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Number of results: 63
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Abstract

Studies of noise properties of thick-film conducting lines from Au or PdAg conductive pastes on LTCC or alumina substrates are reported. Experiments have been carried out at the room temperature on samples prepared in the form of meanders by traditional screen-printing or laser-shaping technique. Due to a low resistance of the devices under test (DUTs), low-frequency noise spectra have been measured for the dc-biased samples arranged in a bridge configuration, transformer-coupled to a low-noise amplifier. The detailed analysis of noise sources in the signal path and its transfer function, including the transformer, has been carried out, and a procedure for measurement setup self-calibration has been described. The 1/f noise component originating from resistance fluctuations has been found to be dominant in all DUTs. The analysis of experimental data leads to the conclusion that noise is produced in the bends of meanders rather than in their straight segments. It occurs that noise of Au-based laser-shaped lines is significantly smaller than screen-printed ones. PdAg lines have been found more resistive but simultaneously less noisy than Au-based lines.
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Authors and Affiliations

Adam Witold Stadler
Andrzej Kolek
Krzysztof Mleczko
Zbigniew Zawiślak
Andrzej Dziedzic
Damian Nowak
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Abstract

The paper presents general information on LTCC materials, manufacturing processes and properties of fired modules. A Multichip Module package has been the main application of Low Temperature Cofired Ceramic (LTCC) technology. Recently, this technology is also used for production of sensors, actuators and microsystems. The research and development on the LTCC sensors and microsystems carried out in the Laboratory of Thick Film Microsystems at Wroclaw University of Technology are presented. LTCC microfluidic system is described in detail. Moreover, a short information is given on other LTCC applications .

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Authors and Affiliations

L.J. Golonka
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Abstract

Recently a new technology of piezoelectric transducers based on PZT thick film has been developed as a response to a call for devices working at higher frequencies suitable for production in large numbers at low cost. Eight PZT thick film based focused transducers with resonant frequency close to 40 MHz were fabricated and experimentally investigated. The PZT thick films were deposited on acoustically engineered ceramic substrates by pad printing. Considering high frequency and non-linear propagation it has been decided to evaluate the axial pressure field emitted (and reflected by thick metal plate) by each of concave transducer differing in radius of curvature - 11 mm, 12 mm, 15 mm, 16 mm.

All transducers were activated using AVTEC AVG-3A-PS transmitter and Ritec diplexer connected directly to Agilent 54641D oscilloscope. As anticipated, in all cases the focal distance was up to 10% closer to the transducer face than the one related to the curvature radius. Axial pressure distributions were also compared to the calculated ones (with the experimentally determined boundary conditions) using the angular spectrum method including nonlinear propagation in water. The computed results are in a very good agreement with the experimental ones. The transducers were excited with Golay coded sequences at 35-40 MHz. Introducing the coded excitation allowed replacing the short-burst transmission at 20 MHz with the same peak amplitude pressure, but with almost double center frequency, resulting in considerably better axial resolution. The thick films exhibited at least 30% bandwidth broadening comparing to the standard PZ 27 transducer, resulting in an increase in matching filtering output by a factor of 1.4-1.5 and finally resulting in a SNR gain of the same order.

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Authors and Affiliations

Marcin Lewandowski
Andrzej Nowicki
Janusz Wójcik
Ryszard Tymkiewicz
Rasmus Lou-Moller
Wanda Wolny
Tomasz Zawada
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Abstract

Graphene is a very promising material for potential applications in many fields. Since manufacturing technologies of graphene are still at the developing stage, low-frequency noise measurements as a tool for evaluating their quality is proposed. In this work, noise properties of polymer thick-film resistors with graphene nano-platelets as a functional phase are reported. The measurements were carried out in room temperature. 1/f noise caused by resistance fluctuations has been found to be the main component in the specimens. The parameter values describing noise intensity of the polymer thick-film specimens have been calculated and compared with the values obtained for other thick-film resistors and layers used in microelectronics. The studied polymer thick-film specimens exhibit rather poor noise properties, especially for the layers with a low content of the functional phase.

