Search results for: beam
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Weak Solutions within the Gradient-Incomplete Strain-Gradient Elasticity
PublicationIn this paper we consider existence and uniqueness of the three-dimensional static boundary-value problems in the framework of so-called gradient-incomplete strain-gradient elasticity. We call the strain-gradient elasticity model gradient-incomplete such model where the considered strain energy density depends on displacements and only on some specific partial derivatives of displacements of first- and second-order. Such models...
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How Do Ionic Liquids Affect the Surface Structure of Titania Photocatalyst? An Electron-Trap Distribution-Analysis Study
PublicationTitanium(IV) oxide, titania, photocatalyst particles were prepared from titanium alkoxide in the presence of several kinds of ionic liquids, and it was clarified that a group of samples exhibited photocatalytic activity for phenol degradation under the irradiation of light of wavelength >400 nm higher than those of the other group of samples. Although the conventional structural analytical results could not be related to the activity,...
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Implementation of Hermite-Ritz method and Navier’s Technique for Vibration of Functionally Graded Porous Nanobeam Embedded in Winkler-Pasternak Elastic Foundation Using bi-Helmholtz type of nonlocal elasticity
PublicationPresent study is devoted to investigating the vibration characteristics of Functionally Graded (FG) porous nanobeam embedded in an elastic substrate of Winkler-Pasternak type. Classical beam theory (CBT) or Euler-Bernoulli beam theory (EBT) has been incorporated to address the displacement of the FG nanobeam. Bi-Helmholtz type of nonlocal elasticity is being used to capture the small scale effect of the FG nanobeam. Further, the...
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Experimental Study on the Effectiveness of Polyurethane Flexible Adhesive in Reduction of Structural Vibrations
PublicationThe aim of the present study is to consider the idea of using polyurethane flexible adhesive in to reduce the vibrations in structures exposed to dynamic loads and evaluate their damping properties in relation to large deformations. Firstly, two aluminium cantilever beams, simulating structural elements (without and with polyurethane layer in the form of tape), were analysed, in order to check the damping of the unconstrained polymer...
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Mechanical Properties and Residual Stress Measurements of Grade IV Titanium and Ti-6Al-4V and Ti-13Nb-13Zr Titanium Alloys after Laser Treatment
PublicationNowadays, surface engineering focuses on research into materials for medical applications. Titanium and its alloys are prominent, especially Ti-6Al-4V and Ti-13Nb-13Zr. Samples made of pure grade IV titanium and the titanium alloys Ti-6Al-4V and Ti-13Nb-13Zr were modified via laser treatment with laser beam frequency f = 25 Hz and laser beam power P = 1000 W during a laser pulse with duration t = 1 ms. Subsequently, to analyze...
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Maciej Matciak doktor
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Pomiary grubości cienkich warstw metodą modulacji chromatycznej.
PublicationTematem artykułu jest pomiar grubości struktur cienkowarstwowych szerokostosowanych w optoelektronice, transparentnych warstw dielektrycznych. Grubość jest najistotniejszym parametrem warstwy i determinuje jej właściwościoptyczne. Metoda pomiaru grubości cienkich warstw powinna być bezkontaktowa, nieniszcząca, niekosztowna oraz odporna na zakłócenia
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Scanning electrochemical micrographs of poly(lactic acid) 3D printed electrodes ablated by femtosecond laser
Open Research DataThe dataset contains the scanning electrochemical micrographs of the femtosecond laser (FSL) ablation at the surface of commercially available carbon black-filled poly(lactic acid) 3D printed electrode. The process is used for the increase of the charge transfer of this electrode in electrochemical studies.
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Microstructure of barium-vanadate glasses
Open Research DataThe structure of barium-vanadate glasses was measured by SEM and XRD techniques. Samples of the composition of xBaO-(100-x)V2O5 where x= 30, 40 and 45 (in %mol) were prepared by the conventional melt quenching technique. Appropriate amounts of reagents: BaO (≥99.9%, P.P.H STANLAB Sp.J.) and V2O5 (≥99.9%, POCH) were thoroughly mixed in an agate mortar....
