Artykuły (WFTIiMS)
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Pozycja Dielectric relaxation modes in liquid crystalline mixture(Wydawnictwo Politechniki Łódzkiej, 2009) Wojciechowski, MarekMixture of two liquid crystalline compounds (which do not exhibit antiferroelectric or ferrielectric phase separately) shows ferrielectric phase in a broad temperature range. The dielectric spectroscopy technique was used for investigation of collective molecular motions in the mixture. Two relaxation modes were detected in the ferrielectric phase and the soft mode in the SmA phase. The temperature dependence of the parameters of the dielectric relaxation modes are presented and discussed.Pozycja Kerr constant of Fomblin Z(Wydawnictwo Politechniki Łódzkiej, 2008) Ledzion, Rafał; Karolczak, Stefan; Górski, Piotr; Kucharczyk, WłodzimierzThe Kerr constant B of polyperfluoroethylenemethylene oxide Fomblin Z has been determined within the temperature range 295-323K. At 300K the constant B was found to be equal to 1.7 10(-15) m/V2. The results obtained indicate usefulness of this oligomeric compound as an immersion liquid in measurements of the quadratic electrooptic effect and electrostriction in crystals.Pozycja Microstructure of NWA 4435 meteorite(Politechnika Łódzka, 2008) Szurgot, Marian; Polański, KrzysztofElemental composition, mineral composition and microstructure of NWA 4435 meteorite found in 2006 has been studied by analytical electron microscopy and optical microscopy. It was established that the main meteorite minerals: olivines, pyroxenes, troilite, and graphite identified in the sample represent extraterrestrial minerals typical of carbonaceous chondrites. Chemical and mineral composition, petrologic type of chondrules, their abundance and sizes, the presence of troilite, and abundance of oxidized iron phases confirm CV3 class of this chondrite.Pozycja Application of electrooptic modulators for divergent light beam(Wydawnictwo Politechniki Łódzkiej, 2009) Izdebski, MarekAnalysis of electrooptic modulators of the light strength working with divergent light beam is performed numerically employing the Jones matrices method. The approach allows to consider small inaccuracies in cutting and alignment of electrooptic crystal and the divergence of entering light beam. The results show that the divergence typical for gas lasers should not affect significantly the work of electrooptic modulators even for large electrooptic crystals, while diode lasers may be used with modulators only in the form of precise modules equipped with colimation optics.Pozycja Effect of temperature on the refractive index and Kerr effect of the transformer oil Nynas Nytro Taurus(Wydawnictwo Politechniki Łódzkiej, 2009) Górski, Piotr; Ledzion, Rafał; Sadowski, Marcin; Kucharczyk, WłodzimierzThe temperature dependence of refractive index of the mineral transformer oil Nynas Nytro Taurus within the range 278-385K is determined. Changes with temperature in the quadratic electrooptic response of the oil are investigated. The results obtained indicate the usefulness of the oil as immersion liquid in measurements of the quadratic electrooptic effect and electrostriction in crystals.Pozycja Numerical study of ionic current in a dielectric liquid layer subjected to square wave voltage(Wydawnictwo Politechniki Łódzkiej, 2009) Derfel, Grzegorz; Opioła, PawełIonic current flowing in a thin layer of dielectric liquid under the action of square wave voltage was studied numerically. Quasi-blocking electrodes and equal mobilities of unions and cations were assumed. Field dependent dissociation and recombination were taken into account. The spatial distributions of ion concentrations and the ionic current density during a single voltage cycle were calculated as functions of time. A bump of the current was observed at suitably high voltage, low ion content and low frequency. This effect resulted from redistribution of ions which occurred in the whole layer. Two gradually diffusing groups of ions wandering across the layer, one formed by cations and the other formed by anions, could be distinguished. There was no unambiguous relationship between the moment at which the bump occurred and the value of ions mobility.Pozycja Numerical studies of significance of anchoring strength energy for behaviour of flexoelectric homeotropic nematic layer subjected to DC electric field(Wydawnictwo Politechniki Łódzkiej, 2009) Buczkowska, Mariola; Grzelczak, KatarzynaElastic deformations of homeotropic nematic liquid crystal layers subjected to a d.c. electric field were studied numerically. The flexoelectric properties of the nematic material and the presence of ionic space charge were taken into account. The influence of anchoring strength W was investigated. The calculations were performed for layers with negative dielectric anisotropy and negative sum of flexoelectric coefficients. Strongly blocking electrodes were assumed. The threshold voltages for deformations were computed for several anchoring strength values and for low, moderate and high ion content. Its value was nearly proportional to W for low anchoring strength and saturated at some high value of W. The director distributions were also determined. This task was complicated by the presence of space charge of ions. Remarkable change of deformation character was noticed when the ion content and anchoring strength were varied.Pozycja Microscopic investigations of Shisr 007 meteorite(Wydawnictwo Politechniki Łódzkiej, 2009) Szurgot, Marian; Polański, Krzysztof; Burski, MaciejElemental composition, mineral composition and microstructure of Shisr 007 meteorite found in 2001 have been studied by analytical electron microscopy. It was established that the main meteorite minerals: olivines, pyroxenes, troilite, and graphite identified in the sample represent extraterrestrial minerals typical of olivine-pyroxene achondrites. Chemical and mineral composition, and texture confirm previous classification of this achondrite as ureilite.Pozycja Activation processes for two chosen aromatic hydrocarbon materials(Wydawnictwo Politechniki Łódzkiej, 2009) Kania, Sylwester; Kuliński, JanuszThe activation process and the transport process for electrons in the tetracene layers and holes in the p-quaterphenyl layers is considered. Obtained results may suggests the hopping transport through the localized states near the Fermi level as a dominant kind of transport. Observed dependence of the conductivity on the vapor concentration of the activator molecules may suggest that tetracene is better for utilization as a vapour sensors.Pozycja Dielectric characteristics of antiferroelectric liquid crystalline mixture(Wydawnictwo Politechniki Łódzkiej, 2008) Wojciechowski, MarekMixture of liquid crystals, with induced antiferroelectric phase has been studied by means of dielectric spectroscopy. The dielectric measurements were carried out in a cell with gold electrodes at planar orientation. The characteristic of dielectric relaxation modes in all phases existing in the mixture are presented.