Informacja

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

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Chen, Xiao" wg kryterium: Autor

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 30
Tytuł:
A Multi-Layer Micro-Perforated Panel Structure Based on Curled Space for Broadband Sound Absorption at Low Frequencies
Autorzy:
Chu, Jiaming
Liang, Xiao
Yang, Zhen
Liang, Haofeng
Chen, Tao
Su, Liang
Zhou, Zhuo
Powiązania:
https://bibliotekanauki.pl/articles/31339792.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
micro-perforated plate
curled space
broadband sound absorption
complex frequency plane method
Opis:
In this paper, we propose a multi-layer micro-perforated panel structure based on a curled space for broadband sound absorption at low frequencies, which increases the number of perforated panel layers in a limited space using a curled space. The absorption coefficients of the structure under plane wave conditions were calculated using the transfer matrix method and the finite element method. It is demonstrated that the multilayer micro-perforated panel structure can ensure high absorption (consistently over 90%) in the frequency range of 400~5000 Hz. The sound absorption mechanism of the multi-layer micro-perforated panel structure is investigated by using the acoustic impedance along with the reflection coefficient of the complex frequency surface. In addition, we also discuss the effects of the micro-perforated panel parameters on the structural sound absorption coefficient. The results show that the proposed multi-layer micro-perforated panel structure provides an excellent solution for sound absorption in a limited space.
Źródło:
Archives of Acoustics; 2023, 48, 4; 529-538
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel combinational evaluation method of voltage and reactive power in regional power grid containing renewable energy
Autorzy:
Ji, Yuqi
Chen, Xuehan
Xiao, Han
Shi, Shaoyu
Kang, Jing
Wang, Jialin
Zhang, Shaofeng
Powiązania:
https://bibliotekanauki.pl/articles/1955201.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
adaptive weighting coefficient
combinational evaluation
renewable energy
typical scenarios
adaptacyjny współczynnik wagowy
ocena kombinacyjna
energia odnawialna
typowy scenariusz
Opis:
The output of renewable energy is strongly uncertain and random, and the distribution of voltage and reactive power in regional power grids is changed with the access to large-scale renewable energy. In order to quantitatively evaluate the influence of renewable energy access on voltage and reactive power operation, a novel combinational evaluation method of voltage and reactive power in regional power grids containing renewable energy is proposed. Firstly, the actual operation data of renewable energy and load demand are clustered based on the K-means algorithm, and several typical scenarios are divided. Then, the entropy weight method (EWM) and the analytic hierarchy process (AHP) are combined to evaluate the voltage qualified rate, voltage fluctuation, power factor qualified rate and reactive power reserve in typical scenarios. Besides, the evaluation results are used as the training samples for back-propagation (BP) neural networks. The proposed combinational evaluation method can calculate the weight coefficient of the indexes adaptively with the change of samples, which simplifies the calculation process of the indexes’ weight. At last, the case simulation of an actual regional power grid is provided, and the historical data of one year is taken as the sample for training, evaluating and analyzing. And finally, the effectiveness of the proposed method is verified based on the comparison with the existing method. The evaluated results could provide reference and guidance to the operation analysis and planning of renewable energy.
Źródło:
Archives of Electrical Engineering; 2021, 70, 4; 925-942
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel laccase from fresh fruiting bodies of the wild medicinal mushroom Tricholoma matsutake
Autorzy:
Xu, Lijing
Zhu, Mengjuan
Chen, Xiao
Wang, Hexiang
Zhang, Guoqing
Powiązania:
https://bibliotekanauki.pl/articles/1039125.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Tricholoma matsutake
wild mushroom
isolation
laccase
decolorization
Opis:
The knowledge about biological activities of constituents from medicinal mushrooms belonging to the genus Tricholoma is limited. A 59-kDa laccase has now been purified from fresh fruiting bodies of the mushroom Tricholoma matsutake. The purification protocol entailed ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, affinity chromatography on ConA-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. Of the various affinity and ion exchange chromatographic media employed, the laccase bound only on Con A-Sepharose. The activity of the laccase did not undergo major changes over the temperature range 20-80°C. However, all activity vanished following exposure to 100°C for 10 minutes. The enzyme activity varied only slightly over the pH range 3-5, with the optimal pH of 5, but exhibited a precipitous decline when the pH was increased to 6, and was undetectable at pH 8 and 9. The laccase showed activity in the decolorization of azo dyes without a mediator. Its N-terminal sequence demonstrated only slight resemblance to those of other mushroom laccases. The newly described laccase is distinctive from the previously isolated Tricholoma mushroom laccases in a number of aspects.
