Search

It was considered the peculiarities of prior laser treatment influence on the structure and properties of nitrided layers on steel surface. The general regularities of influence of laser beam parameters and the pattern of treatment on contact fatigue and tribological properties of the coatings. Strengthening of metal products according to the grid-cell scheme of discrete processing increases the contact fatigue strength and wear resistance of the coating due to the minimization of the stress-deformed state. Розглянуто особливості впливу схеми попередньої лазерної обробки на будову і властивості азотованих шарів на сталях. Установлено основні закономірності впливу контурно – променевих схем лазерного зміцнення на контакту втомну міцність і трибологічні характеристики покриттів. Визначено, що зміцнення металевих виробів за сітчасто – стільниковою схемою дискретної обробки підвищує контактну втомну міцність та зносостійкість покриття за рахунок мінімізації напружено деформованого стану.

In this paper, we investigate the problem of dominant point detection on digital curves which consists in finding points with local maximum curvature. Thanks to previous studies of the decomposition of curves into sequence of discrete structures [1] , [2] , [3] , namely maximal blurred segments of width ν [4] , an initial algorithm has been proposed in [5] to detect dominant points. However, an heuristic strategy is used to identify the dominant points. We now propose a modified algorithm without heuristics but a simple measure of angle. In addition, two applications are as well presented: (1) polygonal simplification to reduce the number of detected dominant points by associating a weight to each of them, and (2) classification using the polygon issued from the reduced dominant points. The experimental results demonstrate the efficiency and robustness of the proposed method.

Eleven complexes and adduct have been synthesized and studied by infrared. The suggested structures are discrete with tetrahedral, trigonal bipyramidal, square planar or octahedral environments around Zn, Ni, Hg and Cu centres – the coordination number is eight in the yttrium compound and ten in the dysprosium one-. The maleate anion behaves as a bidentate, a monochelating, a bichelating or a tetradentate ligand while the formiate anion behaves as a monodentate ligand. For compounds containing a protonated amine or a methanol molecule, when hydrogen bonds are considered a supramolecular architecture may be obtained.

Memristors constitute a promising functional component for information storage and in-memory computing in flexible and stretchable electronics including wearable devices, prosthetics, and soft robotics. Despite tremendous efforts made to adapt conventional rigid memristors to flexible and stretchable scenarios, stretchable and mechanical-damage-endurable memristors, which are critical for maintaining reliable functions under unexpected mechanical attack, have never been achieved. Here, the development of stretchable memristors with mechanical damage endurance based on a discrete structure design is reported. The memristors possess large stretchability (40%) and excellent deformability (half-fold), and retain stable performances under dynamic stretching and releasing. It is shown that the memristors maintain reliable functions and preserve information after extreme mechanical damage, including puncture (up to 100 times) and serious tearing situations (fully diagonally cut). The structural strategy offers new opportunities for next-generation stretchable memristors with mechanical damage endurance, which is vital to achieve reliable functions for flexible and stretchable electronics even in extreme and highly dynamic environments. Submitted/Accepted version T.W. and Z.C. contributed equally to this work. The project was supported by the National Research Foundation (NRF), Prime Minister’s office, Singapore, under its NRF Investigatorship (NRF-NRFI2017-07), Singapore Ministry of Education (MOE2017-T2-2-107 and MOE2019-T2-2-022), and the Agency for Science, Technology and Research (A*STAR) under its Advanced Manufacturing and Engineering (AME) Programmatic Funding Scheme (project #A18A1b0045).

espanolEl articulo aborda las principales etapas de la formacion y el desarrollo de la prosa fragmentaria alemana en los siglos XIX y XX. Utilizando los materiales de obras novelescas alemanas del siglo XX, los autores analizan los dispositivos artisticos que motivan la discrecion de la narracion y determinan su funcion artistica: la manifestacion y estructuracion de la informacion estetica. A partir del analisis de los dispositivos artisticos, se identifica el contenido estetico de la estructura discreta de la novela, que depende de la vision del mundo de los escritores. La estructura discreta resulto ser una forma de arte universal que configuro los rasgos tipologicos de la novela moderna. portuguesO artigo trata das principais etapas da formacao e desenvolvimento da prosa fragmentaria alema nos seculos 19-20. Usando os materiais dos romances alemaes do seculo XX, os autores analisam os dispositivos artisticos que motivam a discricao da narrativa e determinam sua funcao artistica - a manifestacao e estruturacao da informacao estetica. Com base na analise dos dispositivos artisticos, e identificado o conteudo estetico da discreta estrutura da novela, que depende da visao de mundo dos escritores. A estrutura discreta provou ser uma forma de arte universal que moldou as caracteristicas tipologicas do romance moderno. EnglishThe article deals with the key stages of the formation and development of German fragmentary prose in the 19th–20th centuries. Using the materials from German novels of the 20th century, the authors analyze the artistic devices that motivate the discreteness of the narrative and determine their artistic function – the manifestation and structuring of aesthetic information. Based on the analysis of artistic devices, the aesthetic content of the discrete novel structure is identified which depends on the writers' worldview. The discrete structure has proven to be a universal art form that has shaped the typological features of the modern novel.

