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Tytuł:
Influence of AlN spacer on the properties of AlGaN/AlN/GaN heterostructures
Autorzy:
Wosko, M
Paszkiewicz, B
Paszkiewicz, R
Tlaczala, M
Powiązania:
https://bibliotekanauki.pl/articles/174100.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
AlGaN/GaN
heterostructure
AlN spacer
MOVPE
Opis:
AlGaN/GaN heterostructures attract attention of many research groups over the last decade because of their superior properties (high mobility and saturation velocity of 2DEG) and strong capability in high frequency/power electronics and sensors applications. One of the factors which reduces the mobility of two-dimensional electron gas (2DEG) is the alloy and interface roughness scattering mechanism occurring at the heterointerface. Mathematical calculations of a wave-function of 2DEG in the channel show that theses two phenomena play an important role, due to the fact that some electrons in 2DEG can migrate into AlGaN barrier and be strongly dissipated. One of the proposed solutions against alloy scattering in the buffer layer is the use of thin AlN spacer at the heterointerface between AlGaN and GaN layers. AlN layer enhances the conduction band offset due to a polarization-induced dipole in the AlN layer, and therefore increases carrier confinement. Several Al0.18GaN0.82/AlN/GaN heterostructures with different AlN spacer layer thickness were grown by MOVPE method for studies of the Hall mobility and sheet carrier concentration of 2DEG. Hall measurements performed using Van der Pauw shown mobility maximum at nominally 1.3 nm AlN spacer thickness and almost linear dependence of sheet carrier concentration with AlN spacer thickness in the range from 0.7 to 2 nm.
Źródło:
Optica Applicata; 2013, 43, 1; 61-66
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-stage Reimplantation in Infected Total Knee Arthroplasty by Using Resterilized Femoral and Tibial Components with a New Polyethylene Insert: Report of 4 Cases with at Least 15 Years’ Follow-up
Autorzy:
Öztürk, Alpaslan
Çevik, Nazan
Akalın, Yavuz
Çetin, Oğuz
Avci, Özgür
Kaya, Ali Ömer
Powiązania:
https://bibliotekanauki.pl/articles/28411803.pdf
Data publikacji:
2021-12-20
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
total knee arthroplasty
periprosthetic infection
articulating spacer
complications
Opis:
Background. This study evaluates 15 years’ results of the implantation of autoclaved femoral and tibial prosthesis components together with a new same brand polyethylene insert which were used as a temporary articulating spacer in patients with periprosthetic infection of total knee arthroplasty (TKA) in a two-stage reimplantation procedure in 6 patients.  Material and methods. The femoral and tibial prostheses of 6 patients with deep chronic periprosthetic infection of TKA who underwent elective two-stage exchange arthroplasty were autoclaved and reinserted with a new polyethylene insert of the same brand and bone cement mixed with tecoplanin in 2004. Results. Four patients were followed for 15 years. They were all female and between 47-70 years old. The infectious agent was meticillin-resistant Staphylococcus aureus (MRSA) in 3 and coagulase negative Staphylococcus in one patient. Patients were invited for second stage reimplantation, but they refused to undergo the second stage. Three of them had their second stage reimplantation after 15, 13 and 10 years while one patient was reinfected after 5 years, in 2009, and arthrodesis was performed. They were all happy with the result and infection free at last follow-up.  Conclusions. 1. Regarding the results of our patients, reinsertion of autoclaved femoral and tibial prostheses together with a new same brand polyethylene insert with teicoplanin loaded bone cement can be used cautiously in the management of periprosthetic deep infection of TKA. 2. That is because patients might not want the second stage reimplantation. 3. We believe that the refusal of patients to undergo the surgery shows that the single-stage treatment is effective.
