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Search results for: LIQUID CRYSTALS
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Liquid crystals for information processing.
PublicationW pracy przedstawiono właściwości ciekłych kryształów, zastosowania tych materiałów w akwizycji, przetwarzaniu i przesyłaniu informacji. Omówiono urządzenia i systemy wisualizacji informacji wykorzystujące ciekłe kryształy. Zaprezentowano zastosowania elemetów ciekłokrystalicznych w urządzeniach pamięci optycznej.
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Liquid Crystals in Analytical Chemistry: A Review
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Calculation of vibrational spectra for cyanobiphenyl liquid crystals
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Liquid crystals thermography for technical and biomedical application
PublicationW artykule opisano termografię ciekłokrystaliczną jako technikę wykorzystu-jącą termochromatyczne ciekłe kryształy do badań technicznych i biomedycz-nych. W szczególności dotyczy to badań wymiany ciepła i masy, chorób skór-nych i podobnych. Praca zawiera ilustracje z badań przeprowadzonych przezautorów.
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Modelling of optical components made of liquid crystals and liquid crystalline polymers
PublicationW artykule przedstawiono koncepcję wykorzystania ciekłych kryształów i polimerów ciekłokrystalicznych do budowy dwójłomnych elementów optycznych - płytek opóźniających, pryzmatów Wollastona i Nomarskiego. Przedstawiono wyniki modelowania pryzmatów Nomarskiego wykonanych z polimerów ciekłokrystalicznych i dokonano porównania ich właściwości z właściwościami pryzmatów wykonanych z typowych materiałów dwójłomnych.
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Layer contraction of smectic liquid crystals and the compensation model
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Thermochromic liquid crystals applied for heat transfer research
PublicationAutorzy opisali własne wieloletnie doświadczenia z badań wymiany ciepła, w których wykorzystali termochromatyczne ciekłe kryształy. Obejmowały one badania przepływów w kanałach o różnorakiej konfiguracji, badania w przestrzeniach zamkniętych oraz podczas zmiany stanu skupienia badanego płynu.
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The use of thermochromic liquid crystals in heat transfer research
PublicationW ostatnich latach ciekłe kryształy zostały z powodzeniem zastosowane do wizualizacji pola temperatury w stanach ustalonych i przejściowych na różnych powierzchniach. Analiza otrzymanych obrazów początkowo była skomplikowana, ale dzięki zastosowaniu obróbki komputerowej pomiary stały się o wiele dokładniejsze i szybsze. W opracowaniu przedstawiono przegląd badań, w których zastosowano automatyczną technikę analizy obrazów, a prowadzone...
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Liquid Crystals, PIV and IR-Photography in Selected Technical and Biomedical Applications
PublicationThermochromic liquid crystals (TLC), Particle Image Velocimetry (PIV), Infrared Imaging Themography (IR) and True-Colour Digital Image Processing (TDIP) have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. These four tools (based on the desktop computers) have come together during the past two decades to produce a powerful advanced...
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Surface phenomena in discotic liquid crystals investigated using polarized FTIR transmission spectroscopy
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Anomalous temperature dependence of layer spacing of de Vries liquid crystals: Compensation model
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Peculiar hydrogen bonding behaviour of water molecules inside the aqueous nanochannels of lyotropic liquid crystals
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All-fiber tunable devices based on high-index photonic crystal fibers filled with liquid crystals
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Critical behaviour of the smectic A*–C* phase transition and electroclinic effect of ferroelectric liquid crystals with terphenyl rigid core
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Thermal decomposition of some aromatic azomonoethers. Part II. Non-isothermal study of three liquid crystals in dynamic air atmosphere
PublicationW ramach pracy zweryfikowano stabilność termiczną trzech barwników azowych o właściwościach ciekłokrystalicznych - potencjalnych prekursorów do otrzymywania warstw stosowanych w optyce nieliniowej. Zarejestrowano przebiegi TG, DTG, DTA oraz DSC jak również analizowano skład gazów powstających podczas rozpadu za pomocą przystawki FTIR. Przeprowadzono analizę kinetyki rozkładu, wyznaczając energię aktywacji procesu.
