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1
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Conductivity and Superconductivity in Granular Materials

100%
Gazda M., Kusz B., Gackowska J., Sadowski W.
Acta Physica Polonica A
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2008
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vol. 114
|
issue 1
143-148
EN
Granular metals and superconductors are very interesting materials thanks to their untypical electrical properties caused by the presence of the Coulomb effects, electron and Cooper pair tunnelling and various aspects of disorder. Most typical and widely studied representatives of this group consist of low T_c superconductor granules distributed in insulating matrix (e.g. lead in germanium matrix). In comparison with them a system of granules of high-T_c superconductors embedded in an insulating matrix is more difficult to be experimentally realised. (Bi, Pb)-Sr-Ca-Cu-O materials obtained with solid state crystallisation method may be considered as an example of granular and disordered metals and superconductors. Solid state crystallisation of initially amorphous material leads to formation of 2201 and 2212 granules embedded in the insulating or semiconducting matrix. Further annealing causes increase in size and/or the number of conducting grains and decrease in the width of the insulating barriers between them. In both cases of low- and high-T_c granular materials the main parameters, which determine their properties, are the amount of metallic phases and the tunnelling conductivity between the neighbouring grains. In this work some properties of low- and high-T_c granular materials are discussed and compared.
2
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Three Point Bending Behavior of Woven Glass, Aramid and Carbon Fiber Reinforced Hybrid Composite Tube

80%
Ekşi S., Genel K.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-59-B-61
EN
In this study, bending behavior of hybrid composites reinforced by different type of fibers is investigated experimentally. In the preparation of composite samples with different number of layers having the same thickness and woven shaped glass, aramid and carbon fibers are used and three-point bending test is carried out to determine bending behavior. It is seen from the test results that, regardless of fiber type, the load bearing capacity and energy absorption capability are increased by increasing layer number. As a result of evaluation of hybrid composites containing different fibers with respect of load-carrying capability and energy absorbing capacity, aramid-fiber reinforced composite with 2 and 4 layer provides better performance. T+2GF+2CF+2AF specimen can be preferred in between 10 layered hybrid tubes and T+2GF+2AF+6CF and T+2GF+2CF+6AF specimens in 10 layered hybrid tubes. Load carrying capacity of hybrid tubes increased 7 times and energy absorbing capacity 9.6 times, respectively.
3
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Thermal Penetration of Gold Nanoparticles into Silicon Dioxide

80%
Ilkiv I., Kotlyar K., Amel'chuk D., Lebedev S., Cirlin G., Bouravleuv A.
Acta Physica Polonica A
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2017
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vol. 132
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issue 2
366-369
EN
We report on an experimental study of the thermal annealing processes under air and nitrogen atmospheres of colloidal Au nanoparticles deposited onto SiO₂/Si(100) samples. It was shown that Au nanoparticles during annealing under ambient conditions could penetrate inside silicon dioxide layers forming pores at that their lengths were found to be dependent on the annealing time. The influence of oxygen on the penetration process is discussed. At the same time, the annealing of Au nanoparticles under nitrogen conditions did not result in the formation of pores.
4
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Investigation of Thermal Properties of PUF/colored Organoclay Nanocomposites

80%
Gürses A., Doğar Ç., Köktepe S., Mindivan F., Güneş K., Aktürk S.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
979-983
EN
Recently PF resins can be also prepared by the addition of urea because urea accelerates cure process of PF resin, reduces the cost and improves its strength performance. Clays have long been used as inorganic fillers in polymer systems because of low cost, availability and improved thermal properties of resulting polymer composites. Clay nanocomposites of different types yield a marked increase in a number of properties of thermoplastic and other resins and composites. This study investigates the variation of thermal properties of PUF/colored organoclay nanocomposites with increased colored clay ratio. For this the DSC, XRD, FT-IR and HRTEM analyses were made. The XRD patterns and HRTEM images showed that clay platelets were exfoliated at the lower contents of organoclay, whereas at the higher content of organo clay tactoids were observed. The XRD analysis results implied that the amorphous behaviour increased with increased content of colored organoclay. The DSC thermograms indicated that glassy transition temperature (T_{g}) was increased, appearing prominent crystallization peaks at the lower ratios of organoclay. The T_{g} value was partially decreased and the peak intensities gradually decreased with increased content of clay. The thermogram for composite with clay content of 20% was similar to the thermogram of virgin resin. This can be attributed to the shifting of the textural structure for this composite from prominent crystalline structure to amorphous one.
5
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Polarimetric and Bragg Optical Fiber Sensors for Stress Distribution and Temperature Measurements in Composite Materials

