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Water-oxygen interaction on marcasite(101)surface:DFT calculation

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International Journal of Mining Science and Technology 2022年第1期32卷 191-199页

作者： junjie zhang Yuqiong Li Jianhua Chen School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials Guangxi UniversityNanning 530004China

Marcasite(FeS2)is widespread in nature,its oxidation plays a vital role in acid mine drainage,mineral resource recovery,and photoelectric material *** this paper,the oxidation mechanism of marcasite has been studied for the first time using density functional theory(DFT).It is found that,unlike the oxidation of pyrite,the oxidation of marcasite merely occurs at surface S *** the coexistence of water and oxygen,S atoms around surface Fe atoms are replaced by O *** surface S sites are initially oxidized to form S==O bonds,and continue to adsorb oxygen to gradually generate SO3^2-,SO4^2-species,and eventually *** this process,H2O molecules participate in neither oxidation nor dissociation,and they are adsorbed on surface Fe sites in the form of molecules,i.e.,all O atoms in SO4^2-derive from oxygen rather than water molecules.

关键词： Marcasite Surface oxidation Adsorption Density functional theory

N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao zhang Xiaoyan zhang junjie zhang Shen’gen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

Yb^(3+)-doped Fluorophosphate Glass with High Cross Section and Lifetime

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Journal of Materials Science & Technology 2010年第10期26卷 921-924页

作者： Liyan zhang Yuxin Leng junjie zhang Lili Hu Key Laboratory of Materials for High Power Laser Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China

Yb3＋ doped fluorophosphate （FP/Yb） glasses with emission cross section and fluorescence lifetime as high as 0.8388×10-20 cm 2 and 2.3 ms were developed,and AlF3 content is proved to decrease the lifetime *** scale glass casting procedure shows high Tx-Tg doesn t make better casting crystallization stability in *** Yb laser is difficult to be obtained in FP glass,a 230 mw laser was still achieved from 2 mm thick samples under 976 nm LD excitation because of the large gain parameter（σemiτf） of the FP/Yb *** test also proved the relationship between laser output and gain *** with its wide and flat effective gain property,this FP/Yb glass is a practical new potential material for low power ultra-short pulse application.

关键词： FP15/Yb glass Crystallization stability Gain parameter

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

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

Phase evolution and properties of glass ceramic foams prepared by bottom ash,fly ash and pickling sludge

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International Journal of Minerals,Metallurgy and Materials 2022年第3期29卷 563-573页

作者： junjie zhang Xiaoyan zhang Bo Liu Christian Ekberg Shizhen Zhao Shengen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Shunde Graduate School University of Science and Technology BeijingFoshan 528399China Nuclear Chemistry and Industrial Material Recycling Department of Chemistry and Chemical EngineeringChalmers University of TechnologyGothenburg 41296Sweden

Municipal solid waste incineration products of bottom ash(BA),fly ash(FA),and pickling sludge(PS),causing severe environ-mental pollution,were transformed into glass ceramic foams with the aid of CaCO3 as a pore-foaming agent during *** effect of the BA/FA mass ratio on the phase composition,pore morphology,pore size distribution,physical properties,and glass structure was investigated,with results showing that with the increase in the BA/FA ratio,the content of the glass phase,Si-O-Si,and Q3Si units decrease *** glass transmission temperature of the mixture was also *** combined,the glass viscosity decreases,causing bubble coalescence and uneven pore *** ceramic foams with uniform spherical pores are *** the content of BA,FA,and PS are 35wt%,45wt%,and 20wt%,respectively,contributing to high performance glass ceramic foams with a bulk density of 1.76 g/cm3,porosity of 56.01%,and compressive strength exceeding 16.23 *** versatile and low-cost approach provides new insight into synergistically recycling solid wastes.

