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Study on influence of key blasthole parameters on tunnel overbreak

Underground Space 2023年第2期9卷 76-90页

作者： zi-qiang li Zheng li Wei-wei Huang Xuan-ming Ding Hang Zhang School of Civil Engineering and Architecture Chongqing University of Science&TechnologyChongqing 401331China Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of EducationChongqing UniversityChongqing 400045China Chongqing City Construction Investment(Group)Co. Ltd.Chongqing 400023China School of Civil Engineering Chongqing University400045China

To determine the influence of key blasthole parameters on tunnel overbreak during blasting construction,an intelligent detection sys-tem for tunnel blasting construction is independently *** the key blasthole parameters and overbreak of a typical section of a single line tunnel under the condition of Class V surrounding rock are analyzed and *** actual data obtained is compared with the results of numerical simulations and theoretical *** results are as follows:(1)Quantitative analysis is performed based on the blasthole angle,opening position,and charge mass by the self-developed intelligent detection equipment for blasthole parameters,which can be used to guide the drilling *** scanning equipment for outline excavation can be used to image the actual excavation section in real-time and has the advantages of high precision and fast speed;(2)Tunnel overbreak can be regarded as consisting of two parts:the surrounding rock damage caused by the blasting load,and the collapse of the surrounding rock caused by the blasthole opening *** parameter of the peripheral hole will affect the tunnel overbreak;however,the key parameter is the blasthole opening position;(3)The distributions of the tunnel overbreak volume obtained with the theoretical analysis,finite element simulation,and measurements are basically *** the condition of Class V surrounding rock,the overbreak of this single line tunnel can reach 14.1–78.2 *** meet the specification requirements,the opening position and construction accuracy of the peripheral hole should be strictly controlled.

关键词： Tunnel blasting Blasthole parameters Tunnel overbreak Surrounding rock damage Smooth surface blasting

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Fatigue damage analysis of ballastless slab track in heavy-haul railway tunnels

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Underground Space 2022年第3期7卷 440-452页

作者： zi-qiang li Zheng li Wei-wei Huang Hong-rui Zhang Hang Zhang School of Civil Engineering and Architecture Chongqing University of Science&TechnologyChongqing 41331China Chongqing City Construction Investment(Group)Co. Ltd.Chongqing 400023China Key Laboratory of New Technology for Construction of Cities in Mountain Area Ministry of EducationChongqing UniversityChongqing 400045China School of Mechanical and Electrical Engineering Hainan UniversityHainan 570228China

A ballastless slab track,which is commonly used in the track structures of heavy-haul railway tunnels,was analysed based on field measurement data of the Fuyingzi Tunnel on the Zhangtang *** accordance with the measured data,the dynamic load thresholds and distributions on the surface and bottom of the ballastless slab track were investigated.A fatigue damage analysis of the ballastless slab track was performed based on the dynamic load time–history *** results show that the ballastless slab track can accomplish train load attenuation and reduce the dynamic load from heavy-haul trains by 47.22%from the surface to the *** addition,the distribution at the bottom of the ballastless slab track exhibited a triangular shape,and the dynamic load threshold at the line centre accounted for 78.67%of that at the track ***,the distribution at the surface was saddle-shaped;the dynamic load threshold at the track position accounted for 79.55%of that at the line centre *** fatigue damage of the ballastless slab track was analysed effectively by combining the measured data and the linear fatigue damage ***,the accuracy of the calculation results was verified based on the measured dynamic stress of the ballastless slab track *** dynamic action of the train load led to more-concentrated damage to the track bed,and the damage occurred earlier than that in the ordinary *** axle load was the primary influencing factor of the track bed fatigue damage,and the damage mainly occurred in the track *** results provide a theoretical basis for performing stress analysis and designing parameters for ballastless slab tracks in heavy-haul railway tunnels.

