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2
Content available remote Wymagania dla betonu wodoszczelnego
PL
W artykule przedstawiono opis wymagań stawianych betonowi wodoszczelnemu. Omówiono charakterystykę betonu wodoszczelnego oraz wymagania dotyczące wodoszczelności w polskich normach dotyczących tego zagadnienia. Skupiono się na wymaganiach dotyczących wodoszczelności betonu oraz na wymaganiach dotyczących wodoszczelności całej konstrukcji. Osobne miejsce poświęcono zagadnieniom projektowania w technologii betonu wodoszczelnego. Omówiono jego specyfikę oraz sposoby pielęgnacji. Przybliżono także zasady realizacyjne technologii betonu wodoszczelnego.
EN
The paper presents a description of requirements concerning waterproof concrete. Discussed were properties of water-tight concrete and relevant tightness requirements set forth in Polish standards with respect to this issue. The work focuses on requirements concerning water-tightness and those applicable to the water-tightness of the entire structure. A separate section focuses on design issues with respect to water-tight concrete technologies. Its properties and methods of care have been described. the rules of practical usage of water-tight concrete technologies are also described.
PL
W pracy przedstawiono wyniki badań żelaznych spieków zawierających różne ilości heksagonalnego azotku boru h-BN. Badania tribologiczne przeprowadzono za pomocą maszyn KEWAT-6 i KEWAT-1 w Zakładzie Tribologii, Inżynierii Powierzchni i Logistyki Płynów Eksploatacyjnych IPMiT WME WAT. Stwierdzono, że zawartość do 3% wagowo azotku boru w żelaznym spieku proszku żelaza Höganas NC.100.24 poprawia skutecznie właściwości tribologiczne spieku, tj. zmniejsza wartość współczynnika tarcia, nie zwiększając zużycia spiekanych próbek mimo nieznacznego spadku ich twardości. Wyniki tych badań były podstawą do wykonania pełnogabarytowych tulei porowatych zawierających azotek boru h-BN w spieku, które następnie poddano badaniom stanowiskowym w ramach projektu badawczego rozwojowego PBR/15-249/2007/WAT-OR00002904 [L. 1], finansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego w latach 2007–2011.
EN
The results of research on the iron sinters containing various amounts hexagonal boron nitride h-BN are presented in this paper. The tribological research was realised with KEWAT-6 and KEWAT-1 machines at the Department of Tribology, Surface Engineering and Service Fluids Logistics of the Institute of Motor Vehicles and Transportation, FME, MUT. The paper concludes that boron nitride up to 3% by weight in the iron sinter of Höganas NC.100.24 iron powder efficiently increases tribological properties of the sinter, i.e. it lowers the value of the friction factor without increasing the wear of sintered samples. However, their hardness was slightly decreased. These results were the basis for making some full-size porous sleeves, which included boron nitride h-BN in the sinter. The sleeves were then subjected to stand tests within the framework of the development and research project number PBR/15-249/2007/WAT-OR00002904 [L. 1], financed by the Ministry of Science and Higher Education, 2007–2011. Very advantageous results were obtained from these tests, which allowed us to make a patent claim [L. 8].
EN
The fragmentation of coal plays a significant role during combustion process in circulating fluidized-bed boilers because it accelerates combustion and influences the distribution of particle sizes in the bed. Fine char particles produced by comminution can be carried out and increase the heat loss due to incomplete carbon conversion. The main objective of this study was to determine the degree of primary and secondary fragmentation for coal particles during oxy-combustion in a circulating fluidized bed. The effects of coal type, particle size, bed temperature and oxygen concentration on the extend of primary and secondary fragmentation have been determined. Fragmentation tests were conducted in a 12-kW bench-scale oxy-CFB combustor. The experiments with one brown and two hard Polish coals were carried out in air (base case) and mixtures of O2/CO2 with oxygen concentrations in the range from 21% to 40%vol.
