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Experimental study of rotating gliding arc discharge plasma-assisted combustion in an aero-engine combustion chamber

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Chinese Journal of Aeronautics 2019年第2期32卷 337-346页

作者： liming HE Yi CHEN Jun DENG jianping LEI li FEI Pengfei liU Science and Technology on Plasma Dynamics Laboratory Aeronautics and Astronautics Engineering CollegeAir Force Engineering University

The combustion chamber is the core component of an aero-engine, and affects its reliability and security operation, even the performance of the aircraft. In this work, a Plasma-Assisted Combustion(PAC) test platform was developed to validate the feasibility of using PAC actuators to enhance annular combustor performance. Two plans of PAC(rotating gliding arc discharge plasma) were designed, Assisted Combustion from Primary Holes(ACPH) and Assisted Combustion from Dilution Holes(ACDH). Comparative experiments and analysis between conventional combustion and PAC were conducted to study the effects of ACPH and ACDH on the performances including average outlet temperature, combustion efficiency, pattern factor under four different excessive air coefficients(0.8, 1, 2, and 4), and lean blowout performance at different inlet airflow velocities. Experimental results show that the combustion efficiency is improved after PAC compared with that in normal conditions, and the combustion efficiency of ACPH increases2.45%, 1.49%, 1.04%, and 0.47%, while it increases 2.75%, 1.67%, 1.36%, and 0.36% under ACDH conditions. The uniformity of the outlet temperature field and the lean blowout performance are improved after PAC. Especially for ACPH, the widening of the lean blowout limit is8.3%, 12.4%, 12.8%, and 25% respectively when the inlet velocity ranges from 60 m/s to120 m/s. These results offer new perspectives for using PAC devices to enhance aero-engine combustors' performances.

关键词： Aero-engine Assisted combustion actuator Combustion chambers Plasma-Assisted Combustion Rotating gliding arc discharge

Insights into Pyrolysis of Nano-Polystyrene Particles: Thermochemical Behaviors and Kinetics Analysis

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Journal of Thermal Science 2019年第4期28卷 763-771页

作者： DING li ZHAO jianping PAN Yong GUAN Jin JIANG Juncheng WANG Qingsheng College of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China College of Safety Science and Engineering Nanjing Tech UniversityNanjing 211816China Department of Fire Protection and Safety Oklahoma State UniversityStillwater 74078USA

The thermal degradation kinetics of nano-polystyrene particles with diameters of 60,90,160,and 225 nm were investigated in nitrogen atmosphere using thermogravimetric analysis(TGA).Various kinetic models were employed to determine the thermal degradation mechanism and ***-polystyrene particles have relatively lower thermal stability when compared to *** differential thermo–gravimetric(DTG)data and apparent activation energies indicate that the thermal degradation of nano-polystyrene particles at 60 nm is a two-step reaction process where the second step plays a dominant role,while nano-polystyrene particles with diameter greater than 60 nm exhibit single-step *** to most micro/macro polystyrene particles,DTG peaks of nano-polystyrene particles shift towards higher temperatures with increasing heating *** degradation of nano-polystyrene particles under nitrogen atmosphere follows the first-order reaction ***,the apparent activation energies increase(162-181 kJ·mol–1)with the increase of particle sizes(60-225 nm).This study could provide some insights into pyrolysis of nano-polystyrene particles and a safer process of manufacturing,storage and handling of nano-polystyrene particles.

关键词： nano-polystyrene thermal decomposition kinetics mechanism

Study of risk acceptance criteria for dams

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Science China(Technological Sciences) 2015年第7期58卷 1263-1271页

作者： li ShouYi ZHOU XingBo WANG YuJie ZHOU jianping DU XiaoHu CHEN ZuYu Institute of Water Resources and Hydropower Engineering Xi'an University of Technology Department of Geotechnical Engineering China Institute of Water Resources and Hydropower Research Power Construction Corporation of China Ltd. China Renewable Energy Engineering Institute

This paper discusses the methods of establishing risk criteria for dams and reviews the application of dam risk criteria for individuals and societies in different countries or districts. Given the conditions in China and considering the public safety and acceptance of dam risk, historical dam break data and current design standards, individual and societal risk criteria for dams are proposed. The tolerable dam risk criteria for individuals should be set to 10-5-10-7 per annum based on project scale, for ex- ample, approximately 1.0xl0 7 per annum, which corresponds to a reliability index of 4.2 based on a 100-year lifespan for a first-class or large project. The societal limit for risk tolerance for dams should be set to approximately 10-3-10-5 per annum, corresponding to the fatality range from 1 to 100 and be horizontally extended to 1000, and F-N curves are proposed. It was also found that the reliability indices of Chinese Standard （GB 50199-2013） and Eurocodel （2002） are different, but they have the same level of safety measured by the annual probability of failure. The research results have significance for establishing dam risk criteria.

