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Wyświetlanie 1-48 z 48
Tytuł:
Airflow Characteristics during the Rotor Spun Composite Yarn Spinning Process
Charakterystyka przepływu powietrza podczas przędzenia przędzy kompozytowej
Autorzy:
Yang, R.
Gao, W.
Xue, Y.
Powiązania:
https://bibliotekanauki.pl/articles/232164.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
rotor-spun composite yarn
simulation
airflow
performance
przędza kompozytowa
symulacja
przepływ powietrza
Opis:
Rotor spun composite yarn shows compound performances when combined with staple fibres and filaments, such as excellent hand feeling as well as extreme elasticity and strength. Air characteristics including pressure and speed are critical factors of the rotor spun composite yarn spinning process. In this paper, air flow characteristics in a rotor composite yarn spinning unit are simulated and analysed by Ansys, and then verified by experiments. The results show that with the same spinning conditions, static pressure within the filament guide tube is lowest: -9 kPa and in rotor around -5 kPa. The speed of the airstream accelerates from the transfer channel inlet to the outlet, and reaches the largest value of 386 m/s at the outlet. As the rotor speed increases, the airflow velocity increases; the static pressure decreases; the breaking strength and CV of the composite yarn increase, and the breaking elongation and hairiness decrease according to the experiment results.
Przędza kompozytowa charakteryzuje się doskonałym chwytem, a także wyjątkową elastycznością i wytrzymałością. Charakterystyka przepływu powietrza, w tym ciśnienie i prędkość, są czynnikami decydującymi o przędzeniu przędzy kompozytowej na przędzarce rotorowej. W artykule przeprowadzono stymulację i analizę charakterystyk przepływu powietrza, a następnie wyniki zweryfikowano eksperymentalnie. Prędkość strumienia powietrza przyspiesza od wlotu kanału przenoszenia do wylotu i osiąga największą wartość 386 m/s na wylocie. Gdy prędkość wirnika wzrasta, prędkość przepływu powietrza również wzrasta, a ciśnienie statyczne maleje, natomiast wytrzymałość na zerwanie przędzy kompozytowej wzrasta.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 5 (125); 13-17
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear piezo-thermoelastic shell theory applied to control of variable-geometry shells
Autorzy:
Tzou, H. S.
Yang, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/279711.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
geometric nonlinearity
smart structures
structronics
von Karman nonlinearity
Opis:
Complexity of multi-field opto-electromechanical coupling always poses many challenging research issues. Recently due to a rapid development in smart structures and structronic systems, multi-field coupling and control of distributed structronic systems also raises variety of new research, development, and system integration issues. This paper presents a generic nonlinear piezo(electric) -thermoelectromechanical shell theory for a piezoelectric double-curvature shell continuum with admissible boundary cinditions. Applications of the generic theory to other shell and non-shell continua based on four system parameters are also demonstrated. Detailed sensing and control electromechanical characteristics are further investigated in a series of shell of various curvatures. The results show that the membrane sensing/control component dominates the lower natutal modes of deep shells and the bending sensing/control component dominates the natural modes of shallow shell. Electromechanical characteristics and effectiveness of distributed sensors and actuators are evaluated.
Zastosowanie nieliniowej piezo-termosprężystej teorii powłok do sterowania powłok o zmiennej geometrii. W pracy przedstawiono zastosowanie ogólnej nieliniowej piezo-termoelektromechanicznej teorii do piezoelektrycznych powłok o podwójnej krzywiźnie oraz czteroparametrowego kontinuum niepowłokowego. Szczegółowo zbadano elektromechaniczne charakterystyki rozłożonego układu pomiarowego i wykonawczego w ciągu powłok o różnej geometrii. Wyniki wskazują, że membranowe elementy pomiarowe i wykonawcze panują nad dynamiką niskich częstości głębokich powłok, a giętne elementy pomiarowe i wykonawcze nadają się do sterowania powłok małowyniosłych. Zbadano elekromechaniczne charakterystyki i efektywność rozłożonych elementów pomiarowych i wykonawczych.
Źródło:
Journal of Theoretical and Applied Mechanics; 2000, 38, 3; 623-644
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous disturbance compensation and Hi/H optimization in fault detection of UAVs
Autorzy:
Liu, H.
Zhong, M.
Yang, R.
Powiązania:
https://bibliotekanauki.pl/articles/331045.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault detection
disturbance compensation
unmanned aerial vehicle
detekcja uszkodzeń
kompensacja zakłóceń
bezzałogowy statek powietrzny
Opis:
This paper deals with the problem of robust fault detection (FD) for an unmanned aerial vehicle (UAV) flight control system (FCS). A nonlinear model to describe the UAV longitudinal motions is introduced, in which multiple sources of disturbances include wind effects, modeling errors and sensor noises are classified into groups. Then the FD problem is formulated as fault detection filter (FDF) design for a kind of nonlinear discrete time varying systems subject to multiple disturbances. In order to achieve robust FD performance against multiple disturbances, simultaneous disturbance compensation and Hi/H optimization are carried out in designing the FDF. The optimality of the proposed FDF is shown in detail. Finally, both simulations and real flight data are applied to validate the proposed method. An improvement of FD performance is achieved compared with the conventional Hi/H-FDF.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2018, 28, 2; 349-362
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on emulsified tyre pyrolysis oil as a coal flotation collector
Autorzy:
Yang, R.
Shen, L.
Wang, H.
Powiązania:
https://bibliotekanauki.pl/articles/109341.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pyrolysis oil
coal flotation
contact angle
interaction heat
adsorption
Opis:
In this paper the possibility of using the pyrolysis oil derived from waste tyres as a collector in flotation of coal was evaluated. The pyrolysis oil was obtained at the initial and final pyrolysis temperatures of 400 and 700 oC, respectively, and the heat holding time of 30 min. Flotation results indicated that the pyrolysis oil emulsion showed stronger collecting ability than diesel and the concentrate ash content just slightly increased in comparison to flotation in the presence of diesel. The contact angle measurement and immersion microcalorimetry test correlated well with the flotation data. The Fourier Transform Infrared Spectroscopy results demonstrated that diesel and pyrolysis oil emulsion is physically adsorbed on the coal surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 279-287
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moving cast shadow detection using block nonnegative matrix factorization
Autorzy:
Yang, X.
Liu, D.
Zhou, D.
Yang, R.
Powiązania:
https://bibliotekanauki.pl/articles/200448.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
moving cast shadow detection
video surveillance
nonnegative matrix factorization
block nonnegative matrix factorization
nadzór wideo
nieujemna faktoryzacja macierzy
Opis:
In recent years, moving cast shadow detection has become a critical challenge in improving the accuracy of moving object detection in video surveillance. In this paper, we propose two novel moving cast shadow detection methods based on nonnegative matrix factorization (NMF) and block nonnegative matrix factorization (BNMF). First, the algorithm of moving cast shadow detection using NMF is given and the key points such as the determination of moving shadow areas and the choice of discriminant function are specified. Then BNMF are introduced so that the new training samples and new classes can be added constantly with lower computational complexity. Finally, the improved shadow detection method is detailed described according to BNMF. The effectiveness of proposed methods is evaluated in various scenes. Experimental results demonstrate that the method achieves high detection rate and outperforms several state-of-the-art methods.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 2; 229-234
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal aging of hydrogenated nitrile rubber – loss of additives and its influence on elasticity maintenance
Starzenie termiczne uwodornionego kauczuku nitrylowego – ubytek dodatków i jego wpływ na zachowanie elastyczności
Autorzy:
Liu, X.
Zhao, J.
Yang, R.
Iervolino, R.
Barbera, S.
Powiązania:
https://bibliotekanauki.pl/articles/945800.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
hydrogenated nitrile rubber
thermal aging
additives
elasticity
uwodorniony kauczuk nitrylowy
starzenie termiczne
dodatki
elastyczność
Opis:
The thermal aging of hydrogenated nitrile rubber (HNBR) at elevated temperatures 125 and 150 °C was investigated. The changes of chemical structures, including functional groups and crosslinking density, and the changes of mechanical properties, including recovery from bending (RFB), tensile strength, elongation at break and Young's modulus, were determined. In addition, the loss of additives was analyzed by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The aging procedure of HNBR exhibited two stages: loss of additives along with the deterioration of elasticity; obvious oxidation and extra crosslinking with further hardening and embrittlement. The relationship between the deterioration of elasticity and the loss of plasticizers was established. It was demonstrated that the failure of HNBR happened long before obvious oxidation and crosslinking of the rubber chains, and the loss of additives, especially the loss of plasticizers, was the main reason for the failure. Therefore, the elasticity recovery of aged HNBR immersed in the plasticizer (n-propyl palmitate as a model) was carried out. This treatment was demonstrated to be effective before obvious oxidation and crosslinking of HNBR occurred during the thermal aging.
