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1

Wpływ stosunku wodno-cementowego na właściwości elektryczne wielofunkcyjnych kompozytów cementowych

Frąc Maksymilian, Szołdra Paulina, Pichór Waldemar

Cement Wapno Beton

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2025

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R. 30, nr 1

57--74

PL

W niniejszej pracy przedstawiono wyniki badań dotyczących wpływu stosunku wodno-cementowego [w/c] na właściwości elektryczne kompozytów cementowych z grafitem ekspandowanym [EG]. Analizie poddano próbki zawierające od 2% do 6% EG, przy stosunkach w/c w zakresie od 0,40 do 0,60. Badania obejmowały pomiary rezystywności metodą czteropunktową, spektroskopię impedancyjną, a także ocenę właściwości termoelektrycznych i samonagrzewających kompozytów. Uzyskane wyniki wskazują, że zwiększenie stosunku w/c prowadzi do obniżenia przewodnictwa elektrycznego badanych kompozytów, niezależnie od zawartości dodatku EG. Analiza widm impedancyjnych wykazała, iż w rozpatrywanym zakresie w/c, próg perkolacji zostaje przekroczony w przypadku kompozytów zawierających powyżej 4% EG. Im wyższa zawartość EG tym przy wyższym w/c próg perkolacji jest przekroczony. Istotną obserwacją jest kształt widma Nyquista dla kompozytów znajdujących się w zakresie perkolacji - słabo wykształcone półokręgi. Im bliżej progu perkolacji znajduje się kompozyt, tym mniej wyraźnie wykształcony jest półokrąg. Taki charakterystyczny kształt widma umożliwia określenie zawartości dodatku przewodzącego w zakresie perkolacji. Dodatkowo, wyniki badań potwierdzają wpływ stosunku w/c na właściwości samonagrzewające analizowanych kompozytów cementowych. Natomiast w/c wydaje się nie wpływa na wartość współczynnika Seebecka powyżej progu perkolacji. Uzyskane rezultaty jednoznacznie wskazują na istotną rolę zarówno stosunku wodno-cementowego w kształtowaniu właściwości funkcjonalnych tych materiałów.

EN

This study presents the results of research on the influence of the water-to-cement ratio [w/c] on the electrical properties of cement composites with expanded graphite [EG]. The analysis was conducted on samples containing 2 % to 6 % EG, with w/c ratios ranging from 0.40 to 0.60. The experimental program included four-point probe resistivity measurements, impedance spectroscopy, as well as evaluation of the thermoelectric and self-heating properties of the composites. The results indicate that increasing the w/c ratio leads to a reduction in the electrical conductivity of the studied composites, regardless of the EG content. Impedance spectra analysis showed that, within the investigated w/c range, the percolation threshold is exceeded in composites containing more than 4 % EG. The higher the EG content, percolation threshold is exceeded at higher w/c. An important observation is weakly formed semicircles in Nyquist plot for composites in the percolation zone. The closer conductivity of the composite is to the percolation threshold, the less distinct the semicircle. This characteristic spectrum shape allows for the determination of the conductive additive content in the percolation zone. Furthermore, the findings confirm that the w/c ratio significantly influences the self-heating properties of the investigated cement composites. In contrast, the w/c ratio does not appear to affect the magnitude of the Seebeck coefficient above the percolation threshold. The obtained results clearly indicate the significant role of water-to-cement ratio in shaping the functional properties of these materials.

2

Effect of Fe2O3 doping on the electrical and microstructural properties of ZnO-( Bi2O3, Sb2O3) varistor ceramics

Kharchouche Faiçal, Zebar Abdelkrim

Przegląd Elektrotechniczny

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2024

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R. 100, nr 4

192--197

EN

This study will allow us to see the effect of Fe2O3 doping on the electrical and microstructural properties of the ceramic varistor based on (Bi2O3, Sb2O3). The study deals with a ZnO-based varistor, containing, 0.5 mol% of (Bi2O3, Sb2O3) doped with 1 mol%, 2 mol%, and 4 mol% of Fe2O3. The ceramics samples were developed using the conventional route of the oxides mixture, sintered all the samples at 1000 °C. The mean grain size increased with the increase of the Fe2O3 amount and the grains were homogeneous, the varistors exhibited the relative density, the dielectric constant (ε′), dielectric dissipation factor (tanδ) and leakage current (IL) was increased with the increase of the Fe2O3 amount, Therefore, the nonlinearity coefficient (α) decreases from 23.58 to 8.61 and the breakdown field (Eb1mA) decreased from 341.41 to 202.01V/mm with an increase in the amount of Fe2O3.

