Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Xu, M." wg kryterium: Autor


Tytuł:
Zastosowania nadprzewodników wysokotemperaturowych do ograniczania prądu
Applications of HTc superconductors for current limitation
Autorzy:
Sosnowski, J.
Horyń, R.
Bukowska, E.
Koblischka, M.R.
Xu, Y.
Boreta, B.
Powiązania:
https://bibliotekanauki.pl/articles/159126.pdf
Data publikacji:
2006
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
nadprzewodnictwo wysokotemperaturowe
ograniczniki prądu
ekran nadprzewodnikowy
Opis:
W pracy przedyskutowano zastosowania nadprzewodników wysokotemperaturowych w ogranicznikach prądowych. Przedstawiono konstrukcję modelu rezystywnego, nadprzewodnikowego ogranicznika prądu zwarcia, przeznaczonego do ograniczania prądu o natężeniu rzędu kilkudziesięciu amperów oraz przygotowania do konstrukcji indukcyjnego ogranicznika. Przedstawiono model matematyczny działania ogranicznika. W rezystywnej konstrukcji wykorzystano taśmy nadprzewodnikowe z nadprzewodnika typu Bi:2223 pracujące w otoczeniu ciekłego azotu, podczas gdy przewiduje się wykonać prototyp indukcyjnego ogranicznika w oparciu o ekrany nadprzewodnikowe również z nadprzewodnika opartego na bizmucie. Przedstawiono rezultaty prac technologicznych nad uzyskaniem tych ekranów i analizę dyfraktograficzną otrzymanych proszków bizmutowych typu Bi:2212, spieczonych z polskich surowców. Jakkolwiek uzyskano jednorodny rentgenograficznie materiał typu Bi:2212, to jednak przejście nadprzewodzące zmierzone metodami magnetycznymi było dość rozmyte. Wymaga to kontynuacji prac nad uzyskaniem materiałów o odpowiednich parametrach nadprzewodnikowych.
Applications of HTc superconductors in the fault current limiters has been discussed. A model of the constructed resistive type superconducting fault current limiter has been presented, which is devoted to current limitation at the level of several dozen of amperes, as well as the preparation for construction of the inductive type superconducting current limiter. The mathematical model of limiters has been discussed. In the resistive model the HTc superconducting Bi:2223 tapes have been used, working in liquid nitrogen environment. It is expected too built a model of inductive fault current limiter in which the active element would be the superconducting shields. Results of the technological work on the design of these superconducting shields, using the commercially available powders are presented. The diffractographic analysis of prepared materials was presented too. Although a homogeneous (from the crystallographic point of view) material of the type Bi:2212 was obtained, the superconducting transition curves were relatively wide. Continuation of the work on the superconducting materials technology process is recessary.
Źródło:
Prace Instytutu Elektrotechniki; 2006, 226; 125-147
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The forwarding indices of graphs - a survey
Autorzy:
Xu, J.-M.
Xu, M.
Powiązania:
https://bibliotekanauki.pl/articles/255669.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
graph theory
vertex-forwarding index
edge-forwarding index
routing
networks
Opis:
A routing R of a connected graph G of order n is a collection of n(n — 1) simple paths connecting every ordered pair of vertices of G. The vertex-forwarding index £(G,R) of G with respect to a routing R is defined as the maximum number of paths in R passing through any vertex of G. The vertex-forwarding index £(G) of G is defined as the minimum £(G,R) over all routings R of G. Similarly, the edge-forwarding index π (G,R) of G with respect to a routing R is the maximum number of paths in R passing through any edge of G. The edge-forwarding index π (G) of G is the minimum π(G, R) over all routings R of G. The vertex-forwarding index or the edge-forwarding index corresponds to the maximum load of the graph. Therefore, it is important to find routings minimizing these indices and thus has received much research attention for over twenty years. This paper surveys some known results on these forwarding indices, further research problems and several conjectures, also states some difficulty and relations to other topics in graph theory.
Źródło:
Opuscula Mathematica; 2013, 33, 2; 345-372
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of injection pressure and strategy in a Jaguar V6 diesel engine
Autorzy:
Abdullah, N. R.
