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Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1319-1325页

作者： GUO xiaolu li Shuyue Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education Tongji UniversityShanghai 201804China School of Materials Science and Engineering Tongji UniversityShanghai 201804China

Tensile properties of fly ash based engineered geopolymer composites(FA-EGC)at different curing ages were studied by uniaxial tensile test and ultrasonic pulse velocity(UPV)methods,which included uniaxial tensile properties,the correlation between ultrasonic pulse velocity and tensile properties,and characteristic parameters of microcracks.The experimental results show that obvious strain hardening behavior can be found in FA-EGC at different curing ages.With the increase of curing age,the tensile strength increases,the tensile strain decreases and the toughness becomes worse.The UPV of FA-EGC increases with curing age,and a strong correlation can be found between tensile strength and UPV.With the increase of curing age,the average crack width of FA-EGC decreases and the total number of cracks increases.This is because the strength of geopolymer increases fast at early age,thus the later strength development of FA-EGC tend to be stable.At the same time,the bond strength between fiber and matrix,and the friction of fiber/matrix interface continue to increase with curing age,thus the bridging effect of fiber is gradually strengthened.In conclusion,the increase of curing age is beneficial to the development of tensile properties of FA-EGC.

关键词： engineered geopolymer composites(EGC) tensile properties ultrasonic pulse velocity(UPV) characteristic parameters of microcracks

Effect of nitrile butadiene rubber hardness on the sealing characteristics of hydraulic O-ring rod seals

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 63-78页

作者： Xiaoxuan li Bingqing WANG Xudong PENG Yuntang li Xiaolu Li Yuan CHEN Jie JIN College of Quality and Safety Engineering China Jiliang UniversityHangzhou310018China College of Mechanical and Electrical Engineering China Jiliang UniversityHangzhou310018China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou310023China

The nitrile butadiene rubber(NBR)hardness effect on the sealing characteristics of hydraulic O-ring rod seals is analyzed based on a mixed lubrication elastohydrodynamic model.Parameterized studies are conducted to reveal the mechanism of the influence of rubber hardness on the static and dynamic behavior of seals.The optimized selections of rubber hardness are then investigated under different conditions.Results show that the low hardness seal is prone to stress concentration due to the extrusion effect under high pressure conditions;it is also more prone to leaking.A high hardness seal can better prevent leakage by reducing film thickness but it will cause large frictional power loss and increase the probability of wear failure.The choice of low hardness is recommended to reduce friction with the premise that leakage requirements are met.

关键词： Nitrile butadiene rubber(NBR)hardness Sealing characteristics Optimized selection O-ring seal

Policy Iteration for Optimal Control of Discrete-Time Time-Varying Nonlinear Systems

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IEEE/CAA Journal of Automatica Sinica 2023年第3期10卷 781-791页

作者： Guangyu Zhu Xiaolu Li Ranran Sun Yiyuan Yang Peng Zhang Beijing Research Center of Urban Traffic Information Sensing and Service Technologies Key Laboratory of Transport Industry of Big Data Application Technologies for Comprehensive Transport Beijing Jiaotong UniversityBeijing 100044China Transport Planning and Research Institute Ministry of TransportChinaBeijing 100028China

Aimed at infinite horizon optimal control problems of discrete time-varying nonlinear systems,in this paper,a new iterative adaptive dynamic programming algorithm,which is the discrete-time time-varying policy iteration(DTTV)algorithm,is developed.The iterative control law is designed to update the iterative value function which approximates the index function of optimal performance.The admissibility of the iterative control law is analyzed.The results show that the iterative value function is non-increasingly convergent to the Bellman-equation optimal solution.To implement the algorithm,neural networks are employed and a new implementation structure is established,which avoids solving the generalized Bellman equation in each iteration.Finally,the optimal control laws for torsional pendulum and inverted pendulum systems are obtained by using the DTTV policy iteration algorithm,where the mass and pendulum bar length are permitted to be time-varying parameters.The effectiveness of the developed method is illustrated by numerical results and comparisons.

