99 research outputs found
Developing Model-Based Design Evaluation for Pipelined A/D Converters
This paper deals with a prospective approach of modeling, design evaluation and error determination applied to pipelined A/D converter architecture. In contrast with conventional ADC modeling algorithms targeted to extract the maximum ADC non-linearity error, the innovative approach presented allows to decompose magnitudes of individual error sources from a measured or simulated response of an ADC device. Design Evaluation methodology was successfully applied to Nyquist rate cyclic converters in our works [13]. Now, we extend its principles to pipelined architecture. This qualitative decomposition can significantly contribute to the ADC calibration procedure performed on the production line in term of integral and differential nonlinearity. This is backgrounded by the fact that the knowledge of ADC performance contributors provided by the proposed method helps to adjust the values of on-chip converter components so as to equalize (and possibly minimize) the total non-linearity error. In this paper, the design evaluation procedure is demonstrated on a system design example of pipelined A/D converter. Significant simulation results of each stage of the design evaluation process are given, starting from the INL performance extraction proceeded in a powerful Virtual Testing Environment implemented in Maple™ software and finishing by an error source simulation, modeling of pipelined ADC structure and determination of error source contribution, suitable for a generic process flow
Statistics of the dissipated energy in driven single-electron transitions
We analyze the distribution of heat generated in driven single-electron
transitions and discuss the related non-equilibrium work theorems. In the
adiabatic limit, the heat distribution is shown to become Gaussian, with the
heat noise that, in spite of thermal fluctuations, vanishes together with the
average dissipated energy. We show that the transitions satisfy Jarzynski
equality for arbitrary drive and calculate the probability of the negative heat
values. We also derive a general condition on the heat distribution that
generalizes the Bochkov-Kuzovlev equality and connects it to the Jarzynski
equality.Comment: 5 pages, 2 figure
Comparative Depictions of Acne Vulgaris in Movies and in Animated Television Cartoons
[EN] Acne vulgaris is a common chronic skin disease with the highest prevalence during the teenage years.
The depiction of acne in animated television cartoons tends to follow a common plot, with a major character
developing a single, large pimple. The comedone distresses the character and acquaintances may
belittle the character, but the lesion resolves and the character learns a valuable life lesson. The portrayal
of acne in films is much more varied than cartoons. Films typically use acne depictions to signal a negative
aspect about characters. The five cartoons and five films detailed in this paper contain a variety of
social and psychological responses to acne which demonstrate how such a common skin disorder can
carry considerable social stigma. Cartoons and films may actually cause more harm than good by reinforcing
negative cultural stereotypes about acne. [ES] lescencia.
La representación del acné en los dibujos animados de la televisión tiende a seguir un patrón
común con un personaje principal al que le aparece un único y enorme grano. El comedón angustia al
personaje y sus conocidos le menosprecian, pero la lesión se resuelve y el personaje aprende una valiosa
lección de la vida. La descripción del acné en la películas es mucho más variada que en la televisión.
Los filmes utilizan, normalmente, el recurso del acné para señalar un aspecto negativo de los personajes.
Las cinco series de dibujos y las cinco películas abordadas en este trabajo contienen una gran variedad
de respuestas sociales y psicológicas frente al acné que demuestran como un trastorno de la piel tan
común puede conllevar estigmas sociales considerables. Los dibujos animados y las películas pueden, de
hecho, causar más daño que beneficio al reforzar estereotipos culturales negativos sobre este problema
Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As
Magnetic linear dichroism and birefringence in (Ga,Mn)As epitaxial layers is
investigated by measuring the polarization plane rotation of reflected linearly
polarized light when magnetization lies in the plane of the sample. We report
on the spectral dependence of the rotation and ellipticity angles in a broad
energy range of 0.12-2.7 eV for a series of optimized samples covering a wide
range on Mn-dopings and Curie temperatures and find a clear blue shift of the
dominant peak at energy exceeding the host material band gap. These results are
discussed in the general context of the GaAs host band structure and also
within the framework of the k.p and mean-field kinetic-exchange model of the
(Ga,Mn)As band structure. We find a semi-quantitative agreement between
experiment and theory and discuss the role of disorder-induced non-direct
transitions on magneto-optical properties of (Ga,Mn)As.Comment: 18 page
Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering
A semi-inclusive measurement of charged hadron multiplicities in deep
inelastic muon scattering off an isoscalar target was performed using data
collected by the COMPASS Collaboration at CERN. The following kinematic domain
is covered by the data: photon virtuality (GeV/), invariant
mass of the hadronic system GeV/, Bjorken scaling variable in the
range , fraction of the virtual photon energy carried by the
hadron in the range , square of the hadron transverse momentum
with respect to the virtual photon direction in the range 0.02 (GeV/ (GeV/). The multiplicities are presented as a
function of in three-dimensional bins of , , and
compared to previous semi-inclusive measurements. We explore the
small- region, i.e. (GeV/), where
hadron transverse momenta are expected to arise from non-perturbative effects,
and also the domain of larger , where contributions from
higher-order perturbative QCD are expected to dominate. The multiplicities are
fitted using a single-exponential function at small to study
the dependence of the average transverse momentum on , and . The power-law behaviour of the
multiplicities at large is investigated using various
functional forms. The fits describe the data reasonably well over the full
measured range.Comment: 28 pages, 20 figure
Light isovector resonances in π-p →π-π-π+p at 190 GeV/c
We have performed the most comprehensive resonance-model fit of π-π-π+ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction π-+p→π-π-π++precoil with a 190 GeV/c pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, 0.5<2.5 GeV/c2, and simultaneously in 11 bins of the reduced four-momentum transfer squared, 0.1<1.0 (GeV/c)2, are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with JPC=0-+, 1++, 2++, 2-+, 4++, and spin-exotic 1-+ quantum numbers. The model contains the well-known resonances π(1800), a1(1260), a2(1320), π2(1670), π2(1880), and a4(2040). In addition, it includes the disputed π1(1600), the excited states a1(1640), a2(1700), and π2(2005), as well as the resonancelike a1(1420). We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 t′ bins. We extract the relative branching fractions of the ρ(770)π and f2(1270)π decays of a2(1320) and a4(2040), where the former one is measured for the first time. In a novel approach, we extract the t′ dependence of the intensity of the resonances and of their phases. The t′ dependence of the intensities of most resonances differs distinctly from the t′ dependence of the nonresonant components. For the first time, we determine the t′ dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances. We have performed extensive systematic studies on the model dependence and correlations of the measured physical parameters
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. They cover the kinematic domain View the MathML source in the photon virtuality, 0.0045 GeV/c2 in the invariant mass of the hadronic system. The results from the sum of the z -integrated K+ and K 12 multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit
Measurement of P T -weighted Sivers asymmetries in leptoproduction of hadrons
The transverse spin asymmetries measured in semi-inclusive leptoproduction of hadrons, when weighted
with the hadron transverse momentum PT , allow for the extraction of important transverse-momentumdependent distribution functions. In particular, the weighted Sivers asymmetries provide direct information
on the Sivers function, which is a leading-twist distribution that arises from a correlation between the transverse momentum of an unpolarised quark in a transversely polarised nucleon and the spin of the nucleon.
Using the high-statistics data collected by the COMPASS Collaboration in 2010 with a transversely polarised proton target, we have evaluated two types of PT -weighted Sivers asymmetries, which are both
proportional to the product of the first transverse moment of the Sivers function and of the fragmentation
function. The results are compared to the standard unweighted Sivers asymmetries and used to extract the
first transverse moments of the Sivers distributions for u and d quark
Triangle Singularity as the Origin of the a1(1420)
The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a(1)(1420), decaying to f(0)(980)(pi). With a mass too close to and a width smaller than the axial-vector ground state a(1)(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a(1) (1260) resonance into K* (-> K pi) (K) over bar and subsequent rescattering through a triangle singularity into the coupled f(0)(980)p channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the lightmeson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect
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