Mamat, R.
Rounce, P.
Wyszynski, M. L.
Tsolakis, A.
Xu, H. M.
Tian, G.
Powiązania:
https://bibliotekanauki.pl/articles/242414.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
combustion
emissions
injection strategies
premixed combustion
ignition delay
Opis:
In recent years, the improvement of engine performance and emissions has become an extremely important concern. This study focuses on the injection strategy based on the injection pressure (IP) and duration between pilot injection and the main injection (dMI) using a multi cylinder common rail multiple injections diesel engine. The study was designed to produce improvements in fuel mixing via the injection strategy, to reduce the main ignition delay. This would contribute to a minimum amount of fuel burnt in the premixed combustion phase, leading to a reduction in emissions. Recent evidence shows that premixed combustion is significant in the controlling of emissions of nitrogen oxides (NOx) and soot. Six different IPs combined with a short and long dMI were compared in the attempt to improve engine performance and emissions. The engine performance was measured in terms of brake specific fuel consumption, ignition delay, heat release and peak in-cylinder pressure and emissions, specifically nitrogen oxides (NOx), total unburned hydrocarbons (THC), carbon monoxide (CO) and smoke emissions for each engine test condition. The evidence from this study shows that the effect of IP is more dominant than dMI in terms of peak cylinder pressure, heat release, brake specific fuel consumption and emissions. However, the dMI shows a strong effect at a higher engine speed.
Źródło:
Journal of KONES; 2009, 16, 2; 9-22
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System for Calibrating Analogue Merging Units in Absence of Synchronization Signals
Autorzy:
Cheng, H.-M.
Huang, Q.-F.
Ji, F.
Xu, Q.
Liu, J.
Tian, Z.
Powiązania:
https://bibliotekanauki.pl/articles/221084.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
intelligent substation
analogue merging unit
peer-to-peer communication
calibration system
synchronization signal
Opis:
Synchronization signals are requisite for calibrating electrical measurement devices with digital output when using conventional calibration methods. However, since the signal sampling process of the analogue merging units (MUs) operating in an intelligent substation does not rely on external synchronization signals, accuracy calibration without the use of synchronization signals is of particular importance in order to guarantee the measurement accuracy in practical situations. So far, very little research on calibration systems independent of synchronization signals has been performed. This paper presents a design of the calibration system without dependence on synchronization signals. To verify the feasibility of the proposed design, the designed system and a conventional calibration system have been employed in testing the accuracy of the same analogue MU of a 0.2 accuracy class. The comparison of the test results shows that the differences of ratio errors are below 0.02%, and the maximum difference of phase errors is about 4′. This paper also provides a new efficient and significant calibration method which does not require any external synchronization signals.
Źródło:
Metrology and Measurement Systems; 2018, 25, 1; 129-138
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of PolyNIMMO-HTPB-polyNIMMO Triblock Copolymer as a Potential Energetic Binder
Autorzy:
Wang, X.
Shu, Y.
Lu, X.
Mo, H.
Xu, M.
Powiązania:
https://bibliotekanauki.pl/articles/358529.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
triblock copolymer
cationic ring opening polymerization
polymer
DSC
Opis:
Triblock copolymer polyNIMMO-HTPB-polyNIMMO was synthesized by cationic ring opening polymerization of NIMMO (3-nitratomethyl-3-methyloxetane) in the presence of hydroxyl-terminated polybutadiene catalyzed by BF3·OEt2. The polymer was characterized by FT-IR, 1H NMR, 13C NMR spectroscopy, and GPC. DSC was used to investigate the thermal behaviour of the triblock copolymer and its exothermic decomposition peak was found to be at 215 °C. All of the results indicated that the triblock copolymer polyNIMMO-HTPB-polyNIMMO might serve as a potential energetic propellant binder.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 3; 456-467
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability control of propeller Autonomous Underwater Vehicle based on combined sections method
Autorzy:
Qi, D.
Feng, J.
Liu, A.
Hu, J.
Xu, H.
Li, Y.
