1,157 research outputs found
The Half-lives of La and La
The half-lives of La and La were determined via gamma
spectroscopy and high-precision ionization chamber measurements. The results
are 18.930(6) h for La and 4.59(4) h for La compared to the
previously compiled values of 19.5(2) h and 4.8(2) h, respectively. The new
results represent an improvement in the precision and accuracy of both values.
These lanthanum isotopes comprise a medically interesting system with positron
emitter La and Auger electron emitter La forming a matched pair
for internal diagnostics and therapeutics. The precise half-lives are necessary
for proper evaluation of their value in medicine and for a more representative
tabulation of nuclear data.Comment: 11 pages, 3 figure
A Few Suggestions on the Care of the Eggs and the Rearing of the Walking-Stick, Diapheromera femorata
Three variable exponential functions of the alternating group
New class of special functions of three real variables, based on the
alternating subgroup of the permutation group , is studied. These
functions are used for Fourier-like expansion of digital data given on lattice
of any density and general position. Such functions have only trivial analogs
in one and two variables; a connection to the functions of is shown.
Continuous interpolation of the three dimensional data is studied and
exemplified.Comment: 10 pages, 3 figure
Evolution of nano-pores during annealing of technically pure molybdenum sheet produced from different sintered formats
Molybdenum is a refractory metal with no phase transformation in the solid state and a high melting point. It is therefore an excellent structural material for various high temperature applications. Especially in this field of operation, significant creep resistance is essential. To achieve this, a microstructure with grains in the range of millimeters is desired. However, as demonstrated in the present study, the onset temperature for secondary recrystallization, which would lead to a beneficial grain size, is among other things dependent on the initial dimensions of the sintered part. One possible reason for the different microstructural evolutions is the influence of residual pores in sub-micrometer size. Sheets were thus fabricated via three different production routes employing the same initial Mo powder to exclude chemical variation as an influencing factor. The samples were investigated by in-situ small-angle X-ray scattering at a synchrotron radiation source with two different heating rates. Additionally, selected annealed samples were studied ex-situ with high energy X-rays. The apparent volume fraction of pores is compared to a volatilization model for the vaporization of typical accompanying elements and the induced thermal expansion
Band-theoretical prediction of magnetic anisotropy in uranium monochalcogenides
Magnetic anisotropy of uranium monochalcogenides, US, USe and UTe, is studied
by means of fully-relativistic spin-polarized band structure calculations
within the local spin-density approximation. It is found that the size of the
magnetic anisotropy is fairly large (about 10 meV/unit formula), which is
comparable with experiment. This strong anisotropy is discussed in view of a
pseudo-gap formation, of which crucial ingredients are the exchange splitting
of U 5f states and their hybridization with chalcogen p states (f-p
hybridization). An anomalous trend in the anisotropy is found in the series
(US>>USe<UTe) and interpreted in terms of competition between localization of
the U 5f states and the f-p hybridization. It is the spin-orbit interaction on
the chalcogen p states that plays an essential role in enlarging the strength
of the f-p hybridization in UTe, leading to an anomalous systematic trend in
the magnetic anisotropy.Comment: 4 pages, 5 figure
Broadside radar echoes from ionized trails
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77210/1/AIAA-2347-553.pd
Nasopharyngeal carriage of Streptococcus pneumonia in pneumonia-prone age groups in Semarang, Java Island, Indonesia
Introduction: Streptococcus pneumoniae is a worldwide occurring pathogen Nasopharyngeal carriage of Streptococcus pneumoniae precedes pneumonia and other pneumococcal diseases in the community. Little is known about S. pneumoniae carriage in Indonesia, complicating strategies to control pneumococcal diseases. We investigated nasopharyngeal carriage of S. pneumoniae in Semarang, Indonesia. Methods: A population-based survey was performed in Semarang, Indonesia. Nasopharyngeal swabs and questionnaires were taken from 496 healthy young (6-60 month-old) children and 45-70 year-old adults. Results: Forty-three percent of children aged 6-60 months and 11% of adults aged 45-75 years carried S. pneumoniae. Determinants of carriage were being a child (OR 7.7; 95
Heterometallic Bromo-bridged Complexes with a Re(CO)3 Fragment
Heterobimetallic complexes where half-sandwich complexes of ruthenium(II), rhodium(III) and iridium(III) are connected by three bromo-bridges to Re(CO)3 have been prepd. from metathesis reactions of [RuBr(m-Br)(h6-arene)]2 (arene = C6H6, C6H3Et3-1,3,5 or p-cymene) or [MBr(m-Br)Cp*]2 (M = Rh or Ir) with [Re(m-Br)(CO)3(C4H8O)]2. The crystal structures of [(h6-arene)Ru(m-Br)3Re(CO)3] (arene = C6H6 or C6H3Et3-1,3,5) and [Cp*M(m-Br)3Re(CO)3] (M = Rh or Ir) have been detd. by X-ray anal. In soln. all complexes were in dynamic equil. with isomeric ionic compds. of general formula [M2(m-Br)3(p-ligand)2][Re2(m-Br)3(CO)6] (M = Ru, Rh or Ir). The solid state structures of [Ru2(m-Br)3(h6-C6H3Et3-1,3,5)2][Re2(m-Br)3(CO)6] and [Ru2(m-Br)3(h6-p-MeC6H4Pri)][Re2(m-Br)3(CO)6] are described
Magnetic phases near the Van Hove singularity in s- and d-band Hubbard model
We investigate the magnetic instabilities of the nondegenerate (s-band) and a
degenerate (d-band) Hubbard model in two dimensions using many-body effects due
to the particle-particle diagrams and Hund's rule local correlations. The
density of states and the position of Van Hove singularity change depending on
the value of next-nearest neighbor hopping t'. The Stoner parameter is strongly
reduced in the s-band case, and ferromagnetism survives only if electron
density is small, and the band is almost flat at small momenta due to
next-nearest neighbor hopping. In contrast, for the d-band case the reduction
of the Stoner parameter which follows from particle-particle correlations is
much smaller and ferromagnetism survives to a large extent. Inclusion of local
spin-spin correlations has a limited destabilizing effect on the magnetic
states.Comment: 8 pages, 7 figure
- …