Structural, optical, and dielectric properties of A[(Mg0.32Co0.02) Nb0.66]O3 semiconductor, where (A = Ba, Sr or Ca)

Structural optical and dielectric properties of single phase A[(Mg0.32Co0.02) Nb0.66]O3, where A = Ba, Sr, or Ca, compounds were studied in the temperature range from room temperature (293 K) to 458 K. The X-ray diffraction revealed that the Ba[(Mg0.32Co0.02)Nb0.66]O3 [BMCN] compounds exhibit hexagonal symmetry whereas Sr[(Mg0.32Co0.02)Nb0.66]O3 [SMCN] and Ca[(Mg0.32Co0.02)Nb0.66]O3 [CMCN] compounds exhibit monoclinic symmetry. The replacement of Barium (r = 1.61 Å) by smaller ions like Strontium (r = 1.44 Å) or Calcium (r = 1.34 Å) in the polar dielectric Ba[(Mg0.32Co0.02) Nb0.66]O3 introduces the relaxation phenomenon and a gradual increase in the transition temperature maximum (Tm). The ac conductivity, as determined from the dielectric data, as a function of temperature and frequency, reveals the crossover from small polaron tunneling (SPT) to correlated barrier hopping (CBH) type conduction at » 370 K. The activation energy of the non-Debye type process evaluated both from the electric modulus and the conductivity data are nearly identical suggesting similarity in the hopping mechanism. The band gap of these materials lies in the range of narrow to wide band semi conductors. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2206

Enhanced visible fluorescence in highly transparent Al-doped ZnO film by surface plasmon coupling of Ag nanoparticles

ZnO:Al (AZO) film has been deposited on quartz substrate by Pulsed laser deposition and showed monophasic hexagonal structure of c-axis oriented nanorods upto 80 nm in height. AZO film was optimally conjugated with Ag nanoparticles (Ag NPs) in a hybrid nanostructure to achieve significant enhancement in the visible fluorescence emission. Augmented near field and extinction spectra of shape tailored Ag NPs and their dimers are simulated through FDTD method, and a direct association with fluorescence enhancement is established. Such plasmon-enhanced visible emission from a transparent conducting oxide could be very important for solar cell applications

Effect of storage temperature and duration on sugar content and sensory acceptability of strawberry pulp

Experiment was conducted to study the effect of different treatments on preservation of strawberry pulp at ambient and low storage temperature condition. The samples were pasteurized at 100°C for 15 minutes (T1), sodium benzoate 250 ppm (T2) and sodium benzoate 500 ppm (T3). The respective samples were stored for two months at room (25±5°C) and low (7±2°C) temperature conditions and reducing sugars; total sugar and sensory evaluation were recorded at three days of interval period. The results showed that the total sugar (%) increased in pulp sample maximum in T6 (5.9%) and minimum in T1 (4.8%), the maximum value regarding reducing sugars was recorded in T6 (4.9%) and minimum in T1 (1.4%) after 60th days of storage. However, reducing sugars and total sugar decreased in the stored pulp at room temperature and spoiled completely on 18th day of storage. The acceptability of organoleptic score decrease with the duration of storage in both ambient and low temperature. Among different treatments, sodium benzoate @ 500 ppm was found most effective and maintained the qualitative characteristics of preserved pulp at low (7±2°C) temperature condition. In future, these experimental results may prove very useful for storage of strawberry pulp for longer duration in better quality