bluuebunny/crossref_metadata_2025_split huggingface dataset:
MIXING AND PHASE SEPARATION IN LIQUID CRYSTAL/MATRIX SYSTEMS
Authors: SMITH GEORGE W. 
Published: November 2004

We review mixing and phase separation (demixing) in mixtures of low molecular weight liquid crystals (LCs) and organic matrices, with emphasis on aspects relevant to the formation of polymer-dispersed liquid crystal films. These films, which contain a myriad of micron-sized LC droplets, are of interest because of their electro-optic properties. Film formation is simple: A liquid crystal and a liquid polymer precursor are initially mixed to form a single phase. Subsequently the polymer is hardened, and LC microdroplets phase-separate from the matrix. Although matrix hardening can be achieved in several ways, this review focuses on curing, during which cross-linking reactions lead to an increased matrix molecular weight. Topics discussed include: phase behavior of the binary system before, during, and after cure and LC/matrix solubilities. The Flory-Huggins model for phase separation (as modified by several workers) has provided a theoretical basis for the studies. Principal experimental tools have been calorimetry and light scattering. Uncured LC/matrix binaries possess phase diagrams with an upper critical solution temperature. Such systems, when heated through the mixing temperature, exhibit a decrease in specific heat, the (negative) excess specific heat of mixing, ∆ C mix . A plot of ∆ C mix vs. LC concentration exhibits a minimum, from which we can estimate LC and uncured-matrix solubilities. Matrix cure plays a major role in the phase separation process: In partially-cured samples, ∆ C mix transitions persist until cure is nearly complete, at which time a fraction of the LC is permanently phase-separated, with the rest remaining dissolved in the matrix. The kinetics of phase separation can be determined by calorimetry or light scattering. Cure rates have been shown to control LC microdroplet size, with fast cures leading to small droplets. Calorimetry of the fully cured system also allows us to determine the solubility of liquid crystal in the polymer matrix, as well as the fraction of phase-separated LC. An approximation based on the lever rule and the Flory-Huggins spinodal curve provides an upper bound for the solubilities and also describes their temperature dependence.
SOME STUDIES ON ARITHMETICAL CHAOS IN CLASSICAL AND QUANTUM MECHANICS
Authors: BOLTE JENS 
Published: November 2004

Several aspects of classical and quantum mechanics applied to a class of strongly chaotic systems are studied. The latter consists of single particles moving without external forces on surfaces of constant negative Gaussian curvature whose corresponding fundamental groups are supplied with an arithmetic structure. It is shown that the arithmetical features of the considered systems lead to exceptional properties of the corresponding spectra of lengths of closed geodesics (periodic orbits). The most significant one is an exponential growth of degeneracies in these geodesic length spectra. Furthermore, the arithmetical systems are distinguished by a structure that appears as a generalization of geometric symmetries. These pseudosymmetries occur in the quantization of the classical arithmetic systems as Hecke operators, which form an infinite algebra of self-adjoint operators commuting with the Hamiltonian. The statistical properties of quantum energies in the arithmetical systems have previously been identified as exceptional. They do not fit into the general scheme of random matrix theory. It is shown with the help of a simplified model for the spectral form factor how the spectral statistics in arithmetical quantum chaos can be understood by the properties of the corresponding classical geodesic length spectra. A decisive role is played by the exponentially increasing multiplicities of lengths. The model developed for the level spacings distribution and for the number variance is compared to the corresponding quantities obtained from quantum energies for a specific arithmetical system. Finally, the convergence properties of a representation for the Selberg zeta function as a Dirichlet series are studied. It turns out that the exceptional classical and quantum mechanical properties shared by the arithmetical systems prohibit a convergence of this important function in the physically interesting domain.
THE INFLUENCE OF Pb, Ni AND V DOPING ON THE CHARACTERISTICS OF HIGH-TcBi-Si-Ca-Cu-O SUPERCONDUCTORS
Authors: KHAN M.N. , MEMON A. , AL-DALLAL S. , AL-OTHMAN M. , ZEIN M. , ALNASER W. 
Published: November 2004