PL

Badania te pozwolą nam zobaczyć wpływ domieszkowania Fe2O3 na właściwości elektryczne i mikrostrukturalne warystora ceramicznego na bazie (Bi2O3, Sb2O3). Badania dotyczyły warystora na bazie ZnO, zawierającego 0,5% mol (Bi2O3, Sb2O3) domieszkowanego 1% mol, 2% mol i 4% mol Fe2O3. Próbki ceramiki opracowano konwencjonalną drogą mieszaniny tlenków, wszystkie próbki spiekano w temperaturze 1000°C. Wraz ze wzrostem zawartości Fe2O3 zwiększała się średnia wielkość ziaren i ziarna były jednorodne, warystory wykazywały gęstość względną, wraz ze wzrostem zwiększała się stała dielektryczna (ε′), współczynnik rozproszenia dielektrycznego (tanδ) i prąd upływu (IL). ilości Fe2O3, zatem współczynnik nieliniowości (α) maleje z 23,58 do 8,61, a pole przebicia (Eb1mA) zmniejsza się z 341,41 do 202,01V/mm wraz ze wzrostem ilości Fe2O3.

3

Effесt of Chеmiсаl Cоmposition оn thе Miсrоstruсture, Hаrdnеss, аnd Elесtrical Conductivity Profiles of the Bi-Gе-X (Gа, Cu, Zn) Allоys

Djordjević A., Zečević Milena, Minić Dusco, Kolarević Milan, Manasijević Dragan, Ristić Vladica

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 3

891--902

EN

The miсrоstruсture, hаrdnеss, аnd elесtrical соnductivity of the alloys from tеrnаry systеms bаsed on Bi and Gе hаve nоt been studied so fаr. This pаper prеsents the rеsults of experimental and anаlytical investigation of Bi-Cu-Gе, Bi-Ga-Gе, and Bi-Gе-Zn ternary systems. Following experimental techniques were applied: optical microscopy (LOM), scаnning еlесtron miсrosсоpy (SEM) with enеrgy dispersivе spесtrometry (EDS), X-rаy diffrасtometric anаlysis (XRD), Brinеll hаrdness measurements and electrical conductivity mеаsurements. Among the analytical methods, the Cаlphаd mеthod and the software Pandаt ver. 8.1 were used. In all three investigated ternary systems an isothermal section at 25°C was selected for experimental testing. Based on the optimized thermodynamic parameters for the constitutive binary systems, the calculation was performed. The experimentally obtained results were compared with the results of thermodynamic calculations and gооd agreement wаs noticed. Also, in all three tested systems hardness and electrical conductivity were measured and using appropriate mathematical models these properties were guided in the entire range of the composition. The obtained results include determination of isothermal sections, identification of co-existing phases, electrical conductivity and hardness measurements and development of mathematical models for prediction of electrical conductivity and hardness.

4

Impact of sintering time on structure and electrical properties of Pb-free BNT-BKT-SZ ceramics

Manotham S., Butnoi P., Khieokae M., Paengchit P., Prajansri P.

