Miracle-dz/UniFAR-FTUs huggingface dataset:
From Local to Global Triangularization

Abstract It is shown that a semigroup of Shatten p -class operators is simultaneously triangularizable if each pair of operators in the semigroup is triangularizable. Several sufficient conditions for triangularizability of semigroups are obtained as corollaries. A “block triangularization” theorem for algebras of compact operators is established, consequences of which include a number of necessary and sufficient conditions for triangularization of such algebras.
Cumulative second-harmonic generation accompanying nonlinear shear horizontal mode propagation in a solid plate

In this article cumulative second-harmonic generation accompanying nonlinear shear horizontal (SH) mode propagation in a solid plate has been studied. Generally, the amplitude of the driven second harmonic arising from the self-interaction of the shear wave is independent of propagation distance. However, for SH mode propagation consisting of two shear waves, the cross interaction between two shear waves may cause the cumulative effect of the driven second harmonic once the phase velocity of SH mode propagation equals the longitudinal velocity of the plate material. In practical issues, one is especially interested in the case in which the second-harmonic amplitude is dependent of propagation distance. With appropriate boundary and initial conditions of excitation, the process of cumulative second-harmonic generation is clearly shown, and the analytical expression of the cumulative second harmonic is determined. Although the plane second harmonic without the cumulative effect cannot be determined in the p.
Model Experiment, Numerical Simulation and Theoretical Analysis on the Characteristics of a Viscous Micropump Using a Cylindrical Rotor in a Rectangular Duct

The present paper describes the characteristics of a viscous micropump with a cylindrical rotor in a rectangular duct. In the model experiment, the low Reynolds number flow is realized by using glycerin as a working fluid for a centimeter-scale (non-micrometer-scale) pump model. In the numerical simulation, the commercial code, STAR-CD, is used. Qualitative and quantitative agreements between the experimental and numerical results are obtained with respect to the flow fields and the pump characteristics, i.e. pressure performance and pump efficiency. The experimental and numerical results show that there exist three recirculations near the rotor, rotating in the opposite direction of the rotor. They also show that pressure performance represents a straight line with a negative slope. In the theoretical analysis, the Buckingham’s pi theorem is applied with the low Reynolds number approximation. As a result, two new dimensionless parameters are obtained for flow rate and pressure rise. By using the two new dimensionless parameters, the unified treatment of pressure performance is possible, independent of the Reynolds number. The low Reynolds number approximation is valid when the Reynolds number is smaller than 100.
N-compact spaces as limits of inverse systems of discrete spaces

Abstract Let N denote the discrete space of all natural numbers. A space X is N-compact if it is homeomorphic with some closed subspace of a product of copies of N. In this paper, N-compact spaces are characterized as homeomorphs of inverse limit space of inverse systems of copies of subsets of N. Also, it is shown that a space X is N-compact if and only if the space (X) of all non-empty compact subsets of X with the finite topology is N-compact.
ON AN EIGENVALUE PROBLEM FOR AN ANISOTROPIC ELLIPTIC EQUATION INVOLVING VARIABLE EXPONENTS

Abstract We study the eigenvalue problem $\(-\sum_{i=1}^N\di\partial_{x_i}(|\di\partial_{x_i}u |^{p_i(x)-2}\di\partial_{x_i}u)$ = λ|u|q(x)−2u in Ω, u = 0 on ∂Ω, where Ω is a bounded domain in ℝN with smooth boundary ∂Ω, λ is a positive real number, and p1,⋅ ⋅ ⋅, pN, q are continuous functions satisfying the following conditions: 2 ≤ pi(x) < N, 1 < q(x) for all x ∈ Ω, i ∈ {1,. ,N}; there exist j, k ∈ {1,. ,N}, j ≠ k, such that pj ≡ q in Ω, q is independent of xj and maxΩq < minΩpk. The main result of this paper establishes the existence of two positive constants λ0 and λ1 with λ0 ≤ λ1 such that every λ ∈(λ1, ∞) is an eigenvalue, while no λ ∈ (0, λ0) can be an eigenvalue of the above problem.
The Intelligibility of Interrupted Speech