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Morphology and structure of ammonium vanadates synthesis by hydrothermal method
Open Research DataThe DataSet contains the XRD patterns, FTIR spectra, and scanning electron microscopy (SEM) micrographs of ammonium vanadates synthesis by hydrothermal method from different NH4VO3 precursors. The results reveal that a mixture of (NH4)V4O10xH2O and(NH4)0.76V4O10 was obtained for both precursors, however the contribution of each phase was different for...
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Sensitivity analysis of a composite footbridge
PublicationThis work include an example of sensitivity analysis for the design of a composite footbridge. A sandwich structure is used, consisting two high-strength skins separated by a core material. The analysis was conducted for two numerical models. The first one is a simple, single-span beam of a composite cross-section (laminate and foam), with different Young’s modulus for each material. Calculations were made by means of a MATLAB-based...
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Development and application of asphalt binder relaxation test in different dynamic shear rheometers
PublicationIn this study, a novel relaxation test is proposed to evaluate asphalt binder low temperature properties using a Dynamic Shear Rheometer (DSR) with parallel plates of 4 mm in diameter. Three rheometers from three different manufacturers are used to analyze seven asphalt binders. Different material parameters are derived which are useful to evaluate and discriminate different asphalt binders. Test results of all three instruments...
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CFGFRPT Piles with a Circular Cross-Section and their Application in Offshore Structures
PublicationThe possibilities of using concrete piles in a polymer composite reinforced with glass fibres in offshore facilities were shown. Laboratory tests of CFGFRPT type piles compressed axially and in eccentric compression for the analysis of CFGFRPT piles were used. Methods of analysis of dynamic systems for mathematical modelling of the displacement of the hammer in the pile driving process were applied. The possibilities of combining...
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Two tests for adhesive bonding long term characterization: principles and applications
PublicationThis article describes recent refinement of the traditional wedge test technique used to characterize durability of the adhesive joints. We propose two types of measuring protocols to monitor precisely and continuously the propagation of an "effective" crack during long term mode I fracture mechanic test. First method is directly derived from the traditional wedge test technique and consist in monitoring the surface strain of adherent...
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The modelling method of discrete-continuous systems
PublicationThe paper introduces a method of discrete-continuous systems modelling. In the proposed method a three-dimensional system is divided into finite elements in only two directions, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of partial differential equations. General difference equations of discrete system are obtained using the rigid finite element method. The limit...
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Stability of a truss under upward wind loading
PublicationThe present paper is devoted to the numerical investigations of stability of a truss under upward wind load. The truss is braced at its the upper cord. A structural variant including lateral braces, or lateral and torsional braces is considered. The research presents the problems of linear buckling and non-linear static analysis of the truss shell and beam model with geometric and material non-linearity are presented. The initial...
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Modal analysis of temporary steel grandstand equipped with different bracing systems
PublicationThe aim of this paper is to present the results of numerical analysis focused on temporary steel scaffolding grandstand. The investigation has been devoted to modal analysis where modes of free vibrations and corresponding natural frequencies have been estimated and compared. The structure was equipped with different types of stiffener members. One on them is a typical tubular stiffener, while the second one is spe-cially designed...
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As- built inventory of the office building with the use of terrestrial laser scanning
PublicationTerrestrial Laser Scanning (TLS) is an efficient tool for building inventories. Based on the red- laser beam technology it is possible to provide the high accuracy data with complete spatial information about a scanned object. In this article, authors present the solution of use a TLS in as-built inventory of the office building. Based on the provided data, it is possible to evaluate the correctness of built details of a building...
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Free Vibration of Flexomagnetic Nanostructured Tubes Based on Stress-driven Nonlocal Elasticity
PublicationA framework for the flexomagneticity influence is here considered extending the studies about this aspect on the small scale actuators. The developed model accommodates and composes linear Lagrangian strains, Euler-Bernoulli beam approach as well as an extended case of Hamilton’s principle. The nanostructured tube should subsume and incorporate size effect; however, for the sake of avoiding the staggering costs of experiments,...