Archives of Materials Science and Engineering

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2024

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Vol. 126, nr 2

49--57

EN

Purpose: The work focuses on preparing and characterising BNT-based ceramics via a solid-state method. To investigate the phase, microstructure, and physical and electrical properties of BNT-based ceramics. Design/methodology/approach: Lead-free piezoelectric bismuth sodium titanate – bismuth potassium titanate – stronsium zirconate (BNT-BKT-SZ) ceramics were fabricated by the solid-state reaction method. The effect of sintering temperature with soaking times of 2, 4, and 6 h at 1150°C on structural, microstructure, density, porosity, and electrical properties was examined. The phase formation of the ceramics was examined using X-ray diffraction (XRD). Scanning electron microscopy (SEM) (JEOL JSM5910LV) was employed to investigate ceramic microstructure. The bulk density and mechanical properties of the sample were measured using Archimedes’ method, respectively. The electrical properties of ceramics, such as dielectrics, ferroelectrics, and piezoelectrics, were investigated. Findings: XRD showed all samples had a single perovskite structure and no secondary phase. All sintered samples at different temperatures have a coexisting phase boundary between the rhombohedral phase and the tetragonal phase. The sintered ceramic at 1150°C with a soaking time of 4 h shows a maximum density of 5.89 g/cm3. In addition, the temperature at which the sintering process is carried out substantially impacts the electrical characteristics. Dielectric and electric field-induced strain (Smax) properties that sintered at 1150°C with a soaking time of 4 h exhibited the highest values of 4.489 and 0.39% (d33* of 650 pm/V), respectively. Research limitations/implications: The impact of the coercive field on the electrical breakdown characteristics of ceramics should be investigated further in the course of research that has to be carried out. Practical implications: The characterisation confirmed the effects of sintering temperature on the physical, phase, microstructure, and electrical properties of BNT-based ceramics. Originality/value: Such research demonstrates a suitable sintering temperature for producing BNT-BKT-SZ. The mechanical and electrical properties of a material are dependent on its sintering parameters. The ceramic system is suitable for piezoelectric and/or energy storage applications.

5

Evaluation of time history distribution characteristics of lightning electromagnetic field in heterogeneous soil

Xiang Yuanbing, Rao Pingping, Feng Weikang, Ouyang Peihao

Acta Geophysica

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2024

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Vol. 72, no. 2

793--805

EN

Existing underground lightning electromagnetic field predictive methods are only relevant to conductivity distributions that are homogeneous or layered. In order to expand the scope of application of lightning electromagnetic field computation, the effect of heterogeneous soil conductivity on the electromagnetic field of lightning return is examined in depth. The current distribution in the lightning return channel is characterized by the dual Heidler discharge channel base current and MTLE return model. Using the full-wave finite element approach, a two-dimensional axisymmetric model is created. The time distribution characteristics of the lightning electromagnetic field in a soil with heterogeneous conductivity are evaluated. According to the research, the lightning electromagnetic field's, horizontal electric field, vertical electric field, and azimuthal magnetic field components are negatively, bipolarly, and positively distributed in the subsurface, respectively. The horizontal electric field dominates the subterranean electromagnetic field. The high conductivity of the soil has a significant attenuation effect on the high-frequency components of the lightning electromagnetic field's three electromagnetic components. The initial response of the horizontal electric field of a nonhomogeneous soil is dependent on the conductivity at the surface of soil, followed by a gradual dependence on the conductivity in deeper soil sections. The subsurface distribution of vertical electric and azimuthal magnetic fields tend to stratify in response to a nonhomogeneous drop in soil conductivity.

6

Electrical properties for cold sprayed Nano copper oxide thin films

Muneer Roaa M., Idzikowski Adam, Al-Zubiedy Ali

Production Engineering Archives

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2023

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Vol. 29, Iss. 2

225-230

EN

This work is a Copper oxide (CuO) thin films were effectively produced using cold spray technique. The process take place in an inert gas (helium) without using catalyst. Nano CuO was deposited on a glass slide, using helium as carrier gas heated to 100, 200, 300, and 400oC, respectively on heated glass substrates at 300°C. The effect of structural and electrical properties was examined at each temperature for each film. AFM images show that the CuO thin film have different diameters ranging from 80 to 600 nm, and low surface roughness about 20.9 nm. The measured value of copper oxide resistivity was found to be decrease very much with the increasing temperature. All the result showed that copper oxide is suitable material for photovoltaic applications. This research is part of a larger work for the solar cells industry. Therefore, the aim of this research is to study the electrical properties of solar cells in the primary stages of manufacturing from available materials at low costs.

7

The application of piezoelectric materials to convert kinetic energy into electrical energy

