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Surface Quality Improvement in Machining an Aluminum Honeycomb by Ice Fixation

Chinese Journal of Mechanical Engineering 2020年第1期33卷 162-169页

作者： Yongqing Wang Yongquan Gan Haibo liu Lingsheng Han Jinyu Wang Kuo liu Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024China

A honeycomb structure is widely used in sandwich structure components in aeronautics and astronautics;however,machining is required to reveal some of its *** honeycomb structures,deficiencies,such as burrs,edge subsiding,and cracking,can easily appear,owing to poor specific sti ness in the radial *** e ective fixation methods based on a filling principle have been applied by researchers,including approaches based on wax,polyethylene glycol,iron powder,and(especially)***,few studies have addressed the optimization of the cutting *** study focused on optimizing the cutting parameters to obtain a better surface roughness(calculated as a roughness average or Ra)and surface morphology in the machining of an aluminum alloy honeycomb by an ice fixation method.A Taguchi method and an analysis of variance were used to analyze the e ects and contributions of spindle speed,cutting depth,and feed *** optimal cutting parameters were determined using the signal-to-noise ratio combined with the surface *** F-value and P-value were calculated for the value of the Ra,according to a"smaller is better"***,the optimum cutting parameters for machining the aluminum honeycomb by ice fixation were found at different *** results of this study showed that the optimal parameters were a feed rate of 50 mm/min,cutting depth of 1.2 mm,and spindle speed of 4000 r/*** rate was the most significant factor for minimizing Ra and improving the surface morphology,followed by spindle *** cutting depth had little e ect on Ra and surface *** optimization,the value of Ra could reach 0.218μm,and no surface morphology deterioration was observed in the verified ***,this research proposes optimal parameters based on ice fixation for improving the surface quality.

关键词： Honeycomb Ice fixation Cryogenic milling Surface roughness Surface morphology Optimal parameters

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Defective TiO_(2)-graphene heterostructures enabling in-situ electrocatalyst evolution for lithium-sulfur batteries

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Journal of Energy Chemistry 2021年第11期30卷 508-515,I0011页

作者： yanqi Feng Hui liu Yi liu Fuwei Zhao Junqi Li Xuanmeng He School of Materials Science and Engineering Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic MaterialsShaanxi University of Science and TechnologyXi’an 710021ShaanxiPR China

Lithium-sulfur (Li-S) batteries are considered as one of the promising next-generation energy storage systems because of their high energy density. While the low utilization of sulfur and sluggish reaction kinetics would lead to degradation of electrochemical performance and thus hinder the practical application of Li-S batteries. Herein, a double-shelled TiO_(2)-graphene heterostructure (H-TiO_(2)/rGO) with abundant oxygen vacancies (OVs) and highly exposed active plane as advanced host material in Li-S batteries is designed. This rational structure not only provides sufficient active sites and lower bandgap for lithium polysulfides (LiPSs), but also builds smooth adsorption-diffusion-conversion of LiPSs on catalyst, which greatly reduces interfacial energy barrier and promotes the utilization of sulfur through suppressing the devastating shuttling effect. Combining the synergetic merits of strong anchoring ability and catalyzing the of LiPSs, the electrode (S-TiO_(2)/rGO-1) exhibits superior rate performance and long lifespan (1000 cycles at 1C, 0.023% capacity loss per cycle) with high columbic efficiency. This work paves an alternative way to establish smooth adsorption-diffusion-conversion of polysulfides on catalyst in Li-S batteries and provides a new sight to understand catalyst design in energy storage devices.

