Wyniki wyszukiwania - BazTech

1

Synthesis of 23-Oxa-22-deoxo Analogues of OSW-1 Aglycone

Kruszewska A., Wilczewska A., Wojtkiewicz A., Morzycki J.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 4

611-615

EN

Four ether analogues of OSW-1 aglycone were obtained by alkylation of a steroid alcohol with alkyl bromide. During theWilliamson reaction promoted by sodium hydride in addition to alkylation, an unusual dehydrogenation of secondary alcohol was observed.

2

A Novel Approach to Signal Processing in FMCW Radar

Wojtkiewicz A., Nałęcz M., Kulpa K., Rytel-Andrianik R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2002

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Vol. 50, Nr 4

347--359

EN

New possibilities of Digital Signal Processing (DSP) in Frequency Modulated Continuous Wave (FMCW) radar are presented. By the use of a transformation belonging to the class of higher-order bilinear time-frequency transforms (such as Polynomial Phase Transform PPT, Generalized Ambiguity Function GAF or Generalized Wigner-Ville Distribution GWVD) one can estimate coefficients of polynomial phase of the intermediate frequency (IF) signal. Two practical cases with non-negligible higher order coefficients are considered: compensation of nonlinear modulator and estimation of moving target acceleration, velocity and range. In the latter case, target velocity introduces to the processed signal a linear phase shift that can be measured using Fourier transform. Similarly, target acceleration introduces parabolic shift to the signal phase, which in turn enables the estimation of the acceleration. The article includes the description of a relationship between quadratic coefficient and object acceleration as well as estimation methods for this coefficient. Examples based on recorded signals from working FMCW radar prove usefulness of proposed methods.

3

The simple analysis method of nonlinear frequency distortions in FMCW radar

Kulpa K. S., Wojtkiewicz A., Nałęcz M., Misiurewicz J.

Journal of Telecommunications and Information Technology

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2001

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nr 4

26-29

EN

The paper presents a simple method for estimating nonlinear frequency distortions of linear frequency modulated (LFM) signals used in FMCW radars. This method, derived from the polynomial model of the nonlinear FM signal phase, is based on finding the maximum of two-dimensional chirp-like transform of the IF video signal. The IF signal is obtained by mixing transmitted FM signal with its delayed copy. Using suggested transform we show that the presented method is able to detect and classify signal distortions.

4

Dielektryki bramkowe dla nowych generacji układów scalonych

Łukasiak L., Jakubowski A., Beck R. B., Wojtkiewicz A., Korwin-Pawłowski M., Rużyłło J.

Elektronika : konstrukcje, technologie, zastosowania

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2001

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Vol. 42, nr 2

27-29

PL

W artykule przedstawiono wpływ redukcji grubości tlenku bramkowego w przyrządach MOS na ich działania, wytwarzanie oraz charakteryzację. Przedyskutowano także zalety rozwiązania polegającego na zastąpieniu SiO2 materiałem o wyższej przenikalności elektrycznej w formie dielektryku pojedynczego lub podwójnego.

EN

The paper presents the consequences of the reduction of gate oxide thickness in MOS devices on their operation, manufacturing and characterization. The advantages of replacing SiO2 with high-k materials (in the form of both single and stacked dielectric) are discussed, too.