Discrete structure manipulation is a fundamental technique for many problems solved by computers. BDDs/ZDDs have attracted a great deal of attention for twenty years, because those data structures are useful to efficiently manipulate basic discrete structures such as logic functions and sets of combinations. Recently, one of the most interesting research topics related to BDDs/ZDDs is Frontier-based search method, a very efficient algorithm for enumerating and indexing the subsets of a graph to satisfy a given constraint. This work is important because many kinds of practical problems can be efficiently solved by some variations of this algorithm. In this article, we present recent research activity related to BDD and ZDD. We first briefly explain the basic techniques for BDD/ZDD manipulation, and then we present several examples of the state-of-the-art algorithms to show the power of enumeration.

International audience; Polygonal approximation is often involved in many applications of computer vision, image processing and data compression. In this context, we are interested in digital curves extracted from contours of objects contained in digital images. In particular, we propose a fully discrete structure, based on the notion of blurred segments, to study the geometrical features on such curves and apply it in a process of polygonal approximation. The experimental results demonstrate the robustness of the proposed method to local variation and noise on the curve.

The extent to which time-dependent fracture criteria affect the dynamic behavior of fracture in a discrete structure is discussed in this work. The simplest case of a semi-infinite isotropic chain of oscillators has been studied. Two history-dependent criteria are compared to the classical one of threshold elongation for linear bonds. The results show that steady-state regimes can be reached in the low subsonic crack speed range where it is impossible according to the classical criterion. Repercussions in terms of load and crack opening versus velocity are explained in detail. A strong qualitative influence of history-dependent criteria is observed at low subsonic crack velocities, especially in relation to achievable steady-state propagation regimes.

Discrete structures are foundational material for computer science and mathematics, which are related to set theory, symbolic logic, inductive proof, graph theory, combinatorics, probability theory, etc. Many problems solved by computers can be decomposed into discrete structures using simple primitive algebraic operations. It is very important to represent discrete structures compactly and to execute efficiently tasks such as equivalency/validity checking, analysis of models, and optimization. Recently, BDDs (Binary Decision Diagrams) and ZDDs (Zero-suppressed BDDs) have attracted a great deal of attention, because they efficiently represent and manipulate large-scale combinational logic data, which are the basic discrete structures in various fields of application. Although a quarter of a century has passed since Bryant's first idea, there are still a lot of interesting and exciting research topics related to BDD and ZDD. BDD/ZDD is based on in-memory data processing techniques, and it enjoys the advantage of using random access memory. Recent commodity PCs are equipped with gigabytes of main memory, and we can now solve large-scale problems which used to be impossible due to memory shortage. Thus, especially since 2000, the scope of BDD/ZDD methods has increased. This survey paper describes the history of, and recent research activity pertaining to, techniques related to BDD and ZDD.

Рассмотрены примеры практического использования режущих инструментов из быстрорежущих сталей, твердых сплавов и керамики с износостойкими защитными покрытиями. Показано, что инструменты с покрытиями, имеющими дискретную структуру, характеризуются большей стойкостью и обеспечивают получение обработанной поверхности с меньшей шероховатостью. The examples of practical use of cutting tools made of high-speed steel, carbide and ceramic wear-resistant coating. It is shown that the coated tools having a discrete structure, characterized by longer lifetime and provides the treated surface with less roughness.

A new general decomposition theory inspired by modular graph decomposition is presented. This helps in unifying modular decomposition on different structures, including (but not restricted to) graphs. Moreover, even in the case of graphs, this new notion called homogeneous modules not only captures the classical graph modules but also allows handling 2-connected components, star-cutsets, and other vertex subsets.The main result is that most of the nice algorithmic tools developed for the modular decomposition of graphs still apply efficiently on our generalisation of modules. Besides, when an essential axiom is satisfied, almost all the important properties can be retrieved. For this case, an algorithm given by Ehrenfeucht, Gabow, McConnell and Sullivan [A. Ehrenfeucht, H. Gabow, R. McConnell, S. Sullivan, An O(n2) Divide-and-Conquer Algorithm for the prime tree decomposition of two-structures and modular decomposition of graphs, Journal of Algorithms 16 (1994) 283–294.] is generalised and yields a very efficient solution to the associated decomposition problem.

In this paper, we investigate the problem of dominant point detection on digital curves which consists in finding points with local maximum curvature. Thanks to previous studies of the decomposition of curves into sequence of discrete structuresi¾?[5---7], namely maximal blurred segments of width $$\nu $$i¾?[13], an initial algorithm has been proposed ini¾?[14] to detect dominant points. However, an heuristic strategy is used to identify the dominant points. We now propose a modified algorithm without heuristics but a simple measure of angle. In addition, an application of polygonal simplification is as well proposed to reduce the number of detected dominant points by associating a weight to each of them. The experimental results demonstrate the efficiency and robustness of the proposed method.

Natural processes and phenomena often display discrete structure. The discrete nonlinear Schrödinger equations are used in both physics and biology to model periodic optical structures and energy transfer in proteins. In this study, we present a new application of the (G′/G)-expansion method to special, coupled, discrete, nonlinear Schrödinger-type equations. This application is shown to be an effective tool for constructing solitary and periodic wave profiles with arbitrary parameters. In addition, we provide rational solutions that have not been explicitly computed before.