PL
W pracy przeanalizowano oddziaływanie stężenia tlenu w mieszaninie O2/CO2 na przebieg procesu spalania paliw zawiesinowych, utworzonych z różnych typów węgli. Dla porównania pomiary przeprowadzono również w strumieniu powietrza. Spalanie tlenowe jest postrzegane współcześnie jako jeden z głównych kierunków rozwoju zero emisyjnych technologii energetycznych. Również badania spalania zawiesinowych paliw węglowo-wodnych nabierają coraz większego znaczenia, szczególnie w naszym kraju ze względu na niekorzystny bilans paliwowy, zdominowany przez węgiel kamienny i brunatny. W ramach pracy wykonano pomiary przebiegu zmian temperatury na powierzchni i w środku paliwa zawiesinowego, ubytku jego masy, czasu i temperatury zapłonu paliwa za pośrednictwem części lotnych wydzielających się z zawiesiny oraz wyznaczono całkowity czas procesu. Od Redakcji: Artykuł został wydrukowany ponownie, ponieważ w poprzednim zeszycie (Vol.11 (2011) nr 1-2) podczas opracowania redakcyjnego wstawiono do tekstu niewłaściwe rysunki. Redakcja przeprasza autorów za pomyłkę.
EN
Combustion process of coal-water slurries in O2/CO2 mixtures is analyzed in this paper. The combustion in oxygen is one from the zero - emission energetic technologies, From second side, the necessity to undertake the research of coal-water combustion in our country results from the fuel structure of the Polish power industry where 97% of electric energy is produced from coal. The effect of oxygen concentration on combustion process of coal-water slurries, made from different types of coals, is determined, Detailed comparisons of fuels temperatures, mass loss, ignition time, devolatilization time and char combustion time have been made for coal-water slurries combusted in air and various O2/CO2 mixtures.
8
Content available remote Uncooled MWIR and LWIR photodetectors in Poland
EN
The history, status, and recent progress in the middle and long wavelength Hg1-xCdxTe infrared detectors operating at near room temperatures are reviewed. Thermal generation of charge carriers in narrow gap semiconductor is a major limitation or sensitivity. Cooling is a straightforward way to suppress thermal generation of charge carriers and reduce related noise. However, at the same time, cooling requirements make infrared systems bulky, heavy, and inconvenient in use. A number of concepts to improve performance of photodetectors operating at near room temperatures have been proposed and implemented. Recent considerations of the fundamental detector mechanisms suggest that near perfect detection can be achieved without the need for cryogenic cooling. This paper, to a large degree, is based on the research, development, and commercialization of uncooled HgCdTe detectors in Poland. The devices have been based on 3D-variable band gap and doping level structures that integrate optical, detection and electric functions in a monolithic chip. The device architecture is optimized for the best compromise between requirements of high quantum efficiency, efficient and fast collection of photogenerated charge carriers, minimized thermal generation, reduced parasitic impedances, wide linear range, wide acceptance angles and other device features. Recent refinements in the devices design and technology have lead to sensitivities close to the background radiation noise limit, extension of useful spectral range to > 16 µm wavelength and picosecond range response times. The devices have found numerous applications in various optoelectronic systems. Among them there are fast scan FTIR spectrometers developed under MEMFIS project.
9
Content available remote Insight into precursor kinetics using an infrared gas analyser
EN
Precursor kinetics and its influence on MOCVD growth was investigated using an infrared absorption gas analyser. After several refinements, the analyser was able to be used to measure time dependent concentrations of precursors in the growth zone. Changes were induced by periodic switching of corresponding bubbler valves. It was proved that precursor transport could be accurately described by the combined plug flow and perfectly mixed tank model. The studies of the precursor trans-port are strategically important for the growth of multilayer structures, when growth time of particular layers becomes comparable to delays and time constants. One example is quantum wells or interdiffused multilayer process (IMP) used in the growth of Hg1-xCdxTe heterostructures, where knowledge of precursor transport characteristics is vital for understanding and properly designing that growth. The model parameters, sc. the delays and time constants for DIPTe and DMCd, were evaluated for various growth conditions and then successfully used to optimise the growth of complex Hg1-xCdxTe heterostructures.
10
Content available remote Control of acceptor doping in MOCVD HgCdTe epilayers
EN
The acceptor doping of mercury cadmium telluride (HgCdTe) layers grown by MOCVD are investigated. (111)HgCdTe layers were grown on (100)GaAs substrates at 350°C using horizontal reactor and interdiffused multilayer process (IMP). TDMAAs and AsH3 were alternatively used as effective p-type doping precursors. Incorporation and activation rates of arsenic have been studied. Over a wide range of Hg₁₋xCdxTe compositions (0.17 < x < 0.4), arsenic doping concentration in the range from 5×10¹⁵ cm⁻³ to 5×10¹⁷ cm⁻³ was obtained without postgrowth annealing. The electrical and chemical properties of epitaxial layers are specified by measurements of SIMS profiles, Hall effect and minority carrier lifetimes. It is confirmed that the Auger-7 mechanism has decisive influence on carrier lifetime in p-type HgCdTe epilayers.