Źródło:
Ortopedia Traumatologia Rehabilitacja; 2021, 23(6); 411-416
1509-3492
2084-4336
Pojawia się w:
Ortopedia Traumatologia Rehabilitacja
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Process and Design of Jacquard Warp Knitted Spacer Fabric
Autorzy:
Wen, Zhang
Liu, Shuai
Powiązania:
https://bibliotekanauki.pl/articles/2056306.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
warp knitting
jacquard
design pattern
spacer fabric
computer aided design
Opis:
Due to the rapid production of warp knitted jacquard spacer fabric in recent years, as well as physical properties of light, heat conduction, buffering effect, compression resistance, moisture permeability and air permeability, warp knitted spacer fabric has been used more and more widely in clothing, shoes and hats, as well as in fields such as medical care, construction engineering, safety protection and others. The design demand for different patterns and functions is also increasing gradually. Jacquard designers established a complete design model which plays a certain guiding role in the design of warp knitted spacer fabric. It brings innovative design to the surface pattern and structure of the fabric, making it more functional. The adoption of computer aided design also has a certain guiding role in the design process. Taking the CAD pattern design of warp knitted spacer fabric as an example, which combines the functional characteristics of the fabric and the jacquard pattern. Thus, we design fabric products that meet the market demand and initiate fashion trends.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 1 (151); 67--70
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of medicinal plant Schisandra chinensis using a potential DNA barcode ITS2
Autorzy:
Li, X.-K.
Wang, B.
Han, R.-C.
Zheng, Y.-C.
Yin, H.-B.
Xu, L.
Zhang, J.-K.
Xu, B.-L.
Powiązania:
https://bibliotekanauki.pl/articles/56996.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
identification
internal transcribed spacer
medicinal plant
Schisandra chinensis
DNA barcode
Opis:
To test whether the internal transcribed spacer 2 (ITS2) region is an effective marker for using in authenticating of the Schisandra chinensis at the species and population levels, separately. And the results showed that the wild populations had higher percentage of individuals that had substitution of C→A at site 86-bp than the cultivated populations. At sites 10-bp, 37-bp, 42-bp and 235-bp, these bases of the Schisandra sphenanthera samples differed from that of S. chinensis. Two species showed higher levels of inter-specific divergence than intra-specific divergence within ITS2 sequences. However, 24 populations did not demonstrate much difference as inter-specific and intra-specific divergences were concerned. Both S. chinensis and S. sphenanthera showed monophyly at species level, yet the samples of different populations shown polyphyly at population level. ITS2 performed well when using BLAST1 method. ITS2 obtained 100% identification success rates at the species level for S. chinensis, with no ambiguous identification at the genus level for ITS2 alone. The ITS2 region could be used to identify S. chinensis and S. sphenanthera in the “Chinese Pharmacopoeia”. And it could also correctly distinguish 100% of species and 100% of genera from the 193 sequences of S. chinensis. Hence, the ITS2 is a powerful and efficient tool for species identification of S. chinensis.
Źródło:
Acta Societatis Botanicorum Poloniae; 2013, 82, 4
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The research and analysis of the bactericidal properties of the spacer knitted fabric with the UV-C system
Autorzy:
Łada-Tondyra, Ewa
Jakubas, Adam
Jabłońska, Beata
Stańczyk-Mazanek, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/2063894.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
fibre optics
sterilization
textronics
ultraviolet radiation
warp-knitted spacer fabrics
Opis:
The research and analysis of the bactericidal properties of the spacer knitted fabric with the UV-C system are presented in this paper. The disintegration factor affecting the bacteria in the knitted fabric is the UV-C radiation in the range of 265–270 nm distributed via woven optical fibres. The way of integrating elements of the system generating the UV-C radiation in the structure of the spacer knitted fabric was designed, as well as various configurations of optical fibres arrangement, fibre density, number of radiation sources, and diode types were tested. The material was contaminated with selected microorganisms indicative of sanitary contamination and important in terms of nosocomial infections. The scope of the research included microbiological (quantitative and qualitative) analyses of selected taxonomic groups of microorganisms (mesophilic bacteria, fungi, actinomycetes) before and after the irradiation process. The analysis of the research results and the applied modification of the knitted fabric turned out to be effective in reducing the amount of potentially pathogenic microorganisms.