Ashraf, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/259119.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
propeller AUV
dynamic model
stability control
simulation
Opis:
Learning from the motion principle of quadrotor, a symmetric propeller AUV, which has small size and low velocity is designed. Compared with the AUV equipped with rudders, it has better maneuverability and manipulation at low velocity. According to the Newton-Euler method, the 6 DOF kinematic model and dynamic model of the propeller AUV are established. A stability controller that consists of 3 different PID controllers is designed. It makes the depth and attitude angle as trigger conditions, and the relevant controller is chosen in different moving process. The simulation experiments simulate ideal motion state and disturbed motion state, and experiments results show that the stability controller based on combined sections method can make the best of mature technology of PID, and meet the control requirements in different stages. It has a higher respond speed and accuracy, improving the stability of the propeller AUV under the disturbance of complex ocean currents.
Źródło:
Polish Maritime Research; 2015, S 1; 157-162
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability and Hopf bifurcation analysis for a Lotka-Volterra predator-prey model with two delays
Autorzy:
Xu, C.
Liao, M.
He, X.
Powiązania:
https://bibliotekanauki.pl/articles/907822.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
opóźnienie
stabilność
bifurkacja Hopfa
predator-prey model
delay
stability
Hopf bifurcation
Opis:
In this paper, a two-species Lotka-Volterra predator-prey model with two delays is considered. By analyzing the associated characteristic transcendental equation, the linear stability of the positive equilibrium is investigated and Hopf bifurcation is demonstrated. Some explicit formulae for determining the stability and direction of Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by using normal form theory and center manifold theory. Some numerical simulations for supporting the theoretical results are also included.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2011, 21, 1; 97-107
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft Sensing Method Of LS-SVM Using Temperature Time Series For Gas Flow Measurements
Autorzy:
Xu, W.
Fan, Z.
Cai, M.
Shi, Y.
Tong, X.
Sun, J.
Powiązania:
https://bibliotekanauki.pl/articles/221824.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas flow
soft sensor
support vector machine (SVM)
temperature time series
Opis:
This paper proposes a soft sensing method of least squares support vector machine (LS-SVM) using temperature time series for gas flow measurements. A heater unit has been installed on the external wall of a pipeline to generate heat pulses. Dynamic temperature signals have been collected upstream of the heater unit. The temperature time series are the main secondary variables of soft sensing technique for estimating the flow rate. A LS-SVM model is proposed to construct a non-linear relation between the flow rate and temperature time series. To select its inputs, parameters of the measurement system are divided into three categories: blind, invalid and secondary variables. Then the kernel function parameters are optimized to improve estimation accuracy. The experiments have been conducted both in the single-pulse and multiple-pulse heating modes. The results show that estimations are acceptable.
Źródło:
Metrology and Measurement Systems; 2015, 22, 3; 383-392
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation model and state analysis of ship transmission line
Autorzy:
Hu, Y.
Xu, M.
Li, Y.
Powiązania:
https://bibliotekanauki.pl/articles/259613.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship power
transmission line
simulation model
insulation deterioration
Opis:
In order to discuss the simulation model of the ship transmission line and the state of the transmission line, an early fault model is built according to the evolution principle of the short circuit fault of the transmission line and combining with the fault characteristics of the early fault. A small distributed ship transmission line system is built in MATLAB/ Simulink. Then, combined with the constructed fault module, the original short circuit module, and the load module, the various states (normal state, early fault state, severe early fault state, short circuit state) of the ship transmission line are stimulated, and the features of voltage signal in each state is analysed. It is concluded that, due to the normal operation of the ship transmission line system, the variation characteristics of the flow signal and voltage signal caused by the sudden load mutation, that is, the sudden load and the sudden increase load, are very similar to the changes caused by the early fault. Therefore, in order to find a more accurate early fault detection method, the state is divided into normal state, sudden load state, sudden increase and sudden decrease load state.
Źródło:
Polish Maritime Research; 2018, S 3; 36-42
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seasonal dynamics in cambial activity and the formation of xylem and phloem in the branches of Cinnamomum camphora
Autorzy:
Dong, M.
Xu, Y.M.
Lin, H.
Li, X.Q.