80%
Lesiak P., Szeląg M., Mileńko K., Woliński T., Domański A., Jędrzejewski K., Boczkowska A.
Acta Physica Polonica A
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2011
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vol. 120
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issue 4
698-701
EN
Composite structures are made from two or more constituent materials with significantly different physical or chemical properties and they remain separate and distinct in a macroscopic level within the finished structure. This feature allows us for introducing an optical fiber sensors matrix into the composite material. These sensors can demonstrate stress distribution inside a tested material influenced by external tensions. Two types of the optical fiber sensors, placed into one fiber simultaneously, are used as s matrix structure. One of them is based on application of the Bragg grating structure written inside the core of the fiber. Longitudinal stress modifies changes parameters of the Bragg grating and in the same, spectral characteristics of the light transmitted through the fiber. The second one is based on application of highly birefringent fibers which under external stress introduce polarization changes in the output light. These sensors placed into one fiber give a possibility to the measure two external tensions separately.
6
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Structural Studies of C-Ni-Pd Nanocomposite Films Deposited on Al₂O₃ Substrate

80%
Kozłowski M., Czerwosz E., Sobczak K., Kurowska B.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1409-1412
EN
The properties of nanocomposite carbon-nickel-palladium (C-Ni-Pd) films deposited on Al₂O₃ substrate have been investigated and the results are presented in this work. C-Ni-Pd films were obtained by a 3 step process consisting of PVD/CVD/PVD methods. The structure and morphology of the obtained films were characterized by scanning electron microscopy and transmission electron microscopy techniques at various stages of film formation. Energy dispersive X-ray spectrometer was used for measuring the elements segregation in the obtained film. Transmission electron microscopy and scanning transmission electron microscopy observations have shown carbon nanotubes decorated with palladium nanoparticles in the final film. The average size of the palladium nanoparticles did not exceed 10 nm.
7
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The Influence of Substrate on Size of Pd Nanoparticles in C-Pd Composites Obtained in the PVD and CVD Processes

80%
Sobczak K., Kozłowski M., Czerwosz E.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1413-1416
EN
This paper presents the results of research of C-Pd composite films obtained by the physical vapor deposition and chemical vapor deposition method. These films will be applied as hydrogen sensors. It has been examined whether the substrate has an impact on morphology and topologies of the C-Pd composite and whether the thermal conductivity of the substrate has an impact on the average size of the Pd nanoparticles. Substrates such as Al₂O₃, SiO₂, Si, and Mo were used, and in the physical vapor deposition process fullerene (C₆₀) and palladium acetate were deposited. Some of the samples were examined microscopically, while another part was modified in the chemical vapor deposition process in the presence of xylene. It was found that the average size of the Pd nanoparticles prepared in the physical vapor deposition process is independent of the substrate for all of the substrates used in the present experiment. During the chemical vapor deposition process an increase of the size of the Pd nanoparticles was observed - as expected. What is more, we noticed a weak relation between the size of the Pd nanoparticles and the type of substrate on which the C-Pd composite was deposited.
8
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Influence of Angular Orientation of the Embedded Highly Birefringent Fiber on PMD Changes under Axial Stress

80%
Budaszewski D., Lesiak P., Plaga R., Rajan G., Semenova Y., Farrell G., Boczkowska A., Domański A., Woliński T.
Acta Physica Polonica A
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2011
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vol. 120
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issue 4
575-578
EN
In the paper we present results of the research on polarization mode dispersion changes inside the polarimetric optical fiber sensors based on highly birefringent optical fibers embedded into composite materials with different angular orientations of the optical axes. Based on measurements made for different types of highly birefringent optical fiber sensors we have shown that strain sensitivities after lamination process are different in comparison to the data obtained before lamination. Our results indicate that polarization mode dispersion in side-hole highly birefringent fibers under axial stress strongly depends on fiber orientation in the composite material suggesting that orientation of the polarization axes of the highly birefringent fiber can be responsible for behavior of the fiber inside the composite material.
9
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X-ray Diffraction of AuCl Semiconductor Nanocrystals Embedded in NaCl Single Crystals Grown by Czochralski Method

