Numerical Simulation of the Creep Behavior of Beishan Deep Granite Tunnel under the Coupling Thermal -Stress Field

Jiawei Wang,Ju Wang,Zhichao Zhou,Peng Wu,Haoran Sun,Jiale Dou,Nan Li,Xianzhe Duan 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

This study conducts a three-dimensional numerical simulation of the creep behavior of deep granite tunnels at 560 meters underground during the coupled thermal-stress process, with an aim to elucidate the effect of the temperature and stress fields on the creep behavior of these deep hard rock tunnels. A 100-h creep period was set, and the mechanical structure of the experimental chamber was accurately replicated at a 1:1 scale, considering the actual mechanical structure of the granite tunnels in the Beishan underground laboratory. The simulation results can demonstrate that: 1) The maximum stress at 90°C and 50°C are 2.86 and 1.91 times than that at 23°C, respectively, demonstrating significant strain accumulation in the deep granite tunnels at the surface. This phenomenon can primarily be attributed to the thermal stress resulted from the coupling between temperature and stress. 2) The maximum creep at 90°C and 50°C is 16 and 3.5 times than that at 23°C. Under the influence of thermal coupling, the creep increases significantly with increasing temperature, indicating that temperature is an important factor influencing creep in granite. 3) Compared with variations in the stress field, the temperature field emerges as the most critical factor influencing granite creep.

The length of guide RNA and target DNA heteroduplex effects on CRISPR/Cas9 mediated genome editing efficiency in porcine cells

Jiawei Lv,Shuang Wu,Renyue Wei,Yan Li,Junxue Jin,Yanshuang Mu,Yu Zhang,Qingran Kong,Xiaogang Weng,Zhonghua Liu 대한수의학회 2019 Journal of Veterinary Science Vol.20 No.3

The clustered regularly interspaced short palindrome repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is a versatile genome editing tool with high efficiency. A guide sequence of 20 nucleotides (nt) is commonly used in application of CRISPR/Cas9; however, the relationship between the length of the guide sequence and the efficiency of CRISPR/ Cas9 in porcine cells is still not clear. To illustrate this issue, guide RNAs of different lengths targeting the EGFP gene were designed. Specifically, guide RNAs of 17 nt or longer were sufficient to direct the Cas9 protein to cleave target DNA sequences, while 15 nt or shorter guide RNAs had loss-of-function. Full-length guide RNAs complemented with mismatches also showed loss-of-function. When the shortened guide RNA and target DNA heteroduplex (gRNA:DNA heteroduplex) was blocked by mismatch, the CRISPR/Cas9 would be interfered with. These results suggested the length of the gRNA:DNA heteroduplex was a key factor for maintaining high efficiency of the CRISPR/Cas9 system rather than weak bonding between shortened guide RNA and Cas9 in porcine cells.

Biomimetic functional hydrogel particles with enhanced adhesion characteristics for applications in fracture conformance control

Jiawei Liu,Lin Li,Zhongzheng Xu,Yongpeng Sun,Yining Wu,Caili Dai 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

Fracture conformance control in reservoir can effectively improve water channel to increase crude oil displacementefficiency of subsequent waterflooding. Inspired by the remarkable underwater wet adhesionof mussel byssus, hydrogel particles which can adhere stably on the fracture rock surface in reservoir conditionscould achieve long-lasting reservoir control effect. In this work, the size-controllable biomimeticfunctional hydrogel particles were prepared by mechanical shearing after bulk hydrogel was constructedby catechol-functionalized polyacrylamide and phenolic resin crosslinking agent. The influence of solutionsalinity on the aggregation and adhesion of hydrogel particles was investigated via scanning electronmicroscope (SEM), colloidal probe atomic force microscope (AFM) and quartz crystal microbalance withdissipation (QCM-D). The results showed that hydrogel particles maintained well-dispersed state in lowsalinitywater, while exhibited significant adhesion and adsorption capacity to the silica surface in simulatedreservoir salinity water. This is of great importance to the practical applications that the hydrogelparticles would not show enhanced adhesion to rock surfaces until the reservoir salinity water was met,which was beneficial to the in-depth migration of hydrogel particles to achieve effective deep reservoirprofile control. Furthermore, the visible micro-model was designed and applied to evaluate profile controleffect of hydrogel particles, and the results showed that hydrogel particles could withstand waterflushing and adhere stably to the fracture surface. The waterflooding sweep efficiency was increasedremarkably from 20.3% ± 2.0% to 38.8% ± 2.0%. This work would help better understand the functionmechanism of hydrogel particles in reservoir control and provide novel and efficient method for the practicalapplication in enhanced oil recovery.