Jureczko Mariola, Filas J., Mrówka Maciej

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 121, nr 2

231--237

EN

The main goal was to determine the efficiency of converting kinetic energy into electrical energy in piezoelectric materials. The article presents research results regarding the relationship between the number of piezoelectric transducers, the generated voltage, and the relationship between the pressure force and the induced voltage. Design/methodology/approach Experimental research began with determining whether the voltage generated by piezoelectric transducers connected in series is proportional to their number. The spacers were then applied to see if this increased the performance of the test platform. The latest tests were carried out at the author's measurement station. Findings The authors of the work researched electricity generation by piezoelectric materials, confirming their potential but showing limitations related to the brittleness of the materials. The work suggests the possibility of improving the efficiency of these materials by examining the influence of the pressure frequency on the obtained value of the generated voltage. Research limitations/implications The main limitation was the need to develop an optimal test platform design that would effectively use the piezoelectric potential of the transducers while preventing their damage. The results were not entirely satisfactory; therefore, future research is intended to optimise the parameters of transducers and the test platform to maximise efficiency in converting mechanical energy into electrical energy. Practical implications A practical application of the obtained results may be using energy produced using piezoelectric membranes in renewable energy, for example, to power streetlamps, road signs, or other low-power devices. Originality/value The main originality of the research is the possibility of its practical application. Research on such many piezoelectric membranes connected in series is rare, which makes this configuration original.

8

Tin oxide-titania based electronic system: synthesis, structural, microstructural and dielectric properties

Sahoo Limali, Bhuyan S., Das S.N.

Composites Theory and Practice

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2023

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R. 23, nr 4

183--190

EN

SnO2-TiO2, a composite ceramic electronic element was produced by employing a cost-effective and reliable method known as the solid-state synthesis process. The phase, microstructure, chemical composition, and electrical characteristics across a wide frequency range of 1 kHz-1 MHz were evaluated in detail to comprehend this electronic candidate as a capacitive component. The XRD study revealed a polycrystalline tetragonal structure with a crystallite size of 57.9 nm. The SEM micrograph revealed uniformly distributed grains and the calculated average grain size is 0.199 μm. A hydrophilic porous nature was also ascertained from the SEM micrograph. A high dielectric constant (2623) with low dielectric loss (7.5) resulted at the 1 kHz frequency and 400°C. The enhanced capacitive nature was determined by impedance spectroscopy under an extensive frequency and temperature range. The mechanism and nature of conduction at various temperatures were ascertained from the conductivity analysis. The electric modulus characteristics substantiate the non-Debye relaxation of this composite. Based on the comprehensive results, the synthesized component can have prospective applications as a capacitive component for humidity sensors and other electronic devices.

9

System wbudowany do badania właściwości elektrolizera

Świtalski Emilian, Górecki Krzysztof

Przegląd Elektrotechniczny

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2022

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R. 98, nr 1

151--154

PL

W pracy przedstawiono autorski system wbudowany do badania właściwości elektrolizera. Zaprezentowano koncepcję pracy rozważanego układu, schemat opracowanego układu, projekt płytki drukowanej wraz z opisem sposobu mocowania elementów elektronicznych. Pokazano też przebiegi czasowe napięć i prądów w wybranych częściach układu. Przedyskutowano uzyskane wyniki.

EN

The paper presents the author's embedded system for measurements of the properties of the electrolyser. The concept of operation of the considered system, a diagram of the this system, a design of a printed circuit board with a description of the method of the assembly of electronic components are presented. The waveforms of voltages and currents in selected parts of the system are also shown. The obtained results are discussed.

10

Impact of Carbon Nanotubes on the Mechanical and Electrical Properties of Silicone

Sałaciński Michał, Dydek Kamil, Leski Andrzej, Kozera Rafał, Mucha Mateusz, Karczmarz Wojciech

Fatigue of Aircraft Structures

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2022

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Iss. 14

135--153

EN

This paper presents the results of a structure study of a dispersion composite on a silicone matrix with a filler in the form of multi-walled carbon nanotubes (MWCNTs). The study aims to determine the effect of the filler on the composite mechanical properties and electrical conductivity. Materials that are electrically conductive and exhibit high mechanical properties can find applications in high-strain sensors. During the study, the characteristic properties of the susceptible materials, silicone alone and silicone with different filler contents (4%, 6%, and 8% by weight), were determined after curing. Microscopic observations were performed to assess the influence of carbon fillers on the material structure and to determine the level of homogeneity of the material. Examination of mechanical properties facilitated the determination of the Shor A hardness (ShA), stiffness, and Poisson’s ratio of the cured composites, depending on the nanotubes’ content. In parallel with the study of mechanical properties, the effect of loading, and the associated deformation of the samples, on the conductivity of the composite was investigated. Based on the results obtained, a discussion was carried out on the type of conductivity characteristic of silicone with different filler content as well as depending on the level of deformation of the samples.

