Autor: Du, Y. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Effect of minor Cu addition on the precipitation sequence of an as-cast Al-Mg-Si 6005 alloy
Wpływ niewielkiej zawartości miedzi na sekwencje wydzieleń w odlewanych stopach Al-Mg-Si 6005
Autorzy:: Li, K.
Song, M.
Du, Y.
Fang, X.
Powiązania:: https://bibliotekanauki.pl/articles/355082.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: stopy aluminium
dyfrakcja rentgenowska
transmisyjna mikroskopia elektronowa
badania twardości
aluminum alloys
precipitation
ageing
phase transformation
Opis:: The whole precipitation sequences of two as-cast Al-Mg-Si 6005 alloys (containing no Cu or 0.1 wt.% Cu) at 150 degree Celsjus were investigated using X-ray diffraction, transmission electron microscopy and hardness examinations. The precipitation sequence of the Cu-free alloy can be expressed as: super-saturated solid solution (SSSS) → spherical G.P. zones → pre - β'' → β'' → U2 +Si + β _x → Si + β β _xwhile that of the Cu-containing alloy can be expressed as: SSSS → spherical G.P. zones + platelet-like G.P. zones → pre - β → β'' → Q' + β + Si → Q + β + Si. A new type of βprecipitate, namely β _x here, has been discovered in the Cu-free alloy. The addition of minor Cu is found to accelerate the microstructural evolution by inducing the formation of a new type of platelet-like G.P. zone along {111} _Al planes, and improve the hardening response at the over-aged stage by forming Q' and Q precipitates.
Kompletna sekwencja wydzieleń dwóch odlanych stopów Al-Mg-Si 6005 (zawierąjacych 0 i 0.1%.wag Cu), w temperaturze 150 stopni Celsjusza, została zbadana przy użyciu dyfrakcji rentgenowskiej, transmisyjnej mikroskopii elektronowej i badań twardości. Sekwencja wydzieleń w stopie nie zawierającym Cu może być przedstawiona następująco: przesycony roztwór stały → sferyczne strefy Guiniera-Prestona → pre - β'' → β'' → U2 +Si + β _x → Si + β β _x natomiast dla stopu zawierającego Cu następująco: przesycony roztwór stały → sferyczne i płytkowe strefy Guiniera-Prestona → pre - β → β'' → Q' + β + Si → Q + β + Si. Nowy rodzaj wydzieleń β, tj. β x , został odkryty w stopie niezawierajacym Cu. Stwierdzono, że dodatek niewielkiej ilości Cu przyspiesza zmiany mikrostruktury poprzez indukowanie tworzenia nowego typu płytkowych stref Guiniera-Prestona wzdłuż płaszczyzny {111}_Al. i poprawia utwardzenie poprzez tworzenie wydzieleń Q' i Q.
Źródło:: Archives of Metallurgy and Materials; 2012, 57, 2; 458-466
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Y Addition Effects on Hot Deformation Behavior of Cu-Zr Alloys with High Zr Content
Autorzy:: Tian, K.
Tian, B.
Volinsky, A. A.
Zhang, Y.
Liu, Y.
Du, Y.
