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Richard Dabrowski APEC국제교육협력원 2004 Asia-Pacific Cybereducation Journal Vol.1 No.1
While many have extolled the potential of Webbased instruction, rarely has this enthusiasm been backed by reliable evidence. Ruth Colvin Clark and Richard E. Mayer in £-Learning and the Science of Instruction (2003) elaborate pedagogical principles which should be followed to maximize the effectiveness of hypermedia and web-based instruction (terms they combine as e-leaming). They explicitly cite the research on which they base their claims as well as provide examples from training programs in current use to demonstrate how their principles might be applied. The result is a definitive handbook of guidelines for instructional designers that is based on the best-available academic research, written in an accessible language which minimizes the use of academic jargon.
A. DABROWSKI,M. GLOGOWSKI,P. KUBIAK 한국자동차공학회 2016 International journal of automotive technology Vol.17 No.4
This article presents selected results of preliminary tests that were carried out on a four-stroke engine with spark ignition (SI), as well as a mechanical oscillator with pneumatic support - the so-called pneumatic energy accumulator (PAE). This solution is expected to provide a significant improvement in the efficiency of SI engines in a range of partial loads. Due to the self-regulatory properties of the combustion chamber, the engine equipped with this type of oscillator is called an Active Combustion Chambers engine or, in short, an ACC engine. The aim of this study was preliminary to evaluate the possibility of controlling the thermodynamic processes that occur at the end of a compression stroke and at the beginning of an expansion stroke. It also aimed to carry out a preliminary assessment of a simulation model of a PAE (US 872039-B2). This article includes a diagram of an ACC engine with a brief description of the physical model of the oscillator. It also includes the mathematical description that was used for the simulation. As part of the analysis that was carried out, the article presents graphs of the simulation studies and empirical research.
Increase of YBa2Cu3O7 critical currents by Mo substitution and high-pressure oxygen annealing
Los A.,Dabrowski B.,Rogacki K. 한국물리학회 2021 Current Applied Physics Vol.27 No.-
We have previously shown for powders that Mo substitution into the CuO chains of YBa2Cu3O7 can create effective pinning centres which significantly increase the critical current density (jc) in 7 T field by a factor of 4 and 10 at 50 and 60 K, respectively (Rogacki et al., 2006) [1]. The present work reports on the influence of the Mo substitution and high-pressure oxygen annealing on the pinning properties and critical currents of YBa2Cu3- xMoxO7-d by comparing pure (x = 0, d > 0) and substituted (x = 0.03, d < 0) single crystals. Pinning properties have been investigated by measurements of magnetization loops and calculations of jc in the ab-plane, in the temperature range from 2 to 90 K and in fields up to 14 T. Depending on the Mo substitution and the oxygen treatment, several types of pinning centres increasing jc have been revealed and analysed in the frame of Dew- Hughes’ and Kramer’s models.
High Optical Anisotropy Nematic Single Compounds and Mixtures
Gauza, Sebastian,Kula, Przemyslaw,Dabrowski, Roman,Sasnouski, Genadz,Lapanik, Valeri The Korean Institute of Electrical and Electronic 2012 Transactions on Electrical and Electronic Material Vol.13 No.1
We have designed, synthesized, and evaluated the physical properties of some high birefringence (${\Delta}n$) isothiocyanato biphenyl-bistolane liquid crystals. These compounds exhibit ${\Delta}n^-$ 0.4-0.7 at room temperature and wavelength $\lambda$=633 nm. Laterally substituted short alkyl chains and fluorine atom eliminate smectic phase and lower the melting temperature. The moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. Several mixtures based on those compounds were formulated and its physical properties evaluated.
Wideband Low-Reflection Transmission Lines for Bare Chip on Multilayer PCB
Rashad Ramzan,Jonas Fritzin,Jerzy Dabrowski,Christer Svensson 한국전자통신연구원 2011 ETRI Journal Vol.33 No.3
The pad pitch of modern radio frequency integrated circuits is in the order of few tens of micrometers. Connecting a large number of high-speed I/Os to the outside world with good signal fidelity at low cost is an extremely challenging task. To cope with this requirement, we need reflection-free transmission lines from an on-chip pad to on-board SMA connectors. Such a transmission line is very hard to design due to the difference in on-chip and on-board feature size and the requirement for extremely large bandwidth. In this paper, we propose the use of narrow tracks close to chip and wide tracks away from the chip. This narrow-to-wide transition in width results in impedance discontinuity. A step change in substrate thickness is utilized to cancel the effect of the width discontinuity, thus achieving a reflection-free microstrip. To verify the concept, several microstrips were designed on multilayer FR4 PCB without any additional manufacturing steps. The TDR measurements reveal that the impedance variation is less than 3 ohm for 50 ohm microstrip and S11 better than –9 dB for the frequency range 1 GHz to 6 GHz when the width changes from 165 um to 940 um, and substrate thickness changes from 100 um to 500 um.
High Optical Anisotropy Nematic Single Compounds and Mixtures
Sebastian Gauza,Przemyslaw Kula,Roman Dabrowski,Genadz Sasnouski,Valeri Lapanik 한국전기전자재료학회 2012 Transactions on Electrical and Electronic Material Vol.13 No.1
We have designed, synthesized, and evaluated the physical properties of some high birefringence (Δn) isothiocyanato biphenyl-bistolane liquid crystals. These compounds exhibit Δn~ 0.4-0.7 at room temperature and wavelength λ=633 nm. Laterally substituted short alkyl chains and fluorine atom eliminate smectic phase and lower the melting temperature. The moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. Several mixtures based on those compounds were formulated and its physical properties evaluated.