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Wyniki wyszukiwania dla: NONCENTROSYMMETRIC STRUCTURES
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Arbutin: Isolation, X-ray structure and computional studies
PublikacjaArbutin, an active component originated from Serratula quinquefolia for skin-whitening use and treating skin related allergic inflammation, was characterized by microanalysis, FTIR, UV-Vis, multinuclear NMR spectroscopy, and single crystal X-ray diffraction method. The geometries of the studied compound were optimized in singlet states using the density functional theory (DFT) method with B3LYP functional. Electronic spectra were...
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Why is the cubic structure preferred in newly formed ice?
PublikacjaMolecular 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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The structure of demand and its economic consequences for urban transport
PublikacjaThe structure of demand for urban transport services, determined by the share of passengers entitled to free and reduced fares, is an important factor influencing its economic condition. The aim of this article is to present the results of research into the structure of demand for urban transport as well as its economic consequences. The article begins by considering the nature of the determinants and consequences of the public...
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Deposition of phosphate coatings on titanium within scaffold structure
PublikacjaPurpose: Existing knowledge about the appearance, thickness, and chemical composition of phosphate coatings on titanium inside porous structures is insufficient. Such knowledge is important for the design and fabrication of porous implants. Methods: Metallic scaffolds were fabricated by selective laser melting of 316L stainless steel powder. Phosphate coatings were deposited on Ti sensors placed either outside the scaffolds or...
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Structure and thermoelectric properties of bismuth telluride—Carbon composites
PublikacjaCarbon nanotubes and amorphous carbon have been introduced into a bismuth telluride matrix (0.15 and 0.30 wt.% ratio) to investigate the influence of the carbon on the composite’s thermoelectric properties. Composites with well-dispersed additives have been obtained by sonication and ball-milling methodology. Carbon nanotubes and an amorphous carbon addition led to a decrease in electric conductivity from 1120 S/cm to 77 S/cm....
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Resonant Frequencies in Microstrip Structure with Omega Medium Substrate
PublikacjaThe paper presents the research on a rectangular microstrip structure with multilayer substrate containing dielectric and omega medium layers. The effect of pseudochiral medium layer location in the substrate and its thickness on the resonant frequency of the rectangular microstrip structure is investigated. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields. Utilizing the continuity...
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System of monitoring of the Forest Opera in Sopot structure and roofing
PublikacjaThe authors present a solution realized in Forest Opera (name in Polish: Opera Leśna) in Sopot (Poland) in connection with the modernization and construction of a new roof. The complicated structure of the roof of the facility and the used covering in form of membrane made of technical fabric required (for security reasons) to install the unit of devices allowing for the continuous geodetic monitoring of the facility. Monitoring...
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A structure and design of a novel compact UWB MIMO antenna
PublikacjaIn the paper, a concept and design procedure of a novel compact MIMO slot antenna is presented. In order to achieve a better filling of available space, individual antennas are constrained to a triangular shape and optimized for a reduced size. The MIMO structure is then assembled using the two of previously designed antennas in orthogonal arrangement. Surrogate-assisted numerical optimization involving variable-fidelity electromagnetic...
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Novel structure and design of compact UWB slot antenna
PublikacjaIn this paper, a novel structure of a compact UWB slot antenna is presented along with a simulation-driven design optimization algorithm for adjusting geometry parameters of the device. Our primary objective is to obtain small footprint of the structure while maintaining its acceptable electrical performance. It is achieved by introducing sufficiently large number of geometry degrees of freedom, including increased number of parameterized...
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Silo music - mechanism of dynamic flow and structure interaction
PublikacjaArtykuł omawia zjawisko muzyki silosowej. Wykonano pomiary dynamiczne przyspieszeń, częstotliwości i postaci drgań własnych. Zaproponowano nowa hipotezę powstawania efektów dynamicznych podczas przepływu silosowego.
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Silo music - mechanism of dynamic flow and structure interaction
PublikacjaArtykuł omawia zjawisko muzyki silosowe. Wykonano pomiary dynamiczne przyspieszeń, częstotliwości i postaci drgań własnych. Zaproponowano nowa hipotezę powstawania efektów dynamicznych podczas przepływu silosowego.