关键词： Adaptive critic designs adaptive dynamic programming approximate dynamic programming optimal control policy iteration time-varying

Early life history traits of chub mackerel Scomber japonicus in the Oyashio water revealed by otolith microstructure

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Journal of Oceanology and limnology 2023年第6期41卷 2444-2450页

作者： Xiaolu Li Chi ZHANG Yongjun TIAN Longshan liN Shigang liU Research Centre for Deep Sea and Polar Fisheries and Key Laboratory of MaricultureMinisty of EducationOcean University of ChinaQingdao 266100China Frontiers Science Center for Deep Ocean Multispheres and Earth System(FDOMES) Ocean University of ChinaQingdao 266100China Third Institute of Oceanography Ministry of Natural ResourcesXiamen 361000China

Information on survival and growth during the early life stage is essential to understand the mechanism of interannual variations in fish recruitment.Chub mackerel Scomber japonicus is a commercially important pelagic fish widely distributed in the northwestern Pacific.Its catch showed large fluctuations with changes in distribution and migration under climate change and strong fishing.We determined the hatch dates and growth rates of young-of-the-year of chub mackerel through otolith microstructure using samples collected in the Oyashio water in autumn 2018.Results show that the ages of young chub mackerel ranged between 120 and 180 d,and the estimated hatch date lasted from midJanuary to late May with a peak from mid-March to mid-April.Average otolith daily increment width during the early life stages(from hatching to 25 d)showed an increasing trend.Chub mackerel grows slowly in the first 10 d,and then grows faster during the 10thto 25thd.Three groups with dissimilar growth histories and migration routes were identified using unsupervised random forest clustering analysis,but all eventually converge on the same nursery ground.The faster growth of young-of-the-year chub mackerel leads to better recruitment due to the hypothesis of growth-dependent mortality.Most chub mackerels hatched in March and April,the spawning period is longer and earlier,which could lead to strong year classes.These findings on population composition and life history traits of young-of-the-year of chub mackerel provide valuable information on its recruitment processes during the period of stock recovery.

关键词： Scomber japonicus otolith microstructure growth history unsupervised random forest clustering recruitment

Exploring complex urban growth and land use efficiency in China's developed regions:implications for territorial spatial planning

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Frontiers of Earth Science 2022年第4期16卷 1040-1051页

作者： xiaolu TANG li SHENG Yinkang ZHOU School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Institute of Digital Agriculture Zhejiang Academy of Agricultural SciencesHangzhou 310021China

Developed regions in China have experienced rapid urban expansion and have consequently induced a series of challenging environmental issues since its economic reform and opening-up.Taking Zhejiang as a case study area,the present paper explores the complex types of urban growth over the last four decades as well as land use efficiency.Moreover,it discusses the implications of the aforementioned on China national territorial spatial planning(TSP).The acquired results have shown that:1)urban expansion has slowed down,exhibiting a three-stage trend of"slight increase(1980-1990)—dramatic growth(1990-2010)—slow growth(after 2010)";2)the complex types of urban growth reveal that the urban diffusion has been gradually controlled and the urban form tends to be more condensed;and 3)the mean values for pure technical efficiency(PTE)and scale efficiency(SE)of urban land use are 0.83 and 0.95 respectively,indicating PTE as the main factor restricting the improvement of urban land use.Based on these results,some beneficial policy implications and suggestions for TSP are provided.First,it is suggested that"Inventory Planning"will be the main direction of TSP other than"Incremental Planning".Secondly,we should pay more attention to the protection of cultivated land and ecological resources.Lastly,TSP should guide the economic growth away from simply relying on resource inputs and steer it toward technology and capital investment.

关键词： urban expansion urban growth types land use efficiency Zhejiang territorial spatial planning

Recent Advances on Early-Stage Fire-Warning Systems: Mechanism, Performance, and Perspective

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Nano-Micro Letters 2022年第12期14卷 106-136页

作者： Xiaolu Li Antonio Vazquez-Lopez Jose Sanchez del Rio Saez De-Yi Wang IMDEA Materials Institute C/Eric Kandel228906 GetafeMadridSpain E.T.S.de Ingenieros de Caminos Universidad Politecnica de MadridCalle Profesor Aranguren 328040 MadridSpain Departamento de Ingenieria Electrica Electronica Automatica y Fisica AplicadaETSIDIUniversidad Politecnica de MadridRonda de Valencia 328012 MadridSpain

Early-stage fire-warning systems(EFWSs)have attracted significant attention owing to their superiority in detecting fire situations occurring in the pre-combustion process.Substantial progress on EFWSs has been achieved recently,and they have presented a considerable possibility for more evacuation time to control constant unintentional fire hazards in our daily life.This review mainly makes a comprehensive summary of the current EFWSs,including the working mechanisms and their performance.According to the different working mechanisms,fire alarms can be classified into graphene oxide-based fire alarms,semiconductor-based fire alarms,thermoelectric-based fire alarms,and fire alarms on other working mechanisms.Finally,the challenge and prospect for EFWSs are briefly provided by comparing the art of state of fire alarms.This work can propose a more comprehensive understanding of EFWSs and a guideline for the cutting-edge development direction of EFWSs for readers.

关键词： Smart thermosensitive fire sensors Working mechanism Response time Signal conversion

Geographical Analysis of Community Resilience to Seismic Hazard in Southwest China

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International Journal of Disaster Risk Science 2016年第3期7卷 257-276页

作者： Xiaolu Li Lei Wang Shan liu School of Automation University of Electronic Science and Technology of China Department of Geography and Anthropology Louisiana State University

This article presents an explorative analysis of community resilience to seismic hazard in the 2008 Wenchuan Earthquake area of Southwest China. We used a regression model to analyze the impact of 13 key socioeconomic and demographic variables on community resilience in 105 counties, based on data derived from population census and provincial statistical yearbooks of China. In this research, we argue that community resilience should be measured by the change of population growth rate(Ddp) instead of population growth rate(dp) when using socioeconomic data from a fast-growing country such as China. Using Ddp as the dependent variable resulted in a better regression model. To avoid the common multicollinearity problems among the independent variables, a principal component-based factor analysis was used to consolidate the socioeconomic variables into four comprehensive factors. The geographically weighted regression coefficient maps revealed the spatial pattern of the association of the variables with resilience. We also used the K-means cluster method to segment the study area into four subregions that exhibit localized characteristics defined by the regression coefficients. In this way, we could infer location-sensitive disaster management policies that help to enhance social resilience to seismic hazards.

关键词： China Community resilience Geographic information system Geographically weighted regression Wenchuan Earthquake

Evolutionary dynamics of the severe acute respiratory syndrome coronavirus 2 genomes

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Medical Review 2022年第1期2卷 3-22页

作者： Zhaohui Qian Pei li xiaolu Tang Jian Lu Institute of Pathogen Biology Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100176China NHC Key Laboratory of Systems Biology of Pathogens Institute of Pathogen BiologyChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100871China State Key Laboratory of Protein and Plant Gene Research Center for BioinformaticsSchool of Life SciencesPeking UniversityBeijing100176China State Key Laboratory of Protein and Plant Gene Research Center for BioinformaticsSchool of Life SciencesPeking UniversityBeijing100871China