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Analysis of the vibrational spectra of chiral liquid crystalline thioesters
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Kinetics of photochromic reactions of substituted azobenzenes in solutions, and in liquid crystalline and polymer matrices
PublicationBadano kinetykę fotochromowych reakcji pochodnych azobenzenu: eterów koronowych z resztą benzenu i 4-metoksy-4´-halogenoazobenzenów zdolnych do tworzenia fazy ciekłokrystalicznej. Fotoaktywne związki rozpuszczano w alkanach, polimerach i w ciekłokrystalicznej matrycy. Izomeryzacja odpowiada kinetyce pierwszego rzędu w niektórych polimerach, jednakże stwierdzono zróżnicowanie stałych szybkości reakcji. Termiczna izomeryzacja cis-trans...
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The surface photoconductivity in molecular layers
PublicationW pracy przedstawiono rezultaty analizy fotoprądów powierzchniowych w cienkich warstwach tetracenu i pentacenu. W szczególności badano wpływ obecności defektów strukturalnych w warstwach na charakterystyki fotoprądów i transport nośników ładunku.
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Electric field dependence of the probability of charge carriers recombination
PublicationBadano wpływ zewnętrznego pola elektrycznego na prawdopodobieństwo rekombinacji nośników ładunku w molekularnych ciałach stałych. Przybliżenie analityczne wykazuje, że prawdopodobieństwo to maleje ze wzrostem pola elektrycznego. Otrzymane wyniki mogą być pomocne w wyjaśnieniu spadku wydajności elektroluminescencji w jednowarstwowych diodach elektroluminescencyjnych w zakresie wysokich pól elektrycznych.
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Preparation and characterization of biopolymeric films with magnetic properties
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The influence of UV-irradiation on the poly(vinyl alcohol)/hyaluronic acid film properties
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The physicochemical properties of 3D materials based on hyaluronic acid modified by tannic acid addition
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Preparation and characterization of silk fibroin/collagen sponge modified by chemical cross-linking
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Polymer films based on silk fibroin and collagen - the physico-chemical properties
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Physico-chemical properties of three-component mixtures based on chitosan, hyaluronic acid and collagen
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Studies of Exfoliated Graphite (EG) for Heavy Oil Sorption
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The Use of Liquid Crystal Thermography in Selected Technical and Medical Applications—Recent Development
PublicationThermochromic liquid crystals (TLC) and true-colour digital image processing have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. Thin coatings of TLC at surfaces are utilized to obtain detailed temperature distributions and heat transfer rates for steady or transient processes. Liquid crystals also can be used to make the temperature and velocity fields in liquids visible...
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The use of liquid crystal thermography TLC and particle image velocimetry PIV in selected technical applications
PublicationNowadays, the energy cost is very high and this problem is carried out to seek techniques for improvement of the aerothermal and thermal (heat flow) systems performances in different technical applications. The transient and steady-state techniques with liquid crystals for the surface temperature and heat transfer coefficient or Nusselt number distribution measurements have been developed. The flow pattern produced by transverse...
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Signal Processing in the Investigation of Two-phase Liquid-gas Flow by Gamma-ray Absorption
Publicationn this paper, the use of the gamma-absorption method applied in the investigation of the two-phase liquid-gas flow in the pipeline is described. An example of its application to the air transported by water in a horizontal pipeline is evaluated. In the measurements, Am-241 radioactive sources and probes with Nal (Tl) scintillation crystals have been used. The signals from the radiometric set were used to determine the velocity...
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A Note on Reduced Strain Gradient Elasticity
PublicationWe discuss the particular class of strain-gradient elastic material models which we called the reduced or degenerated strain-gradient elasticity. For this class the strain energy density depends on functions which have different differential properties in different spatial directions. As an example of such media we consider the continual models of pantographic beam lattices and smectic and columnar liquid crystals.
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Studies on the solid-liquid equilibria and intermolecular interactions Urea binary mixtures with Sulfanilamide and Sulfacetamide
PublicationThe binary phase diagrams of Sulfanilamide-Urea (SN-U) and Sulfacetamide-Urea (SC-U) were measured using differential scanning calorimetry technique (DSC). Both examined mixtures were found to form simple binary eutectics. The limited miscibility in the solid state observed by DSC, proving inability of co-crystallization in new multi-molecular form, was also confirmed using PXRD and FTIR-ATR measurements of solid dispersions...
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Why is the cubic structure preferred in newly formed ice?
