Deeams for the Futures

Cheng Xin 한국콘텐츠학회 2022 ICCC International Digital Design Invitation Exhib Vol.2022 No.07

Study on Ultimate Capacity of Steel H-Section Members Under Combined Biaxial Bending and Axial Force

Cheng Xin,Wang Xiaxin,Zhang Chao,Duan Dexin 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5

The ultimate resistance of steel H-section members under biaxial bending and compression has been discussed in the present paper. Finite element models taking account of geometrical and material nonlinearities are established and validated by previous laboratory test results. A series of parametric studies are then conducted considering diff erent loading angles and a spectrum of fl ange width-to-thickness ratios, web width-to-thickness ratios and axial force ratios. An improved energy infl ection method (EIM), which is verifi ed by comparing the analytical results with numerical results, is proposed in order to determine the ultimate state of the members under biaxial bending. It is shown that the ultimate state determined by EIM occurs when the sectional stress distribution reaches the envelop line. Finally, a simple interaction formula is proposed to predict the ultimate capacity of the steel H-section columns subjected to biaxial bending and compression. It is verifi ed that the interaction formula can provide a satisfactory prediction, in comparison against the European code which tends to off er a relatively conservative estimate. The proposed method is applicable to fl ange width-to-thickness ratios ranging from 8 to 28, web width-to-thickness ratios changing from 30 to 120, and axial force ratios varying from 0 to 0.4.

Extraordinary Optical Transmission and Enhanced Magneto-optical Faraday Effect in the Cascaded Double-fishnet Structure with Periodic Rectangular Apertures

Chengxin Lei,Zhongsheng Man,Shaolong Tang 한국광학회 2020 Current Optics and Photonics Vol.4 No.2

A significant enhancement of the magneto-optical Faraday rotation and extraordinary optical transmission (EOT) in the cascaded double-fishnet (CDF) structure with periodic rectangular apertures is theoretically predicted by using the extended finite difference time domain (FDTD) method. The results demonstrate that the transmittance spectrum of the CDF structure has two EOT resonant peaks in a broad spectrum spanning visible to near-infrared wavebands, one of them coinciding with the enhanced Faraday rotation and large figure of merit (FOM) at the same wavelength. It is most important that the resonant position and intensity of the transmittance, Faraday rotation and FOM can be simply tailored by adjusting the incident wavelength, the thickness of the magnetic layer, and the offset between two metallic rectangular apertures, etc. Furthermore, the intrinsic physical mechanism of the resonance characteristics of the transmittance and Faraday rotation is thoroughly studied by investigating the electromagnetic field distributions at the location of resonance. It is shown that the transmittance resonance is mainly determined by different hybrid modes of surface plasmons (SPs) and plasmonic electromagnetically induced transparency (EIT) behavior, and the enhancement of Faraday rotation is mostly governed by the plasmonic electromagnetically induced absorption (EIA) behavior and the conversion of the transverse magnetic (TM) mode and transverse electric (TE) mode in the magnetic dielectric layer.

Rethinking Chinese Power: A Conceptual Corrective to the “Power Shift” Narrative

Chengxin Pan 경남대학교 극동문제연구소 2014 ASIAN PERSPECTIVE Vol.38 No.3

A growing body of literature has focused on an alleged “power shift” from the United States to China (and from the West to the East more generally). For all its complexities and nuances, much of this “power-shift” literature continues to unreflectively hold onto a conventional way of conceptualizing power as a type of quantitatively measurable and zero-sum property possessed by the state. Without critically engaging with the conceptual question of what power means, however, the “power-shift” debate is both inadequate and misleading. Drawing on some alternative ways of conceptualizing power, this article aims to illustrate the contingent and socially constructed nature of “Chinese” (economic) power and, in doing so, problematize the widely held view of a US-China power shift. It contends that insofar as power is socially constructed, how it is conceptualized matters for international relations. The need to rethink power is at the core of building a new type of major power relationship.

Indefinite stochastic LQ control with cross term via semidefinite programming

Chengxin Luo,Enmin Feng 한국전산응용수학회 2003 Journal of applied mathematics & informatics Vol.13 No.1-2

Indefinite stochastic optimal LQR control with cross term under IQ constraints

Chengxin Luo,Enmin Feng 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.15 No.-

A stochastic optimal LQR control problem under some integralquadratic (IQconstraints is studied, with cross terms in both the cost andthe constraint functionals, allowing all the control weighting matrices beingindenite. Sucient conditions for the well-posedness of this problem aregiven. When these conditions are satised, the optimal control is explicitlyderived via dual theory.

