High-resolution detection of defects by one dimensional spatial filtering

The capabilities of a one-dimensional filtering method for the detection of defects in periodic structures are derived by a detailed theoretical analysis. The signal-to-noise ratio is evaluated as a function of system parameters and a way is described to overcome the disturbing effect of phase defects. Finally, an extremely simple system is described which demonstrated the detection of defects below 2 μm. This demonstrated detection capability was limited by the available test mask and not by the detection system. This work was partially supported by “Kulso” Ltd.     

Magnetoelastic domain wall wave in a ferromagnet

We show that in a magnetically and elastically uniaxial ferromagnetic insulator, a new type of inhomogeneous elastic wave may propagate along a 180° domain wall. A numerical example is given.     

On topologically finite-dimensional simple <Emphasis Type="Italic">C</Emphasis>*-algebras

We show that, if a simple C*-algebra A is topologically finite-dimensional in a suitable sense, then not only K₀(A) has certain good properties, but A is even accessible to Elliott’s classification program. More precisely, we prove the following results:If A is simple, separable and unital with finite decomposition rank and real rank zero, then K₀(A) is weakly unperforated.If A has finite decomposition rank, real rank zero and the space of extremal tracial states is compact and zero-dimensional, then A has stable rank one and tracial rank zero. As a consequence, if B is another such algebra, and if A and B have isomorphic Elliott invariants and satisfy the Universal coefficients theorem, then they are isomorphic.In the case where A has finite decomposition rank and the space of extremal tracial states is compact and zero-dimensional, we also give a criterion (in terms of the ordered K₀-group) for A to have real rank zero. As a byproduct, we show that there are examples of simple, stably finite and quasidiagonal C*-algebras with infinite decomposition rank.Supported by: EU-Network Quantum Spaces - Noncommutative Geometry (Contract No. HPRN-CT-2002-00280) and Deutsche Forschungsgemeinschaft (SFB 478).     

Cutsets and anti-chains in linear lattices

Consider the poset, ordered by inclusion, of subspaces of a four-dimensional vector space over a field with 2 elements. We prove that, for this poset, any cutset (i.e., a collection of elements that intersects every maximal chain) contains a maximal anti-chain of the poset. In analogy with the same result by Duffus, Sands, and Winkler [D. Duffus, B. Sands, P. Winkler, Maximal chains and anti-chains in Boolean lattices, SIAM J. Discrete Math. 3 (2) (1990) 197-205] for the subset lattice, we conjecture that the above statement holds in any dimension and for any finite base field, and we prove some special cases to support the conjecture.     

Anisotropic Bianchi type V perfect fluid cosmological models in Lyra’s geometry

The law of variation for mean Hubble’s parameter with average scale factor, in an anisotropic Bianchi type V cosmological space–time, is discussed within the frame work of Lyra’s manifold. The variation of Hubble’s parameter, which gives a constant value of deceleration parameter, generates two types of solutions for the average scale factor; one is the power-law and the other one is of exponential form. Using these two forms, new classes of exact solutions of the field equations have been found for a Bianchi type V space–time filled with perfect fluid in Lyra’s geometry by considering a time-dependent displacement field. The physical and kinematical behaviors of the singular and non-singular models of the universe are examined. Exact expressions for look-back time, luminosity distance and event horizon versus redshift are also derived and their significance are discussed in detail. It has been observed that the solutions are compatible with the results of recent observations.     

Effects of Ball-Milling Atmosphere on the Thermoelectric Properties of TAGS-85 Compounds

Inspired by the high ZT value lately attained in Ar-protected ball-milled nanocrystalline p-BiSbTe bulk alloy, we report herein an investigation of the effects of ball-milling atmosphere on the thermoelectric (TE) properties of the traditional TE material (GeTe)₈₅(AgSbTe₂)₁₅ (TAGS-85). TAGS-85 samples were prepared via a melting–quenching–annealing process, and then ball-milled in different atmospheres and subsequently densified using a spark plasma sintering technique. The Seebeck coefficient, electrical conductivity, thermal conductivity, and Hall coefficient were measured as a function of temperature from 10 K to 310 K. It was found that different ball-milling atmospheres, i.e., air, liquid N₂ (LN₂), and Ar, profoundly affected the TE properties. A state-of-the-art figure of merit ZT ≈ 0.30 was attained at 310 K in the Ar-ball milled sample. The results are discussed in terms of the carrier concentration, mobility, crystallinity, and the grain boundary scattering.     

Une ambition éditoriale “universelle et confraternelle” : le bulletin bibliographique de L&#x27;Enseignement mathématique (1899–1920)

In 1899 Henri Fehr and Charles Laisant founded L'Enseignement mathématique (EM) with the ambition to involve teachers in the then-growing internationalization movement of mathematics. To this purpose, their editorial project gave an important place to a bibliographical bulletin reviewing periodicals which could be of interest for the world of mathematical education. This article is dedicated to the study of this bulletin, from its creation to the 1920s, and to the initiatives and choices that Laisant and Fehr made to carry out this internationalist editorial ambition, as well as to the limits and constraints of their project. During that time, many bibliographical initiatives for periodicals developed in the mathematical press, which can be considered as a first form of interaction between journals. Our study will concern initially the year 1899 and this interaction in which EM took part, dealing at first with the bulletin of EM, then, secondly, with the confrontation between bibliographical sections of other journals. Lastly, considering the first thirty years of the 20th century, we will study the different dynamics at work in the world of mathematical periodicals which the EM serves to depict.     

基于Z85C30的动目标识别系统的串行通信设计

在介绍了动目标识别系统（Mobile Identification System）关键技术和串行通信控制器Z85C30的基础上,对MIS的关键技术HDLC和TDMA进行了分析,然后从硬件和软件两方面给出了一种实现MIS协议帧的具体方案。该方案采用ZILOG公司的串行通信控制器Z85C30进行设计,以单片机STC89C58RD＋为处理器,文中同时给出了部分实验数据。     

Riemann theta functions periodic wave solutions and rational characteristics for the nonlinear equations

In this paper, based on a multidimensional Riemann theta function, a lucid and straightforward generalization of the Hirota-Riemann method is presented to explicitly construct multiperiodic Riemann theta functions periodic wave solutions for nonlinear equations such as the Caudrey-Dodd-Gibbon-Sawada-Kotera equation and (2+1)-dimensional breaking soliton equation. Among these periodic waves, the one-periodic waves are well-known cnoidal waves, their surface pattern is one-dimensional, and often they are used as one-dimensional models of periodic waves. The two-periodic waves are a direct generalization of one-periodic waves, their surface pattern is two-dimensional so that they have two independent spatial periods in two independent horizontal directions. A limiting procedure is presented to analyze in detail, asymptotic behavior of the multiperiodic waves and the relations between the periodic wave solutions and soliton solutions are rigorously established. This generalized Hirota-Riemann method can also be demonstrated on a class variety of nonlinear difference equations such as Toeplitz lattice equation.