Maxwell’s equations in the Majorana representation in a locally isotropic chiral medium

Maxwell’s equations in the Majorana representation are generalized to the case of a chiral medium. A relation between the dynamic variables and the parameters of a chiral medium is found. An expression for the current density 4-vector is obtained for the medium under consideration.     

Dynamics of fluorescence of solid solutions of quantum dots and the organic dye DODCI: Experiment and numerical simulation

The fluorescence of solid solutions of CdSe/ZnS quantum dots and the organic dye DODCI is investigated. It is shown that nonradiative transfer of electronic excitation energy to dye molecules, which with some probability lose their acceptor properties as a result of photoisomerization or photodegradation, is responsible for a significant increase in the fluorescence intensity of a donor. The degree of polarization of the donor fluorescence attains values exceeding 0.5, which is due to the difference in the fluorescence quantum yields of donors with different orientations of the oscillator with respect to the electric vector of an excitation light wave. A numerical simulation of the experimentally observed dependences is performed.     

Analysis of Radiation Phenomena in a Wedge Ended Dielectric Slab Waveguide

Radiation phenomena observed in a wedge shape ended dielectric slab waveguide are analyzed using mode matching technique. The case of transverse electric polarization (TE) being parallel to dielectric slab waveguide is assumed. In order to describe the fields in the wedge region, a stack of dielectric plates is assumed and in each layer the fields are expanded in terms of the mixed spectrum of guided and radiated modes. A similar expansion is used in the constant thickness slab waveguide while in free space medium a continuous-radiation mode expansion is used. Then a mode matching approach is applied, incorporating the orthogonality properties of mixed spectrum modes, in order to compute the wave fields inside the dielectric slab waveguide and wedge medium. Mode matching is achieved by discretizing the continuous radiation mode spectrum leading into a numerically stable solution provided a sufficient large number of points are used to convert integrals into finite summations. Numerical computations are carried out for various wedge geometries and shapes including linear and exponential profiles.     

Sorption of cesium from aqueous waste solution on a SuperLigÒ644 resin

Summary The removal of cesium from aqueous waste solution was investigated in a column setup using a relatively coarse SuperLig^ò644 resin. The bed volume (BV=140) at the onset of breakthrough surpassed the design requirement of 100 BV at 50% breakthrough, and also corresponds to 99.96% cesium removal. Cesium elution with 0.5M HNO₃was satisfactory with a peak BV of 2.5. The elution BV for C/C₀=0.01 was 10, which is less than the target of 15 BV. The percent of sorbed cesium eluted was 99.88%. Further, the BV of the various solutions used for the supporting process steps was sufficient.     

Effect of crystallochemical parameters of a piezophase on piezoelectric and pyroelectric properties of a polymer-piezoceramic composite

The piezoelectric and pyroelectric properties of the composites based on HDPE and lead-zirconate-titanate piezoceramics are shown to depend on the crystallochemical parameters of the piezophase. As the electroconductivity of cations and covalence of the B″″-O bonds decrease owing to enhanced adsorption interactions between polymer phases and the piezoceramic, the concentration of charge localization sites increases and the mobility of polymer chains at the interface decreases. As a result, piezoelectric and pyroelectric coefficients tend to increase.     

Some nucleophilic substitution reactions of s-triazolo[1,5-c]pyrimidines

Nucleophilic substitution of 5-methylthio- and 5-cyanomethylthio-7-amino-s-triazolo[1,5-c]pyrimidines has been carried out using sodium hydroxide, ammonia, hydrazine hydrate, and four amines. The cyanomethyl group is particularly reactive under these conditions and 5-cyanomethylthiotriazolopyrimidine can be used to functionalize this heterocycle.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 382–385, March, 1992.