Xia, Q.Q.
Powiązania:
https://bibliotekanauki.pl/articles/41385.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
seasonal dynamics
cambial activity
formation
xylem
phloem
branch formation
tree
tropical tree
Cinnamomum camphora
wood formation
phenology
Opis:
The cambial activity and periodicity of secondary xylem and phloem formation have been less studied in tropical tree species than in temperate ones. Cambium activity is the only source of timber production. Studies on its activity and xylem formation can provide helpful data for dendrochronology and possible factors that control tree growth, the yield and quality of wood. Cinnamomum camphora is an important fast-growing tree for furniture and sculpture wood in South China. Its dynamics of cambial activity was not reported. During the growth season in 2011, five trees of Cinnamomum camphora plantation were monitored on the campus of Huazhong Agricultural University in central china (located on 113°41’ to 115°05’ E and 29°58’ to 31°22’ N). Sampling time was from 13, February 2011 to 13, February 2012. Some small stems of 15–20 cm length were selected to sample in the middle of 2–3 years old health branches in the central crown of these trees. The observational study found that the cambium of camphor trees was active from March to October and dormant from November to February. Onset of cambial cell division was observed in early March, one week after sprouting of new buds. The morphology of the cells and number of cell layers in the cambium zone varied throughout the year. In early March, cambium reactivated with the rising of temperature, the cell wall was relative thick. The number of cell layers increased from 2–3 in middle Feb. to 3–5. In June, the number of cell layers in cambium reached the maximum of 5–7 in a radial direction. In mid March, phloem cells began to differentiate, followed by xylem three weeks later. The number of cell layers in immature phloem and xylem increased dramatically before mid June and the increment of cell layers in xylem was almost fifth times of phloem in the differentiating process. The phloem cells mainly stopped dividing new cells in end of October, but xylem cells were still in the activity a week later. The annual activities of cambium was in accordance with the air mean temperature change in 2011–2012. The results showed that the cambial activity and formation of xylem and phloem were related to the environmental factors, especially the temperature.
Źródło:
Dendrobiology; 2016, 75
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of the Photodecomposition of Some Important Energetic Materials
Autorzy:
Sun, Y.
Shu, Y.
Xu, T.
Shui, M.
Zhao, Z.
Gu, Y.
Wang, X.
Powiązania:
https://bibliotekanauki.pl/articles/358397.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
photodecomposition mechanisms
energetic materials
Opis:
The photodecomposition mechanisms of energetic materials vary with molecular structure, photodissociation wavelength, the phase of the material, experimental pressure and temperature etc. In this paper, the significant progress on photodecomposition studies of some important energetic materials achieved in recent years is introduced in detail, including nitromethane, DMNA (dimethylnitramine), TATB (1,3,5-triamino-2,4,6-trinitrobenzene), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), HMX (1,3,5,7-tetranitro-1,3,5,7- tetrazacycloctane) and CL-20 (2,4,6,8,10,12-hexanitrohexaazaisowurtzitane). The difficulties and prospects of photodecomposition research of energetic materials are also indicated.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 4; 411-423
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review and future perspectives on the integration characteristics for equine lentivirus in the host genome
Autorzy:
Yu, Y.-Y.
Xu, M.-S.
Liang, H.
Wang, H.-Y.
Yu, C.-Q.
Liu, Q.
Powiązania:
https://bibliotekanauki.pl/articles/16647532.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
lentivirus
equine infectious anemia virus
integration
long interspersed elements
Opis:
Despite over 40 years of research on the human immunodeficiency virus type 1 (HIV-1) vaccine, we still lack a considerable progress. Equine infectious anemia virus (EIAV) is a lentivirus in the Retroviridae family, akin to HIV-1 in genome structure and antigenicity. EIA is an important infectious disease in equids, characterized by anemia, persistent infection, and repeated fevers. The EIAV attenuated vaccine in China is the only lentiviral vaccine used on a large scale. Elucidating the mechanism of waning and induction of protective immunity from this attenuated vaccine strain will provide a critical theoretical basis and reference point for vaccine research, particularly in the development of lentivirus vaccines, with far-reaching scientific value and social significance. In this paper, we summarize the information related to EIAV integration site selection, particularly for the Chinese EIAV attenuated vaccine strains on the equine genome. This may improve our mechanistic understanding of EIAV virulence reduction at the host genome level. The obtained data may help elucidate the biological characteristics of EIAV, particularly the Chinese attenuated EIAV vaccine strain, and provide valuable information regarding retroviral infections, particularly lentiviral infection and associated therapeutic vectors.
