Enhanced anticorrosion of methyl acrylate by covalent bonded N-alkylpyridinium bromide for X70 steel in 5 M HCl

Guangqiang Xia,Xiaohui Jiang,Limei Zhou,Yinwen Liao,Ming Duan,Hu Wang,Qiang Pu,Jie Zhou 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-

Methyl acrylate connects covalently with alkylpyridinium bromide to build N-alkyl-3-(2-methox-ycarbonyl-vinyl)pyridinium bromide (MPA-n, n = 8–14). MPA-n inhibited X70 steel from corrosion in5 M HCl with inhibition efficiency of 98% and the inhibition capacity was in the order of MPA-14 > MPA-12 > MPA-10 > MPA-8. Quantum chemical calculation unveiled that MPA-n adsorbed on iron surface byO atom in MA moiety offering electrons to d orbital of iron and by p* orbital of pyridinium acceptingelectrons from iron, and MPA-n with longer alkylchain possessed higher EHOMO, lower DE, largermolecular volume and dipole moment, all suggesting the same corrosion inhibition order as that inexperiments

Cooperative Spectrum Sharing in Cognitive Radio Networks : A Centralized Contracted-Based Approach

Guangqiang Shi,Ying Liu,Xiaomin Mu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.3

In this paper, we study the relay-based communication schemes for cooperative spectrum sharing among multiple primary users (PUs) and multiple secondary users (SUs) with incomplete information. Inspired by contract theory, we model the network as a labor market. In this market, PUs and SUs are regarded as employer and employee respectively. Each PU proposes certain contracts to attract the SUs, the contract include relay power and spectrum access time, each SU maximize its utility by selecting the most suitable contract. But PUs and SUs have conflicting objectives in contract content. To tackle this problem, we put forward to a centralized maximizing expectation utility scheme, which convert the optimal contract design into an optimization problem. After that, a approximate method for solving the optimization problem is proposed. Simulation results show that the losses of PUs’ total utilities caused by incomplete information and approximate algorithm are relatively small, especially when the number of SUs is very large.

Mechanical Analysis of Woven Composites Through Experimental Investigation and Multiscale Numerical Simulation

Guangqiang Fang,Peng Qu,Zhengli Cao,Feizhou Shi 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

In this paper, the mechanical properties of a single-ply woven composites are investigated through a combinationof multiscale numerical simulation and experimental test. The tensile experiments of three woven structures with differentthread counts, 4.5+4.0, 5.5+7.0 and 5.5+5.0, are conducted. A multiscale numerical method is proposed in order tounderstand the influence mechanism of thread count on the mechanical properties. The numerical predictions have a goodagreement with the experimental results. Many unique characteristics of the single-ply woven composites have beenobserved, such as the clearly nonlinear mechanical behavior of samples with large thread count, the positive transversalnormal strain during the initial phase of longitudinal uniaxial tension and the breakage morphology in relation to threadcount. The M/L ratio is proposed in this paper to investigate the effect of the difference in the thread count between warp andfill direction on the mechanical behavior. The M/L ratio of thread count of 5.5+7.0 specimen is larger than 4.5+4.0 and5.5+5.0 by 38 % and 41 %, respectively, the corresponding M/T ratio of modulus is larger by 34 % and 29 %, and for strengthit is 23 % and 24 %. It is found that the increase of thread count in one direction improves the mechanical properties in thisdirection but reduces the equivalent elastic modulus and strength in the vertical direction. The simulated stress and straindistribution inside the RUC helps to better understand the influence mechanism of thread count on the mechanical propertiesof single-ply woven composites.

Effect of Thread Count on the Shear Mechanical Properties and Dynamic Mechanical Properties of Shape Memory Polymer Reinforced by Single-Ply Weave Fabric

Peng Qu,Guangqiang Fang,He Kong,Zhengli Cao,Jia Ma,Zhiyi Wang,An-Fu Guo,Shaoqing Wang,Xunjin Li,Xinran Shan 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

Shape memory epoxy polymer reinforced by single-ply weave fabric (SMEP-W) possesses high specific stiffness, good foldability, and satisfactory shape memory capability. These advantages make them promising materials for deployable space structures and increasingly attract research interests. Understanding the influence of weave structures on static and dynamic mechanical properties is crucial to structural design and mechanical response prediction. In this paper, a recently developed SMEP-W was prepared. The static shear experiments were conducted through modified shear test fixtures, and the stress field under static shear load was simulated through a multi-scale numerical modelling method. The dynamic mechanical analysis was carried out to evaluate the shape memory capability. SMEP-W shows nonlinear mechanical behavior under in-plane shear load, especially for the one with less thread count. The increase in the number of threads enhances the constraints between warp yarns and weft yarns, leading to an increase in shear modulus and reducing the scattering of static mechanical properties. The stress distribution on the yarns has the characteristic of center symmetry. High-stress regions appear on the overlapping surface of the crossover regions. Compared with shape memory epoxy polymer (SMEP), the glass transition temperature and damping coefficient of SMEP-W are significantly reduced, and the stiffness is remarkably enhanced. The difference in thread count between warp direction and weft direction does not notably affect the glass transition temperature and tan δ, but has a remarkable influence on the storage modulus. The present work could provide basic observation for understanding the influence of thread count on the shear mechanical properties and dynamic mechanical properties of SMEP-W.

