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Synthesis of SrTiO_3 for immobilization of simulated HLW by SHS

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Journal of University of Science and Technology Beijing 2005年第4期12卷 357-359页

作者： Ruizhu Zhang junjie Hao Zhimeng Guo Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China North China Institute of Water Conservancy and Hydroelectric Power Zhengzhou 450045 China

Strontium titanate synroc samples were synthesized by self-propagating high-temperature synthesis （SHS）. Sr directly took part in the synthesis process. As a result, the loading content issue is basically resolved. The products were characterized by density, microhardness X-ray diffraction, and scanning electron microscopy （SEM/EDS）. The leaching rate was measured by the method of PCT （product consistency test）. The results indicate that the Sr^2＋-SrTiO3 compound is of high density, low leach rate and high stability and the synthesis process is feasible in technology and economy. It can be concluded that the strontium titanate synroc is a perfect material to immobilize HLW.

关键词： strontium titanate high-level waste (HLW) immobilization self-propagating high-temperature synthesis (SHS)

GLOBAL DYNAMICS OF A CHOLERA MODEL WITH TIME DELAY

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International Journal of Biomathematics 2013年第1期6卷 143-160页

作者： YUJIE WANG junjie WEI Department of Mathematics Harbin Institute of Technology Harbin 150001 Heilongjiang P. R. China Department of Mathematics Jilin Normal University Siping 136000 Jilin P. R. China

The global dynamics of a cholera model with delay is considered. We determine a basic reproduction number R0 which is chosen based on the relative ODE model, and establish that the global dynamics are determined by the threshold value R0. If R0 〈 1, then the infection-free equilibrium is global asymptotically stable, that is, the cholera dies out; If R0 〉 1, then the unique endemic equilibrium is global asymptotically stable, which means that the infection persists. The results obtained show that the delay does not lead to periodic oscillations. Finally, some numerical simulations support our theoretical results.

关键词： Cholera model delay Lyapunov functional global stability.

Effect of alkalis on deacetylation of konjac glucomannan in mechano-chemical treatment

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Particuology 2011年第3期9卷 265-269页

作者： Zhidong Pan junjie Meng Yanmin Wang School of Materials Science and Engineering South China University of Technology Guangzhou 510640 China Key Laboratory of Specially Functional Materials and Advanced Manufacturing Technology Ministry of Education South China University of Technology. Guangzhou 510640 China

This paper presents experimental results on the effect of alkalis such as NaOH, KOH and Ca（OH）2 on deacetylation of a konjac glucomannan （KGM） powder under mechano-chemical （MC） treatment, The results show that the alkalinity of modifiers is a dominant factor for deacetylation of KGM, In addition, characteristics, such as swelling property, viscous stability and thermal behavior of the deacetylated KGM are analyzed

关键词： Deacetylation Alkali Mechano-chemistry Konjac glucomannan

Gelcasting of 316L stainless steel

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Journal of University of Science and Technology Beijing 2007年第6期14卷 507-511页

作者： Yan Li Zhimeng Guo junjie Hao Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

A novel near-net process, gelcasting, was successfully used to prepare larger size 316L stainless steel parts with complex shape. In this study, the effects of process parameters on the viscosity of the slurry and the dry green strength were investigated. The results show that gas atomization （GA） powder is more suitable for gelcasting compared with water atomization （WA） powder. The maximum solid loading is 55vo1% for ball-milled slurry with GA powders. And the optimum amounts of monomers （acrylamide （AM）＋methylenebisacrylamide （MBAM）; the mass ratio, 30：1） and initiator in the AM system are 1.8% （based on the weight of metal powder） and 0.8%-1.4% （based on the weight of monomers）, respectively, at which, the maximum green strength obtained is 33.7 MPa. The mechanical properties of the sintered specimen are as follows： ultimate tensile strength, 493 MPa; yield strength, 162 MPa; and HRB, 72.

关键词： gelcasting 316L stainless steel complex-shape slurry green strength

Estimating the outgoing longwave radiation from the FY-3B satellite visible infrared radiometer Channel 5 radiance observations

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Chinese Science Bulletin 2011年第32期56卷 3480-3485页

作者： WU Xiao YAN junjie Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing 100081 China National Satellite Meteorological Center Beijing 100081 China

Based on the infrared radiation transfer model, the outgoing longwave radiation (OLR) and Channel 5 radiance of Fengyun-3B (FY-3B) satellite visible infrared radiometer (VIRR) were simulated for 3812 global soundings. Using regression analysis of the simulations, an inverse model, which connected the flux equivalent brightness temperature with the channel brightness temperature, was derived. By applying the model to the FY-3B VIRR L1 data, the global OLR data at the time of the passing of the FY-3B were processed. The quality of the data was validated by comparing it with that of the NOAA-18 satellite's advanced very high resolution radiometer (AVHRR). The validation results show root mean square errors in the range 10-13 W/M 2 when comparing the daily average OLR of the VIRR with that of the NOAA-18 AVHRR, and the correlation coefficients were in the range 0.97-0.98. The larger RMSE is mainly due to the different passing times of the two satellites for the specific locations on the Earth. An example of the OLR data and its preliminary applications are given.