Badano starzenie termiczne uwodornionego kauczuku nitrylowego (HNBR) w temperaturze 125 i 150 °C. Określono zmiany struktur chemicznych, w tym grup funkcyjnych i gęstości usieciowania oraz zmiany właściwości mechanicznych, w tym powrotu poodkształceniowego po zginaniu (RFB), wytrzymałości na rozciąganie, wydłużenia przy zerwaniu i modułu Younga. Ponadto metodą pirolitycznej chromatografii gazowej z detekcją mas (Py-GC/MS) analizowano straty dodatków obecnych w kauczuku. Procedura starzenia się HNBR wykazywała dwa etapy: ubytek dodatków wraz z pogorszeniem elastyczności; wyraźne utlenianie i dodatkowe sieciowanie związane z dalszym utwardzaniem i zwiększaniem kruchości. Określono zależność pomiędzy zmniejszaniem się elastyczności a ubytkiem dodatków zmiękczających. Wykazano, że pogorszenie właściwości HNBR następowało znacznie wcześniej niż utlenianie i sieciowanie oraz było spowodowane utratą dodatków, a zwłaszcza plastyfikatorów. W związku z tym przeprowadzono próbę odtworzenia elastyczności starzonych próbek HNBR przez zanurzenie w plastyfikatorze (palmitynian n-propylu jako model). Obróbka ta okazała się skuteczna, pod warunkiem przeprowadzenia jej zanim podczas starzenia termicznego nastąpiło utlenianie i sieciowanie HNBR.
Źródło:
Polimery; 2017, 62, 7-8; 588-598
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability analysis of high-order Hopfield-type neural networks based on a new impulsive differential inequality
Autorzy:
Liu, Y.
Yang, R.
Lu, J.
Wu, B.
Cai, X.
Powiązania:
https://bibliotekanauki.pl/articles/330348.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
impulsive differential inequality
globally exponential stability
high order Hopfield type neural network
nierówność różniczkowa
stabilność wykładnicza
sieć neuronowa Hopfielda
Opis:
This paper is devoted to studying the globally exponential stability of impulsive high-order Hopfield-type neural networks with time-varying delays. In the process of impulsive effect, nonlinear and delayed factors are simultaneously considered. A new impulsive differential inequality is derived based on the Lyapunov–Razumikhin method and some novel stability criteria are then given. These conditions, ensuring the global exponential stability, are simpler and less conservative than some of the previous results. Finally, two numerical examples are given to illustrate the advantages of the obtained results.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 1; 201-211
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inspection optimization model with imperfect maintenance based on a three-stage failure process
Model optymalizacji przeglądów w warunkach niepełnej konserwacji oparty o trójfazowy proces uszkodzenia
Autorzy:
Yang, R.
Zhao, F.
Kang, J.
Li, H.
Teng, H.
Powiązania:
https://bibliotekanauki.pl/articles/1365969.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
delay time modeling
three-stage failure process
inspection
imperfect maintenance
proportional age reduction
Modelowanie metodą czasu zwłoki
trójfazowy proces uszkodzenia
przegląd
konserwacja niepełna
proporcjonalne obniżenie wieku
Opis:
Rolling element bearings are one of the most widely used and vulnerable components in complex systems. The condition monitoring work is very critical for sustaining the system’s availability and reducing the maintenance cost. Shock pulse method (SPM) is a common technique to measure the operating condition of rolling bearings as a three color scheme, e.g., green, yellow and red. This paper proposes an inspection model based on a three-stage failure process which aims to optimize the inspection interval of bearings by minimizing the expected cost per unit time. The three-stage failure process divides the bearings life into three stages before failure: good, minor defective and severe defective stages, corresponding to the three color scheme of SPM. Considering the need to lubricate bearings when the minor defective stage is identified by inspection in industrial applications, we assume that maintenance at the time of inspection identifying the minor defective stage is imperfect. The concept of proportional age reduction is used to model the effect of imperfect maintenance on the instantaneous rates of the minor defective stage, the severe defective stage and failure. Perfect maintenance however is carried out if inspection detects bearings being in the severe defective stage. Failure can be found once it occurs and replacement has to be implemented immediately. Finally, a numerical example is presented to illustrate the effectiveness of the proposed model.
Łożyska toczne są jednymi z najczęściej stosowanych i jednocześnie najbardziej narażonych na uszkodzenia części składowych układów złożonych. Monitorowanie stanu odgrywa bardzo istotną rolę w utrzymaniu dostępności układów i zmniejszeniu kosztów ich obsługi. Metoda impulsów uderzeniowych (SPM) jest powszechnie stosowaną techniką służącą do pomiaru stanu pracy łożysk tocznych, który reprezentowany jest za pomocą kodu trzech kolorów, na przykład, zielonego, żółtego i czerwonego. W artykule zaproponowano model przeglądów oparty na trójfazowym procesie uszkodzenia, który ma na celu optymalizację częstotliwości przeglądów łożysk poprzez minimalizację oczekiwanych kosztów przypadających na jednostkę czasu. Pojęcie trójfazowego procesu uszkodzenia pozwala podzielić żywotność łożyska na trzy fazy przed wystąpieniem uszkodzenia: fazę dobrego stanu, fazę drobnych defektów i fazę poważnych defektów. Podział ten odpowiada kodowi trzech kolorów SPM. Biorąc pod uwagę konieczność smarowania łożysk po zdiagnozowaniu, podczas przeglądu w warunkach przemysłowych, wystąpienia fazy drobnych defektów, zakładamy, że konserwacja w czasie takiego przeglądu jest konserwacją niepełną. Koncepcja proporcjonalnego obniżenia wieku służy do modelowania wpływu niepełnej konserwacji na chwilowe wartości intensywności fazy drobnych defektów, fazy poważnych defektów oraz uszkodzeń. Gdy podczas przeglądu stwierdzi się, że łożysko jest w fazie poważnych defektów, przeprowadza się pełną konserwację. Uszkodzenie zostaje wykryte zaraz po jego wystąpieniu, i wtedy należy dokonać natychmiastowej wymiany łożyska. Pod koniec artykułu, przedstawiono przykład numeryczny, który ilustruje wydajność proponowanego modelu.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 2; 165-173
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-isothermal Decomposition Kinetics of 1-Amino-1,2,3-triazolium Nitrate
Autorzy:
Du, X.-J.
Zou, M.-S.
Li, X.-D.
Yang, R.-J.
Powiązania:
https://bibliotekanauki.pl/articles/358020.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
1-amino-1,2,3-triazolium nitrate
thermal decomposition
TG
non-isothermal kinetics
compensating effect
Opis:
The thermal decomposition kinetics of 1-amino-1,2,3-triazolium nitrate (ATZ-NO3) was investigated by non-isothermal TG-DTG at various heating rates (2, 5, 10, 15, and 20 °C∙min-1). The results showed that the thermal decomposition of ATZ-NO3 consists of two mass-loss stages. The first mass-loss stage corresponds to the loss of nitrate anion and the substituent group, while the second stage corresponds to the splitting of the triazole ring. The kinetic triplets of the two stages were described by a three-step method. Firstly, the Kissinger and Ozawa methods were used to calculate the apparent activation energies (E) and pre-exponential factors (A) of the two decomposition stages. Secondly, two calculation methods (the Šatava-Šesták and Achar methods) were used to obtain several probable decomposition mechanism functions. Thirdly, three assessment methods (the Šatava, double-extrapolation, and the Popescu methods) were used to confirm the most probable decomposition mechanism functions. The reaction models for both stages are random-into-nuclear and random-growth mechanisms, with n = 3/2 for the first stage and n = 1/3, m = 3 for the second stage. The kinetic equations for the two decomposition stages of ATZ-NO3 may be expressed as [wzór]. Mathematical expressions for the kinetic compensation effect were derived.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 1; 99-114
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Feature extraction of molten pool for laser welding quality real-time inspection
Autorzy:
Zhang, J
Yin, H
Huang, H
Yang, R
Yang, J
Li, Y
Powiązania:
https://bibliotekanauki.pl/articles/173597.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
laser materials processing
process monitoring and control
image analysis
Opis:
This paper proposed an image feature extraction method for laser welding molten pool inspection based on cellular neural network. TC4 titanium alloy thin plates were welded by Nd:YAG pulsed laser. A coaxial machine vision system was designed to acquire molten pool images. An auxiliary lighting source was employed to improve the molten pool image quality. By analyzing molten pool images, the welding defects such as fenestration or insufficient depth were identified. These results can be used as a feedback signal for laser power control. Experimental results showed that the proposed method can be used to improve laser welding quality.
Źródło:
Optica Applicata; 2015, 45, 4; 523-533
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft-sediment deformation structures in cores from lacustrine slurry deposits of the Late Triassic Yanchang Fm. (central China)
Autorzy:
Yang, R.
van Loon, A. J.
Yin, W.
Fan, A.
Han, Z.