Źródło:
Acta Biochimica Polonica; 2015, 62, 1; 35-40
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel process for extraction of iron from a refractory red mud
Autorzy:
Ding, Wei
Xiao, Junhui
Peng, Yang
Shen, Siyue
Chen, Tao
Zou, Kai
Wang, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/1450194.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
red mud
sodium sulfate
segregation roasting
magnetic separation
iron recovery
Opis:
Red mud is a kind of solid waste produced during alumina extraction from bauxite. To extraction valuable iron from red mud, the technology of adding sodium sulfate-segregation roasting-magnetic separation to treat red mud was developed. During the paper, the effects of various process parameters on the extraction of iron by segregation roasting-magnetic separation were studied, and the phase transformation behavior and microstructure of iron are explored. Repeated test results showed that magnetic concentrate (mass percent), TFe of 80.29 % and overall iron recovery of 92.08 %was obtained. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicated that after the segregation roasting, the hematite was transformed into a new metal phase consisting mainly of metallic iron and magnetite. The addition of sodium sulfate during the segregation roasting can obviously improve the efficiency of segregation roasting-magnetic separation for iron extraction.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 125-136
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A unified calculation of the optical and EPR spectral data for the trigonal Cr³⁺ center in Cr³⁺-doped α-RbAl(SO₄)₂·12H₂O alum crystal
Autorzy:
Li, Xiao-Wu
Mei, Yang
Wei, Cheng-Fu
Zheng, Wen-Chen
Powiązania:
https://bibliotekanauki.pl/articles/1070555.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
76.30.Fc
78.40.Ha
78.55.Hx
Opis:
The optical band positions and the spin-Hamiltonian parameters (g factors g_{∥}, g_{⊥}, and zero-field splitting parameter D) of alum α-RbAl(SO₄)₂·12H₂O:Cr³⁺ are calculated by diagonalizing the 120× 120 complete energy matrix based on the two-spin-orbit-coupling-parameter model. The model takes into account not only the contributions due to the spin-orbit-coupling parameter of central d^{n} ion in the conventional crystal field theory, but also those due to ligands via covalence effect. The calculation indicates that the fourteen observed spectral data (eleven optical band positions and three spin-Hamiltonian parameters) can be reasonably and uniformly explained with four adjustable parameters (the Racah parameters B, C, intrinsic parameter A̅₄(R) in the superposition model, and the trigonal distortion angle β). The calculations also suggest that contrary to the previous findings, the trigonal distortion of Cr³⁺ (entering the Al³⁺ site in the host crystal) center in α-RbAl(SO₄)₂·12H₂O is induced mainly by the oxygen (or water) octahedron around the Cr³⁺ ion rather than the more distant neighbors.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 340-343
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An adaptive k nearest neighbour method for imputation of missing traffic data based on two similarity metrics
Autorzy:
Wang, Yang
Xiao, Yu
Lai, Jianhui
Chen, Yanyan
Powiązania:
https://bibliotekanauki.pl/articles/949848.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
missing traffic data
similarity metrics
K-nearest neighbour method
stochastic characteristics
metoda porównywania danych
metryki podobieństwa
metoda najbliższego sąsiada
cechy stochastyczne
Opis:
Traffic flow is one of the fundamental parameters for traffic analysis and planning. With the rapid development of intelligent transportation systems, a large number of various detectors have been deployed in urban roads and, consequently, huge amount of data relating to the traffic flow are accumulatively available now. However, the traffic flow data detected through various detectors are often degraded due to the presence of a number of missing data, which can even lead to erroneous analysis and decision if no appropriate process is carried out. To remedy this issue, great research efforts have been made and subsequently various imputation techniques have been successively proposed in recent years, among which the k nearest neighbour algorithm (kNN) has received a great popularity as it is easy to implement and impute the missing data effectively. In the work presented in this paper, we firstly analyse the stochastic effect of traffic flow, to which the suffering of the kNN algorithm can be attributed. This motivates us to make an improvement, while eliminating the requirement to predefine parameters. Such a parameter-free algorithm has been realized by introducing a new similarity metric which is combined with the conventional metric so as to avoid the parameter setting, which is often determined with the requirement of adequate domain knowledge. Unlike the conventional version of the kNN algorithm, the proposed algorithm employs the multivariate linear regression model to estimate the weights for the final output, based on a set of data, which is smoothed by a Wavelet technique. A series of experiments have been performed, based on a set of traffic flow data reported from serval different countries, to examine the adaptive determination of parameters and the smoothing effect. Additional experiments have been conducted to evaluate the competent performance for the proposed algorithm by comparing to a number of widely-used imputing algorithms.
