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Wyszukujesz frazę "Xiao, Feng" wg kryterium: Autor


Tytuł:
Proficiency effect on L2 pragmatic competence
Autorzy:
Xiao, Feng
Tematy:
proficiency effect
L2 pragmatic competence
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Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Powiązania:
https://bibliotekanauki.pl/articles/780487.pdf  Link otwiera się w nowym oknie
Opis:
This paper synthesizes cross-sectional studies of the effect of proficiency on second language (L2) pragmatics to answer the synthesis question: Does proficiency affect adult learners’ pragmatic competence? Findings have revealed an overall positive proficiency effect on pragmatic competence, and in most cases higher proficiency learners have higher pragmatic competence. However, increased proficiency does not guarantee a native-like pragmatic performance because proficiency effect varies depending on the nature of target pragmatic features such as types of speech acts (degrees of directness and conventionality) (e.g., Cook & Liddicoat, 2002; Félix-Brasdefer, 2007), modalities of pragmatic performance (comprehension and production) (e.g., Bradovi-Harlig, 2008, 2009), social variables involved in task situations, such as social status (e.g., Allami & Naeimi, 2011), social distance (e.g., Maeshiba, Yoshinaga, Kasper, & Ross, 1996), and power relationship (e.g., Al-Gahtani & Roever, 2012). Moreover, proficiency effect is mediated by contextual variables such as length of stay in the target language community (e.g., Shardakova, 2005; Taguchi, 2011, 2013; Xu, Case, & Wang, 2009).
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on flotation behavior and mechanism of separating chalcopyrite and Molybdenite with ethyl mercaptoglycolate as inhibitor
Autorzy:
Yang, Xiao-Feng
Xu-Zhao
Liu, Yao-Yao
Tematy:
ethyl thioglycolate
chalcopyrite
molybdenite
inhibitor
separation
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/24085868.pdf  Link otwiera się w nowym oknie
Opis:
The effect of ethyl thioglycolate organic small molecule inhibitors on chalcopyrite molybdenite flotation behaviour is investigated via single mineral micro-flotation tests, zeta potential tests, and X-ray photoelectron spectroscopy (XPS) analysis. Results of the flotation test indicate that ethyl thioglycolate organic small-molecule inhibitors can effectively separate Cu and Mo and selectively inhibit chalcopyrite under weak alkaline conditions. Infrared spectroscopy and XPS analysis show that hydrophilic functional groups C=O and -COOH in the ethyl thioglycolate organic small molecules can chemically adsorb onto the chalcopyrite surface. Moreover, ethyl thioglycolate has no obvious effect on zeta potential of molybdenite. Therefore, ethyl thioglycolate can effectively separate chalcopyrite and molybdenite.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Insensitive RDX by Suspension Spray Technology and Its Characterization
Autorzy:
Yan, Xiang
Li, Xiao Dong
Zhou, Peng
Ji, Wei
Shi, Xiao Feng
Tematy:
RDX
Estane 5703
suspension spray technology
detonation velocity
insensitivity
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Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:
https://bibliotekanauki.pl/articles/358585.pdf  Link otwiera się w nowym oknie
Opis:
A new insensitive and high energy explosive based on RDX was prepared by suspension spray technology using Estane 5703 as a binder (e-RDX). Scanning electron microscopy was used to characterize the morphology and particle size of the samples. The composite was analyzed by differential scanning calorimetry and X-ray photoelectron spectroscopy. Its impact sensitivity and detonation velocity were determined. For comparison, raw RDX, refined RDX (r-RDX) and solution spray dried RDX/Estane 5703 (e1-RDX) were also tested using these five methods. The SEM results showed that the e-RDX size was 1-3 μm. e1-RDX exhibited a spherical shape with some defects on the surface. The XPS results indicated that Estane 5703 can be successfully coated onto the surface of e-RDX. Compared to raw RDX, the drop height of r-RDX, e1-RDX and e-RDX was increased, being 16.5 cm, 32.9 cm and 58.4 cm, respectively. The activation energy of e-RDX is lower than that of raw RDX, but a little higher than that of e1-RDX. Compared to raw RDX, the detonation velocity of r-RDX, e1-RDX, w-RDX and e-RDX had decreased, being 110 m·s–1, 710 m·s–1, 410 m·s–1 and 210 m·s–1, respectively.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new low SNR underwater acoustic signal classification method based on intrinsic modal features maintaining dimensionality reduction
Autorzy:
Ju, Yang
Wei, Zhengxian
Li, Huangfu
Feng, Xiao
Tematy:
acoustic
low SNR
signal classification
feature maintain
dimension reduction
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Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/259300.pdf  Link otwiera się w nowym oknie