INDEFINITE STOCHASTIC LQ CONTROL WITH CROSS TERM VIA SEMIDEFINITE PROGRAMMING

Luo, Chengxin,Feng, Enmin 한국전산응용수학회 2003 Journal of applied mathematics & informatics Vol.13 No.1

An indefinite stochastic linear-quadratic(LQ) optimal control problem with cross term over an infinite time horizon is studied, allowing the weighting matrices to be indefinite. A systematic approach to the problem based on semidefinite programming (SDP) and .elated duality analysis is developed. Several implication relations among the SDP complementary duality, the existence of the solution to the generalized Riccati equation and the optimality of LQ problem are discussed. Based on these relations, a numerical procedure that provides a thorough treatment of the LQ problem via primal-dual SDP is given: it identifies a stabilizing optimal feedback control or determines the problem has no optimal solution. An example is provided to illustrate the results obtained.

Predictive simulation for the design of robotic solution to mobility aid

Yin ChengXin,Benali Abderraouf,Kratz Frédéric 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.6

Maintaining substantial mobility is essential for those who suffer from reduced mobility to regain their independence in daily motion tasks. In recent years, robotic solutions to human mobility aid have been functionally verified by various applications. Moreover, with the emergence of new robots and systems, the robot design theory is also under rapid evolution. This paper proposes a methodology to enhance the design of robotic exoskeleton. The aim was to help the designer to select adequate dynamical behaviors to the development of control scheme for the human motions assisted by a robotic assistance device. The main contribution of this work resides in the proposition of optimized impedance parameters for a particular human movement via neuromusculoskeletal (NMS) modelization and predictive simulation. The technique of NMS modeling that represents the motions of human upper limb was applied to study the underlying mechanisms of human movements. Predictive simulation integrated with the NMS model was formulated and solved for generating a series of optimized human dynamic parameters. In this paper, a case study of human–robot interface has been proposed to exemplify our methodology. The modeling and simulation processes were validated with experimental tools. According to the simulated human dynamics, the optimized stiffness and damping coefficients of one degree of freedom were calculated. Results show that our methods are promising and allowed to specify the human movement for a given task, and can provide the design parameters to control scheme of a robotic exoskeleton.

Insight on photocatalytic oxidation of high concentration NO over BiOCl/ Bi2WO6 under visible light

Wanyuan Wang,Chengxin Wen,Jing Guan,Hengxiao Man,Junjie Bian 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

The exhaust gas from an SCR (Selective Catalytic Reduction) unit still has about 100 ppm NO. BiOX/Bi2WO6 catalysts were fabricated by a one-step ultrasound-assisted method and employed for photocatalyticoxidation of NO under visible light. The bandgap energy of BiOX (Cl, Br, I)/Bi2WO6 were estimatedto be 2.65 eV, 2.35 eV, and 1.75 eV, respectively. Photocurrent density and EIS curves revealed that BiOCl/Bi2WO6 had the optimal charge transfer velocity. Simulated NO removal experiments of BiOX/Bi2WO6catalysts were carried out in a fixed bed reactor, 20–30% NO (100 ppm inlet) removal rate was achievedunder visible light while promoting by H2O vapor, and the maximum NO removal rate is up to 31% onBiOCl/Bi2WO6. The fitted L-H model revealed that NO oxidation followed two-centered adsorption, andscavenger experiments confirm that the main ROS (Reactive Oxygen Species) was OH. In situ DRIFT spectrarevealed that there were bridging nitrates, monodentate and bridging nitrites, and other intermediatesformed on the BiOCl/Bi2WO6, these species can be scrubbed by seawater to regenerate thecatalyst. The NO photocatalytic oxidation pathway was proposed. Good activity and stability of BiOCl/Bi2WO6 provide a new approach for scale-up application of NO oxidation under visible light.

The effective mechanism of the polysaccharides from Panax ginseng on chronic fatigue syndrome

Jia Wang,Chengxin Sun,Yan Zheng,Hongling Pan,Yifa Zhou,Yuying Fan 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.4

Ginseng acidic polysaccharide WGPA isolatedfrom the root of Panax ginseng C. A. Meyer was fractionatedinto WGPA-A and WGPA-N by anion-exchangechromatography. The antifatigue activity of ginseng acidicpolysaccharide WGPA has been reported in our previousresearch. This present study was designed to identify itsactive component and elucidate the mechanism for preventingchronic fatigue syndrome (CFS). WGPA, WGPAAand WGPA-N were orally administered to mice oncedaily for 15 days. The effects of these compounds onphysiological biomarkers of oxidative stress and on themorphology of the mitochondria in striated skeletal musclewere assessed. The results of forced swimming testinducedindicated that WGPA and WGPA-A couldlengthen the swimming time, while WGPA-N could not. Inaddition, malondialdehyde and lactate dehydrogenase levelsin serum were enhanced; while those of superoxidedismutase and glutathione peroxidase were lowered. Interestingly, the structural degeneration of mitochondriawere all ameliorated. These findings suggested thatWGPA-A is the active component of WGPA, it might havepotential therapeutic effects for CFS and the oxidative stress might be involved in the pathogenesis. Our resultsalso provided essential data for a better understanding ofthe antifatigue effects of P. ginseng extracts.