Powiązania:
https://bibliotekanauki.pl/articles/94445.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
soft-sediment deformation structures
low-density gravity-flow deposits
Triassic
lacustrine sediments
Ordos basin
China
struktury deformacji
osady miękkie
złoża grawitacyjne o niskiej gęstości
trias
osady jeziorne
zlewnia
Ordos
Chiny
Opis:
The fine-grained autochthonous sedimentation in the deep part of a Late Triassic lake was frequently interrupted by gravity-induced mass flows. Some of these mass flows were so rich in water that they must have represented slurries. This can be deduced from the soft-sediment deformation structures that abound in cores from these lacustrine deposits which constitute the Yanchang Fm., which is present in the Ordos Basin (central China). The flows and the resulting SSDS were probably triggered by earthquakes, volcanic eruptions, shear stress of gravity flows, and/or the sudden release of overburden-induced excess pore-fluid pressure. The tectonically active setting, the depositional slope and the high sedimentation rate facilitated the development of soft-sediment deformations, which consist mainly of load casts and associated structures such as pseudonodules and flame structures. Sediments with such deformations were occasionally eroded by slurries and became embedded in their deposits.
Źródło:
Geologos; 2016, 22, 3; 201-211
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New dinosaur egg material from Yunxian, Hubei Province, China resolves the classification of dendroolithid eggs
Autorzy:
Zhang, S.
Yang, T.-R.
Li, Z.
Hu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/21925.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The oofamily Dendroolithidae is a distinct group of dinosaur eggs reported from China and Mongolia, which is characterized by branched eggshell units and irregular pore canals. The ootaxonomic inferences, however, were rarely discussed until now. A colonial nesting site was recently uncovered from the Qinglongshan region, Yunxian, Hubei Province, China. More than 30 dendroolithid egg clutches outcrop on the Tumiaoling Hill, including an extremely gigantic clutch containing 77 eggs. All clutches were exposed in the Upper Cretaceous fluvial-deposited Gaogou For mation. In this study, we emend the diagnosis of the oogenus Placoolithus and assign all dendroolithid eggs from the Tumiaoling Hill to a newly emended oospecies Placoolithus tumiaolingensis that shows greatly variable eggshell microstructure. Moreover, our study also disentangles the previous vexing classification of dendroolithid eggs. We conclude that Dendroolithus tumiaolingensis, D. hongzhaiziensis, and Paradendroolithus qinglongshanensis, all of which were previously reported from Yunxian, should be assigned to the newly emended oospecies Placoolithus tumiaolingensis.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive Predictive Control of a Distillation Column
Autorzy:
Yoon, T. W.
Yang, D. R.
Lee, K. S.
Kwon, Y. M.
Powiązania:
https://bibliotekanauki.pl/articles/908309.pdf
Data publikacji:
1999
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
adaptacyjny układ sterowania
sterownik predykcyjny
adaptive control
multivariable predictive controller
distillation column
Opis:
Distillation processes reveal complicated multivariable nonlinear dynamics for which it is difficult to design a high-performance control system. This paper proposes an adaptive control scheme for a distillation column. The proposed adaptive system consists of a multivariable receding-horizon predictive controller using a transfer function model and a recursive least-squares (RLS) based estimator. Simulations show a consistent closed-loop performance despite the uncertain nonlinear characteristics of the distillation column.
Źródło:
International Journal of Applied Mathematics and Computer Science; 1999, 9, 1; 193-206
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reconstruction of oviraptorid clutches illuminates their unique nesting biology
Autorzy:
Yang, T.-R.
Wiemann, J.
Xu, L.
Cheng, Y.-N.
Wu, X.-C.
Sander, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/19933.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Oviraptorosaurs, a group of non-avian theropod dinosaurs from the Cretaceous of Asia and North America, left behind the most abundant and informative fossil evidence of dinosaur reproductive biology. Previous studies had suggested that oviraptorosaur reproductive biology represents an intermediate stage and exhibited unique modern avian traits. For instance, the adult-associated clutches were predominantly considered as evidence for brooding/thermoregulatory contact incubation (TCI) behaviors, whereas the hypotheses of laying or protection were neglected. Despite numerous oviraptorid egg clutches uncovered from China and Mongolia, their nest architecture and clutch arrangement were rarely investigated in detail. Here we present a comprehensive reconstruction of an oviraptorid clutch based on five new oviraptorid clutches from Jiangxi Province, China. A detailed examination of the new clutches reveals a partially-open oviraptorid nest that contains 3–4 rings of paired eggs (more than 15 pairs total) whose blunt end points toward the center devoid of eggs at an angle of 35–40°. Our detailed three-dimensional reconstruction indicates that the oviraptorid clutch has a unique architecture unknown from extant bird clutches, implying an apomorphic nesting mode. Such a unique nest architecture further contradicts the TCI hypothesis in oviraptorids, hindering sufficient heat transfer to the inner (lower) ring(s) of eggs. Moreover, the size of the new oviraptorid clutches (>30 eggs) is significantly larger than that of the adult-associated clutches (<22 eggs), raising the alternative hypothesis that the adult-associated clutches were uncompleted. This clue thus supports the hypothesis that the clutch-associated oviraptorid adults possibly represent females after an oviposition before a catastrophic sandstorm/flooding burial.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability and dissipativity analysis for neutral type stochastic Markovian jump static neural networks with time delays
Autorzy:
Cao, Yang
Samidurai, R.
Sriraman, R.
Powiązania:
https://bibliotekanauki.pl/articles/91527.pdf
Data publikacji:
2019
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
static neural networks
dissipativity analysis
Markovian jump
time-varying delays
Opis:
This paper studies the global asymptotic stability and dissipativity problem for a class of neutral type stochastic Markovian Jump Static Neural Networks (NTSMJSNNs) with time-varying delays. By constructing an appropriate Lyapunov-Krasovskii Functional (LKF) with some augmented delay-dependent terms and by using integral inequalities to bound the derivative of the integral terms, some new sufficient conditions have been obtained, which ensure that the global asymptotic stability in the mean square. The results obtained in this paper are expressed in terms of Strict Linear Matrix Inequalities (LMIs), whose feasible solutions can be verified by effective MATLAB LMI control toolbox. Finally, examples and simulations are given to show the validity and advantages of the proposed results.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2019, 9, 3; 189-204
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects on the Stability of the Balloon Shape in the Covered Yarn Process
Parametry wpływające na trwałość kształtu balonu w procesie przędzenia z owijaniem
Autorzy:
Feng, P.
Zhang, R.
Yang, C.
Powiązania:
https://bibliotekanauki.pl/articles/234274.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
balloon shape
covered yarn
numerical simulation
parameters
kształt balonu
model matematyczny balonu
przędza poliamidowa
symulacja numeryczna
Opis:
In the process of producing covered yarn, a single outer wrapping yarn forms a balloon when it rotates at high speed. In this work, we used a mathematical model of a balloon formed by polyamide, which is a common outer wrapping yarn, and verified its feasibility with a group of experimental data. The effects of yarn tension, rotation speed, balloon height and turntable radius on the balloon shape were analysed and the correctness simultaneously demonstrated.
W procesie przędzenia z owijaniem, przędza owijająca obracając się z dużą prędkością tworzy balon. W pracy wykorzystano model matematyczny balonu utworzonego z poliamidowej przędzy owijającej i zweryfikowano jego wykonalność z grupą danych eksperymentalnych. Analizowano wpływ naprężeń przędzy, prędkości obrotowej, wysokości balonu i promienia stołu obrotowego na kształt balonu. Przedstawione wyniki mogą być podstawą do wyboru odpowiednich parametrów i uzyskania optymalnego kształtu balonu.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 3 (123); 68-72
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Chest Injury Mechanism Caused by Different Seatbelt Loads in Frontal Impact
Autorzy:
Xiao, S.
Yang, J.
Crandall, J. R.
Powiązania:
https://bibliotekanauki.pl/articles/306880.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
model ciała człowieka
FEM
kinematyka
klatka piersiowa
seatbelt restraint system
human body finite element model
kinematics
rib fractures
chest deflections
Opis:
The purpose of this quantitative study is to investigate the differences of the injury mechanism caused by two different types of seatbelts loads on the occupant chest. Methods: The finite element analysis is employed to compare the different responses of the human body model, including the comparison of kinematics, chest accelerations, seatbelt forces and chest injury outcomes regrading chest deflections and rib fractures. Results: The calculated rib strain/stress from simulations in force-limiting seatbelt are higher than that in the regular seatbelt. The forward movement and torso twist are both great in simulations with force-limiting seatbelt. Meanwhile, there are obvious differences in the injury outcomes of chest deflections and rib fracture risks under the different seatbelt loads. Conclusion: Results indicate the chest deflections and rib fracture risks are negatively correlated under the load of the force-limiting seatbelt, However, they are positively correlated to and determined by the seatbelt peak load of the regular seatbelt. This paper can provide a reference for study of the chest injury mechanism and the protection efficiency of seatbelt.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 3; 53-62
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytic Equation of State and Thermodynamic Properties, for α-, β-, and γ-Si₃N₄ Based on Analytic Mean Field Approach
Autorzy:
Wang, L.
