Reversal of Nonlocal Vortex Motion in the Regime of Strong Nonequilibrium

We investigate nonlocal vortex motion in weakly pinning a-NbGe nanostructures, which is driven by a transport current I and remotely detected as a nonlocal voltage Vnl. At high I, the measured Vnl exhibits dramatic sign reversals that at low and high temperatures T occur for opposite polarities of I. The sign of Vnl becomes independent of that of the drive current at large abs(I). These unusual effects can be nearly quantitatively explained by a novel enhancement of magnetization, arising from a nonequilibrium distribution of quasiparticles at high T, and a Nernst-like effect resulting from local electron heating at low T

Nonlocal vs local vortex dynamics in the transversal flux transformer effect

In this follow-up to our recent Letter [F. Otto et al., Phys. Rev. Lett. 104, 027005 (2010)], we present a more detailed account of the superconducting transversal flux transformer effect (TFTE) in amorphous (a-)NbGe nanostructures in the regime of strong nonequilibrium in local vortex motion. Emphasis is put on the relation between the TFTE and local vortex dynamics, as the former turns out to be a reliable tool for determining the microscopic mechanisms behind the latter. By this method, a progression from electron heating at low temperatures T to the Larkin-Ovchinnikov effect close to the transition temperature Tc is traced over a range 0.26 < T/Tc < 0.95. This is represented by a number of relevant parameters such as the vortex transport entropy related to the Nernst-like effect at low T, and a nonequilibrium magnetization enhancement close to Tc. At intermediate T, the Larkin-Ovchinnikov effect is at high currents modified by electron heating, which is clearly observed only in the TFTE

Nonlocal vortex motion in mesoscopic amorphous Nb0.7Ge0.3 structures

We study nonlocal vortex transport in mesoscopic amorphous Nb0.7Ge0.3 samples. A dc current I is passed through a wire connected via a perpendicular channel, of a length L= 2-5 um, with a pair of voltage probes where a nonlocal response Vnl ~ I is measured. The maximum of Rnl=Vnl/I for a given temperature occurs at an L-independent magnetic field and is proportional to 1/L. The results are interpreted in terms of the dissipative vortex motion along the channel driven by a remote current, and can be understood in terms of a simple model.Comment: 4 pages, 3 figure

Estimation of Standards for Gold and Silver Sampling

U protetskoj se terapiji upotrebljava vrlo mnogo plemenitih slitina različita sastava. Plemeniti metali su sinonim za biokompatibilnost. Zlato je jedna od najinertnijih plementih kovina, a srebro jedna od najreaktivnijih. Cilj rada bio je razvijanje i raščlamba kromatografskih mrlja čistoga zlata i srebra (Aurodent, Celje, Slovenija). Kovine su uzorkovane na sobnoj temperaturi otopinom voda-HCl(conc.) (v/v 10:1) tijekom 10 s pri stalnom naponu struje od 4,5 V. Otopine kationa iz čistih kovina i 10 µl standardnih otopina soli nanesene su na HPTLC kromatografske ploče (Merck, Darmstadt, Njemačka) 10 x 10 cm presvučene celulozom. Ploče su razvijene u staklenoj kromatografskoj komori zasićenoj mobilnom fazom izo-amilni alkohol: HCl(conc.) : acetonitril u omjeru 5,4 : 4,3 : 0,3 do visine od približno 8 cm. Kada su razvijene sušene su u struji vrućega zraka, a kationi su vizualizirani prskanjem zasićenim etanolnim otopinama difenilkarbazida, alizarina, kvercetina te 0,1% otopinom ditizona u kloroformu. Nakon prskanja i sušenja ploče su izložene parama amonijaka i učinjena je vizualizacija. Uzorkovano zlato i srebro međusobno se razlikuje bojom kromatografskih mrlja i utvrđenim Rf vrijednostima. Metodom anodnoga uzorkovanja slitina i identifikacijom kationa tankoslojnom kromatogafijom moguće je dokazati postojanje određenih kationa s udjelom mase većim od 1%, ne oštećujući pritom sam uzorak. Metoda se pokazala prikladnom za uzorkovanje kovina zlata i srebra, što je nastavak dosadašnih istraživanja u identifikaciji određenih sastavnica u pojedinim slitinama ili u inkorporiranome protetskom radu.Different precious dental alloys are used in prosthodontic therapy. Precious metals are the synonym for biocompatibility. Gold is one of the most inert and silver the most active presious metals. The purpose of this study was to develop an analyze the chromatographic spots of pure gold and silver (Aurodent, Celje, Slovenia). The sampling was performed in a water-HCl(conc.) solution in a 10 : 1 volume ratio at room temperature using a 4,5 V battery. Dissoluted cations and solutions of standard elements (salts of gold and silver) were applied to HPTLC plates (Mareck, Darmstadt, Germany) 10 x 10 cm precoated with cellulose. Plates were developed in a vertical separating chamber to a height of approximately 8 cm saturated with iso-amyl (3.methyl-1-butanol) - HCl (36,5%) - acetonitrile in a volume ratio 5,4 : 4,3 : 0,3. After development, plates were dried in (a steam of) hot air and the cations were visualized by spraying with the saturated ethanolic solutions of alizarin, diphenylcarbazide, quercetin and 0,1% chlorophorm solution of dithizone. After drying, plates were exposed to NH3 vapor. According to the Rf value and the color of the spots, the difference between gold and silver were obtained. Anodic sampling with thin-layer chromatography is a suitable, nondestructive method for identification of cations presents in different dental alloys. It is possible to identify the cations with their mass ratio W > 1%. The results have shown that the described method is suitable for analysis of gold and silver and it can be used in future work to identify those cations in dental alloys of unknown composition