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Authors and Affiliations

Krzysztof Mleczko
Piotr Ptak
Zbigniew Zawiślak
Marcin Słoma
Małgorzata Jakubowska
Andrzej Kolek
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Abstract

LTCC-based pressure sensors are promising candidates for wet-wet applications in which the effect of the surrounding media on the sensor's characteristics is of key importance. The effect of humidity on the sensor's stability can be a problem, particularly in the case of capacitive sensors. A differential mode of operation can be a good solution, but manufacturing the appropriate sensing capacitors remains a major challenge. In the case of piezoresistive sensors the influence of humidity is less critical, but it still should be considered as an important parameter when designing sensors for low-pressure ranges. In this paper we discuss the stability of the sensors' offset characteristics, which was inspected closely using experimental and numerical analyses.

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Authors and Affiliations

Darko Belavič
Marina Zarnik
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Abstract

Measurement of low-frequency noise properties of modern electronic components is a very demanding challenge due to the low magnitude of a noise signal and the limit of a dissipated power. In such a case, an ac technique with a lock-in amplifier or the use of a low-noise transformer as the first stage in the signal path are common approaches. A software dual-phase virtual lock-in (VLI) technique has been developed and tested in low-frequency noise studies of electronic components. VLI means that phase-sensitive detection is processed by a software layer rather than by an expensive hardware lock-in amplifier. The VLI method has been tested in exploration of noise in polymer thick-film resistors. Analysis of the obtained noise spectra of voltage fluctuations confirmed that the 1/f noise caused by resistance fluctuations is the dominant one. The calculated value of the parameter describing the noise intensity of a resistive material, C = 1·10−21 m3, is consistent with that obtained with the use of a dc method. On the other hand, it has been observed that the spectra of (excitation independent) resistance noise contain a 1/f component whose intensity depends on the excitation frequency. The phenomenon has been explained by means of noise suppression by impedances of the measurement circuit, giving an excellent agreement with the experimental data.
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Authors and Affiliations

Adam Witold Stadler
Andrzej Kolek
Zbigniew Zawiślak
Andrzej Dziedzic
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Abstract

Studies of electrical properties, including noise properties, of thick-film resistors prepared from various resistive and conductive materials on LTCC substrates have been described. Experiments have been carried out in the temperature range from 300 K up to 650 K using two methods, i.e. measuring (i) spectra of voltage fluctuations observed on the studied samples and (ii) the current noise index by a standard meter, both at constant temperature and during a temperature sweep with a slow rate. The 1/f noise component caused by resistance fluctuations occurred to be dominant in the entire range of temperature. The dependence of the noise intensity on temperature revealed that a temperature change from 300 K to 650 K causes a rise in magnitude of the noise intensity approximately one order of magnitude. Using the experimental data, the parameters describing noise properties of the used materials have been calculated and compared to the properties of other previously studied thick-film materials.

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Authors and Affiliations

Adam Witold Stadler
Zbigniew Zawiślak
Andrzej Dziedzic
Damian Nowak
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Abstract

Semiconductive - resistive sensors of toxic and explosive gases were fabricated from nanograins of SnO2 using thick-.lm technology. Sensitivity, selectivityand stabilityof sensors working in di.erent temperature depend on the way the tin dioxide and additives were prepared. A construction also plays an important role. The paper presents an attitude towards the evaluation of transport of electrical charges in semiconductive grain layer of SnO2, when dangerous gases appear in the surrounding atmosphere.

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Authors and Affiliations

B. Licznerski
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Abstract

This paper presents the concept and modern technological approach to the fabrication of discrete, integrated and integral micropassives. The role of these components in modern electronic circuits is discussed too. The material, technological and constructional solutions and their relation with electrical and stability properties are analyzed in details for linear and nonlinear microresistors made and characterized at the Faculty of Microsystem Technology, Wrocław University of Technology.