Sun, J.
Yang, W.
Tian, R.
Powiązania:
https://bibliotekanauki.pl/articles/1812044.pdf
Data publikacji:
2008-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.10.+h
65.40.-b
61.66.Fn
Opis:
The analytic mean field potential approach is applied to α-, β-, and γ-Si₃N₄. The analytic expressions for the Helmholtz free energy, internal energy, and equation of state were derived. The formalism for the case of the Morse potential is used in this work. Its six potential parameters are determined through fitting the compression experimental data of α-, β-, and γ-Si₃N₄. The calculated compression curves of α-, β-, and γ-Si₃N₄ are in good agreement with the available experimental data. This suggests that the analytic mean field potential approach is a very useful approach to study the thermodynamic properties of Si₃N₄. Furthermore, we predict the variation of the free energy and internal energy with the molar volume at several higher temperatures and calculate the temperature dependence of the molar volume, bulk modulus, thermal expansion coefficient and isochoric heat capacity at zero pressure.
Źródło:
Acta Physica Polonica A; 2008, 114, 4; 807-818
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the number of turns on the performance of permanent magnet synchronous motor
Autorzy:
Qiu, H.
Zhang, Y.
Yang, C.
Yi, R.
Powiązania:
https://bibliotekanauki.pl/articles/200007.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
eddy currents density
losses
PMSM
number of turns
temperature field
Opis:
The current passed by the stator coil of the permanent magnet synchronous motor (PMSM) provides rotating magnetic field, and the number of turns will directly affect the performance of PMSM. In order to analyze its influence on the PMSM performance, a 3 kW, 1500 r/min PMSM is taken as an example, and the 2D transient electromagnetic field model is established. The correctness of the model is verified by comparing the experimental data and calculated data. Firstly, the finite element method (FEM) is used to calculate the electromagnetic field of the PMSM. The performance parameters of the PMSM are obtained. On this basis, the influence of the number of turns on PMSM performance is quantitatively analyzed, including current, no-load back electromotive force (EMF), overload capacity and torque. In addition, the influence of the number of turns on eddy current loss is further studied, and its variation rule is obtained, and the variation mechanism of eddy current loss is revealed. Finally, the temperature field of the PMSM is analyzed by the coupling method of electromagnetic field and temperature field, and the temperature rise law of PMSM is obtained. The analysis of this paper provides reference and practical value for the optimization design of PMSM.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 3; 429-436
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of different rotor magnetic circuit structure on the performance of permanent magnet synchronous motor
Autorzy:
Qiu, H.
Yu, W.
YANG, C.
Yi, R.
Powiązania:
https://bibliotekanauki.pl/articles/141061.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air gap flux density
cogging torque
magnetic circuit structure
overload capacity
permanent magnet synchronous motor
Opis:
In order to compare the performance difference of the permanent magnet synchronous motors (PMSM) with different rotor structure, two kinds of rotor magnetic circuit structure with surface-mounted radial excitation and tangential excitation are designed respectively. By comparing and analyzing the results, the difference of the motor performance was determined. Firstly, based on the finite element method (FEM), the motor electromagnetic field performance was studied, and the magnetic field distribution of the different magnetic circuit structure was obtained. The influence mechanism of the different magnetic circuit structure on the air gap flux density was obtained by using the Fourier theory. Secondly, the cogging torque, output torque and overload capacity of the PMSM with different rotor structure were studied. The effect mechanism of the different rotor structure on the motor output property difference was obtained. The motor prototype with two kinds of rotor structure was manufactured, and the experimental study was carried out. By comparing the experimental data and simulation data, the correctness of the research is verified. This paper lays a foundation for the research on the performance of the PMSM with different magnetic circuit structure.
Źródło:
Archives of Electrical Engineering; 2017, 66, 3; 583-594
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Efficiency Covering Technology for Covered Yarns Production: Equipment and Experimente
Wysokowydajna technologia przędzenia z owijaniem
Autorzy:
Feng, P.
Zhang, R.
Gan, J.
Yang, C.
Powiązania:
https://bibliotekanauki.pl/articles/233138.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
high efficiency
covering technology
covered yarn
rotation speed
low cost
proces teksturowania
przędza poliamidowa
przędzenie z owijaniem
cechy strukturalne przędzy
Opis:
A new covering technology for producing covered yarns is proposed in this article. On a traditional yarn covering machine, a hollow spindle rotates with a bobbin of the outer wrapping yarn. In the new equipment, the turntable rotates with only one single outer wrapping yarn. With a magnetic device, the bobbin of core yarns is suspended in a balloon formed by outer wrapping yarns. The rotation speed of the turntable can reach 40000 rpm. A series of experiments on the new equipment were conducted and some covered yarn samples were obtained. The performance of these samples were tested and compared with that produced by traditional machines.
W artykule zaproponowano nową technologię przędzenia z owijaniem. W eksperymentach zastosowano 5 prędkości obrotowych: 12.000, 20.000, 27.000, 32.000 and 35.000 r.p.m. Przy użyciu mikroskopu porównano otrzymane przędze z przędzami otrzymanymi metodą tradycyjną. Stwierdzono, że tradycyjna przędza była bardziej puszysta, a przędza otrzymana nową metodą charakteryzowała się dobrą równomiernością. Po porównaniu dwóch rodzajów przędz stwierdzono, że równomierność skrętu przędzy uzyskanej nową metodą jest wyższa, ponieważ w nowym sposobie przędzenia zastosowano synchroniczny napęd taśmy, co skutkuje mniejszymi wahaniami prędkości obrotowej.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 3 (123); 73-78
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Notes on the Occurrence of Tintinnid Ciliates, and the Nasselarian Radiolarian Amphimelissa setosa of the Marine Microzooplankton, in the Chukchi Sea (Arctic Ocean) Sampled each August from 2011 to 2020
Autorzy:
Dolan, John R.
Moon, Jong-Kuk
Yang, Eun Jin
Powiązania:
https://bibliotekanauki.pl/articles/2041957.pdf
Data publikacji:
2021-08-05
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Microzooplankton
plankton
tintinnida
radiolaria
polar seas
Opis:
Here we summarize the results from 10 cruises in the Chukchi Sea, in August, each year from 2011 to 2020. Samples for the qualitative analysis of the microzooplankton were obtained from stations located across the Chukchi Sea using a 20µm plankton net. Conditions encountered, in terms of sea ice coverage and chlorophyll concentrations, varied widely from year to year without any obvious relationship with the composition of the microzooplankton assemblage. Examining a total of 242 samples gathered, we found a total of 44 tintinnid species (morphologically distinct forms). Plotting cumulative number of tintinnid species encountered vs cumulative number of samplings gave a typical species accumulation curve showing no sign of saturation suggesting that continued sampling in the Chukchi Sea will likely yield increases in the tintinnid species catalogue. The tintinnid species found ranged widely in lorica opening diameters (LOD) from about 11 µm to 80 µm in diameter. However, the median size of the LOD of the tintinnid assemblages varied little from year to year ranging only from about 30 µm to 40 µm. Most of the forms encountered were found in samples from only 1 or 2 cruises. Very few forms were found every year throughout the 10 years of sampling. These were 5 species of tintinnids (Acanthostomella norvegica, Leprotintinnus pellucidus, Pytchocylis obtusa, Salpingella acuminata, Salpingella faurei) and the nasselarian radiolarian Amphimelissa setosa. Examples of the morphological variability observed among individuals of Acanthostomella norvegica and Pytchocylis obtusa within single samples are shown with some individuals easily confused with forms described as other species are shown. To our knowledge, our data are the most extensive data set on Chukchi Sea microplankton. We provide all of the data recorded, which may serve as a baseline from which to assess changes projected in Arctic Sea systems, in a supplementary data file.
Źródło:
Acta Protozoologica; 2021, 60; 1-11
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying the effect of some parameters on the stability of shallow tunnels
Autorzy:
Abdellah, W. R.
Ali, M. A.
Yang, H.-S.
Powiązania:
https://bibliotekanauki.pl/articles/92102.pdf
Data publikacji:
2018
Wydawca:
Główny Instytut Górnictwa
Tematy:
tunnel shape
rock joint
numerical modelling
stability indicator
kształt tunelu
przełom skał
modelowanie numeryczne
wskaźnik stabilności
Opis:
Several factors have crucial impact on the serviceability of underground openings including: the quality of rock mass; the presence of rock joints and their geometrical properties; the state of in-situ stress ratio; the depth below surface and opening geometry. This paper only investigates the effect of two parameters on the stability of underground shallow tunnels, namely: the presence of rock joints in the rock mass matrix and the shape of the excavation. A series of two-dimensional elasto-plastic finite-element models has been constructed using rock-soil, RS2D, software. Consequently, parametric stability analysis has been conducted for three different tunnel shapes (e.g. circular, square and horseshoe) with/without joint inclusion. Four reference points have been assigned in the tunnel perimeter (e.g. back, sidewalls and floor) to monitor the state of stress-displacement in the rock mass around them. The results indicate that the weak performance of a tunnel opening occurs with a square-shaped opening and when joints exist in the rock mass. In addition, the normal stress along joints sharply drops in the vicinity of a tunnel opening. Moreover, the direction of shear stress is reversed. Thus, it causes inward shear displacement.
