A Coursebook in a Trilingual Classroom: To Use or not to Use

Coursebook use has proved to be a controversial issue in methodology. In this paper we refer to different writing on this subject, and take the argument a step further. As the way out, we look at an aspect of teaching English as a foreign language (EFL) that sooner or later every teacher comes up against – a need to write his/her materials. As our research has shown, this becomes of major importance in a trilingual classroom. Here, we also refer to some of the theoretical positions underlying third language acquisition (TLA)

Разработка алгоритма поэтапного совмещения перекрывающихся изображений для сравнительного анализа методов обнаружения ключевых точек

Memristive switches are promising devices for future nonvolatile nanocrossbar memory devices. In particular, complementary resistive switches (CRSs) are the key enabler for passive crossbar array implementation solving the sneak path obstacle. To provide logic along with memory functionality, "material implication" (IMP) was suggested as the basic logic operation for bipolar resistive switches. Here, we show that every bipolar resistive switch as well as CRSs can be considered as an elementary IMP logic unit and can systematically be understood in terms of finite-state machines, i.e., either a Moore or a Mealy machine. We prove our assumptions by measurements, which make the IMP capability evident. Local fusion of logic and memory functions in crossbar arrays becomes feasible for CRS arrays, particularly for the suggested stacked topology, which offers even more common Boolean logic operations such as AND and NOR

Проектирование основного электрооборудования конденсационной электростанции мощность 420 МВт

Объектом исследования является электрооборудование и структурная схема конденсационной электростанции мощностью 420 МВт. Цель работы заключается в проектировании основного электрического оборудования КЭС. В процессе исследования проводился выбор основного электрооборудования электростанции и разработка структурной схемы электрических соединений КЭС. Результатом исследования являются проведенные расчеты, на основе которых выбрано основное электрооборудование КЭС.The subject of the study is electrical equipment and a block diagram of a 420 MW condensation power plant. The aim of the work is to design the basic electrical equipment of IES. In the process of research, the main electric equipment of power plants was selected and the structural diagram of the electrical connections of the IES was developed. The result of the study is the calculations carried out, on the basis of which the main electrical equipment of IES was selected

HICFD – Highly Efficient Implementation of CFD Codes for HPC Many-Core Architectures

The objective of the German BMBF research project Highly Efficient Implementation of CFD Codes for HPC Many-Core Architectures (HICFD) is to develop new methods and tools for the analysis and optimization of the performance of parallel computational fluid dynamics (CFD) codes on high performance computer systems with many-core processors. In the work packages of the project it is investigated how the performance of parallel CFD codes written in C can be increased by the optimal use of all parallelism levels. On the highest level MPI is utilized. Furthermore, on the level of the many-core architecture, highly scaling, hybrid OpenMP/MPI methods are implemented. On the level of the processor cores the parallel SIMD units provided by modern CPUs are exploited

Crystallization dynamics and interface stability of strontium titanate thin films on silicon

Different physical vapor deposition methods have been used to fabricate strontium titanate thin films. Within the binary phase diagram of SrO and TiO2 the stoichiometry ranges from Ti rich to Sr rich, respectively. The crystallization of these amorphous SrTiO3 layers is investigated by in situ grazing-incidence X-ray diffraction using synchrotron radiation. The crystallization dynamics and evolution of the lattice constants as well as crystallite sizes of the SrTiO3 layers were determined for temperatures up to 1223 K under atmospheric conditions applying different heating rates. At approximately 473 K, crystallization of perovskite-type SrTiO3 is initiated for Sr-rich electron beam evaporated layers, whereas Sr-depleted sputter-deposited thin films crystallize at 739 K. During annealing, a significant diffusion of Si from the substrate into the SrTiO3 layers occurs in the case of Sr-rich composition. This leads to the formation of secondary silicate phases which are observed by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy

Integration of ferroelectric thin films into silicon based microsystems

The integration of ferroelectric materials will enhance the functionality of conventional microsystems. The converse piezoelectric effect can be used for the fabrication of integrated actuators, which will help to realize integrated high frequency switches. The aim of this thesis is the integration of ferroelectric thin films into silicon based microsystems. Therefore, PZT thin films have been deposited on platinum coated silicon substrates by chemical solution deposition (CSD) and are characterized regarding their electrical and electromechanical properties. It has been shown that PZT with a composition of 45% zirconium and 55% titanium shows a very high piezoelectric coefficient of 115 pm/V. Moreover it has been proved that no electromechanical fatigue occurs, if the material is driven with unipolar electric fields. Lead hafnate titanate (PHT) is a variation of PZT and doping with 10% lanthanum leads to an electrostrictive behavior. Thereby, the piezoelectric coefficient is around 60 pm/V and nearly independent on the applied electric field, which leads to a linear strain behavior. The investigation of the permittivity of barium strontium titanate (BST) shows a linear decrease with increasing temperatures. This effect is used for the detection of infrared radiation. For the fabrication of silicon based microsystems a variety of technologies have been developed for the structuring of ferroelectric thin films, platinum electrodes, silicon and silicon dioxide. The release of cantilevers and membranes is performed by back etching with TMAH, isotropic etching with SF6 plasma and by a sacrificial process. The latter one is based on silicon on insulator substrates, whereby the buried oxide is etched with HF-vapor. Furthermore, a process for the fabrication of freestanding copper bridges was developed. A number of cantilevers relying on the converse piezoelectric effect were fabricated and characterized with a laser vibrometer regarding the displacement and the resonance frequency. The measurement results are in good agreement with finite element simulations. A maximum displacement of 80 µm was measured at an applied voltage of only five volts. This is several times more than can be achieved with electrostatic actuation. Further development leads to the fabrication of a microrelay, which than was integrated in an high frequency switch. Simulations show that this novel piezoelectric concept reaches a switching level of more than 20 dB up to 20 GHz. Further fabricated microsystems are thin film bulk acoustic resonators (TFBAR) relying on the generation of acoustic waves due to electrostriction and showing a resonance at 6.2 GHz as well as a dielectric bolometer for the detection of infrared radiation. Beyond, experiments with PZT coated metal foils exhibit higher spontaneous polarization than obtained on platinum coated silicon. From the experiments, cantilevers using the metal foil as flexible substrate were fabricated with fine mechanical techniques showing a displacement of 35 µm

Integration of ferroelectric thin films into silicon based microsystems

The integration of ferroelectric materials will enhance the functionality of conventional microsystems. The converse piezoelectric effect can be used for the fabrication of integrated actuators, which will help to realize integrated high frequency switches. The aim of this thesis is the integration of ferroelectric thin films into silicon based microsystems. Therefore, PZT thin films have been deposited on platinum coated silicon substrates by chemical solution deposition (CSD) and are characterized regarding their electrical and electromechanical properties. It has been shown that PZT with a composition of 45% zirconium and 55% titanium shows a very high piezoelectric coefficient of 115 pm/V. Moreover it has been proved that no electromechanical fatigue occurs, if the material is driven with unipolar electric fields. Lead hafnate titanate (PHT) is a variation of PZT and doping with 10% lanthanum leads to an electrostrictive behavior. Thereby, the piezoelectric coefficient is around 60 pm/V and nearly independent on the applied electric field, which leads to a linear strain behavior. The investigation of the permittivity of barium strontium titanate (BST) shows a linear decrease with increasing temperatures. This effect is used for the detection of infrared radiation. For the fabrication of silicon based microsystems a variety of technologies have been developed for the structuring of ferroelectric thin films, platinum electrodes, silicon and silicon dioxide. The release of cantilevers and membranes is performed by back etching with TMAH, isotropic etching with SF6 plasma and by a sacrificial process. The latter one is based on silicon on insulator substrates, whereby the buried oxide is etched with HF-vapor. Furthermore, a process for the fabrication of freestanding copper bridges was developed. A number of cantilevers relying on the converse piezoelectric effect were fabricated and characterized with a laser vibrometer regarding the displacement and the resonance frequency. The measurement results are in good agreement with finite element simulations. A maximum displacement of 80 µm was measured at an applied voltage of only five volts. This is several times more than can be achieved with electrostatic actuation. Further development leads to the fabrication of a microrelay, which than was integrated in an high frequency switch. Simulations show that this novel piezoelectric concept reaches a switching level of more than 20 dB up to 20 GHz. Further fabricated microsystems are thin film bulk acoustic resonators (TFBAR) relying on the generation of acoustic waves due to electrostriction and showing a resonance at 6.2 GHz as well as a dielectric bolometer for the detection of infrared radiation. Beyond, experiments with PZT coated metal foils exhibit higher spontaneous polarization than obtained on platinum coated silicon. From the experiments, cantilevers using the metal foil as flexible substrate were fabricated with fine mechanical techniques showing a displacement of 35 µm