A micro-grid smooth transfer control strategy based on a special slave distributed generation unit

Xin Meng,Jinjun Liu,Zeng Liu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper proposes a novel control strategy for a micro-grid to achieve a smooth transition between gridconnected (GC) mode and stand-alone (SA) mode with the help of a special slave distributed generation (DG) unit. In the conventional smooth transfer control methods, only the control strategy of master DG unit is emphasized; and the slave DG unit outputs constant active and reactive power based on PQ control, which is useless for the smooth transition. In the proposed control strategy, the master DG units adopt the traditional hybrid voltage and current control method. When a utility outage occurs, one special slave DG unit is used to compensate the power mismatch between the output power of DG units and the power consumed by the load, which can suppress the drift of load voltage. When the grid returns to a normal state, the pre-synchronization can be achieved by regulating the output power of this special slave DG unit. The simulation results are provided to verify the effectiveness of this control strategy.

Finite-time Synchronization of Variable-order Fractional Uncertain Coupled Systems via Adaptive Sliding Mode Control

Xin Meng,Cunchen Gao,Baoping Jiang,Zhengtian Wu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.5

This paper aims to investigate the problem of adaptive sliding mode control (SMC) for a class of variableorder fractional (VOF) uncertain coupled systems. First, a novel VOF integral-type sliding surface composed of nonlinear coupling terms is designed with the aid of VOF calculus. Second, based on graph theory, novel asymptotical stability criteria are obtained for the obtained sliding mode dynamics. Moreover, the finite-time reachability of the predefined VOF integral-type sliding surface is ensured by designing a novel adaptive VOF controller. Finally, two numerical studies are presented to verify the validity and superiority of the proposed control strategy.

Molybdenum Trioxide Dihydrate-Graphene Composite for Electrochemical Detection of Thiourea Molecule

Xinmeng Zhang,Kezhi Li,Hejun Li,Jinhua Lu,Leilei Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.3

A novel electrochemical sensing platform was constructed based on a facile self-assembly procedure synthetic laminar molybdenum trioxide dihydrate (MoO3 · 2H2O)-graphene composite. Field emission scanning electron microscopy (FESEM), X-ray spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy were employed to characterize the morphology and composition of the MoO3 · 2H2O-graphene composite. As a model molecule, thiourea was utilized to investigate the electrochemical behaviors of the MoO3 · 2H2O-graphene composite modified glass carbon electrode. The results show that the composite modified electrode has higher electron transfer rate than that of graphene modified electrode and bare glass carbon electrode meanwhile the peak currents of it has a good linear relationship with thiourea concentrations in the range of 2.40 X 10-3 − 19.3 X 10-3 M (R = 0.998) with detection limit of 4.99 µM (S/N = 3). This novel electrochemical sensor exhibits a higher absorption capacity (3.87 X 10-8 mol/cm2 ), a good reproducibility (1.41% relative standard deviation (RSD)), excellent anti-interference and a high stability. These excellent electrochemical properties of the MoO3 · 2H2O-graphene composite are attributed to the loose and porous structure and the synergistic effects between graphene and MoO3 · 2H2O, which make this composite material hold great potential applications for electrochemical sensor.

An incompatible 3D solid element for structural analysis at elevated temperatures

Xinmeng Yu,Xiaoxiong Zha,Zhaohui Huang 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.3

The eight-node 3D solid element is one of the most extensively used elements in computational mechanics. This is due to its simple shape and easy of discretization. However, due to the parasitic shear locking, it should not be used to simulate the behaviour of structural members in bending dominant conditions. Previous researches have indicated that the introduction of incompatible mode into the displacement field of the solid element could significantly reduce the shear locking phenomenon. In this study, an incompatible mode eight-node solid element, which considers both geometric and material nonlinearities, is developed for modelling of structural members at elevated temperatures. An algorithm is developed to extend the state determination procedure at ambient temperature to elevated temperatures overcoming initially converged stress locking when the external load is kept constant. Numerical studies show that this incompatible element is superior in terms of convergence, mesh insensitivity and reducing shear locking. It is also showed that the solid element model developed in this paper can be used to model structural behaviour at both ambient and elevated temperatures.