11

Właściwości elektryczne i optyczne cienkich warstw WOx wytwarzanych metodą rozpylania magnetronowego i analiza ich współczynnika doskonałości

Dybała Julia, Mazur Michał

Biuletyn Wojskowej Akademii Technicznej

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2022

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Vol. 71, nr 2

15--25

PL

W artykule przeanalizowano właściwości optyczne i elektryczne cienkich warstw tlenku wolframu. Jest to materiał często stosowany między innymi w inteligentnych oknach, lustrach antyparowych i czujnikach gazów. zbadano pięć serii cienkich warstw tlenku wolframu, które zostały wytworzone w procesach rozpylania magnetronowego w atmosferze mieszaniny gazu roboczego (ar) oraz reaktywnego (O2) o różnej zawartości tlenu, tj. od 5% do 15%. Każdy z procesów przeprowadzany był przy tej samej wartości ciśnienia, odległości target - podłoże oraz w tym samym czasie. Grubość cienkich warstw zmierzona za pomocą profilometru optycznego wynosiła około 160 nm. zauważono, że wraz ze zwiększaniem się udziału gazu reaktywnego w procesie próbki zmieniały barwę od metalicznej, przez ciemnogranatową, po błękitną, jednocześnie stając się coraz bardziej przezroczyste. Pomiary właściwości elektrycznych wykonane za pomocą sondy czteroostrzowej, a także właściwości optycznych przeprowadzone z użyciem spektrofotometru wykazały, że zwiększanie udziału tlenu w procesie powodowało wzrost średniej transmisji światła w zakresie widzialnych długości fal oraz rezystywności cienkich warstw. W artykule przeanalizowano również współczynniki Figure of Merit określające jakość badanej próbki. Największą wartość współczynnika doskonałości otrzymano dla cienkiej warstwy tlenku wolframu, odznaczającej się stosunkowo dużą średnią transmisją światła w zakresie widzialnym przy niskiej wartości rezystywności. Przeprowadzone badania wykazały, że atmosfera gazowa podczas procesu rozpylania magnetronowego istotnie wpływa na właściwości optyczne i elektryczne cienkich warstw tlenku wolframu, co stwarza możliwość projektowania cienkowarstwowych powłok przeznaczonych do stosowania w transparentnej elektronice.

EN

In this article, optical and electrical properties of tungsten oxide thin films, prepared by magnetron sputtering in the atmosphere of various oxygen content, were analysed. Tungsten oxide is a material, which is widely used in modern applications such as smart windows, antisteam mirrors, and gas sensors. Five sets of tungsten oxide thin films were deposited by magnetron sputtering in the mixed argon-oxygen atmosphere composed of various content of reactive gas, i.e., from 5% to 15%. In each case, other deposition process parameters were the same. The thickness of the thin films was ca. 160 nm and it was measured with the optical profilometer. it was noticed that along with the increase in the proportion of reactive gas in the process, thin film samples changed their colour from metallic, through navy blue to blue and simultaneously they became increasingly transparent. Measurements of electrical properties, made using the four-point probe and optical properties, performed with the aid of a spectrophotometer showed that increasing the proportion of oxygen in the process increased the average transmission in the visible wavelength range and the resistivity of the prepared WOx thin films. in the article, the Figure of Merit (FoM) coefficients are also presented, which determine the quality of the thin film samples. it was shown that the highest value of the FoM was observed for WOx thin film characterised by a relatively high average transmission in the visible wavelength range and low value of resistivity. The performed measurements showed that the gas atmosphere during magnetron sputtering process leads to the tailoring of the optical and electrical properties of tungsten oxide thin films, which in turn makes it possible to design and apply such thin film coatings in transparent electronics.

