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- 저자 : ( Chaoyang Tan ) (검색결과 3 건)
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Jiqing Chen,Chaoyang Zhao,Qingsong Tang,Xu Liu,Zhikui Wang,Chengzhi Tan,Jiahua Wu,Teng Long 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.2
The improvement of the performance of the multi-joint manipulator control system is of great significance to improve the level of industrial automation. The existing sliding mode control methods are difficult to ensure the high-precision and fast-tracking of joints of a manipulator to the desired trajectory under low chattering control input. Therefore, a non-singular fast terminal sliding mode control method based on a nonlinear disturbance observer is proposed. In addition, a new non-singular fast terminal sliding mode surface is designed. The performance comparison method of the sliding mode surface proves its better control quality. Aiming at the problem of serious chattering, the nonlinear disturbance observer technology, and saturation function method are introduced to effectively weaken the chattering. Finally, taking the 3-DOF manipulator as the research object, a comparative simulation experiment is carried out in the MATLAB / Simulink environment. The results show that under the uncertainty of modeling error, external disturbance, and joint friction, the designed control method not only solves the problems of singular control input and serious chattering but also realizes the high-precision and fast-tracking of each joint to the desired trajectory. Thus, the effectiveness and feasibility of the design method are verified. The improvement of the performance of the multi-joint manipulator control system is of great significance to improve the level of industrial automation. The existing sliding mode control methods are difficult to ensure the high-precision and fast-tracking of joints of a manipulator to the desired trajectory under low chattering control input. Therefore, a non-singular fast terminal sliding mode control method based on a nonlinear disturbance observer is proposed. In addition, a new non-singular fast terminal sliding mode surface is designed. The performance comparison method of the sliding mode surface proves its better control quality. Aiming at the problem of serious chattering, the nonlinear disturbance observer technology, and saturation function method are introduced to effectively weaken the chattering. Finally, taking the 3-DOF manipulator as the research object, a comparative simulation experiment is carried out in the MATLAB / Simulink environment. The results show that under the uncertainty of modeling error, external disturbance, and joint friction, the designed control method not only solves the problems of singular control input and serious chattering but also realizes the high-precision and fast-tracking of each joint to the desired trajectory. Thus, the effectiveness and feasibility of the design method are verified.
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Meijing Liu,Junlong Tan,Shuang Li,Chaoyang Sun,Xiangning Liu,Hongtao Yang,Xiaogang Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00
Background The regulation of dose-dependent biological effects induced by biodegradation is a challenge for the production of biodegradable bone-substitute materials, especially biodegradable zinc (Zn) -based materials. Cytotoxicity caused by excess local Zn ions (Zn2+) from degradation is one of the factors limiting the wide application of Zn implants. Given that previous studies have revealed that delayed degradation of Zn materials by surface modification does not reduce cytotoxicity; in the present study, we explore whether preventing the entry of excess Zn2+ into cells may can reduce local Zn toxicity by applying Psoralen (PRL) to Zn implants and assessing its ability to regulate intracellular Zn2+ concentrations. Methods The effects of different concentrations of Zn2+ on cellular activity and cytotoxicity were investigated; briefly, we identified natural compounds that regulate Zn transporters, thereby regulating the concentrations of intracellular Zn2+, and applied them to Zn materials. Of these materials, PRL, a natural, tricyclic, coumarin-like aromatic compound that promotes the proliferation and differentiation of osteoblasts and enhances osteogenic activity, was loaded onto the surface of a Zn material using peptides and chitosan (CS), and the surface characteristics, electrochemical properties, and activity of the modified Zn material were evaluated. In addition, the ability of Zn + CS/pPRL implants to promote bone formation and accelerate large-scale bone defect repairs was assessed both in vitro and in vivo. Results We determined that 180 μM Zn2+ significantly induced pre-osteoblast cytotoxicity, and a 23-fold increase in Zrt- and Irt-like protein 4 (ZIP4) expression. We also found that PRL dynamically regulates the expression of ZIP4 in response to Zn2+ concentration. To address the problem of cytotoxicity caused by excessive Zn2+ in local Zn implants, PRL was loaded onto the surface of Zn implants in vivo using peptides and CS, which dynamically regulated ZIP4 levels, maintained the balance of intracellular Zn2+ concentrations, and enhanced the osteogenic activity of Zn implants. Conclusions This study reveals the importance of Zn2+ concentration when using Zn materials to promote bone formation and introduces a natural active ingredient, PRL, that can regulate intracellular Zn2+ levels, and thus may be clinically applicable to Zn implants for the treatment of critical bone defects.
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( Wenmei Wu ),( Xiwei Yuan ),( Xin Gao ),( Chaoyang Tan ),( Shunxiang Li ),( Dehong Xu ) 한국미생물생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.2
ρ-Hydroxyacetophenone is an important and versatile compound that has been widely used in medicine, cosmetics, new materials, and other fields. At present, there are two ways to obtain ρ-hydroxyacetophenone. One is to extract it from plants, such as Artemisia capillaris Thunb and Cynanchum otophyllum Schneid, and the other is to synthesize it by using chemical methods. Of these two methods, the second is the main one, although it has problems, such as flammable and explosive reagents, difficult separation of by-products, and harsh reaction conditions. To solve these issues, we adopted genetic engineering in this study to construct engineered Escherichia coli containing Hped gene or EbA309 gene. Whole-cell biotransformation was conducted under the same conditions to select the engineered E. coli with the higher activity. Orthogonal tests were conducted to determine the optimal biotransformation condition of the engineered E. coli. The results showed that the optimal condition was as follows: substrate concentration of 40 mmol/l, IPTG concentration of 0.1 mmol/l, an induction temperature of 25℃, and a transformation temperature of 35℃. Under this condition, the effects of transformation time on the ρ-hydroxyacetophenone concentration and cell growth were further studied. We found that as the transformation time extended, the ρ-hydroxyacetophenone concentration showed a gradually increasing trend. However, when the ρ-hydroxyacetophenone concentration increased to 1583.19 ± 44.34 mg/l in 24 h, cell growth was inhibited and then entered a plateau. In this research, we realized the synthesis of ρ-hydroxyacetophenone by biotransformation, and our findings lay a preliminary foundation for further improving and developing this method.
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