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Influence of Dielectric Overlay Permittivity on Size and Performance of Miniaturized ESPAR Antenna
PublicationIn this paper, influence of dielectric overlay permittivity on miniaturized ESPAR antenna parameters is presented. ESPAR antenna is a low-cost and energy-efficient way to implement beam steering capability to a node and improve network performance. The antenna size reduction is obtained by embedding its active and passive elements in ABS based materials of relative permittivity equal to 4, 5.5 and 7.5 in order to achieve network...
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Nonlinear strain gradient and micromorphic one-dimensional elastic continua: Comparison through strong ellipticity conditions
PublicationWe discuss the strong ellipticity (SE) conditions for strain gradient and micromorphic continua considering them as an enhancement of a simple nonlinearly elastic material called in the following primary material. Recently both models are widely used for description of material behavior of beam-lattice metamaterials which may possess various types of material instabilities. We analyze how a possible loss of SE results in the behavior...
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On time-dependent nonlinear dynamic response of micro-elastic solids
PublicationA new approach to the mechanical response of micro-mechanic problems is presented using the modified couple stress theory. This model captured micro-turns due to micro-particles' rotations which could be essential for microstructural materials and/or at small scales. In a micro media based on the small rotations, sub-particles can also turn except the whole domain rotation. However, this framework is competent for a static medium....
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On a 3D material modelling of smart nanocomposite structures
PublicationSmart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity...
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Improved jamming resistance using electronically steerable parasitic antenna radiator
PublicationThis paper presents an idea of using an Electronically Steerable Parasitic Antenna Radiator (ESPAR) for jamming suppression in IEEE 802.11b networks. Jamming (intentional interference) attacks are known to be effective and easy to perform, which may impose connectivity problems in applications concerning Internet of Things (IoT). In our paper, theoretical considerations are presented and the results of experiments performed in...
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Flexural buckling and post-buckling of columns made of aluminium alloy
PublicationThe paper concerns flexural buckling and initial post-buckling of axially compressed columns made of aluminium alloy described by the Ramberg-Osgood relationship. The non-linear differential equation of the problem is derived using the stationary total energy principle and the assumptions of classical beam theory within a finite range. The approximate analytical solution of the equation leading to the buckling loads and initial...
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Electron attachment to hexafluoropropylene oxide (HFPO)
PublicationWe probe the electron attachment in hexafluoropropylene oxide (HFPO), C3F6O, a gas widely used in plasma technologies. We determine the absolute electron attachment cross section using two completely different experimental approaches: (i) a crossed-beam experiment at single collision conditions (local pressures of 5 × 10−4 mbar) and (ii) a pulsed Townsend experiment at pressures of 20–100 mbar. In the latter method, the cross sections...
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generation of the vorticity mode by sound in a bingham plastic
PublicationThis study investigates interaction between acoustic and non-acoustic modes, such as vorticity mode,in some class of a non-newtonian fluid called Bingham plastic. The instantaneous equations describinginteraction between different modes are derived. The attention is paid to the nonlinear effects in the fieldof intense sound. The resulting equations which describe dynamics of both sound and the vorticity modeapply to both periodic...
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An influence of the ship's block coefficient implementation on the evaluation of it's hull girder bending
PublicationAn influence of the three different ways of implementation ship's block coefficient δ (three geometrical models) on the stresses due to wave bending moment have been investigated. Two models have been applied and compared: beam one (description of the shape usingparameters) and FEM shell model (direct representation of the shape). The outcomes have been compared to Polish Register of Shipping (PRS) rules. The results show that...
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Local buckling of compressed flange of cold-formed channel members made of aluminum alloy
PublicationThe paper deals with local buckling of a compressed single flange of thin-walled channel cold- formed columns and beams made of aluminum alloy. Material is described by means of the Ramberg-Osgood constitutive equation. Axial compression of the columns and beams undergoing bending is taken into consid- eration. A simple model of the member flange in the form a long beam elastically connected to the web is used to find the critical...
