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New method to identify optimal discontinuity set number of rock tunnel excavation face orientation based on Fisher mixed evaluation

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Underground Space 2024年第4期17卷 300-319页

作者： Keshen Zhang Wei Wu Min Zhang yongsheng liu yong Huang Baolin Chen College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shudao Investment Group Co.Ltd Chengdu 610095China China Railway Tunnel Group Co.Ltd Guangzhou 511466China China Railway First Survey and Design Institute Group Co.Ltd Xi’an 710043China Zhejiang Institute of Communications Co.Ltd Hangzhou 310012China

Discontinuity is critical for strength,deformability,and permeability of rock *** information is one of the essential discontinuity characteristics and is usually accessed by orientation *** methods of identifying optimal discontinuity set numbers are usually achieved by clustering validity indexes,which mainly relies on the aggregation and dispersion of clusters and leads to the inaccuracy and instability of *** paper proposes a new method of Fisher mixed evaluation(FME)to identify optimal group numbers of rock mass discontinuity *** FME,orientation distribution is regarded as the superposition of Fisher mixed *** grouping results are identified by considering the fitting accuracy of Fisher mixed distributions,the probability monopoly and central location significance of independent Fisher centers.A Halley-Expectation-Maximization(EM)algorithm is derived to achieve an automatic fitting of Fisher mixed *** real rock discontinuity models combined with three orientation clustering algorithms are adopted for discontinuity *** clustering validity indexes are used to automatically identify optimal group numbers for *** results show that FME is more accurate and robust than the other clustering validity indexes in optimal discontinuity group number identification for different rock models and orientation clustering algorithms.

关键词： Rock mass discontinuity Orientation grouping Fisher mixed distribution 3D point cloud Stereo photogrammetry

尺寸可控的单分散四氧化三铁微球的省时制备（英文）

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物理化学学报 2017年第11期33卷 2310-2316页

作者：王丹刘传勇龙玥宋恺黄维南京邮电大学先进生物与化学制造协同创新中心有机电子与信息显示国家重点实验室培育基地南京210023 中国科学院化学研究所北京100190 中国科学院理化技术研究所北京100190

用溶剂热法制备了单分散性较好、尺寸可控,饱和磁化强度高的四氧化三铁磁性微球,并用多种手段调控制备了不同尺寸和形貌的四氧化三铁微球,如氯化铁、醋酸钠、水的量以及反应时间。结果表明所得四氧化三铁产物纯净、结晶度高,形状近乎球... 详细信息

用溶剂热法制备了单分散性较好、尺寸可控,饱和磁化强度高的四氧化三铁磁性微球,并用多种手段调控制备了不同尺寸和形貌的四氧化三铁微球,如氯化铁、醋酸钠、水的量以及反应时间。结果表明所得四氧化三铁产物纯净、结晶度高,形状近乎球形、无团聚,大小均一、具有很好的单分散性。此方法可以在2-4 h内制备400-700 nm范围内尺寸可控、高饱和磁化强度的四氧化三铁微球,产率达到了94%。

关键词：单分散四氧化三铁微球溶剂热法省时可控

Enantioselective Synthesis of Benzimidazole Atropisomers Featuring a N-N Axis

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Chinese Journal of Chemistry 2024年第7期42卷 711-718页

作者： Fang-Bei Ge Qi-Kun Yin chuan-Jun Lu Xuan Xuan Jia Feng Ren-Rong liu College of Chemistry and Chemical Engineering Qingdao UniversityQingdaoShandong 266071China School of Pharmacy Key Laboratory of Molecular Pharmacology and Drug EvaluationMinistry of EducationYantai UniversityYantaiShandong 264005China

Atroposelective synthesis of N-N atropisomers is an emerging area but remains underexplored;in particular,the synthesis of N-N benzimidazole atropisomers is still ***,the first enantioselective synthesis of N-N benzimidazole atropisomers via the palladium-catalyzed de novo construction of benzimidazole skeleton is *** readily available palladium catalyst and biphosphine ligand,a broad range of nonbiaryl benzimidazole and indole-benzimidazole atropisomers were conveniently ac-cessed in high yields and with excellent ***,these N-N benzimidazole atropisomers showed great anti-tumor activity and selectivity to breast cancer MCF-7 *** simple catalytic system,broad substrate scope,high enantioselectivi-ty,and good bioactivity make this approach highly attractive.

