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Dynamic modeling of a high-speed over-constrained press machine
Yejian Li,Yu Sun,Binbin Peng,Fengfeng Hu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7
This paper presents a study on the dynamic modeling of a high-speed over-constrained press machine. The main contribution of the paper is the development of an efficient approach to perform the dynamic analysis of a planner over-constrained mechanism. The key idea is the establishment of a more general methodology, which is to gain a deformation compatibility equation for the over-constrained mechanism on the basis of the deformation compatibility analysis at each position of the mechanisms. And this equation is then used together with the force/moment equilibrium equations obtained by the D’Alembert principle to form a total equation for the dynamics of the over-constrained mechanism. The approach is applied to a particular press machine to validate the effectiveness of the approach, and in the meantime to provide some useful information for the improvement of the design of this press machine.
Fengfeng Hu,Yu Sun,Binbin Peng 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10
An elastic dynamic model of high-speed multi-link precision press considering structural stiffness of rotation joints was established by the finite element method. In the finite element model, rotation joint was established by four bar elements with equivalent stiffness, and connected link was established by beam element. Then, the elastic dynamics equation of the system was established, and modal superposition method was used to solve the dynamic response. Compared with the traditional elastic dynamic model with perfect constraint of the rotation joints, the elastic dynamic response value of the improved model is larger. To validate the presented new method of elastic dynamics analysis with stiffness of rotation joints, a related test of slider Bottom dead center (BDC) position in different speed was designed. The test shows that the model with stiffness of rotation joints is more reasonable. So it provides a reasonable theory and method for dynamic characteristics research of sucha multi-link machine.
A new cascaded multilevel converter topology with energy exchange unit for STATCOM application
Rongfeng Yang,Yinglin Zhang,Binbin Li,Rong xu,Yong yu,Dianguo Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
The star-connected H-bridge cascaded converter has the disadvantage of capacitors unbalance especially when the unbalance occurs between phases. This paper analyzed one novel topology with energy exchange unit (EEU) to realize the phase capacitors voltage balance. After analyzing the converter structure and balance operation concept, this paper provided detailed modulation and capacitors balance control, including maintaining the EEU capacitor voltage stable, sharing the energy storage between phases and in same phase. The simulation results demonstrate the correction of the topology and control.
Renjie Tu,Wenbiao Jin,Song-fang Han,Binbin Ding,Shu-hong Gao,Xu Zhou,Shao-feng Li,Xiaochi Feng,Qing Wang,Qinhui Yang,Yu Yuwen 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5
Linear alkylbenzene sulfonate (LAS), which is widely used as detergent, is a common toxic pollutant in wastewater. Generally, biodegradation process is applied to remove LAS. However, the efficiency of traditional wastewater treatment cannot meet the growing demand. In this study, an improved biological turntable with a symbiotic system of bacteria and microalgae was primarily used to enhance the biodegradation efficiency of LAS from wastewater. The symbiotic system of bacteria and microalgae was mainly composed of Scenedesmus dimorphus and three LAS-degrading bacteria Plesiomonas sp. (L3, L7) and Pseudomonas sp. (H6). The average removal rate of LAS was up to 94.6%. The LAS concentration of the effluent of the system decreased by 81.7% after the bacterial-microalgae inoculation (the inoculation temperature was 25 oC; microalgae were inoculated at a concentration of 10% only at the start of the system; bacteria were continuously inoculated at 1‰ concentration). After bacterial-microalgae inoculation, the average effluent concentration of CODCr in the tertiary reaction tank was 24.3mg/L, the average membrane effluent concentration was 15.8mg/L, and the average removal rate was 90.5%. Compared with the control group without inoculation, the concentration of CODCr in the tertiary reaction tank and membrane effluent decreased by 55.7% and 46.4%. The denaturing gradient electrophoresis (DGGE) pattern analysis of the systemic flora showed that there were two dominant species of high LAS degrading bacteria. They were identified to belong to Plesiomonas sp. and Pseudomonas sp., respectively.
Chlorogenic acid accumulation and related gene expression in peach fruit
Yan Juan,Su Ziwen,Guo Shaolei,Zhang Minghao,Zhang Binbin,Cai Zhixiang,Shen Zhijun,Ma Ruijuan,Yu Mingliang 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.3
To reveal the molecular mechanism in the accumulation of chlorogenic acids (CGAs) in peach (Prunus persica) fruit during growth and development, CGA contents in the flesh of the three peach cultivars ‘Ruiguang 18’, ‘Heiyoutao’, and ‘Beijingyixianhong’ were determined. The expression levels of CGA metabolism-related genes were analyzed based on transcriptome data (RNA-seq). These candidate genes were then screened and real-time fluorescent quantitative PCR (qRT-PCR) was performed to verify their expression. The results showed that the content of total CGAs, 5-O-caffeoylquinic acid and 3-O-caffeoylquinic acid, in the flesh of ‘Ruiguang 18’ exhibited a decreasing trend during fruit development, and there was a great drop at maturity stage (P < 0.05). The three contents in ‘Heiyoutao’ increased first at stage S2 (P < 0.05) and then decreased significantly (P < 0.05). In ‘Beijingyixianhong’, they stayed stable in the early stages, then total CGAs and 3-O-caffeoylquinic acid decreased significantly at the maturity stage (P < 0.05). RNA-seq transcriptome data analysis and qRT-PCR expression analysis showed that the accumulation of CGAs in fruit flesh was mainly affected by the expression of Prupe.3G100800 (PpHCT) and Prupe.3G107300 (Pp4CL), and their expression levels were highly consistent with total CGA content. Thus, we concluded that Prupe.3G100800 (PpHCT) and Prupe.3G107300 (Pp4CL) are the key genes for CGAs synthesis in peach flesh.