Źródło:
Polish Journal of Veterinary Sciences; 2023, 26, 1; 163-172
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Report on the archaeological survey at Gebelein in the 2014, 2015 and 2016 seasons
Autorzy:
Ejsmond, Wojciech
Chyla, Julia M.
Witkowski, Piotr
Takács, Dániel
Wieczorek, Dawid F.
Xu-Nan, Lawrence
Oeters, Vincent
Kuronuma, Taichi
Grylak, Adam
Powiązania:
https://bibliotekanauki.pl/articles/1684198.pdf
Data publikacji:
2018-07-09
Wydawca:
Uniwersytet Warszawski. Wydawnictwa Uniwersytetu Warszawskiego
Tematy:
Gebelein
mobile GIS
geophysical prospection
archaeological survey
epigraphic survey
satellite imagery
RTI
decorrelation
Opis:
All periods of Egyptian history are represented at Gebelein and it encompasses many kinds of archaeological site found in the Nile valley (that is, cemeteries, settlements, fortifications, temples, rock quarries etc.). The area was a significant centre in the history of ancient Egypt, but its exact role and the reasons for its importance still awaits explanation. That is why the Gebelein Archaeological Project was initiated. The field survey of Gebelein, which started in 2014, aims to recognise the topography of the area and the degree of destruction of the sites and to locate archaeological remains as well as to determine their interpretation and dating. This report outlines the results of work conducted during seasons 2014, 2015 and 2016, which encompassed the archaeological and epigraphic field surveys, geophysical prospection as well as work conducted in the rock-cut chapel of Hathor.
Źródło:
Polish Archaeology in the Mediterranean; 2017, 26(1); 239-268
1234-5415
Pojawia się w:
Polish Archaeology in the Mediterranean
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:
Osteology of the Late Cretaceous alvarezsauroid Linhenykus monodactylus from China and comments on alvarezsauroid biogeography
Autorzy:
Xu, X.
Upchurch, P.
Ma, Q.
Pittman, M.
Choiniere, J.
Sullivan, C.
Hone, D.W.E.
Tan, Q.
Tan, L.
Xiao, D.
Han, F.
Powiązania:
https://bibliotekanauki.pl/articles/20629.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
osteology
Cretaceous
Late Cretaceous
alvarezsauroid
Linhenykus monodactylus
China
biogeography
Dinosauria
Theropoda
Parvicursorinae
Treefitte
dispersal
vicariance
sympatry
Wulansuhai Formation
Inner Mongolia
Opis:
The alvarezsauroid theropod Linhenykus monodactylus from the Upper Cretaceous of Inner Mongolia, China is the first knownmonodactyl non−avian dinosaur, providing important information on the complex patterns of manual evolution seen in alvarezsauroids. Herewe provide a detailed description of the osteology of this taxon. Linhenykus shows a number of fea− tures that are transitional between parvicursorine and non−parvicursorine alvarezsauroids, but detailed comparisons also re− veal that some characters had a more complex distribution. We also use event−based tree−fitting to perform a quantitative analysis of alvarezsauroid biogeography incorporating several recently discovered taxa. The results suggest that there is no statistical support for previous biogeographic hypotheses that favour pure vicariance or pure dispersal scenarios as explana− tions for the distributions of alvarezsauroids across SouthAmerica, NorthAmerica andAsia. Instead, statistically significant biogeographic reconstructions suggest a dominant role for sympatric (or “within area”) events, combined with a mix of vicariance, dispersal and regional extinction. At present the alvarezsauroid data set is too small to completely resolve the biogeographic history of this group: future studies will need to create larger data sets that encompass additional clades.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies