4,956 research outputs found
Dosimetrie van Heelliggaamsbestraling met Elektrone vir die Behandeling van Mycosis Fungoides
A six-field method for whole-body radiation with 3,4 MeV electrons obtained from a Mevatron 8 linear accelerator, is described. The physical properties of the electrons are given, and a method is described whereby the wholebody isodose distributions can be predicted during wholebody irradiation
Purchasing superior-value offerings effectively and successfully
In business markets price still plays a significant part in selling
and buying decisions. Suppliers strive to get an equitable or fair
return on the value of their offerings and buyers look for bargains
and usually find them, thanks to over-eager suppliers. However,
recent experiments show that there are other more effective and
successful ways of selling witho
Modulated Amplitude Waves in Bose-Einstein Condensates
We analyze spatio-temporal structures in the Gross-Pitaevskii equation to
study the dynamics of quasi-one-dimensional Bose-Einstein condensates (BECs)
with mean-field interactions. A coherent structure ansatz yields a
parametrically forced nonlinear oscillator, to which we apply Lindstedt's
method and multiple-scale perturbation theory to determine the dependence of
the intensity of periodic orbits (``modulated amplitude waves'') on their wave
number. We explore BEC band structure in detail using Hamiltonian perturbation
theory and supporting numerical simulations.Comment: 5 pages, 4 figs, revtex, final form of paper, to appear in PRE
(forgot to include \bibliography command in last update, so this is a
correction of that; the bibliography is hence present again
‘Drone’: technically correct, popularly accepted, socially acceptable
The Journal of Unmanned Vehicle Systems—led by its founding editor, David Bird—published its first issue in December 2013. It was the first peer-reviewed scientific journal entirely dedicated to research relating to all types of remotely piloted or autonomous robotic vehicles, including those that operate in the air, on the ground, or on or below the water’s surface. Although rare currently, it could also expand to include those that operate in outer space environments (Potter 2020). This is a uniquely eclectic field of research that encompasses multiple engineering and design aspects of the vehicles themselves in addition to a diverse and ever-growing array of practical applications of the technology..
Angra Neutrino Project: status and plans
We present the status and plans of the Angra Project, a new nuclear reactor
neutrino oscillation experiment, proposed to be built in Brazil at the Angra
dos Reis nuclear reactor complex. This experiment is aimed to measure theta_13,
the last unknown of the three neutrino mixing angles. Combining a high
luminosity design, very low background from cosmic rays and careful control of
systematic errors at the 1% level, we propose a high sensitivity multi-detector
experiment, able to reach a sensitivity to antineutrino disappearance down to
sin^2(2*theta_13) = 0.006 in a three years running period, improving present
limits constrained by the CHOOZ experiment by more than an order of magnitude.Comment: 2 pages, 1 figure, talk presented by J.C. Anjos ([email protected]) at
NuFact05, 21-26 June 2005, Frascati, Ital
A general perspective of the characterization and quantification of nanoparticles: Imaging, spectroscopic, and separation techniques
This article gives an overview of the different techniques used to identify, characterize, and quantify engineered nanoparticles (ENPs). The state-of-the-art of the field is summarized, and the different characterization techniques have been grouped according to the information they can provide. In addition, some selected applications are highlighted for each technique. The classification of the techniques has been carried out according to the main physical and chemical properties of the nanoparticles such as morphology, size, polydispersity characteristics, structural information, and elemental composition. Microscopy techniques including optical, electron and X-ray microscopy, and separation techniques with and without hyphenated detection systems are discussed. For each of these groups, a brief description of the techniques, specific features, and concepts, as well as several examples, are described.Junta de AndalucÃa FQM-5974CEI-Biotic Granada CEI2013- MP-1
Parity (and time-reversal) anomaly in a semiconductor
The physics of a parity anomaly, potentially observable in a narrow-gap
semiconductor, is revisited. Fradkin, Dagotto, and Boyanovsky have suggested
that a Hall current of anomalous parity can be induced by a Peierls distortion
on a domain wall. I argue that a perturbation inducing the parity anomaly must
break the time reversal symmetry, which rules out the Peierls distortion as a
potential cause. I list all possible perturbations that can generate the
anomaly.Comment: 11 pages, 1 figure. Sign errors fixe
Transport behaviour of a Bose Einstein condensate in a bichromatic optical lattice
The Bloch and dipole oscillations of a Bose Einstein condensate (BEC) in an
optical superlattice is investigated. We show that the effective mass increases
in an optical superlattice, which leads to localization of the BEC, in
accordance with recent experimental observations [16]. In addition, we find
that the secondary optical lattice is a useful additional tool to manipulate
the dynamics of the atoms.Comment: Modified manuscrip
Photoemission and the Origin of High Temperature Superconductivity
The condensation energy can be shown to be a moment of the change in the
occupied part of the spectral function when going from the normal to the
superconducting state. As a consequence, there is a one to one correspondence
between the energy gain associated with forming the superconducting ground
state, and the dramatic changes seen in angle resolved photoemission spectra.
Some implications this observation has are offered.Comment: 4 pages, M2S conference proceeding
Chasing the identification of ASCA Galactic Objects (ChIcAGO): An X-ray survey of unidentified sources in the galactic plane. I : Source sample and initial results
We present the Chasing the Identification of ASCA Galactic Objects (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the Fx 10-13 to 10-11 erg cm -2 s-1 X-ray flux range. In ChIcAGO, the subarcsecond localization capabilities of Chandra have been combined with a detailed multiwavelength follow-up program, with the ultimate goal of classifying the >100 unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have been detected in these Chandra observations within 3′ of the original ASCA positions. We have identified infrared and optical counterparts to the majority of these sources, using both new observations and catalogs from existing Galactic plane surveys. X-ray and infrared population statistics for the X-ray point sources detected in the Chandra observations reveal that the primary populations of Galactic plane X-ray sources that emit in the Fx 10-13 to 10-11 erg cm -2 s-1 flux range are active stellar coronae, massive stars with strong stellar winds that are possibly in colliding wind binaries, X-ray binaries, and magnetars. There is also another primary population that is still unidentified but, on the basis of its X-ray and infrared properties, likely comprises partly Galactic sources and partly active galactic nuclei.Peer reviewedSubmitted Versio
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