Phase Transition and Magnetic Transport Properties for Single Crystal of (Ca<SUB>0.42</SUB>Sr<SUB>0.58</SUB>)₃Ru₂O₇

Qing Ji,Ming Fu,Jianjian Ge,Bin Qian,Zhe Qu,Z.Q. Mao,X.S. Wu 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Appearance-based Robot Visual Servo via a Wavelet Neural Network

Qingjie Zhao,Zengqi Sun,Fuchun Sun,Jihong Zhu 대한전기학회 2008 International Journal of Control, Automation, and Vol.6 No.4

This paper proposes a robot visual servo approach based on image appearance and a wavelet function neural network. The inputs of the wavelet neural network are changes of image features or the elements of image appearance vector, and the outputs are changes of robot joint angles. Image appearance vector is calculated by using eigen subspace transform algorithm. The proposed approach does not need a priori knowledge of the robot kinematics, hand-eye geometry and camera models. The experiment results on a real robot system show that the proposed method is practical and simple.

Average Consensus Seeking of High-order Continuous-time Multi-agent Systems with Multiple Time-varying Communication Delays

Qingjie Zhang,Yifeng Niu,Lin Wang,Lincheng Shen,Huayong Zhu 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.6

The average consensus problem of high-order multi-agent systems with multiple time-varying communication delays is investigated in this paper. By using the idea of state decomposition, the condition for guaranteeing average consensus is converted into verifying the stability of zero equi-librium of disagreement system. Considering multiple time-varying communication delays, Lyapunov-Krasovskii approach in time-domain is employed to analyze the stability of zero equilibrium. With the help of Free-weighting Matrices (FWM) approach, the tolerant upper bounds on communication delays can be obtained through solving feasible linear matrix inequalities (LMIs). Delay-dependent stability criteria for both strongly-connected fixed and switching topologies are provided in the main results. Further, the conclusion is extended to the case of jointly-connected switching topologies. Numerical examples and simulation results are given to demonstrate the effectiveness and the benefit on reducing conservativeness of the proposed method.

Cytotoxic Tirucallane Triterpenoids from the Stem Bark of Melia toosendan

Qingjie Zhao,Hai-Sheng Chen,Yan Song,Chuanwei Feng 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.11

Three new tirucallane triterpenoids, 3β,16-dihydroxy-25-hydroperoxytirucalla-7,23(24)-dien-6-oxo acid (1), 3β,16β-hydroxytirucalla-7,24(25)-dien-21,23-olide (2), and 3β,16β-hydroxytirucalla-7,24(25)-dien-6-oxo-21,23-olide (3) were isolated from the 70% ethanol extract of the stem bark of Melia toosendan. Their structures were determined on the basis of 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) analyses. The isolated compounds were evaluated in vitro for cytotoxic activities against A549, SK-OV-3, SK-MEL-2 and HCT15 tumor cell lines. Compounds 2 and 3 exhibited significant cytotoxic activities against the four tested cell lines with IC50 values of 3.4-5.7 μg/mL and 3.2-5.0 μg/mL, respectively.

Effect of the content of light-burned alumina-spinel composite on the slag resistance of corundum-spinel refractory castables

Qingjie Chen 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.10

Corundum-spinel castable is widely used in ladles. The type of spinel impacts the slag resistance of castables. Spinel formedin situ enhances penetration resistance but pre-synthesized spinel enhances corrosion resistance of castable. A light-burnedalumina-spinel composite (LBC) was used as spinel source in this study for a balance between the penetration and corrosionresistance. The effects of the LBC content on the penetration and corrosion resistance of the castables were studied by meansof crucible test. The phase compositions and lattice distortions of the spinels in alumina-spinel composites were studied by Xraydiffractometry (XRD) and the microstructures of the samples eroded were studied by scanning electron microscopy(SEM). The results indicated that the penetration resistance increased and corrosion resistance of slag decreased withincreasing in LBC content because of its smaller crystallite size and higher lattice distortion, as well as smaller particle size. The optimized LBC content is 17.6 wt%.

Cadre Rotation and Campaign Mobilization in China's Anticorruption Enforcement

Qingjie Zeng 동아시아연구원 2017 Journal of East Asian Studies Vol.17 No.2

In authoritarian regimes, anticorruption measures are fundamentally mechanisms of controlling agents at various levels. To do this, the principal can either rely on routine bureaucratic management or resort to ad hoc, intense mobilization to discipline its agents. Using China as a case study, this article explores which mode of top-down control exerts greater influence on the pattern of anticorruption enforcement. We focus on the cadre rotation system as an example of routine management techniques and examine its effects on provincial level enforcement. We also investigate how provinces respond to the central government’s periodic call to intensify anticorruption efforts. Based on provincial enforcement data from 1998 to 2013, our analysis finds that the proportion of rotated officials has little impact on enforcement outcomes. Rather, the vigor of enforcement in the provinces responds strongly to national policy priorities, suggesting a highly centralized disciplinary system. Moreover, provinces of greater political importance are under more central pressure to conform. The findings challenge the often-made argument that stable institutions are effective in fostering top-down control in authoritarian regimes, and suggest that campaign mobilization continues to be an essential instrument at the dictator’s disposal.

