Two-Way Protocol with Imperfect Devices

The security of a deterministic quantum scheme for communication, namely the LM05 [1], is studied in presence of a lossy channel under the assumption of imperfect generation and detection of single photons. It is shown that the scheme allows for a rate of distillable secure bits higher than that pertaining to BB84 [2]. We report on a first implementation of LM05 with weak pulses.     

In situ impedance study of the Y-Ni thin film under electrochemical hydrogenation

A thin film of yttrium Y (150 nm) protected by a 6 nm coating of nickel Ni on a glass substrate was completely hydrogenated in a 1 M NaOH electrolyte at a constant negative current until the transparent Y tri-hydride phase was achieved and hydrogen gas evolution from the electrode began. A series of impedance measurements were performed in situ during the electrochemical experiment to study the properties of the system as dependent on hydrogenation degree and time of relaxation. The equivalent electrical circuit (EEC) simulations were performed with a Randles-like scheme R₀[R₁CPE₁], where R₀ is the thin film electrode resistance, R₁ the charge transfer resistance and CPE₁ is the capacitive constant phase element. The behavior of all the components of the EEC undergoes a clear transition when the hydrogenation degree of the electrode is approximated to its maximum value (H to Y ratio 2.7) and electrochemical process changes from hydrogen uptake to hydrogen evolution.     

Thermally stimulated creep (TSCr) study of viscoelastic behavior and physical aging of a polymeric matrix composite for spacecraft structures

Thermally Stimulated Creep (TSCr) mechanical spectroscopy has been used to analyze molecular movements in KMU‐4lcarbon/epoxy composite material around the glass transition temperature. This technique is powerful to characterize the microstructure and micromechanical properties of the epoxy matrix and their evolution upon thermal aging. Three cooperative submodes have been distinguished by resolving the fine structure of the material complex α‐retardation mode. The elementary processes constituting this mode possess activation enthalpies and preexponential factors that strongly depend on the thermal history of the sample. The activation parameters of the composite are subject to perceptible evolution due to postcuring degradation. The α‐mode associated complex spectrum shifts towards higher temperatures by 27°C as a consequence of a series of quenching in the temperature range 260 to 0°C; the material shows a rise in the fragility and a deterioration in the crack‐growth resistance qualities. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 342–350, 2002     

Ability of reflection high energy electron diffraction (RHEED) to observe structural modifications in ion-implanted and annealed GaAs

GaAs 100 wafers were implanted and later annealed by using three different techniques: furnace thermal annealing (FTA), flash lamp (RTA) and low-power laser annealing (LPLA). The resulting modifications of the structure were studied by RHEED. The RHEED pattern analysis indicates that: (a) A well annealed structure is observed after thermal treatment in furnace at 850 °C for 30 min; (b) the particular RTA employed leads to some texturing, but is not sufficient to provide good structural effects; (c) best annealing under our conditions is obtained by the LPLA technique, especially for low ion doses (less than 10¹³ cm^–2); (d) variable-glancing-angle RHEED is an effective and convenient method to investigate the ion induced disorder in crystals at small depths.     

High‐quality pagination for publishing

The problem of line breaking consists of finding the best way to split paragraphs into lines. It has been cleverly addressed by the total‐fit algorithm exposed by Knuth and Plass in a well‐known paper. Similarly, page‐breaking algorithms break the content flow of a document into page units. Formatting languages—such as the World Wide Web Consortium standard Extensible Stylesheet Language Formatting Objects (XSL‐FO)—allow users to set which content should be kept in the same page and how many isolated lines are acceptable at the beginning/end of each page. The strategies most formatters adopt to meet these requirements, however, are not satisfactory for many publishing contexts as they very often generate unpleasant empty areas. In that case, typographers are required to manually craft the results in order to completely fill pages. This paper presents a page‐breaking algorithm that extends the original Knuth and Plass line‐breaking approach and produces high‐quality documents without unwanted empty areas. The basic idea consists of delaying the definitive choice of breaks in the line‐breaking process in order to provide a larger set of alternatives to the actual pagination step. The algorithm also allows users to decide the set of properties to be adjusted for pagination and their variation ranges. An application of the algorithm to XSL‐FO is also presented, with an extension of the language that allows users to drive the pagination process. The tool, named FOP+, is a customized version of the open‐source Apache Formatting Objects Processor formatter. Copyright © 2011 John Wiley & Sons, Ltd.     

An extended finite element formulation for contact in multi‐material arbitrary Lagrangian–Eulerian calculations

Multi‐material Eulerian and arbitrary Lagrangian–Eulerian methods were originally developed for solving hypervelocity impact problems, but they are attractive for solving a broad range of problems having large deformations, the evolution of new free surfaces, and chemical reactions. The contact, separation, and slip between two surfaces have traditionally been addressed by the mixture theory, however the accuracy of this approach is severely limited. To improve the accuracy, an extended finite element formulation is developed and example calculations are presented. As a side benefit, the mixture theory is eliminated from the multi‐material formulation, eliminating the issues associated with the equilibration time between adjacent materials. By design, the new formulation is relatively simple to implement in existing multi‐material codes, parallelizes without difficulty, and has a low memory burden. Copyright © 2006 John Wiley & Sons, Ltd.     

Solving large multiple-depot multiple-vehicle-type bus scheduling problems in practice

We consider the multiple-depot multiple-vehicle-type scheduling problem (MDVSP) which arises in public transport bus companies and aims to assign buses to cover a given set of timetabled trips with consideration of practical requirements, such as multiple depots and vehicle types as well as depot capacities. An optimal schedule is characterized by minimal fleet size and minimal operational costs including costs for empty movements and waiting time. It is well-known that the MDVSP is NP-hard.Although progress has recently been made in solving large practical MDVSP to optimality with time-space network models, current optimization technology sets limits to the model size that can be solved. In order to approach very large practical instances we propose a two-phase method which produces close to optimal solutions. This modeling approach enables us to solve real-world problem instances with thousands of scheduled trips by direct application of standard optimization software. Furthermore, we introduce the concept of depot groups for the case that a bus may return in the evening into another depot than where it started in the morning.     

TES microcalorimeter readout via transformer

Readout configuration for Transition Edge Sensor (TES) electrically coupled to a low noise warm front-end via transformer is studied. The study was aimed at the implementation of the readout involved in imaging with microcalorimeter detector arrays using frequency multiplexing technique (Appl. Phys. Lett. 81(1) (2002) 159). A model describing both TES electrothermal reaction and the readout response is investigated. Contribution of electronic noise to TES energy resolution is calculated. Prospective readout architecture with TES electrical biasing from the warm readout side is introduced. The architecture allows building of large imaging detector arrays with TES. It is shown that an unprecedented combination of imaging and spectrometry features can be achieved with TES readout via transformer.