Źródło:
Archives of Transport; 2020, 54, 2; 59-73
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An alternative ballistic limit equation for the Whipple shield in the shatter regime, based on characteristics of the large central fragment
Alternatywne równanie do kalkulacji balistycznych granic tarczy Whipplea w „trybie roztrzaskania”, oparte na charakterystyce dużego odłamka centralnego
Autorzy:
Wen, Ken
Di, De-ning
Chen, Xiao-wei
Powiązania:
https://bibliotekanauki.pl/articles/36440242.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
Whipple shield
debris cloud
ballistic limit equation
large central fragment
fragment identification
tarcza Whipple'a
chmura odłamków
balistyczne równanie graniczne
fragment centralny
identyfikacja fragmentów
Opis:
In the shatter regime of a Whipple shield, a large central fragment makes a significant contribution to the damage-causing capacity of the debris cloud. Herein we present a feasibleschemefor theidentification and measurement of this large central fragment and propose an alternative approach to the ballistic limit equation (BLE) for the Whipple shield, deducing an alternative ballistic limit in the shatter regime based on the large central fragment’s characteristics. This alternative BLE is compared with the phenomenological Whipple BLE, the JSC Whipple BLE and the Ryan curve. Our alternative BLE, modified at the incipient fragmentation and completed fragmentation point, is shown to agree well with experimental results.
W tzw. trybie „roztrzaskania” tarczy Whipple'a, duży centralny fragment obiektu zderzeniowego odpowiada za znaczną część ogólnej zdolności chmury odłamków do powodowania zniszczeń. W niniejszym opracowaniu przedstawiono realny schemat identyfikacji i pomiaru tego dużego centralnego fragmentu i na tej podstawie zaproponowano alternatywne podejście do balistycznego równania granicznego (BLE) dla tarczy Whipple'a. Wyznaczono alternatywną graniczną wartość balistyczną w reżimie roztrzaskania na podstawie charakterystyki centralnego fragmentu.Takie alternatywne podejście jest porównane z fenomenologicznym równaniem dla tarczy Whipple'a, z równaniem JSC Whipple oraz i z tzw. krzywą Ryana. Proponowane alternatywne równanie BLE, zmodyfikowane w punkcie początkowej i końcowej fragmentacji, wykazuje dobry poziom spójności z wynikami eksperymentalnymi.
Źródło:
Transactions on Aerospace Research; 2021, 2 (263); 12-29
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated model of production scheduling and maintenance planning under imperfect preventive maintenance
Model zintegrowany harmonogramowania produkcji i planowania obsługi technicznej w ramach niepełnej konserwacji zapobiegawczej
Autorzy:
Chen, X.
Xiao, L.
Zhang, X.