Monoecism Algorithm in the Application of E-commerce Information Security

Qingjie Zhang,Jianming Zhu,Xiaoxu Wang,Yapan Li 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.3

With the development of e-commerce industry, the security of business information has attracted a lot of attention. The paper [1] puts forward the monoecism watermarking algorithm. The algorithm divides image into two parts: ROI (Region of interest) and RONI (Region Of Non Interest), and respectively deal with the two parts. Female watermark and male watermark are embedded into the RONI at the same time, and generate embedding watermark of the image. As is known to all, the integrity of ROI is also very important in e-commerce. This paper tries to apply the monoecism watermarking algorithm to e-commerce information security. The author gives six applications of the algorithm in electronic commerce that is graphical physical paper, electronic paper anti-counterfeiting, electronic seal, copyright protection, digital fingerprint generation, secure communication protection. This author introduced the embedding watermark and extracting watermark process and detection process of monoecism watermark algorithm. Through the analysis of simulation experiment of six application fields of monoecism watermark algorithm in the e-commerce information security, the simulation experiment has verified the validity of the algorithm. In a word, this paper has discussed the general rules of selecting ROI and the specific rules of selecting ROI in e-commerce applications. The simulation results are given, and the satisfactory results have been achieved.

Network Information Security Research based on the Grey Matter Element Analysis Method

Qingji Tian 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.10

With the progress of science and technology and the development of society, computer network information security becomes a social problem. In this paper, according to the characteristics of computer network information, the influencing system of computer network information security is constructed. Using matter element analysis method and grey theory to establish the grey matter-element model of the computer network information security, computer network information security can be divided into four grey clustering levels, according to the results of the expert scoring to determine the grey clustering level of computer network information security, which provides a professional, scientific and reasonable method for studying computer network information security.

Coal Chemical Looping Gasification for Syngas Generation Using an Iron-Based Oxygen Carrier

Guo, Qingjie,Cheng, Yu,Liu, Yongzhuo,Jia, Weihua,Ryu, Ho-Jung American Chemical Society 2014 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.53 No.1

<P>The chemical-looping gasification (CLG) of coal is a clean and effective technology for syngas generation. Sharing principles with chemical-looping combustion (CLC), CLG also uses oxygen carriers to transfer lattice oxygen to the fuel. Investigations into CLG with different O/C ratios are carried out in a fluidized bed reactor with steam used as the gasification–fluidization medium. The effect of the active component content of the oxygen carrier on the gas selectivity is performed, and reaction mechanisms between the Fe<SUB>2</SUB>O<SUB>3</SUB> oxygen carrier and coal with steam as the gasification agent are discussed. Moreover, we also assessed the reactivity of the CaO-decorated iron-based oxygen carrier particles in multicycle reactions. The carbon conversion efficiency is increased from 55.74 to 81% with increasing O/C ratio, whereas the content of H<SUB>2</SUB> first decreases and then increases. The addition of CaO can increase the carbon conversion efficiency and the gasification rate substantially and reduce the generation rate of H<SUB>2</SUB>S from 1.89 × 10<SUP>–3</SUP> to 0.156 × 10<SUP>–3</SUP> min<SUP>–1</SUP>. Furthermore, X-ray diffraction (XRD) images indicate that the CaO-decorated iron-based oxygen carrier particles were completely regenerated after six redox cycles. Finally, the peak fitting of gasification reaction rate curves is used to explore the reaction mechanism between coal char and the CaO-decorated iron-based oxygen carrier, indicating that the reactions in the CLG include three stages: the complex reactions involved an oxygen carrier, coal char, and steam; the gasification of coal char; and the reduction of Fe<SUB>3</SUB>O<SUB>4</SUB> to FeO. The two-segment modified random pore model (MRPM) fits the experiment data well.</P>

Nonlinear stability of the upper chords in half-through truss bridges

Wen Qingjie,Yue Zixiang,Liu Zhijun 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.3

The upper chords in half-through truss bridges are prone to buckling due to a lack of the upper transverse connections. Taking into account geometric and material nonlinearity, nonlinear finite-element analysis of a simple supported truss bridge was carried out to exhibit effects of different types of initial imperfections. A half-wave of initial imperfection was proved to be effective in the nonlinear buckling analysis. And a parameter analysis of initial imperfections was also conducted to reveal that the upper chords have the greatest impact on the buckling, followed by the bottom chords, vertical and diagonal web members. Yet initial imperfections of transverse beams have almost no effect on the buckling. Moreover, using influence surface method, the combinatorial effects of initial imperfections were compared to demonstrate that initial imperfections of the upper chords play a leading role. Furthermore, the equivalent effective length coefficients of the upper chord were derived to be 0.2~ 0.28 by different methods, which implies vertical and diagonal web members still provide effective constraints for the upper chord despite a lack of the upper transverse connections between the two upper chords. Therefore, the geometrical and material nonlinear finite-element method is effective in the buckling analysis due to its higher precision. Based on nonlinear analysis and installation deviations of members, initial imperfection of l/500 is recommended in the nonlinear analysis of half-through truss bridges without initial imperfection investigation.