We show that hadronization via quark coalescence enhances hadron elliptic flow at large p(perpendicular) relative to that of partons at the same transverse momentum. Therefore, compared to earlier ...results based on covariant parton transport theory, more moderate initial parton densities dN/deta(b=0) approximately 1500-3000 can explain the differential elliptic flow v(2)(p(perpendicular)) data for Au+Au reactions at sqrts=130 and 200A GeV from BNL RHIC. In addition, v(2)(p(perpendicular)) could saturate at about 50% higher values for baryons than for mesons. If strange quarks have weaker flow than light quarks, hadron v(2) at high p(perpendicular) decreases with relative strangeness content.
Using a hydrodynamic model, we predict the transverse momentum dependence of the spectra and the elliptic flow for different hadrons in Au+Au collisions at
s
=130
A
GeV. The dependence of the ...differential and
p
t
-integrated elliptic flow on the hadron mass, equation of state and freeze-out temperature is studied both numerically and analytically.
Cobalt and iron(II) hexachloroclathrochelates with apical aliphatic and aromatic substituents were synthesized and characterized using cyclic voltammetry. The obtained clathrochelate-based systems ...were impregnated on the surface of carbon paper and tested as cathode electrocatalysts in water electrolysis cell with proton exchange membrane (PEM). Both the cyclic voltammograms and the current–voltage performances of membrane-electrode assemblies suggested that these cage complexes can be successfully implemented in PEM water electrolyzers and used as efficient electrocatalysts for hydrogen evolution.
Synthesis of the Co and Fe hexachloroclathrochelates and corresponding current–voltage performances of PEM water electrolysis cell. Display omitted
•Alkyl- and arylboron-capped Co and Fe hexachloroclathrochelates were synthesized.•Clathrochelate-based electrocatalysts were implemented in PEM water electrolysis.•Fe and Co clathrochelate complexes were successfully used as efficient HER catalysts.•Best performances were observed with electrocatalyst based on iron(II) cage complex.
At the very first stage of an ultra-relativistic nucleus–nucleus collision new particles are produced in individual nucleon–nucleon collisions. In the transverse plane, all particles from a single NN ...collision are initially located at the same position. The subsequent thermalization and transverse radial expansion of the system create strong position-momentum correlations and lead to characteristic rapidity, transverse momentum, and azimuthal correlations among the produced particles.
We present a novel method allowing high-power single-frequency emission with sub-kHz linewidth from a compact multi-frequency diode laser locked to high-Q optical microresonator. Using high-Q MgF
...microresonator and multi-frequency diode laser operating at 1535 nm with the output power of 100 mW and an emission spectrum consisting of approximately 50 lines with MHz linewidth, we observed a spectrum collapse to a single line or several lines with a sub-kHz linewidth and output power power of 50 mW. The Bogatov effect predicted more than 30 years ago was observed and studied in the spectrum of the locked laser. For analysis of the considered effect, original theoretical model taking into account self-injection locking effect, mode competition and Bogatov asymmetric mode interaction was developed and numerical modeling was performed. All numerical results are in a good agreement with our experimental data. Accurate analytical estimations for the parameters critical for the considered effect were obtained. The proposed method may be applied for different types of diode lasers operating in different spectral ranges.
The dependence of the nature of electromagnetically induced transparency (EIT) in gas cells without a buffer gas on the quality of the antirelaxation coating of the walls, i.e., on the probability of ...relaxation of the internal state of an atom upon collision with this coating, is analyzed. It is found that, in a number of practically important cases, relaxation on the walls has little effect on the contrast of the EIT resonance, and, under certain conditions, even enhances this effect. For a nondegenerate ground state of atoms, the significant difference is analyzed between two schemes for the implementation of EIT in the cases of Stokes and anti-Stokes scattering of probe radiation, as well as between two types of reflection, specular (elastic) and diffuse, when the atom velocity after reflection does not depend on the velocity before the collision but is determined by the wall temperature. Particular attention is paid to the features of the EIT spectra when the nondegeneracy of the excited state of atoms is taken into account.
The spin state of the cobalt(II) phenylborate hexa-
n-
butylsulfide clathrochelate in solutions is studied by paramagnetic NMR spectroscopy. This cage complex is shown to undergo the ...temperature-induced spin transition in solvents of different nature (acetonitrile, chloroform, dichloromethane, and benzene). The previously developed method for an analysis of paramagnetic shifts in NMR spectra allows the determination of the thermodynamic parameters (enthalpy and entropy) of the spin equilibrium in the solutions. In spite of the conformational rigidity of the macrobicyclic tris(dioximate) molecules, substantial changes in the electronic structures and spin equilibrium parameters are observed depending on the polarity of the solvent used. This provides opportunities for fine tuning of spin switch characteristics by changing this parameter of the medium.
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