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Wyświetlanie 1-9 z 9
Tytuł:
Camera-based PHM method in rotating machinery equipment micro-action scenarios
Autorzy:
Junfeng, An
Liu, Jiqiang
Zhen, Hao
Mengmeng, Lu
Powiązania:
https://bibliotekanauki.pl/articles/24200809.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
deep learning
condition monitoring
Rmcad
anomaly detection
defect early warning
Opis:
The health operation of rotating machinery guarantees safety of the project. To ensure a good operating environment, current subway equipment inspections frequency is high, resulting in a waste of resources. Small abnormal changes in mechanical equipment will also contribute to the development of mechanical component defects, which will ultimately lead to the failure of the equipment. Therefore, mechanical equipment defects should be detected and diagnosed as soon as possible. Through the use of graphic processing and deep learning, this paper proposes Rmcad Framework with three aspects: condition monitoring, anomaly detection, defect early warning. Using a network algorithm, this paper proposes an improved model that has the characteristics of two-stream and multi-loss functions, which improves the accuracy of detection. Additionally, a defect warning method is constructed to improve the perception ability of equipment before failure occurs and reduce the frequency of frequent maintenance by detecting anomalies according to the degree of opening.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 1; art. no. 10
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semi-quantitative analysis study of the impact of microwave treatment on fly ash
Autorzy:
Ma, Xian Yun
Nie, Yi Miao
Guo, Jia Le
Chen, Yang
Chang, Zhen Jia
Wang, Ling
Liu, Shu Xian
Wang, Long
Powiązania:
https://bibliotekanauki.pl/articles/27323647.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
microwave
fly ash
semi-quantitative analysis
adsorption
XRD refinement
infrared fitting
NMR
Opis:
Pre-processing provides an effective way for fly ash's high value-added utilization. However, the shortcomings of pre-processing methods such as grinding and flotation are apparent with many disadvantages that make it more challenging to use efficiently. Microwave heating helps the SiO2-Al.2O3 bond break, not only can make the structural change of the material can also promote the chemical reaction process. In the article, XRD, SEM, FT-IR, ammonia nitrogen adsorption, and other methods were used to analyze the changes in the properties of fly ash before and after microwave pre-treatment, the change in adsorption performance of fly ash before and after microwave treatment was analyzed. The study found that under microwave conditions of 600 W and 15 min, the adsorption rate of ammonia nitrogen by fly ash reached a maximum of 29.67%. The intensity of mullite and amorphous diffraction peaks decreased after 20 min at 600 W. The Si-O-(Si, Al) and Si-O-(Si) bonds showed significant changes at 15 min and 20 min under 600 W conditions. Based on the results, the microwave conditions were selected at 600 W for different periods, and semi-quantitative analysis was carried out by XRD-Rietveld, infrared peak fitting, and nuclear magnetic resonance. The XRD-Rietveld analysis showed that the amorphous phase content reached 46.18% at 15 min. In the infrared peak fitting, the fitting area at 1300-900 cm-1 and 600-400 cm-1 peaks at 56.92% at 25 min and 17.5% at 15 min, respectively. The silicon-oxygen network's degree of connection and polymerization was reduced after 15 min of microwave treatment for the nuclear magnetic resonance analysis. By combining specific surface area measurements, it was discovered that the maximum specific surface area attained a value of 3.122 m2/g at 15 min.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 174897
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Manuscript Evidence for Suprabhātastava by Śrīharṣadeva: The Drepung Texts Critically Examined
Autorzy:
Liu, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/29520440.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Kultur Śródziemnomorskich i Orientalnych PAN
Tematy:
Suprabhātastava
Śrīharṣadeva
Buddhist hymns
Drepung Manuscripts
Opis:
The Suprabhātastava is one of the two hymns ascribed to King Śrīharṣadeva (c. 590–647 ce), who ruled over Kannauj. There are five modern editions of this text, which roughly follow eight extant Sanskrit manuscripts and a Tibetan translation. Recently, scholars discovered two unknown Sanskrit manuscripts of the text in Drepung Monastery. One of them has unique contents and readings. For this reason, the present article compares the said manuscript with other extant versions. In this respect, the article demonstrates that the newly discovered manuscripts belong to a different transmission lineage. Moreover, the article discusses the authorship and genre of the Suprabhātastava.