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Authors and Affiliations

A. Dziedzic
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Abstract

The film art of the Russian Empire, in the light of the current state of research, may not be completely terra incognita, and yet a number of issues on this topic still need to be elaborated and saved from oblivion. The subject of the present research are the lost or only partially preserved horror movies filmed in the country of the last tsar of Russia – Nicholas II. The author recalls the circumstances of the creation of specific films, as well as the critical reception of such productions as Vasily Goncharov’s Viy (1909), At Midnight in the Graveyard (1909/1910) by the same director, The Vampire Woman (1915) by Viatcheslav (Victor) Tourjansky or two films by Ladislas Starevich: The Portrait (1915) and another screen adaptation of Viy (1916?).
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Authors and Affiliations

Marcin Cybulski
1
ORCID: ORCID

  1. Lublin, Katolicki Uniwersytet Lubelski Jana Pawła II
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Abstract

Numerous films, especially reinterpretations of the Gospel, can be read as loci theologici. Nevertheless, it’s important to recognize that the commercially motivated interest of filmmakers has its theological consequences: a resulting challenge is the catechetical use of apocryphal films in the pastoral praxis of the Church. The paper recalls main documents of the Church, relating to the cinema, stressing the absence of official teaching on the cinema in the last 20 years. Films, produced with commercial motivation, are often kitsch; it’s a result of tendencies to gain the possibly large audiences and to fulfill their expectations. An analysis of selected films (e.g. The Passion of the Christ and Son of God) indicates that the kitschy audiovisual apocrypha, superficial, emotional and lacking of authenticity, become a false filmic transformation of the message of the Bible. The paper postulates the need of constructing a theology of film: its object could be audiovisual texts, which extra-ecclesial theologies influence religious imagination and thinking of the viewers.

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Authors and Affiliations

Ks. Marek Lis
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Abstract

The purpose of this article is to show the contribution of fi lm in shaping of social imagination of Katyń crime in Poles’ minds. Author places described fi lms in the background of today’s knowledge.
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Authors and Affiliations

Tadeusz Lubelski
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Abstract

This paper employs the Cognitive Linguistics paradigm to argue that flirtation, especially verbal, may be interpreted as a phenomenon resulting from the working of two conceptual mechanisms, namely metaphor and metonymy. As far as the corpus of the present paper is concerned, the analysis is predominantly based on dialogues extracted from the film “Double Indemnity” (1944) directed by Billy Wilder.
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Authors and Affiliations

Agnieszka Grząśko
1

  1. University of Rzeszow
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Abstract

Time-lapse imagery allows us to witness, first-hand, how plants grow and heal, sway in cyclical motions, and even “dance” in reaction to various environmental factors.
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Authors and Affiliations

Urszula Zajączkowska
1

  1. Department of Forest Botany, Warsaw University of Life Sciences (SGGW)
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Abstract

The aim of this work was to produce a thin SnO2 film by a technique combining the sol-gel method and electrospinning from a solution based on polyvinylpyrrolidone and a tin chloride pentahydrate as a precursor. The spinning solution was subjected to an electrospinning process, and then the obtained nanofiber mats were calcined for 10 h at 500°C. Then, the scanning electron microscopy morphology analysis and chemical composition analysis by X-ray microanalysis of the manufactured thin film was performed. It was shown that an amorphous-crystalline layer formed by the SnO2 nanofiber network was obtained. Based on the UV-Vis spectrum, the width of the energy gap of the obtained layer was determined.

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Authors and Affiliations

W. Matysiak
T. Tański
W. Smok
S. Polishchuk
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Abstract

Thin films of crystallized LaCoO3 were grown on Si substrate by Pulsed Laser Deposition at different temperatures (750°C, 850°C and 1000°C). The structural characterization of the LaCoO3 thin films was done by combining several techniques: Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM), Transmission Electron Microscopy (TEM) and Grazing Incidence X-Ray Diffraction (GIXRD). The thin films crystallized in the expected rhombohedral phase whatever the deposition temperature, with an increase of crystallite size from 70 nm at 750°C to 100 nm at 1000°C, and an average thickness of the thin films of less than 200 nm. At 850°C and 1000°C, the thin films are crack-free, and with a lower number of droplets than the film deposited at 750°C. The grains of LaCoO3 film deposited at 850°C are columnar, with a triangular termination. At 1000°C, an intermediate layer of La2Si2O7 was observed, indicating diffusion of Si into the deposited film.