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Polar boundary conditions along a soil structure interface.
PublikacjaAnalizowano problem strefy kontaktu między gruntem a konstrukcją. Obliczenia wykonano stosując mikropolarne prawo sprężysto-plastyczne oraz mikropolarne prawo hipoplastyczne. Analizie poddano problem płynięcia silosowego oraz ścinania wąskiej warstwy.
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Structural Analysis of 3,5-Bistrifluoromethylhydrocinnamic Acid
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Computer modeling and testing of structural metamaterials
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Nanotechnologies in Development of Structural Materials and Biomaterials
PublikacjaThe nanometric materials and technologies resulted in nanostructures are reviewed. The examples of nanomaterials are shown. The typical nanotechnologies, including plastic deformation, mechanical attrition, controlled detonation, hot plasma jet synthesis, laser vaporisation, CVD and PVD, mechanical milling, annealing, ultrasonic irradiation, nanolithography, electrocrystallisation, electrospinning, sol-gel method, cryogenic laser-enhanced...
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How to teach sustainable structural engineering.
PublikacjaNa podstawie analizy toretycznej i doświadczeń praktycznych - autora jako profesora politechniki, badacza i praktykującego inżyniera - uzyskanych w niniejszym pięćdziesięcioleciu, przedstawiono ogólny stan obecny zrównoważonej inżynierii i jej akcentowanie w Politechnice Gdańskiej.
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Structural characterization of plasmenylcholine photooxidation products.
PublikacjaZbadano fotoutlenianie PPlsC w obecności rozpuszczalnego w wodzie sensybilizatora (uczulacza) jakim jest tetrasulfonian ftalocyjaniny zawierający aluminium(III). Stosując metody chromatograficzne (HPLC) wyizolowano, zidentyfikowano oraz scharakteryzowano zasadnicze produkty powstające w obecności tlenu podczas ciągłego naświetlania światłem widzialnym o długości fali 610nm.
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Structural studies of titanium oxide multilayers
PublikacjaW pracy przedstawiono wyniki badań cienkich warstw TiO2 przy wykorzystaniu dyfrakcji rentgenowskiej i anihilacji pozytonów. Warstwy były wytwarzane różnymi metodami. Badania pozwalają na określenie optymalnych, z punktu widzenia późniejszych zastosowań, parametrów warstw.
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The structural investigations of the bronze based CuMn12Al7Fe3Ni3
PublikacjaStopy miedzi są stosowane w przemyśle morskim, ze względu na swoje właściwości takie jak odporność erozyjna, odporność korozyjna czy też wysoka wytrzymałość korozyjno-zmęczeniowa. Oczywistym jest, iż właściwości brązów są wyższe niż mosiądzów.W pracy przedstawiono wyniki badań brązu CuMn12Al7Fe3Ni3 (BM12733), który jest najpowszechniej stosowany na okrętowe pędniki śrubowe. Zebrano i zaprezentowano wyniki badania składu chemicznego,...
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Lipopolysaccharides: regulated biosynthesis and structural diversity
PublikacjaThe cell envelope of Gram-negative bacteria contains two distinct membranes, an inner (IM) and an outer (OM) membrane, separated by the periplasm, a hydrophilic compartment that includes a thin layer of peptidoglycan. The most distinguishing feature of such bacteria is the presence of an asymmetric OM with phospholipids located in the inner leaflet and lipopolysaccharides (LPSs) facing the outer leaflet. The maintenance of this...
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Influence of geometric imperfections on capacities of silo structures loaded with pressure below atmospheric
PublikacjaPrzedstawiono probabilistyczną analizę nośności aluminiowego silosu ze wstępnymi imperfekcjami geometrycznymi obciążonego podciśnieniem. Imperfekcje opisano za pomocą dyskretnych odchyłek przyjętych zgodnie z maksymalnymi niedokładnościami dopuszczonymi przez normy. Ponadto wygenerowano imperfekcje płaszcza silosu, stosując jednorodne i niejednorodne pola losowe. Wykonano numeryczne obliczenia geometrycznie i materiałowo nieliniowe.
