Universal pion freeze-out in heavy-ion collisions

Based on an evaluation of data on pion interferometry and on particle yields at midrapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda(f) reaches a value of about 1 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and beam energy from the Alternating Gradient Synchrotron to the Relativistic Heavy Ion Collider.     

The lithium- and sodium-enhanced transformation of Ba-exchanged zeolite LTA into celsian phase

The Li⁺- and Na⁺-doped hexacelsians (HC) synthesized from Ba-LTA synthetic zeolite as precursors were used for preparation of monoclinic celsians (MC). The doped pure MC and mixture HC/MC species were obtained by thermally induced polymorphous transformation at 1200 °C. Synthesized-doped MC have been characterized by X-ray powder diffraction and spectroscopic (infrared, Raman and ²⁹Si magic angle spinning nuclear magnetic resonance) methods. The obtained results suggest that in all investigated samples Na⁺ or Li⁺ dopants were incorporated in MC crystal structures during thermal transformation of a zeolite. It has been shown that HC→MC transformation depends on molar fractions of alkali cations. These findings combined with used temperature/time conditions could help in optimization of MC synthesis route.     

Coexistence of Spin–Lattice Relaxation and Phonon-Bottleneck Processes in GdIII–Phthlocyaninato Triple-Decker Complexes under Highly Diluted Conditions

Gd³⁺ complexes have been shown to undergo unusual slow magnetic relaxation processes similar to those of single-molecule magnets (SMMs), even though Gd³⁺ does not exhibit strong magnetic anisotropy. To reveal the origin of the slow magnetic relaxation of Gd³⁺ complexes, we have investigated the magnetic properties and heat capacities of two Gd³⁺-phthalocyaninato triple-decker complexes, one of which has intramolecular Gd³⁺–Gd³⁺ interactions and the other does not. It was found that the Gd³⁺–Gd³⁺ interactions accelerate the magnetic relaxation processes. In addition, magnetically diluted samples, prepared by doping a small amount of the Gd³⁺ complexes into a large amount of diamagnetic Y³⁺ complexes, underwent dual magnetic relaxation processes. A detailed dynamic magnetic analysis revealed that the coexistence of spin–lattice relaxation and phonon-bottleneck processes is the origin of the dual magnetic relaxation processes.     

Abelian actions with globally hypoelliptic leafwise Laplacian and rigidity

In this paper, we prove several results concerning smooth R^k actions on a smooth compact manifold with the property that their leafwise Laplacian is globally hypoelliptic. Such actions are necessarily uniquely ergodic and minimal, and their cohomology is often finite dimensional, even trivial. Further, we consider a class of examples of R² actions on two-step nilmanifolds that have globally hypoelliptic leafwise Laplacian, and we show transversal local rigidity under certain Diophantine conditions.     

COMMON FIXED POINT THEOREMS FOR MULTI-VALUED MAPS

We establish some results on coincidence and common fixed points for a twopair of multi-valued and single-valued maps in complete metric spaces.Presented theorems generalize recent results of Gordji et...     

Fixed point and common fixed point theorems on ordered cone metric spaces

In the present work, some fixed point and common fixed point theorems for self-maps on ordered cone metric spaces, where the cone is not necessarily normal, are proved.     

Ground-state entropy of Ising antiferromagnets with general spinS

We present a simple method to obtain reliable ground-state entropies of Ising antiferromagnets in a maximum critical field. As an example, the ground-state entropy for the square lattice is established for allS. Both the case of the first-, and of the second-neighbour interactions are considered.     

Temperature-programmed desorption of n-hexane from hydrated HZSM-5 and NH4ZSM-5 zeolites

Temperature-programmed desorption coupled with mass spectrometer as a detector (TPD), IR and ¹³C NMR measurements are used to study the adsorption of n-hexane on hydrated HZSM-5 and NH₄ZSM-5 zeolites. The ¹³C NMR measurements show that n-hexane can access the pore structure of ZSM-5 zeolites previously saturated with water. TPD spectra of n-hexane are monitored in the temperature region 50–300°C, in the case of fully or partially hydrated samples; two-stage desorption of n-hexane is found. Simultaneous desorption of water and n-hexane in the same temperature region are found, in all investigated samples.     

Slow Magnetic Relaxation and Single‐Molecule Toroidal Behaviour in a Family of Heptanuclear {CrIIILnIII6} (Ln=Tb,Ho, Er) Complexes

The synthesis, magnetic properties, and theoretical studies of three heterometallic {Cr^IIILn^III₆} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln₃ triangles connected via a Cr^III linker, are reported. The {CrTb₆} and {CrEr₆} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single‐crystal measurements reveal opening up of the hysteresis loop for {CrTb₆} and {CrHo₆} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln₃ triangles, which are found to couple, stabilizing a con‐rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non Dy^III complexes for the first time.