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Buckling and initial post-local buckling behaviour of cold-formed channel member flange
PublicationThe initial post-buckling behaviour of a cold-formed channel member flange after its local buckling is investigated. An axially compressed column or beam subjected to pure bending is considered. The member material is assumed to follow a linear stress-strain relationship. The governing non-linear differential equation of the problem is derived using the minimum total potential energy principle. An approximate solution for the equation...
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Dissociative electron attachment to benzoic acid (C7H6O2)
PublicationThe dissociative electron attachment (DEA) to benzoic acid (C6H5COOH) has been studied using an experimental crossed beam setup of a quadrupole mass spectrometer and a trochoidal electron monochromator. Relative partial cross sections for the DEA to produce negative ion fragments show the main channels for dissociation. The comparison of the present results with the ultraviolet photoelectron spectrum of benzoic acid [J. Meeks,...
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The topography of Bi2VO5.5 ceramic measured with SEM and confocal microscope
Open Research DataThe topography of Bi2VO5.5 ceramics was measured by SEM and confocal microscope.
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Dyskretno-ciągła metoda modelowania układów dynamicznych
PublicationW artykule przedstawiono oryginalną metodę modelowania układów dyskretno-ciągłych. Metoda polega na dyskretyzowaniu układu trójwymiarowego jedynie w dwóch wybranych kierunkach. W trzecim z kierunków układ pozostaje ciągły. Otrzymany w ten sposób model jest modelem dyskretno-ciągłym. Opisany jest za pomocą równań różniczkowych cząstkowych. Ogólne równania różnicowe układu dyskretnego otrzymano, wykorzystując metodę sztywnych elementów...
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Wizyjny system monitoringu stanu nakładek stykowych odbieraków prądu
PublicationEksploatowane do niedawna w Polsce nakładki pantografów kolejowych były wykonywane w postaci styków miedzianych. Na początku 2011 r. przeprowadzono kompleksową zmianę typu nakładek stykowych, stosowanych przez operatorów korzystających z infrastruktury PKP PLK S.A., z miedzianych na metalizowane węglowe. Wraz z wprowadzeniem nakładek węglowych istnieje potrzeba opracowania nowych metod diagnostyki tego istotnego elementu toru zasilania...
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Measurements of photoionization of mercury atoms into the 6s 2S1/2, 5d96s2 2D5/2 and 5d96s2 2D3/2 ionic states over the energy range from 10.5 eV to 18.7 eV
PublicationPhotoionization of mercury atoms into the three lowest ionic states, 5d106s 2S1/2, 5d96s2 2D5/2 and 5d96s2 2D3/2 has been studied in the photon energy ranges from their respective thresholds to 18.7 eV. The photoionization spectra were obtained with high energy resolution at an angle of 0° with respect to the polarization vector of the photon beam. The high energy resolution and sensitivity achieved in the measurements permitted...
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Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning
PublicationThe paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation...
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A DISCRETE-CONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublicationThe paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described...
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Adhesive compliance effect in mode I separation:Profilometry approach
PublicationThe effect of adhesive compliance on the deflection of a loaded, bonded beam was studied using laser profilometry. Experimental data obtained were compared with both Euler-Bernoulli (encastré) and Winkler (one parameter elastic foundation) models. A third, analytical, 2D model, based on shear within the adhesive layer (two parameter elastic foundation), was introduced. Finite element analysis (FEA) was also used to study the effect...
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Formation and Growth of the Crack in Bonded Joints Under Mode I Fracture: Substrate Deflection at Crack Vicinity
PublicationAdhesive bonding is now commonly used in aircraft, cars, boats, etc. In these applications, thin panels are often bonded. In such thin structures, heterogeneous mechanical loading along the bondline edge (or potential crack front), is likely to arise due to 3D structural effects. The crack front and its vicinity is a special region, in that it is where structural properties of the adherend material meet those of the adhesive (discontinuity)....
