Postbuckling and nonlinear vibration of composite laminated trapezoidal plates

Guoqing Jiang,Fengming Li,Chuanzeng Zhang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.1

The thermal effects on the buckling, postbuckling and nonlinear vibration behaviors of composite laminated trapezoidal plates are studied. Aiming at the complex plate structure and to simulate the temperature distribution of the plate, a finite element method (FEM) is applied in this paper. In the temperature model, based on the thermal diffusion equation, the Galerkin’s method is employed to establish the temperature equation of the composite laminated trapezoidal plate. The geometrical nonlinearity of the plate is considered by using the von Karman large deformation theory, and combining the thermal model and aeroelastic model, Hamilton’s principle is employed to establish the thermoelastic equation of motion of the composite laminated trapezoidal plate. The thermal buckling and postbuckling of the composite laminated rectangular plate are analyzed to verify the validity and correctness of the present methodology by comparing with the results reported in the literature. Moreover, the effects of the temperature with the ply-angle on the thermal buckling and postbuckling of the composite laminated trapezoidal plates are studied, the thermal effects on the nonlinear vibration behaviors of the composite laminated trapezoidal plates are discussed, and the frequency-response curves are also presented for the different temperatures and ply angles.

Symplectic Elasticity Analysis of Stress in Surrounding Rock of Elliptical Tunnel

Zhongyu Jiang,Guoqing Zhou,Li Jiang 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.10

A large number of non-circular tunnels are widely used in engineering practice. The application of these geometric structures not only makes the boundary conditions of mechanical problems more complex, but also makes the theoretical solution more difficult. The introduction of curvilinear coordinate system can easily transform the elliptical region into a circular region, and the physical relationship can also be adjusted accordingly. In the state space, the transformed problem can be solved by using the dual variables of Hamiltonian mechanics, and the special solution equation can be obtained. With regard to the non-homogeneous boundary conditions of general engineering problems, Fourier expansion is used to transform them into algebraic sums. According to the special solution equation, the relationship between the direction eigenvalues and the angle coefficients of each order of the expansion term is found. Then the analytical solution of the non-homogeneous problem is obtained by superposing the special solutions of the expansion terms of each order. By comparing the calculation results of the boundary stress around the elliptical tunnel, it can be seen that the results are completely consistent with the finite element calculation results, which verifies the correctness and reliability of the method in this paper. This paper analyzes the influence of internal pressure, lateral pressure coefficient and elliptical shape coefficient on the circumferential stress around the elliptical hole, and obtains the following conclusions: increasing the internal pressure of the elliptical hole can effectively reduce the circumferential compressive stress at the hole edge; when the lateral pressure coefficient approaches 1, the circumferential stress distribution around the elliptical hole tends to be uniform; the minimum value of the circumferential stress around the elliptical hole is independent of the shape coefficient, while the maximum value is closely related to the shape coefficient. The research results can not only provide specific theoretical guidance for the construction and construction of elliptical tunnel, but also expand the application scope of the symplectic elasticity method.

Effect of Temperature and Strain Rate on the Hot Deformation Behaviour of Ferritic Stainless Steel

Guoqing Zu,Yukuan Lu,Yi Yan,Xiaoming Zhang,Jingwei Zhao,Wei Du,Xu Ran,Zhengyi Jiang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2

The fow behaviour and microstructure characteristics of a ferritic stainless steel were investigated using plain strain compression test on a Gleeble 3500 thermo-mechanical test simulator with a hydrawedge system in the temperature range of850–1100 °C and strain rate range of 0.1–50 s−1. The phenomenological constitutive model and the relationship betweenthe Zener–Hollomon (Z) parameter and fow stress were established. The results reveal that the fow softening phenomenonoccurs at high strain rate, which is caused by the coupling efect of the adiabatic heating and dynamic recrystallisation (DRX). New grains nucleate preferentially at the original grain boundaries by strain-induced grain boundary migration. With anincrease of temperature or strain rate, a part of new grains form in the interior of deformed grains. The DRX grain size andfraction increase with the increase of temperature, however, exhibit a non-linear relationship with strain rate.