Źródło:
Journal of Sustainable Mining; 2018, 17, 1; 20-33
2300-1364
2300-3960
Pojawia się w:
Journal of Sustainable Mining
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability analysis and H control of discrete T–S fuzzy hyperbolic systems
Autorzy:
Duan, R.
Li, J.
Zhang, Y.
Yang, Y.
Chen, G.
Powiązania:
https://bibliotekanauki.pl/articles/331173.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
discrete T–S fuzzy hyperbolic model
parallel distributed compensation
positive diagonally dominant matrices
robust stability
model Takagi-Sugeno
kompensacja rozproszona
sterowanie odporne
Opis:
This paper focuses on the problem of constraint control for a class of discrete-time nonlinear systems. Firstly, a new discrete T–S fuzzy hyperbolic model is proposed to represent a class of discrete-time nonlinear systems. By means of the parallel distributed compensation (PDC) method, a novel asymptotic stabilizing control law with the “soft” constraint property is designed. The main advantage is that the proposed control method may achieve a small control amplitude. Secondly, for an uncertain discrete T–S fuzzy hyperbolic system with external disturbances, by the proposed control method, the robust stability and H performance are developed by using a Lyapunov function, and some sufficient conditions are established through seeking feasible solutions of some linear matrix inequalities (LMIs) to obtain several positive diagonally dominant (PDD) matrices. Finally, the validity and feasibility of the proposed schemes are demonstrated by a numerical example and a Van de Vusse one, and some comparisons of the discrete T–S fuzzy hyperbolic model with the discrete T–S fuzzy linear one are also given to illustrate the advantage of our approach.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2016, 26, 1; 133-145
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Neuromedin S on the proliferation of splenic lymphocytes and the cytokine secretion by pulmonary alveolar macrophages in pigs in vitro
Autorzy:
Lin, R.
Wang, Q.
Qi, B.
Huang, Y.
Yang, G.
Powiązania:
https://bibliotekanauki.pl/articles/30295.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Neuromedin S (NMS), a 36-amino acid neuropeptide, has been found to be involved in the regulation of the endocrine activity. It has been also detected in immune tissues in mammals, what suggests that NMS may play an important role in the regulation of immune response. The aim of this study was to demonstrate the presence of NMS receptor 1 (NMU1R) and effect of NMS in pig splenic lymphocytes (SPLs) and pulmonary alveolar macrophages (PAMs). The presence of NMU1R in pig SPLs and PAMs was respectively confirmed by reverse transcription-polymerase chain reaction (RT-PCR), western blot analysis and immunocytochemical methods. Furthermore, SPL proliferation was analyzed using the 3-(4,5)-dimethyl-thiahiazo-(-2-yl)-3,5-di-phenytetrazoliumromide (MTT) method. Additionally, the secretion of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in PAMs was all measured by enzyme-linked immunosorbent assay (ELISA) kits. In the present study, the results of RT-PCR and western blot analysis revealed that NMU1R mRNA and protein were both expressed in pig SPLs and PAMs, and the immunocytochemical investigations further revealed that the positive signal of NMU1R immunoreactivity was observed in plasma membranes of both SPLs and PAMs. In the in vitro study, we found that at concentrations of 0.001-1000 nM NMS alone or combined with lipopolysaccharide or phytohemagglutinin significantly increased SPL proliferation. Application of ELISA method showed that NMS could induce the secretion of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α in PAMs. These results suggest that NMS can act as a potently positive pro-inflammatory factor and immunomodulatory agent that affects the immune response of immune cells by combining with its receptor NMU1R.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 3
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on recovery of lead, zinc, iron from jarosite residues and simultaneous sulfur fixation by direct reduction
Autorzy:
Wang, Y.
Yang, H.
Zhang, W.
Song, R.
Jiang, B.
Powiązania:
https://bibliotekanauki.pl/articles/110933.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
jarosite
direct reduction
recovery
valuable metal
sulfur fixation
Opis:
Jarosite residues, which are generated in a zinc production plant by a hydrometallurgical process, contain a large amount of valuable metal components. In this study, a method was proposed for the recovery of lead, zinc and iron from the residues and simultaneous sulfur fixation through direct reduction followed by magnetic separation. The influences of the roasting temperature, roasting time and the concentration of SO2 gas in the direct reduction process were researched in detail. Results showed that the volatilization rates of lead, zinc and sulfur were 96.97%, 99.89% and 1.09%, respectively, and the iron metallization rate was 91.97% under optimal reduction conditions; roasting temperature 1523 K for 60 min. The magnetic concentrate with the iron content of 90.59% and recovery rate of 50.87% was obtained from the optimal reduction product by grinding and magnetic separation. The optimum fineness for separation 96.56% less than 37 μm accounted with magnetic field strength 24 kA/m. The theoretical analysis was carried out by thermodynamics, X-ray powder diffraction, gas analysis and scanning electron microscopy.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 517-526
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical investigations on dynamic tensile behavior of a ZrB2-SiC ceramic
Autorzy:
He, R.
Cao, J.
Yang, K.
Wang, L.
Kong, D.
Powiązania:
https://bibliotekanauki.pl/articles/38695710.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
ZrB2-SiC ceramic
dynamic tensile properties
fracture pattern
strain rate
peridynamic model
Opis:
The dynamic tensile behavior of a ZrB2-SiC ceramic was investigated via split Hopkinson pressure bar tests and a bond-based peridynamic model. The experimental results showed that the peak dynamic splitting tensile stress increased linearly with the strain rate. The dynamic tensile stress history and fracture pattern exhibited a significant strain-rate dependence. In simulation, the strain-rate dependent on the critical energy release rate was introduced to predict the dynamic tensile behavior of the ZrB2-SiC ceramic. The numerical results were in good agreement with the experimental results, verifying the applicability of the peridynamic model. The maximum error of the peak dynamic splitting tensile stress between the experimental and numerical results was no greater than 6%. Moreover, the effect of the strain rate on the fracture patterns of the ZrB2-SiC ceramic composite can be well predicted by the peridynamics method. The ZrB2-SiC composite specimen split into two large fragments with additional small fragments under dynamic splitting tension. With the increase of strain rate, the main crack propagation and branching led to a larger fracture region in the middle of the specimen.
Źródło:
Archives of Mechanics; 2023, 75, 1-2; 53-73
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microzooplankton in a Warming Arctic: A Comparison of Tintinnids and Radiolarians from Summer 2011 and 2012 in the Chukchi Sea
Autorzy:
Dolan, John R.
Yang, Eun Jin
Kim, Tae Wan
Kang, Sung-Ho
Powiązania:
https://bibliotekanauki.pl/articles/763780.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Climate change, plankton, rhizaria, sea ice, Tintinnina
Opis:
The Chukchi Sea was sampled in August of 2011, a year of near-normal sea ice among recent years, and again in August 2012, a year of all time record low sea ice. We exploited this sampling to test the hypothesis that different sea ice conditions are associated with differences in abundances or species composition of microzooplankton through an examination of tintinnids and radiolarians. From 18 stations in 2011, and 19 stations in 2012, organisms were enumerated in plankton net tow material, and chlorophyll determinations made (total and ≤ 20 μm) from discrete depth samples. We found that the low sea ice conditions of 2012 were associated with higher chlorophyll concentrations (both total and the ≤ 20 μm size fraction), compared to 2011. However, tintinnid ciliates and radiolarians were much lower in concentration, by about an order of magnitude, compared to 2011. In both years the radiolarian assemblage was dominated by Amphiselma setosa. The species composition of the tintinnid ciliates was similar in the two years, but there were distinct differences in the relative abundances of certain species. The 2012, low sea ice assemblage, was dominated by small forms in contrast to 2011, when large species were the most abundant. We present these findings in detail and discuss possible explanations for the apparent differences in the microzooplankton communities associated with distinct sea ice conditions in the Chukchi Sea.
Źródło:
Acta Protozoologica; 2014, 53, 1
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Characterization and Compatibility Studies of Poly(DFAMO/NIMMO) with Propellant and PBX Ingredients
Autorzy:
Li, H.
Yang, Y.
Pan, J.
Wang, W.
Pan, R.
Zhu, W.
