Search results for "Principle"

<title>Multiatom microlaser: a stable source of photons with subpoissonian statistics</title>

2000

We studied a multi-atom model of microlaser. As initial conditions we took diagonal density matrix of atoms in the basis of symmetrized collective states. Under diagnonal invariance taking a place for such initial conditions, we considered peculiarities of dynamics of the field reduced density matrix comparing it with the one-atom case. The field possesses subpoissonian distributions in a quasistationare, which are stable with respect to relaxation and number of atoms fluctuations in a packet. When one does not measure the atomic state on output of the cavity, it is possible to observe a macroscopic superposition of few such subpoissonian distributions. Simulating a measuring process of the…

La Méthode como hermenéutica musical Homenaje a Edgar Morin por su 100º cumpleaños

2021

The present work addresses the principles and properties of the complex thought formulated by the French thinker Edgar Morin and the way in which he was able me to articulate his conception of organizational complexity with one of the most important theories of musical analysis, which emerged at the beginning of the 20th century: the schenkerian analysis. It is a review and extension of a few pages of my doctoral thesis, which are intended to pay tribute to who has been, in addition to my teacher, Honorary President of Itamar since its first issue. His teachings and support has always been the engine for my quest for musical organization. On July 21, 2021, Morin celebrated his 100th birthda…

Oxygen evolution reaction on a N-doped Co0.5-terminated Co3O4 (001) surface

2020

The project AP05131211 “First principles investigation on catalytic properties of N-doped Co3O4.” was funded by the Ministry of Education and Science of the Republic of Kazakhstan. The work was partly supported by COST (European Cooperation in science and Technology) Action 18234 (YM and EK). The work of T. Inerbaev was performed under the state assignment of Sobolev Institute of Geology and Mineralogy Siberian Branch of the Russian Academy of Sciences. YM and EK thank Sun-to-Chem project of ERA Net.

Virtual Reality Applications for Higher Educations: A Market Analysis

2021

Infinitely many periodic solutions for a second-order nonautonomous system

2003

The existence of infinitely many solutions for a second-order nonautonoumous system was investigated. Some multiplicity results for problem (P) under very different assumptions on the potential G were established. It was shown that infinitely many solutions follow from a variational principle by B. Ricceri.

Dual-polarization-pump CW laser operation in Nd3+:LiNbO3 channel waveguides fabricated by reverse proton exchange

2008

Abstract In this work, continuous-wave laser action at 1084.5 nm at room temperature in LiNbO 3 :Nd 3+ channel waveguides, fabricated by reverse proton exchange (RPE), is reported. The sample was pumped at λ  = 808 nm in either σ or π-polarized configurations, TE- and TM-pumping schemes, being the laser emission π-polarized at all power levels. The laser characteristics, as function of the pumping scheme (TE or TM), have been obtained. In both cases, the laser emission was stable, without any reduction in the output power even under continuous pump operation at maximum power at room temperature, indicating high resistance to photorefractive damage.

A nonlocal problem arising from heat radiation on non-convex surfaces

1997

We consider both stationary and time-dependent heat equations for a non-convex body or a collection of disjoint conducting bodies with Stefan-Boltzmann radiation conditions on the surface. The main novelty of the resulting problem is the non-locality of the boundary condition due to self-illuminating radiation on the surface. Moreover, the problem is nonlinear and in the general case also non-coercive. We show that the non-local boundary value problem admits a maximum principle. Hence, we can prove the existence of a weak solution assuming the existence of upper and lower solutions. This result is then applied to prove existence under some hypotheses that guarantee the existence of sub- and…

FINITE ELEMENT APPROXIMATION OF NONLOCAL HEAT RADIATION PROBLEMS

1998

This paper focuses on finite element error analysis for problems involving both conductive and radiative heat transfers. The radiative heat exchange is modeled with a nonlinear and nonlocal term that also makes the problem non-monotone. The continuous problem has a maximum principle which suggests the use of inverse monotone discretizations. We also estimate the error due to the approximation of the boundary by showing continuous dependence on the geometric data for the continuous problem. The final result of this paper is a rigorous justification and error analysis for methods that use the so-called view factors for numerical modeling of the heat radiation.

Engaging with mathematics in the kindergarten. Orchestrating a fairy tale through questioning and use of tools

2013

ABSTRACTThe aim of this study is to analyse how a kindergarten teacher orchestrated a mathematical activity involving a fairy tale. Taking a sociocultural perspective on learning and development, naturally occurring talk-in-interaction has been analysed in order to scrutinise the subtleties of the orchestration. The fairy tale Goldilocks and the Three Bears was used both as context for the activity, but also as a means through which mathematical concepts were engaged with. The analysis shows that the orchestration bears characteristics of questioning and use of tools such as voice, facial expressions, and concrete materials. The orchestration is also characterised by sincere planning in adv…

Visual information flow in Wilson-Cowan networks.

2020

In this paper, we study the communication efficiency of a psychophysically tuned cascade of Wilson-Cowan and divisive normalization layers that simulate the retina-V1 pathway. This is the first analysis of Wilson-Cowan networks in terms of multivariate total correlation. The parameters of the cortical model have been derived through the relation between the steady state of the Wilson-Cowan model and the divisive normalization model. The communication efficiency has been analyzed in two ways: First, we provide an analytical expression for the reduction of the total correlation among the responses of a V1-like population after the application of the Wilson-Cowan interaction. Second, we empiri…