关键词： dam risk criteria acceptable risk annual probability of failure dam safety

Multi‑color Tunable and White Circularly Polarized Luminescent Composite Nanofibers Electrospun from Chiral Helical Polymer

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Advanced Fiber Materials 2022年第6期4卷 1632-1644页

作者： Pengpeng li Xiaobin Gao Biao Zhao Kai Pan jianping Deng State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical Technology100029 BeijingChina College of Materials Science and Engineering Beijing University of Chemical Technology100029 BeijingChina

Circularly polarized luminescence(CPL)-active nanomaterials have attracted tremendous ***,it is still a big challenge to conveniently fabricate multi-color and white CPL-active nanomaterials on a large ***,a simple and scalable approach to achieve the above goals is *** CPL-active nanofibers are fabricated from chiral helical substituted polyacetylene,achiral fluorescent dyes and polyacrylonitrile via uniaxial electrospinning;the highest luminescence dissymmetry factor(glum)of the resulting nanofibers can reach 10^(−2).Furthermore,white CPL-active nanofibers are obtained by coaxial electrospinning,in which the resulting core-shell structure has excellent adjustability and can be utilized to physically isolate different fluorescent dyes to reduce energy transfer efficiency;therefore,stable white CPL emissions can be achieved with high g_(lum) values up to 10^(−3).Notably,the prepared white-emission CPL nanofibrous films show bright white circularly polarized light when coated on UV chips,demonstrating their future application in constructing low-cost and flexible light-emitting devices such as circularly polarized light-emitting diodes.

关键词： Chiral helical polymer Nanofiber Multi-color circularly polarized luminescence White-light emission

Dense 3D surface reconstruction of large-scale streetscape from vehicle-borne imagery and liDAR

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International Journal of Digital Earth 2021年第5期14卷 619-639页

作者： Xiaohu lin Bisheng Yang Fuhong Wang jianping li Xiqi Wang School of Geodesy and Geomatics Wuhan UniversityWuhanPeople’s Republic of China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanPeople’s Republic of China School of Remote Sensing Information Engineering Wuhan UniversityWuhanPeople’s Republic of China

Accurate and efficient three-dimensional(3D)streetscape reconstruction is the fundamental ability for an exploration vehicle to navigate safely and perform high-level ***,remarkable progress has been made in streetscape reconstruction with visual images and light detection and ranging(liDAR),but they have difficulties either in scaling and reconstructing large-scale outdoors or in efficient *** address these issues,this paper proposed an automatic method for incremental dense reconstruction of large-scale 3D streetscapes from coarse to fine at near real ***,the pose of vehicle is estimated by visual and laser odometry(VLO)and the state-of-the-art pyramid stereo matching network(PSMNet)is introduced to estimate depth ***,incremental dense 3D streetscape reconstruction is conducted by key-frame selection and coarse registration with local ***,redundant and noise points are removed through multiple filtering,resulting good quality of dense *** experiments were undertaken to check the visual effect,trajectory pose error and multi-scale model to model cloud comparison(M3C2)based on reference trajectories and reconstructions provided by the state-of-the-art method,showing the precision,recall and F-score of sampling core points(SCPs)are over 80.42%,71.68%and 77.19%,respectively,which verified the proposed method.

关键词： Dense 3D streetscape reconstruction vehicleborne imagery stereo matching pose estimation multiple filtering

Can communications and sensors work together in one network?

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Frontiers of Optoelectronics 2009年第2期2卷 148-152页

作者： Xinwan li jianping CHEN State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University

With the development of both optical fiberbased communication and sensation, one interesting topic has been pointed out. How to connect those mountains of sensors to detect the signal in a large area, and how to make the cost of sensing system lower enough should be studied.A network of sensors is a good option. All sensing equipments, including the interrogators and the sensors,will be internetworking together. However, fiber optic communication networks have been developed very well over the past two decades. Is it necessary to rebuild a new network for sensors? In this paper, some new technologies in the two areas of fiber optic sensors and fiber optic communication will be addressed. Then, the available overlay architecture of a fiber optic sensors network will be presented. Finally, a polymorphous optical burst switching(POBS)-based architecture will be proposed, which can support all kinds of services, including digital data optical circuit/burst/packet switching and analog fiber optic sensor signal circuit/burst switching, etc.

关键词： optical sensor network optical communication network polymorphous optical burst switching (POBS) optical circuit switching (OCS) optical burst switching (OBS)

Compound events of heatwave and dust storm in the Taklamakan Desert

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Science China Earth Sciences 2024年第7期67卷 2073-2083页

作者： Yuzhi liU jianping HUANG Ziyuan TAN Chenglong ZHOU Dan li Yongkun XIE Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou UniversityLanzhou 730000China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China Taklamakan National Station of Observation and Research for Desert Meteorology in Xinjiang Urumqi 830002China

Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global ***,the association between heatwaves and dust storms is poorly *** this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the *** results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),*** than 40% of heatwaves existed with dust events,which significantly lagged behind ***,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the *** high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD *** anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by *** climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.