关键词： Asymmetric synthesis Atropisomerism Palladium Benzimidazole Antitumor

Highly efficient capture of thorium ion by citric acid-modified chitosan gels from aqueous solution

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Chinese Chemical Letters 2024年第5期35卷 361-365页

作者： Linshan Peng Qihang Peng Tianxiang Jin Zhirong liu yong Qian State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices East China University of TechnologyNanchang 330013China

A novel citric acid-modified chitosan gel(CSCA)was synthesized through a simple one-step process and was used to extract thorium ions from *** CSCA samples with varying chemical compositions were analyzed using SEM with mapping EDS,FT-IR,and static water contact angle measurements,and their adsorption behaviors were studied in *** results showed that the adsorption performance of CSCA improves with the increase of CA content in the *** possesses an impressive capacity for thorium adsorption of 279.8 mg/***,it showed an ultra-fast adsorption rate and reached equilibrium within 30 *** terms of recyclability,the CSCA still retained more than 86%of its initial adsorption capacity after 6 cycles of *** functional theory(DFT)analysis reveals that the good selectivity of this material towards thorium ions should be attributed to the high density of adsorption sites and strong interaction between carboxyl groups and thorium *** work could be beneficial in the design and synthesis of new polymer materials for extracting thorium.

关键词： Thorium Adsorption Citric acid Chitosan DFT calculation

Numerical Simulation on Radon Retardation Behavior of Covering Floats in Radon-Containing Water

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Biomedical and Environmental Sciences 2024年第4期37卷 406-417页

作者： liu Shu Yuan ZHANG Li YE yong Jun DING Ku Ke National Institute for Radiological Protection Chinese Center for Disease Control and PreventionBeijing 100088China Office for Public Health Management Chinese Center for Disease Control and PreventionBeijing 102206China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001HunanChina

Objective This study aimed to efficiently reduce the release of radon from water bodies to protect the *** Based on the sizes of the experimental setup and modular float,computational fluid dynamics(CFD)was used to assess the impact of the area coverage rate,immersion depth,diffusion coefficient,and radon transfer velocity at the gas–liquid interface on radon migration and exhalation of radon-containing *** on the numerical simulation results,an estimation model for the radon retardation rate was *** effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area *** The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value;therefore,an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors:area coverage rate,immersion depth,and diffusion *** deviation between the experimental and simulated results was<4.3%.Conclusion Based on the numerical simulation conditions,an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained,which provides a reference for designing covering floats for radon retardation in radoncontaining water.

关键词： Radon-containing water Radon retardation rate CFD Coverage experiment Optimized design

Numerical design of an efficient Ho^(3+)-doped InF3 fiber laser at~3.2μm

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Journal of Electronic Science and Technology 2024年第3期22卷 35-46页

作者： Shi-Yuan Zhou Hong-Yu Luo Ya-Zhou Wang yong liu State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of ChinaChengdu611731China DTU Electro Technical University of DenmarkKongens Lyngby2800Denmark

In this work,we theoretically unlock the potential of Ho^(3+)-doped InF3 fiber for efficient~3.2μm laser generation(from the 5F4,5S2→5F5 transition),by employing a novel dual-wavelength pumping scheme at 1150 nm and 980 nm,for the first *** clad-coupled 1150 nm pumping of 5 W,~3.2μm power of 3.6 W has been predicted with the optical-to-optical efficiency of 14.4%.Further efficient power scaling,however,is blocked by the output saturation with 980 nm *** alleviate this behavior,the cascaded 5I5→5I6 transition,targeting~3.9μm,has been activated simultaneously,therefore accelerating the population circulation between the laser upper level 5F4,5S2 and long-lived 5I6 level under 980 nm *** a result,enhanced~3.2μm power of 4.68 W has been obtained with optical-to-optical efficiency of 15.6%.Meanwhile the~3.9μm laser,yielding power of 2.76 W with optical-to-optical efficiency of 9.2%,is theoretically achievable as well with a moderate heat load,of which the performance is even better than the prior experimentally and theoretically reported Ho^(3+)-doped InF3 fiber lasers emitting at~3.9μm *** work demonstrates a versatile platform for laser generation at~3.2μm and~3.9μm,thus providing the new opportunities for many potential applications,e.g.,polymer processing,infrared countermeasures,and free-space communications.

关键词： Cascaded Fiber laser Holmium Mid-infrared

Autonomous trajectory tracking control method for an agricultural robotic vehicle

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 215-224页

作者： Jin Yan Wenguang Zhang yong liu Wei Pan Xiaoyu Hou Zhiyu liu School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Information Engineering Xuzhou University of TechnologyXuzhou 221018JiangsuChina National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

To address the nonlinearities and external disturbances in unstructured and complex agricultural environments,this paper investigates an autonomous trajectory tracking control method for agricultural ground ***,this paper presents the design and implementation of a lightweight,modular two-wheeled differential drive vehicle equipped with two drive wheels and two caster *** vehicle comprises drive wheel modules,passive wheel modules,battery modules,a vehicle frame,a sensor system,and a control ***,a novel robust trajectory tracking method was proposed,utilizing an improved pure pursuit ***,an Online Particle Swarm Optimization Continuously Tuned PID(OPSO-CTPID)controller was introduced to dynamically search for optimal control gains for the PID *** results demonstrate the superiority of the improved pure pursuit algorithm and the OPSO-CTPID control *** validate the performance,the vehicle was integrated with a seeding and fertilizing machine to realize autonomous wheat seeding in an agricultural *** outcomes reveal that the vehicle of this study completed a seeding operation exceeding 1 km in *** proposed method can robustly and smoothly track the desired trajectory with an accuracy of less than 10 cm for the root mean square error(RMSE)of the curve and straight lines,given a suitable set of parameters,meeting the requirements of agricultural *** findings of this study hold significant reference value for subsequent research on trajectory tracking algorithms for ground-based agricultural robots.