80%
Zehani F., Zaioune H.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
312-313
EN
The AuCl nanocrystals embedded in NaCl single crystals are elaborated using the Czochralski method. The X-ray diffraction has confirmed the formation of the AuCl nanocrystals with a tetragonal structure inside the NaCl matrix. The average radius of the AuCl nanocrystals is estimated using the Scherrer formula.
10
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Structural Study of Polyethylene/Montmorillonite Systems

80%
Malicka A., Domka L.
Acta Physica Polonica A
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2008
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vol. 114
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issue 2
423-431
EN
The effect of modification of montmorillonite (with 3-aminopropyltrimethoxysilane or hexadecyltrimethylammonium chloride) on the mechanical properties of the composites based on HDPE Hostalen ACP 5831 with the modified montmorillonite as filler, was studied. The structures of the fillers and nanocomposites were characterised by the scanning electron microscopy and X-ray diffraction study. The effect of the filler modification on the mechanical parameters of the nanocomposites and their structure was assessed on the basis of determination of the mechanical resistance, elongation at maximum tearing stress, bending strength, deformation at the maximum force and elasticity modulus on bending (three-point bending strength).
11
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Synthesis, Structure, and Catalytic Activity of Au/Poly(ethylene terephthalate) Composites

80%
Mashentseva A., Borgekov D., Zdorovets M., Russakova A.
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vol. 125
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issue 6
1263-1267
EN
A standard technique of electroless gold deposition was modified by changing the composition of Ag-based activation solution. This allows preparation of two types of poly(ethyleneterephthalate) (PET) track etched membranes coated entirely with gold after 1, 5, and 24 h of reaction at 4°C. After dissolving the polymer template, gold nanotubes with outer diameter of 70-80 nm were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. Reduction of p-nitrophenol to p-aminophenol by sodium borohydride was used to investigate the catalytic activity of as-prepared Au/PET membrane. All experiments were carried out for five consecutive cycles and rate constant of the pseudo-first-order reaction was calculated. It was found that Au/Ag/PET composites prepared after activation for 3 min in Ag-based solution (with potassium sodium tartrate as reducing agent) more effective catalyst (k=0.087 min^{-1}) was obtained when the Au/PET samples activated with ammonia silver nitrate solution (k=0.041 min^{-1}).
12
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Comparison of Bragg and Polarimetric Optical Fiber Sensors for Stress Monitoring in Composite Materials

80%
Domanski A., Lesiak P., Milenko K., Budaszewski D., Chychlowski M., Ertman S., Tefelska M., Wolinski T., Jedrzejewski K., Lewandowski L., Jasiewicz W., Helsztynski J., Boczkowska A.
Acta Physica Polonica A
|
2009
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vol. 116
|
issue 3
294-297
EN
Composite structures are made of two or more components with significantly different physical or chemical properties and they remain separate and distinct in a macroscopic level within the finished structure. This feature allows for introducing optical fiber sensors into the composite material. These sensors can demonstrate stress distribution inside tested material influenced by external tensions. Two types of the optical fiber sensors are used as the 3D structure. One of them is based on application of fiber Bragg grating inside the core of the fiber. Longitudinal stress changes parameters of the Bragg grating and simultaneously, spectral characteristics of the light transmitted through the fiber. The second one is based on application of highly birefringent fibers which, under external stress, introduce polarization changes of the output light.
13
Content available remote

Presence of Inductivity in (CoFeZr)_x(PZT)_{1-x} Nanocomposite Produced by Ion Beam Sputtering