PublicationMolecular dynamics was employed to explain the preference for the cubic structure in newly formed crystals of ice. The results showed that in supercooled liquid water the molecules connected by hydrogen bonds are more likely to adopt relative orientations similar to the ones characteristic for cubic ice. The observed preference for certain relative orientations of molecules in the hydrogen-bonded pairs results in the higher probability...
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Flow visualization and heat transfer investigations on the flat plate with streamwise pressure gradient
PublicationPaper presents experimental investigations results for film cooling on a flat plate. The main objective of the design is the streamwise pressure distribution on the flat plate as in the blade cascade. The transient and steady-state technique with liquid crystals for the surface temperature distribution with film cooling has been used in experiments in a low speed wind tunnel.
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LCT, PIV and IR Imaging Detection in Selected Technical and Biomedical Applications
PublicationPaper presents the brief summary of the history of Thermochromic liquid crystals (TLC), Particle Image Velocimetry (PIV) and Infrared Imaging Themography (IR). Principal methods and tools are described and some examples are presented. With this objective, a new experimental technique have been developed and applied to the study of heat and mass transfer and for biomedical diagnosis. Selected results of experiments using these methods...
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On the material symmetry group for micromorphic media with applications to granular materials
PublicationWithin the framework of the theory of nonlinear elastic micromorphic continua we introduce the new definition of the local material symmetry group. The group consists of ordered triples of second- and third-order tensors describing such changes of a reference placement that cannot be recognized with any experiment. Using the definition we characterize the micromorphic isotropic media, micromorphic fluids, solids and special intermediate...
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Epoxy/Ionic Liquid-Modified Mica Nanocomposites: Network Formation–Network Degradation Correlation
PublicationWe synthesized pristine mica (Mica) and N-octadecyl-N’-octadecyl imidazolium iodide (IM) modified mica (Mica-IM), characterized it, and applied it at 0.1–5.0 wt.% loading to prepare epoxy nanocomposites. Dynamic differential scanning calorimetry (DSC) was carried out for the analysis of the cure potential and kinetics of epoxy/Mica and epoxy/Mica-IM curing reaction with amine curing agents at low loading of 0.1 wt.% to avoid particle...
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Signals features extraction in radioisotope liquid-gas flow measurements using wavelet analysis
PublicationKnowledge of the structure of a flow is significant for the proper conduct of a number of industrial processes. In this case, a description of a two-phase flow regimes is possible by use of the time-series analysis in time, frequency and state-space domain. In this article the Discrete Wavelet Transform (DWT) is applied for analysis of signals obtained for water-air flow using gamma ray absorption. The presented method was illustrated...
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LCT, PIV and IR Imaging Detection in Selected Technical and Biomedical Applications
PublicationThermochromic liquid crystals (TLC), Particle Image Velocimetry (PIV) and Infrared Imaging Themography (IR) have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. These four tools (based on the desktop computers) have come together during the past two decades to produce a powerful advanced experimental technique as a judgment of quality of information that cannot be obtained...
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Controlling the size and morphology of precipitated calcite particles by the selection of solvent composition
PublicationCalcium carbonate particles were obtained in the reaction of calcium hydroxide with carbon dioxide at 65°C. Initial Ca(OH)2 suspensions were prepared in pure water and aqueous solutions of ethylene glycol or glycerol of the concentration range up to 20% (vol.). The course of reaction was monitored by conductivity measurements. Precipitated solids were analyzed by FTIR, XRD, SEM and the particles size distribution was determined...
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Structure redetermination, transport and thermal properties of the YNi3Al9 compound
PublicationSingle crystals of completely ordered variant of the YNi3Al9 compound were grown by self-flux method with excess of aluminum. The crystal structure of the title compound was redetermined from single crystal X-ray diffraction data. The structure adopts ErNi3Al9 type, space group R32, parameters of the unit cell a = 7.2838(2) Å, c = 27.4004(8) Å. The growth of relatively large single crystals of the YNi3Al9 compound, having completely...
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Effect of different crystalline structures on W/O and O/W/O wax emulsion stability
PublicationtThe possibility of emulsion stabilization using mineral and vegetable wax particles only (without sur-factant) was investigated. Mineral waxes, paraffin wax and ceresin, and a vegetable wax, carnauba wax,were used. The content of the wax particles and the water to oil proportion were found crucial for thestability of all emulsions. Some emulsions were also produced with a liquid wax (i.e. jojoba oil). Themultiple light scattering...