Research on Influence of Matrix Component on the Mechanical Behavior of Multiaxial Warp-knitted Composites

Jiawei Chen,Xiaoping Gao,Ke Zhao,Wei Wu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11

The mass ratio of curing agent to epoxy resin is one of the important factors affecting the behavior of matrix andcomposites. In this paper, the solution of curing agent to epoxy resin with different mass ratio (0.25, 0.30, 0.35 and 0.40) wasselected as matrix, quadriaxial warp-knitted fabric was selected as reinforcement, and the composites were manufactured byapplying vacuum assisted film infusion. Then the tensile and bending behavior of the composites was experimentallyinvestigated, and the curing degree and failure mechanism of the composites were analyzed with respect to thethermodynamic properties and the microscopic failure morphologies. The optimal mass ratio was obtained by applyingnonlinear fitting and verified by experiment, and a mathematical model was derived to predict the relationship between thestrength and the mass ratio. The results showed that the thermal stability, curing degree, tensile and bending strength of thespecimens increase firstly and then decrease with increase of the mass ratio. According to the tensile and bending strengthresults, the optimum mass ratio were obtained as 0.31 and 0.33 by applying nonlinear fitting to the experiment data. Theresults could lay a theoretical foundation for optimizing the mass ratio of matrix components, and improve the strength ofcomposites.

Clamping Error Calibration Algorithm of Aero-Engine Blade Surface Polishing

Dongbo Wu,Zesheng Wang,Jiawei Liang,Hui Wang,Kung Zhang,Jie Yu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.7

Polishing is an effective process method to improve the surface quality of aero-engine blade. The clamping error between fixture and blade leads to position error of blade surface and reduces processing quality. In this paper, a laser calibration system and a calibration algorithm are proposed to compensate clamping error. Firstly, theoretical point data of blade surface is obtained from CAD model, and the measurement point data of blade surface is obtained through laser sensor. A modified ICP algorithm is designed to calculate the coordinate transformation between the theoretical points and the measurement points. Secondly, Bezier surface is introduced to evaluate the calibration accuracy based on the distance between fitting surfaces rather than points. Finally, the point cloud registration is optimized by particle swarm optimization (PSO) algorithm based on the Bezier surface evaluation. The calibration algorithm combined ICP algorithm, Bezier surface evaluation and PSO algorithm to realize clamping error compensation. The quality of polished blade surface is consequently improved.

Identification method of nonlinear maneuver model for unmanned surface vehicle from sea trial data based on support vector machine

Gongxing Wu,Jiawei Zhang,Guofu Li,Linling Wang,Qiang Yu,Jiamin Guo 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

In order to solve the difficulty of modeling the unmanned surface vehicle (USV) nonlinear maneuver model, a combination identification method of linear hydrodynamic coefficients and nonlinear hydrodynamic coefficients based on support vector machine (SVM) is proposed. The identification principle of USV hydrodynamic coefficients is briefly introduced and a regression algorithm of the SVM is derived for the USV maneuver model. Then, the linear hydrodynamic coefficients of the hull are identified by using a series of USV turning test data at small water-jet angles. And the large water-jet angle turning motion test data and the identified linear hydrodynamic coefficients are used to identify the nonlinear hydrodynamic coefficients for USV. The fourth-order Runge-Kutta method is used to design the USV maneuver simulation program, and a series of USV turning motion simulation experiments are carried out. The simulation data is compared with the corresponding USV sea trial data. Through comparative analysis, it is shown that the USV maneuver mathematical model established in this paper can describe the maneuverability of the USV. It is feasible to use the combination method of SVM to identify the hydrodynamic coefficient of USV.