80%
Kołtunowicz T., Żukowski P., Boiko O., Fedotov A., Larkin A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 5
853-856
EN
This paper presents the investigations of the electrical properties of the (CoFeZr)_{x}(PZT)_{1-x} nanocomposite with the metallic phase content x=43.8 at.%, which was produced by ion beam sputtering. Such preparation took place under an argon atmosphere with low oxygen content with its partial pressure P_{O₂} = 2×10¯³ Pa. The measurements were performed using alternating current within the frequency range of 50 Hz-10⁵ Hz for measuring temperatures ranging from 238 K to 328 K. The (CoFeZr)_{43.8}(PZT)_{56.2} nanocomposite sample subjected to a 15 min annealing process in air at the temperature Tₐ=423 K demonstrates a phase angle of -90° ≤ θ ≤ 0° in the frequency range 50 Hz-10⁵ Hz. It corresponds to the capacitive type of conduction. In the frequency range 10⁴-10⁵ Hz sharp minima in selected conductivity vs. frequency characteristics occur, which corresponds to a current resonance phenomenon in RLC circuits. In case of a sample annealed at Tₐ=498 K the inductive type of conduction with 0° ≤ θ ≤ +90° occurs in a high frequency area. At the frequency f_{r} characterized by the phase angle θ = 0°, the capacity value reaches its local minimum. It indicates a voltage resonance phenomenon in conventional RLC circuits. The θ = +90° crossing in the frequency dependence of phase angle corresponds to the current resonance phenomenon, which is represented by a strong local minimum in the conductivity vs. frequency characteristics.
14
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Temperature Dependent Catalytic Activity of Ag/PET Ion-Track Membranes Composites

80%
Borgekov D., Mashentseva A., Kislitsin S., Kozlovskiy A., Russakova A., Zdorovets M.
Acta Physica Polonica A
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2015
|
vol. 128
|
issue 5
871-874
EN
Electroless deposition has been used to coat finely porous polyethylene terephthalate (PET) track-etched membranes with silver, forming silver nanotubes within the pores with inner and outer diameters of 60 and 100 nm. The sample's X-ray diffraction pattern shows a face-centered cubic crystalline phase of silver with the lattice constant 4.0838 nm. The average size of silver nanoclusters, as obtained from the scanning electron microscopy analysis is about 30 nm which is consistent with the X-ray diffraction results. The temperature dependent catalytic activity of prepared composites is demonstrated for two model reactions such as reduction of 4-nitrophenol (4-NP) and decomposition of hydrogen peroxide. Apparent constant rates and activation energy as well as reusability of catalysts were determined. The developed composite catalyst could be used consecutively for several runs without any damages for 4-NP reduction. For hydrogen peroxide reaction decomposition the reaction rate of the second cycle is reduced 2.4 times. Moreover, the second reuse reduced conversion of H₂O₂ to 54.7% suggests removal of active Ag centers during the first cycle of testing.
15
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Annealing of (CoFeZr)_{x}(CaF_2)_{100-x} Nanocomposites Produced by the Ion-Beam Sputtering in the Ar and O_2 Ambient

80%
Kołtunowicz T., Zhukowski P., Bondariev V., Fedotova J., Fedotov A.
Acta Physica Polonica A
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2013
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vol. 123
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issue 5
932-934
EN
This paper presents the investigations of electrical properties and effect of annealing on conductivity of (CoFeZr)_{x}(CaF_2)_{100-x} nanocomposites produced by ion-beam sputtering in the Ar and O_2 ambient. Investigations into conductivity of (CoFeZr)_{x}(CaF_2)_{100-x} nanocomposites depending on the measuring temperature and the annealing temperature have been performed. The application of a combined argon-oxygen beam brings about lowering of the potential barrier on the surface of nanoparticles. In the course of annealing the additional oxidation occurs. First it proceeds on the surface and then all through the metallic-phase particles.
16
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Influence of Al₂O₃ Particles Weight Fraction on Fracture Mechanism of AZ61 Mg-Al₂O₃ System Studied by In Situ Tensile Test in SEM

