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Yaohua Li,Jikang Fan,Yang Liu,Xiaoyu Wang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.5
According to the position relationship between the vehicle and the obstacle, a new obstacle avoidance path planner was designed to solve the limitation of traditional local obstacle avoidance path planner in excessive obstacle avoidance. In order to improve the control accuracy of the path tracking controller and ensure the stability of the vehicle, a comprehensive evaluation index of path tracking performance considering control accuracy and driving stability was established. The optimal prediction time domain and control time domain parameters at different vehicle speeds were obtained, and an adaptive dual time domain parameter path tracking controller was designed. Based on the joint-simulation platform, the integrated structure of the planning layer and the control layer was simulated and verified. Simulation results show that the new obstacle avoidance function can avoid excessive obstacle avoidance while ensuring real-time performance, and improve the driving stability of the vehicle. The adaptive time-domain parameter path tracking controller has better comprehensive control performance and can improve driving safety under extreme conditions. The integrated structure of local obstacle avoidance path planning and path tracking control are beneficial for the vehicle to plan and accurately track the local obstacle avoidance path in multiple static obstacle scenes.
Ren Meibin,Wang Yifan,Liu Guoxin,Zuo Bin,Zhang Yuancheng,Wang Yunhe,Liu Weifeng,Liu Xiangmei,Zhong Yaohua 한국미생물학회 2020 The journal of microbiology Vol.58 No.8
The saprophytic fungus Trichoderma reesei has long been used as a model to study microbial degradation of lignocellulosic biomass. The major cellulolytic enzymes of T. reesei are the cellobiohydrolases CBH1 and CBH2, which constitute more than 70% of total proteins secreted by the fungus. However, their physiological functions and effects on enzymatic hydrolysis of cellulose substrates are not sufficiently elucidated. Here, the cellobiohydrolase-encoding genes cbh1 and cbh2 were deleted, individually or combinatively, by using an auxotrophic marker-recycling technique in T. reesei. When cultured on media with different soluble carbon sources, all three deletion strains (Δcbh1, Δcbh2, and Δcbh1Δcbh2) exhibited no dramatic variation in morphological phenotypes, but their growth rates increased apparently when cultured on soluble cellulase-inducing carbon sources. In addition, Δcbh1 showed dramatically reduced growth and Δcbh1Δcbh2 could hardly grew on microcrystalline cellulose (MCC), whereas all strains grew equally on sodium carboxymethyl cellulose (CMC-Na), suggesting that the influence of the CBHs on growth was carbon source-dependent. Moreover, five representative cellulose substrates were used to analyse the influence of the absence of CBHs on saccharification efficiency. CBH1 deficiency significantly affected the enzymatic hydrolysis rates of various cellulose substrates, where acid pre-treated corn stover (PCS) was influenced the least. CBH2 deficiency reduced the hydrolysis of MCC, PCS, and acid pre-treated and delignified corncob but improved the hydrolysis ability of filter paper. These results demonstrate the specific contributions of CBHs to the hydrolysis of different types of biomass, which could facilitate the development of tailor-made strains with highly efficient hydrolysis enzymes for certain biomass types in the biofuel industry.
Rana Naveed Ur Rehman,Yaohua You,Sajid Ali,Yule Wang,Lei Zhang,Pengmin Li,Fengwang Ma 한국원예학회 2018 Horticulture, Environment, and Biotechnology Vol.59 No.1
Polyphenol intermediates accumulate predominantly in peripheral parts of floral tissues and play various roles in tissuehomeostasis. A limited ornamental flower shelf life is caused by early tissue senescence, otherwise known as programmedcell death (PCD), which is characterized by processes such as DNA degradation, reduction in protein content and others. However, the role of polyphenols during PCD is poorly understood. In this study, we evaluated polyphenols as potentialbiochemical markers during developmental changes associated with PCD. Malus crabapple flowers were exposed to low(LT = 13 ± 2 °C), room (RT = 23 ± 2 °C), and high (HT = 30 ± 2 °C) temperatures to induce different levels of PCD. HTtreatment was associated with enhanced H2O2and MDA content, which subsequently caused lower protein concentrationand induced DNA degradation. Conversely, substantially higher protein content, lesser DNA degradation, and lower H2O2and MDA accumulation were observed following RT and LT treatments. Furthermore, significantly higher concentrationsof phenolic acids, flavanols, and anthocyanins were observed following both RT and LT treatments, more so for the latter,due to up-regulation of structural genes such as MpPAL, MpDFR, MpLDOX, and MpUFGT. Similarly, following HT treatmentthat induced a higher rate of PCD, the accumulation of dihydrochalcone and flavonols was significantly enhanced andassociated with increased expression of MpCHS and MpFLS. Phenolic contents are determined via precise regulation of ahighly conserved set of structural genes, indicating their functional importance. Therefore, it was assumed that individualphenolic intermediates or discrete diverse classes of polyphenol compounds may be utilized as biochemical markers of PCDin woody ornamental flowers of Malus crabapple.
The Development of IGCT-based Large Capacity Three-Level Dual-PWM Converter
Lan Zhiming,Li Chongjian,Li Yaohua,Zhu Chunyi,Wang Chengsheng 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5
In media and high voltage large capacity converter systems the Integrated Gate Commutated Thyristor (IGCT) take the place of Gate Turn Off Thyristor (GTO) duo to its outstanding performance. And IGCT-based large capacity three-level converters are widely used in industrial motor-driving field. In this paper the development of a set of IGCT-based large capacity three-level dual-PWM converter is introduced. The converter includes PWM rectifier, DC capacitors, PWM inverter. The topology of the converter is given. The close-loop control strategy and SVPWM algorithm of PWM rectifier is presented in this paper. The control strategy and algorithm of the PWM inverter is also presented. The experiments were performed and the results show that the converter reaches the design requirement and has excellent performance.