PL
W pracy przestawiono wyniki badań eksperymentalnych procesu fragmentacji czterech różnych typów węgli podczas spalania w temperaturze 850°C w mieszaninach O2/CO2 oraz dla porównania w powietrzu. Wyznaczono mechanizmy fragmentacji dla trzech węgli kamiennych (typu 31.1, 32.1 i 32.2) i węgla brunatnego, jak również określono oddziaływanie podwyższonych koncentracji tlenu na proces fragmentacji. Wyznaczono prawdopodobieństwo i stopień fragmentacji w wyniku szoku termicznego, fragmentacji pierwotnej oraz wtórnej dla badanych węgli. Przeanalizowano także wpływ typu węgla, średnicy ziaren oraz temperatury w komorze spalania na proces fragmentacji.
EN
Results of experimental investigation of the fragmentation process for four different types of coals during combustion in air and O2/CO2 mixtures are presented in this paper. The mechanisms of fragmentation for three hard coals and one brown coal are determined. Probability and degree of fragmentation due to thermal shock, primary fragmentation and secondary fragmentation are also determined. The effects of coal rank, temperature in combustion chamber and particle size on fragmentation have been also determined.
PL
Artykuł przedstawia najciekawsze wyniki prac badawczych uzyskanych w Vigo System S.A. w ramach realizacji zadania nr 5 PBZ -MNiSW 02/I/2007 pt.: "Niechłodzone detektory podczerwieni z HgCdTe". W pracy przedstawiony został postęp w technologii heterostruktur z HgCdTe i własności uzyskanych z nich detektorów średniej i dalekiej podczerwieni (MWIR i LWIR).
EN
This article presents scientific results of works carried out in Vigo System S.A., accomplished during realization of grant 5 PBZ-MNiSW 02/I/2007 supported by the Polish Ministry of Science and Higher Education and entitled Uncooled photodetectors from HgCdTe. The paper describes the progress of technology of HgCdTe heterostructures and properties of MWIR and LWIR detectors.
13
Content available remote Surface smoothness improvement of HgCdTe layers grown by MOCVD
EN
This paper presents results of experimental efforts pointed towards morphology improvement of HgCdTe layers grown by MOCVD on GaAs substrates. Selected growth parameters on morphology state are presented. The substrate issues like its quality and crystallographic orientation have been discussed. Also influence of HgCdTe layer thickness on its surface roughness is described. It is shown that extensive characterization studies using accessible equipments and methods: atomic force microscopy (AFM), secondary electron microscopy (SEM), laser scatterometer and Nomarski microscopy, have provided invaluable information about the correlation between defect formation and the influence of specific growth parameters.
14
Content available remote Badania eksperymentalne procesu fragmentacji węgla w powietrzu wzbogaconym tlenem
PL
W procesie spalania paliw stałych następuje rozpad ziaren węgla na mniejsze fragmenty. Podczas rozpadu ziarna węgla następuje skokowy wzrost powierzchni spalania, co prowadzi do skrócenia całkowitego czasu spalania ziarna oraz poprawy skuteczności spalania, poprzez lepszą wymianę masy i ciepła. W artykule określono mechanizmy procesu fragmentacji ziaren węgla podczas spalania w atmosferze wzbogaconej tlenem. Wyznaczono również prawdopodobieństwo i stopień fragmentacji pierwotnej oraz wtórnej dla czterech różnych typów węgli oraz przeanalizowano wpływ temperatury w komorze paleniskowej i średnicy ziarna na proces termicznego rozpadu.
EN
Brown and hard coal particles undergo fragmentation during combustion process i.e. the decomposition of coal into a small pieces. It causes increase of combustion surface and accelerates combustion process. Results of experimental investigations of thermal fragmentation for four different types of coals during oxygen-enriched air combustion are presented in this paper. Probability and degree of fragmentation are determined. The effects of coal rank, temperature in combustion chamber and particle size on fragmentation have been also determined.