Powiązania:
https://bibliotekanauki.pl/articles/358094.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
energetic binder
synthesis
characterization
compatibility
PDN
Opis:
Oxetane-based polymers substituted with difluoroamino groups can be used as energetic binders in propellants and polymer-bonded explosives (PBXs). As a novel candidate, poly(3-difluoroaminomethyl-3-methyloxetane/3-nitratomethyl-3-methyloxetane) (PDN) was synthesized and its structure was established. Thermogravimetry (TG) and differential scanning calorimetry (DSC) were employed to investigate its thermal decomposition behaviour. The compatibility between PDN and some common ingredients of propellants and PBXs was evaluated by the DSC method. PDN with good thermal stability was synthesized via a cationic solution polymerization process. Additionally, it has improved compatibility with cyclotetramethylenetetranitramine (HMX), carbon black (C.B.) and lead carbonate (PbCO3) compared with homopoly(3-difluoroaminomethyl-3-methyloxetane) (PDFAMO). PDN could be used as a promising difluoroamino energetic binder in the future.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 1; 85-99
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predicted Crystal Structures, Analysis, Impact Sensitivities and Morphology of Solid High-Energy Complexes: Alkaline-Earth Carbohydrazide Perchlorates
Autorzy:
Liu, Y.
Zhang, R.
Feng, C.-G.
Yang, L.
Zhang, T.-L.
Powiązania:
https://bibliotekanauki.pl/articles/358890.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
crystal structure
density of state
thermodynamic property
impact sensitivity
crystal morphology
Opis:
The crystal structures, density of states, energy gap, thermodynamic properties, impact sensitivities and morphology of beryllium carbohydrazide perchlorate ([Be(CHZ)3](ClO4)2), magnesium carbohydrazide perchlorate ([Mg(CHZ)3](ClO4)2), calcium carbohydrazide perchlorate ([Ca(CHZ)3] (ClO4)2), strontium carbohydrazide perchlorate ([Sr(CHZ)3](ClO4)2) and barium carbohydrazide perchlorate ([Ba(CHZ)3](ClO4)2) were investigated using the density functional theory (DFT) and crystal morphology theory. The results show that all of the complexes have six-coordinated distorted octahedra, which is different from previous works. This was rationalised by consideration of the intermolecular interactions in the crystal structures. Hence the crystal structure is now more reliable. The chemical reactions of the whole molecule may be triggered by an electron transition of CHZ or ClO4 −. Furthermore the energy gaps were observed, and the values of the impact sensitivities were inferred to have the following sequence: [Be(CHZ)3](ClO4)2 > [Mg(CHZ)3](ClO4)2 > [Sr(CHZ)3](ClO4)2 > [Ca(CHZ)3](ClO4)2 > [Ba(CHZ)3](ClO4)2. In addition, the thermodynamic equations at 25-1000 K were obtained. The positive values of the standard molar free enthalpies shows that carbohydrazide perchlorates are stable at 298.15 K. The (1 0 -1) and (0 0 2) faces are the most important growth directions of the crystal morphologies, and have the minimum growth rates. From the cleaved main growth faces, it can be deduced that surface active agents with active hydrogen atoms in the functional groups could be used as crystal-control reagents to control the crystal morphology for alkaline-earth carbohydrazide perchlorates.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 2; 229-248
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel method to extract vanadium from vanadium-bearing steel slag using sodium carbonate solution
Autorzy:
Gao, M.
Xue, X.
Li, L.
Yang, H.
Bai, R.
Wang, H.
Powiązania:
https://bibliotekanauki.pl/articles/109859.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
leaching
kinetics
vanadium
vanadium-bearing steel slag
Opis:
A new method using sodium carbonate solution to treat a vanadium-bearing steel slag is proposed. The effects of the particle size, solid-to-liquid ratio, initial concentration of sodium carbonate solution, leaching temperature and stirring speed on the leaching rate of vanadium were investigated. The leaching kinetics of vanadium from the vanadium-bearing steel slag was studied, which indicated that the leaching rate was controlled by the step of diffusion through the solid layer around the unreacted core. The apparent activation energy for the process was 13.75 kJ/mol. By using this process, vanadium could be extracted effectively with the leaching rate of more than 80%.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 911-921
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconductor Superlattices with Small Band Offsets - feature article
Autorzy:
Yang, G.
Lewandowski, L. A.
Furdyna, J. K.
Ram-Mohan, L. R.
Powiązania:
https://bibliotekanauki.pl/articles/1968871.pdf
Data publikacji:
1998-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
Opis:
Optical transitions in small band offset superlattices are studied within the framework of the nearly free electron approximation, in which the weak superlattice potential is treated as a perturbation. Interband selection rules are derived for transitions involving conduction and valence band states at the superlattice Brillouin zone center and the zone edge. It is found that a number of new transitions can occur in such small-offset superlattices due to wave function mixing of different subband states. The effect of the effective mass on the optical transitions is also discussed. The theory is used to explain the results observed in magneto-optical absorption experiment in ZnSe/Zn$\text{}_{1-x}$Mn$\text{}_{x}$Se small-offset superlattices. Furthermore, the nearly free electron formulation is found to be in excellent agreement with rigorous multi-band numerical calculation on superlattices involving small band offsets.
Źródło:
Acta Physica Polonica A; 1998, 93, 4; 567-600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Electric Field and Carrier Localization on Carrier Dynamics in AlGaN Quantum Wells
Autorzy:
Mickevičius, J.
Tamulaitis, G.
Kuokštis, E.
Shur, M.
Yang, J.
Gaska, R.
Powiązania:
https://bibliotekanauki.pl/articles/1811960.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.De
Opis:
Dynamics of nonequilibrium carriers in high-Al-content AlGaN/AlGaN multiple quantum wells was studied. A set of multiple quantum wells with well widths varying from 1.65 to 5.0 nm was grown by metal-organic chemical vapor deposition. The structures were investigated by photoluminescence spectroscopy under quasi-steady-state conditions. The observed blueshift of the photoluminescence band peak was attributed to the screening of the built-in electric field. The integrated photoluminescence intensity dependence on excitation and temperature showed a strong influence of carrier localization.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1247-1252
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of CCHP in deep mine thermal hazard control
Zastosowanie systemu trójgeneracji w systemie kontroli zagrożeń termicznych w kopalni głębinowej
Autorzy:
Yang, D. D.
Wang, B. S.
Zhou, S. G.
Qin, R. X.
Powiązania:
https://bibliotekanauki.pl/articles/348684.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
system trójgeneracji
kopalnia o wysokiej metanowości
kontrola zagrożeń cieplnych
chłodzenie absorpcyjne
CCHP
high gas mine
thermal hazard control
absorption refrigeration
Opis:
Due to the characteristics of high gas, high geothermal temperature and high strength development in Huainan mine area, thermal hazard problem has become more and more serious and also affects safety and productivity in coal mine. The CCHP (combined cooling heating and power), as a new mode to control thermal hazard, is put forward after advantages and disadvantages of all kinds of cooling methods are investigated. The CCHP method not only takes full advantage of gas but also reduces the greenhouse gas emission. At the same time, the application of CCHP remits the pressure of the power supply in summer, providing guarantee for safe and high efficiency exploitation.
W związku z wysoką gazonośnością, wysoką temperaturą pierwotną górotworu i wysokimi wartościami zawartości metanu w kopalni Huainan zaobserwowano zagrożenia natury cieplnej, wpływające również na bezpieczeństwo i wydajność produkcji w kopalni. Po zbadaniu wad i zalet różnych metod klimatyzacji podjęto decyzję o wprowadzeniu systemu trójgeneracji jako nowego sposobu kontroli zagrożeń natury cieplnej. Metoda trójgeneracji nie tylko wykorzystuje pełen potencjał ujętego gazu, ale również pozwala obniżyć emisję gazów cieplarnianych. Zastosowanie tego systemu zmniejsza ponadto pobór energii zasilającej w porze letniej, dając gwarancję bezpiecznej i wydajnej eksploatacji kopalni.
Źródło:
AGH Journal of Mining and Geoengineering; 2012, 36, 3; 443-451
1732-6702
Pojawia się w:
AGH Journal of Mining and Geoengineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Udoskonalona metoda dopasowywania krzywych do danych niezawodnościowych uwzględniająca różnice między próbkami
Improved reliability data curve fitting method by considering samples distinction
Autorzy:
Sun, R.
Peng, W. W.
Huang, H. Z.
Ling, D. L.
Yang, J.