Enhanced Field Emission from UV-Illuminated CuO Nanowires Fabricated by Thermal Oxidation of Cu Film

Jiang Zhao,Debo Wang,Yue Chen,Qiu Jin,Guoqing Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.5

Cupric Oxide (CuO) nanowires have been successfully synthesized by direct thermal oxidation of Cu film in air. The morphologies and structures of the synthesized materials are investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results imply that CuO nanowires with well vertical arrays present very narrow sharp peaks, indicating the nanowires are highly crystalline. The effect of ultraviolet (UV) illumination on the field emission characteristics of the CuO nanowires is investigated. The turn-on electric field of UV-illuminated CuO nanowires decreases and the field enhancement factor enhances.

Fabrication of novel self-healable ultraslippery surface for preventing marine microbiologically influenced corrosion

Hao Jiang,Wenhuan Wang,Jiawei Li,Liyang Zhu,Dun Zhang,Peng Wang,Guoqing Wang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

Slippery liquid-infused porous surfaces (SLIPS) have attracted wide attention in the field of marine anticorrosion. However, the stability problem severely restricts the broad applications of SLIPS. Herein, wefabricated a polyurethane-based ultraslippery surface with lubricant self-replenishing and matrix selfhealingproperties owing to the huge amount of dynamic hydrogen-bond. Besides, the bacteria culturetest and electrochemical analysis results indicate the prepared surface possesses superior properties inthe protection of microbiologically influenced corrosion (MIC). This paper offers an efficient strategy tosolve stability problem of SLIPS, and the as-obtained self-healable ultraslippery surface can be used asa promising material in mitigating MIC.

Joint Lattice-Reduction-Aided Precoder Design for Multiuser MIMO Relay System

( Hua Jiang ),( Hao Cheng ),( Lizhen Shen ),( Guoqing Liu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.7

Lattice reduction (LR) has been used widely in conventional multiple-input multiple-output (MIMO) systems to enhance the performance. However, LR is hard to be applied to the relay systems which are important but more complicated in the wireless communication theory. This paper introduces a new viewpoint for utilizing LR in multiuser MIMO relay systems. The vector precoding (VP) is designed along with zero force (ZF) criterion and minimum mean square error (MMSE) criterion and enhanced by LR algorithm. This implementable precoder design combines nonlinear processing at the base station (BS) and linear processing at the relay. This precoder is capable of avoiding multiuser interference (MUI) at the mobile stations (MSs) and achieving excellent performance. Moreover, it is shown that the amount of feedback information is much less than that of the singular value decomposition (SVD) design. Simulation results show that the proposed scheme using the complex version of the Lenstra--Lenstra--Lovasz (LLL) algorithm significantly improves system performance.

Lead ion detection using glutathione-functionalized aluminum gallium nitride/gallium nitride high-electron-mobility transistors

Dong Xiaohu,Jiang Xuecheng,Gu Yan,Wei Chunlei,Xie Zhijian,Zhang Qi,Qian Weiying,Zhang Xiangyang,Zhu Chun,Lu Naiyan,Chen Guoqing,Yang Guofeng 한국물리학회 2023 Current Applied Physics Vol.50 No.-

This work presents a new approach for lead ion detection (Pb2+) using an aluminum gallium nitride/gallium nitride (AlGaN/GaN) high-electron-mobility transistor (HEMT) sensor. The AlGaN/GaN HEMT structure of the sensor was realized by functionalizing the gate area with glutathione (GSH). The crystalline and surface qualities of the AlGaN film were measured through X-ray diffraction and atomic force microscopy. The response of the sensor was measured in terms of the source–drain current with varying concentrations of Pb2+ ions at a fixed drain-to-source voltage. The sensitivity of the sensor was 29.3 μA/(mg/L), and it exhibited high selectivity toward Pb2+. The results show that using the GSH-functionalized AlGaN/GaN HEMT sensor is a promising strategy for Pb2+ ion detection.