EN
The combustion of coal in mixture of pure O2 and recycled flue gas is one variant of a novel combustion approach called oxy-fuel combustion. Conventional boilers use air for combustion in which the nitrogen from the air (approximately 79% by volume) dilutes the CO2 concentration in the flue gas. The capture of carbon dioxide from such dilute mixtures using amine stripping is relatively expensive. The recycled flue gases mainly consist of CO2 and H2O and are used to create combustion conditions similar to those of air. Spherical coal particles of 10 mm in diameter were combusted in the mixtures of O2/CO2 in a 10 kW bench scale unit at a temperature of 700-85O°C.
PL
Artykuł przedstawia wyniki prac badawczych uzyskanych w Vigo System S.A. i Instytucie Fizyki Technicznej Wojskowej Akademii Technicznej w ramach realizacji zadania nr 5.1 PBZ-MiN-009/T11/2003 pt.: Opracowanie i wykonanie niechłodzonych i minimalnie chłodzonych detektorów średniej i dalekiej podczerwieni nowej generacji. W ramach tej pracy opracowano technologie i przebadano właściwości dwu klas detektorów: detektorów do spektroskopii Fouriera zakresu 3...16 mm i detektorów do szerokopasmowej (1 Gb/s) łączności optycznej w otwartej przestrzeni.
EN
This article presents scientific results of works carried out in VIGO System S.A. and Institute of Applied Physics Military University of Technology, accomplished during realization of grant 5.1 PBZ-MiN-009/T11 /2003 supported by the Polish Ministry of Science and Higher Education and entitled Elaboration and realization of new generation near room temperature middle- and long-wavelength infrared detectors. The paper describes the technology and properties of two types of detectors: photodetectors for Fourier spectroscopy and photodetectors for wide band optical space communication.
PL
Od 2003 r. w laboratorium VIGO/WAT prowadzono badania nad wzrostem heterostruktur Hg1-xCdxTe o niemal dowolnych profilach składu i poziomie domieszkowania, niezbędnych dla zaawansowanych przyrządów fotoelektrycznych. MOCVD w zastosowaniu do Hg1-xCdxTe jest jedną znajtrudniejszych technologii epitaksjalnych. Omówiono zagadnienia związane ze wzrostem i charakteryzacją warstw Hg1-xCdxTe w technologii MOCVD. Dokonano pomiarów insitu względnego stężenia związków metaloorganicznych analizatorem gazu własnej konstrukcji. Podsumowano stan domieszkowania warstw Hg1-xCdxTe z uwzględnieniem ostatnich badań. Opracowana technologia MOCVD została zastosowana do otrzymywania wszystkich typów produkowanych w VIGO System detektorów podczerwieni pracujących w temperaturach pokojowych.
EN
Since 2003 VIGO System S.A. together with MUT (Military University of Technology) are doing joint efforts to improve MOCVD growth of Hg1-xCdxTe. Photodetectors optimized for any wavelength within 1-15 um spectral range requires complex heterostructures with multiple layers with homogeneous composition and doping, characterized by steep interfaces. Hg1-xCdxTe growth with interdiffused multilayer process (IMP) technique has been improved using self-made in-situ monitoring of gas delivery to the growth zone. The other issues addressed in this work were growth of heavy As-doped low-x and heavy l-doped high-x materials. Special modification to IMP process has been applied for in-situ control of stoichiometry. To maintain low vacancy concentration, special growth finish procedure has been developed. No post-growth thermal anneal was necessary for device-quality material. The MOCVD grown heterostructures have been successfully used for advanced uncooled infrared photodetectors such as multiple heterojunction photodiodes, multicolor and multiabsorber devices with specially shaped spectral response.
18
Content available remote Growth and properties of MOCVD HgCdTe epilayers on GaAs substrates
EN
Growth of MOCVD Hg1-xCdxTe (HgCdTe) epilayers on GaAs substrates is described. The paper focuses on the interdiffused multilayer process (IMP). In this process, the CdTe/HgTe growth times are comparable with transition times between the phases. The non-optimum flow velocities and partial pressures that may induce poor morphology and reduce growth rate characterize the growth during transition stages. The optimum conditions for the growth of single layers and complex multilayer heterostructures have been established. One of the crucial stages of HgCdTe epitaxy is CdTe nucleation on GaAs substrate. Successful composite substrates have been obtained with suitable substrate preparation, liner and susceptor treatment, proper control of background fluxes and appropriate nucleation conditions. Due to the large mismatch between GaAs and CdTe, both (100) and (111) growth may occur. It mostly depends on substrate disorientation and preparation, nucleation conditions and growth temperature. Cd or Te substrate treatment just before growth results in (100) and (111) orientation, respectively. Generally, layers with orientation (100) show superior morphology compared to (111) but they are also characterized by hillocks. The benefits of the precursors ethyl iodine (EI) and arsine (AsH3) for controlled iodine donor doping and arsenic acceptor doping are summarized. Suitable growth conditions and post growth anneal is essential for stable and reproducible doping. In-situ anneal seems to be sufficient for iodine doping at any required level. In contrast, efficient As doping with near 100% activation requires ex-situ anneal at near saturated mercury vapours. The transport properties of HgCdTe epilayers indicate on achieving device quality material. Reproducible n- and p-type doping at the low, intermediate and high level (1015-1018 cm-3) has been achieved with stable iodine and arsenic dopants. The mobilities and carrier lifetimes achieved for extrinsically doped n-type and p-type layers follow essentially the same trends observed in state-of-the-art liquid phase epitaxy grown HgCdTe.