Xiao, W.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/301817.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
aperiodic imperfect preventive maintenance
production scheduling
maintenance planning
immune clonal selection algorithm
total profit
nieokresowa niepełna konserwacja zapobiegawcza
harmonogramowanie produkcji
planowanie konserwacji
algorytm odpornościowej selekcji klonalnej
całkowity zysk
Opis:
For a successful company, machines are always required to work continuously to make more profit in a certain period. However, machines can be unavailable due to the scheduled maintenance activities or unexpected failures. Hence, a model connected production scheduling with maintenance planning for a production line which is composed of multiple machines is developed. Suppose preventive maintenance is imperfect and cannot renew all the machines. Age reduction factor and hazard rate increase factor are introduced to illustrate the imperfect character. Aperiodic preventive maintenance policy is adopted. Replacement as perfect maintenance could restore the machine “as good as new”. When and whether to perform replacement is based on a cost-time rate function which is defined to judge whether or not the preventive maintenance is economical. The objective of the joint model is to maximize the total profit which is composed of production value, production cost, maintenance cost (including the preventive maintenance cost and replacement cost), and tardiness cost (which is related to the job sequence and maintenance activities). To optimize the objective, immune clonal selection algorithm is utilized. The proposed model is validated by a numerical example.
Aby firma mogła działać z powodzeniem i przynosić większe zyski w danym okresie czasu, zainstalowane w niej maszyny muszą pracować w sposób nieprzerwany. Niestety, z powodu planowych działań obsługowych lub nieoczekiwanych awarii, maszyny są czasami wyłączane z produkcji. Dlatego też w niniejszym artykule opracowano model łączący harmonogramowanie produkcji z planowaniem obsługi technicznej dla linii produkcyjnej złożonej z wielu maszyn. W pracy założono, że konserwacja zapobiegawcza jest niepełna i nie prowadzi do odnowy wszystkich maszyn. Aby zilustrować jej niepełny charakter, wprowadzono pojęcia czynnika redukcji wieku oraz czynnika wzrostu wskaźnika zagrożenia. Przyjęto politykę nieokresowej konserwacji zapobiegawczej. Wymiana jako forma pełnej konserwacji pozwala na przywrócenie maszyny do stanu "fabrycznej nowości". Kiedy i czy należy przeprowadzić wymianę zależy od funkcji wskaźnika kosztu w stosunku do czasu, który pozwala ocenić, czy konserwacja zapobiegawcza jest opłacalna. Model zintegrowany ma na celu maksymalizację całkowitego zysku, który jest wypadkową wartości produkcji, kosztów produkcji, kosztów obsługi (w tym kosztów konserwacji zapobiegawczej oraz kosztów wymiany) i kosztów nieterminowego zakończenia zadania (ang. lateness, związanych z kolejnością wykonywanych zadań i czynności obsługowych). Aby zoptymalizować opisany cel, wykorzystano algorytm odpornościowej selekcji klonalnej Proponowany model zweryfikowano na przykładzie liczbowym.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 1; 70-79
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of chromatographic plate theory on the weathered crust elution-deposited rare earth ore with carboxylate
Autorzy:
Zhang, Zhenyue
Wang, Guangshuai
Li, Chunhua
Chi, Ruan
Long, Fei
Chen, Zhuo
Chi, Xiao Wang
Liu, Defeng
Powiązania:
https://bibliotekanauki.pl/articles/1446022.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
weathered crust elution-deposited rare earth ore
carboxylate ammonium
mass transfer
theory plate
rare earth
Opis:
To improve the leaching process of rare earth and reduce the impurities in the leachate, the carboxylate ammonium, such as ammonium acetate, ammonium citrate and ammonium tartrate, were selected as lixiviant to compare the effects of concentration, flow rate, pH and temperature on leaching mass process of rare earth and aluminum. Meanwhile, the leaching behaviors of rare earth and aluminum leached by three kinds of carboxylate ammonium were analyzed by chromatographic plate theory. The relationship between the flow rate and height equivalent (HETP) could fit well with the Van Deemter equation and there was an optimal flow rate (uopt) for the leaching of the rare earth and aluminum. Besides, the conditions of carboxylate ammonium lixiviant were optimized. The optimum concentrations of ammonium acetate, ammonium tartrate and ammonium citrate were 15 g/L, 25 g/L and 5 g/L respectively, the leaching flow rate was 0.50 mL/min, the pH value was approximatively 7.00 and the leaching temperature was 293 K to 303 K. At these conditions, the mass transfer efficiencies of three ammonium carboxylates for rare earth and aluminum was in the order of ammonium acetate > ammonium tartrate > ammonium citrate. Moreover, the ammonium acetate could commendably inhibit aluminum ions entering the lixivium.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 48-62
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bivariate distribution characteristics of spatial structure in five different Pinus massoniana forests
Autorzy:
Zhang, Ren-bo
Ding, Gui-jie
Luo, Xiao-man
Chen, Mo-fang
Powiązania:
https://bibliotekanauki.pl/articles/956829.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
uniform angle index
mingling
dominance
structure-based forest management
Opis:
Bivariate distribution is an effective approach to spatial structure analysis. Combined with two of the three structure parameters (uniform angle index (W), dominance (U) and mingling (M)), the structural bivariate characteristics of five different Pinus massoniana forests were explored in this study. Our objective was to provide a theoretical direction for structure-based and detailed management in P. massoniana forests. The bivariate traits showed that mixed artificial or secondary forests predominated by P. massoniana trees do not typically achieve the highest mingling level. Trees under extreme mingling conditions were rare and typically comprised of non-dominant species instead of dominant ones in P. massoniana forests; these trees were generally overtopped and randomly distributed. Management implications can be extracted comparing the bivariate traits between all species and dominant species. The original community structure, development stage, and mixed-tree species number affect the univariate M and, furthermore, the two bivariate U-M and W-M distributions in mixed forests. Forest type has little effect on all-species W-U traits compared to those of the dominant species. U-M traits should be adjusted first if the random frequency values are highest in W-U and W-M bivariate distribution, and it is necessary to determine whether these two bivariate traits shade the W univariate. Adjustments made based on bivariate distribution can reveal poor frequency combinations for foresters to target; this allows the simultaneous adjustment of dual aspects of forest structure based on one bivariate index. Our results show that bivariate distribution may provide very useful information for the management of P. massoniana and other forests.
Źródło:
Dendrobiology; 2017, 78; 75-84
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterized Microstructure and Electrical Properties of Hydrogenated Nanocrystalline Silicon Films by Raman and Electrical Conductivity Spectra
Autorzy:
Xiao-Yong, Gao
Jian-Tao, Zhao
Yu-Fen, Liu
Qing-Geng, Lin
Yong-Sheng, Chen
Jin-Hua, Gu
Shi-E, Yang
Jing-Xiao, Lu
Powiązania:
https://bibliotekanauki.pl/articles/1808127.pdf
Data publikacji:
2009-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.23.Cq
73.61.-r
Opis:
Microstructure and electrical properties of hydrogenated nanocrystalline silicon (nc-Si:H) film deposited on glass substrate at low temperature were characterized by average grain size, crystallinity, and dark electrical conductivity data obtained from the Raman and electrical conductivity spectroscopy, respectively. The average grain size, crystallinity and electrical conductivity have a similar change with substrate temperature. A threshold substrate temperature determined by silane concentration appears in their corresponding spectroscopy vs. substrate temperature. The dependence of crystallinity, average grain size and electrical conductivity on substrate temperature were accounted for by surface diffusion model and heterojunction quantum dot model, respectively.