Źródło:
Acta Asiatica Varsoviensia; 2022, 35; 155-200
0860-6102
Pojawia się w:
Acta Asiatica Varsoviensia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on influencing factors of emergency power support for voltage source converter-based multi-terminal high-voltage direct current transmission system
Autorzy:
Li, Congshan
Zhen, Zikai
Sheng, Tingyu
Liu, Yan
Zhong, Pu
Zhang, Xiaowei
Powiązania:
https://bibliotekanauki.pl/articles/2172797.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coordinated control
emergency DC power support
influencing factors
VSC- MTDC transmission
Opis:
Voltage source converter-based multi-terminal high-voltage direct current (VSCMTDC) transmission system can realize a multi-point power supply, multi-drop power receiving, and mutual coordination between the converter stations to ensure the reliability of the transmission. Based on the PSCAD/EMTDC platform, a five-terminal DC transmission system model is established. According to the fast power regulation capability and overload capacity of theVSC-MTDC power transmission system, an analysis of additional emergency power support for a transmission system under large disturbance conditions was carried out. A new control strategy for emergency power support that introduces its basic principle is proposed in this paper. It uses the short-term overload capability of the DC system. By changing the power reserve of the converter station and the electrical distance between the converter stations, the influence of the power reserve and the electrical distance on the emergency power supply guarantee is analyzed the stability of the system is improved, thereby improving the sudden change of power caused by voltage fluctuations, and the feasibility of the control module is verified by PSCAD simulation. The simulation results show that when the system power supply suddenly changes, the converter stations at a short distance and large power reserve has a better effect on emergency power supply protection. A comparative study of the active power support of a single converter station and multiple converter stations is carried out. The research results show that the use of emergency power support in the DC transmission system has a good effect on maintaining the stability of the inter-connection system and the reliability of the power supply.
Źródło:
Archives of Electrical Engineering; 2022, 71, 4; 881--894
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
RFID tag group recognition based on motion blur estimation and YOLOv2 improved by Gaussian algorithm
Autorzy:
Li, Lin
Yu, Xiao-Lei
Liu, Zhen-Lu
Zhao, Zhi-Min
Zhang, Ke
Zhou, Shan-Hao
Powiązania:
https://bibliotekanauki.pl/articles/2051852.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
RFID
YOLOv2
neural network
GRNN
Opis:
Effective recognition of tags in the dynamic measurement system would significantly improve the reading performance of the tag group, but the blurred outline and appearance of tag images captured in motion seriously limit the effectiveness of the existing tag group recognition. Thus, this paper proposes passive tag group recognition in the dynamic environment based on motion blur estimation and improved YOLOv2. Firstly, blur angles are estimated with a Gabor filter, and blur lengths are estimated through nonlinear modelling of a Generalized Regression Neural Network (GRNN). Secondly, tag recognition based on YOLOv2 improved by a Gaussian algorithm is proposed. The features of the tag group are analyzed by the Gaussian algorithm, the region of interest of the dynamic tag is effectively framed, and the tag foreground is extracted; Secondly, the data set of tag groups are trained by the end-to-end YOLOv2 algorithm for secondary screening and recognition, and finally the specific locations of tags are framed to meet the effective identification of tag groups in different scenes. A considerable number of experiments illustrate that the fusion algorithm can significantly improve recognition accuracy. Combined with the reading distance, the research presented in this paper can more accurately optimize the three-dimensional structure of the tag group, improve the reading performance of the tag group, and avoid the interference and collision of tags in the communication channel. Compared with the previous template matching algorithm, the tag group recognition ability put forward in this paper is improved by at least 13.9%, and its reading performance is improved by at least 6.2% as shown in many experiments.
Źródło:
Metrology and Measurement Systems; 2022, 29, 1; 53-74
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of coupling effect between a unidirectional air waveguide and two cavities with one-way rotating state
Autorzy:
Gao, Yongfeng
He, Liu
Jiang, Zhen
Zhou, Jun
Shi, Yuejia
Bai, Wenfang
Powiązania:
https://bibliotekanauki.pl/articles/174202.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
waveguide-cavity coupling
magneto-optical photonic crystal
unidirectional air waveguide
one-way rotating state
finite element method
Opis:
In the paper we present an implementation of resonance coupling between a unidirectional air waveguide and two cavities with one-way rotating state in a two-dimensional dielectric photonic crystal and a magneto-optical photonic crystal. We theoretically calculate the dispersion curves of the line defect waveguide and the dispersion curves of waveguide-cavity interaction, respectively. Numerical simulations show that, via waveguide-cavity coupling, a series of interesting resonance phenomena can be generated in the system. By modifying direction of the applied external magnetic field, storing and discharging of photonic energy can be realized. Our work may provide a practical and useful guidance for optical communications.