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QSAR Analysis of Selected Antimicrobial Structures Belonging to Nitro-derivatives of Heterocyclic Compounds
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Syntheses, structures and chemical properties of unsaturated oligo(alkylene-ester-ether)diols
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Mathematical Modelling of a Seismic Isolation System to Protect Structures during Damaging Earthquakes
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Digital image correlation method: a versatile tool for engineering and art structures investigations
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Application of Hybrid FEM-DIC Method for Assessment of Low Cost Building Structures
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Impact of Mining Exploitation on Properties with Engineering Structures by Local Urban Development Plans
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Lessons from application of the UNRES force field to predictions of structures of CASP10 targets
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FT-Raman Spectroscopy as a Tool to Study the Secondary Structures of Wheat Gliadin Proteins
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Does Nitrogen Fertilization Affect the Secondary Structures of Gliadin Proteins in Hypoallergenic Wheat?
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Crystal structures of the Bacillus subtilis prophage lytic cassette proteins XepA and YomS
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Influence of geometric imperfections on capacities of silo structures loaded with pressure below atmospheric
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Mitigating the Energy Consumption and the Carbon Emission in the Building Structures by Optimization of the Construction Processes
PublikacjaFor decades, among other industries, the construction sector has accounted for high energy consumption and emissions. As the energy crisis and climate change have become a growing concern, mitigating energy usage is a significant issue. The operational and end of life phases are all included in the building life cycle stages. Although the operation stage accounts for more energy consumption with higher carbon emissions, the...
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Nanomechanical Stability of Aβ Tetramers and Fibril-like Structures: Molecular Dynamics Simulations
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Mechanical properties for preliminary design of structures made from PVC coated fabric
PublikacjaIn this paper, laboratory tests necessary for the identification of non-linear elastic immediate properties of the PVC coated polyester fabric (like AF 9032) are described. The material parameters are specified on the basis of the uniaxial tensile tests in the warp and weft directions as well as on the base of the biaxial tensile tests. For the identification process techniques based on the least squares method are used. The authors...
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EXPERIMENTAL AND NUMERICAL STUDY ON COLLISIONS BETWEEN STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
PublikacjaIn the time of high urbanization, the need to build closely-spaced structures forces the designers to take into account earthquake-induced collisions between adjacent buildings and their effects on the response of structures. Past and recent investigations confirmed that interactions between adjacent buildings during earthquakes may cause serious damages to the structural elements and may even lead to total collapse of the structure....
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Effective method for determining environmental loads on supporting structures for offshore wind turbines
PublikacjaThis paper presents a description of an effective method for determining loads due to waves, current and wind acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was...
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublikacjaAbstract: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete...
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The Syntheses and Crystal Structures of the First Disiloxane-1,3-dithiol and Its Cadmium Complex.
PublikacjaThe new silicon–sulfur compound: disiloxane-1,3-dithiol was obtained from silicon disulfide and 2,6-diisopropylphenol in a reaction catalyzed by imidazole or 4-(dimethylamino)pyridine (DMAP). Crystal structure of disiloxane–1,3-dithiol reveals a close-to-linear Si–O–Si angle and a mutual trans position of the two hydrosulfido groups. The compound forms a chelating mononuclear complex with cadmium ions.
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Influence of Spatial Structures of 316L Stainless Steel on Its Cavitation Erosion Resistance
PublikacjaCavitation erosion performance of modified macroscopic internal structure 316L stainless steel was investigated. The samples processed by means of SLM method were subjected to cavitation erosion test. The scanning electron microscope Philips 30/ESEM was used to examine morphology of eroded surface.
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Slow-wave resonant structures in branch-line coupler miniaturization: a case study
PublikacjaA case study of novel slow-wave resonant structures dedicated to efficient microstrip branch-line coupler size reduction has been presented. A compact 3-dB branch-line coupler has been designed to mimic the performance of its conventional counterpart, simultaneously demonstrating a substantial 88% surface area reduction. The vital usefulness of the approach in the process of microstrip line abbreviation has been experimentally...