In-Situ Observation of Grain Refinement in the Simulated Heat-Affected Zone of High-Strength Low-Alloy Steel by Zr-Ti Combined Deoxidation

Bowen Zhou,Guangqiang Li,Xiangliang Wan,Yu Li,Kaiming Wu 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.2

The effect of Zr-Ti combined deoxidation on the grain refinement in the simulated coarse-grained heat-affected zone of a high-strength low-alloy steel was investigated by means of analytical characterization techniques such as in-situ microscopy, transmission electron microscopy, and electron backscattered diffraction analysis. Owing to the Zr-Ti combined deoxidation, a large amount of fine Zr-Ti oxide particles were formed in the steel and retarded the austenite grain growth during simulated welding thermal cycle. The austenite grains were small and uniform. The Mn can diffuse spontaneously from austenite to Zr-Ti oxide inclusion and MnS precipitated on ZrO2, which can form Mn depleted zone in the vicinity of inclusion. The acicular ferrite grains nucleated on intragranular Zr-Ti oxide inclusions in austenite grains grew in different directions and effectively divided the austenite grain into several finer and separate regions at intermediate temperature. The crystallographic grain size became small in the simulated coarse-grained heat-affected zone of Zr-Ti-killed steel due to the effective pinning effect by Zr-Ti oxide particles and acicular ferrite formation.

Dynamic Spectrum Access with Spatial Reuse

Ying Liu,Guangqiang Shi,Xiaomin Mu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.1

We investigate the problem of achieving utility function optimization for distributed channel selection using game theoretic solutions in opportunistic spectrum access system, where secondary users are spatially located and mutual interference only emerges between neighboring users. In addition, interference graph of spatial position is introduced to measure interference and evaluate the possible opportunities of spectrum access. Based on this we propose an optimization problem of minimizing loss throughput, which is solved by a game theory and an optimal channel selection set is derived. The main work of this paper is to prove that this game is an exact potential game, which has at least one pure strategy Nash equilibrium. Finally simulation results is given to verify the correctness of the theoretical analysis. Especially meanwhile after considering spatial reuse by users’ position, the system throughput is significantly increased, thus the spectrum utilization rate is effectively improved.

Gas-liquid two-phase flow in the axial clearance of liquid-ring pumps

Renhui Zhang,Lei Tian,Guangqiang Guo,Xuebing Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

In this study, the leakage flow in the axial clearance of a 2BEA-203 liquid-ring pump has been modeled through numerical simulation using the renormalization group k-ε turbulence model and the multiphase volume of fluid method. Numerical results show that the axial leakage flow reduces the inlet vacuum and efficiency of the liquid-ring pump. The gasliquid two-phase flow within the axial clearance region is completely separated. Several droplets are scattered outside the suction region, some of which flow back into the low-pressure suction region along the wall of the suction port. Given the axial asymmetry of the flow passage, the phase distribution within the impeller region is non-uniform along the axial direction. The numerically simulated pressure distribution within the axial clearance region accords well with the vortex distribution caused by the leakage flow. The leakage flow interacts with the impeller flow, and forms a corner vortex near the pressure side and a leakage vortex near the blade suction side. As the relative coordinate of the cross planes to the blade (sc −1 ) decreases from tip to hub, the corner vortex near the blade pressure side gradually weakens while the leakage vortex near the suction side gradually strengthens. These vortices mostly form in the suction and compression zones of the clearance region and significantly affect the overall pump efficiency. Findings of this study reveal the flow structure in the axial clearance of the liquid-ring pump and the interaction between the leakage and main flow.

Optimization Study on Bias Angle of a Swirl Burner with Tangential Inlet Air

LV Ziqiang,Lius Guangqiang,Liu Yingjie 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.3

In this paper numerical simulation and experimental study was carried out for a tangential inlet air swirl burner which is used for high heat value biomass gas. Study on the different inlet angle effects on Combustion by numerical method. The results of the study show that the 30 degree is the best. The intake angle burner 30 degrees were tested to verify the accuracy of simulation results. Through the comparative analysis of the trajectory and the velocity of the air, the method and the conclusion of the simulation study are reliable.

실제 규모의 자기유변 유체 감쇠기를 위한 동적 모델의 개발

정형조(Jung Hyung-Jo),Guangqiang Yang,Bilie F. Spencer Jr.,이인원(Lee In-Won) 대한토목학회 2002 대한토목학회논문집 A Vol.22 No.4A

Frequency and magnetic properties in the range of 10 kHz to 100 MHz for nanocrystal Fe -Co alloy

Yongsheng Liu,Jincang Zhang,Liming Yu,Guangqiang Jia,Yufeng Zhang,Xinyan Wang,Shixun Cao 한국물리학회 2004 Current Applied Physics Vol.4 No.5

Fe-based soft magnetic alloy with Co-doping was fabricated by high-energy milling. The X-ray diraction (XRD) results exhibita single phased structure,which could be regarded as BCC-like FeCo solid solution,was formed. Moreover,it has also been demonstrated that a nanocrystalline FeCo alloy was obtained and the evaluated grain sizes were about 712 nm. The frequency dependence of the initial permeability and magnetic losses,as well as DC-magnetization measurements,was systematically studiedthen. The results show that thefn (fn is the frequency when the curve of the No.n sample has a minimum value) shifts to the higherfrequency with the increasing Co content in the range of 10 kHz to 100 MHz,while the magnetic losses of the samples decrease withthe increasing Co content at the high frequency (800 kHz to 20 MHz). The Co-doping increases the cut-o frequencies of thesamples and makes the initial permeability to keep a constant value in a wider frequency range. The corresponding peak value of theinitial permeability as function of Co-doping concentration turns to the region of low Co concentration. For the long milling time,the loss apparently decreases beyond 1 MHz.