The paper concerns the effect of intermittent interruptions of the speech wave upon intelligibility as measured by word articulation tests. The principal experimental variables are: the interruption rate (the number of on‐off cycles per second) and the speech‐time fraction (the fraction of the time that the communication circuit is turned on). When the interruption rate is very low (on and off once in ten seconds), the percentage of the words heard correctly is, of course, equal approximately to the product of (a) the percentage understood in the absence of interruptions and (b) the speech‐time fraction. At the other extreme, when the interruption rate is very high (on and off 5000 times a second), intelligibility is essentially unimpaired regardless of the speech‐time fraction. In the intermediate range, each curve of the family relating intelligibility to interruption rate for various speech‐time fractions rises to a maximum at about 15 interruptions per second, then falls to a minimum in the neighborhood of 300 interruptions per second. With a sound‐time fraction of 0.50 and 15 interruptions per second, the listeners hear almost all of the words despite the fact that the speech is, and sounds, intermittent. A curious effect is produced when, with the same speech‐time fraction and the same interruption rate, the speechless intervals are filled with white noise. No longer does the speech sound intermittent; instead, it is as though the speech were the scene behind a picket fence, viewed by a moving observer. The speech sounds continuous, and the words are understood just as well as they were before the noise was introduced. In the experiments just described, the interruptions occurred at regular intervals and the speech was turned on and off abruptly. Other experiments were conducted with iterruptions at irregular intervals and with gradual transition from “on” to “off” and vice versa. The disturbance produced by irregular interruption sounded very much like static and was therefore readily distinguishable from the effect produced by regular interruption. (At high rates, the latter has a tonal quality.) The intelligibility scores, however, were approximately the same with irregular as with regular interruptions. Changing from abrupt to gradual modulation (holding constant the speech‐time fraction as measured at a level corresponding to one‐half the peak speech amplitude) improved both the quality and the intelligibility of the interrupted speech.
Synchronous and Asynchronous Integrations in an Ocean General Circulation Model

Abstract A basinwide ocean general circulation model of the North Pacific is used to study the difference in distributions of tracers between asynchronous and synchronous integrations. An integration in which equal time steps and no depth acceleration are applied is called a synchronous integration. On the contrary, the integration is called asynchronous integration or acceleration. The acceleration can be divided into tracer acceleration and depth acceleration. Only the tracer acceleration is examined in this study. The values of 48, 24, 12, 6, 3, and 1 for the ratio (α) of tracer time step to momentum time step are used in the model. Results show that a 15-yr integration adjustment is necessary for tracers to reach a new state at which there is a 1% difference from a final state upon a switch to a smaller tracer time step from an equilibrium state. The too large ratio of 48 generally produces an unacceptable departure from synchronous integration. If a difference of about 3% is allowed, the ratio of abo.
Development of time resolved x-ray spectroscopy in high intensity laser-plasma interactions

This article discusses the design of a novel time resolved von Hamos Bragg spectrometer to provide spectra in the region around the titanium K-α and He-α lines. The instrument consists of a highly oriented pyrolitic graphite mosaic crystal coupled to a picosecond x-ray streak camera. Measurements of the time dependent behavior from Ti foils illuminated with intense laser pulses can be used to improve the understanding of recombination dynamics, electron transport, and phase transitions in strongly coupled dense plasma. This is important for the modeling of the compression phase in inertial confinement fusion research and the study of astrophysical environments.
Drag and flow reversal in mixed convection past a heated sphere

Axisymmetric simulation of mixed convection past a heated sphere presented in a recent paper of Mograbi and Bar-Ziv [J. Aerosol Sci. 36, 387 (2005)] reveals a “huge” recirculation in the opposing flow configuration at very small Reynolds numbers and at Richardson numbers exceeding unity, the size of which seems to adjust to a computational domain of any size. In this paper we show that, for Reynolds numbers as low as one, the flow is nonaxisymmetric and that its three dimensionality brings the recirculation within finite bounds. At higher Reynolds numbers (Re), the cases of Re=10 and 100 are considered at a fixed Prandtl number of 0.72. The flow becomes very soon not only three dimensional but also chaotic. Especially at higher Reynolds numbers (100), the arising convective structures do not resist the opposing flow and do not travel upstream more than several sphere diameters.
Bandwidth Versus Time Concentration: The Heisenberg–Pauli–Weyl Inequality