关键词：红外辐射计向外长波辐射连接通道卫星辐射观测 OLR资料 AVHRR 估计

A hybrid multidimensional Riemann solver to couple self-similar method with MULTV method for complex flows

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Chinese Journal of Aeronautics 2021年第7期34卷 29-38页

作者： Feng QU Di SUN junjie FU Junqiang BAI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

Since proposed,the self-similarity variables based genuinely multidimensional Riemann solver is attracting more attentions due to its high resolution in multidimensional complex ***,it needs numerous logical operations in supersonic cases,which limit the method’s applicability in engineering problems *** order to overcome this defect,a hybrid multidimensional Riemann solver,called HMTHS(Hybrid of MulTv and multidimensional HLL scheme based on Self-similar structures),is *** simulates the strongly interacting zone by adopting the MHLLES(Multidimensional Harten-Lax-van Leer-Eifeldt scheme based on Self-similar structures)scheme at subsonic speeds,which is with a high resolution by considering the second moment in the similarity ***,it adopts the MULTV(Multidimensional Toro and Vasquez)scheme,which is with a high resolution in capturing discontinuities,to simulate the flux at supersonic *** numerical experiments,including both one-dimensional cases and twodimensional cases,are ***-dimensional moving contact discontinuity case and sod shock tube case suggest that HMTHS can accurately capture one-dimensional expansion waves,shock waves,and linear contact ***-dimensional cases,such as the double Mach reflection case,the supersonic shock/boundary layer interaction case,the hypersonic flow over the cylinder case,and the hypersonic viscous flow over the double-ellipsoid case,indicate that the HMTHS scheme is with a high resolution in simulating multidimensional complex ***,it is promising to be widely applied in both scholar and engineering areas.

关键词： Complex flows Computational fluid dynamics Multidimensional Riemann solver Self-similar

Fast detection algorithm for cracks on tunnel linings based on deep semantic segmentation

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Frontiers of Structural and Civil Engineering 2023年第5期17卷 732-744页

作者： Zhong ZHOU Yidi ZHENG junjie ZHANG Hao YANG School of Civil Engineering Central South UniversityChangsha 410000China National Engineering Research Center of Highway Maintenance Technology Changsha University of Science&TechnologyChangsha 410000China School of Traffic and Transportation Engineering Changsha University of Science&TechnologyChangsha 410000China

An algorithm based on deep semantic segmentation called LC-DeepLab is proposed for detecting the trends and geometries of cracks on tunnel linings at the pixel *** proposed method addresses the low accuracy of tunnel crack segmentation and the slow detection speed of conventional models in complex *** novel algorithm is based on the DeepLabv3+network framework.A lighter backbone network was used for feature ***,an efficient shallow feature fusion module that extracts crack features across pixels is designed to improve the edges of crack ***,an efficient attention module that significantly improves the anti-interference ability of the model in complex backgrounds is *** classic semantic segmentation algorithms(fully convolutional network,pyramid scene parsing network,U-Net,and DeepLabv3+)are selected for comparative analysis to verify the effectiveness of the proposed *** experimental results show that LC-DeepLab can accurately segment and highlight cracks from tunnel linings in complex backgrounds,and the accuracy(mean intersection over union)is 78.26%.The LC-DeepLab can achieve a real-time segmentation of 416×416×3 defect images with 46.98 f/s and 21.85 Mb parameters.

关键词： tunnel engineering crack segmentation fast detection DeepLabv3+ feature fusion attention mechanism

Effect of swirling addition on the liquid mixing performance in a T-jets mixer

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Chinese Journal of Chemical Engineering 2022年第10期50卷 108-116页

作者： Chunhui Li Bin Wu junjie Zhang Peicheng Luo School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China Hubei Sanjiang Aerospace Jianghe Chemical Technology Co. LtdYichang 444200China

Swirling addition to the stream is beneficial for the fluid *** work aims to study the mixing process intensification in a conventional T-jets mixer by the swirling *** experimental verification by the planar laser-induced fluorescence technique,large eddy simulation with the dynamic kinetic energy sub-grid stress model is used to predict how the swirling strength(in terms of swirling number,S_(w))and swirling directions affect the mixing performance,*** tracer concentration distribution,mixing time,and turbulent characteristics in the T-jets mixers,Predictions show that the swirling strength is the key factor affecting the mixing efficiency of the *** overall mixing time,τ_(90),can be significantly reduced by increasing S_(w).Vortex analysis shows that more turbulent eddies appear in the collision zone and the turbulent kinetic energy dissipation rate increases obviously with the swirling *** S_(w) is kept constant,the mixing process can be accelerated and intensified by adding swirling to only one stream,to both streams with the opposite swirling directions,or to both streams with the same swirling *** of the mixing process by enlarging the mixer size or increasing the flow rates is also ***,this work provides a new strategy to improve the mixing performance of the traditional T-jets mixers by the swirling addition.

关键词： Mixing T-jets mixer Swirling Computational fluiddynamics(CFD) Large eddysimulation

Study on the evolution of solid–liquid–gas in multi-scale pore methane in tectonic coal

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Chinese Journal of Chemical Engineering 2024年第7期71卷 122-131页

作者： junjie Cai Xijian Li Hao Sui Honggao Xie College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Mining College Guizhou UniversityGuiyang 550025China

The rich accumulation of methane(CH_(4))in tectonic coal layers poses a significant obstacle to the safe and efficient extraction of coal seams and coalbed *** coal samples from three geologically complex regions were selected,and the main results obtained by using a variety of research tools,such as physical tests,theoretical analyses,and numerical simulations,are as follows:22.4–62.5 nm is the joint segment of pore volume,and 26.7–100.7 nm is the joint segment of pore specific surface *** the dynamic gas production process of tectonic coal pore structure,the adsorption method of methane molecules is“solid–liquid adsorption is the mainstay,and solid–gas adsorption coexists”.Methane stored in micropores with a pore size smaller than the jointed range is defined as solid-state *** within the jointed range,which transition from micropore filling to surface adsorption,are defined as gaseous *** outside the jointed range,where solid–liquid adsorption occurs,are defined as liquid *** evolution of pore structure affects the methane adsorption mode,which provides basic theoretical guidance for the development of coal seam resources.

关键词： Tectonic coal Multiscale pore structure Methane adsorption Micropore filling Monolayer Molecular simulation