We report on the studies of ac susceptibility, ultrasonic attenuation, superconductivity and some calorimetric measurements on Pb -doped for Bi -site as well as Ni and V substitution for Cu in Bi-Sr-Ca-Cu-O superconductors. It was confirmed that the Bi(Pb)-based glass ceramics (i.e. crystallized glasses) exhibit superconductivity with T c above 105 K higher than Bi(Ni) with Tc 68 K and Bi(V) -based glasses with T c 40K. X-ray diffraction analysis revealed that the structure of these materials is Bi -2223 type with a=4.067 Å and C=30.768 Å. It was found from the temperature dependence of ac complex susceptibility that the coupling nature at grain boundaries of superconducting crystals in the samples obtained was weak, and was improved by increasing the annealing time. Data are discussed for varying T c of different substituents. Our results on the ultrasonic attenuation revealed a series of relaxation peaks with low activation enthalpies which indicate that electronic defects may be the cause for the relaxation processes.
NEAR-COLLISIONS IN A COULOMB SYSTEM: NUMERICAL SIMULATIONS — A PRELUDE TO HYBRID FUSION
Authors: MENDES R. VILELA 
Published: November 2004

In the microcanonical phase space of a classical Coulomb system with positive (D) and negative (e) particles, low-energy near-collisions of two positive particles are dominated by (DeD) configurations. Computed from the area of the energy hypersurface where these events take place, the probability for (DeD) near-collisions is many orders of magnitude above the probability for tunneling through the Coulomb barrier in a (DeD)+ bound state, when e is a light particle. If the Coulomb system is embedded in a metallic lattice, access to the near-collision regions in the phase space is hindered by the regularity of the lattice. One should then expect, at most, intermittent and irreproducible behavior associated to mechanisms like Arnold’s diffusion. Mechanisms to restore ergodicity are proposed. Numerical simulations are performed on a three-body system to compare the observed rate of near-collisions in actual orbits (with random initial conditions) with the phase-space estimates. It is found that local conservation of angular momentum causes large deviations from the phase-space estimates.
RANGE ESTIMATION FROM CAMERA BLUR BY REGULARIZED ADAPTIVE IDENTIFICATION
Authors: HOLEVA LEE F. 
Published: November 2004

One of the fundamental problems of machine vision is the estimation of object depth from perceived images. This paper describes both an apparatus and the corresponding algorithms for the passive extraction of object depth. Here passive extraction implies the processing of images acquired using only the existing illumination, in this case roughly uniform white light. Depth from defocused algorithms are extremely sensitive to image variations. Regularization, the application of a priori constraints, is employed to improve the accuracy of the range measurements. When the camera’s point spread function is shift invariant, an adaptive algorithm is developed in the frequency domain. The constraints imposed upon the solution power spectrum vector vary temporally. When the camera’s point spread function is shift varying, an adaptive algorithm is developed in the spatial domain. The constraints imposed upon the solution point spread vector vary spatially. Data is acquired from line scan cameras. Only a single range measurement or a single depth profile is extracted. By relying upon the motion of the observed object on a conveyor belt, a complete range image may be generated.
CHUA’S CIRCUIT: AN OVERVIEW TEN YEARS LATER
Authors: CHUA LEON O. 
Published: November 2004

