Josephson junctions with negative second harmonic in the current-phase relation: properties of novel varphi-junctions

Several recent experiments revealed a change of the sign of the first harmonic in the current-phase relation of Josephson junctions (JJ) based on novel superconductors, e.g., d-wave based or JJ with ferromagnetic barrier. In this situation the role of the second harmonic becomes dominant and it determines the scenario of a 0-pi transition. We discuss different mechanisms of the second harmonic generation and its sign. If the second harmonic is negative the 0-pi transition becomes continuous and the realization of the so-called varphi junction is possible. We study the unusual properties of such a novel JJ and analyze the possible experimental techniques for their observation.Comment: submitted to PR

Dephasing time of disordered two-dimensional electron gas in modulated magnetic fields

The dephasing time of disordered two-dimensional electron gas in a modulated magnetic field is studied. It is shown that in the weak inhomogeneity limit, the dephasing rate is proportional to the field amplitude, while in strong inhomogeneity limit the dependence is quadratic. It is demonstrated that the origin of the dependence of dephasing time on field amplitude lies in the nature of corresponding single-particle motion. A semiclassical Monte Carlo algorithm is developed to study the dephasing time, which is of qualitative nature but efficient in uncovering the dependence of dephasing time on field amplitude for arbitrarily complicated magnetic-field modulation. Computer simulations support analytical results. The crossover from linear to quadratic dependence is then generalized to the situation with magnetic field modulated periodically in one direction with zero mean, and it is argued that this crossover can be expected for a large class of modulated magnetic fields.Comment: 8 pages, 2 figure

Effect of gelling agents on in vitro development of Amelanchier canadensis ‘Rainbow Pillar’

In vitro shoot multiplication responses of Amelanchier canadensis ‘Rainbow Pillar’ were studied on media solidifi ed with different gelling agents. The media were gelled either with 6.8 g l-1 fi brous agar-agar, or 50.0 g l-1 wheat starch, or 20.0 g l-1 Guar gum, or 15 g l-1 Isubgol or 50.0 g l-1 wheat starch mixed with 0.5 g l-1 Phytagel. Shoot cultures were grown for two months, thereafter the multiplication rates (number of newly developed shoots per explant) were counted and the length of shoots were measured. We found that the highest shoot multiplication of Amelanchier canadensis ‘Rainbow Pillar’ occurred on media gelled with Guar gum, while the longest shoots developed on media with Starch. About four-fold shoot number were obtained on media with Guar gum compared to the weakest results found on media gelled with Isubgol. Finally, considering all factors (shoot growth parameters, costs) the most economical gelling agent for Amelanchier canadensis ‘Rainbow Pillar’ was proved to be wheat starch among the tested alternatives which allows a 75.6% cost reduction

Effect of gelling agents on in vitro development of Amelanchier canadensis ‘Rainbow Pillar’

In vitro shoot multiplication responses of Amelanchier canadensis ‘Rainbow Pillar’ were studied on media solidifi ed with differentgelling agents. The media were gelled either with 6.8 g l-1 fi brous agar-agar, or 50.0 g l-1 wheat starch, or 20.0 g l-1 Guar gum, or 15 g l-1 Isubgolor 50.0 g l-1 wheat starch mixed with 0.5 g l-1 Phytagel. Shoot cultures were grown for two months, thereafter the multiplication rates (numberof newly developed shoots per explant) were counted and the length of shoots were measured. We found that the highest shoot multiplicationof Amelanchier canadensis ‘Rainbow Pillar’ occurred on media gelled with Guar gum, while the longest shoots developed on media withStarch. About four-fold shoot number were obtained on media with Guar gum compared to the weakest results found on media gelled withIsubgol. Finally, considering all factors (shoot growth parameters, costs) the most economical gelling agent for Amelanchier canadensis‘Rainbow Pillar’ was proved to be wheat starch among the tested alternatives which allows a 75.6% cost reduction

Noise Characteristics of Microwire Magnetometer

Current trends in modernization and miniaturization of ferroprobe sensors lead to replacement of amorphous ribbon cores with magnetic microwires. The miniaturization often causes degradation in the parameters of sensors, so, considering measurement of weak magnetic fields, it is necessary to explore noise parameters, temperature drift and stability of the magnetometer output value. The article deals with analysis of microwire sensor noise characteristics based on the experimental data processing. Using one second periodograms, the linear spectral density was processed. Obtained data are compared with corresponding parameters of a relax-type ferroprobe magnetometer

The Level of Arsenic in Water from Mineral Water Spring Gajdovka in Košice and the Associated Health Risks

In the recreation area Anička in Košice, there is a mineral spring that inhabitants call Gajdovka. It has been used with several breaks since the 19th century. Mineral water from this spring is specific by the presence of arsenic the concentration of which often exceeds the permitted limit level. This study focused on the analysis of the mineral composition of the spring water. Chemical and microbiological analysis was made in the years 2013—2015. In 2014, the mineral water Gajdovka was regularly monitored throughout the year with respect to the concentrations of arsenic, iron and hydrogen sulphide levels and water levels in the nearby river. The following mean concentrations were determined: total arsenic 0.063 mg.dm−3; iron 0.275 mg.dm−3; hydrogen sulfide 4.608 mg.dm−3. The concentration of iron was below the limit, while the limit for As(III) was exceeded in 2014 for 7 months. The statistical analysis showed that the season affects significantly the level of H2S and Fe and the water levels in the nearby river

Organic Colouring Agents in the Pharmaceutical Industry

Food dyes are largely used in the process of manufacturing pharmaceutical products. The aim of such a procedure is not only to increase the attractiveness of products, but also to help patients distinguish between pharmaceuticals. Various dyes, especially organic colouring agents, may in some cases have a negative impact on the human body. They are incorporated into pharmaceutical products including tablets, hard gelatine capsules or soft gelatine capsules, lozenges, syrups, etc. This article provides an overview of the most widely used colouring agents in pharmaceuticals, their characteristics and the EU legislation which regulates their use

New Generation of Magnetic Relaxation Sensors Based on the Melt-Spun FeCoBCu Alloys

We report on the development of new generation of magnetic relaxation sensors based on soft magnetic melt-spun ribbons with the composition $Fe_{63}Co_{21}B_{15}Cu$. The as-quenched amorphous alloy was subjected to thermomagnetic heat treatment in order to obtain sensor cores with optimized magnetic properties. The relaxation characteristics obtained for these cores by employing upgraded sensor electronics were compared to those based on the model simulations using Matlab-Simulink environment. The operational field range of new developed sensor core reached 300 μT within the frequency band 0-500 Hz, i.e. it is markedly extended as compared to the currently used cores based on the commercial VAC 25X material while keeping the similar sensitivity