The main result is that for quite general weight functions v, w\[ \| f \|_2 \leq K\left( {\| {vf} \|_p + \| {w\hat f} \|_q } \right)\] for all tempered distributions f for which, roughly speaking, the right side makes sense, where $1 \leq p$, $q \leq \infty $, K is a constant independent of f, and $\hat f$ is the Fourier transform of f. As a corollary, if $\theta ,\phi \geq 0$ satisfy $\theta > {1 / {p^# }}$ and $\phi > {1 / {q^# }}$, where $t^# = {{2t} / {(t - 2)}}$, there exists $K = K(p,q,\theta ,\phi )$ such that \[ (1)\qquad \| f \|_2 \leq K\left( {\left\| {|x|^\theta f} \right\|_p + \left\| {|y|^\phi \hat f} \right\|_q } \right) \] for all f. In this case the inequality is equivalent to $\| f \|_2 \leq K\alpha ^{ - \alpha } (1 - \alpha )^{\alpha - 1} \| {|x|^\theta f} \|_p^\alpha \| {|y|^\phi \hat f} \|_q^{1 - \alpha } $ where $\alpha $ satisfies $\alpha (\theta - {1 / {p^# }}) = (1 - \alpha )(\phi - {1 / {q^# }})$. Hence it generalizes the classical uncertainty principle inequality (which is the ca.
Physical Interpretation of Koopmans' Theorem: A Criticism of the Current Didactic Presentation

Koopmans' theorem is one of the basic theorems learned in the preliminary courses of theoretical quantum chemistry. Its importance is not only related to ionization processes: it also gives the justification to the concept of "orbital energies". This concept is widely used in all qualitative description of electronic structure of atoms and molecules. In spite of such a widespread interest, the current didactic presentation of Koopmans' theorem in some widely used textbooks does not completely clarify the particular role played in its demonstration by the canonical Hartree-Fock orbitals. This step is essential to correctly define the orbital energies. In this paper we present a criticism of current didactic presentation of Koopmans' theorem and we propose a new didactic approach, which seems to us interesting from a pedagogical point of view. This paper is addressed to teachers and students of university courses in theoretical chemistry.
A consistent geometrically non‐linear approach for delamination

A new model is presented for the simulation of delamination in laminated composite materials. A key feature is that the material structure and the finite element mesh are uncoupled. The displacement discontinuities that arise during the delamination process are described mathematically using discontinuous functions. This leads naturally to a set of coupled equations for the continuous and the discontinuous parts of the response. Discontinuities can pass through solid finite elements arbitrarily, with the displacement jump continuous across element boundaries. The performance of the model is demonstrated for several problems of delamination and geometric instability. Copyright © 2002 John Wiley & Sons, Ltd.
Global Value Chain Governance of the Apparel Design Industry under the Background of Global Sustainable Economic Development

In recent years, there has been a significant rise in the importance of sustainability in business and personal life. Unsustainable techniques are used throughout the whole lifecycle of the clothing and textiles business, from the time it is made to the time it is recycled or thrown away. The garment sector and its customers must be ready for a more sustainable future as the government, corporations, and society turn their focus toward it. An investigation of how the apparel design industry (ADI) might adhere to the global value chain (GVC) in light of sustainable economic development (SED) and their relevance in China. This study analyzes the ADI moves up from one functional level to another within the global apparel value chain and what factors allow them to break into the global market. Researchers demonstrate that the existing sustainable operations in the AD industry are a long way from attaining the aims of economic development going hand in hand with the goals of economic sustainability by studying both the relevant literature and the industrial practices in the sector. This study relies on various case studies, proposes the “apparel global value chain” of governance-based sustainability, explores the implications of these models for areas with very varied degrees of development and diverse AD structures, and considers their implications for regional development and sustainability. As a development of a better knowledge of how fashion design contributes to economic sustainability. The study aims to examine how ADI uses economically sustainable techniques and how designers contribute to the creation of environmentally friendly goods.
Fractal structures and processes