Źródło:
Optica Applicata; 2020, 50, 1; 49-59
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on separation of fine-particle ilmenite and mechanism using flocculation flotation with sodium oleate and polyacrylamide
Autorzy:
Peng, Yang
Xiao, Junhui
Deng, Bing
Wang, Zhen
Liu, Nengyun
Yang, Daoguang
Ding, Wei
Chen, Tao
Wu, Qiang
Powiązania:
https://bibliotekanauki.pl/articles/1450088.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sodium oleate
polyacrylamide
synergistic effect
ilmenite
flocculation flotation
Opis:
In this paper, sodium oleate, polyacrylamide, soluble starch and sodium carboxymethyl cellulose were used as flocculants to study the flocculation and sedimentation behavior of microfine ilmenite. Sedimentation test shows that sodium oleate and polyacrylamide have good flocculation effect on ultrafine ilmenite. The flocculation rate of ilmenite can be further improved by the combination of sodium oleate and polyacrylamide. It was found that both flocculants could generate chemical adsorption with ilmenite surface, and they all react with $Fe^{3+}$ on ilmenite surface. However, sodium oleate reacts with $Fe^{3+}$ to form a water-insoluble iron oleate precipitate which coats the surface of the ilmenite and hinders the action of polyacrylamide and the remaining $Fe^{3+}$. This problem can be avoided by adding polyacrylamide followed by sodium oleate, and the flotation recovery can be increased significantly.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 161-172
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Ultraviolet Absorber on Photo-Degradation of Epoxy Coating Studied by Slow Positron Beam
Autorzy:
Wang, Zheng
Liu, Fuwei
Li, Jingjing
He, Chunqing
Peng, Xiangyang
Huang, Zhen
Fang, Pengfei
Powiązania:
https://bibliotekanauki.pl/articles/1033239.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
epoxy coating
photo-degradation
ultraviolet absorber
slow positron beam
microstructure
Opis:
The photo-degradation progress of epoxy coating and the effect of ultraviolet absorber under UV-B irradiation have been investigated in slow positron beam and by the Fourier transform infrared spectrometer. After 120 h of irradiation, the value of S parameter in sample bulk is reduced while compared with the virgin sample. The result is mostly due to post-cure process happening in this initial irradiation stage. As the irradiation time increases to 360 h, the S parameter decreases sharply. This is due to the growth of carbonyl group and the generation of free radical. After 528 h or longer time of irradiation, a very low S value was obtained near sample surface, indicating the formation of a dead surface layer. Positron results also reveal that the addition of ultraviolet absorber suppresses the development of the dead layer after long-term UV-B irradiation. Ultraviolet absorber has a suppressing effect on generation of polar groups towards sample bulk. The addition of ultraviolet absorber is a key factor that affects the photo-degradation of epoxy coating.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1523-1526
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Relationship between the Monomer Chain Length and the Electro-Optical Properties of Polymer Dispersed Liquid Crystals
Autorzy:
Liu, J.
Ozga, K.
Liu, X.
Zhen, Z.
Plucinski, K. J.
Szota, M.
Kityk, I. V.
Powiązania:
https://bibliotekanauki.pl/articles/958219.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
liquid crystal
electro-optical property
polymer dispersed
mesh size
response time
Opis:
Five polymers dispersed liquid crystalline (LC) films were fabricated using photo-polymerizable monomers with different lengths of carbon chains. These LC films have shown different electro-optical (EO) properties. Through their SEM pictures, the relationship between the linear electro-optical effect and the mesh size of the polymer network was explored. With the increase of number of photo-polymerizable monomers, the mesh size of the polymer network would become larger. So the liquid crystal molecules would be easily oriented in the electric field and therefore, the threshold voltage and saturation voltage would decrease. The open state response times were also reduced and the off state response times would be extended. The DFT simulations have shown principal role of the ground state dipole moments in the observed electro-optical efficiency.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 457-460
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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