Źródło:
Acta Physica Polonica A; 2009, 115, 3; 738-741
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complete Diagonalization Calculation of the Optical and EPR Data for the Tetragonal $Cu^{2+}$ Center in $Cu^{2+}$-Doped ZnSe Nanocrystals
Autorzy:
Wu, Xiao-Xuan
Zheng, Wen-Chen
Powiązania:
https://bibliotekanauki.pl/articles/1399131.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Fc
71.70.Ch
78.40.Fy
75.10.Dg
Opis:
By using the complete diagonalization (of energy matrix) method based on the cluster approach (where the admixture between the d orbitals of $d^{n}$ ion and p orbitals of ligands due to covalence effect is considered), the optical and electron paramagnetic resonance data (three optical band positions and four EPR parameters $g_{∥}$, $g_{⊥}$, $A_{∥}$, $A_{⊥}$) are calculated for the tetragonal $Cu^{2+}$ center in $Cu^{2+}$-doped poly vinyl alcohol (PVA) passivated ZnSe nanocrystals with the defect model of $Cu^{2+}$ in the interstitial octahedral site in ZnSe. The calculated results are near the experimental values. The tetragonal elongation of the $Cu^{2+}$ octahedral cluster in ZnSe nanocrystals is obtained. The results are discussed.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 795-798
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Experiments of A New Internal Cone Type Traveling Wave Ultrasonic Motor
Autorzy:
Chen, Ye
Yang, Junlin
Li, Liang
Xiao, Shihao
Powiązania:
https://bibliotekanauki.pl/articles/31339802.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ultrasonic motors
traveling wave
internal cone type
bending vibration
Opis:
In order to simplify the motor structure, to reduce the difficulty of rotor pre-pressure application and to obtain better output performance, a new internal cone type rotating traveling wave ultrasonic motor is proposed. The parametric model of the internal cone type ultrasonic motor was established by the ANSYS finite element software. The ultrasonic motor consists of an internal cone type vibrator and a tapered rotor. The dynamic analysis of the motor vibrator is carried out, and two in-plane third-order bending modes with the same frequency and orthogonality are selected as the working modes. The other advantages of this motor are that pre-pressure can be imposed by the weight of the rotor. The prototype was trial-manufactured and experimentally tested for its vibration characteristics and output performance. When the excitation frequency is 22260.0 Hz, the pre-pressure is 0.1 N and the peak-to-peak excitation voltage is 300 V, the maximum output torque of the prototype is 1.06 N · mm, and the maximum no-load speed can reach 441.2 rpm. The optimal pre-pressure force under different loads is studied, and the influence of the pre-pressure force on the mechanical properties of the ultrasonic motor is analyzed. It is instructive in the practical application of this ultrasonic motor.
Źródło:
Archives of Acoustics; 2023, 48, 3; 373-380
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Digital watermarking scheme based on curvelet transform and multiple chaotic maps
Autorzy:
Xiao, Yi
Xu, Ya-Chen
Zhou, Nan-Run
Lin, Zhen-Rong
Powiązania:
https://bibliotekanauki.pl/articles/27310097.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital watermarking
curvelet transform
multiple chaotic map
Opis:
The rapid development of digital products brings security issues. Digital watermarking technology is an important means to handle these problems. To enhance the imperceptibility of watermark and locate the possible tampering as well, a digital watermarking scheme based on curvelet transform is presented by combining with multiple chaotic maps. The host image is decomposed into three parts, i.e., coarse layer, detail layer and fine layer, with curvelet transform, and a robust watermark is embedded into the coarse layer for copyright protection of digital products. In addition, an authentication watermark is embedded into the fine layer to detect and locate the illegal changes. Simulation results show that the proposed digital watermarking scheme possesses acceptable robustness and security.
Źródło:
Optica Applicata; 2023, 53, 2; 291--305
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of the strip coal pillar models failure with different roof and floor conditions
Autorzy:
Qu, Xiao
Chen, Shaojie
Yin, Dawei
Liu, Shiqi
Powiązania:
https://bibliotekanauki.pl/articles/2073871.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kopalnia
filar węglowy
górnictwo odkrywkowe
“roof-strip coal pillar-floor” combined specimen
failure characteristics
acoustic emission
laboratory experiment
Opis:
In order to study the failure mechanism and characteristics for strip coal pillars, a monitoring device for strip coal pillar uniaxial compression testing was developed. Compression tests of simulated strip coal pillars with different roof and floor rock types were conducted. Test results show that, with increasing roof and floor strength, compressive strength and elastic modulus of “roof-strip coal pillar-floor” combined specimens increase gradually. Strip coal pillar sample destruction occurs gradually from edge to the interior. First macroscopic failure occurs at the edge of the middle upper portion of the specimen, and then develops towards the corner. Energy accumulation and release cause discontinuous damage in the heterogeneous coal-mass, and the lateral displacement of strip coal pillar shows step and mutation characters. The brittleness and burst tendency of strip coal pillar under hard surrounding rocks are more obvious, stress growth rate decreases, and the rapid growth acoustic emission (AE) signal period can be regarded as a precursor for instability in the strip coal pillar. The above results have certain theoretical value for understanding the failure law and long-term stability of strip coal pillars.
Źródło:
Archives of Mining Sciences; 2021, 66, 3; 475--490
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 30

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