Powiązania:: https://bibliotekanauki.pl/articles/350979.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: Cu-1%Zr alloy
high Zr content
yttrium
hot deformation activation energy
dynamic recrystallization
Opis:: Isothermal hot compression experiments were carried out using the Gleeble-1500D thermal mechanical simulator. The flow stress of the Cu-1%Zr and Cu-1%Zr-0.15%Y alloys was studied at hot deformation temperature of 550°C, 650°C, 750°C, 850°C, 900°C and the strain rate of 0.001 s^-1, 0.01 s^-1, 0.1 s^-1, 1 s^-1, 10 s^-1. Hot deformation activation energy and constitutive equations for two kinds of alloys with and without yttrium addition were obtained by correlating the flow stress, strain rate and deformation temperature. The reasons for the change of hot deformation activation energy of the two alloys were analyzed. Dynamic recrystallization microstructure evolution for the two kinds of alloys during hot compression deformation was analyzed by optical and transmission electron microscopy. Cu-1%Zr and Cu-1%Zr-0.15%Y alloys exhibit similar behavior of hot compression deformation. Typical dynamic recovery occurs during the 550-750°C deformation temperature, while dynamic recrystallization (DRX) occurs during the 850-900°C deformation temperature. High Zr content and the addition of Y significantly improved Cu-1%Zr alloy hot deformation activation energy. Compared with hot deformation activation energy of pure copper, hot deformation activation energy of the Cu-1%Zr and Cu-1%Zr-0.15%Y alloys is increased by 54% and 81%, respectively. Compared with hot deformation activation energy of the Cu-1%Zr alloy, it increased by 18% with the addition of Y. The addition of yttrium refines grain, advances the dynamic recrystallization critical strain point and improves dynamic recrystallization.
Źródło:: Archives of Metallurgy and Materials; 2018, 63, 2; 875-882
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Morphology and developmental traits of the trilobite Changaspis elongata from the Cambrian Series 2 of Guizhou, South China
Autorzy:: Du, G.-Y.
Peng, J.
Wang, D.-Z.
Wang, Q.-J.
Wang, Y.-F.
Zhang, H.
Powiązania:: https://bibliotekanauki.pl/articles/22906.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:: The morphology and ontogeny of the trilobite Changaspis elongata based on 216 specimens collected from the Lazizhai section of the Balang Formation (Stage 4, Series 2 of the Cambrian) in Guizhou Province, South China are described. The relatively continuous ontogenetic series reveals morphological changes, and shows that the species has seventeen thoracic segments in the holaspid period, instead of the sixteen as previously suggested. The development of the pygidial segments shows that their number gradually decreases during ontogeny. A new dataset of well-preserved specimens offers a unique opportunity to investigate developmental traits after segment addition is completed. The ontogenetic size progressions for the lengths of cephalon and trunk show overall compliance with Dyar’s rule. As a result of different average growth rates for the lengths of cephalon, trunk and pygidium, the length of the thorax relative to the body shows a gradually increasing trend; however, the cephalon and pygidium follow the opposite trend. Morphometric analysis across fourteen post-embryonic stages reveals growth gradients with increasing values for each thoracic segment from anterior to posterior. The reconstruction of the development traits shows visualization of the changes in relative growth and segmentation for the different body parts. The new dataset and growth gradient of the trunk suggest that the thoracic segment growth dynamics of early Cambrian to Silurian trilobites follow the same general continuous, steady-state growth gradient decreasing from posterior to anterior.
Źródło:: Acta Palaeontologica Polonica; 2019, 64, 4
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Simulation and experimental study of SCR injection system
Autorzy:: Du, J.
Zhang, Y.
Cai, Y.
Powiązania:: https://bibliotekanauki.pl/articles/260223.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: ammonia grille
flow field
uniformity
SCR test
the denitrification rate
Opis:: According to actual engineering test, we design a linear controlled spray ammonia grille, and apply it to the SCR injection system of ship tail gas treatment. In this paper, the geometric model of ammonia injection grid was built in the flue of diesel engine, and the effects of spray atomization, ammonia uniformity and urea droplet distribution on spray atomization were simulated. Then the test bench was set up to observe the injection status of the ammonia injection grille. The NOx content of the outlet was measured by the original data of the flue gas, and the experimental data were processed. We calculate the denitrification rate by taking the average value to verify the correctness of the spray ammonia grid scheme.
Źródło:: Polish Maritime Research; 2018, S 2; 49-55
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: A Deep Q-Learning Network for ship stowage planning problem
Autorzy:: Shen, Y.
Zhao, N.
Xia, M.
Du, X.