12

Wpływ wygrzewania na właściwości cienkich warstw tlenku wanadu

Kiełczawa Szymon, Lubańska Aneta, Mazur Michał, Wiatrowski Artur

Elektronika : konstrukcje, technologie, zastosowania

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2021

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Vol. 62, nr 4

18--20

PL

W pracy przedstawiono wyniki badań wpływu wygrzewania na właściwości cienkich warstw tlenków wanadu (VxOy) wytworzonych metodą rozpylania magnetronowego. Cienkie warstwy bezpośrednio po naniesieniu oraz po wygrzewaniu w 200°C zostały poddane badaniom strukturalnym, optycznym oraz elektrycznym. Współczynnik transmisji cienkich warstw po wygrzewaniu zmniejszył się z około 70% na 50%. Z kolei rezystywność cienkiej warstwy tlenku wanadu po naniesieniu wynosiła 3.4·10⁴ Wcm, natomiast powłoki po wygrzaniu 1.6·10² Wcm. Badania współczynnika Seebecka wykazały, że wraz ze wzrostem różnicy temperatury między kontaktami elektrycznymi następuje zmiana typu przewodnictwa z dziurowego na elektronowy, a wygrzanie warstwy spowodowało uwydatnienie elektronowego typu przewodnictwa.

EN

This paper provides the research results of the influence of the post-process annealing of vanadium oxide (VxOy) thin films deposited by magnetron sputtering on their properties. As-deposited and annealed at 200°C thin films were analysed by means of their structural, optical and electrical properties. The transmission of thin films after annealing decreased from ca. 70% to 50%. In turn, the resistivity of the vanadium oxide thin films was equal to 3,4·10⁴ Wcm, while after post-process annealing it decreased to 1.6·10² Wcm. The studies of the Seebeck coefficient showed that with the increase of the temperature difference between the electrical contacts, the type of conductivity changes from hole to electron type, while the annealing of the layer enhances the electronic type of conductivity.

13

Właściwości elektryczne biowęgla pozyskiwanego metodą pirolizy z roślin energetycznych

Tomasik Marcin, Knaga Jarosław, Juliszewski Tadeusz, Lis Stanisław, Szul Tomasz

Przegląd Elektrotechniczny

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2020

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R. 96, nr 1

238--241

PL

Celem badań była analiza przewodności elektrycznej biowęgla uzyskanego z materiału organicznego metodą pyrolizy. W celu wykonania pomiarów właściwości elektrycznych biowęgla, zbudowano prototypowe urządzenie. Oprócz pomiarów właściwości elektrycznych umożliwia ono m.in. pomiar gęstości właściwej dowolnej próbki materiału sypkiego. W rozpatrywanym przypadku po napełnieniu komory roboczej i zagęszczeniu proszku otrzymywano pastylkę węglową. Dla niej określano pomiarami bezpośrednimi właściwości elektryczne tj.: spadek napięcia przy przepływie prądu przez próbkę (prąd stały i przemienny), oporność rezystora węglowego, wartość prądu przepływającego przez rezystor, indukcyjność oraz pojemność. Ponadto przy pomocy oscyloskopu rejestrowano charakterystyki dynamiczne napięcia w odniesieniu do prądu przemiennego przepływającego przez rezystor węglowy. Stwierdzono, że badanym próbkom można przypisać cechy obiektu elektronicznego o charakterze pojemnościowym.

XX

The aim of the research was to analyze the electrical conductivity of the obtained coal from organic material by pyrolysis. In order to take measurements of the electrical properties of the biochar, a prototype device was built. In addition to measurements of electrical properties, it enables measurement of the specific density of any sample of bulk material. In the case under consideration, after filling the working chamber and concentrating the powder, a carbon pellet was obtained. For it, direct electrical properties were determined by direct measurements, it is: voltage drop at the current flow through the sample (direct and alternating current), resistance of the carbon resistor, value of current flowing through the resistor, inductance and capacity. In addition, the dynamic characteristics of the voltage with respect to the alternating current flowing through the carbon resistor were recorded using the oscilloscope. It has been noted that capacitive features can be attributed to the test samples.

14

Granular metal-dielectric nanocomposites as an alternative to passive SMD

Boiko Oleksandr

Przegląd Elektrotechniczny

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2020

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R. 96, nr 12

158--161

EN

AC electrical properties of granular metal-dielectric nanocomposites (FeCoZr)x(PbZrTiO3)(100-x) have been examined. The study was carried for frequencies from 50 Hz to 1 MHz and measurement temperatures of 81 K – 293 K. The samples above percolation threshold xc considered to be resistive. Layers subdued to thermal treatment in air atmosphere behave as perfect capacitors, especially for low temperatures. Nanomaterials below xc demonstrate inductive-like properties. Tested samples could provide an alternative to conventional SMD components.