Źródło:
Opto-Electronics Review; 2021, 29, 4; 192--200
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Video-based technique for damaged spacers detections during power line inspections
Wizyjna technika detekcji uszkodzeń odstępników podczas inspekcji linii energetycznych
Autorzy:
Okarma, K.
Mazurek, P.
Powiązania:
https://bibliotekanauki.pl/articles/153215.pdf
Data publikacji:
2008
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
odstępnik
ekstrakcja cech geometrycznych
detekcja uszkodzeń
spacer
geometrical features' extraction
fault detection
Opis:
In the paper a digital image processing algorithm useful for video-based analysis of power lines spacers' mechanical condition is proposed. For testing purposes the semi-synthetic images of some damaged typical spacers have been used but for the verification of the detection of spacers' location working properties the real images taken from the camera have been used. Presented method is based mainly on the geometrical features' extraction techniques and can be applied in the systems for the analysis of data acquired by e.g. aerial fly-by patrols.
W pracy zaproponowano algorytm cyfrowego przetwarzania obrazów użyteczny w analizie wideo uszkodzeń mechanicznych odstępników w liniach energetycznych. Do celów testowych zostały użyte półsyntetyczne obrazy uszkodzeń typowych odstępników, natomiast weryfikacja działania detekcji położenia odstępników została przeprowadzona w oparciu o obrazy rzeczywiste uzyskane z kamery. Proponowana metoda jest oparta głównie na technikach ekstrakcji cech geometrycznych i może być użyta w systemach automatycznej analizy danych uzyskiwanych np. podczas inspekcji lotniczych.
Źródło:
Pomiary Automatyka Kontrola; 2008, R. 54, nr 10, 10; 677-678
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cotton leaf blight disease caused by Alternaria alternata in Sudan
Autorzy:
Mohamed, O.E.
Beshir, M.M.
Ahmed, N.E.
Powiązania:
https://bibliotekanauki.pl/articles/2084617.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Alternaria alternata
conidia
Gossypium spp.
internal transcribed spacer
(ITS)
morphological variability
pathogenicity
Opis:
Genetically modified Bt cotton (Gossypium hirsutum) leaves with typical symptoms of Alternaria early blight disease resembling that of tomato and potato were observed in the main cotton growing schemes in Sudan. Symptoms on leaves appeared as either brown 2leaf spot with gray centers or leaf blight with concentric rings. Pathogenicity tests using isolates with both symptoms showed that the isolated fungi were highly pathogenic to both G. hirsutum and G. barbadense cotton varieties. Alternaria alternata isolated from infected tomato and potato leaves with early blight symptoms was included for comparison. Microscopic examination showed that the mean length of conidia from cotton, tomato and potato isolates ranged from 26.25 to 45.45 µm, while the width ranged from 9.56 to 13.64 µm. The mean number of transverse septa among all isolates was 3.4 to 5.7 and the peak length ranged from 3.75 to 7.8 µm. Based on morphological characteristics the two isolates from cotton were identified as A. alternata. Genomic DNA was extracted directly from fungal cultures grown on potato dextrose agar (PDA) plates using a Zymo Research Quick DNA kit. A species-specific primer using the internal transcribed spacer ribosomal DNA (ITS rDNA) PCR scoring indicated the presence of A. alternata using primer pair ITS4/ITS5. Amplifications of the internal transcribed spacer region of 600 bp revealed 100% identity of the isolated fungus from cotton with A. alternata from tomato and potato. These data oblige us to reconsider the presence of A. alternata in the four main cotton growing schemes in Sudan while these symptoms have always been described for tomato and potato early blight disease.