Powiązania:: https://bibliotekanauki.pl/articles/260614.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: Deep Q-Leaning Network (DQN)
container terminal
ship stowage plan
markov decision process
value function approximation
generalization
Opis:: Ship stowage plan is the management connection of quae crane scheduling and yard crane scheduling. The quality of ship stowage plan affects the productivity greatly. Previous studies mainly focuses on solving stowage planning problem with online searching algorithm, efficiency of which is significantly affected by case size. In this study, a Deep Q-Learning Network (DQN) is proposed to solve ship stowage planning problem. With DQN, massive calculation and training is done in pre-training stage, while in application stage stowage plan can be made in seconds. To formulate network input, decision factors are analyzed to compose feature vector of stowage plan. States subject to constraints, available action and reward function of Q-value are designed. With these information and design, an 8-layer DQN is formulated with an evaluation function of mean square error is composed to learn stowage planning. At the end of this study, several production cases are solved with proposed DQN to validate the effectiveness and generalization ability. Result shows a good availability of DQN to solve ship stowage planning problem.
Źródło:: Polish Maritime Research; 2017, S 3; 102-109
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Synchronization and stability of an elastically coupled tri-rotor vibration system
Autorzy:: Hou, Y.
Du, M.
Fang, P.
Zhang, L.
Powiązania:: https://bibliotekanauki.pl/articles/279489.pdf
Data publikacji:: 2017
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: tri-rotor
synchronization characteristics
stability
computer simulations
Opis:: A new mechanism, an elastically coupled tri-rotor system, is proposed to implement synchronization. It is composed of a rigid body, three induction motors, coupling unit and springs. According to the Lagrange equation, the model of the system is established. The average method of small parameters is applied to study the synchronization characteristics of the system, therefore, the balance equation and stability criterion of the system can be obtained. Obviously, many parameters affect the synchronous state of the rotors, especially the spring stiffness, the stiffness of the coupling unit and the installation location of the system. Finally, computer simulations are used to verify the correctness of theoretical analysis.
Źródło:: Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 227-240
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Comparative investigations of nonlinear and linear observers for a highly manoeuvrable target in sliding mode guidance
Autorzy:: Wang, Y.
Sun, M.
Du, S.
Chen, Z.
Powiązania:: https://bibliotekanauki.pl/articles/201020.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: guidance law
second-order sliding mode
super-twisting algorithm
linear observer
target manoeuvre
algorytm
obserwator liniowy
manewr
algorytm przesuwania
Opis:: Target manoeuvre is one of the key factors affecting guidance accuracy. To intercept highly maneuverable targets, a second-order sliding-mode guidance law, which is based on the super-twisting algorithm, is designed without depending on any information about the target motion. In the designed guidance system, the target estimator plays an essential role. Besides the existing higher-order sliding-mode observer (HOSMO), a first-order linear observer (FOLO) is also proposed to estimate the target manoeuvre, and this is the major contribution of this paper. The closed-loop guidance system can be guaranteed to be uniformly ultimately bounded (UUB) in the presence of the FOLO. The comparative simulations are carried out to investigate the overall performance resulting from these two categories of observers. The results show that the guidance law with the proposed linear observer can achieve better comprehensive criteria for the amplitude of normalised acceleration and elevator deflection requirements. The reasons for the different levels of performance of these two observer-based methods are thoroughly investigated.
Źródło:: Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 2; 233-245
0239-7528
Pojawia się w:: Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Molecular phylogeny of Populus (Salicaceae, Salicales) with focus on inter- and intrasectional relationships
Autorzy:: Du, S.
Hu, X.
Yang, Y.
Wang, Z.
