Direct determination of uranium in sintered deeply depleted uranium oxide pellets by wavelength dispersive X-ray fluorescence spectrometry

This paper presents studies on direct non-destructive determination of uranium in sintered deeply depleted (DD) uranium oxide (UO₂) pellets by wavelength dispersive X-ray fluorescence (WDXRF) spectrometry. A special collet was designed and fabricated for holding the sintered DDUO₂ pellets for direct analysis, thus avoiding the sample preparation steps. The samples were analyzed using a calibration plot obtained from WDXRF spectra of matrix matched calibration standards. The WDXRF determined uranium values were found to be in very close agreement with titrimetric values and has reproducibility better than 0.05% (RSD, 1 s, n = 10) for the sintered DDUO₂ pellets having U: 86.81–88.04 wt%.

     

Efficient Synthesis of N‐Cyano α and β‐Amino Esters

A versatile method for the synthesis of N‐cyano α and β‐amino esters is described. Reaction of different amino esters with cyanogen bromide in dry ether gave the corresponding N‐cyano α and β‐amino esters in excellent yields.     

Effect of indium doping on photoelectrochemical properties of Cd0.9Zn0.1Se photosensitive films

Indium doped Cd_0.9Zn_0.1Se films have been synthesized by chemical bath deposition method. The deposited films act as photoanode in photoelectrochemical (PEC) cells. The varying concentration of indium from 0.01 to 1.0 mol% was used. The film thickness increases from 0.72 to 0.80 μm as doping concentration increases up to 0.1 mol%, thereafter it decreases. The cell configuration is n-Cd_0.9Zn_0.1Se:In|NaOH (1 M)+S (1 M)+Na₂S (1 M)|C_(graphite). The various performance parameters were examined with respect to doping concentration of indium. It is found that fill factor and efficiency is maximum for 0.1 mol% indium photosensitive films. This is due to low resistance, high flat band potential, maximum open circuit voltage as well as maximum short-circuit current. The barrier height was examined from the temperature dependence of the reverse saturation current. The lighted ideality factor was found to be minimum for 0.1 mol% indium photosensitive films. A cell utilizing doping photosensitive films showed a wider spectral response. The utility of this work is in improving efficiency of the PEC cell.     

Photoelectrochemical characterization of annealed cadmium selenide photoelectrode using sulphide–polysulphide electrolyte

Cadmium selenide films have been synthesized by dip method. Cadmium selenide acts as photoanode in photoelectrochemical (PEC) cells. The photoanode was annealed upto 473 K. The cell configuration is n-CdSe∣NaOH (1 M) +S (1 M) +Na₂S (1 M) ∣C_(graphite). Various performance parameters were examined with respect to annealed temperature. It is found that the fill factor and efficiency are maximum for photoelectrode annealed at 473 K. This is due to low resistance, high flat-band potential, maximum open-circuit voltage as well as maximum short-circuit current. The barrier height was examined from the temperature dependence of the reverse saturation current. The lighted ideality factor was found to be minimum for photoelectrode annealed at 473 K. A cell utilizing annealed photoelectrode showed a wider spectral response. The utility of this work is in improving the efficiency of PEC cells.     

Structure, surface morphological and opto-electronic properties of zinc sulphide thin films deposited by dip method

ZnS thin films have been deposited by dip technique using succinic acid as a complexing agent. The structural and morphological characterizations of films have been investigated by X-ray diffraction, scanning electron microscope. X-ray pattern shows crystalline has hexagonal structure. The films show that good optical properties high absorption and band gap value was found to be 3.7 eV. The specific conductivity of the film was found to be in order of 10⁻⁵ (Ω cm)⁻¹ and showing n-type conduction.     

Synthesis and antimalarial evaluation of cyclic beta-amino acid-containing dipeptides

This paper describes an efficient synthesis and the antiparasitic evaluation of cyclic beta-amino acid-containing dipeptides 3.1-3.6 and 4.1-4.5. The antimalarial properties of all these dipeptides have been evaluated in vitro against Plasmodium falciparum and in vivo against Plasmodium berghai. Compounds 4.4 and 4.5 have been found to be very effective in this respect, with IC50 values of 3.87 and 3.64 microg/mL in the in vitro test, while 4.5 has also been found to be active in the in vivo evaluation.