Powiązania:
https://bibliotekanauki.pl/articles/301283.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
dopasowywanie krzywych
różnice między próbkami
ważenie danych
proces iteratywny
curve fitting
sample distinction
weigh assignment
iterative process
Opis:
W praktyce inżynieryjnej stykamy się z problemem wykorzystania zgromadzonych danych do oceny maszyn lub sprzętu. Dopasowywanie krzywych to metoda powszechnie używana do rozwiązywania tego typu problemów. W procedurze tej szeroko stosuje się metodę najmniejszych kwadratów. Jeżeli dane wejściowe dopasowywane krzywą można pogrupować tak by tworzyły oddzielne próbki, a różnice między próbkami w sposób oczywisty odzwierciedlają pewną właściwość dotyczącą gromadzenia danych, której nie można pominąć, to konwencjonalna metoda dopasowywania krzywych nie pozwala na analizę takich danych wejściowych. Aby przezwyciężyć to ograniczenie, przedstawiamy udoskonaloną metodę dopasowywania krzywych. Poprzez analizę danych wejściowych, możemy określić związek pomiędzy położeniem próbki a czynnikiem ważonym w dopasowaniu krzywej oraz wykorzystać czynniki ważone przy dopasowywaniu krzywej. Aby osiągnąć jak najdokładniejsze przybliżenie do krzywej rzeczywistej wprowadziliśmy procedurę iteratywną modyfikującą czynniki ważone. Zastosowanie zaproponowanej metody zilustrowano na przykładzie danych z badań niezawodnościowych.
In engineering practice, we face a problem of using some collected data to evaluate a kind of machine or equipment. Curve fitting is a common method to solve this problem. Least square method is wildly applied in this procedure. If the source data of curve fitting can be grouped in samples and the distinction of samples obviously express some character in source data collecting which cannot be ignored. Conventional curve fitting method cannot handle these source data. To deal with this disadvantage, we introduce an improved curve fitting method. Through source data analysis, we can find out the relationship between sample location and weight factor in curve fitting, and use these weight factors for curve fitting. To approach the true curve, we introduce an iterative procedure to modify the weight factors. An engineering example is given to illustrate this proposed method.
Źródło:
Eksploatacja i Niezawodność; 2012, 14, 1; 62-71
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue life prediction for Ni-based superalloy GH4169 considering machined surface roughness and residual stress effects
Autorzy:
Wu, Z. R.
Wang, S. Q.
Yang, X.
Pan, L.
Song, Y. D.
Powiązania:
https://bibliotekanauki.pl/articles/1839712.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
surface roughness
residual stress
fatigue crack
life prediction
GH4169
Opis:
Establishing a fatigue life prediction model considering the machined surface state is of great significance to improve fatigue life prediction accuracy. Fatigue tests with different machined surface states of GH4169 alloy were conducted firstly. The influence of surface state parameters on the fatigue life was analyzed. Then, the machined surface stress concentration factor and residual stress were introduced into the fatigue crack initiation and propagation models. Finally, the fatigue life prediction model of GH4169 material considering the surface states was established. The prediction results based on the proposed model are almost within a factor of two scatter band of the test results.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 2; 215-226
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In vitro cloning potential and phytochemical evaluations of aneuploid individuals produced from reciprocal crosses between diploid and triploid in Echinacea purpurea L.
Autorzy:
Li, Q.
Jiang, W.
Ren, Y.
Chen, R.
Li, X.
Yang, Y.
Wu, H.
Powiązania:
https://bibliotekanauki.pl/articles/58769.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
Aneuploidy often presents large variations in morphology, physiology, biochemistry, and genetics owing to karyotypic imbalance. This study aimed to evaluate the efficacy of aneuploid breeding in Echinacea purpurea L, an important medicinal plant. Reciprocal crosses between diploid and triploid plants were performed to generate aneuploid plants. Cross with triploid as female parent resulted in increased production of aneuploid individuals (19 of 23; 82.61%), while using diploid as female parent yielded much higher percentage of diploid progenies (130 of 133; 97.74%). Each aneuploid had particular karyotypic characteristics compared to the parents. The proportions of median, submedian, and subterminal centromere location chromosomes in gross chromosomes among aneuploids and two parents showed large variations. Although aneuploids had relatively lower adventitious bud regeneration rates than their parents, almost half of them looked morphologically normal, with high survival rates when transplanted to ex vitro conditions. Among the bioactive compounds assessed, cichoric acid and chlorogenic acid contents were extremely encouraging. Most aneuploids had higher cichoric acid and chlorogenic acid contents than their parents. For example, A2 had the highest cichoric acid content of 21.98 mg/g dry weight, more than twice the values of diploid and triploid. Meanwhile, A21 had the highest chlorogenic acid content of 1.84 mg/g, approximately five times more than the parental values. Eleven superior aneuploid lines were successfully screened as breeding candidates. The present findings indicated E. purpurea is highly tolerant of karyotypic imbalance and aneuploid plants could serve as prospective breeding resources in E. purpurea.
Źródło:
Acta Societatis Botanicorum Poloniae; 2017, 86, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressive optical image encryption using phase-shifting interferometry on a joint transform correlator
Autorzy:
Li, J.
Jia, B.
Dai, X.
Lei, M.
Yang, C.
Li, H.
Li, R.
Powiązania:
https://bibliotekanauki.pl/articles/174905.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fully optical system
holographic interferometry
joint transform correlator (JTC)
binary scrambling method
inverse problems
Opis:
A compressive optical image encryption method, which combines compressive sensing with phase-shifting interferometry on a joint transform correlator, is proposed in the fully optical domain. The object image is first permutated using a binary scrambling method. Next, the permutated object field is encrypted and registered as the holograms by phase-shifting interferometry on the joint transform correlator setup. Then, the encrypted images and the key are compressed to the compressed data using single-pixel compressive imaging. The original image can be reconstructed and decrypted using the specified algorithm. The simulations demonstrate that the method is effective and suitable for image security transmission.
Źródło:
Optica Applicata; 2017, 47, 2; 245-256
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eddy current density asymmetric distribution of damper bars in bulb tubular turbine generator
Autorzy:
Qiu, H.
Fan, X.
Yi, R.
Feng, J.
Wu, J.
YANG, C.
ZHAO, H.
Powiązania:
https://bibliotekanauki.pl/articles/140467.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
damper bars
bulb tubular turbine generator
electromagnetic field
eddy current
Opis:
The major reasons that cause the damage of damper bars in the leeward side are found in this paper. It provides a route for the structure optimization design of a hydro generator. Firstly, capacity of a 24 MW bulb tubular turbine generator is taken as an example in this paper. The transient electromagnetic field model is established, and the correctness of the model is verified by the comparison of experimental results and simulation data. Secondly, when the generator is operated at rated condition, the eddy current density distributions of damper bars are studied. And the asymmetric phenomenon of the eddy current density on damper bars is discovered. The change laws of the eddy currents in damper bars are determined through further analysis. Thirdly, through the study of eddy current distributions under different conditions, it is confirmed that the stator slots and armature reaction are the main factors to affect the asymmetric distribution of the eddy current in damper bars. Finally, the studies of the magnetic density distribution and theoretical analysis revealed the asymmetric distribution mechanism of eddy current density.
Źródło:
Archives of Electrical Engineering; 2017, 66, 3; 571-581
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence Studies of Aluminum Nitride Nanowires
Autorzy:
Yang, J.
Na, H.
Kim, H.
Kebede, M.
Choi, R.
Jeong, J.
Lee, C.
Powiązania:
https://bibliotekanauki.pl/articles/1505466.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
We report the production of AlN nanowires by the thermal heating method, for exploring their photoluminescence properties. The room-temperature photoluminescence properties were investigated with different annealing environment. While broad emissions with peaks at around 2.45 and 2.95 eV were obtained from both unannealed and annealed samples, the additional 2.1 eV peak was found from the annealed samples. We have suggested the possible emission mechanisms based on the assumption that both 2.45 eV peak and 2.1 eV peak are ascribed to the nitrogen vacancies. Annealing in N_2 environment exhibited lower intensities of 2.45 eV peak and 2.1 eV peak in comparison to those in Ar environment, presumably due to the suppression of nitrogen vacancies.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 125-127
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Crystal Structure, and Properties of a Novel, Highly Sensitive Energetic, Coordination Compound: Iron (II) Carbohydrazide Perchlorate
Autorzy:
Liu, R.
Zhou, Z.
Qi, S.
Yang, L.
Wu, B.
Huang, H.
Zhang, T.
Powiązania:
https://bibliotekanauki.pl/articles/358343.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
iron (II) carbohydrazide perchlorate
energetic material
high
sensitivity
DFT
energy gap
Opis:
A single crystal of iron (II) carbohydrazide perchlorate [FeII (CHZ)3](ClO4)2 (FeCP), a novel, lead-free, energetic coordination compound, was synthesized and its structure determined by X-ray single crystal diffraction for the frst time. The crystal belongs to the monoclinic system P2(1)/n space group, with a = 1.0066(2) nm, b = 0.8458(2) nm, c = 2.1194(4) nm, β = 100.693(3)° and Z = 4. The central Fe(II) ion is coordinated to three bidentate carbohydrazide units through the carbonyl oxygen atom and an amino nitrogen atom, forming a six-coordinated, non-centrosymmetric complex cation. The thermal analyses by differential scanning calorimetry and thermogravimetry show that the onset temperature of thermal decomposition (152.7 °C) and the critical temperature of thermal explosion of FeCP (161.2 °C) are both much lower than those of other transition metal carbohydrazide perchlorate compounds, and also those of some other primary explosives in service. FeCP has a high enthalpy of combustion, as measured by oxygen bomb calorimetry. The impact, friction and fame sensitivity tests indicate that FeCP is extremely sensitive and hazardous. Unexpected explosions occurred even during the operational processes. In order to explore the intrinsic cause of these explosions, theoretical calculations of the orbital energies were performed based on DTF. These results reveal that the impact sensitivity is positively correlated with the energy gap between HOMO and LUMO: the smaller energy gap results in the higher impact sensitivity.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 1; 17-36
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence Decay Kinetics in GaN Studied by Frequency Domain Measurements
Autorzy:
Mickevičius, J.