关键词： Heatwave Dust storm Compound events Taklamakan Desert

Impact of Perturbation Schemes on the Ensemble Prediction in a Coupled Lorenz Model

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Advances in Atmospheric Sciences 2023年第3期40卷 501-513页

作者： Qian ZOU Quanjia ZHONG Jiangyu MAO Ruiqiang DING Deyu LU jianping li Xuan li State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Frontiers Science Center for Deep Ocean Multispheres and Earth System(FDOMES)/Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies Ocean University of ChinaQingdao 266100China Laboratory for Ocean Dynamics and Climate Pilot Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China

Based on a simple coupled Lorenz model,we investigate how to assess a suitable initial perturbation scheme for ensemble forecasting in a multiscale system involving slow dynamics and fast *** initial perturbation approaches are used in the ensemble forecasting experiments:the random perturbation(RP),the bred vector(BV),the ensemble transform Kalman filter(ETKF),and the nonlinear local Lyapunov vector(NLLV)*** show that,regardless of the method used,the ensemble averages behave indistinguishably from the control forecasts during the first few time *** to different error growth in different time-scale systems,the ensemble averages perform better than the control forecast after very short lead times in a fast subsystem but after a relatively long period of time in a slow *** to the coupled dynamic processes,the addition of perturbations to fast variables or to slow variables can contribute to an improvement in the forecasting skill for fast variables and slow *** the initial perturbation approaches,the NLLVs show higher forecasting skill than the BVs or RPs *** NLLVs and ETKFs had nearly equivalent prediction skill,but NLLVs performed best by a narrow *** particular,when adding perturbations to slow variables,the independent perturbations(NLLVs and ETKFs)perform much better in ensemble *** results are simply implied in a real coupled air–sea *** the prediction of oceanic variables,using independent perturbations(NLLVs)and adding perturbations to oceanic variables are expected to result in better performance in the ensemble prediction.

关键词： ensemble prediction nonlinear local Lyapunov vector(NLLV) ensemble transform Kalman filter(ETKF) coupled air-sea models

Cretaceous source to sink system reconstruction of northeastern Asian continental margin:Insight from integrated detrital geochronology in NE China

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Geoscience Frontiers 2023年第5期14卷 213-232页

作者： jianping Zhou István Dunkl Yongjiang liu Sanzhong li Weimin li Hilmar von Eynatten University of Göttingen Geoscience CenterDepartment of Sedimentology and Environmental GeologyGoldschmidtstrasse 3Göttingen D-37077Germany Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Lab of Submarine Geosciences and Prospecting Techniquesand College of Marine GeosciencesOcean University of ChinaQingdao 266100China Laboratory for Marine Mineral Resources Laoshan LaboratoryQingdao 266100China College of Earth Sciences Jilin UniversityJianshe Str.2199Changchun 130061China

The Cretaceous sedimentary successions in NE China are largely incomplete as the basins are inverted and younger strata are *** for the Songliao Basin,whose depositional record has remained relatively intact,the burial record to the east was interrupted in the late Early or Late *** is still controversy on the possible connection between the Songliao Basin and the eastern basin group,as well as the extent of the previously suggested“pan-Sanjiang”proto-basin that covered most current eastern satellite *** address these questions,we studied modern river catchments of variable sizes from sediment-supplying basement highs that cover most of eastern NE China to track the intense denudation events and provenance changes through the *** found a great inconsistency between detrital age patterns of the modern river sands and the spatial proportions of the source *** detrital age distributions allow to re-evaluate the basement units that are mostly composed of the Triassic–Jurassic igneous suite and some metasedimentary units with Paleozoic ages,but the contribution from Proterozoic formations is *** the newly dated modern catchment detrital U-Pb ages,the region-wide compilation of the basement emplacement ages,and the U-Pb ages in the Cretaceous formations in NE China,we systematically refine the Cretaceous provenance *** the Early Cretaceous,the eastern satellite basins accumulated sediments from the Lesser Xing’an range(LXR)in the west,Zhangguangcai range(ZGCR)in the south,and the Nadanhada terrane(NT)in the *** sediment of the southern Songliao Basin derived from the North China Craton(NCC)and from ZGCR but barely from the Great Xing’an Range(GXR).The Jiamusi uplift(JU)did not provide sediments to the eastern satellite basins and the Songliao *** the Late Cretaceous,the eastern satellite basins received sediments from the exhumed JU but barely from ZGCR and *** Songliao Basin still accumula

关键词： Detrital zircon U-Pb Modern sediment Source to sink Provenance change NE China