385 research outputs found
Pressure dependence of the thermoelectric power of single-walled carbon nanotubes
We have measured the thermoelectric power (S) of high purity single-walled
carbon nanotube mats as a function of temperature at various hydrostatic
pressures up to 2.0 GPa. The thermoelectric power is positive, and it increases
in a monotonic way with increasing temperature for all pressures. The low
temperature (T < 40 K) linear thermoelectric power is pressure independent and
is characteristic for metallic nanotubes. At higher temperatures it is enhanced
and though S(T) is linear again above about 100 K it has a nonzero intercept.
This enhancement is strongly pressure dependent and is related to the change of
the phonon population with hydrostatic pressure.Comment: 4 pages, 3 figure
Observation of Resonant Diffusive Radiation in Random Multilayered Systems
Diffusive Radiation is a new type of radiation predicted to occur in randomly
inhomogeneous media due to the multiple scattering of pseudophotons. This
theoretical effect is now observed experimentally. The radiation is generated
by the passage of electrons of energy 200KeV-2.2MeV through a random stack of
films in the visible light region. The radiation intensity increases resonantly
provided the Cherenkov condition is satisfied for the average dielectric
constant of the medium. The observed angular dependence and electron resonance
energy are in agreement with the theoretical predictions. These observations
open a road to application of diffusive radiation in particle detection,
astrophysics, soft X-ray generation and etc.. `Comment: 4pages, 4figure
The metastasis associated protein S100A4: role in tumour progression and metastasis
The metastasis associated protein S100A4 is a small calcium binding protein that is associated with metastatic tumors and appears to be a molecular marker for clinical prognosis. Below we discuss its biochemical properties and possible cellular functions in metastasis including cell motility, invasion, apoptosis, angiogenesis and differentiation
Structure and cooling of compact stars
We study the structure and evolution of neutron stars (NS) the interiors of
which are modeled using microscopic approaches and constrained by the condition
that the equation of state (EoS) of matter extrapolated to high densities
should not contradict known observational data from compact stars and
experimental data from heavy-ion collisions (HIC). We use modern cooling
simulations to extract distributions of NS masses required to reproduce those
of the yet sparse data in the Temperature-Age (TA) plane. By comparing the
results with a mass distribution for young, nearby NSs used in population
synthesis we can sharpen the NS cooling constraints.Comment: 22 pages, 9 figures, Lecture notes for the Helmholtz International
Summer School on "Dense Matter in Heavy-Ion Collisions and Astrophysics",
JINR, Dubna, August 21 - September 1, 200
The phase diagram of three-flavor quark matter under compact star constraints
The phase diagram of three-flavor quark matter under compact star constraints
is investigated within a Nambu--Jona-Lasinio model. Local color and electric
charge neutrality is imposed for beta-equilibrated superconducting quark
matter. The constituent quark masses and the diquark condensates are determined
selfconsistently in the plane of temperature and quark chemical potential. Both
strong and intermediate diquark coupling strengths are considered. We show that
in both cases, gapless superconducting phases do not occur at temperatures
relevant for compact star evolution, i.e., below T ~ 50 MeV. The stability and
stucture of isothermal quark star configurations are evaluated. For
intermediate coupling, quark stars are composed of a mixed phase of normal (NQ)
and two-flavor superconducting (2SC) quark matter up to a maximum mass of 1.21
M_sun. At higher central densities, a phase transition to the three-flavor
color flavor locked (CFL) phase occurs and the configurations become unstable.
For the strong diquark coupling we find stable stars in the 2SC phase, with
masses up to 1.326 M_sun. A second family of more compact configurations
(twins) with a CFL quark matter core and a 2SC shell is also found to be
stable. The twins have masses in the range 1.301 ... 1.326 M_sun. We consider
also hot isothermal configurations at temperature T=40 MeV. When the hot
maximum mass configuration cools down, due to emission of photons and
neutrinos, a mass defect of 0.1 M_sun occurs and two final state configurations
are possible.Comment: 12 pages, 11 figure
Five problems in legal maintenance of IT projects
Objective: to assess the compliance of traditional approaches to IT projects legal maintenance with the modern methods of organizing the process of digital products development, to identify the existing problems in this area and suggest possible ways to resolve them. Methods: the research used the logical method and the method of analyzing judicial practice, the inductive method, the method of comparison, and the method of scientific abstraction. Results: digitalization facilitated the development of the services market for IT projects and their maintenance. Legal maintenance of such projects often faces a significant discrepancy between the positions of the customer and the contractor, especially when part of the project is accomplished. Based on the analysis of judicial practice of IT projects using the Agile methodology, the most significant and problematic legal aspects of implementation were identified, and conflict situations between customers and performers of IT projects were analyzed.Scientific novelty: five key problems of IT projects legal maintenance that use flexible management methods are identified. A universal model for implementing legal functions in Agile projects is proposed.Practical significance: the proposed scheme of legal maintenance of IT projects can be used to regulate the legal relationships of their participants and may help to reduce the conflict level and speed up the process of digital products development using the Agile methodology
First results from the NA60 experiment at CERN
Since 1986, several heavy ion experiments have studied some signatures of the
formation of the quark-gluon plasma and a few exciting results have been found.
However, some important questions are still unanswered and require new
measurements. The NA60 experiment, with a new detector concept that vastly
improves dimuon detection in proton-nucleus and heavy-ion collisions, studies
several of those open questions, including the production of open charm. This
paper presents the experiment and some first results from data collected in
2002.Comment: Paper presented at the XXXVIII Rencontres de Moriond, QCD and High
Energy Hadronic Interactions, Les Arcs, March 22-29, 2003. 4 pages, 6 figure
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