PL

Ziarniste nanokompozyty typu metal-dielektryk o strukturze (FeCoZr)x(PbZrTiO3)(100-x) zbadano pod kątem właściwości elektrycznych w przedziale temperatur pomiarowych 81 K – 293 K oraz częstotliwości pomiarowych 50 Hz – 1 MHz. Materiały powyżej progu perkolacji xc wykazują rezystancyjny charakter, warstwy wygrzane w temperaturze 573 K – typowo pojemnościowy typ, natomiast nanokompozyty poniżej xc poddane obróbce termicznej – właściwości indukcyjne. Badane nanostruktury stanowią alternatywę dla konwencjonalnych elementów SMD.

15

Subsolidus solution and ionic conductivity of rock-salt structured Li3+5xTa1−xO4 electroceramics

Shari S., Tan K. B., Khaw C. C., Zainal Z., Lee O. J., Chen S. K.

Materials Science Poland

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2020

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Vol. 38, No. 3

465--474

EN

Lithium tantalate solid solution, Li3+5xTa1−xO4 was prepared by conventional solid-state reaction at 925 °C for 48 h. The XRD analysis confirmed that these materials crystallized in a monoclinic symmetry, space group C2/C and Z = 8, which was similar to the reported International Crystal Database (ICDD), No. 98-006-7675. The host structure, β-Li3TaO4 had a rock-salt structure with a cationic order of Li+:Ta5+ = 3:1 over the octahedral sites. A rather narrow subsolidus solution range, i.e. Li3+5xTa1−xO4 (0 ⩽ x ⩽ 0.059) was determined and the formation mechanism was proposed as a replacement of Ta5+ by excessive Li+, i.e. Ta5+ ↔ 5Li+. Both Scherrer and Williamson-Hall (W-H) methods indicated the average crystallite sizes in the range of 31 nm to 51 nm. Two secondary phases, Li4TaO4.5 and LiTaO3 were observed at x = 0.070 and x = −0:013, respectively. These materials were moderate lithium ionic conductors with the highest conductivity of ~2.5 × 10-3 Ω -1∙cm-1 at x = 0, at 0 °C and 850 °C; the activation energies were found in the range of 0.63 eV to 0.68 eV.

16

Plasmonic nanostructures of SnO2:Sb thin film under gamma radiation response

Maged A. F., Amin M., Osman H., Nada L. A. M.

Materials Science Poland

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2020

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Vol. 38, No. 1

62--72

EN

This paper is a part of a natural dye solar cell project. Conductive transparent oxide (CTO) films have been deposited onto preheated glass substrates using a spray pyrolysis technique. The optical, electrical, structural properties as well as thermal annealing and gamma radiation response were studied. The average optical energy gap of doped films for direct allowed and direct forbidden transitions were found to be 3.92 and 3.68 eV, respectively. The plasmon frequency and plasmon energy after doping were found to be 3.48 x 1014 s-1 and 0.23 eV. The negative absorbance of the doped film was observed in UV-Vis range after applying both thermal annealing and ϒ-dose irradiation with 22 kGy. The negative refractive index of the doped film in UV range (220 – 300 nm) is promising for optical applications. The electron mobility μe reached a maximum of 27.4 cm2·V-1·s-1for Sb concentration of 10 %. The corresponding resistivity ρ and sheet resistance Rs reached their minimum values of 1.1 x 10-3 Ω·cm and 35 Ω·sq-1, respectively. The dopant concentration has been increased from 4.13 x 1019 to 2.1 x 1020cm-3. The doped film was found to exhibit three diffraction peaks associated with (2 2 2), (2 0 0), and (2 1 1) reflection planes, of which the peak of (2 2 2) of Sb2O3 and the peak of (2 0 0) were very close.