Powiązania:: https://bibliotekanauki.pl/articles/2130215.pdf
Data publikacji:: 2022
Wydawca:: Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:: molecular phylogeny
section Populus
section Tacamahaca
section Aigeiros
Opis:: The relationships among sections and species within each section in the genus Populus have attracted much attention from taxonomists and biologists. In this paper, we provide an overview of the current state of Populus phylogenetics and discuss the origin of some hybrid species. There has been some controversy surrounding the origin of the genus Populus in North America and subsequent dispersal and differentiation in other parts of the world. We present the most plausible scenario based on phylogenetic analysis and fossil records. Sections Abaso, Turanga and Populus are all monophyletic, whereas sections Aigeiros, Tacamahaca and Leucoidesshow some degree of polyphyly. Sections Abaso and Turanga are relatively primitive lineages in Populus. With the accumulation of sequencing data and new analytical tools, it will be possible to investigate more complicated issues concerning genus Populus within a phylogenetic framework.
Źródło:: Dendrobiology; 2022, 88; 56-69
1641-1307
Pojawia się w:: Dendrobiology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Adsorption of congo red from aqueous solutions by porous soybean curd xerogels
Autorzy:: Zhang, Z.
Li, Y.
Du, Q.
Li, Q.
Powiązania:: https://bibliotekanauki.pl/articles/778311.pdf
Data publikacji:: 2018
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:: Soybean curd
Congo red
Adsorption
Kinetics
Thermodynamics
Opis:: Soybean curd is a very popular food containing high-quality protein, polyunsaturated fats, vitamins, minerals and other nutrients. This study aims to prepare porous soybean curd xerogels via a vacuum freeze drying method and uses them as adsorbents to remove congo red from aqueous solutions. The morphology and functional groups of the soybean curd xerogels were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The adsorption properties of congo red onto the soybean curd xerogels were carried out through investigating the influencing experimental parameters such as the drying method, solution pH, adsorbent dose, contact time and temperature. The results showed that the adsorption isotherm data were fitted well to the Freundlich isotherm. Adsorption kinetics of congo red onto the soybean curd followed the pseudo-second-order kinetic model. The thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were also determined.
Źródło:: Polish Journal of Chemical Technology; 2018, 20, 3; 95-102
1509-8117
1899-4741
Pojawia się w:: Polish Journal of Chemical Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Modification Mechanism and Growth Process of Al₃(Sc, Zr) Particles in As-cast Al-Si-Mg-Cu-Zr-Sc Alloy
Autorzy:: Li, Y.
Du, X.
Fu, J.
Zhang, Y.
Zhang, Z.
Zhou, S.
Wu, Y.
Powiązania:: https://bibliotekanauki.pl/articles/382672.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: solidification process
Al3(Sc, Zr)
three-dimensional morphology
eutectic growth
krzepnięcie stopu
morfologia trójwymiarowa
wzrost eutektyczny
Opis:: In this study, the modification mechanism and growth process of Al₃(Sc, Zr) particles in as-cast Al-Si-Mg-Cu based alloy with addition of Sc and Zr were systematically investigated. It was found that 0.57 wt-%Sc addition caused a significant refinement in the average grain size of the investigated alloy, which brought about a remarkable transformation in as-cast microstructure, from thick dendritic shape to fine equiaxed structure. A large amount of primary Al₃(Sc, Zr) particles with the dimension of around 5-6 μm were also observed within the equiaxed grain. Due to the identical orientation and similar crystal structure between primary Al₃(Sc, Zr) particles and α-Al matrix, the primary particles always served as heterogeneous nucleus for the α-Al matrix. In addition, these cusped cubic primary Al₃(Sc, Zr) particles showed triangle, star, rhomboid morphologies are generated from sectioning the particle in (111), (100) and (110) planes, respectively. Particularly, the typical eutectic structure which contained odd number-layer (Al₃(Sc, Zr)+α-Al+ ... +Al₃(Sc, Zr)) was observed within the investigated particles.
Źródło:: Archives of Foundry Engineering; 2018, 18, 2; 51-56
1897-3310
2299-2944
Pojawia się w:: Archives of Foundry Engineering
Dostawca treści:: Biblioteka Nauki

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