25,477 research outputs found
A Dual Band Belt Antenna
This paper presents an antenna structure design using a standard belt for wearable applications. The antenna arouse from a body of research work on wearable metallic structures functioning as antennas for wireless on-body networks
Synthesis and Structure of the Bidimensional Zeolite ITQ-32 with Small and Large Pores
The authors thank to the Spanish CICYT for financial support (MAT2003-07945-C02-01, MAT2003-07769-C02-01, MAT2002-02808).Cantin Sanz, A.; Corma Canós, A.; Leiva, S.; Rey Garcia, F.; Rius, J.; Valencia Valencia, S. (2005). Synthesis and Structure of the Bidimensional Zeolite ITQ-32 with Small and Large Pores. Journal of the American Chemical Society. 127(33):11560-11561. https://doi.org/10.1021/ja053040hS11560115611273
Analysis of CMB maps with 2D wavelets
We consider the 2D wavelet transform with two scales to study sky maps of
temperature anisotropies in the cosmic microwave background radiation (CMB). We
apply this technique to simulated maps of small sky patches of size 12.8 \times
12.8 square degrees and 1.5' \times 1.5' pixels. The relation to the standard
approach, based on the cl's is established through the introduction of the
scalogram. We consider temperature fluctuations derived from standard, open and
flat-Lambda CDM models. We analyze CMB anisotropies maps plus uncorrelated
Gaussian noise (uniform and non-uniform) at idfferent S/N levels. We explore in
detail the denoising of such maps and compare the results with other techniques
already proposed in the literature. Wavelet methods provide a good
reconstruction of the image and power spectrum. Moreover, they are faster than
previously proposed methods.Comment: latex file 7 pages + 5 postscript files + 1 gif file; accepted for
publication in A&A
Influence of OH- concentration on the illitization of kaolinite at high pressure
The products of hydrothermal reactions of kaolinite at 300°C and 1000 bars were studied in KOH solutions covering an OH- concentration, [OH-], of 1M to 3.5M. XRD patterns indicated a notable influence of the [OH-] on the reaction. At [OH]≥3M, the only stable phase was muscovite/illite. The content of muscovite/illite was calculated from the analysis of the diagnostic 060 reflections of kaolinite and muscovite/illite. The results showed a linear dependence of kaolinite and muscovite/illite contents with [OH-]. 27Al MAS NMR spectroscopy revealed the formation of small nuclei of K-F zeolite at high [OH-]. Finally, modelling of the 29Si MAS NMR spectra indicated that the Si/Al ratio of the muscovite/illite formed was very close to that of muscovite, at least in the mineral formed at low [OH-]. In good agreement with the XRD data, the quantification of the reaction products by 29Si MAS NMR indicated a linear decrease of the kaolinite content with increasing OH- concentration.Dirección General de Investigación Científica y Técnica CTQ2007-63297Junta de Andalucía P06-FQM-0217
Redesign and cascade tests of a supercritical controlled diffusion stator blade-section
A supercritical stator blade section, previously tested in cascade, and characterized by a flat-roof-top suction surface Mach number distribution, has been redesigned and retested. At near design conditions, the losses and air turning were improved over the original blade by 50 percent and 7 percent respectively. The key element in the improved performance was a small blade reshaping. This produced a continuous flow acceleration over the first one-third chord of the suction surface which successfully prevented a premature laminar separation bubble. Several recently available inviscid analysis and one fully viscous (Navier-Stokes) analysis code were used in the redesign process. The validity of these codes was enhanced by the test results
Asymptotic solvers for ordinary differential equations with multiple frequencies
We construct asymptotic expansions for ordinary differential equations with highly oscillatory forcing terms, focusing on the case of multiple, non-commensurate frequencies. We derive an asymptotic expansion in inverse powers of the oscillatory parameter and use its truncation as an exceedingly effective means to discretize the differential equation in question. Numerical examples illustrate the effectiveness of the method
On It\^{o}'s formula for elliptic diffusion processes
Bardina and Jolis [Stochastic process. Appl. 69 (1997) 83--109] prove an
extension of It\^{o}'s formula for , where has a locally
square-integrable derivative in that satisfies a mild continuity condition
in and is a one-dimensional diffusion process such that the law of
has a density satisfying certain properties. This formula was expressed
using quadratic covariation. Following the ideas of Eisenbaum [Potential Anal.
13 (2000) 303--328] concerning Brownian motion, we show that one can re-express
this formula using integration over space and time with respect to local times
in place of quadratic covariation. We also show that when the function has
a locally integrable derivative in , we can avoid the mild continuity
condition in for the derivative of in .Comment: Published at http://dx.doi.org/10.3150/07-BEJ6049 in the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
Moment bounds for a class of fractional stochastic heat equations
We consider fractional stochastic heat equations of the form . Here denotes the noise term. Under suitable assumptions,
we show that the second moment of the solution grows exponentially with time.
In particular, this answers an open problem in \cite{CoKh}. Along the way, we
prove a number of other interesting properties which extend and complement
results in \cite{foonjose}, \cite{Khoshnevisan:2013aa} and
\cite{Khoshnevisan:2013ab}
Asymptotic normality for the counting process of weak records and \delta-records in discrete models
Let be a sequence of independent and identically distributed
random variables, taking non-negative integer values, and call a
-record if , where is an
integer constant. We use martingale arguments to show that the counting process
of -records among the first observations, suitably centered and
scaled, is asymptotically normally distributed for . In particular,
taking we obtain a central limit theorem for the number of weak
records.Comment: Published at http://dx.doi.org/10.3150/07-BEJ6027 in the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
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