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Effect of Earthquake Motion on The Permanent Displacement of Embankment Slope
이진선,Qihang Liu,박헌준 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.10
Permanent displacement of slopes is key data for designing the slope in performance-based seismic design. To estimate the permanent displacement of a slope, empirical as well as numerical methods should be adopted. However, the results of these methods are highly dependent on both stationary and nonstationary ground-motion characteristics. This paper aims to find the most influential nonstationary characteristics of earthquakes on the permanent displacement of slopes. Two different numerical methods, Newmark’s sliding-block and response-history analysis, are used for a total of 47 real earthquake records. The records are classified into three groups based on their event characteristics. They are spectrally matched before analysis to the target spectrum to eliminate the effect of stationary characteristics. The amount of permanent displacement obtained from the analyses is different for varying input motions. The intensity-based parameters, destructiveness potential factor, Arias intensity, and characteristic intensity play an important role on the permanent displacement of the slope. The results of this study are expected to yield judgment criteria for designers to select appropriate ground motion to evaluate the permanent displacement of slopes under seismic loading.
Tariku Sinshaw Tamir,Qihang Fang,Ehtisham Lodhi,Gang Xiong,Zhen Shen,Xisong Dong,Sheng Liu,Fei-Yue Wang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3
Additive manufacturing, also known as 3D printing, is an emerging technology. The existing additive manufacturing technologies deploy a 3-axis printing mechanism where the material accumulation grows only in the z-direction. This results in limited printing freedom. Apart from this, support structures are needed to print overhang structures. Removal of these supports ultimately reduces print quality. This paper proposes a novel robotassisted additive manufacturing along with a control system framework, which possesses multi-directional printing without support structures. Taking the advantage of its high stiffness and high payload-to-weight ratio, a 6-degree of freedom Stewart platform manipulator is designed to substitute the printer build plate. The kinematics and dynamics of the manipulator is formulated. Then, an extended proportion-derivation sliding mode controller is designed for trajectory tracking. The modified grey wolf optimization algorithm is applied to compute the optimal controller parameters. The integral absolute error (IAE) is used as a cost function and its minimum value is reached in the iteration interval [75,100]. The analytical model simulation in MATLAB is run for 10 seconds, and the results show that the desired length trajectories of the six legs of the manipulator are achieved after 3.5 seconds. The performance of the analytical model is verified on the automated dynamic analysis of mechanical systems (ADAMS).
HALF-METALLIC SILICENE AND GERMANENE NANORIBBONS: TOWARDS HIGH-PERFORMANCE SPINTRONICS DEVICE
YANGYANG WANG,JIAXIN ZHENG,ZEYUAN NI,RUIXIANG FEI,QIHANG LIU,RUGE QUHE,CHENGYONG XU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2012 NANO Vol.7 No.5
By using first-principles calculations, we predict that an in-plane homogenous electrical ¯eld can induce half-metallicity in hydrogen-terminated zigzag silicene and germanene nanoribbons (ZSiNRs and ZGeNRs). A dual-gated ¯nite ZSiNR device reveals a nearly perfect spin-¯lter e±ciency (SFE)of up to 99% while a quadruple-gated ¯nite ZSiNR device serves as an effective spin ¯eld e®ect transistor (FET) with an on/o® current ratio of over 100 from ab initio quantum transport simulation. This discovery opens up novel prospect of silicene and germanene in spintronics.
Deng Qihuang,Zhou Junquan,Li Xianping,Feng Yefeng,Liang Yurun,Liu Qihang 한국물리학회 2021 Current Applied Physics Vol.22 No.-
Polymer/conductive ceramic composites with high dielectric constant have become research hotspot of dielectric capacitor materials. However, the conductivity and dielectric loss increase when high dielectric constant is achieved. In order to reconcile high dielectric constant and low dielectric loss, in this study, poly (vinylidene fluoride) (PVDF)/chromium carbide (Cr2C3)/montmorillonite (MMT) ternary composite films were prepared by solution cast. Dielectric response based on interfacial polarization was improved and dielectric constant of composites was increased. MMT ceramic was used to suppress interface leakage current. Compared with PVDF/ Cr2C3 composites, the conductivity and dielectric loss of ternary composites were reduced.