Mapping the Wigner distribution function of the Morse oscillator into a semi-classical distribution function

The mapping of the Wigner distribution function (WDF) for a given bound-state onto a semiclassical distribution function (SDF) satisfying the Liouville equation introduced previously by us is applied to the ground state of the Morse oscillator. Here we give results showing that the SDF gets closer to the corresponding WDF as the number of levels of the Morse oscillator increases. We find that for a Morse oscillator with one level only, the agreement between the WDF and the mapped SDF is very poor but for a Morse oscillator of ten levels it becomes satisfactory.Comment: Revtex, 27 pages including 13 eps figure

String Picture of Bose-Einstein Condensation

A nonrelativistic Bose gas is represented as a grand-canonical ensemble of fluctuating closed spacetime strings of arbitrary shape and length. The loops are characterized by their string tension and the number of times they wind around the imaginary time axis. At the temperature where Bose-Einstein condensation sets in, the string tension, being determined by the chemical potential, vanishes, the system becomes critical, and the strings proliferate. A comparison with Feynman's description in terms of rings of cyclicly permuted bosons shows that the winding number of a loop corresponds to the number of particles contained in a ring.Comment: 13 pages, 6 figures; references adde

Collisional Semiclassical Aproximations in Phase-Space Representation

The Gaussian Wave-Packet phase-space representation is used to show that the expansion in powers of $\hbar$ of the quantum Liouville propagator leads, in the zeroth order term, to results close to those obtained in the statistical quasiclassical method of Lee and Scully in the Weyl-Wigner picture. It is also verified that propagating the Wigner distribution along the classical trajectories the amount of error is less than that coming from propagating the Gaussian distribution along classical trajectories.Comment: 20 pages, REVTEX, no figures, 3 tables include

The Inhibition of Ureteral Motility by Periureteral Adipose Tissue

Perivascular adipose tissue exerts an anticontractile influence on vascular smooth muscle. This study was conducted to determine whether periureteral adipose tissue (PUAT) could exert a similar influence upon ureteral smooth muscle. Acetylcholine-stimulated (10−7 M–10−4 M) contractile responses of ureteral segments obtained from male Wistar rats were recorded in the presence and absence of PUAT. Ureters with PUAT generated phasic contractile responses with significantly lower frequencies (P < 0.001) and magnitudes (P < 0.001) compared with ureters cleared of their periureteral adipose tissue. Removal of PUAT significantly increased the frequency (P < 0.01) and magnitude (P < 0.01) of the contractile responses. Bioassay experiments demonstrated that ureters with PUAT released a transferable factor that significantly reduced frequencies (P < 0.05), but not magnitudes, of the contractile responses of ureters cleared of PUAT. The nitric oxide synthase inhibitor L-NNA (10−4 M) did not significantly influence the anticontractile effect exerted by ureters with PUAT. This is the first study to demonstrate that ureteral motility is influenced by its surrounding adipose tissue. The PUAT has an anticontractile effect which is mediated by a transferable factor released from the PUAT. The identity of the factor is unknown but does not exert its effect through nitric oxide

Electrocatalysis of Lithium (Poly-) Sulfides in Organic Ether-Based Electrolytes

This work aims at identifying an effective electrocatalyst for polysulfide reactions to improve the electrode kinetics of the sulfur half-cell in liquid organic electrolytes for alkali-sulfur cells. To increase the charge and discharge rates and energy efficiency of the cell, functionalized electrocatalytic coatings have been prepared and their electrode kinetics have been measured. To the best of our knowledge, there is no extensive screening of electrocatalysts for the sulfur electrode in dimethoxyethane:1,3-dioxolane (DME:DOL) electrolytes. In order to identify a suitable electrocatalyst, apparent exchange current densities at various materials (Al, Co, Cr, Cu, Fe, Steel, glassy carbon, ITO, Ni, Pt, Ti, TiN, Zn) are evaluated in a polysulfide electrolyte using potentiodynamic measurements with a Butler-Volmer fit. The chemical stability and surface morphology changes after electrochemical measurements are assessed with X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The results show that cobalt is a promising candidate with appropriate electrocatalytic properties for polysulfide reactions while being stable in the electrochemical environment, followed by chromium in terms of catalytic activity and stability. Sputtered TiN was found to be a very stable material with very low catalytic activity, a possible current collector for the cell

Three-body Faddeev Calculation for 11Li with Separable Potentials

The halo nucleus $^{11}$Li is treated as a three-body system consisting of an inert core of $^{9}$Li plus two valence neutrons. The Faddeev equations are solved using separable potentials to describe the two-body interactions, corresponding in the n-$^{9}$Li subsystem to a p$_{1/2}$ resonance plus a virtual s-wave state. The experimental $^{11}$Li energy is taken as input and the $^{9}$Li transverse momentum distribution in $^{11}$Li is studied.Comment: 6 pages, RevTeX, 1 figur

Исследование реологических свойств растворов ксантановой смолы и крахмала для оценки межмолекулярного взаимодействия данных реагентов в биополимерных буровых растворах

Работа направленна на разработку систем биополимерных растворов для бурения горизонтальных участков скважин с повышенной эффективностью очистки ствола.The work is aimed to develope systems of biopolymer drilling fluids for horizontal drilling with increased efficiency of wellbore cleaning

Erratum Analysis of the physical and photoelectrochemical properties of c Si p a SiC H p photocathodes for solar water splitting

The photoelectrochemical (PEC) properties of sputtered aluminum doped hydrogenated amorphous silicon carbide thin films grown on p-type crystalline silicon substrates were investigated in 1 M H2SO4<i solution under chopped light illumination. Optical and structural properties of the top absorber layer were systematically assessed after post-deposition isochronical annealing treatments. Samples exhibited a noticeable improvement of the opto-electronic properties after thermal treatments. In addition, an abrupt enhancement of the photocurrent was observed reaching a saturation value of 17 mA cm(-2) at -1.75 V vs. Ag/AgCl (3.5 M KCl). In this research we propose that this enhancement effect is associated to a charge transfer kinetic mechanism influenced by surface states and the p-type substrate. The latter most likely due to the space charge region extending beyond the absorber layer reaching the substrate. Current density-potential and electrochemical impedance spectroscopy measurements in dark revealed a reduction of the SiO2 native layer at cathodic potentials higher than -1 V vs. Ag/AgCl (3.5 M KCl), which contributes to the high charge transfer kinetic of the system. We believe that these results will contribute to understand the substrate influence in the PEC performance of top absorber layers in multilayer structures for solar water splitting.This research was funded by FONDECYT (National Fund for Scientific, Technological Development and Technological Innovation) under the agreement 147-2017. The author M Mejia has been supported by the CONCYTEC Peru (National Council for Science, Technology and Technological Innovation) doctoral scholarship under the Contract Number 236-2015-FONDECYT as well as by the PUCP vicechancellorship for research (VRI, Project No. CAP-2019-3-0041/702). The authors would like to thank the Katholischer Akademischer Auslander-Dienst institution (KAAD) for the short-term grants given to conduct research internships in the Technische Universitat Ilmenau (TU Ilmenau). Finally, the authors would like to thank the German Research Foundation (DFG) (DFG-Gz: INST 273/56-1 FUGG) and the Materials Characterization Center (CAM) at PUCP, for the financial support to conduct the characterization experiments