关键词： trajectory tracking autonomy control agricultural robotic vehicle online PSO continuously tuned PID dynamic pure pursuit algorithm

Synthesis of highly stable Ni nanoparticles via electrostatic self-assembly for enhanced hydrogen storage of MgH_(2)

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Rare Metals 2024年第9期43卷 4356-4366页

作者： Qin-Ke Tang Jiang-chuan liu Rui Shi Yun-Feng Zhu Ji-Guang Zhang Ya-Na liu Jun Wang Yao Zhang Xiao-Hui Hu Zhi-Bin liu Li-Quan Li College of Materials Science and Engineering Jiangsu Collaborative Innovation Centre for Advanced Inorganic Function CompositesNanjing Tech UniversityNanjing 211816China School of Materials Science and Engineering Southeast UniversityNanjing 211189China

Magnesium-based hydrides have been widely recognized as an appropriate choice for solid-state hydrogen ***,its undesirable thermodynamics and sluggish hydrogenation/dehydrogenation kinetics are major bottlenecks for its ***,a highly stable and highly dispersed Ni-based catalyst(Ni/Al_(2)O_(3)/GN)was fabricated to promote the hydrogen storage performance of MgH_(2)via the electrostatic effect of NiAl-LDH/GN precursor with a co-calcination reduction ***_(2)-5wt%Ni/Al_(2)O_(3)/GN exhibits excellent hydrogen storage performance,releasing about 5.7 wt%hydrogen in 3500 s at 250℃,and can reach a saturation hydrogen absorption of about 6.15 wt%in 3000 s at 100℃.Furthermore,it also shows low dehydrogenation apparent activation energy of 89.1 and 118.2 kJ·mol^(-1).Impressively,the catalyst ensures the stability of both the physical phase and structure during ball milling and cycling *** role of each phase in Ni/Al_(2)O_(3)/GN on the hydrogen storage performance of MgH_(2)was also discussed through experiments and theoretical calculation,and the synergistic catalytic mechanism of Ni/Al_(2)O_(3)/GN was clearly *** work provides a unique perspective for the preparation of highly stable and highly dispersible catalysts.

关键词： Magnesium hydride Ni/Al_(2)O_(3)/GN Hydrogen storage performance Catalytic mechanism

Single-Component Color-Tunable Smart Organic Emitters with Simultaneous Multistage Stimuli-Responsiveness and Multimode Emissions

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Research 2024年第2期2023卷 719-728页

作者： Yu Yan Chengfang liu Jianzhong Fan Yusheng Li Huanling liu Qian Wang Xiangchun Lil Junfeng Li Wen-yong Lai State Key Laboratory of Organic Electronics and Information Displays(SKLOEID) Institute of Advanced Materials(IAM)School of Chemistry and Life SciencesNanjing University of Posts&Telecommunications9 Wenyuan RoadNanjng 210023China Shandong Province Key Laboratory of Medical Physics and Image Processing Technology School of Physics and ElectronicsShandong Normal UniversityJinan 250358China

Achieving color-tunable emission in single-component organic emitters with multistage stimuli-responsiveness is of vital significance for intelligent optoelectronic applications,but remains enormously ***,we present an unprecedented example of a color-tunable single-component smart organic emitter(DDOP)that simultaneously exhibits multistage stimuli-responsiveness and multimode *** based on a highly twisted amide-bridged donor-tcceptor-donor structure has been found to facilitate intersystem crossing,form multimode emissions,and generate multiple emissive species with multistage *** pristine crystalline powders exhibit abnormal excitation-dependent emissions from a monomer-dominated blue emission centered at 470 nm to a dimer-dominated yellow emission centered at 550 nm through decreasing the ultraviolet(UV)excitation wavelengths,whereas DDOP single crystals show a wide emission band with a main emission peak at 585 nm when excited at different *** emission behaviors of pristine crystalline powders and single crystals are different,demonstrating emission features that are closely related to the aggregation *** work has developed color-tunable single-component organic emitters with simultaneous multistage stimuli-responsiveness and multimode emissions,which is vital for expanding intelligent optoelectronic applications,including multilevel information encryption,multicolor emissive patterns,and visual monitoring of UV wavelengths.

关键词： donor excitation Smart