80%
Besterci M., Nagy Š., Huang S., Velgosová O., Sülleiová K., Lin P.
Acta Physica Polonica A
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2016
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vol. 129
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issue 1
138-141
EN
In situ observation of AZ61 Mg alloy with 1 and 5 wt% of Al₂O₃ in the scanning electron microscopy was performed to study influence of the weight fraction of Al₂O₃ particles on the deformation and fracture mechanism during tensile test. Structure of the experimental materials was also analysed; microstructures were heterogeneous, with randomly distributed globular Al₂O₃ particles (average diameter of 25 nm) and Mg₁₇Al₁₂ intermetallic phase (average diameter of 0.4 μ m). It was shown that during tensile deformation the failure of Mg₁₇Al₁₂ particles and decohesion of the matrix-Al₂O₃ particles interphase boundary started simultaneously. Decohesion resulted from the different physical properties of matrix and Al₂O₃ particles. The influence of the Al₂O₃ weight fraction on the final fracture was evident; for material with 5 wt% of Al₂O₃, the fracture surface was approximately perpendicular to the loading direction and for material with 1 wt% of Al₂O₃ was at 45° angle. Fracture surface had transcrystalline ductile character.
17
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Voltage and Current Resonance in Nanocomposite (FeCoZr)_x(CaF₂)_{100-x} Produced by Ion-Beam Sputtering in Pure Argon Atmosphere

80%
Koltunowicz T., Zukowski P., Bondariev V., Fedotov A., Svito I., Fedotova J., Saad A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 5
897-900
EN
In this paper the results of investigations of electrical properties of metal-dielectric nanocomposites (FeCoZr)_x(CaF₂)_{100-x} are presented. The samples with the metallic phase content x=45.7 at.% were produced by ion-beam sputtering method in pure argon atmosphere, and subsequently annealed at 398 K for 15 min. The measurements of electrical properties were performed in the frequency range from 50 Hz to 1 MHz. The frequency dependences of phase angle θ, capacity C_{p}, conductivity σ and dielectric loss factor tanδ were measured at seven different temperatures ranging from 148 K to 263 K. It was found that the nanocomposite exhibits the phenomena of voltage resonance and current resonance, characteristic of the conventional RLC circuits with series and parallel connections of elements.
18
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A Novel High Strain Rate Sensitive Rigid Polyurethane Resin Based Syntactic Foam

80%
Yazıcı M.
|
EN
Syntactic foams are closed cell structured foam materials and present improved properties for lightweight and high performance material requests. They have been widely used in naval, aeronautical, aerospace, civil, industrial, and automotive engineering applications on account of their good acoustical attenuation, excellent strength to weight ratio, vibration isolation, dielectric properties. In this study, a novel high strain rate sensitive syntactic foam was developed. A rigid polyurethane resin was used as a binder material. Glass bubbles were used as an additive for producing cell structure. Elastomeric silicone rubber resin were used to change elastic properties of the foam as an additional binder material. Quasistatic compression properties and high strain rate compression properties were obtained by using Instron Universal Tensile-Compression Machine and Split Hopkinson Pressure Bar experimental setup respectively. The results show that developed foams are low dense and very high strain rate sensitive materials. Consequently, developed foam can be used for the blast, impact or ballistic mitigation purpose as a coating material.
19
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Dielectric Properties of (CoFeZr)_x(PZT)_{100-x} Nanocomposites Produced with a Beam of Argon and Oxygen Ions

80%
Koltunowicz T.
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vol. 125
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issue 6
1412-1415
EN
In this paper it was established that nanocomposite (FeCoZr)_x(PZT)_{100-x}, with x=90.0 at.%, produced by ion sputtering with argon and oxygen beam remains under the percolation threshold. It is related to the compound structure of films and creation of coat consisting of metallic oxides on surface of metallic phase nanogranules, which prevents electric contact between nanoparticles. Verification of the Arrhenius dependences for capacity and conductivity demonstrates that dominant part of metallic phase nanogranules has metal oxide coatings. Only a small number of nanogranules (probably around a few percent) does not have oxide coating.
20
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[100] Loading of Fcc Based Nanofibre Reinforced Composites

71%
Černý M., Pokluda J.
Acta Physica Polonica A
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2012
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vol. 122
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issue 3
505-508
EN
Ab initio calculations of theoretical tensile and compressive strengths in the 〈100〉 direction of a composite having continuous nanofibre reinforcements are performed using pseudopotential approach within density functional theory. Results for iridium or platinum nanofibres in copper or gold matrices, presented as case studies, reveal that the theoretical tensile and compressive strengths almost linearly increase with increasing atomic concentration of the reinforcement exhibiting only slight positive strength deviations from the linearity for Pt-Au and slight negative deviations of the tensile strength for Ir-Cu.
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