In-beam study of102Sn

Excited states in¹⁰²Sn have been identified for the first time, in an in-beamγ-ray spectroscopic experiment. Twoγ-ray transitions with energies 1472 and 497 keV following the decay of the seniority 6⁺ isomer with t_1/2=1.0(5)μs were unambiguously assigned to¹⁰²Sn. Due to the very low cross section of about 2µb for producing¹⁰²Sn in the reaction⁵⁰Cr(⁵⁸Ni,1α2n), a highly selective detector setup utilizing NORDBALL ancillary detectors and a recoil catcher device was used. Highγ-ray detection efficiency was achieved with two EUROBALL Ge cluster detectors.     

Fluid-velocity measurements and flow-pattern identification by noise-analysis of light-beam signals

For fluid-velocity measurements of the two-phase flow in reactor safety experiments, a new method has been developed. This method is based on cross-correlating the signals of two light-beam detectors, which cross the diameter of the test-section (no flow restriction).

Furthermore, the signals of the two detectors are also used to give a rough estimate of the flow-pattern of the investigated two-phase flow. This flow-pattern identification is performed by comparing several characteristic functions (like the spectra and probability-functions of the signals) of a known flow-pattern recorded in an air-water test-facility, with equivalent functions of the investigated two-phase flow. This flow-pattern identification is performed by comparing several characteristic functions (like the spectra and probability-functions of the signals) of a known flow-pattern recorded in an air-water test-facility, with equivalent functions of the investigated two-phase flow. An important requirement for these comparisons is the appropriate normalization of the abscissa of the characteristic-functions, which is performed with the time-averaged fluid velocity.

As an example, the results of a blow-down experiment are shown. Velocities up to 300 m/s could be measured within a pressure range up to 50 bars and temperatures up to 280°C. Flow-regime changes were observed in three different parts of the blow-down.     

Observation of superfluid flow in a bose-einstein condensed Gas

We have studied the hydrodynamic flow in a Bose-Einstein condensate stirred by a macroscopic object, a blue-detuned laser beam, using nondestructive in situ phase contrast imaging. A critical velocity for the onset of a pressure gradient has been observed, and shown to be density dependent. The technique has been compared to a calorimetric method used previously to measure the heating induced by the motion of the laser beam.     

Globally attractive oscillations in open monosubstrate allosteric enzyme reactions

Here we study the dynamical properties of glycolytic and other similar biochemical oscillation-generating processes by means of the analysis of a model proposed by Golbdeter and Lefever (Bioph J 13:1302–1315, 1972) in a reduced form proposed by Keener and Sneyd (Mathematical physiology, chap 1, Springer Verlag, Berlin, 2009). After showing that the orbits of the system are bounded, we give some conditions for the existence of oscillations and for the global arrest of them. Then, after deriving an equivalent Lienard-Newton’s equation we assess uniqueness and the global stability of the arising limit cycle. Finally, we shortly investigate the possibility of breaking of the spatial symmetry. Some biological remarks end the work.     

Nuclear spectroscopy near the proton drip line in the lanthanide region: The122La nucleus

Excited states in the very neutron-deficient¹²²La nucleus have been established for the first time using the⁹²Mo(⁴⁰Ca, 2α1p1n) reaction at beam energies of 190 and 200MeV. The observed transitions were grouped in three bands. Configurations have been assigned to the observed bands based on the properties extracted from the experimental data and on cranked shell model calculations.     

Spin-alignment and g-factor measurement of the I^{\pi} = 12+ isomer in 192Pb produced in the relativistic-energy fragmentation of a 238U beam

Reactions of a 16.8 MeV ⁶He beam with a ⁹Be target have been investigated using highly segmented detector setup covering a large solid angle. Data on elastic and quasi-free scattering, as well as two-neutron transfer, are reported. The results for elastic scattering are fairly well reproduced by a CDCC calculation, in agreement with the interpretation of a breakup effect already observed for the scattering of ⁶He on other light targets. Exotic quasi-free scattering of ⁶He on $ \alpha$ -cluster in ⁹Be is clearly observed. Inclusive and coincident events were used to extract information on the two-neutron transfer reaction ⁹Be(⁶He, $ \alpha$ )¹¹Be . Sequential decay of the ¹¹Be state at the excitation energy $\ensuremath E_x = 10.6$ MeV through different channels is discussed.     

Traveling Wave Solutions to the Free Boundary Incompressible Navier-Stokes Equations

In this paper we study a finite-depth layer of viscous incompressible fluid in dimension $n\ge 2$, modeled by the Navier-Stokes equations. The fluid is assumed to be bounded below by a flat rigid surface and above by a free, moving interface. A uniform gravitational field acts perpendicularly to the flat surface, and we consider the cases with and without surface tension acting on the free interface. In addition to these gravity-capillary effects, we allow for a second force field in the bulk and an external stress tensor on the free interface, both of which are posited to be in traveling wave form, i.e., time-independent when viewed in a coordinate system moving at a constant velocity parallel to the rigid lower boundary. We prove that, with surface tension in dimension $n\ge 2$ and without surface tension in dimension $n=2$, for every nontrivial traveling velocity there exists a nonempty open set of force and stress data that give rise to traveling wave solutions. While the existence of inviscid traveling waves is well-known, to the best of our knowledge this is the first construction of viscous traveling wave solutions. Our proof involves a number of novel analytic ingredients, including: the study of an overdetermined Stokes problem and its underdetermined adjoint problem, a delicate asymptotic development of the symbol for a normal-stress to normal-Dirichlet map defined via the Stokes operator, a new scale of specialized anisotropic Sobolev spaces, and the study of a pseudodifferential operator that synthesizes the various operators acting on the free surface functions. © 2022 The Authors. Communications on Pure and Applied Mathematics published by Wiley Periodicals LLC.