More than 200 papers, two special issues (Journal of Circuits, Systems, and Computers, March, June, 1993, and IEEE Trans. on Circuits and Systems, vol. 40, no. 10, October, 1993), an International Workshop on Chua’s Circuit: chaotic phenomena and applica tions at NOLTA’93, and a book (edited by R.N. Madan, World Scientific, 1993) on Chua’s circuit have been published since its inception a decade ago. This review paper attempts to present an overview of these timely publications, almost all within the last six months, and to identify four milestones of this very active research area. An important milestone is the recent fabrication of a monolithic Chua’s circuit. The robustness of this IC chip demonstrates that an array of Chua’s circuits can also be fabricated into a monolithic chip, thereby opening the floodgate to many unconventional applications in information technology, synergetics, and even music. The second milestone is the recent global unfolding of Chua’s circuit, obtained by adding a linear resistor in series with the inductor to obtain a canonical Chua’s circuit— now generally referred to as Chua’s oscillator. This circuit is most significant because it is structurally the simplest (it contains only 6 circuit elements) but dynamically the most complex among all nonlinear circuits and systems described by a 21-parameter family of continuous odd-symmetric piecewise-linear vector fields. The third milestone is the recent discovery of several important new phenomena in Chua’s circuits, e.g., stochastic resonance, chaos-chaos type intermittency, 1/f noise spectrum, etc. These new phenomena could have far-reaching theoretical and practical significance. The fourth milestone is the theoretical and experimental demonstration that Chua’s circuit can be easily controlled from a chaotic regime to a prescribed periodic or constant orbit, or it can be synchronized with 2 or more identical Chua’s circuits, operating in an oscillatory, or a chaotic regime. These recent breakthroughs have ushered in a new era where chaos is deliberately created and exploited for unconventional applications, e.g. secure communication.
Z-θ MOTION ACTUATOR WITH INTERIOR PERMANENT MAGNET MOVER
Authors: SANADA MASAYUKI , MORIMOTO SHIGEO , TAKEDA YOJI 
Published: November 2004

The linear pulse motor (LPM) can operate in an open-loop control mode similar to a rotary stepper motor, and it has large thrust in small input power and volume comparing with other linear motors. We proposed a new cylindrical linear pulse motor with an interior permanent magnet mover (IPMM-LPM), which has no thrust imbalance theoretically. The IPMM-LPM has the same mover cross section in comparison with the permanent magnet synchronous motor. Therefore, by only making an addition of an armature winding for the synchronous motor to the IPMM-LPM, the IPMM-LPM has an ability of a rotary motion as well as linear motion. In this paper, the new Z-θ motion actuator, which not only has the ability of linear motion but also rotary motion, is proposed and basic characteristics are examined in detail based on calculated and experimental results. The proposed Z-θ motion actuator is useful for machine tools such as a lathe and so forth.
ELLIPTIC NON-BIRKHOFF PERIODIC ORBITS IN THE TWIST MAPS
Authors: OLVERA ARTURO , SIMÓ CARLES 
Published: November 2004

We consider a perturbed twist map when the perturbation is big enough to destroy the invariant rotational curve (IRC) with a given irrational rotation number. Then an invariant Cantorian set appears. From another point of view, the destruction of the IRC is associated with the appearance of heteroclinic connections between hyperbolic periodic points. Furthermore the destruction of the IRC is also associated with the existence of non-Birkhoff orbits. In this paper we relate the different approaches. In order to explain the creation of non-Birkhoff orbits, we provide qualitative and quantitative models. We show the existence of elliptic non-Birkhoff periodic orbits for an open set of values of the perturbative parameter. The bifurcations giving rise to the elliptic non-Birkhoff orbits and other related bifurcations are analysed. In the last section, we show a celestial mechanics example displaying the described behavior.
DYNAMICAL INTEGRATION
Authors: BROWN RAY , CHUA LEON O. 
Published: November 2004