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Numerical analysis of a temporary steel grandstand
PublicationThe purpose of this paper is to present the results of the numerical analysis focused on the response of the temporary steel scaffolding grandstand subjected to human-induced vibrations due to jumping. Shell as well as beam elements have been used in the numerical model. Its first stage has involved conducting modal analysis in order to determine the modes of free vibrations and the corresponding natural frequencies for the empty...
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Verification of ESPAR Antennas Performance in the Simple and Calibration Free Localization System
PublicationThis paper presents the results of simulations and measurements of an indoor localization system that uses Electronically Steerable Parasitic Array Radiator (ESPAR) antennas with switched directional beam. Proposed antennas are dedicated for 2.4GHz ISM low-cost applications where determination of the incoming signal is required. The antennas performance is analyzed and verified with relation to positioning methods based on the...
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Vibro-Electrical Behavior of a Viscoelastic Piezo-Nanowire in an Elastic Substrate Considering Stress Nonlocality and Microstructural Size-Dependent Effects
PublicationThis research deals with dynamics response of a Pol/BaTiO3 nanowire including viscosity influences. The wire is also impressed by a longitudinal electric field. Hamilton's principle and Lagrangian strains are employed in conjunction with a refined higher-order beam theory in order to derive equations of motion. By combining nonlocality and small size...
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The role of low-energy electrons in the charging process of LISA test masses
PublicationThe estimate of the total electron yield is fundamental for our understanding of the test-mass charging associated with cosmic rays in the Laser Interferometer Space Antenna (LISA) Pathfinder mission and in the forthcoming gravitational wave observatory LISA. To unveil the role of low energy electrons in this process owing to galactic and solar energetic particle events, in this work we study the interaction of keV and sub-keV...
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Combination of terrestrial laser scanning and UAV photogrammetry for 3D modelling and degradation assessment of heritage building based on a lighting analysis: case study—St. Adalbert Church in Gdansk, Poland
PublicationThe construction of the St. Adalbert Church in Gdansk dates to 1310. It is a church of rich history and great historical value, and its care is challenging. In this study, the combination of unmanned aerial vehicle (UAV) photogrammetry and terrestrial laser scanning (TLS) was used to accurately build a 3D model of the church. Together with the collected historical inventory documentation, the historic building information model...
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Properties of Barium Cerate-Zirconate Thin Films
PublicationIn this work, we review several experimental results showing the electrical properties of barium cerate-zirconate thin films and discuss them in view of the possible influence of various factors on their properties. Most of the presented Ba(Ce, Zr, Y)O3 thin films were formed by the pulsed laser deposition (PLD) technique, however thin films prepared using other methods, like RF magnetron sputtering, electron-beam deposition, powder...
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Buckling of simplified models of silo with corrugated walls and vertical stiffeners
PublicationThe paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to...
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The structure of 70(2Bi2O3-V2O5) - 30SrBO7 measured with X-ray diffraction and SEM methods
Open Research DataThe structure changes of 70(2Bi2O3-V2O5)-30SrB4O7 glass occurred during increase in temperature was measured by XRD and SEM.
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Topography and microstructure of phosphate-iron glasses containing niobium and titanium
Open Research DataThe topography and microstructure of phosphate-iron glasses containing niobium and titanium were investigated by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM). Glass samples of the composition of 35P2O5-30Fe2O3-(35-x)Nb2O5-xTiO2 where x= 0; 7.5 and 15 (in %mol) were prepared by the conventional melt quenching technique. Appropriate...
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Examples of AFM applications in liquid environment
Open Research DataImportant advantage of atomic force microscopy (also tunneling microscopy) is the ability to work in different environments (vacuum, controlled atmosphere, liquid environment). The last one, open interesting possibilities, such as imaging of delicate biological materials in their natural state. The use of electrochemical mode allows for the modification...
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UWB Microstrip Antennas on a Cylindrical Surfaces
PublicationConformal antennas are becoming popular due to their many advantages and possibilities of applications they offer. The advantages of using antennas with a curved surface arise not only from the possibility of integrating them with the object on which they are mounted on but also from the increase, relatively to planar antennas, of their visible angular range. The circular antenna arrays, or arrays of radiators located on the surface...