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Authors and Affiliations

M. Jędrusik
Ł. Cieniek
A. Kopia
ORCID: ORCID
Ch. Turquat
Ch. Leroux
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Abstract

The article is a review of the book by Natalie Zemon Davis Slaves on Screen. Film and Historical Vzsion, Cambridge Mass. 2000.
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Authors and Affiliations

Piotr Witek
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Abstract

Indium gallium zinc oxide (In–Ga–Zn–O) thin films, which are transparent conductive films for liquid crystals and electroluminescent displays, were fabricated via singlestep sputter deposition using one target containing different proportions of indium oxide, gallium oxide, and zinc oxide powders. Experimental results suggest that the In–Ga–Zn–O thin films can be prepared using the method of single-step radio frequency (RF) sputter deposition, applying a powder target containing indium oxide, gallium oxide, and zinc oxide. The In–Ga–Zn–O thin films were prepared on Si substrates, and the deposition rate depended on the target composition. In these plasma processes, electron density and temperature were essentially independent of target composition. The prepared films were very smooth with a root-mean-square roughness of less than 10 nm. The crystallinity of the ZnO peak was observed in all the films; whereas the In and Ga peaks were not observed in the films prepared. The X-ray photoelectron spectroscopy of the films also revealed that the elemental concentration ratio of In–Ga–Zn–O thin films could be prepared using one target, and that can be easily controlled by ratios in the In 2O 3/Ga 2O 3/ZnO composition in the powder target. The transmittances were > 75% at 800 nm for all the target mixtures, and increased with increasing In 2O 3 in the powder target.
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Authors and Affiliations

Takahiko Satake
1
ORCID: ORCID
Hiroharu Kawasaki
2
Shin-Ichi Aoqiu
1

  1. Graduate School of Engineering Sojo University, Ikeda Nishi-ku Kumamoto City, Japan
  2. Department of Electrical and Electronic Engineering, National Institute of Technology, Sasebo College, Okishin-machi, Sasebo City, Nagasaki Pref., Japan
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Abstract

This paper discusses the idea of combining a photovoltaic system with a heating film system to heat residential buildings. The analysis was performed for a newly built single-family house in Warsaw or its vicinity. The authors have selected the size of the photovoltaic installation, calculated the costs incurred by the user for the installation of a hybrid system, which were additionally compared to the cost of installing a gas installation (gas boiler) used for heating the building. The calculations were made for a single-family house with a usable area of 120 m2, the demand for utility energy for heating purposes in the newly built house was in the range of 10–50 kWh/m2/year. Based on the adopted parameters, the authors evaluated the economic efficiency of both investments (solutions) determining their net present values (NPV). The analysis takes the energy needed only for heating purposes into account.
NPV for a heating system with a gas boiler with an investment outlay EUR 8,000 for buildings purchased for utility energy in the amount of 20 kWh/m2/year and the price for natural gas EUR 0.04 /kWh will be EUR –10,500 (for 15 years, discount rate r = 3%). For the same thermal needs (energy required) of the building, NPV for heating films + photovoltaic (HF + PV) will amount to – EUR 8,100. Comparing the variants will get a EUR 2,400 higher NPV for HF + PV. With a utility energy demand for heating purpose of 50 kWh/m2/year and gas heating installation investment cost of EUR 7,000, the NPV for both variants will be equal for natural gas price = EUR 0.035/kWh.
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Bibliography

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Authors and Affiliations

Krystian Majchrzak
1 2
Monika Pepłowska
3
ORCID: ORCID
Piotr Olczak
1
ORCID: ORCID

  1. Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Kraków, Poland
  2. Instaway Institute, Warszawa, Poland
  3. Mineral and Energy Economy Research Institute, Polish Academy of Sciences, Kraków, Poland
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Abstract