Źródło:
Journal of Plant Protection Research; 2019, 59, 3; 412-417
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Obrazy miasta w Pozwól rzece płynąć Michała Cichego. Prolegomena
Autorzy:
Maroszczuk, Grażyna
Powiązania:
https://bibliotekanauki.pl/articles/2030961.pdf
Data publikacji:
2018-12-16
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
city
„nature city”
„walking book”
„peripatetic”
miasto
„miasto przyroda”
„książka spacer”
perypatetyk
Opis:
Michał Cichy is the author of two books Always is today and Let the river flow.The subject of literary reflection of the writer is modern, transient, heterotopic city. Sketch of Grażyna Maroszczuk presents reflections on the literary updating of the city in the metaphor of the “walking book” of peripatetic, observer and resident of Warsaw’s old district of Ochota.
Źródło:
Tematy i Konteksty; 2018, 13, 8; 174-184
2299-8365
Pojawia się w:
Tematy i Konteksty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Babie lato, czyli zmysłowość wiejskiego krajobrazu
Indian summer, or the sensuousness of the rural landscape
Autorzy:
Frydryczak, Beata
Powiązania:
https://bibliotekanauki.pl/articles/2152453.pdf
Data publikacji:
2021-12-15
Wydawca:
Narodowe Centrum Kultury
Tematy:
krajobraz
wiejska okolica
spacer
partycypacja
doznania
landscape
countryside
a walk
participation
experiences
Opis:
This essay offers an analysis of the countryside defined and perceived as an inhabited place but also as a landscape where the visual evolves into a multi-sensory experience. The text is divided into three sections corresponding to three dimensions of the landscape. The aesthetic dimension relates to the visual features of the landscape which determine its aesthetic sense. The participatory dimension comprises the cultural sense that encompasses the meanings inscribed in the landscape as well as the social and historical processes that make the taskspace with its patterns of dwelling activities. The third dimension, whose description is based on Józef Chełmoński’s painting Indian Summer, is represented by the embodied landscape defined by the polysensory features and tactility playing the primary role (the landscape can be ‘touched’). These three dimensions show how the relationship between humans and the landscape can change in two differing situations: when humans adopt a distanced attitude of viewers or that of participants who enter the landscape and shape it not only physically and symbolically, but also in the sensory dimension.
Źródło:
Kultura Współczesna. Teoria. Interpretacje. Praktyka; 2021, 116, 4; 119-130
1230-4808
Pojawia się w:
Kultura Współczesna. Teoria. Interpretacje. Praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research into the development of a hybrid spacer
Autorzy:
Kremieniewski, Marcin
Kędzierski, Miłosz
Powiązania:
https://bibliotekanauki.pl/articles/1834097.pdf
Data publikacji:
2020
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
hybrydowa ciecz buforowa
bufor
ciecz wyprzedzająca
oczyszczenie przestrzeni pierścieniowej
poprawa skuteczności
zacementowania
ciecz dwufunkcyjna
hybrid spacer
spacer
preflushes
cleaning of the annular space
improvement of cementing efficiency
bifunctional liquid
Opis:
While the cement slurry is being pumped, the drilling mud is removed in the annular space filled with it. The cement slurry pressed after the mud removes residues of mud sludge. In order to properly seal the borehole with cement slurry, which will prevent gas flow after binding, it is necessary to thoroughly clean the annular space from the mud sludge by pumping the sequence of preflush. First, the washing liquid is pumped, then the spacer, followed by the cement slurry. Obtaining a properly cleaned annular space before cementing undoubtedly improves sealing and allows to eliminate or reduce the possibility of the undesirable phenomenon of gas micro flows in the annular space. However, pressing the washing liquid to disperse the residue of the sludge and then pressing the spacer after it, which equalizes the rheological parameters between the pressed drilling fluids (low-viscous washing - cement slurry with much higher plastic viscosity) causes an increase in the costs of cementing. Therefore, it was decided to carry out research on the development of a hybrid spacer. The idea of research was that the spacer had a dual-purpose nature. On the one hand, the hybrid liquid was to act as a spacer (properly selected density, viscosity and structural strength), and on the other hand, the surfactants contained in the spacer were to clean the annular space prepared for cementation. The use of such a liquid reduces costs and shortens the preparation time for cementing. This article presents the results of research on the development of a hybrid spacer. Annular space purification studies were performed under simulated borehole conditions. The obtained research results allowed to state that the developed hybrid spacer has bifunctional properties and an improvement in the cleaning of the rock formation surface is visible compared to the washing liquids used so far. Unfortunately, a problem was also found regarding significant gelation of the mud during contact with the cement present in the spacer. It should be noted that these were pilot studies in which only a partial solution to the problem was achieved. The developed hybrid spacer requires further research to eliminate gelation of the mud during contact with the hybrid spacer. The discussed issue allows researchers themselves to familiarize themselves with the discussed subject, thanks to which in the future it will be possible to further develop given issues.