关键词： Heavy-haul railway tunnel Numerical simulation results Ballastless slab track Fatigue damage

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Solidification crack characteristics and sensitivity of peritectic steel

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1668-1679页

作者： Ya-qiang li Jian-hua liu zi-ming Wang Ying-ying li Yang He Xiao-wei li Department of Automotive Engineering Hebei Vocational University of Technology and EngineeringXingtai 054000HebeiChina Hebei Special Vehicle Modification Technology Innovation Center Hebei Vocational University of Technology and EngineeringXingtai 054000HebeiChina Institute of Engineering Technology University of Science and Technology BeijingBeijing 100083China School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhou 213164JiangsuChina

The characteristics and sensitivity of solidification cracks in peritectic steels were investigated using directional solidifi-cation *** cracks were observed in both hypoperitectic steels(12CrlMoV,15CrMo)and hyper-peritectic steel(20CrMo)during solidification at growth velocities of 15,50,and 80 pm/*** the dendritic boundaries,sulphide precipitates were found,promoting crack *** on the statistical analysis of interdendritic cracks in peritectic steels,the area ratio(RA)of interdendritic cracks in a directional solidification structure was proposed to evaluate the crack sensitivity of peritectic ***,the crack sensitivities of peritectic steels(12CrlMoV,15CrMo,and 20CrMo)were tested,evaluated,and compared with the surface crack rates of three types of steels produced from a steel *** results demonstrated that RA was in good agreement with that of the steel plant,and the crack sensitivity of 12CrlMoV steel was the strongest,followed by that of 15CrMo and 20CrMo ***,RA can be used to evaluate the crack sensitivity of peritectic steel.

关键词： Peritectic steel-Directional solidification Growth velocity Dendritic structure Solidification crack Crack sensitivity

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Facile synthesis of hierarchical NiO/NiFe_(2)O_(4) microsphere composite as efficient visible photocatalyst for 2,4-DCP degradation

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Rare Metals 2024年第4期43卷 1580-1588页

作者： Shabana Shaheen Shuai Xu Ji Bian Amir Zada zi-Qing Zhang Yang Qu li-qiang Jing Key Laboratory of Functional Inorganic Materials Chemistry(Ministry of Education) International Joint Research Center and Lab for Catalytic TechnologySchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin150080China Department of Chemistry Abdul Wali Khan UniversityMardan23200Pakistan

It is highly desired to develop efficient photocatalysts with recycling property for practical application to degrade toxic ***,nanosheet-assembled NiFe_(2)O_(4)microspheres with commendable activity are successfully synthesized by a facile solvothermal reaction with NH4F as the modifier,and their photoactivities are further improved by coupling with NiO through an in situ growth *** optimized nickel oxide(NiO)/nickel ferrite(NiFe_(2)O_(4))microsphere composite(5NiO/NFO-4)exhibits a satisfactory photocatalytic activity for 2,4-dichlorophenol(2,4-DCP)degradation under visible-light irradiation,which is attributed to its wide visible-light response,well-designed hierarchical structure and enhanced charge transfer and separation by coupling NiO as a high-level energy platform to accept ***,it is found that the NiO/NiFe_(2)O_(4)microsphere photocatalysts can be easily collected and recycled owing to the distinctive magnetic *** work provides a feasible route to rational design visible-light-driven photocatalysts with high-activity for environmental remediation and purification with good recyclability.

关键词： NiFe_(2)O_(4) microspheres NiO/Fe_(2)O_(4) composite Charge separation Visible-light photocatalysis 2 4-Dichlorophenol degradation

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Microplastic exposure disturbs sleep structure,reduces lifespan,and decreases ovary size in Drosophila melanogaster

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Zoological Research 2024年第4期45卷 805-820页

作者： Wei Yan zi-Jie li zi-Yi lin Shu-Qin Ji William Ka Fai Tse Zhi-qiang Meng Chang liu Lei li Shenzhen-Hong Kong Institute of Brain Science Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China CAS Key Laboratory of Brain Connectome and Manipulation the Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China Laboratory of Developmental Disorders and Toxicology Center for Promotion of International Education and ResearchFaculty of AgricultureKyushu UniversityFukuokaFukuoka 819-0395Japan Shenzhen Key Laboratory of Drug Addiction the Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China Guangdong Provincial Key Laboratory of Brain Connectome and Behavior Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China