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Electrochemical Stability of Few-Layered Phosphorene Flakes on Boron-Doped Diamond: A Wide Potential Range of Studies in Aqueous Solutions
PublicationTwo-dimensional phosphorene has attracted great interest since its discovery as a result of its extraordinary properties. Two-dimensional single crystals of phosphorene can be useful for electrochemical (EC) sensing applications due to their enhanced surface-to-volume ratio. We proposed to investigate the electrochemical performance of phosphorene deposited directly on boron-doped diamond (BDD) electrodes. Noncovalent interaction...
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Preparation of platinum modified titanium dioxide nanoparticles with the use of laser ablation in water
PublicationWe report on the preparation method of nanocrystalline titanium dioxide modified with platinum by using nanosecond laser ablation in liquid (LAL). Titania in the form of anatase crystals has been prepared in a two-stage process. Initially, irradiation by laser beam of a titanium metal plate fixed in a glass container filled with deionized water was conducted. After that, the ablation process was continued, with the use of a platinum...
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Structure of Microemulsion Formulated with Monoacylglycerols in the Presence of Polyols and Ethanol
PublicationThe influence of polyols as cosurfactants (propylene glycol PG; glycerol G) and short chain alcohol as a cosolvent (ethanol EtOH) on the formation and solubilization capacity of the systems: hexadecane/monoacylglycerols (MAG)/polyol/water:EtOH, at 60C, was investigated. Electrical conductivity measurement, and the DSC method were applied to determine the structure and type of microemulsions formed. The dimension of the droplets...
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Dehydration converts DsbG crystal diffraction from low to high resolution
PublicationDiffraction quality crystals are essential for crystallographic studies of protein structure, and the production of poorly diffracting crystals is often regarded as a dead end in the process. Here we show a dramatic improvement of poorly diffracting DsbG crystals allowing high-resolution diffraction data measurement. Before dehydration, the crystals are fragile and the diffraction pattern is streaky, extending to 10 Å resolution....
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Optical activity and electro-optic effect of l-arginine doped KDP single crystals
PublicationWe have used the modified polarimetric methods to study optical activity (OA) in the potassium dihydrogenphosphate (KDP) crystals doped with 0.7, 1.4 and 3.8 wt% L-arginine (L-arg) amino acid. Crystals were grown by the temperature reduction method. Small changes of the absolute eigen waves ellipticity and OA values in doped crystals were noted. We have experimentally determined the signs of OA in the [1 00] and [01 0] directions...
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On the origin of surface imposed anisotropic growth of salicylic and acetylsalicylic acids crystals during droplet evaporation
PublicationIn this paper droplet evaporative crystallization of salicylic acid (SA) and acetylsalicylic acid (ASA) crystals on different surfaces, such as glass, polyvinyl alcohol (PVA), and paraffin was studied. The obtained crystals were analyzed using powder X-ray diffraction (PXRD) technique. In order to better understand the effect of the surface on evaporative crystallization, crystals deposited on glass were scraped off. Moreover,...
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Computational Study of Molecular Interactions in ZnCl2(urea)2 Crystals as Precursors for Deep Eutectic Solvents
PublicationDeep eutectic solvents (DESs) are now enjoying an increased scientific interest due to their interesting properties and growing range of possible applications. Computational methods are at the forefront of deciphering their structure and dynamics. Type IV DESs, composed of metal chloride and a hydrogen bond donor, are among the less studied systems when it comes to their understanding at a molecular level. An important example...
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Growth, Crystal Structure and Magnetic Characterization of Zn-Stabilized CePtIn4
PublicationThe growth and characterization of CePtIn4, stabilized by 10% Zn substitution for In, is reported. The new material is orthorhombic, space group Cmcm (No. 63), with lattice parameters a = 4.51751(4) Å, b = 16.7570(2) Å, and c = 7.36682(8) Å, and the refined crystal composition has 10% of Zn substituted for In, i.e., the crystals are CePt(In0.9Zn0.1)4. Crystals were grown using a self-flux method: only growths containing Zn yielded...
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The contribution of Hans von Wartenberg to the development of the Czochralski method
PublicationThe contribution of Hans von Wartenberg to the development of the Czochralski Method for pulling single crystals is often overlooked. He was its earliest adopter, having introduced the use of seed crystals, and his detailed description of the method was the basis for its subsequent dissemination.