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Management of the energy harvesting for MEMS/NEMS via newmark current method
Shang, Kun,Shan, Huafeng,Alkhalaf, Salem,Marzouki, Riadh,Khadimallah, Mohamed Amine Techno-Press 2022 Advances in nano research Vol.12 No.6
The free and forced vibration in addition to electric energy harvesting of a piezoelectric disk resting on two-parameter foundation modeled by modified couple stress as well as Kirchhoff plate theory is probed. The governing equations and boundary conditions are obtained using Hamilton's principle. Then, the free and forced vibration are solved using numerical solutions, generalized differential quadrature method (GDQM) and Newmark-beta method. The forced vibration is resulted from a base excitation load. Also, the possible voltage which can be harvested from this system is obtained using generalized integral quadrature method. The validity of the formulation and solution procedure is confirmed using a compassion study. The impact of parameters such as length effect, inner to outer radius ratio, and foundations parameters on the free and forced vibration as well as energy harvesting is investigated in detail. This paper can be a basis for future studies in the area of piezoelectric harvesters in small scales.
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Adaptive Backstepping Based Fault-tolerant Control for High-speed Trains with Actuator Faults
Shangkun Liu,Bin Jiang,Zehui Mao,Steven X. Ding 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.6
In this paper, the fault-tolerant control problem is addressed for high-speed trains with unknown time varying system parameters, traction system actuator faults and disturbances. To represent the unknown time-varying system parameters in mathematical form, a new piecewise time-varying indicator including commonly used 0-1 case, is employed, which results in a piecewise time-varying nonlinear model with some unknown parameters and piecewise disturbances. For the healthy system with the time-varying indicator in the unknown forms and having known switching time instants, an adaptive backstepping controller is proposed to deal with the unknown system parameters and disturbances and achieve the position tracking. Further, the adaptive backstepping based faulttolerant controller with adaptive laws is developed to guarantee the system states boundedness and the position tracking, in the presence of unknown actuator faults. Based on Lyapunov function, the stability of the closed-loop system is proved. Simulation studies on CRH2 (China Railway High-speed Train II) verify the performance of the proposed fault-tolerant control scheme.
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Spectrum Sensing for Cognitive Radio based on RVM
( Shi Shangkun ),( Jiao Yan ),( Inwhee Joe ) 한국정보처리학회 2019 한국정보처리학회 학술대회논문집 Vol.26 No.1
In a complex geographical environment, communication quality of communication equipment is being seriously challenged. Secondary Users(SUs) must make the best possible use the idle spectrums that Primary Users(PUs) do not use and change spectrum frequently. Using the relevance vector machine(RVM) to establish a signal noise Ratio(SNR) Model for interference information and bit error rate(BER). Through the model and real-time interference information, the minimum channel SNR meeting the BER requirements of communication equipment can be predicted, and we can also calculate the minimum transmitted power. According to the simulation results, this method has better performance interference for selecting available channel and restraining interference.
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3-D axisymmetric subsonic flows with nonzero swirl for the compressible Euler–Poisson system
Bae, Myoungjean,Weng, Shangkun Elsevier 2018 Annales de l'Institut Henri Poincaré. Analyse non Vol.35 No.1
<P><B>Abstract</B></P> <P>We address the structural stability of 3-D axisymmetric subsonic flows with nonzero swirl for the steady compressible Euler–Poisson system in a cylinder supplemented with non-small boundary data. A special Helmholtz decomposition of the velocity field is introduced for 3-D axisymmetric flow with a nonzero swirl (= angular momentum density) component. With the newly introduced decomposition, a quasilinear elliptic system of second order is derived from the elliptic modes in Euler–Poisson system for subsonic flows. Due to the nonzero swirl, the main difficulties lie in the solvability of a singular elliptic equation which concerns the angular component of the vorticity in its cylindrical representation, and in analysis of streamlines near the axis r = 0 .</P>
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Application of KF/MgO as a heterogeneous catalyst in the production of biodiesel from rapeseed oil
Yunbai Luo,Tao Wan,Shangkun Gong,Qiang Li,Ping Yu 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.5
Biodiesel was synthesized from rapeseed oil by transesterification over Magnesium oxide loaded with KF. The catalytic activity strongly depends on the loading amount of KF and calcined temperature. We found that the reaction reached a 79.37% yield when the loading amount was at 35 wt% and calcined at 500 oC. The simply dried 30% KF/MgO at 80 oC was found to give equally good results from the catalyst calcined at 500 oC, avoiding the usual activation at high temperature. The catalysts were characterized by the Hammett indicator method, BET, TG/DTG, XRD, NMR, EDS, and FT-IR. According to the instrumental analysis, the activity in the transesterification probably belonged to coordinately unsaturated F− and liberation of hydroxide during preparation. The effects of methanol/oil ratio and catalyst amounts on the conversion were also studied in this paper.
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Inhibition of Dll4/Notch1 pathway promotes angiogenesis of Masquelet’s induced membrane in rats
Qian Tang,Haimin Jin,Minji Tong,Gang Zheng,Zhongjie Xie,Shangkun Tang,Jialei Jin,Ping Shang,Huazi Xu,Liyan Shen,Yu Zhang,Haixiao Liu 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-
The Masquelet’s induced membrane technique for repairing bone defects has been demonstrated to be a promising treatment strategy. Previous studies have shown that the vessel density of induced membrane is decreased in the late stage of membrane formation, which consequently disrupts the bone healing process. However, relatively little is known about certain mechanisms of vessel degeneration in the induced membrane tissue and whether promotion of angiogenesis in induced membranes can improve bone regeneration. Here, we showed that the Delta-like ligand 4/ Notch homolog 1 (Dll4/Notch1) pathway was relatively activated in the late stage of induced membrane, especially at the subcutaneous site. Then, DAPT, a classical γ-secretase inhibitor, was applied to specifically inhibit Notch1 activation, followed by up-regulation of vascular endothelial growth factor receptor 2 (VEGFR2) and CD31 expression. DAPTmodified induced membranes were further confirmed to contribute to bone regeneration after autogenous bone grafting. Finally, in vitro experiments revealed that knocking down Notch1 contributed to the functional improvement of endothelial progenitor cells (EPCs) and that DAPT-treated induced membrane tissue was more favorable for angiogenesis of EPCs compared with the vehicle group. In conclusion, the present findings demonstrate that Dll4/ Notch1 signaling is negatively associated with the vessel density of induced membrane. Pharmacological inhibition of Notch1 attenuated the vessel degeneration of induced membrane both in vitro and in vivo, which consequently improved bone formation at the bone defect site and graft resorption at the subcutaneous site.
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