Universal Access in the Information Society - The number of Web sites is growing exponentially and so are the people who are accessing them on mobile devices including people with special... 相似文献
Nano-photonics is an emerging area of optical materials, which would take the optointegrated circuits towards progress. Photonic crystal (PC) based power splitters are useful constituents for the design of photonic integrated circuits (PICs). They are very important devices for connecting different building blocks on an integrated optical chip. In this paper, a two-dimensional PC Y-junction power splitter (21×15 μm) based on the resonance effect with circular air holes etched on a hexagonal lattice with a period a is proposed. The plane wave expansion (PWE) and finite difference time domain (FDTD) techniques are used for analyzing the structure. The simulation results show that the optimum resonance occurs when the radius of the defect hole is 0.3a, leading to the maximum and equal power distribution. 相似文献
Fractional Fourier transform (FRFT) is a linear transform generalizing Fourier transform (FT) that plays an important role in the field of signal processing and analysis. FRFT contains an adjustable parameter α, which it rotates the signal in the time frequency plane and represents the signal in an intermediate domain between time and frequency. FRFT provides a measure about the angular distribution of signal's energy in time frequency plane. FT is a special case of FRFT when angle α is equal to π/2. This paper presents mathematical model for obtaining FRFT of PC6 window function. The different parameters of this window function are also obtained with the help of simulation results. A comparison of window function parameters is presented using FT and FRFT. Also comparison of this window function with Hanning window function is presented in terms of Side Lobe Fall off Rate (SLFOR). For different values of FRFT order, PC6 window function shows variation in different parameters. Thus by changing the FRFT order, the minimum stop band attenuation of the resulting window function can be controlled. 相似文献
Calcium silicates are very stable and good hosts for luminescent materials. These calcium silicates are synthesized using cost-effective agro-food wastes such as rice husk ash and eggshell powder along with doping of samarium oxide [Ca3?xSi2O7:xSm3+(x(%)?=?0.25, 0.50, 0.75, and 1.00)] via solid-state reaction method. X-ray diffraction confirms that the Ca3Si2O7 phase co-exists with the monoclinic-Ca2SiO4 phase. An increase in doping concentration of Sm3+ enhances the Ca2SiO4 phase content. Two types of morphology can be seen in the SEM micrographs confirming the presence of two phases. Photoluminescence emission spectra contain peaks in the visible region. Characteristic emission peaks of Sm3+ are present along with strong peaks due to the titanium ions present in agro-food wastes. Commission International de'Eclairage (CIE) co-ordinates correspond to the green region, which is significantly different from the CIE co-ordinates of Sm3+ doped samples derived from mineral oxides. This study presents an alternate use of agro-food wastes for synthesizing visible light-emitting phosphors and presents a mechanism for stabilizing Ca2SiO4 in waste-derived samples.
In the present study, hydroxyapatite (HAP) coating along with HAP/TiO2 coating has been deposited by high-velocity flame spray (HVFS) technique onto 316LSS. Titania was used as a bond coat and HAP as top coat in HAP/TiO2 coating. The main aim of the study is to investigate the corrosion behavior of thermal spray coating of HAP and HAP/TiO2 on steel. Electrochemical corrosion testing was carried out using potentiodynamic polarization test. The corrosion behavior of bare and as-sprayed specimens was analyzed in simulated body fluid known as Hank’s solution. As-sprayed specimens along with corroded specimens were further characterized by XRD, SEM/EDS, and x-ray mapping analysis. It was observed that the HAP/TiO2 coating possessed higher microhardness (280 Hv) as compared to HAP coating (254 Hv). Surface roughness also got enhanced in case of HAP/TiO2 coating (9.35 μm) as compared to pure HAP coating (7.37 μm). The porosity of the HAP coating was found to be higher than the bond coating. It was observed that the Ca/P ratio almost resembled that of the natural bone composition. The corrosion resistance of steel increased after the deposition of HAP and HAP/TiO2 coatings. The maximum corrosion resistance was exhibited by HAP/TiO2 coating. 相似文献
Limited research exists on how different oil types and time of addition affect starch digestibility of rice. This study aimed to assess the starch digestibility of white and red rice prepared with 2 oil types: vegetable oil (unsaturated fat) and ghee (clarified butter, saturated fat) added at 3 different time points during the cooking process (“before”: frying raw rice in oil before boiling, “during”: adding oil during boiling, and “after”: stir‐frying cooked rice in oil). Red rice produced a slower digestion rate than white rice. White rice digestibility was not affected by oil type, but was affected by addition time of oil. Adding oil “after” (stir‐frying) to white or red rice resulted in higher slowly digestible starch. Red rice cooked using ghee showed the lowest amount of glucose release during in vitro digestion. The addition of ghee “during” (that is boiling with ghee) or “before” (that is frying rice raw with ghee then boiling) cooking showed potential for attenuating the postprandial glycemic response and increasing resistant starch content. This is the first report to show healthier ways of preparing rice. White rice with oil added “after” (stir‐fried) may provide a source of sustained glucose and stabilize blood glucose levels. Boiling red rice with ghee or cooking red rice with ghee pilaf‐style may provide beneficial effects on postprandial blood glucose and insulin concentrations, and improve colonic health. The encouraging results of the present study justify extending it to an in vivo investigation to conclusively determine the effect of time of addition of fat when rice is cooked on blood glucose homeostasis. 相似文献
The present study was carried out to assess levels of different heavy metals like iron, manganese, copper and zinc, in vegetables irrigated with water from different sources. The results indicated a substantial build-up of heavy metals in vegetables irrigated with wastewater. The range of various metals in wastewater-irrigated plants was 116–378, 12–69, 5.2–16.8 and 22–46 mg/kg for iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), respectively. The highest mean levels of Fe and Mn were detected in mint and spinach, whereas the levels of Cu and Zn were highest in carrot. The present study highlights that both adults and children consuming vegetables grown in wastewater-irrigated soils ingest significant amount of these metals. However, the values of these metals were below the recommended maximum tolerable levels proposed by the [Joint FAO/WHO Expert Committee on Food Additives (1999). Summary and conclusions. In 53rd Meeting, Rome, June 1–10, 1999]. However, the regular monitoring of levels of these metals from effluents and sewage, in vegetables and in other food materials is essential to prevent excessive build-up of these metals in the food chain. 相似文献