Fractals and chaos are closely related. Many chaotic systems have fractal features. Fractals are self‐similar or self‐affine structures, which means that they look much of the same when magnified or reduced in scale over a reasonably large range of scales, at least two orders of magnitude and preferably more (Mandelbrot, 1983). The methods for estimating their fractal dimensions or their Hurst coefficients, which summarize the scaling relationships and their correlation structures, are going through a rapid evolutionary phase. Fractal measures can be regarded as providing a useful statistical measure of correlated random processes. They also provide a basis for analyzing recursive processes in biology such as the growth of arborizing networks in the circulatory system, airways, or glandular ducts.
2D He + pickup ion velocity distribution functions: STEREO PLASTIC observations

Context. He + pickup ions are either born from the ionization of interstellar neutral helium inside our heliosphere, the so-called interstellar pickup ions, or through the interaction of solar wind ions with small dust particles, the so-called inner source of pickup ions. Until now, most observations of pickup ions were limited to reduced 1D velocity spectra, which are insu ﬃ cient to study certain characteristics of the He + velocity distribution function (VDF). Aims. It is generally assumed that rapid pitch-angle scattering of freshly created pickup ions quickly leads to a fully isotropic He + VDF. In light of recent observations, this assumption has found to be oversimpliﬁed and needs to be reinvestigated. Methods. Using He + pickup ion data from the PLASTIC instrument on board the STEREO A spacecraft, we reconstruct a reduced form of the He + VDF in two dimensions. This allows us to study relative changes of the 2D He + VDF as a function of the conﬁguration of the heliospheric magnetic ﬁeld. Results. Our observations show that the He + VDF is highly anisotropic and even indicates that, at least for certain conﬁgurations of B , it is not fully gyrotropic. Our results further suggest, that the observed velocity and pitch angle of He + depends strongly on the local solar magnetic ﬁeld vector, B , the ecliptic longitude, λ , the solar wind speed, v sw , and the global distribution of B . Conclusions. We found two distinct signatures that systematically change as a function of the alignment of B : (1) a ring beam distribution that is most pronounced at w sw > 0 . 5 and likely attributed to interstellar He + ; (2) a beam signature aligned parallel to B that is most pronounced at w sw < 0 . 5 and attributed to inner-source He + . The strong anisotropy and the aforementioned dependencies of the He + VDF also imply that observations of 1D velocity spectra of He + pickup ions are potentially deceiving.
Radially scanned probe measurements in front of the CASTOR lower hybrid antenna

Lower hybrid waves (LHW) are used for non‐inductive generation of the electrical current in many tokamaks. However, in addition to the current drive, a parasitic acceleration of particles in front of the antennas takes place if the power is high enough. The small tokamak CASTOR allows to carry out measurements directly in the waves‐plasma interaction region, using movable Langmuir probes. This paper investigates fluctuations of the plasma parameters and electrical fields in the radially narrow layer in front of the CASTOR antenna, where a significant drop of floating potential has been observed recently [1]. Significant changes in these quantities have been found during LHW discharge phase. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stationary Phase with Neighboring Critical Points

The asymptotic behavior of a function which is represented by a definite integral depending on a parameter may depend on the value of the parameter. For example, the asymptotic behavior of the Bessel function Jn(k) for large values of k depends on the ratio k/n. If k/n >> 1, then JL,(k) will be an oscillating function, but if k/n << 1, then Jn(k) will be decreasing; while if k/n 1, J,, (k) will change from a monotonic function to an oscillating function. The problem which we wish to consider is this: Can we find an asymptotic representation for J,(k) which will be uniformly valid whether the ratio k/n is less than, equal to, or greater than one? This was done by R. E. Langer [1], T. M. Cherry [2], and F. W. J. Olver [3], but their work depended on the fact that the Bessel function was the solution of a second-order differential equation. What we do here is to obtain the same kind of asymptotic representation from a definite integral representation. We can state our problem in the following form: Suppose the function I(k) is defined by the contour integral
An “Unfolding” Latent Variable Model for Likert Attitude Data

