3,282 research outputs found
Recent results on GaAs detectors - 137
The present understanding of the charge collection in GaAs detectors with
respect to the materials used and its processing are discussed. The radiation
induced degradation of the charge collection efficiency and the leakage current
of the detectors are summarised. The status of strip and pixel detectors for
the ATLAS experiment are reported along with the latest results from GaAs X-ray
detectors for non-high energy physics applications.Comment: 7 pages. 4 postscript figures + 1 postscript preprint logo + 1 LaTeX
file + 1 style file. Also available at
http://ppewww.ph.gla.ac.uk/preprints/97/05
Connection between dynamics and thermodynamics of liquids on the melting line
The dynamics of a large number of liquids and polymers exhibit scaling
properties characteristic of a simple repulsive inverse power law (IPL)
potential, most notably the superpositioning of relaxation data as a function
of the variable TV{\gamma}, where T is temperature, V the specific volume, and
{\gamma} a material constant. A related scaling law, TmVm{\Gamma}, with the
same exponent {\Gamma}={\gamma}, links the melting temperature Tm and volume Vm
of the model IPL liquid; liquid dynamics is then invariant at the melting
point. Motivated by a similar invariance of dynamics experimentally observed at
transitions of liquid crystals, we determine dynamic and melting point scaling
exponents {\gamma} and {\Gamma} for a large number of non-associating liquids.
Rigid, spherical molecules containing no polar bonds have {\Gamma}={\gamma};
consequently, the reduced relaxation time, viscosity and diffusion coefficient
are each constant along the melting line. For other liquids {\gamma}>{\Gamma}
always; i.e., the dynamics is more sensitive to volume than is the melting
point, and for these liquids the dynamics at the melting point slows down with
increasing Tm (that is, increasing pressure).Comment: 20 pages, 8 figures, 1 tabl
Nanoscale ear drum: Graphene based nanoscale sensors
The difficulty in determining the mass of a sample increases as its size
diminishes. At the nanoscale, there are no direct methods for resolving the
mass of single molecules or nanoparticles and so more sophisticated approaches
based on electromechanical phenomena are required. More importantly, one
demands that such nanoelectromechanical techniques could provide not only
information about the mass of the target molecules but also about their
geometrical properties. In this sense, we report a theoretical study that
illustrates in detail how graphene membranes can operate as
nanoelectromechanical mass-sensor devices. Wide graphene sheets were exposed to
different types and amounts of molecules and molecular dynamic simulations were
employed to treat these doping processes statistically. We demonstrate that the
mass variation effect and information about the graphene-molecule interactions
can be inferred through dynamical response functions. Our results confirm the
potential use of graphene as mass detector devices with remarkable precision in
estimating variations in mass at molecular scale and other physical properties
of the dopants
Anomalous Crossing Frequency in Odd Proton Nuclei
A generic explanation for the recently observed anomalous crossing
frequencies in odd proton rare earth nuclei is given. As an example, the proton
band in Ta is discussed in detail by using the
angular momentum projection theory. It is shown that the quadrupole pairing
interaction is decisive in delaying the crossing point and the changes in
crossing frequency along the isotope chain are due to the different neutron
shell fillings
O direito ao esquecimento como limitação à liberdade de expressão / Right to oblivion as a limitation on freedom of expression
O tema Direito ao esquecimento como limitação à liberdade de expressão em face do direito de intimidade do respeito permitiu-nos investigar sobre a dignidade da pessoa humana tutelada pelos princípios constitucionais. A vida privada da pessoa, sua privacidade e intimidade são asseguradas pela Carta Magna. Os crimes de invasão da privacidade e da intimidade são puníveis e passíveis de indenização por danos morais e materiais. O problema de pesquisa norteador desse estudo foi este: Quais as limitações à exposição da imagem da pessoa pública? O objetivo geral é refletir sobre o direito ao esquecimento como limitação à liberdade de expressão. O Enunciado 531 inserido no ordenamento jurídico por meio da VI Jornada de Direito Civil apregoa que “A tutela da dignidade da pessoa humana na sociedade da informação inclui o direito ao esquecimento”. A liberdade de expressão não contradiz os princípios constitucionais, pelo contrário, a ponderação entre a ética do jornalismo e a dignidade da pessoa humana permitem maior segurança aos direitos de imagem da pessoa pública. A falta de legislação mais específica de invasão da intimidade e da privacidade da pessoa leva os agentes da justiça a se pautarem em princípios mais gerais como os regulamentados pela Declaração Universal dos Direitos Humanos, seguida pelo texto da Constituição Federal que dá garantias aos princípios fundamentais da Dignidade Humana em seu artigo 5º
Existence results for a contact problem with varying friction coefficient and nonlinear forces
We consider the rate-independent problem of a particle moving in a three - dimensional half space subject to a time-dependent nonlinear restoring force having a convex potential and to Coulomb friction along the flat boundary of the half space, where the friction coefficient may vary along the boundary. Our existence result allows for solutions that may switch arbitrarily often between unconstrained motion in the interior and contact where the solutions may switch between sticking and frictional sliding. However, our existence result is local and guarantees continuous solutions only as long as the convexity of the potential is strong enough to compensate the variation of the friction coefficient times the contact pressure. By simple examples we show that our sufficient conditions are also necessary. Our method is based on the energetic formulation of rate-independent systems as developed by Mielke and co-workers. We generalize the time-incremental minimization procedure of Mielke and Rossi for the present situation of a non-associative flow rule
Peripheral polyneuropathy after bariatric surgery : independent association with high-density lipoprotein (HDL) cholesterol in a cohort study
Dynamics of Phase Transitions Induced by a Heat Bath
We study the non-equilibrium dynamics of a symmetry restoring phase
transition in a scalar field theory, the ``system'', linearly coupled to
another scalar field taken as a ``heat bath''. The ``system'' is initially in
an ordered low temperature phase, and the heat bath is at a temperature close
to the critical temperature for the system. We estimate the time at which the
phase transition to the disordered (symmetric) phase takes place. We derive,
and integrate the one-loop effective equations of motion for the order
parameter that include the effects of the heat bath. A semiclassical Langevin
equation is derived and it is found that it contains a non-dissipative,
non-Markovian kernel, the noise term is colored and correlated on time scales
determined by the temperature of the heat bath. The range of validity of the
Langevin equation and a consistent procedure to incorporate corrections are
discussed.Comment: 26 pages, 3 figures (not included) Late
Evaluating inputs for organic farming – a new system. Proposals of the ORGANIC INPUTS EVALUATION project
This volume contains proposals for criteria for evaluation of plant protection products, fertilisers and soil conditioners1 to be used in organic agriculture. These ideas were developed in the course of the European Union (EU) Concerted Action project ‘ORGANIC INPUTS EVALUATION’ (QLK5-CT-2002-02565). For more information on this project see the end of this volume or visit the project website www.organicinputs.org. The documents in this volume are proposals elaborated by the project consortium and external experts. They were discussed with a broader audience at a public conference held in Brussels on October 13, 2005, and have been amended accordingly.
Our proposals also include a “criteria matrix”, which is in Microsoft Excel format, and therefore stands as a separate file. The criteria matrix is discussed in section 5, but we strongly recommend that you consult the original document. To illustrate the use of the matrix, we have further prepared two case studies, which are also separate Excel files. All of these files are contained on the CD, and can also be downloaded from the project website.
Currently, Regulation 2092/91 is under revision. We hope that our ideas can be incorporated into the regulation during this revision! In addition, we strongly encourage national institutions to make use of our proposals at the national level
Dynamic biospeckle analysis, a new tool for the fast screening of plant nematicide selectivity
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