Nonlinear vibration analysis of composite laminated trapezoidal plates

Fengming Li,Guoqing Jiang,Xinwu Li 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.2

Nonlinear vibration characteristics of composite laminated trapezoidal plates are studied. The geometric nonlinearity of the plate based on the von Karman's large deformation theory is considered, and the finite element method (FEM) is proposed for the present nonlinear modeling. Hamilton's principle is used to establish the equation of motion of every element, and through assembling entire elements of the trapezoidal plate, the equation of motion of the composite laminated trapezoidal plate is established. The nonlinear static property and nonlinear vibration frequency ratios of the composite laminated rectangular plate are analyzed to verify the validity and correctness of the present methodology by comparing with the results published in the open literatures. Moreover, the effects of the ply angle and the length-high ratio on the nonlinear vibration frequency ratios of the composite laminated trapezoidal plates are discussed, and the frequency-response curves are analyzed for the different ply angles and harmonic excitation forces.

Flow Behaviour and Constitutive Modelling of a Ferritic Stainless Steel at Elevated Temperatures

Jingwei Zhao,Zhengyi Jiang,Guoqing Zu,Wei Du,Xin Zhang,Laizhu Jiang 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.3

The flow behaviour of a ferritic stainless steel (FSS) was investigated by a Gleeble 3500 thermal-mechanical test simulator over the temperature range of 900-1100 °C and strain rate range of 1-50 s -1 . Empirical and phenomenological constitutive models were established, and a comparative study was made on the predictability of them. The results indicate that the flow stress decreases with increasing the temperature and decreasing the strain rate. High strain rate may cause a drop in flow stress after a peak value due to the adiabatic heating. The Zener-Hollomon parameter depends linearly on the flow stress, and decreases with raising the temperature and reducing the strain rate. Significant deviations occur in the prediction of flow stress by the Johnson-Cook (JC) model, indicating that the JC model cannot accurately track the flow behaviour of the FSS during hot deformation. Both the multiple-linear and the Arrhenius-type models can track the flow behaviour very well under the whole hot working conditions, and have much higher accuracy in predicting the flow behaviour than that of the JC model. The multiple-linear model is recommended in the current work due to its simpler structure and less time needed for solving the equations relative to the Arrhenius-type model.

Genome-wide identification of microRNAs and phased siRNAs in soybean roots under long-term salt stress

Qian Wang,Yingxia Yang,Guoqing Lu,Xianjun Sun,Youren Feng,Shuangyong Yan,Huiyuan Zhang,Qiyan Jiang,Hui Zhang,Zheng Hu,Rui Chen 한국유전학회 2020 Genes & Genomics Vol.42 No.11

Background Salinity stress, as the key limiting factor for agricultural productivity, can activate a series of molecular responses and alter gene expression in plants. Endogenous regulatory small RNAs, such as microRNAs (miRNAs) and phased siRNAs (phasiRNAs), play crucial roles during stress adaptation and prevent the injury from environmental circumstances. Objective To identify long-term salt stress responsive miRNAs and phasiRNAs as well as their associated genes and pathways in soybean roots. Methods Small RNA and degradome sequencing strategies were applied to genome widely investigate miRNAs and phasiRNAs in soybean roots under control and long-term salt stress conditions. Results In this study, stringent bioinformatic analysis led to the identifcation of 253 conserved and 38 novel miRNA candidates. Results of expression profling, target and endogenous target mimics predictions provided valuable clues to their functional roles. Furthermore, 156 genes were identifed to be capable of generating 21 nt and 24 nt phasiRNAs, in which 37 candidates were confrmed by degradome data for miRNA-directed cleavage. Approximately 90% of these phasiRNA loci were protein coding genes. And GO enrichment analysis pointed to “signal transduction” and “ADP binding” entries and refected the functional roles of identifed phasiRNA genes. Conclusion Taken together, our fndings extended the knowledge of salt responsive miRNAs and phasiRNAs in soybean roots, and provided valuable information for a better understanding of the regulatory events caused by small RNAs underlying plant adaptations to long-term salt stress.