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11.
The results of electrical conductivity measurements in heavily doped RbCl:CoCl2 crystals with 2500 and 6000 ppm of cobalt are being reported in this paper. The different regions of the conductivity plots
for the crystals with the two concentrations of cobalt have been explained and relevant energy parameters determined. The
crystals with 6000 ppm of cobalt have been found to contain two types of precipitates one of these being of the same type
as that existing in RbCl crystals with 2500 ppm of cobalt while the other being of a different composition.
Further, it has been found that the crystals appear blackened after heating during measurements. The blackening has been attributed
to the expulsion of cobalt from the bulk of the crystal which forms an oxide at the surface. 相似文献
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J.C. Joshi N.C. Pandey B.C. Joshi B.C. Pandey J. Joshi 《Solid State Communications》1978,27(11):1051-1053
Characteristic visible green emission of Ho3+ and Er3+ was observed in zinc tellurite glass. Multiphonon relaxation theory was quantitatively applied to explain the experimentally obtained results. Fluorescence assignments and lifetime measurements have also been made. 相似文献
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The etching conditions of an indigenously prepared thin film of pentaerythritol tetrakis(allyl carbonate) (PETAC) were standardised for the use as a nuclear track detector. The optimum etching times in 6?N NaOH at 70°C for the appearance of fission and alpha tracks recorded in this detector from a 252Cf solid source were found to be 30 min and 1.50?h, respectively. The experimentally determined values for the bulk and track-etch rates for this detector in 6?N NaOH at 70°C were found to be 1.7?±?0.1 and 88.4?±?10.7?µm/h, respectively. From these results, the important track etching properties such as the critical angle of etching, the sensitivity and the fission track registration efficiency were calculated and compared with the commercially available detectors. The activation energy value for bulk etching calculated by applying Arrhenius equation to the bulk etch rates of the detector determined at different etching temperatures was found to be 0.86?±?0.02?eV. This compares very well with the value of about 1.0?eV reported for most commonly used track detectors. The effects of gamma irradiation on this new detector in the dose range of 200–1000?kGy have also been studied using bulk etch rate technique. The activation energy values for bulk etching calculated from bulk etch rates measurements at different temperatures were found to decrease with the increase in gamma dose indicating scission of the detector due to gamma irradiation. The optical band gap of this detector was also determined using UV–visible spectrometry and the value was found to be 4.37?±?0.05?eV. 相似文献
18.
Vanadium redox flow battery (VRFB) is a promising technology for large-scale renewable energy storage. Design of ion-exchange membrane (IEM) with desired properties like low-cost, mechanically chemically stable, low vanadium ion permeability and high proton conductivity is one of the major challenges. Here, we report the design and synthesis of novel poly(tetrafluoroethylene)-zirconium phosphate (PTFE-ZrP) asymmetric IEM using a simple brush coating method. XRD results confirmed the presence of α-ZrP crystalline phase onto the top layer of the membrane. Excellent mechanical strength was observed with burst pressure of 3.22 × 105 N m?2. Oxidative stability of membrane in Fenton’s reagent was much better than Nafion-115. Vanadium ion (V4+) permeability of the membrane was more than three times lower than that of Nafion-115. Single-cell VRFB with PTFE-ZrP membrane showed ~80% energy efficiency below 30 mA cm?2. Very high columbic efficiency ~100% of VRFB with PTFE-ZrP membrane confirmed little contamination of electrolyte due to cross-mixing. 相似文献
19.
Rescaled mean spherical approximation (RMSA) has been used to calculate the structure factor for the aqueous suspension of
polystyrene macroions with the interaction potential taken according to Derjaguin and Landau (1941) and Verwey and Overbeek
(1948) (DLVO) model. The effects of charge over the macroion and size on the surface potential and therefore, the structure
factor have been studied. The breakdown of the DLVO potential with an excess charge over the macroion (⩾800e) has been reported.
The oscillation in the first peak height of structure factor versus wave vector curve with size has been correlated with the
Debye length. 相似文献
20.
In the present paper, photovoltaic studies of dye-sensitized solar cells (DSSCs) based on betacyanin/TiO2 and betacyanin/WO3–TiO2 have been done. The cell performances were compared through I–V curves and wavelength dependant photocurrent measurements for the two new types of DSSCs. The TiO2-coated DSSC showed the photovoltage and photocurrent of 300 mV and 4.96 mA/cm2, whereas the cell employing WO3–TiO2 photoelectrode showed the values 435 mV and 9.86 mA/cm2, respectively. The conversion efficiency of TiO2 based dye-sensitized solar cell was found to be 0.69 %, while WO3–TiO2-based cell exhibited a higher conversion efficiency of 2.2 %. The better performance of the WO3–TiO2 dye-sensitized solar cell photoelectrode is thought to be due to an inherent energy barrier at the electrode/electrolyte interface leading to the reduced recombination of photoinduced electrons. 相似文献