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- 저자 : Zhengnan Li (검색결과 4 건)
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Zhengnan Li,Miaomiao Zhang,Bin Zheng,Lidong Ma 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.10
The on-line measurement of medium thickness steel plate length is an important part of the hot rolling production. In this paper, an easy calibration method and a visual measurement method of laser stripe center extraction algorithm based on structured light are proposed to achieve on-line measurement of medium thickness steel plate length. Firstly, an experimental platform is designed and built to fix the intersecting visual fields of each camera. Secondly, the actual detection size of each camera's visual field is calibrated by the calibration method, and a fixed digital image processing range is set according to the thickness of the steel plate. Then, an adaptive image processing range extraction algorithm is proposed to further reduce the redundant image scanning. Moreover, we improve the traditional gray center of gravity method to achieve higher accuracy of laser stripe center extraction. Finally, in the laboratory, three medium thickness steel plates with different lengths are measured by the laser stripe extraction algorithm proposed in this paper. Experimental results show that the measurement error is within ± 1.5 mm, which proves that the algorithm has the characteristics of higher extraction accuracy and has certain engineering application value.
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Improved sliding mode control for mobile manipulators based on an adaptive neural network
Zhengnan Li,Lidong Ma,Zhijuan Meng,Jin Zhang,Yufeng Yin 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5
In this study, a wheeled mobile manipulator was modeled while considering the case of wheel-ground slippage. Considering the whole system, the number of states in the dynamic system equation was reduced by the kinematic solution, which facilitates the control of the system. For the system state equation, the improved sliding mode control method was applied, a flush continuous control term and a super-twisting algorithm were used to achieve the improved sliding mode control, and the gain of the super-twisting algorithm was adaptively controlled. The modeling error in the subsystem and the uncertain slippage were approximated by a neural network. The middle layer weights of the neural network were updated by the adaptive control law, and the stability of the system was demonstrated by a quadratic Lyapunov function. The simulation results show the superiority of the control method proposed in this paper by comparing them with results for the traditional sliding-mode control method and the improved sliding-mode control method.
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Li Xin,Wang Chunling,Liu Jiawei,Guo Yu,Cheng Fei,Yang Yanjie,Yan Zhengnan 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.6
Optimizing light conditions is critical for plant growth and seedling production in greenhouse, especially in seasons when the sunlight is insuffi cient. In the present study, tomato ( Solanum Lycopersicum cv. Fenbeibei) seedlings were grown at two levels of supplementary light duration of 6 h·d − 1 (short) (07:00–10:00 and 15:00–18:00) or 12 h·d − 1 (long) (04:00–10:00 and 15:00–21:00) provided by white light-emitting diodes (LEDs, white long and white short, WL and WS) or combinations of white and blue LEDs (white & blue long and white & blue short, WBL and WBS) with same supplementary daily light integral (at 5.5 mol m − 2 d − 1 ) after sowing, and tomato seedlings grown under sunlight only were set as the control. The per centages of light intensity provided by white and blue LEDs under the WB treatments were 85% and 15%, respectively. The results indicated that tomato seedlings grown under WBL treatment exhibited the lowest plant height and shortest hypocotyl length, which was decreased by 34.6% and 41.8%, respectively, compared with the control. The chlorophyll a, chlorophyll b, and total chlorophyll contents of tomato seedlings grown under WBL were signifi cant higher than those under other treat ments. The root fresh weight, root dry weight, and the stem fi rmness of the greenhouse-grown tomato seedlings under WBL were increased by 21.5%, 41.2%, and 38.6%, compared with those grown under WBS, respectively. The sucrose content of tomato seedlings under WBL was increased by 60.4%, compared with that under WL. In conclusion, 12 h·d − 1 supplementary light provided by combinations of white and blue LEDs led to compact morphological characteristics, superior mechanical properties, and satisfactory growth performance. Our fi ndings provide an available lighting strategy to obtain the desired morphological and quality properties of tomato seedlings grown in the seasons with insuffi cient light.
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Liu Chunlei,Li Peng,Ao Xiang,Lian Zhengnan,Liu Jie,Li Chenglong,Huang Minjun,Wang Liang,Zhang Zhongmin 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
Ligamentum flavum hypertrophy (LFH) is a major cause of lumbar spinal canal stenosis (LSCS). The pathomechanisms for LFH have not been fully elucidated. Isobaric tags for relative and absolute quantitation (iTRAQ) technology, proteomics assessments of human ligamentum flavum (LF), and successive assays were performed to explore the effect of clusterin (CLU) upregulation on LFH pathogenesis. LFH samples exhibited higher cell positive rates of the CLU, TGF-β1, α-SMA, ALK5 and p-SMAD3 proteins than non-LFH samples. Mechanical stress and TGF-β1 initiated CLU expression in LF cells. Notably, CLU inhibited the expression of mechanical stress-stimulated and TGF-β1-stimulated COL1A2 and α-SMA. Mechanistic studies showed that CLU inhibited mechanical stress-stimulated and TGF-β1-induced SMAD3 activities through suppression of the phosphorylation of SMAD3 and by inhibiting its nuclear translocation by competitively binding to ALK5. PRKD3 stabilized CLU protein by inhibiting lysosomal distribution and degradation of CLU. CLU attenuated mechanical stress-induced LFH in vivo. In summary, the findings showed that CLU attenuates mechanical stress-induced LFH by modulating the TGF-β1 pathways in vitro and in vivo. These findings imply that CLU is induced by mechanical stress and TGF-β1 and inhibits LF fibrotic responses via negative feedback regulation of the TGF-β1 pathway. These findings indicate that CLU is a potential treatment target for LFH.
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