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Design and Co-simulation of an Antiskid Brake System for a Civil Aircraft
Dawei Li,Mingxing Lin,Tao Zhang 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.3
To accelerate the design phases of the antiskid control system for a turboprop aircraft and to effectively ensure appropriate results, a brake-by-wire antiskid control system for a business aircraft is designed and investigated using a new virtual prototyping technology, which significantly reduces time, effort and cost. In contrast to traditional empirical formula methods, a multidisciplinary modeling co-simulation method has been proposed in this paper. The mathematical modeling process and antiskid control algorithm (Pressure Bias Modulation–Proportional–Integral Derivative) were analyzed and adopted. The co-simulation model was designed based on multi-body dynamic and multidisciplinary approach. The simulation results were compared with measured data sampled from an inertial platform test rig. The simulation results and physical experiment results proved the efficiency of the overall system.
Dawei Jiang,Jiasheng Li,Xingzhan Li,Chaodong Deng,Pinkuan Liu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2
The sheet current model considering the end effects is applied to design a sixdegree-of-freedom (6-DOF) active vibration isolation system (AVIS) driving by the voice coil motors (VCMs). Compared with the charge model, the sheet current method represents higher calculation efficiency. Then, the hybrid functions (HFs) are employed to identify the multi-input and multi-output (MIMO) AVIS, and the identification parameters are used to design the controller. To promote the control performance, the composite nonlinear feedback (CNF) controller is designed based on the identification parameters. Consequently, the simulations and experiments are carried out, compared with PID controller, the CNF controller shows quicker response and smaller overshoot, i.e., the CNF controller achieves the dynamic damping ratio during the control. Thus, the experimental results demonstrate the better performance of the CNF controller.
Li, Dawei,Cao, Jiaqing,Bi, Xiuli,Xia, Xichun,Li, Wei,Zhao, Yuqing The Korean Society of Ginseng 2014 Journal of Ginseng Research Vol.38 No.1
Background: Panax notoginseng has been used as a general tonic agent to invigorate human body for millennia in China and continued to be used until present. Methods: Some chromatographic methods were performed to isolate pure triterpenoids, and their structures were determined by nuclear magnetic resonance (NMR) experiments. Anti-diabetes activities of isolated compounds were evaluated through their inhibitory activity of protein tyrosine phosphatase 1B (PTP1B) enzyme. Results and Conclusion: Three new dammarane-type triterpenoids, notoginsenoside-LX (1), notoginsenoside-LY (2), and notoginsenoside-FZ (3) together with eighteen known compounds were isolated from the Panax notoginseng leaves. The structure-activity relationship of the compounds with dammaranetype triterpenoids and their PTP1B inhibitory activity were also reported. Results showed that compounds 2, 15, 20, and 21 can significantly inhibit the enzyme activity of PTP1B in a dose-dependent manner, with inhibitory concentration 50 ($IC_{50}$) values of $29.08{\mu}M$, $21.27{\mu}M$, $28.12{\mu}M$, and $26.59{\mu}M$, respectively. The results suggested that Panax notoginseng leaves might have potential as a new therapeutic agent for the treatment of diabetes.
Sinusoidal Back-EMF of Vernier Permanent Magnet Machines
Li, Dawei,Qu, Ronghai Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.1
Sinusoidal back-EMF waveform of vernier Permanent Magnet (PM) machines is analyzed in this paper. An analytical expression of Electromotive Force (EMF) of electric machines including vernier machines is developed to analyze EMF harmonics, and the effect of vernier PM machine pole ratio, the ratio of number of rotor poles to stator poles, on the EMF waveform. Moreover, this paper represents several Finite Element Analysis (FEA) models to verify the analysis based on the proposed expression, and the effect of tooth width ratio, which is the ratio of tooth width to tooth pitch, on back-EMF of vernier PM machines, and optimal tooth width ratio is obtained and verified by FEA. Finally, this paper makes comparisons between EMF waveform of vernier PM machines and that of traditional PM machines from the point of view of analytical EMF expression.