关键词： Oxygen vacancy TiO_(2) Heterostructure Li-S batteries

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Phylogenetic analysis based on mitochondrial DNA sequences of wild rats, and the relationship with Seoul virus infection in Hubei, China

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Virologica Sinica 2017年第3期32卷 235-244页

作者： Dong-Ying liu Jing liu Bing-Yu liu Yuan-Yuan liu Hai-Rong Xiong Wei Hou Zhan-Qiu yang State Key Laboratory of Virology Institute of Medical Virology School of Basic Medical SciencesWuhan University Department of Microbiology School of Basic Medical Sciences Wuhan University School of Health Sciences Wuhan University

Seoul virus(SEOV), which is predominantly carried by Rattus norvegicus, is one of the major causes of hemorrhagic fever with renal syndrome(HFRS) in China. Hubei province, located in the central south of China, has experienced some of the most severe epidemics of HFRS. To investigate the mitochondrial DNA(mt DNA)-based phylogenetics of wild rats in Hubei, and the relationship with SEOV infection, 664 wild rats were captured from five trapping sites in Hubei from2000–2009 and 2014–2015. Using reverse-transcription(RT)-PCR, 41(6.17%) rats were found to be positive for SEOV infection. The SEOV-positive percentage in Yichang was significantly lower than that in other areas. The mt DNA D-loop and cytochrome b(cyt-b) genes of 103 rats were *** these animals, 37 were SEOV-positive. The reconstruction of the phylogenetic relationship(based on the complete D-loop and cyt-b sequences) allowed the rats to be categorized into two lineages, R. norvegicus and Rattus nitidus, with the former including the majority of the rats. For both the D-loop and cyt-b genes, 18 haplotypes were identified. The geographic distributions of the different haplotypes were significantly different. There were no significant differences in the SEOVpositive percentages between different haplotypes. There were three sub-lineages for the D-loop,and two for cyt-b. The SEOV-positive percentages for each of the sub-lineages did not significantly differ. This indicates that the SEOV-positive percentage is not related to the mt DNA D-loop or cyt-b haplotype or the sub-lineage of rats from Hubei.

关键词： Seoul virus(SEOV) Rattus norvegicus mitochondrial DNA phylogenetic analysis

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Effects of In-Medium Nucleon-Nucleon Cross Section and Nuclear Density Distribution on the Proton-Nucleus Total Reaction Cross Section

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Chinese Physics Letters 2013年第12期30卷 25-29页

作者： HAN Rui CHEN Zhi-Qiang R.Wada ZHANG Su-ya-La-Tu liu Xing-Quan LIN Wei-Ping JIN Zeng-Xue HU Bi-Tao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000 School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000 University of Chinese Academy of Sciences Beijing 100049

We present the proton-total reaction cross sectionsσR by comparing the experimental data with the Glauber model calculation using four sets of nucleon-nucleon cross sections used in literature(free nucleon-nucleon cross sections(NNCS),phenomenological NNCS,Bruckner-type NNCS and Pauli NNCS)and different nuclear densities for symmetric and asymmetric *** light symmetric target nuclei,the experimentalσR data are well reproduced by the former three NNCS with the ground state density distributions of relativistic mean-field *** the other hand,for asymmetry heavier target nuclei,the calculations of theσR data depend significantly on the nuclear density distribution at large radius in the low energy *** experimentalσR of these nuclei are well reproduced by the empirical 3 pF density distribution and the in-medium *** neutron surface distributions are also discussed based on the 3 pF nuclear charge distributions.

关键词： theory symmetric radius

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气候变化背景下1981-2010年中国玉米物候变化时空分异

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地理学报 2018年第5期73卷 906-916页

作者：秦雅刘玉洁葛全胜西安科技大学测绘科学与技术学院西安710054 中国科学院地理科学与资源研究所中国科学院陆地表层格局与模拟重点实验室北京100101

基于中国玉米种植区内114个农气站1981-2010年的长序列物候观测数据,量化分析了玉米8个连续物候期的时空分异特征和相应的生长阶段长度变化规律。结果表明:1981-2010年间,玉米生育期内平均温度和有效积温(GDD)呈现增加趋势,降水量和日... 详细信息