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Filtering EBG Structures Implemented in Coplanar Waveguide Feedline of Planar Slot Antenna
PublikacjaA novel compact dual-band slot antenna fed by a coplanar waveguide (CPW) incorporating electromagnetic band gap (EBG) structures has been proposed. At first, a classic wideband slot antenna fed by a CPW, dedicated to work in 2 ÷ 18 GHz band, has been designed. Subsequently, by adding simple EBG filtering structures into a CPW feedline, a dual-band performance ranging from 2.5 to 5.3 GHz and from 13.5 to 16.3 GHz, with the voltage...
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Influence of spatial structures of 316L stainless steel on its cavitation erosion resistance
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Shaking table experimental study on the effectiveness of polymer bearings for seismic isolation of structures
PublikacjaSeismic isolation has been recognised to be a very effective way of protecting structures from damage during earthquakes. It allows us to extend the natural period of the structure and therefore avoid resonance with the ground motion. Moreover, by increasing damping in the isolation devices, more energy can be dissipated and thus the structural response can be further reduced. The aim of this paper is to show the results of the...
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Guided wave propagation in structures. Modelling, experimental studies and application to damage detection
PublikacjaCelem niniejszej pracy są eksperymentalne i numeryczne analizy propagacji prowadzonych fal sprężystych w stalowych konstrukcjach prętowych, belkowych, ramowych, tarczowych i płytowych. W szczególności praca poświęcona jest: (a) modelowaniu propagacji fal z uwzględnieniem zjawiska dyspersji; (b) budowie modeli obliczeniowych w formalizmie metody elementów spektralnych; (c) eksperymentalnej weryfikacji zaproponowanych modeli; (d)...
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Structures for parameterization, meshing and data exchange of topologically related surfaces of a ship hull
PublikacjaThis paper presents proposal of data structures for storage and processing of a parametric three-dimensional model of a midship hull sections. The model consists of coarse surfaces like: decks, frames, girders, stiffeners, brackets, partitions etc. bounded by topological relations. All workshop details are omitted as the model is intended for numeric calculations. Proposed data structures are prepared to facilitate changes in the...
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Eficient multimode mixed time-frequency domain analysis and optimization of waveguide structures.
PublikacjaW pracy przedstawiona jest pełnofalowa analiza i optymalizacja struktur falowodowych o zadanej topologii. Nieciągłości falowodowe analizowane są z wykorzystaniem metody FDTD-IBC oraz scharakteryzowane uogólnioną macierzą rozproszenia. Efektywność metody zilustrowana jest na przykładzie filtru falowodowego siódmego rzędu.
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Production structures and strategies supporting lean parts manufacturing: an industrial case study.
PublikacjaPrzedstawiono model sformalizowanego opisu wzorców możliwości wytwarzania zróżnicowanego spektrum przedmiotów oraz analizy podobieństwa ich procesów technologicznych, dla kształtowania struktur przestrzennych systemów typu gniazdowego, z uwzględnieniem paradygmatu oszczędnej produkcji. Zaproponowano algorytm grupowania przedmiotów wg określonych, w postaci ciągów znakowych, sekwencji operacji procesu technologicznego oraz kryterium...
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Eficient multimode mixed time-frequency domain analysis and optimization of waveguide structures.
PublikacjaW pracy przedstawiona jest pełnofalowa analiza i optymalizacja struktur falowodowych o zadanej topologii. Nieciągłości falowodowe analizowane są z wykorzystaniem metody FDTD-IBC oraz scharakteryzowane uogólnioną macierzą rozproszenia. Efektywność metody zilustrowana jest na przykładzie filtru falowodowego siódmego rzędu.
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A review of stability problems of thin-walled structures developed at Gdańsk University of Technology
PublikacjaW pracy podano przegląd problemów stateczności konstrukcji cienkościennych, które były przedmiotem badań na Politechnice Gdańskiej. Przedstawiono bibliografię obejmującą 75 prace podzielone na trzy grupy tematyczne: stateczność prętów i łuków, pokrytyczne zachowanie się elemntów oraz optymalne projektowanie i analizę wrażliwości.