Dawei Li,Jiaqing Cao,Xiuli Bi,Xichun Xia,Wei Li,Yuqing Zhao 고려인삼학회 2014 Journal of Ginseng Research Vol.38 No.1
Background: Panax notoginseng has been used as a general tonic agent to invigorate human body for millennia in China and continued to be used until present. Methods: Some chromatographic methods were performed to isolate pure triterpenoids, and their structures were determined by nuclear magnetic resonance (NMR) experiments. Anti-diabetes activities of isolated compounds were evaluated through their inhibitory activity of protein tyrosine phosphatase 1B (PTP1B) enzyme. Results and Conclusion: Three new dammarane-type triterpenoids, notoginsenoside-LX (1), notoginsenoside-LY (2), and notoginsenoside-FZ (3) together with eighteen known compounds were isolated from the Panax notoginseng leaves. The structure-activity relationship of the compounds with dammaranetype triterpenoids and their PTP1B inhibitory activity were also reported. Results showed that compounds 2, 15, 20, and 21 can significantly inhibit the enzyme activity of PTP1B in a dose-dependent manner, with inhibitory concentration 50 (IC50) values of 29.08 mM, 21.27 μM, 28.12 μM, and 26.59 μM, respectively. The results suggested that Panax notoginseng leaves might have potential as a new therapeutic agent for the treatment of diabetes.
Research on prefabricated concrete beam-column joint with high strength bolt-end plate
Li Shufeng,Zhao Di,Li Qingning,Zhao Huajing,Zhang Jiaolei,Yuan Dawei 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.3
Many prefabricated concrete frame joints have been proposed, and most of them showed good seismic performance. However, there are still some limitations in the proposed fabricated joints. For example, for prefabricated prestressed concrete joints, prefabricated beams and prefabricated columns are assembled as a whole by the pre-stressed steel bar and steel strand in the beams, which brings some troubles to the construction, and the reinforcement in the core area of the joints is complex, and the mechanical mechanism is not clear. Based on the current research results, a new type of fabricated joint of prestressed concrete beams and confined concrete columns is proposed. To study the seismic performance of the joint, the quasi-static test is carried out. The test results show that the nodes exhibit good ductility and energy dissipation. According to the experimental fitting method and the “fixed point pointing” law, the resilience model of this kind of nodes is established, and compared with the experimental results, the two agree well, which can provides a certain reference for elasto-plastic seismic response analysis of this type of structure. Besides, based on the analysis of the factors affecting the shear capacity of the node core area, the formula of shear capacity of the core area of the node is proposed, and the theoretical values of the formula are consistent with the experimental value.
Dawei Li,Yongping Liu,Jun Gong,Yongqiao Wei,Gang Zhao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12
The traditional geometry of non-circular cylindrical gears provides a contact line between tooth surfaces. In a misaligned non-circular cylindrical gear drive, causing edge contacts that result in noise and vibration. The point contact of the tooth surface is achieved by modification of the driving gear in the longitudinal direction, in order to reduce the sensitivity of tooth surface contact to installation errors. The proposed longitudinal modification method is based on the application of a grinding worm by controlling the center distance of non-circular cylindrical gear and worm. Based on the gear meshing principle, a mathematical model of the tooth surfaces of non-circular cylindrical gears is established, and a parametric tooth surface equation with a unified expression is obtained. Tooth contact analysis (TCA) of non-circular cylindrical gears shows that the contact path and contact area on the tooth surface are shifted with the change of installation error, but still distributed in the middle of the tooth surface without creating edge contact. The transmission error is increased with the growth of installation error. Tooth modification in a longitudinal direction has an obvious improvement effect on the bad tooth contact condition, but too large a tooth modification parameter will make the tooth surface load distribution concentrated in a smaller area, which results in the decrease of gear load capacity.
Evolution of E. coli Phytase for Increased Thermostability Guided by Rational Parameters
( Jiadi Li ),( Xinli Li ),( Yuanming Gai ),( Yumei Sun ),( Dawei Zhang ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.3
Phytases are enzymes that can hydrolyze phytate and its salts into inositol and phosphoric acid, and have been utilized to increase the availability of nutrients in animal feed and mitigate environmental pollution. However, the enzymes’ low thermostability has limited their application during the feed palletization process. In this study, a combination of B-value calculation and protein surface engineering was applied to rationally evolve the heat stability of Escherichia coli phytase. After systematic alignment and mining for homologs of the original phytase from the histidine acid phosphatase family, the two models 1DKL and 1DKQ were chosen and used to identify the B-values and spatial distribution of key amino acid residues. Consequently, thirteen potential amino acid mutation sites were obtained and categorized into six domains to construct mutant libraries. After five rounds of iterative mutation screening, the thermophilic phytase mutant P56214 was finally yielded. Compared with the wild-type, the residual enzyme activity of the mutant increased from 20% to 75% after incubation at 90°C for 5 min. Compared with traditional methods, the rational engineering approach used in this study reduces the screening workload and provides a reference for future applications of phytases as green catalysts.