Źródło:
Nafta-Gaz; 2020, 76, 8; 517-526
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resistance Welding of High-Manganese Cast Steel with Unalloyed Steel Rails
Autorzy:
Tasak, E.
Ziewiec, A.
Tuz, L.
Powiązania:
https://bibliotekanauki.pl/articles/380090.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
crossovers welding
hadfield cast steel
austenite spacer
dissimilar metals welding
zwrotnica
spawanie
staliwo
austenit
Opis:
The paper presents the influence of resistance welding parameters on the mechanical properties and structure of joints of the unalloyed steel rail and high-manganese crossover. As the spacer Cr-Ni austenitic cast steel with decreased austenite stability was used. The results show, that the austenitic cast steel with metastable structure of austenite provide to high strain hardening of spacer deformation during operation. The high increase of hardness is the result dislocation hardening and the transition of austenite into martensite. The content of ferrite &delta and martensite was measured by metallographic method and verified by X-ray diffraction phase analysis. Moreover, it was shown that to high welding parameters causes the cracks in HAZ of manganese iron cast and in the spacer near to fusion line with unalloyed cast steel. The reparation of cracks can be made by welding methods.
Źródło:
Archives of Foundry Engineering; 2014, 14, 1 spec.; 115-120
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problems, limitations, and challenges in species identifcation of Ascomycota members on the basis of ITS regions
Autorzy:
Baturo-Cieśniewska, Anna
Pusz, Wojciech
Patejuk, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/11543330.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
Ascomycota
fungi
internal transcribed spacer
molecular identification
polymerase chain reaction
barcode
rDNA
phylogenetic analysis
Opis:
The internal transcribed spacer (ITS) region is regarded as a formal fungal primary barcode with a high probability of the correct identification for a broad group of fungi. ITS sequences have been widely used to determine many fungal species and analysis of rDNA ITS is still one of the most popular tools used in mycology. However, this region is not equally variable in all groups of fungi; therefore, identification may be problematic and result in ambiguous data, especially in some species-rich genera of Ascomycota. For these reasons, identification based on rDNA ITS is usually complemented by morphological observations and analysis of additional genes. Reliable species identification of Ascomycota members is essential in diagnosing plant diseases, verifying air quality and the effectiveness of agronomic practices, or analyzing relationships between microorganisms. Therefore, the present study aimed to verify, using specific examples, the extent to which ITS sequence analysis is useful in species identification of pathogens and saprobionts from Ascomycota and demonstrate problems related to such identification in practice. We analyzed 105 ITS sequences of isolates originating from air and plant material. Basic local alignment search tool (BLASTn) significantly contributed to the reliable species identification of nearly 80% of isolates such as Arthrinium arundinis, Beauveria bassiana, Boeremia exigua, Cladosporium cladosporioides, Epicoccum nigrum, Nigrospora oryzae, Sclerotinia sclerotiorum, or Sordaria fimicola and members of the genera Alternaria and Trichoderma. However, for most isolates, additional morphological observations, information regarding the isolate origin and, where possible, a PCR with species-specific primers were helpful and complementary. Using our practical approach, we determined that ITS-based species identification and comparative analysis with GenBank sequences significantly helps identifying Ascomycota members. However, in many cases, this should be regarded as suggestive of a taxon because the data usually require the use of additional tools to verify the results of such analysis.