The organ-specific toxicity resulting from microplastic(MP)exposure has been extensively explored,particularly concerning the gut,liver,testis,and ***,under natural conditions,these effects are not restricted to specific organs or *** whether MP exposure presents a systemic threat to an entire organism,impacting factors such as lifespan,sleep,and fecundity,is *** this study,we investigated the effects of dietary exposure to two different doses of MPs(1–5μm)using the terrestrial model organism Drosophila *** indicated that the particles caused gut damage and remained within the digestive *** MP exposure significantly shortened the lifespan of adult *** short-term exposure disrupted sleep patterns,increasing the length of daytime sleep ***,one week of MP exposure reduced ovary size,with a trend towards decreased egg-laying in mated *** MPs did not penetrate the brain or ovaries,transcriptome analysis revealed altered gene expression in these *** the ovary,Gene Ontology(GO)analysis indicated genotoxic effects impacting inflammation,circadian regulation,and metabolic processes,with significant impacts on extracellular structure-related *** the brain,GO analysis identified changes in pathways associated with proteolysis and carbohydrate ***,this study provides compelling evidence of the systemic negative effects of MP exposure,highlighting the urgent need to address and mitigate environmental MP pollution.

关键词： Microplastics Sleep lifespan Reproduction Risk assessment Drosophila melanogaster

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Effect of lanthanum on inclusions in non-oriented electrical steel slabs

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1680-1691页

作者： qiang Ren Zhi-yuan Hu Yun-xia liu Wei-cheng Zhang zi-qi Gao li-feng Zhang School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Research and Development Department Shougang Zhixin Qian'an Electromagnetic Material Co.Ltd.Qian'an 064400HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

The effect of lanthanum on the characteristics of inclusions in the slab of non-oriented electrical steels was investigated through industrial trials and thermodynamic *** number,size,and chemical composition of inclusions in the surface,one-quarter of thickness and the center of slabs with and without lanthanum addition were statistically analyzed using an automatic inclusion analysis *** the lanthanum-free slab,inclusions were predominately ***_(2)O_(3),MgO,and AlN as well as a small number of Al_(2)O_(3)-MgO-CaO and *** number densities of oxide inclusions and AlN decreased from the surface to the center of the slab,which was ascribed to the difference in cooling intensity during the continuous *** the steel with lanthanum addition,inclusions were modified into LaAlO_(3) and La_(2)O_(2)S and gradually transformed into dual-phase MgO-La_(2)S3 with an increasing distance from the slab surface due to the reaction between the lanthanum-containing inclusion and the steel *** uneven distribution of oxide inclusions along the thickness of the slab was eliminated in the lanthanum-bearing slab because the dissolved oxygen was remarkably decreased by ***-bearing inclusions were more likely to agglomerate AlN by inducing the heterogeneous nucleation of AlN on their surface,while small-size ***_(2)O_(3) inclusions hardly showed a coarsening effect on the size of AlN.

关键词： Lanthanum-Inclusion Non-oriented electrical steel Aluminum nitride Heterogenous nucleation

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One-pot and One-step Cu(0)-mediated Reversible-Deactivation Radical Polymerization of N-Isopropylacrylamide(NIPAM) in Water

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Chinese Journal of Polymer Science 2024年第1期42卷 1-6,I0004页

作者： zi-Shan li Jing Lyu Bei Qiu Ying-Hao li Ruth Foley Ri-Jian Song Melissa Johnson qiang Geng Wen-Xin Wang Institute of Precision Medicine(AUST-IPM) Anhui University of Science and TechnologyHuainan 232001China Charles Institute of Dermatology School of MedicineUniversity College DublinDublin D04 V1W8Ireland

Copper(0)-mediated reversible-deactivation radical polymerization(Cu(0)-mediated RDRP) of the water-soluble monomer Nisopropylacrylamide(NIPAM) has been challenging with the problems of high dispersity, poor control over the molecular weights(MWs) or complex or multi reaction steps, etc. In this work, we report the well-controlled polymerization of NIPAM in water via a facile one-pot and one-step Cu(0)-mediated RDRP. The results of this approach show that the key for kicking off the Cu(0)-mediated NIPAM RDRPs is to ensure sufficient Cu~I at the very beginning, and the key to achieve a well-controlled chain growth is to provide adequate deactivation strength during the polymerization process. For NIPAM, which has a high propagation rate constant, the deactivation control can be effectively enhanced by extra adding deactivator(i.e., Cu~II) to the system. Moreover, a low reaction temperature(4 ℃) is necessary in the controlled synthesis of higher MW poly(Nisopropylacrylamide)(PNIPAM) to avoid the compromise in control caused by the phase transition from its lower critical solution temperature(LCST). Through this new kinetically controlled strategy, PNIPAMs with well-defined structure, narrow molecular weight distributions(MWDs) and varied MWs were successfully achieved.

