229 research outputs found
A Statement of Purpose
This document contains the statement of purpose of the first volume of The Bridge: A Yearbook of Judaeo-Christian Studies, which was edited by John M. Oesterriecher and Barry Ulanov
A Statement of Purpose
This document contains the statement of purpose of the first volume of The Bridge: A Yearbook of Judaeo-Christian Studies, which was edited by John M. Oesterriecher and Barry Ulanov
Local structure of divalent silver complexes in fluorite crystals as seen by EPR method
The analytical expressions for spin-Hamiltonian parameters of Jahn-Teller paramagnetic centres [AgF2F6]6- in fluorite crystals are deduced. Comparison with the experimental EPR data for CdF2, CaF2 and SrF2 yields information about the local structure of centres [AgF2F6]6-. It is found that two Ag2+-F- bonds of the centre (along the 〈111〉 direction) are shorter than the rest six bonds by factor 1.1. Euler angles of six non-axial fluorines are almost the same as those in the undistorted fluorite structure. © Springer-Verlag 1998 Printed in Austria
The second Konus-Wind catalog of short gamma-ray bursts
In this catalog, we present the results of a systematic study of 295 short
gamma-ray bursts (GRBs) detected by Konus-Wind (KW) from 1994 to 2010. From the
temporal and spectral analyses of the sample, we provide the burst durations,
the spectral lags, the results of spectral fits with three model functions, the
total energy fluences and the peak energy fluxes of the bursts. We discuss
evidence found for an additional power-law spectral component and the presence
of extended emission in a fraction of the KW short GRBs. Finally, we consider
the results obtained in the context of the Type I (merger-origin) / Type II
(collapsar-origin) classifications.Comment: Accepted to the Astrophysical Journal Supplement Series (7 Figures, 8
Tables
Konus-Wind and Helicon-Coronas-F Observations of Solar Flares
Results of solar flare observations obtained in the Konus-Wind experiment
from November, 1994 to December, 2013 and in the Helicon Coronas-F experiment
during its operation from 2001 to 2005, are presented. For the periods
indicated Konus-Wind detected in the trigger mode 834 solar flares, and
Helicon-Coronas-F detected more than 300 solar flares.
A description of the instruments and data processing techniques are given. As
an example, the analysis of the spectral evolution of the flares
SOL2012-11-08T02:19 (M 1.7) and SOL2002-03-10T01:34 (C5.1) is made with the
Konus-Wind data and the flare SOL2003-10-26T06:11 (X1.2) is analyzed in the
2.223 MeV deuterium line with the Helicon-Coronas-F data.Comment: Published version. A list of the Konus-Wind solar flare triggers and
figures of their time profiles are available at
http://www.ioffe.ru/LEA/Solar
AM-FFF of Objects Using Commercial PLA Based Shape Memory Polymer Printed by an Open-Source 3D Printer
The 4D additive manufacturing processes are considered today as the "next big thing" in R&D. The aim of this research is to provide two examples of commercial PLA based shape memory polymer (SMP) objects printed on an open-source 3D printer in order to proof the feasibility of such novel 4D printing process. To that purpose, a PLA based filament of eSUN (4D filament e4D-1white, SMP) was chosen, and two applications, a spring and a vase, were designed by 3D-printing with additive manufacturing (AM) fused filament fabrication (FFF) technique. The 4D-printed objects were successfully produced, the shape memory effect and their functionality were demonstrated by achieving the shape-memory cycle of programming, storage and recovery
Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal
A methodology is worked out to retrieve the numerical values of all the main
parameters of the six-dimensional adiabatic potential energy surface (APES) of
a polyatomic system with a quadratic T-term Jahn-Teller effect (JTE) from
ultrasound experiments. The method is based on a verified assumption that
ultrasound attenuation and speed encounter anomalies when the direction of
propa- gation and polarization of its wave of strain coincides with the
characteristic directions of symmetry breaking in the JTE. For the SrF2:Cr
crystal, employed as a basic example, we observed anomaly peaks in the
temperature dependence of attenuation of ultrasound at frequencies of 50-160
MHz in the temperature interval of 40-60 K for the wave propagating along the
[110] direction, for both the longitudinal and shear modes, the latter with two
polarizations along the [001] and [110] axes, respectively. We show that these
anomalies are due to the ultrasound relaxation by the system of non-interacting
Cr2+ JT centers with orthorhombic local distortions. The interpretation of the
ex- perimental findings is based on the T2g (eg +t2g) JTE problem including the
linear and quadratic terms of vibronic interactions in the Hamiltonian and the
same-symmetry modes reduced to one interaction mode. Combining the experimental
results with a theoretical analysis we show that on the complicated
six-dimensional APES of this system with three tetragonal, four trigonal, and
six orthorhombic extrema points, the latter are global minima, while the former
are saddle points, and we estimate numerically all the main parameters of this
surface, including the linear and quadratic vibronic coupling constants, the
primary force constants, the coordinates of all the extrema points and their
energies, the energy barrier between the orthorhombic minima, and the tunneling
splitting of the ground vibrational states.Comment: 8 pages, 3 figure
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