Źródło:
Acta Mycologica; 2020, 55, 1; 5512
0001-625X
2353-074X
Pojawia się w:
Acta Mycologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Occurrence of Ditylenchus destructor Thorne, 1945 on a sand dune of the Baltic Sea
Autorzy:
Dobosz, R.
Rybaczyk-Mydlowska, K.
Winiszewska, G.
Powiązania:
https://bibliotekanauki.pl/articles/2084759.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ammophila arenaria
internal transcribed spacer (ITS)
potato rot nematode
18S
28S rDNA
Opis:
Ditylenchus destructor is a serious pest of numerous economically important plants worldwide. The population of this nematode species was isolated from the root zone of Ammophila arenaria on a Baltic Sea sand dune. This population’s morphological and morphometrical characteristics corresponded to D. destructor data provided so far, except for the stylet knobs’ height (2.1–2.9 vs 1.3–1.8) and their arrangement (laterally vs slightly posteriorly sloping), the length of a hyaline part on the tail end (0.8–1.8 vs 1–2.9), the pharyngeal gland arrangement in relation to the intestine (dorsal or ventral vs dorsal, ventral or lateral) and the appearance of vulval lips (smooth vs annulated). Ribosomal DNA sequence analysis confirmed the identity of D. destructor from a coastal dune.
Źródło:
Journal of Plant Protection Research; 2020, 60, 1; 31-40
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical Properties and Microstructure of Dissimilar Material Welded Joints
Własności mechaniczne i mikrostruktura złączy zgrzewanych materiałów różnorodnych
Autorzy:
Ziewiec, A.
Tasak, E.
Ziewiec, K.
Formowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/352565.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
crossovers
welding
Hadfield cast steel
austenite spacer
zwrotnice
spawanie
staliwo Cr-Ni
metastabilny austenit
Opis:
The paper presents results of the mechanical testing and the microstructure analysis of dissimilar welded joint of the R350HT steel and the high-manganese (Hadfield) cast steel using Cr-Ni cast steel spacer. The simulation tests of the welded joint surface deformation were carried out. The macroscopic and microscopic investigation were made using light microscopy (LM) and scanning electron microscopy (SEM). Content of the magnetic phase was measured using magnetoscope. The quantitative metallographic investigation was used for assessment of ferrite and martensite contents and X-ray diffraction phase analysis was carried out. The results showed that during cooling of the spacer after welding, the transformation of metastable austenite into martensite proceeded. In addition to work hardening, the phase transformation of austenite into martensite occurs during the process of the superficial deformation of the spacer while simulated exploitation. This leads to a substantial increase of hardness, and at the same time, causes the increase of wear resistance of the welded joints of crossovers.
W artykule przedstawiono wyniki badań własności i struktury złącza zgrzewanego stali R350HT ze staliwem wysokomanganowym poprzez przekładkę ze staliwa Cr-Ni. Wykonano symulacyjne procesy odkształcania powierzchni złącza. Przeprowadzono badania makrostrukturalne, mikrostrukturalne LM i SEM, zawartości fazy magnetycznej magnetoskopem, metalograficzną ilościową ocenę martenzytu i ferrytu oraz analizę fazową XRD. Badaniawykazały, że w przekładce podczas chłodzenia po zgrzewaniu występuje przemiana metastabilnego austenitu w martenzyt. Równocześnie w procesie powierzchniowego odkształcania przekładki podczas symulowanej eksploatacji oprócz umocnienia zgniotem zachodzi przemiana austenitu w martenzyt. Prowadzi to do znacznego wzrostu twardości a zatem odporności na zużycie toczne złącza zgrzewanego rozjazdu kolejowego.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 3; 911-918
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 35

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