for liquefying coal using dielectric barrier discharge plasma has been studied. By utilizing waste oil as the solvent and processing coal nanopowder in the plasma for 10 min, we have attained a liquid yield of more than 80%. The experiment shows that not only the coal nanopowder promoted the liquefaction process, but hydrogen radicals improved the liquid yield effectively. In the plasma processing, the phenomenon of the changing color of the nanopowder solution and not producing a solid residue has been obviously observed. The rational parameters that affected the liquefaction of coal nanopowder have been achieved through the experiment, and the liquefied products have been analyzed. (paper)