Vitta, P.
Tamulaitis, G.
Žukauskas, A.
Shur, M.
Zhang, J.
Yang, J.
Gaska, R.
Powiązania:
https://bibliotekanauki.pl/articles/1813195.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
78.55.Cr
Opis:
Carrier dynamics in high-quality GaN epilayer was investigated at two extreme excitation levels. Carrier lifetime under high excitation conditions was estimated by using light-induced transient grating technique. Measurements at extremely low excitation power density were performed by using frequency-domain fluorescence lifetime technique. The study was performed in a wide temperature range from 8 to 300 K. The results revealed the influence of donor-acceptor pair recombination and carrier trapping processes.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 833-837
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New information on sexual dimorphism and allometric growth in Keichousaurus hui, a pachypleurosaur from the Middle Triassic of Guizhou, South China
Autorzy:
Xue, Y.
Jiang, D.
Motani, R.
Rieppel, O.
Sun, Y.
Sun, Z.
Ji, C.
Yang, P.
Powiązania:
https://bibliotekanauki.pl/articles/19926.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Keichousaurus hui is a small pachypleurosaur (Reptilia: Sauropterygia) from the Triassic of China. Many specimens of various growth stages are known, making them ideal for ontogenetic research. We report 22 new specimens from the Middle Triassic of Xingyi (Guizhou, south China), and combined their skeletal measurements with those from 85 published specimens to analyze the ontogenetic trajectory of sexual dimorphism. An Exploratory Factor Analysis suggests that the largest factors behind morphological disparity within the species are body size followed by gender. Sexual dimorphism is most clearly reflected in selected skeletal ratios that are more pronounced in males than in females. We found that the relative length of femur to body size was useful in gender identification, in addition to three ratios that are traditionally used, namely a distal expansion of the humerus relative to its shaft, humerus length relative to body size, and humerus length relative to femur length. Two distinctive patterns exist in allometric changes of these four ratios. The distal expansion of the humerus is exceptional in that it is equally pronounced in juvenile and adult males and therefore must have been fully established during embryonic growth. The other three features are not pronounced at birth size and subsequently become pronounced during postembryonic growth. However, males and females already show different growth trajectories at birth size even in these three. Therefore, the fate of sexually dimorphic features seems to have already been set during embryonic growth in K. hui.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Impact Toughness of Offshore Steel
Autorzy:
Cheng, T.-C.
Yu, C.
Yang, T.-C.
Huang, C.-Y.
Lin, H.-C.
Shiue, R.-K.
Powiązania:
https://bibliotekanauki.pl/articles/351264.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low-temperature impact toughness
prior austenite grain size
hardenability
bainite
Opis:
This study focused on the effects of microstructures on the low-temperature impact toughness of directly water-quenched offshore steel. Martensite dominated the microstructure directly below the quenched surface. In contrast, mainly lower bainite, martensite, and low amount of ferrite were observed in the central region of the quenched specimen. The ductile to brittle transition temperature of tempered martensite was significantly lower than that of a bainite-dominated microstructure. It is found that low-angle boundaries within the bainite packets greatly impair the low-temperature impact toughness of the steel. The absence of high-angle boundaries in the lower bainite packets significantly deteriorates the low-temperature impact energy of offshore steel.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 167-172
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion-compensating en/decoder for a time-spreading/wavelength-hopping optical code-division multiplexing (OCDM) system
Autorzy:
Zheng, J.
Wang, R.
Pu, T.
Lu, L.
Fang, T.
Su, Y.
Li, L.
Yang, Q.
Chen, X.
Powiązania:
https://bibliotekanauki.pl/articles/174365.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical code-division multiplexing (OCDM)
fiber Bragg grating (FBG)
dispersion
Opis:
A novel dispersion-compensating fiber Bragg grating (FBG)-based en/decoder is proposed to compensate both the out-band and in-band dispersion in a time-spreading/wavelength-hopping (TS/WH) optical code-division multiplexing (OCDM) system. The experimental realization of such en/decoders only needs a uniform-pitch phase mask and a sub-micrometer precision moving stage. Such an en/decoder pair with the ability of compensating the dispersion of transmission in 20-km single mode fiber (SMF) is simulated and experimentally fabricated. Both the simulation and experimental results show that the decoded pulse can be recovered without any distortion owing to the elimination of dispersion.
Źródło:
Optica Applicata; 2013, 43, 3; 485-495
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The endemic radiodonts of the Cambrian Stage 4 Guanshan Biota of South China
Autorzy:
Jiao, D.-G.
Pates, S.
Lerosey-Aubril, R.
Ortega-Hernandez, J.
Yang, J.
Lan, T.
Zhang, X-G.
Powiązania:
https://bibliotekanauki.pl/articles/2082327.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Amplectobeluidae
Anomalocarididae
Tamisiocarididae
Paranomalocaris
Burgess Shale-type exceptional
preservation
shallow water
Cambrian
China
Opis:
The Guanshan Biota (South China, Cambrian, Stage 4) contains a diverse assemblage of biomineralizing and non-biomineralizing animals. Sitting temporally between the Stage 3 Chengjiang and Wuliuan Kaili Biotas, the Guanshan Biota contains numerous fossil organisms that are exclusive to this exceptional deposit. The Guanshan Konservat-Lagerstätte is also unusual amongst Cambrian strata that preserve non-biomineralized material, as it was deposited in a relatively shallow water setting. In this contribution we double the diversity of radiodonts known from the Guanshan Biota from two to four, and describe the second species of Paranomalocaris. In addition, we report the first tamisiocaridid from South China, and confirm the presence of a tetraradial oral cone bearing small and large plates in “Anomalocaris” kunmingensis, the most abundant radiodont from the deposit. All four radiodont species, and three genera, are apparently endemic to the Guanshan Biota. When considered in the wider context of geographically and temporally comparable radiodont faunas, endemism in Guanshan radiodonts is most likely a consequence of the shallower and more proximal environment in which they lived. The strong coupling of free-swimming radiodonts and benthic communities underlines the complex relationship between the palaeobiogeographic and environmental distributions of prey and predators. This local adaptation of radiodonts to their prey is highlighted by the frontal appendage morphology of the two species of Paranomalocaris, apparently specialised to different feeding modes, while the recognition of the limited geographic range of some radiodont faunas highlights the importance of exploring as many deposits as possible to fully understand this group.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 2; 255-274
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pulsed Power and Power Conditioning Capacitors
Autorzy:
Macdougall, F.
Jow, T.
Ennis, J.
Yang, X.
Yen, S.
Cooper, R.
Gilbert, J.
Schneider, M.
Naruo, C.
Bates, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807873.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.32.Tt
84.60.Ve
Opis:
A capacitor development effort focused on capacitors used in pulsed power and power conversion applications underwent at General Atomics Electronic Systems Inc. (GA-ESI) for decades. In recent years, funding for these efforts has accelerated the rate of development progress to the point where the time it takes to decrease the size of a capacitor by half has dropped from 10 years to 4 years. This progress made in pulsed power and power conversion capacitors will be described along with the performance characteristics of today's capacitors.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 989-991
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoexcitation Spectroscopy and Material Alteration with Free-Electron Laser
Autorzy:
Sturmann, J.
Albridge, R. G.
Barnes, A. V.
Gilligan, J.
Graham, M. T.
Mckinley, J. T.
Ueda, A.
Wang, W.
Yang, X.
Tolk, N. H.
Davidson, J. L.
Margaritondo, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963341.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.20.La
79.20.Ds
63.20.-e
79.60.Jv
73.20.At
Opis:
As synchrotron radiation sources have been used for many experiments in the ultraviolet and X-ray regimes, the free-electron laser is an excellent source for a wide array of infrared-photon projects and applications. The free-electron laser delivers a beam of powerful tunable pulsed radiation which provides the opportunity for spatial and temporal localization of the energy delivered at any desired wavelength within the 2-10 μ regime. One application discussed employs the free-electron laser for spectroscopy as a probe of electronic and vibrational structures. Another application uses the free-electron laser beam as a tool for altering materials in a fundamentally new way.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 689-696
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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