Energy Aware Wireless Sensor Network Low Energy Consumption Full Network Coverage Algorithm

Luo Yonghua,Wu Jiawei,Qiu Shangming 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.7

The energy aware based active node decision and the sensing directions thereof become the research hotspots of DNN (Directional Sensor Network). Therefore, an EACO (Energy aware-based coverage optimal) algorithm is proposed in this paper. Specifically, each cluster head decides the number of the active nodes of the cluster members and the sensing directions thereof according to the coverage area of the sensor nodes and the energy information thereof. Meanwhile, the dormancy mechanism is adopted to minimize the overlapping area among the clusters. The simulation result shows that the proposed EACO algorithm is improved in the aspects of coverage rate and network lifetime.

Augmented RBF metamodel for global sensitivity analysis enhanced by recursive evolution LHD and efficient K-fold cross-validation

Guosheng Li,Jiawei Yang,Wenjie Wang,Zixuan Zhang,Weihua Zhang,Zeping Wu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

This paper proposes an enhanced augmented radial basis function (eARBF) metamodel combining radial basis function and polynomial chaos expansions for global sensitivity analysis. First, the conditions required for the augmented radial basis function are constructed from the perspective of variance decomposition, after which the analytical expressions of the Sobol’ indices are deduced. To improve the generalization performance of ARBF, an anisotropic technique is proposed based on the local density of sample points. Furthermore, the recursive evolution LHD and efficient K-fold cross-validation method are adopted to reduce computational efforts. Five cases are presented to demonstrate the performance of the proposed approach. In all cases, eARBF yields satisfactory results with lower computational effort. The results indicate that the approach proposed in this paper is promising for GSA of engineering problems.

Microstructure and Magnetic Properties of Plasma-Sprayed Fe<SUB>73.5</SUB>Cu1Nb₃Si<SUB>13.5</SUB>B₉ Coatings

Xiaojun Ni,Xihui Bo,Jiawei Wu,Jinhua Guo,Zhichao Lu,Shaoxiong Zhou 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Optimizing the chlorine evolution reaction performance of Co(OH)2 catalyst for enhanced antifouling ability

Yating Peng,Peng Wang,Jiawei Li,Jiajia Wu,Feng Lin,Dun Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

Underwater optical instruments are commonly plagued by biofouling. As one of the most useful antifoulingstrategies, electrochemical chlorination is able to prevent biofouling efficiently, but the limited activityand selectivity in chlorine evolution reaction (CER) restrict its practical applications. To address thisproblem, we focus on the optimization of CER performance of cobalt-based catalysts. In this work, weprepared Co(OH)2 with different forms, morphologies, and intercalations. By adopting linear sweepvoltammetry and electrochemical active surface area analysis, it is demonstrated that the a-Co(OH)2exhibits better CER performance than b-Co(OH)2 does, and the manipulation of a-Co(OH)2 morphologycan help to further enhance CER performance. Meanwhile, the intercalation of a-Co(OH)2 plays a minorrole in the CER. Furthermore, based on the screened synthetic condition, the optimized a-Co(OH)2 wasapplied for practical antifouling examination, and its excellent antifouling ability was verified by theinvestigation on bacteria attachment and glass transmittance. The findings in this work not only enrichour understanding on the effects of synthetic conditions on CER performance of cobalt-based catalysts,but also provide useful insights into the development of electrochemical antifouling strategies.