19
Content available remote Growth of MOCVD HgCdTe heterostructures for uncooled infrared photodetectors
EN
In the paper recent progress at VIGO/MUT (Military University of Technology) MOCVD Laboratory in the growth of Hg1-xCdx Te (HgCdTe) multilayer heterostructures on GaAs/CdTe substrates is presented. The optimum conditions for the growth of single layers and complex multilayer heterostructures have been established. One of the crucial stages of HgCdTe epitaxy is CdTe nucleation on GaAs substrate. Successful composite substrates have been obtained with suitable substrate preparation, liner and susceptor treatment, proper control of background fluxes and appropriate nucleation conditions. The other critical stage is the interdiffused multilayer process (IMP). The growth of device-quality HgCdTe heterostructures requires complete homogenization of CdTe-HgTe pairs preserving at the same time suitable sharpness of composition and doping profiles. This requires for IMP pairs to be very thin and grown in a short time. Arsenic and iodine have been used for acceptor and donor doping. Suitable growth conditions and post growth anneal is essential for stable and reproducible doping. In situ anneal seems to be sufficient for iodine doping at any required level. In contrast, efficient As doping with near 100% activation requires ex situ anneal at near saturated mercury vapours. As a result we are able to grow multilayer fully doped (100) and (111) heterostructures for various infrared devices including photoconductors, photo electromagnetic and photovoltaic detectors. The present generation of uncooled long wavelength infrared devices is based on multijunction photovoltaic devices. The technology steps in fabrication of devices are described. It is shown that near-BLIP performance is possible to achieve at c.a 230 K with optical immersion. These devices are especially promising as 7.8-9.5-J-[mu]m detectors, indicating the potential for achieving detectivities above 10 do potęgi 9 cmHz1/2/W.
20
EN
We report here recent progress at VIGO/WAT MOCVD Laboratory in the growth of Hg₁₋xCdxTe (HgCdTe) multilayer heterostructures on GaAs/CdTe and other composite substrates for uncooled infrared photodetectors. The optimum conditions for the growth of single layers and complex multilayer heterostructures have been established. One of the crucial stages of the technology was CdTe nucleation on GaAs substrate. Successful composite substrates were obtained with suitable substrate preparation, liner and susceptor treatment, proper control of background fluxes and appropriate nucleation conditions. The other critical stage is the interdiffused multilayer process (IMP). The growth of device-quality HgCdTe heterostructures requires complete homogenization of CdTe-HgTe pairs preserving at the same time suitable sharpness of composition and doping profiles. This requires for IMP pairs to be very thin and grown in a short time. The practical implications for the IMP process are the CdTe/HgTe growth times that become comparable with transition times between the phases, characteristic for the MOCVD machine. The growth during transition stages is characterized by the non-optimum flow velocities and partial pressures that may induce poor morphology, reduce growth rate and cause other problems. This became especially acute for doped layers when large Cd/Te ratio is required for efficient incorporation and full activation of dopants. This has been solved by careful selection of hydrogen carrier gas and metaloorganics fluxes with suitable switching on and off times. Arsenic and iodine has been used for acceptor and donor doping. Suitable growth conditions and post growth anneal is essential for stable and reproducible doping. In-situ anneal seems to be sufficient for iodine doping at any required level. In contrast, efficient As doping with near 100% activation requires ex situ anneal at near saturated mercury vapors. As the result, we are able to grow multilayer fully doped (100) and (111) heterostructures for various infrared devices including photoconductors, photoelectromagnetic and photovoltaic detectors.
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