In this letter we show how to use a new form of integration, called dynamical integration, that utilizes the dynamics of a system defined by an ODE to construct a map that is in effect a one-step integrator. This method contrasts sharply with classical numerical methods that utilize polynomial or rational function approximations to construct integrators. The advantages of this integrator is that it uses only one step while preserving important dynamical properties of the solution of the ODE: First, if the ODE is conservative, then the one-step integrator is measure preserving. This is significant for a system having a highly nonlinear component. Second, the one-step integrator is actually a one-parameter family of one-step maps and is derived from a continuous transformation group as is the set of solutions of the ODE. If each element of the continuous transformation group of the ODE is topologically conjugate to its inverse, then so is each member of the one-parameter family of one-step integrators. If the solutions of the ODE are elliptic, then for sufficiently small values of the parameter, the one-step integrator is also elliptic. In the limit as the parameter of the one-step family of maps goes to zero, the one-step integrator satisfies the ODE exactly. Further, it can be experimentally verified that if the ODE is chaotic, then so is the one-step integrator. In effect, the one-step integrator retains the dynamical characteristics of the solutions of the ODE, even with relatively large step sizes, while in the limit as the parameter goes to zero, it solves the ODE exactly. We illustrate the dynamical, in contrast to numerical, accuracy of this integrator with two distinctly different examples: First we use it to integrate the unforced Van der Pol equation for large ∊, ∊≥10 which corresponds to an almost continuous square-wave solution. Second, we use it to obtain the Poincaré map for two different versions of the periodically forced Duffing equation for parameter values where the solutions are chaotic. The dynamical accuracy of the integrator is illustrated by the reproduction of well-known strange attractors. The production of these attractors is eleven times longer when using a conventional fourth-order predictor-corrector method. The theory presented here extends to higher dimensions and will be discussed in detail in a forthcoming paper. However, we caution that the theory we present here is not intended as a line of research in numerical methods for ODEs.
THE BASIN OF ATTRACTION OF A SPIN-ORBIT RESONANCE
Authors: CELLETTI ALESSANDRA , FALCOLINI CORRADO , TEDESCHINI-LALLI LAURA 
Published: November 2004

In this paper we investigate the different behaviors of some satellites, subject to a spin-orbit interaction. In particular we compute, in the space of initial data, the basin of attraction of the 3:2 resonance for the Mercury–Sun and Moon–Earth coupling systems. The results are obtained either by direct integration of the equations of motion or by a numerical implementation of the "straddle" technique to draw the boundary of the basin.
A TEST FOR STATIONARITY: FINDING PARTS IN TIME SERIES APT FOR CORRELATION DIMENSION ESTIMATES
Authors: ISLIKER HEINZ , KURTHS JÜRGEN 
Published: November 2004

We propose a method to identify stationary phases in time series. Stationarity is a necessary condition for many concepts in dynamical systems theory, e.g. deterministic chaos. Therefore, testing for stationarity should necessarily be the first step in any data analysis. Above all, this testing is highly important whenever one deals with systems for which stationarity is not guaranteed by the data acquisition procedure: if only short and unique time series are accessible and if the experimental situation is not or only restrictedly controllable, as for instance in astronomy, economy, or medicine. The proposed stationarity test is easily workable and easy to implement in the form of a systematically searching loop. It singles out the parts of a time series which are a reasonable input to a dimension estimate algorithm. Thereby, it can ascertain finite correlation dimensions which are not indicative of deterministic behavior; this kind of dimensions can occur in stochastic processes which are nonstationary, e.g. self-affine.
A KNOWLEDGE-BASED FRAMEWORK OF OBJECT-ORIENTED SOFTWARE DEVELOPMENT ENVIRONMENTS
Authors: SOURROUILLE JEAN LOUIS 
Published: November 2004

Software development can be seen as a formalization process which, from informal data (problem), leads to a fully formal representation (solution) by successive enrichments and transformations. This paper presents a representation formalism (KLSDE: Knowledge-based representation Language for Software Development Environments) which supports the iterative and evolutionary features of this process. From syntactic and semantic rules described in the domain model and the software process model, the representation is gradually bound by stronger and stronger constraints, according to the degree of formalization. Based on object concepts, KLSDE offers both expressive power as well as simplicity and readability. The power, which stems from knowledge representation techniques, is necessary to build various models such as the software process development, the domain or the solution. Readability and simplicity are required so that the language addresses communication needs. For readability, the language is constructed on current metaphors and concepts. It includes a graphic representation and many structuring mechanisms. Finally, KLSDE is at the center of a development environment. It is parameterized by the user methodology and fulfills the needs for the whole life-cycle.
THE CLASSICAL LIMIT OF A SELF-CONSISTENT QUANTUM-VLASOV EQUATION IN 3D
Authors: MARKOWICH PETER A. , MAUSER NORBERT J. 
Published: November 2004