关键词： Cu(0)-mediated RDRP N-isopropylacrylamide Propagation Deactivation Reaction parameters

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Embeddings Among Quantum Affine sl_(n)

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Acta Mathematica Sinica,English Series 2024年第3期40卷 792-805页

作者： Yi qiang li Department of Mathematics University at BuffaloThe State University of New YorkBuffaloNY 14260USA

We establish an explicit embedding of a quantum affine sl_(n) into a quantum affine sl_(n)+*** embedding serves as a common generalization of two natural,but seemingly unrelated,embed-dings,one on the quantum affine Schur algebra level and the other on the non-quantum *** embedding on the quantum affine Schur algebras is used extensively in the analysis of canonical bases of quantum affine sln and gl_(n).The embedding on the non-quantum level is used crucially in a work of Riche and Williamson on the study of modular representation theory of general linear groups over a finite *** same embedding is also used in a work of Maksimau on the categorical representations of affine general linear *** further provide a more natural compatibility statement of the em-bedding on the idempotent version with that on the quantum affine Schur algebra level.A gl_(n)-variant of the embedding is also established.

关键词： Quantum affine sl_(n) embeddings

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Low temperature sintering and performance of aluminum nitride/borosilicate glass

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 109-113页

作者： Hong-sheng ZHAO Lei CHEN Nian-zi GAO Kai-hong ZHANG zi-qiang li Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

Aluminum nitride (AlN)/borosilicate glass composites were prepared by the tape casting process and hot-press sin-tered at 950°C with AlN and SiO2-B2O3-ZnO-Al2O3-li2O glass as starting *** characterized and analyzed the variation of the microstructure,bulk density,porosity,dielectric constant,thermal conductivity and thermal expansion coefficient (TEC) of the ceramic samples as a function of AlN *** show that AlN and SiO2-B2O3-ZnO-Al2O3-li2O glass can be sintered at 950°C,and ZnAl2O4 and Zn2SiO4 phase precipitated to form *** performance of the ceramic samples was de-termined by the composition and bulk density of the *** AlN content was found redounding to liquid phase sin-tering,and higher bulk density of composites can be accordingly *** the increase of porosity,corresponding decreases were located in the dielectric constant,thermal conductivity and TEC of the ceramic *** the mass fraction of AlN was 40%,the ceramic samples possessed a low dielectric constant (4.5～5.0),high thermal conductivity (11.6W/(m.K)) and a proper TEC (3.0×10-6K-1,which matched that of silicon).The excellent performance makes this kind of low temperature co-fired ce-ramic a promising candidate for application in the micro-electronics packaging industry.

关键词：硼硅酸盐玻璃氮化硼低温烧结技术

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Semi-supervised remote sensing image scene classification with prototype-based consistency

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Chinese Journal of Aeronautics 2024年第2期37卷 459-470页

作者： Yang li Zhang li zi WANG Kun WANG Qifeng YU College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Deep learning significantly improves the accuracy of remote sensing image scene classification,benefiting from the large-scale ***,annotating the remote sensing images is time-consuming and even tough for *** neural networks trained using a few labeled samples usually generalize less to new unseen *** this paper,we propose a semi-supervised approach for remote sensing image scene classification based on the prototype-based consistency,by exploring massive unlabeled *** this end,we,first,propose a feature enhancement module to extract discriminative *** is achieved by focusing the model on the foreground ***,the prototype-based classifier is introduced to the framework,which is used to acquire consistent feature *** conduct a series of experiments on NWPU-RESISC45 and Aerial Image Dataset(AID).Our method improves the State-Of-The-Art(SOTA)method on NWPU-RESISC45 from 92.03%to 93.08%and on AID from 94.25%to 95.24%in terms of accuracy.

关键词： Semi-supervised learning Remote sensing Scene classification Prototype network Deep learning

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