17

Comparison of electrical properties of CuO/n-Si contacts with Cu/n-Si

Özmenteş Reşit, Temirci Cabir

Materials Science Poland

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2020

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Vol. 38, No. 3

475--483

EN

In this study, CuO/n-Si/Al heterojunction contacts were fabricated by thermal evaporation technique. Electrical characteristics of the samples were investigated with the current-voltage (I-V), capacitance-voltage/frequency (C-V/f), and conductance-voltage (G/V) measurements at room temperature. Also, Cu/n-Si/Al Schottky contact was produced as a reference sample to investigate the electrical properties of the samples. The values of ideality factor (n), barrier height (φb) and series resistance (Rs) of the samples were calculated from the forward bias current-voltage (I-V) and reverse bias capacitance-voltage (C-V) characteristics. Also, for checking the consistency of the results, Cheung and Norde functions were used. The experimental result values of CuO/n-Si contact were compared with the values of the reference Cu/n-Si Schottky diode. It was observed that the values of the ideality factor and barrier height of the CuO/n-Si heterojunction were higher than those of the Cu/n-Si Schottky contact, while the series resistance was lower. Also, it has been observed that the value of capacitance decreased with increasing frequency and after a certain value of frequency it was almost constant. The ideality factor of CuO/n-Si/Al heterostructure is about 2.40 and so, it is not close to the ideal behavior.

18

Influence of Particle Size and Sintering Temperatures on Electrical Properties of 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 Lead Free Ceramics

Gul Mert, Gurbuz Mevlüt, Gokceyrek Abdi B., Toktaş Aysegül, Kavas Taner, Dogan Aydın

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

609--614

EN

In this study, lead-free 0.94 Na0.5 Bi0.5 TiO3 -0.06BaTiO3 (NBT-BT) compositions at morphotropic phase boundary were successfully synthesized by solid-state reaction method. The effects of the particle size for various milling time (12-24-48 hours) and sintering temperatures (1100-1125-1150-1175°C for 2 h) on the electrical properties of the NBT-BT ceramics were evaluated. Experimental results showed that particle size and sintering temperatures significantly affect the electrical properties of NBT-BT ceramics. The particle size of the ceramic powders decreasing while milling time increases to 48 hours. Particle size values for 0, 12, 24 and 48 hours (h) milled powders were measured as nearly 1.5 μm, 1 μm, 700 nm, and 500 nm respectively. The bulk density enhanced with increasing sintering temperature and showed the highest value (5.73 g/cm3) at 1150°C for 48 h milled powder. Similarly, the maximum piezoelectric constant (d33 ) = 105 pC/N, electromechanical coupling coefficient (kp ) = 25.5% and dielectric constant (KT) = 575 were measured at 1150°C for 48 h milled powder. However, mechanical quality factor (Qm ) was reduced from 350 to 175 with decreasing particle size. Similarly, remnant polarization was dropped by decreasing powder particle size from 56 μC/cm2 to 45 μC/cm2.

19

Measurements of physicochemical and electrical properties of insulating liquids

Zdanowski Maciej

Poznan University of Technology Academic Journals. Electrical Engineering

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2019

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No. 98

181--193

EN

This paper provides a comparative analysis of key physicochemical and electrostatic parameters of Trafo En oil and Midel 7131® synthetic ester, changing in temperature and accelerated thermal ageing. The parameters tested included the density, kinematic viscosity, conductivity and relative electric permittivity. In addition to that, Electrostatic Charging Tendency (ECT) tests of those fluids were performed in a flow system using cellulose and aramid paper pipes. The effect of liquid flow velocity combined with temperature variations and accelerated ageing time on the streaming electrification current generated was determined. The relationship between the fluid electrification degree and measuring pipe material was also investigated.

20

Optimization and characterization of NiO thin films prepared via NSP technique and its P-N junction diode application

Saju Joseph, Balasundaram O. N.

Materials Science Poland

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2019

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Vol. 37, No. 3

338--346

EN

The present work reports on the optimization of substrate temperature, molar concentration and volume of the solution of nickel oxide (NiO) thin films prepared by nebulizer spray pyrolysis (NSP) technique. NiO films were optimized and characterized by XRD, SEM, EDX, UV-Vis and I-V measurements. Based on XRD analysis, the molar concentration, volume of solution and substrate temperature of the prepared NiO films were optimized as 0.20 M, 5 mL and 450 °C for P-N diode applications. The XRD pattern of the optimized NiO film revealed cubic structure. The surface morphological variations and elemental composition were confirmed by SEM and EDX analysis. The optical properties were studied with UV-Vis spectrophotometer and the minimum band gap value was 3.67 eV for 450 °C substrate temperature. Using J-V characteristics, the diode parameters: ideality factor n and barrier height Фb values of p-NiO/N-Si diode prepared at optimum conditions, i.e. 450 °C, 0.2 M, 5 mL, were evaluated in dark and under illumination.