An incompatible 3D solid element for structural analysis at elevated temperatures

Yu, Xinmeng,Zha, Xiaoxiong,Huang, Zhaohui Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.3

The eight-node 3D solid element is one of the most extensively used elements in computational mechanics. This is due to its simple shape and easy of discretization. However, due to the parasitic shear locking, it should not be used to simulate the behaviour of structural members in bending dominant conditions. Previous researches have indicated that the introduction of incompatible mode into the displacement field of the solid element could significantly reduce the shear locking phenomenon. In this study, an incompatible mode eight-node solid element, which considers both geometric and material nonlinearities, is developed for modelling of structural members at elevated temperatures. An algorithm is developed to extend the state determination procedure at ambient temperature to elevated temperatures overcoming initially converged stress locking when the external load is kept constant. Numerical studies show that this incompatible element is superior in terms of convergence, mesh insensitivity and reducing shear locking. It is also showed that the solid element model developed in this paper can be used to model structural behaviour at both ambient and elevated temperatures.

The structural performance of axially loaded CFST columns under various loading conditions

Fuyun Huang,Xinmeng Yu,Baochun Chen 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.5

Concrete filled steel tube (CFST) structures have been used widely in high-rise buildings and bridges due to the efficiency of structurally favourable interaction between the steel tube and the concrete core. In the current design codes only one loading condition in the column members is considered, i.e., the load is applied on the steel tube and concrete core at the same time. However, in engineering practice the tube structures may be subjected to various loading conditions such as loading on the concrete core only, preloading on the steel tube skeleton before filling of concrete core, and so on. In this research, a series of comparative experiments were carried out to study the structural performance of concrete filled circular steel tube columns subject to four concentric loading schemes. Then, a generalized prediction method is developed to evaluate the ultimate load capacity of CFST columns subject to various loading conditions. It is shown that the predictions by the proposed method agree well with test results.

Multiple Feature Voting based Human Interaction Recognition

Xiaofei Ji,Changhui Wang,Xinmeng Zuo,Yangyang Wang 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1

3',4',5',5,7-Pentamethoxyflavone Sensitizes Cisplatin-Resistant A549 Cells to Cisplatin by Inhibition of Nrf2 Pathway

Xiangyu Hou,Xupeng Bai,Xiaoli Gou,Hang Zeng,Chen Xia,Wei Zhuang,Xinmeng Chen,Zhongxiang Zhao,Min Huang,Jing Jin 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.5

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important redox-sensitive transcription factor that regulates the expression of several cytoprotective genes. More recently, genetic analyses of human tumors have indicated that Nrf2 may cause resistance to chemotherapy. In this study, we found that the expression levels of Nrf2 and its target genes GCLC, HO-1, NQO1 were significantly higher in cisplatinresistant A549 (A549/CDDP) cells than those in A549 cells, and this resistance was partially reversed by Nrf2 siRNA. 3',4',5',5,7-Pentamethoxyflavone (PMF), a natural flavonoid extracted from Rutaceae plants, sensitized A549/CDDP to CDDP and substantially induced apoptosis compared with that of CDDP alone treated group, and this reversal effect decreased when Nrf2 was downregulated by siRNA. Mechanistically, PMF reduced Nrf2 expression leading to a reduction of Nrf2 downstream genes, and in contrast, this effect was decreased by blocking Nrf2 with siRNA. Taken together, these results demonstrated that PMF could be used as an effective adjuvant sensitizer to increase the efficacy of chemotherapeutic drugs by downregulating Nrf2 signaling pathway.

3',4',5',5,7-Pentamethoxyflavone Sensitizes Cisplatin-Resistant A549 Cells to Cisplatin by Inhibition of Nrf2 Pathway

Hou, Xiangyu,Bai, Xupeng,Gou, Xiaoli,Zeng, Hang,Xia, Chen,Zhuang, Wei,Chen, Xinmeng,Zhao, Zhongxiang,Huang, Min,Jin, Jing Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.5

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important redox-sensitive transcription factor that regulates the expression of several cytoprotective genes. More recently, genetic analyses of human tumors have indicated that Nrf2 may cause resistance to chemotherapy. In this study, we found that the expression levels of Nrf2 and its target genes GCLC, HO-1, NQO1 were significantly higher in cisplatin-resistant A549 (A549/CDDP) cells than those in A549 cells, and this resistance was partially reversed by Nrf2 siRNA. 3,4,5,5,7-Pentamethoxyflavone (PMF), a natural flavon extracted from Rutaceae plants, sensitized A549/CDDP to CDDP and substantially induced apoptosis compared with that of CDDP alone treated group, and this reversal effect decreased when Nrf2 was downregulated by siRNA. Mechanistically, PMF reduced Nrf2 expression leading to a reduction of Nrf2 downstream genes, and in contrast, this effect was decreased by blocking Nrf2 with siRNA. Taken together, these results demonstrated that PMF could be used as an effective adjuvant sensitizer to increase the efficacy of chemotherapeutic drugs by downregulating Nrf2 signaling pathway.