Systematic attempts to maximise the efficiency of gas turbine units are achieved, among other possibilities, by increasing the temperature at the inlet to the expansion section. This requires additional technological solutions in advanced systems for cooling the blade rows with air extracted from the compressor section. This paper introduces a new mathematical model describing the expansion process of the working medium in the turbine stage with air film cooling. The model includes temperature and pressure losses caused by the mixing of cooling air in the path of hot exhaust gases. The improvement of the accuracy of the expansion process mathematical description, compared with the currently used models, is achieved by introducing an additional empirical coefficient estimating the distribution of the cooling air along the profile of the turbine blade. The new approach to determine the theoretical power of a cooled turbine stage is also presented. The model is based on the application of three conservation laws: mass, energy and momentum. The advantage of the proposed approach is the inclusion of variable thermodynamic parameters of the cooling medium. The results were compared with the simplified models used in the literature: separate Hartsel expansion, mainstream pressure, weighted-average pressure and fully reversible. The proposed model for expansion and the determination of theoretical power allows for accurate modelling of the performance of a cooled turbine stage under varying conditions.
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Authors and Affiliations

Paweł Trawiński
1

  1. Institute of Heat Engineering, Warsaw University of Technology, Nowowiejska 21/25, 00-665, Warsaw, Poland
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Abstract

The paper presents the idea to improve the performance of thin film photovoltaic cells by a light capture enhancement through the introduction of down shifting energy converters. Luminescent down shifting layers convert high-energy photons (UV light) into low-energy ones (visible light), which are more efficient in a photovoltaic conversion. For this purpose, the application of a thin layer composed of zinc oxide (ZnO) nanoparticles deposited onto a thin film solar cell is proposed. The paper presents both experimental and theoretical results of this approach. Conducted investigations include an analysis of ZnO nanoparticle layers, deposited in two independent technology methods. The results showed that ZnO nanoparticles have a great potential of application as down converting layers and can be implemented to improve the efficiency of photovoltaic cells, especially in the field of thin film PV structures. The proposed new deposition method can potentially be used in some industrial photovoltaic applications.

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Authors and Affiliations

K. Znajdek
Maciej Sibiński
ORCID: ORCID
Z. Lisik
A. Apostoluk
Y. Zhu
B. Masenelli
P. Sędzicki
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Abstract

In this paper an analysis of the surface properties of (Ti,Pd,Eu)Ox thin films prepared by magnetron sputtering has been described. In particular, the results of composition and structure investigations were studied in relation to the surface state and optical properties. It was found that (Ti,Pd,Eu)Ox film was nanocrystalline and had a rutile structure. The average crystallites size was equal to 7.8 nm. Films were homogeneous and had densely packed grains. Investigation of the surface properties by XPS showed that titanium was present at 4+ state (in the TiO2form), palladium occurred as PdO2(also at 4+ state), while europium was in Eu2O3form (at 3+ state). In comparison with the unmodiffied TiO2, the coating with Pd and Eu additives had a rather high transparency (approx. 47%) in the visible light range, its optical absorption edge was shifted towards into the longer wavelengths (from 345 nm to 452 nm), and the width of optical energy gap Egopt was nearly twice lower (1.82 eV). Besides, the resistivity of (Ti,Pd,Eu)Ox at room temperature was 1×103 Wcm. In the case of the film as-deposited on Si substrate (p-type) the generation of photocurrent as a response to light beam excitation (λexc = 527 nm) was observed.

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Authors and Affiliations

D. Wojcieszak
D. Kaczmarek
J. Domaradzki
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Abstract

ZnO thin layers were deposited on p-type silicon substrates by the sol-gel spin-coating method and, then, annealed at various temperatures in the range of 573–873 K. Photoluminescence was carried out in the temperature range of 20–300 K. All samples showed two dominant peaks that have UV emissions from 300 nm to 400 nm and visible emissions from 400 nm to 800 nm. Influence of temperature on morphology and chemical composition of fabricated thin layers was examined by XRD, SEM, FTIR, and Raman spectroscopy. These measurements indicate that ZnO structure is obtained for samples annealed at temperatures above 573 K. It means that below this temperature, the obtained thin films are not pure zinc oxide. Thus, annealing temperature significantly affected crystallinity of the thin films.

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Authors and Affiliations

M. Sypniewska
R. Szczesny
P. Popielarski
ORCID: ORCID
K. Strzalkowski
B. Derkowska-Zielinska

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