Under natural assumptions on the initial density matrix of a mixed quantum state (Hermitian, non-negative definite, uniformly bounded trace, Hilbert-Schmidt norm and kinetic energy) we prove that accumulation points (as the scaled Planck constant tends to zero) of solutions of a corresponding slightly regularized Wigner-Poisson system are distributional solutions of the classical Vlasov-Poisson system. The result holds for the gravitational and repulsive cases. Also, for every phase-space density in [Formula: see text] (with bounded kinetic energy) we prepare a sequence of density matrices satisfying the above assumptions, such that the given density is the limit of the Wigner transforms of these density matrices.
THE SWITCHING BEHAVIOR OF A ONE-DIMENSIONAL PN-DIODE IN LOW INJECTION
Authors: SCHMEISER C. , UNTERREITER A. , WEISS R. 
Published: November 2004

The switching of a semiconductor PN-diode from forward to reverse bias is studied. A mathematical model is derived from a one-dimensional version of the standard drift diffusion equations by formal asymptotics. The simplifying assumptions amount to vanishing space charge, low injection, “long” devices and strongly asymmetric doping. The model is equivalent to a nonlinear Volterra integral equation of the second kind for the current through the device. Existence, uniqueness, analyticity and monotonicity of the solution are proved. In typical situations the integral equation is singularly perturbed. A rigorous perturbation analysis shows that the model is able to reproduce the experimentally observed switching behavior.
THE FREE STREAMING OPERATOR WITH MAXWELL TYPE BOUNDARY CONDITIONS IN ASYMMETRIC SOBOLEV SPACES
Authors: TOTARO SILVIA 
Published: November 2004

Some properties of the free streaming operator T with Maxwell type boundary conditions are studied in this paper. The domain D(T) is assumed to be contained in a suitable asymmetric Sobolev space. The norm of the element f is defined in such a space by the sum [Formula: see text], where ‖ ‖1 is the usual L1 norm and c is a constant. It is proved that T generates a contraction semigroup, which preserves positivity.
A THEORY REVISION APPROACH FOR CONCEPT LEARNING
Authors: CHEN PO-CHI , YU YONG-NENG , HWANG SHU-YUEN 
Published: November 2004

Concept learning from examples in first-order languages has been widely studied recently. Specifically, many systems that integrate inductive learning and explanation-based learning have been proposed. However, concept learning is only a subproblem of the problem of knowledge base (which is referred to as a theory in first-order logic) revision. This is mainly because concept learning methods utilize background knowledge without regard to whether the knowledge is perfect or imperfect, while a knowledge base revision system should revise the knowledge base to be consistent with all environmental changes. This paper presents a real theory revision method that guarantees the revised theory to be correct on all given examples. As a consequence, the problem of concept learning is also solved through the proposed method. The proposed method is a two-phase approach. In the first phase, the input theory is generalized to cover all positive examples. Theoretically, this can be done by existing concept learning systems. The second phase then specializes the theory to exclude negative examples. The specialization must not cause excessive exclusion of covered positive examples. The paper focuses on designing such a specialization algorithm. Experimental results show that the proposed algorithm can mitigate the over-specialization problem.
A LOGICAL DESCRIPTION OF THE EVOLUTION OF FEEDBACK LOOP SYSTEMS AND ITS APPLICATION TO RHABDOVIRUS INFECTION
Authors: MARTINET-EDELIST CLAIRE 
Published: November 2004

The molecular biology of viruses can be effectively described by kinetic logic, even in its so-called “naïve” version, since feedback loops are implicated in all viral cycles and viral proteins generally display several functions. A general method for the evolution of systems involving feedback loops using this modelling is presented. It can be summarized as follows: (i) description of the system through boolean equations, (ii) identification of the steady states (is there a good agreement between the observations and the logical description?), (iii) experimental determination of several parameters, (iv) computer simulation of viral cycles, (v) predictions and their relation to the biological facts. This survey of oscillation between experimentation and logical description was applied to the study of rhabdovirus cycles and allowed us to describe some aspects of their gene expression.