Likert attitude data consist of responses to favorable and unfavorable statements about an entity, where responses fall into ordered categories ranging from disagreement to agreement. Social science and marketing researchers frequently use data of this type to measure attitudes toward an entity such as a policy or product. We focus on data on American and British attitudes toward their respective nations (“national pride”). We introduce a multidimensional unfolding model (MUM) to describe the relationship between the data and the attitudes underlying them. Unlike most existing models, the MUM allows the data to reflect not just attitudes, but also response style, which is defined as a consistent and content-independent pattern of response category selection such as a tendency to agree with all statements. The MUM can be used to model multiple attitudes, which allows researchers to expand their analysis of the data of interest to include all available Likert data so as to increase information on response style. For example, we include additional data on immigration attitudes to help distinguish the effects of response style and national pride on our data. The MUM can be used to fit linear models for the effects of background variables on attitudes. Resulting inferences about attitudes are adjusted for response style and should be less biased. Simulation results strongly suggest that, unlike Likert's popular scoring model, the MUM yields unbiased inferences even when there are unequal proportions of favorable and unfavorable statements.
Measurement of fluid properties using an acoustically excited atomic force microscope micro-cantilever

In this study, we develop a technique that can be used for extracting the properties of high viscosity Newtonian liquids at the microliter scale using an atomic force microscope. We obtained the responses of two different cantilevers in solutions of glycerin and water using thermal and acoustic frequency sweep excitations. The thermal excitation method cannot be used for liquids with viscosity substantially higher than 1 mPa s because of the existence of a noise floor which obscures the cantilever response. The acoustic frequency sweep excitation can overcome this limitation. The fluid properties were extracted by combining a theoretical model with the experimentally obtained results for the frequency sweep excitation. By using the cantilever phase response, errors of less than 14% in viscosity and density were achieved. This error can be explained by a local increase in fluid temperature of 3 °C due to the laser energy.
High-power laser projection displays

In this paper recent research on high-power laser displays for large display applications is reported. We discuss our compact high-power red-green-blue laser system for use as a light source based on a passively mode-locked solid-state laser with an optical parametric oscillator and sum- frequency mixing with very high efficiency and 19 W of white light. Concepts for power scaling to 35 W of white laser light are presented. A direct laser beam scanning technology is described which results in high resolution displays. Multi channel concepts as required in flight simulator applications are discussed. The laser light is modulated at 32 MHz using acousto-optic modulators with 75% diffraction efficiency. A high contrast ratio of 1:150,000 is achieved and has been successfully tested in novel planetarium applications. We also present performance and lifetime data of initial commercial laser display systems in the field.
Development of a 3D CZT detector prototype for Laue Lens telescope

We report on the development of a 3D position sensitive prototype suitable as focal plane detector for Laue lens telescope. The basic sensitive unit is a drift strip detector based on a CZT crystal, (~19×8 mm2 area, 2.4 mm thick), irradiated transversally to the electric field direction. The anode side is segmented in 64 strips, that divide the crystal in 8 independent sensor (pixel), each composed by one collecting strip and 7 (one in common) adjacent drift strips. The drift strips are biased by a voltage divider, whereas the anode strips are held at ground. Furthermore, the cathode is divided in 4 horizontal strips for the reconstruction of the third interaction position coordinate. The 3D prototype will be made by packing 8 linear modules, each composed by one basic sensitive unit, bonded on a ceramic layer. The linear modules readout is provided by a custom front end electronics implementing a set of three RENA-3 for a total of 128 channels. The front-end electronics and the operating logics (in particular coincidence logics for polarisation measurements) are handled by a versatile and modular multi-parametric back end electronics developed using FPGA technology.