基于中国玉米种植区内114个农气站1981-2010年的长序列物候观测数据,量化分析了玉米8个连续物候期的时空分异特征和相应的生长阶段长度变化规律。结果表明:1981-2010年间,玉米生育期内平均温度和有效积温(GDD)呈现增加趋势,降水量和日照时数呈现减少趋势。气候变化背景下,玉米物候期发生了显著变化。春玉米物候期以提前趋势为主,包括西北内陆玉米区春玉米、西南山地丘陵玉米区春玉米;夏玉米和春夏播玉米各物候期在不同区域均呈现推迟的趋势,西北内陆玉米区夏玉米各物候期推迟的幅度大于黄淮平原夏玉米各物候期推迟的幅度。玉米物候期的变化改变了相应生长阶段的长度,中国春/夏/春夏播玉米营养生长期(播种期—抽雄期)呈现不同程度的缩短趋势,而对应的生殖生长期(抽雄期—成熟期)呈现不同程度的延长趋势;春玉米生育期(播种期—成熟期)延长,夏/春夏播玉米生育期缩短。

关键词：玉米物候气候变化时空分异中国

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Optimization of Fixture Number in Large Thin-Walled Parts Assembly Based on IPSO

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 213-227页

作者： Changhui liu Jing Wang Ying Zheng Ke Jin Jianbo Yu Jianfeng liu School of Mechanical Engineering Tongji UniversityShanghai 201804China Shanghai Jiaotong University Shanghai 200240China Shanghai Waigaoqiao Shipbuilding Co. Ltd.Shanghai 200137China

There are lots of researches on fixture layout optimization for large thin-walled *** researches focus on the positioning problem,i.e.,optimizing the positions of a constant number of ***,how to determine the number of fixtures is *** most cases,the number of fixtures located on large thin-walled parts is determined based on engineering experience,which leads to huge fixture number and extra ***,this paper constructs an optimization model to minimize the number of *** constraints are set in the optimization model to ensure that the part deformation is within the surface profile *** addition,the assembly gap between two parts is also *** conduct the optimization,this paper develops an improved particle swarm optimization(IPSO)algorithm by integrating the shrinkage factor and adaptive inertia *** the algorithm,particles are encoded according to the fixture *** dimension of the particle is assigned to a sub-region by constraining the optional position range of each fixture to improve the optimization ***,a case study on ship curved panel assembly is provided to prove that our method can optimize the number of fixtures while meeting the assembly quality *** research proposes a method to optimize the number of fixtures,which can reduce the number of fixtures and achieve deformation control at the same time.

关键词： Assembly quality Large thin-walled parts Fixture layout PSO FEM

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Natural forest ALS-TLS point cloud data registration without control points

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Journal of Forestry Research 2023年第3期34卷 809-820页

作者： Jianpeng Zhang Jinliang Wang Feng Cheng Weifeng Ma Qianwei liu Guangjie liu Faculty of Geography Yunnan Normal UniversityKunming 650500People’s Republic of China Key Laboratory of Resources and Environmental Remote Sensing for Universities in Yunnan Kunming 650500People’s Republic of China Center for Geospatial Information Engineering and Technology of Yunnan Province Kunming 650500People’s Republic of China College of Resources and Environment Yunnan Agriculture UniversityKunming 650201People’s Republic of China

Airborne laser scanning(ALS)and terrestrial laser scanning(TLS)has attracted attention due to their forest parameter investigation and research *** is limited to obtaining fi ne structure information below the forest canopy due to the occlusion of trees in natural *** contrast,TLS is unable to gather fi ne structure information about the upper *** address the problem of incomplete acquisition of natural forest point cloud data by ALS and TLS on a single platform,this study proposes data registration without control *** ALS and TLS original data were cropped according to sample plot size,and the ALS point cloud data was converted into relative coordinates with the center of the cropped data as the *** same feature point pairs of the ALS and TLS point cloud data were then selected to register the point cloud *** initial registered point cloud data was fi nely and optimally registered via the iterative closest point(ICP)*** results show that the proposed method achieved highprecision registration of ALS and TLS point cloud data from two natural forest plots of Pinus yunnanensis *** Picea asperata *** included diff erent species and *** average registration accuracy of 0.06 m and 0.09 m were obtained for *** and ***,respectively.

