17,813 research outputs found
Thermophysical properties in the system Li-Pb. Part II: Thermophysical properties of Li(17)Pb(83) eutectic alloy
The Herschel Space Observatory view of dust in M81
We use Herschel Space Observatory data to place observational constraints on the peak and Rayleigh-Jeans slope of dust emission observed at 70−500 μm in the nearby spiral galaxy M81. We find that the ratios of wave bands between 160 and 500 μm are primarily dependent on radius but that the ratio of 70 to 160 μm emission shows no clear dependence on surface brightness or radius. These
results along with analyses of the spectral energy distributions imply that the 160−500 μm emission traces 15−30 K dust heated by evolved stars in the bulge and disc whereas the 70 μm emission includes dust heated by the active galactic nucleus and young stars in star forming regions
Surveys of Galaxy Clusters with the Sunyaev Zel'dovich Effect
We have created mock Sunyaev-Zel'dovich effect (SZE) surveys of galaxy
clusters using high resolution N-body simulations. To the pure surveys we add
`noise' contributions appropriate to instrument and primary CMB anisotropies.
Applying various cluster finding strategies to these mock surveys we generate
catalogues which can be compared to the known positions and masses of the
clusters in the simulations. We thus show that the completeness and efficiency
that can be achieved depend strongly on the frequency coverage, noise and beam
characteristics of the instruments, as well as on the candidate threshold. We
study the effects of matched filtering techniques on completeness, and bias. We
suggest a gentler filtering method than matched filtering in single frequency
analyses. We summarize the complications that arise when analyzing the SZE
signal at a single frequency, and assess the limitations of such an analysis.
Our results suggest that some sophistication is required when searching for
`clusters' within an SZE map.Comment: 8 pages, 7 figure
Development of a germanium-68 radionuclide production technology by irradiation of enriched isotope zinc-66 in the R7M
In the present study, we performed the evaluation and experimental determination of 68Ge production using alpha particle beams in the R7M cyclotron of the Tomsk Polytechnic University
In-Plane Conductivity Anisotropy in Underdoped Cuprates in the Spin-Charge Gauge Approach
Applying the recently developed spin-charge gauge theory for the pseudogap
phase in cuprates, we propose a self-consistent explanation of several peculiar
features of the far-infrared in-plane AC conductivity, including a broad peak
as a function of frequency and significant anisotropy at low temperatures,
along with a similar temperature-dependent in-plane anisotropy of DC
conductivity in lightly doped cuprates. The anisotropy of the metal-insulator
crossover scale is considered to be responsible for these phenomena. The
obtained results are in good agreement with experiments. An explicit proposal
is made to further check the theory.Comment: 5 pages, 3 figures, to appear in Phys. Rev.
Fission decay of N = Z nuclei at high angular momentum: Zn
Using a unique two-arm detector system for heavy ions (the BRS, binary
reaction spectrometer) coincident fission events have been measured from the
decay of Zn compound nuclei formed at 88MeV excitation energy in the
reactions with Ar beams on a Mg target at Ar) =
195 MeV. The detectors consisted of two large area position sensitive (x,y) gas
telescopes with Bragg-ionization chambers. From the binary coincidences in the
two detectors inclusive and exclusive cross sections for fission channels with
differing losses of charge were obtained. Narrow out-of-plane correlations
corresponding to coplanar decay are observed for two fragments emitted in
binary events, and in the data for ternary decay with missing charges from 4 up
to 8. After subtraction of broad components these narrow correlations are
interpreted as a ternary fission process at high angular momentum through an
elongated shape. The lighter mass in the neck region consists dominantly of two
or three-particles. Differential cross sections for the different mass splits
for binary and ternary fission are presented. The relative yields of the binary
and ternary events are explained using the statistical model based on the
extended Hauser-Feshbach formalism for compound nucleus decay. The ternary
fission process can be described by the decay of hyper-deformed states with
angular momentum around 45-52 .Comment: 23 pages, 25 figure
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