关键词： glass ceramic foams bottom ash fly ash picking sludge pore structure glass units

Atomistic investigation of ablation of amorphous polystyrene under femtosecond laser pulse

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Science China(Physics,Mechanics & Astronomy) 2015年第3期58卷 64-70页

作者： HUANG YanHua SONG ChengWei zhang junjie SUN Tao Research Center of Laser Fusion China Academy of Engineering Physics Center for Precision Engineering Harbin Institute of Technology

In the present work we elucidate the thermodynamic mechanisms of femtosecond(fs)laser ablation of amorphous polystyrene by means of molecular dynamics(MD)*** effects of extrinsic parameter of laser pulse intensity and intrinsic parameter of molecular architecture on the laser ablation are further *** results show that the laser ablation-induced polymeric material removal is achieved by evaporation from the surface and expansion within the ***,inter-chain sliding and intra-chain change also play important roles in the microscopic deformation of the *** is found that both the laser pulse intensity and the arrangement of phenyl groups have significant influence on the fs laser ablation of polystyrene.

关键词： polystyrene femtosecond laser ablation molecular dynamics laser intensity molecular architecture

An ultrathin,rapidly fabricated,flexible giant magnetoresistive electronic skin

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Microsystems & Nanoengineering 2024年第4期10卷 305-312页

作者： junjie zhang Zhenhu Jin Guangyuan Chen Jiamin Chen State Key Laboratory of Transducer Technology Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100190China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China College of Materials Sciences and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China

In recent years,there has been a significant increase in the prevalence of electronic wearables,among which flexible magnetoelectronic skin has emerged as a key *** technology is part of the rapidly progressing field of flexible wearable electronics,which has facilitated a new human perceptual development known as the magnetic ***,the magnetoelectronic skin is limited due to its low sensitivity and substantial field limitations as a wearable electronic device for sensing minor magnetic ***,achieving efficient and non-destructive delamination in flexible magnetic sensors remains a significant challenge,hindering their *** this study,we demonstrate a novel magnetoelectronic touchless interactive device that utilizes a flexible giant magnetoresistive sensor *** flexible magnetic sensor array was developed through an electrochemical delamination process,and the resultant ultra-thin flexible electronic system possessed both ultra-thin and non-destructive *** flexible magnetic sensor is capable of achieving a bending angle of up to 90 degrees,maintaining its performance integrity even after multiple repetitive bending *** study also provides demonstrations of non-contact interaction and pressure *** research is anticipated to significantly contribute to the advancement of highperformance flexible magnetic sensors and catalyze the development of more sophisticated magnetic electronic skins.

关键词： electronic magneto utilize

Automatic tunnel lining crack detection via deep learning with generative adversarial network-based data augmentation

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Underground Space 2023年第2期9卷 140-154页

作者： Zhong Zhou junjie zhang Chenjie Gong Wei Wu School of Civil Engineering Central South UniversityChangsha 410075China Hunan Tieyuan Civil Engineering Testing Co LtdChangsha 410075China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

Aiming at solving the challenges of insufficient data samples and low detection efficiency in tunnel lining crack detection methods based on deep learning,a novel detection approach for tunnel lining crack was proposed,which is based on pruned You Look Only Once v4(YOLOv4)and Wasserstein Generative Adversarial Network enhanced by Residual Block and Efficient Channel Attention Module(WGAN-RE).In this study,a data augmentation method named WGAN-RE was proposed,which can achieve the automatic generation of crack images to enrich data ***,YOLOv4 was selected as the basic model for training,and a pruning algo-rithm was introduced to lighten the model size,thereby effectively improving the detection *** Precision(AP),F1 Score(F1),model size,and Frames Per Second(FPS)were selected as evaluation indexes of the model *** indicate that the storage space of the pruned YOLOv4 model is only 49.16 MB,which is 80%compressed compared with the model before *** addition,the FPS of the model reaches 40.58f/s,which provides a basis for the real-time detection of tunnel lining *** also demon-strate that the F1 score and AP of the pruned YOLOv4 are only 0.77%and 0.50%lower than that before pruning,***,the pruned YOLOv4 is superior in both model accuracy and efficiency compared with YOLOv3,SSD,and Faster RCNN,which indi-cated that the pruned YOLOv4 model can realize the accurate,fast and intelligent detection of tunnel lining cracks in practical tunnel engineering.

关键词： Tunnel engineering Lining cracks Target detection Deep learning YOLOv4 Generative adversarial network