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1

Study on tensile fracture failure of a steel plate with a surface crack

Chong Zhewen, Tao Jing, Xie Yuehui, Wu Dongrong, Li Tao

Journal of Theoretical and Applied Mechanics

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2023

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Vol. 61 nr 2

343--354

EN

In order to study the effect of different surface crack parameters on the fracture failure of steel plate, the model was established by FEM. The results showed that the edge surface crack has the greatest influence on the fracture failure of the steel plate, and for non-edge surface cracks, the central surface crack has the greatest influence on the fracture failure of the steel plate. The larger the a/t and the smaller the a/c, the easier the steel plate fracture failure occurs. The a/c has a certain influence on the variation law of K and the position where Kmax appears.

2

Fast attack detection method for imbalanced data in industrial cyber-physical systems

Huang Meng, Li Tao, Li Beibei, Zhang Nian, Huang Hanyuan

Journal of Artificial Intelligence and Soft Computing Research

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2023

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Vol. 13, No. 4

229--245

EN

Integrating industrial cyber-physical systems (ICPSs) with modern information technologies (5G, artificial intelligence, and big data analytics) has led to the development of industrial intelligence. Still, it has increased the vulnerability of such systems regarding cybersecurity. Traditional network intrusion detection methods for ICPSs are limited in identifying minority attack categories and suffer from high time complexity. To address these issues, this paper proposes a network intrusion detection scheme, which includes an information-theoretic hybrid feature selection method to reduce data dimensionality and the ALLKNN-LightGBM intrusion detection framework. Experimental results on three industrial datasets demonstrate that the proposed method outperforms four mainstream machine learning methods and other advanced intrusion detection techniques regarding accuracy, F-score, and run time complexity.

3

Finite Element Analysis and Experimental Study on the Thermal Resistance Characteristics of Motor Coolers

Xu Ke, Yang Jie, Tang Chuansheng, Zhao Qiang, Li Tao

Journal of Power Technologies

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2020

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Vol. 100, nr 3

279--289

EN

Motor coolers are operated with the coupling of temperature and pressure fields, in which the change rule is affected by multiple factors. In this study, the thermal resistance of the motorcooler was examined using the velocity coefficient method to reveal the influence of heat transfer and wind resistance. The temperature and pressure fields were analyzed using the finite element method based on the hydrodynamics and momentum theorem. By varying the heat transfer and wind resistance coefficients to reflect temperature and pressure characteristics, wind and water velocities were determined. Results demonstrate that the total convective heat transfer and wind resistance coefficients of the cooler model are sensitive to variations in face-to-face wind velocity, but not to those of the cooling water flow rate. When wind velocity increases from 0.8 to 5.19m/s, the total convective heat transfer increases by 1.85 times and wind resistance increases by 18.74 times. Variations in cooling water velocity has little effect on the Nusselt numberon the air side and the Euler number of the single row tube, which are multiplied with the increase of the Reynolds number. When the Reynolds number increases from 1020 to 6345, the Nusselt number increases by 2.05 times and the Euler numer decreases by 2.29 times. The results provide references for the design and performance testing of high-power motor coolers.

4

Control input limited switched reluctance motor with auxiliary sliding mode position tracking control

Tang Chuansheng, Zhang Gang, Yang Jie, Li Tao

Journal of Power Technologies

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2020

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Vol. 100, nr 4

341--350

EN

The drive system of a switched reluctance motor (SRM) is a nonlinear one with coupling between the rotor position, inductance, and flux linkage. Moreover, the system parameters change with the external environment such as temperature, humidity, and pressure. At the same time, uncertain factors including friction, torque fluctuation, and external interference in the system, reduce system stability and reliability. To effectively improve the influence of uncertain factors on the performance of an SRM system, this study proposes an auxiliary sliding position tracking method, under the condition of limited control input. First, the mathematical model of the system was established according to the structure and characteristics of an SRM.Second, an auxiliary sliding mode position tracking controller was designed by constructing the auxiliary system and utilizing the sliding mode control theory. Finally, the effectiveness and superiority of the proposed method were verified through comparison with proportional integral differential (PID) control and the traditional sliding mode control using simulation. Results demonstrate that under limited control input, the auxiliary sliding position tracking control method still delivers rapid and error-free tracking of the position and speed for the change of model parameters. The recommended scheme has a response time 2.9 times shorter than that of PID control. Furthermore,the steady-state errors of the PID control position and speed are 0.66 rad and 1.62 rad/s, respectively. The control input of the traditional sliding mode control has greater chattering than the proposed method. When the system has interference, the designed method under the condition of limited control in-put can achieve the desired tracking command within 1.7 s. The steady-state error is 0.0044 rad, and the steady-state accuracy of the developed scheme is 10.3 times higher than that of PID control. Therefore, the proposed method enjoys both high position tracking accuracy and strong robustness to external disturbances.

5

Effects of metal-ceramic anticorrosion coating on the performance of ballastless tracks at high temperature

Zhang Jiwen, Jiang Hailou, Ding Feng, Zhang Pingze, Zhou Fei, Li Tao, Duan Ning

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

329--342

EN

A highly reflective metal-ceramic anticorrosion coating is proposed to address temperature-induced track arching and concomitant damage of the China Railway Track System II ballastless tracks. The term ceramic refers to the inorganic phosphate coating binder and the metal pertains to the aluminite powder filler. Its thermal properties were studied through finite element modeling and heat radiation testing of uncoated and coated concrete samples and 1:1 ballastless track slab models. The metal–ceramic anticorrosion coating microstructure and constituent characterization were considered in its cooling efficacy analysis. The insulation temperature of the concrete test pieces increased as the thickness of the primer layer increased. At a primer layer thickness of 100 μm, 200 μm, and 300 μm, the corresponding insulation temperature was 8 °C, 18 °C, and 25 °C, respectively. Moreover, the temperature gradient, longitudinal stress, and vertical displacement of a track slab coated with a 300-μm metal-ceramic anticorrosion coating layer decreased by 29%, 57%, and 51.9%, respectively, which agreed well with the simulation results. The reduction in temperature transfer to the substrate, realized by the metal-ceramic anticorrosion coating, holds great promise for application in the construction industry.

6

Identification of forced degradation products of lacosamide by LC-QQLIT-MS and LC-IT/TOF-MS

Zhou Na, Li Tao, Ai Lianfeng, Guo Chunhai, Zhang Juan, Fu Shan, Wang Qiao

Acta Chromatographica

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2019

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Vol. 31, no. 1

12--18

EN

Lacosamide, a new type of antiepileptic drug, was subjected to forced degradation under the conditions of hydrolysis (acidic and alkaline), oxidation, dry heat, and photolysis to characterize its possible degradation products. The drug showed significant degradation under acidic, alkaline and oxidative conditions. The degradation products were separated on an Agilent Zorbax SB-C18 column with gradient elution using a mobile phase consisting of acetonitrile and ammonium acetate (0.002 mol/L) with formic acid as additive. A combination of liquid chromatography hybrid triple quadrupole-linear ion trap mass spectrometry (LC–QqLIT-MS) and liquid chromatography hybrid ion trap/time-of-flight mass spectrometry (LC-IT/TOF-MS) was used to identify degradation products. A total of 7 products including 4 novel degradation products were characterized. The mechanisms of degradation products of lacosamide were discussed. Application of the method to study degradation products of lacosamide provided fragment information, allowing further investigation of the degradation pathways and intrinsic stability of the drug.