The coronavirus disease 2019(COVID-19)pandemic has caused immense losses in human lives and the global economy and posed significant challenges for global public health.As severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the causative agent of COVID-19,has evolved,thousands of single nucleotide variants(SNVs)have been identified across the viral genome.The roles of individual SNVs in the zoonotic origin,evolution,and transmission of SARS-CoV-2 have become the focus of many studies.This review summarizes recent comparative genomic analyses of SARS-CoV-2 and related coronaviruses(SC2r-CoVs)found in non-human animals,including delineation of SARS-CoV-2 lineages based on characteristic SNVs.We also discuss the current understanding of receptor-binding domain(RBD)evolution and characteristic mutations in variants of concern(VOCs)of SARS-CoV-2,as well as possible co-evolution between RBD and its receptor,angiotensin-converting enzyme 2(ACE2).We propose that the interplay between SARS-CoV-2 and host RNA editing mechanisms might have partially resulted in the bias in nucleotide changes during SARS-CoV-2 evolution.Finally,we outline some current challenges,including difficulty in deciphering the complicated relationship between viral pathogenicity and infectivity of different variants,and monitoring transmission of SARS-CoV-2 between humans and animals as the pandemic progresses.

关键词： molecular evolution population genetics severe acute respiratory syndrome coronavirus 2 variant virus.

Comparison of 2-acetylfuran,2-ethylfuran,and 2-methylfuran spherically expanding flame intrinsic instabilities

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Science China(Technological Sciences) 2022年第10期65卷 2388-2398页

作者： XU CangSu WANG QianWen li xiaolu OPPONG Francis liU WeiNan College of Energy Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027China College of Mechanical and Electrical Engineering Key Laboratory of Intelligent Manufacturing Quality Big Data Tracing and Analysis of Zhejiang ProvinceChina Jiliang UniversityHangzhou 310018China

The intrinsic instability of three furan derivatives, namely, 2-acetylfuran(AF), 2-ethylfuran(EF), and 2-methylfuran(MF), is experimentally and theoretically investigated and compared. A deep-learning-based end-to-end system is used to segment the cells and measure the crack length on the cellular flame front of the spherically expanding flame to quantitively investigate the flame morphology. Moreover, the flame front radius profile is quantitively investigated to shed light on the correlation between disturbance amplitude and flame radius. With the use of the linear stability model, the theoretical critical flame radius and Peclet number are obtained and compared to their corresponding experimental results to characterize the outset of cellularization and evaluate the flame instability propensity. Our analysis shows that compared with AF and EF, MF is prone to cellularization at a smaller flame radius and has a faster cell proliferation rate and crack length growth rate before reaching the hydrodynamic saturation limit. Meanwhile, the average area of saturated cells tends to be similar for the three furan derivatives. Furthermore,AF premixed flame does not exhibit cellularization before the flame radius is less than 45 mm in low initial pressure.

关键词： furan derivatives spherical expanding flame flame intrinsic instability linear stability theory

A Neural Circuit Controlling Virgin Female Aggression Induced by Mating-related Cues in Drosophila

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Neuroscience Bulletin 2023年第9期39卷 1396-1410页

作者： xiaolu Wan Peng Shen Kai Shi Jing li Fengming Wu Chuan Zhou State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijing100101China University of Chinese Academy of Sciences Beijing100049China Institute of Molecular Physiology Shenzhen Bay LaboratoryShenzhen518132China

Females increase aggression for mating opportunities and for acquiring reproductive resources.Although the close relationship between female aggression and mating status is widely appreciated,whether and how female aggression is regulated by mating-related cues remains poorly understood.Here we report an interesting observation that Drosophila virgin females initiate high-frequency attacks toward mated females.We identify 11-cis-vaccenyl acetate(cVA),a male-derived pheromone transferred to females during mating,which promotes virgin female aggression.We subsequently reveal a cVA-responsive neural circuit consisting of four orders of neurons,including Or67d,DA1,aSP-g,and pC1 neurons,that mediate cVA-induced virgin female aggression.We also determine that aSP-g neurons release acetylcholine(ACh)to excite pC1 neurons via the nicotinic ACh receptor nAChRα7.Together,beyond revealing cVA as a mating-related inducer of virgin female aggression,our results identify a neural circuit linking the chemosensory perception of mating-related cues to aggressive behavior in Drosophila females.

关键词： Drosophila Aggression Pheromone 11-cis-vaccenyl acetate Acetylcholine Neural circuit