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Wyszukujesz frazę "Long, Wei" wg kryterium: Wszystkie pola


Wyświetlanie 1-5 z 5
Tytuł:
Research on Airflow Background Noise Suppression for Aeroacoustic Wind Tunnel Testing
Autorzy:
Li, Yuanwen
Li, Min
Feng, Daofang
Yang, Debin
Wei, Long
Powiązania:
https://bibliotekanauki.pl/articles/2141671.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aeroacoustic measurement
acoustic source localization
EEMD; background noise suppression
wind tunnel test.
Opis:
The microphone data collected in aeroacoustic wind tunnel test contains not only desired aeroacoustic signal but also background noise generated by the jet or the valve of the wind tunnel, so the desired aeroacoustic characteristics is difficult to be highlighted due to the low Signal-to-Noise Ratio (SNR). Classical cross spectral matrix removal can only reduce the microphone self-noise, but its effect is limited for jet noise. Therefore, an Airflow Background Noise Suppression method based on the Ensemble Empirical Mode Decomposition (ABNSEEMD) is proposed to eliminate the influence of background noise on aeroacoustic field reconstruction. The new method uses EEMD to adaptively separate the background noise in microphone data, which has good practicability for increasing SNR of aeroacoustic signal. A localization experiment was conducted by using two loudspeakers in wind tunnel with 80 m/s velocity. Results show that proposed method can filter out the background noise more effectively and improve the SNR of the loudspeakers signal compared with spectral subtraction and cepstrum methods. Moreover, the aeroacoustic field produced by a NACA EPPLER 862 STRUT airfoil model was also measured and reconstructed. Delay-and-sum beamforming maps of aeroacoustic source were displayed after the background noise was suppressed, which further demonstrates the proposed method’s advantage.
Źródło:
Archives of Acoustics; 2022, 47, 2; 241-257
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemical Information of Chitosan-Based Complex Extracted from Coincidence Doppler Broadening Spectra
Autorzy:
Cao, Xingzhong
Xia, Rui
Yang, Jing
Zeng, Minfeng
Wang, Baoyi
Yu, Runsheng
Wei, Long
Powiązania:
https://bibliotekanauki.pl/articles/1033908.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
64.70.km
82.30.Gg
Opis:
In recent years, coincidence Doppler broadening (CDB) of annihilation radiation measurement on polymeric system has been attracting special attention because of its unique elemental sensitivities in comparison to the traditional Doppler broadening measurement. In the present study, chitosan-Fe₃O₄ nanocomposite (CS-Fe₃O₄) and copper-chitosan (Cu-CS) complexes were prepared through a simple casting method from aqueous solution. The inclusion of Fe₃O₄ nanoparticles in the chitosan matrix is confirmed by X-ray diffraction. In order to obtain data about atomic composition of the annihilation site in the CS composites, CDB measurements were carried out. The normalized CDB ratio curve, which is related to the ratio between the momentum density distribution for the studied samples and pure CS, was displayed to illustrate the variation of ion cores of different elements present in the chitosan matrix. Our result confirms a contribution of active group available in chitosan molecules to the features in the high-momentum region of the CDB ratio curve. The findings show that the local chemical environment of the annihilation site in chitosan-based complexes could be estimated by such positron annihilation spectroscopic investigation.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1535-1537
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Academic and linguistic gains during a semester long study abroad: A cohort case study
Autorzy:
Cai, Wei
Li, Xiangrong
Liu, Meihua
Powiązania:
https://bibliotekanauki.pl/articles/780741.pdf
Data publikacji:
2013-12
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
gain
exchange program
academic
linguistic
Opis:
The present case study investigated university students’ academic and linguistic gains during a semester-long exchange program abroad. Thirty three third-year English majors from a Chinese university answered a battery of questionnaires and 13 of them participated in semi-structured interviews both prior to and after the program. Analyses of the data showed that the participants gained greatly from the exchange program both academically and linguistically. Based on the findings, some implications about exchange programs are discussed.
Źródło:
Studies in Second Language Learning and Teaching; 2013, 3, 4; 505-522
2083-5205
2084-1965
Pojawia się w:
Studies in Second Language Learning and Teaching
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shrink-Proof Treatment Parameter Optimisation of Cashmere Yarn
Autorzy:
Li, Long
Wang, Wei
Zhang, Xian
Wu, Lei
Yang, Dan
Powiązania:
https://bibliotekanauki.pl/articles/2171991.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
cashmere yarn
shrink-proof
potassium permanganate treatment
yarn shrinkage percentage
Opis:
Cashmere fiber has soft hand and good elasticity. However, it exhibits shrink because of its scale. In this work, cashmere yarn (38.26 tex) was treated using NaCl-KMnO4 to reduce the shrink of cashmere yarn. Orthogonal design and fuzzy comprehensive evaluation were used for optimizing treating parameters. Experimental results showed that the yarn shrink percentage of treated yarn was 0.56% which was less than that untreated yarn, and the treated yarn strength had a little drop compared with untreated yarn. The fiber scale outline of treated yarn could be observed by SEM, but the scale edge is blunt and irregular.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 3 (151); 57--60
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of grinding media on the flotation of copper-activated marmatite
Autorzy:
Long, Tao
Chen, Yao
Shi, Juanjuan
Chen, Wei
Zhu, Yangge
Zhang, Chonghui
Bu, Xianzhong
Powiązania:
https://bibliotekanauki.pl/articles/109857.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
grinding media
copper-activated marmatite
flotation separation
surface property
Opis:
How to avoid the shortage of floatability and non-purpose flotation in marmatite flotation is a big problem. This paper innovatively studies how to reduce these two negative phenomena from the perspective of grinding media. The effects of steel and stainless-steel balls on the flotation performance of copper-activated marmatite were investigated mainly through flotation tests, redox potential measurements, ion concentration tests, and XPS and FT-IR spectrum studies. The flotation results showed that the floatability of copper-activated marmatite remarkably decreased by using the steel ball in the grinding process, but it had a mere influence when stainless-steel medium was used. Redox potential measurements showed that the grinding environment of stainless-steel medium could exhibit a higher oxidizing potential than the steel grinding environment. Results from FTIR, XPS, and ion concentration measurements demonstrated that more ferric ions existed on the copper activated marmatite surface in the steel grinding environment than that in the stainless-steel environment. Ferric ions could further hinder the activation effect of copper ions on marmatite and result in decreased marmatite flotation. This research could potentially explain the mechanism of ferric ions in the grinding process, and it can be utilized to improve the flotation performance of marmatite ore through selecting suitable grinding media in ball mill operations.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 2; 229-237
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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