Opis:
The classification of low signal-to-noise ratio (SNR) underwater acoustic signals in complex acoustic environments and increasingly small target radiation noise is a hot research topic. . This paper proposes a new method for signal processing—low SNR underwater acoustic signal classification method (LSUASC)—based on intrinsic modal features maintaining dimensionality reduction. Using the LSUASC method, the underwater acoustic signal was first transformed with the Hilbert-Huang Transform (HHT) and the intrinsic mode was extracted. the intrinsic mode was then transformed into a corresponding Mel-frequency cepstrum coefficient (MFCC) to form a multidimensional feature vector of the low SNR acoustic signal. Next, a semi-supervised fuzzy rough Laplacian Eigenmap (SSFRLE) method was proposed to perform manifold dimension reduction (local sparse and discrete features of underwater acoustic signals can be maintained in the dimension reduction process) and principal component analysis (PCA) was adopted in the proces of dimension reduction to define the reduced dimension adaptively. Finally, Fuzzy C-Means (FCMs), which are able to classify data with weak features was adopted to cluster the signal features after dimensionality reduction. The experimental results presented here show that the LSUASC method is able to classify low SNR underwater acoustic signals with high accuracy.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hereditary Equality of Domination and Exponential Domination in Subcubic Graphs
Autorzy:
Chen, Xue-Gang
Wang, Yu-Feng
Wu, Xiao-Fei
Tematy:
dominating set
exponential dominating set
subcubic graphs
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Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Powiązania:
https://bibliotekanauki.pl/articles/32324524.pdf  Link otwiera się w nowym oknie
Opis:
Let γ(G) and γe(G) denote the domination number and exponential domination number of graph G, respectively. Henning et al., in [Hereditary equality of domination and exponential domination, Discuss. Math. Graph Theory 38 (2018) 275–285] gave a conjecture: There is a finite set ℱ of graphs such that a graph G satisfies (H) = γe(H) for every induced subgraph H of G if and only if G is ℱ-free. In this paper, we study the conjecture for subcubic graphs. We characterize the class ℱ by minimal forbidden induced subgraphs and prove that the conjecture holds for subcubic graphs.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure and Magnetic Exchange Interaction in Fe₂NiAs Compound
Autorzy:
Wei, Xiao-Ping
Zhang, Ya-Ling
Sun, Xiao-Wei
Song, Ting
Zhu, Xing-Feng
Tematy:
71.20.Lp
71.20.Gj
71.20.-b
77.80.B-
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1033418.pdf  Link otwiera się w nowym oknie
Opis:
Using the spin-polarized relativistic Korringa-Kohn-Rostoker method, we study the electronic and magnetic properties of Fe₂NiAs compound with the Hg₂CuTi structure. Electronic calculations reveal the d-d orbital hybridization taking an important role in the compound. The calculated magnetic moments, which contain the spin and orbital moments, are primarily carried by Fe atoms located in A and B sites. The orbital moment of Fe₂NiAs system is rather small due to the cause of orbital quenching, implying a weak spin-orbit coupling. Simultaneously, we also study the influence of lattice constant on the magnetic moment, it is found that both spin and orbital moments are sensitive to the changes of lattice constants, i.e., the moments become larger as the expansion of lattice constant, indicating the enhancement of spin-orbit coupling effect. In addition, we investigate the magnetic interactions between the constituents to obtain the Heisenberg exchange coupling parameters. It is noted that the interactions are dominated by a strong exchange between Fe atoms. Finally, we acquire the Curie temperatures of Fe₂NiAs compound under different lattice constants by using mean field approximation.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal error modeling of spindle and dynamic machining accuracy reliability analysis of CNC machine tools based on IA and LHSMC
Autorzy:
Zhang, Ziling
Feng, Shuo
Ding, Yan
Mei, Xiao
Tao, Zhiqiang
Tematy:
electric spindle unit
thermal error
latin hypercube sampling monte carlo method
finite element simulation
machining accuracy reliability
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Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:
https://bibliotekanauki.pl/articles/2057984.pdf  Link otwiera się w nowym oknie
Opis:
Machining accuracy reliability as a key index of CNC machine tools is seriously influenced by the geometric and thermal errors. In the paper, a spindle unit thermal error modeling and machining accuracy reliability analysis method is proposed. By analyzing the heat generation mechanism, a thermal error model was developed to describe the thermal deformation of the electric spindle. Based on the immune algorithm (IA), the heat generation power and the heat transfer coefficient were optimized, and the thermal error was obtained by finite element thermal-mechanical coupling. By adopting the multi-body system theory (MBS), a dynamic machining accuracy model was put forward including the geometric and thermal errors. Based on the Latin hypercube sampling Monte Carlo method (LHSMC), a machining accuracy reliability analysis method was proposed to characterize the machining accuracy reliability considering the geometric and thermal errors. The method was employed to a machine tool, and the experimental results indicate the verification and superiority of the method.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the behavior of streamwise vortices formed between leading edge tubercles in a compressor cascade
Autorzy:
Zheng, Tan
Qiang, Xiao-Qing
Teng, Jin-Fang
Feng, Jin-Zhang
Tematy:
compressor cascade
flow separation
leading edge tubercles
streamwise vortices
formation mechanism
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/281149.pdf  Link otwiera się w nowym oknie
Opis:
A study has been carried out to investigate the formation mechanism and development of streamwise vortices induced by leading edge tubercles in a high speed compressor cascade. The preliminary assessment of the cascade performance in terms of the total pressure loss coefficient shows that the loss reduction is achieved at high incidence angles. A smaller wavelength leads to higher additional losses at the design point, but gives rise to a greater loss reduction at high incidence angles. The modified cascade with a tubercle wavelength of 4% chord achieves the maximum loss reduction of 36.1% at i = 10◦ , as well as the stall angle improvement of 27.6%. The formation mechanism of streamwise vortices is elaborated on the basis of the streamwise vorticity equation, in which the streamwise turning terms may be responsible for the generation of streamwise vortices. Slices of streamwise vorticity at various streamwise locations, combined with vorticity strength distributions, have been presented to study the development of streamwise vortices. The counter-rotating vortices are divided into the crest-induced streamwise vortices (CSVs) and trough-induced streamwise vortices (TSVs). A streamwise vortex pair formed from a part of the CSV sheets behind troughs, is gradually entrained by the TSV pair along the streamwise direction. In addition, the tubercles with a smaller wavelength result in higher streamwise vorticity strength with which the streamwise vortices interact with the flow separation more sufficiently and delay the separation to a greater extent.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy-saving optimal scheduling under multi-mode “source-network-load-storage” combined system in metro station based on modified Gray Wolf Algorithm
Autorzy:
Tian, Jingjing
Qian, Yu
Zhao, Feng
Mo, Shenglin
Xiao, Huaxuan
Zhu, Xiaotong
Liu, Guangdi
Tematy:
bilevel optimization
grey wolf optimization algorithm
multi-mode
peak shaving
valley-filling
source-network-load-storage
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Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:
https://bibliotekanauki.pl/articles/59111824.pdf  Link otwiera się w nowym oknie
Opis:
Aiming to address power consumption issues of various equipment in metro stations and the inefficiency of peak shaving and valley filling in the power supply system, this study presents an economic optimization scheduling method for the multi-modal “source-network-load-storage” system in metro stations. The proposed method, called the Improved Gray Wolf Optimization Algorithm (IGWO), utilizes objective evaluation criteria to achieve economic optimization. First, construct a mathematical model of the “source network-load-storage” joint system with the metro station at its core. This model should consider the electricity consumption within the station. Secondly, a two-layer optimal scheduling model is established, with the upper model aiming to optimize peak elimination and valley filling, and the lower model aiming to minimize electricity consumption costs within a scheduling cycle. Finally, this paper introduces the IGWO optimization approach, which utilizes meta-models and the Improved Gray Wolf Optimization Algorithm to address the nonlinearity and computational complexity of the two-layer model. The analysis shows that the proposed model and algorithm can improve the solution speed and minimize the cost of electricity used by about 5.5% to 8.7% on the one hand, and on the other hand, it improves the solution accuracy, and at the same time effectively realizes the peak shaving and valley filling, which provides a proof of the effectiveness and feasibility of the new method.
Dostawca treści:
Biblioteka Nauki
Artykuł

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