关键词： Airborne laser scanning(ALS) Terrestrial laser scanning(TLS) Registration Natural forest Iterative closest point(ICP)algorithm

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The profiles of chiral pesticides in peri-urban areas near yangtze River: Enantioselective distribution characteristics and correlations with surface sediments

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Journal of Environmental Sciences 2022年第11期34卷 199-210页

作者： Wenjun Zhang Tingting Li Jiayi Tang Xiaoli liu Yuhang liu Xiao Zhong Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education College of EnvironmentHohai UniversityNanjing 210098China

Chiral pesticides account for 30% of pesticides. Pesticides are inevitably leached into the groundwater by runoff. At the watershed level, the distribution characteristics of enantiomers in sediments collected from the river network of an agricultural area near the middle and lower reaches of the yangtze River were tested, and their potential correlations with the physicochemical properties and microbial communities of the sediments were analyzed. The sediment pollution was serious at sites 8 and 9, with their pollution source possibly being agricultural or industrial sewage. Moreover, there were higher cumulative contents of pesticide residues at sites 4, 8, and 9. Specifically, Cycloxaprid was the most detected chiral pesticide in the study area, followed by Dinotefuran and Diclofop-methyl. Additionally,Ethiprole and Difenoconazole had strong enantioselectivity in the study area. Interestingly,the enantiomers of some chiral pesticides, such as Tebuconazole, had completely different distributions at different sites. Pearson correlation analysis showed that sediment catalase and microbial biomass carbon were important factors for enantioselectivity of chiral pesticides. The effect of sediment physicochemical properties on enantioselective distribution was achieved by influencing the microorganisms in the sediment. Furthermore, the enantioselective distribution of Tebuconazole was closely related to the genus ***, the enantioselective distribution of most of the chiral pesticides was positively correlated with the prokaryotic microbial community. This study provides empirical support for agricultural non-point source pollution caused by chiral pesticides, and also lays a research foundation for exploring the factors that affect the fate of chiral pesticides in the environment.

关键词： Non-point source pollution Enantiomers Redundancy analysis Sediment enzymes Microbial community

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Precise measurement of geometric and physical quantities in cutting tools inspection and condition monitoring: A review

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Chinese Journal of Aeronautics 2024年第4期37卷 23-53页

作者： Wenqi WANG Wei liu yang ZHANG yang liu Peidong ZHANG Zhenyuan JIA State Key Laboratory of High-Performance Precision Manufacturing Dalian University of TechnologyDalian 116024China

As one of the most important terminals in machining, cutting tools have been widely used for components manufacturing in aerospace and other industries. The quality of these components and processing efficiency are closely linked to the performance of cutting tools. Therefore, it is essential and critical to inspect the cutting tools and monitor the condition during the stage of manufacturing and machining. This review aims to discuss and summarize the key problems, methods,and techniques from the perspective of the tool geometric and the physical quantities measurement,including machine vision, physical sensors and data processing. It is worth mentioning that we focus on the topic of precision measurement methods and discuss universal solutions by identifying the common characteristics of the measured quantities. Eventually, the challenges and future trends for the development of in-depth research and practical applications are concluded. The research and application of precise measurement techniques for geometric and physical quantities will better promote the development of intelligent manufacturing.

关键词： Cutting tools Mechanical measurement Machine vision Physical sensors Tool condition monitoring

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Harmonic balance-based approach for optimal time delay to control unstable periodic orbits of chaotic systems

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Acta Mechanica Sinica 2020年第4期36卷 918-925页

作者： Y.M.Chen Q.X.liu J.K.liu Department of Mechanics Sun Yat-sen UniversityGuangzhou 510275China

As a classical technique for chaos suppression,the time-delayed feedback controlling strategy has been widely developed by stabilizing unstable periodic orbits(UPOs)embedded in chaotic systems.A critical issue for achieving high controlling precision is to search for an appropriate time *** paper proposes a simple yet effective approach,based on incremental harmonic balance method,to determine the optimal time delay in the delayed feedback *** time delay is adjusted within the iterative scheme provided by the proposed method,and finally converges to the period of the target *** long as the optimal time delay is fixed,moreover,the attained solution makes it quite convenient to analyze its stability according to the Floquet theory,which further provides the effective interval of the feedback gain.

关键词： Chaos control Unstable periodic orbit Delayed feedback Optimal time delay Incremental harmonic balance method

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