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Liu, Weipeng,Cui, Xiaofeng,Zhou, Jiyao,Zhang, Zehua,Hou, Mingxuan,Shan, Shengqi,Wu, Shang The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11
In this paper, a composite passivity-based control method based on a finite-time disturbance observer (FTDO) and a passivity-based control (PBC) is proposed to improve the stability of the Boost converters with constant power loads in DC Microgrids. The FTDO improves the robustness and rapidity of the system by accurately estimating system disturbances. The PBC ensures the stability of the system via its transient energy dissipation. The FTDO operates parallel to the PBC, and compensates the observed value to the PBC through a feedforward channel. When compared with other controls, the proposed composite passivity-based control has the advantages of a fast dynamic response and accurate tracking of system disturbances in a wide working range. Finally, the control method proposed in this paper is verified by MATLAB/Simulink simulations and hardware in the hard-ware-in-loop experiments.
Residual Stress Distribution in Hard-Facing of Pressure Relief Valve Seat
Ai, Li,Yu, Xinhai,Jiang, Wenchun,Woo, Wanchuck,Ze, Xiaofeng,Tu, Shan-Tung AMERICAN SOCIETY MECHANICAL ENGINEERS 2014 Journal of Pressure Vessel Technology Vol.136 No.6
<P>In this study, for the hard-facing of spring-loaded pressure relief valve seats, the residual stress distributions after the tungsten inert gas welding, (TIG) postwelded heat treatment and subsequent surface turning were investigated. The heat input parameters of welding were calibrated using an infrared imaging and thermocouples. The residual stress distributions were computed using three-dimensional finite element model. The neutron diffraction approach was employed to verify the finite element calculation. It is found that, the surface temperature during hard-facing welding shows a double ellipsoidal shape with the highest value of around 1570 degrees C. The high residual stress zones are located exactly under the welded joint except a slight deviation in the hoop direction. The magnitudes of tensile residual stresses in the three directions increase with their corresponding locations from the root of the joint into the base metal. The residual stresses in all of the three directions decrease significantly after the heat treatment. After surface turning, the residual stresses are tensile except for those close to the inner surface that are compressive in axial and radial directions.</P>
Yihui Yang,Yifan Kang,Yifan Yang,Mengkun Ding,Xiaofeng Shan,Zhigang Cai 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-
Background Implant-supported dentures have become an essential means of restoring occlusal function after jaw reconstruction. Bone mineral density (BMD) may influence the success rate of implant denture restorations. This study aimed to explore whether the Hounsfield unit (HU) value can be used to monitor the changing trend of fibular BMD after jaw reconstruction. Results A total of 54 patients who underwent maxillar/mandibular reconstruction with a fibula flap were included in this study. There was a significant correlation between the HU value and BMD at 1 week, 3 months, and 6 months after surgery, and both were significantly correlated with follow-up time. The difference between each pair of absorption rates (DAR) was less than 10% in 66.7% and 75.9% of patients at 3 and 6 months; however, the DAR was more than 20% in 12% and 13.8% of patients at 3 and 6 months, respectively. Conclusions There is a significant correlation between HU value and BMD. The HU value can be used to roughly reflect the fibular BMD changing trend in a group of patients as opposed to an individual, and the HU value is not equivalent to BMD. Trial registration ChiCTR, ChiCTR2300069661, retrospectively registered on 22 March 2023. Retrospectively registered, https:// www. chictr. org. cn/ showp roj. html? proj= 188953.
Guan Yongchao,Zhang Meng,Wang Yingda,Liu Zhongzhuo,Zhao Zelin,Wang Hong,An Dingjie,Qian Aidong,Kang Yuanhuan,Sun Wuwen,Shan Xiaofeng 한국미생물학회 2022 The journal of microbiology Vol.60 No.12
Aeromonas veronii is a pathogen which can induce diseases in humans, animals and aquatic organisms, but its pathogenic mechanism and virulence factors are still elusive. In this study, we successfully constructed a mutant strain (ΔascP) by homologous recombination. The results showed that the deletion of the ascP gene significantly down-regulated the expression of associated effector proteins in A. veronii compared to its wild type. The adhesive and invasive abilities of ΔascP to EPC cells were 0.82-fold lower in contrast to the wild strain. The toxicity of ΔascP to cells was decreased by about 2.91-fold (1 h) and 1.74-fold (2 h). Furthermore, the LD50 of the mutant strain of crucian carp was reduced by 19.94-fold, and the virulence was considerably attenuated. In contrast to the wild strain, the ΔascP content in the liver and spleen was considerably lower. The titers of serum cytokines (IL-8, TNF-α, and IL-1β) in crucian carp after the infection of the ΔascP strain were considerably lower in contrast to the wild strain. Hence, the ascP gene is essential for the etiopathogenesis of A. veronii TH0426.