Quadrupole Interaction Contribution to the Hyperfine Structure of P-States in Muonic Lithium,Beryllium, and Boron Ions

The contribution of the quadrupole interaction to the hyperfine structure of the spectrum of the energy of muonic lithium, beryllium, and boron ions is calculated within the quasipotential method in quantum electrodynamics. The numerical results obtained improve previous calculations due to the consideration of new corrections. They can be used for comparison with future experimental data.     

The surface limit of Brownian motion in tubular neighborhoods of an embedded Riemannian manifold

We construct the surface measure on the space C([0,1],M) of paths in a compact Riemannian manifold M without boundary embedded into which is induced by the usual flat Wiener measure on conditioned to the event that the Brownian particle does not leave the tubular ε-neighborhood of M up to time 1. We prove that the limit as ε→0 exists, the limit measure is equivalent to the Wiener measure on C([0,1],M), and we compute the corresponding density explicitly in terms of scalar and mean curvature.     

Thermal degradation of natural and treated hemp hurds under air and nitrogen atmosphere

Sustainability goals are essential driving principles for the development of innovative materials in the construction industry. Natural fibers represent an attractive alternative as reinforcing material due to good mechanical properties and sustainability prerequisites. The study has been focused on the comparative investigation of chemical and physical treatments of hemp hurds and their influence on the thermal behavior of main hemp constituents in air and nitrogen atmosphere. Thermal decomposition of hemp hurds involves several parallel reactions related to heat and mass transfer processes. A comparison of DSC and TG/DTG results of hemp hurds samples before and after treatments demonstrates a better thermal stability for treated samples. It is caused by changes in chemical composition due to a partial removal of non-cellulosic components from hemp hurds structure, an increase in cellulose content and decrease in its degree of polymerization. The results show different thermal behavior of the hurds samples heated under nitrogen and air atmosphere. Based on DTG records, several-stage process of mass loss has been found for the samples under air, whereas only two-stage process under nitrogen.

     

Lost branches in the spectrum of Parekh waves

It has been shown that a traditional approach to the calculation of a Parekh wave (a shear surface acoustic wave propagating along the mechanically free surface of a ferromagnet laterally magnetized by a static external magnetic field) including magnetoelastic interaction and neglecting magnetostriction inadequately describes the spectrum of the wave in the high-frequency range.     

Pyridinyl hydrazone derivatives of thiacalix[4]arene as selective extractants of transition metal ions

The recognition ability of pyridinyl hydrazone derivatives of cone- and 1,3-alternate tetrathiacalix[4]arenes towards transition and alkali metals has been investigated by picrate extraction method. The stoichiometry of complexes and the extraction constants have been determined. It has been found that hydrazones do not extract alkali metal ions but show an excellent affinity towards transition and heavy metal cations. The removal of tert-butyl groups from calix[4]arene platform in the case of cone and 1,3-alternate isomers leads to an increase of d-ion extraction selectivity or efficiency.     

Evanescent wave intensification in surface spin-wave acoustics and magnetic/nonmagnetic interface electrodynamics

A relation is found between the maximum intensification of an evanescent elastic shear wave excited in a magnetic field and the enhancement of the Schoch effect. The conditions necessary for the electromagnetic analog of this relation for the Goos-Hänchen effect in the case of a TM (TE) body wave beam incident from without are determined.     

Study of Streptavidin-Modified Quantum Dots by Capillary Electrophoresis

Great boom of nanotechnologies impacts almost all areas of science and therefore detail understanding of the properties of nanomaterials as well as their interaction abilities is required. Surface modification and functionalization of nanoparticles is of a great interest due to the wide range of applications in the area of nanomedicine, nanobiology, and/or biochemistry. In this study, CdTe QDs were synthesized using microwave reactor and their surface was modified by streptavidin to ensure further suitability for bioconjugation with biotin-labelled oligonucleotides. For characterization of the synthesized QDs and for monitoring of the interaction with the oligonucleotide, capillary and gel electrophoresis was used. Moreover, complementary advantages of absorption (CE–UV) and laser-induced fluorescence detection (CE–LIF) were exploited. Comparison the electrophoretic mobilities obtained for streptavidin-modified QDs by CE–LIF (?9.87 × 10^?9 m²/V/s) and by CE–UV (?10.02 × 10^?9 m²/V/s) was in a good agreement enabling us to identify the peak of streptavidin-modified QDs in the CE–UV electropherogram containing also the peak of unreacted streptavidin. Subsequent conjugation of streptavidin-modified QDs with two model biotinylated oligonucleotides (BCL-2 and HBV) led to formation of the complex represented in the electropherograms as a very sharp peak. This peak height increased with time for 15.5 and 27 mAU using BCL-2 oligonucleotide and HBV oligonucleotide, respectively during 30 min interaction.     

Mercury(II) and silver(I) receptors based on tetrathiacalix[4]arene hydrazones

The extraction ability of phenyl hydrazone derivatives of cone- and 1,3-alternate tetrathiacalix[4]arenes towards to some alkali, alkaline earth, transition and heavy metal ions has been investigated by picrate extraction method. The synthesized cone-tetrathiacalix[4]arene hydrazones show a high efficiency coupled with an excellent selectivity towards for Ag⁺ and Hg²⁺ ions. The stoichiometry of complexes and the extraction constants have been determined. The influence of calix[4]arene platform’s structure and the electron donor substituents in phenyl fragments on the extraction efficiency has been discussed.     

Two-dimensional diffraction on a cylinder induced by a laser beam in a nonlinear gradient medium

A wave theory was developed and a numerical simulation performed of the diffractive flow of a signal wave around a negative inhomogeneity induced by a cylindrical pump beam in nonlinear medium while keeping both waves in the potential well. It was shown that a broad pump beam reflects a narrow signal beam. A nonlinear waveguide (a dark soliton) is described as well. These phenomena can be observed in Bose-Einstein condensate (BEC) and in a gradient waveguide.