The Amplitude of Non-Equilibrium Quantum Interference in Metallic Mesoscopic Systems

We study the influence of a DC bias voltage V on quantum interference corrections to the measured differential conductance in metallic mesoscopic wires and rings. The amplitude of both universal conductance fluctuations (UCF) and Aharonov-Bohm effect (ABE) is enhanced several times for voltages larger than the Thouless energy. The enhancement persists even in the presence of inelastic electron-electron scattering up to V ~ 1 mV. For larger voltages electron-phonon collisions lead to the amplitude decaying as a power law for the UCF and exponentially for the ABE. We obtain good agreement of the experimental data with a model which takes into account the decrease of the electron phase-coherence length due to electron-electron and electron-phonon scattering.Comment: New title, refined analysis. 7 pages, 3 figures, to be published in Europhysics Letter

Effect of galactomannan hydrocolloids on gelatinization and retrogradation of tapioca and corn starch

The aim of the present study was to investigate the effect of galactomannan hydrocolloids (guar gum and locust bean gum) on gelatinization and retrogradation of tapioca and corn starch. Differential scanning calorimetry (DSC) was used to characterize the behaviour of tapioca and corn starch with and without additives. Results showed that guar gum and locust bean gum retarded the retrogradation of tapioca and corn starch at both investigated temperatures (4 and 25 °C). Guar gum retarded retrogradation of tapioca starch more than locust bean gum, on the other hand, locust bean gum had a greater effect on reduction of the recrystallization of corn starch. Temperatures of gelatinization did not vary significantly in starch-hydrocolloid systems. Additions of galactomannan hydrocolloids caused a decrease in gelatinization enthalpy of both starches

Building New University Hospital – What Citizens Know and Policy Makers Should be Aware of

Survey of citizens’ attitudes in the process of strategic decision making is one of the most important methods for determining health care priorities. We describe the results of a survey carried out in December 2001, with an aim to collect and analyze the attitudes of the citizens and health care professionals toward the possibilities and strategies of construction of the University Hospital in Blato, Zagreb. The first referendum on the construction of the new hospital was conducted among Zagreb citizens in 1982, when they agreed that the new University Hospital was much needed. Zagreb citizens confirmed once again their attitudes toward and opinions on the need to continue the construction of new hospital in the city outskirts. By 1992, when the construction of the hospital was halted due to insufficient financial means, Zagreb citizens had already invested over 150 million in the project. It is interesting that today, 89.4% of the citizens and 74.5% of physicians agree that the new hospital building should be completed. Also, 66.7% of the citizens and 88% of physicians think that this hospital should be a University hospital that could offer the most complex treatments and medical education. To finish the construction of the new hospital further 200 million needs to be invested. Survey showed that 71% of citizens and 82.2% of physicians think that funds should be raised from some form of credit or budget rather than by special local tax, additional tax or voluntary tax. This project will significantly determine the future of hospital and health care system in Croatia due to its capacities in terms of space, technology, and staff. Before the decision to continue with the new hospital construction be made, the expected future needs, demands, and supply of the health care services in hospital sector in Zagreb and Croatia should be provided using SWOT analysis for each of existing the facilities