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High AOA decoupling control for aircraft based on ADRC

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Journal of Systems Engineering and Electronics 2020年第2期31卷 393-402页

作者： liu junjie SUN Mingwei CHEN Zengqiang SUN Qinglin College of Artificial Intelligence Nankai UniversityTianjin 300350China

In this paper, a practical decoupling control scheme for fighter aircraft is proposed to achieve high angle of attack(AOA)tracking and super maneuver action by utilizing the thrust vector technology. Firstly, a six degree-of-freedom(DOF) nonlinear model with 12 variables is given. Due to low sufficiency of the aerodynamic actuators at high AOA, a thrust vector model with rotatable engine nozzles is derived. Secondly, the active disturbance rejection control(ADRC) is used to realize a three-channel decoupling control such that a strong coupling between different channels can be treated as total disturbance, which is estimated by the designed extended state observer. The control surface allocation is implemented by the traditional daisy chain method. Finally,the effectiveness of the presented control strategy is demonstrated by some numerical simulation results.

关键词： high angle of attack(AOA) decoupling control linear extended state observer(LESO) active disturbance rejection control(ADRC) thrust vector technology control allocation

City-wide vehicle dispatching for multi-hop ridesharing package delivery

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The Journal of China Universities of Posts and Telecommunications 2020年第5期27卷 82-90页

作者： Zhao Xiyu Zhang Xuefei liu junjie Wang Yining School of Telecommunication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

The city-wide ridesharing package delivery is becoming popular as it provides a convenience such as extra profits to the vehicle’s driver and high traffic efficiency to the *** vehicle dispatching is a significant issue to improve the ridesharing efficiency in package *** classic one-hop ridesharing package delivery requires the highly similar paths between the package and the vehicle given by the limited detour time,which depresses the ridesharing *** tackle this problem,a city-wide vehicle dispatching strategy for the multi-hop ridesharing package delivery was proposed,where a package is permitted to be delivered sequentially by different vehicles,until arriving the *** study formulates the vehicle dispatching as a maximum multi-dimensional bipartite matching problem with the goal of maximizing the total saving distance given by the limited detour time and ridesharing capacity.A multi-hop ridesharing vehicle dispatching algorithm was proposed to solve this problem by selecting the farthest reachable locker and multi-dimensional *** results based on real vehicle dataset of Beijing demonstrate the effectiveness and efficiency of the proposed vehicle dispatching strategy.

关键词： multi-hop ridesharing package delivery vehicle dispatching

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Topological prime

Science China(Technological Sciences) 2020年第7期63卷 1314-1322页

作者： YANG XuXu YANG CanHui liu junjie YAO Xi SUO ZhiGang John A.Paulson School of Engineering and Applied Sciences Kavli Institute for Bionano Science and TechnologyHarvard UniversityCambridge MA 02138USA State Key Laboratory of Fluid Power&Mechatronic System Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering Mechanics and Center for X-MechanicsZhejiang UniversityHangzhou 310027China Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055China Key Lab for Special Functional Materials of Ministry of Education Henan UniversityKaifeng 475004China

This paper describes a general method, called topological prime, to stitch functional groups to a substrate of entropic polymer network. The precursor of a topological primer contains polymers, crosslinkers, and coupling agents. When the precursor is applied on the surface of the substrate, the crosslinkers link the primer polymers into a primer network, in topological entanglement with the substrate network, while the coupling agents link the primer network to the functional groups. The use of topological prime is demonstrated by priming a hydrophobic elastomer of an arbitrary shape for hydrophilic coating. We describe an approach that fulfills two fundamental requirements: wetting and adhesion. The coated elastomer maintains hydrophilicity and lubricity after stretch, scratch, swell, and slide. As a further demonstration, a hydrogel substrate is primed for hydrophobic coating. Topological prime opens an enormous space for applications in engineering and biomedicine.

关键词： elastomer hydrogel hydrophilic coating topological prime functional groups

IDRMS: an improved dynamic replication management scheme for cloud storage

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The Journal of China Universities of Posts and Telecommunications 2018年第4期25卷 66-74页

作者： Wang Jun Wang Yue Wang Menglin liu junjie Department of Communication and Information Engineering Nanjing University of Posts and Telecommunications

Cloud storage is getting more and more popular as a new trend of data management. Data replication has been widely used to increase the data availability in cloud storage systems. However,most data replication schemes do not fully consider cost and latency issues when users need large amounts of remote replicas. We present an improved dynamic replication management scheme( IDRMS). By adding a prediction model,the optimal allocation of replicas among the cloud storage nodes is determined that the total communication cost and network delay are minimal. When the local data block is frequently requested,the data replicas can be moved to a closer or cheaper node for cost reduction and increased efficiency. Moreover,we replace the B+tree with the B*tree to speed up the search and reduce workload with the lowest blocking probability. We define the value of popularity to adjust the placement of replicas dynamically. We divide the data nodes in the network into hot nodes and cool nodes. By changing to visit cool nodes instead of hot nodes,we can balance the workload in the network. Finally,we implement IDRMS in Matlab simulation platform and simulation results demonstrate that IDRMS outperforms other replication management schemes in terms of communication cost and load balancing for large-scale cloud storage.

关键词： cloud storage dynamic replication management blocking probability prediction load balancing

Vehicle-oriented ridesharing package delivery in blockchain system

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Digital Communications and Networks 2024年第4期10卷 1014-1023页

作者： Xuefei Zhang junjie liu Yijing Li Qimei Cui Xiaofeng Tao Ren Ping liu Wenzheng Li Department of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing100876China Department of Electrical and Data Engineering University of Technology SydneySydneyAustralia Department of Information Technology Beijing University of TechnologyBeijing100876China

Package delivery via ridesharing provides appealing benefits of lower delivery cost and efficient vehicle *** existing ridesharing systems operate the matching of ridesharing in a centralized manner,which may result in the single point of failure once the controller breaks down or is under *** tackle such problems,our goal in this paper is to develop a blockchain-based package delivery ridesharing system,where decentralization is adopted to remove intermediaries and direct transactions between the providers and the requestors are *** complete the matching process under decentralized structure,an Event-Triggered Distributed Deep Reinforcement Learning(ETDDRL)algorithm is proposed to generate/update the real-time ridesharing orders for the new coming ridesharing requests from a local *** results reveal the vast potential of the ETDDRL matching algorithm under the blockchain framework for the promotion of the ridesharing ***,we develop an application for Android-based terminals to verify the ETDDRL matching algorithm.

关键词： Blockchain Dynamic matching Ridesharing package delivery

Frequency Synchronization Based on a Cascading Cross-Correlation Function for CO-FBMC-OQAM

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Chinese Journal of Electronics 2020年第4期29卷 724-730页

作者： WANG Daobin CHEN Bo LYU Ningning WANG Wei liu junjie YUAN Lihua School of Science Lanzhou University of Technology School of Electrical and Information Engineering Lanzhou University of Technology

We present a robust frequency synchronization algorithm for the Coherent optical Offset quadrature-amplitude modulation based Filter-bank multicarrier(CO-FBMC-OQAM) *** is a two-stage method operating in the frequency domain, which expands the estimated range of the normalized fractional frequency offset to(-1, +1).We designed and introduced a cascading cross-correlation function of real-valued pilots to roughly estimate the frequency offset in the first *** residual frequency offset was accurately tracked by a non-cascading cross-correlation function *** approach enlarges the maximum estimated range, and also resists interference and noise.A CO-FBMC-OQAM system with the sampling rate of 50 Gsample/s was numerically investigated to evaluate the frequency-offset estimation and compensation *** obtained results prove that the proposed frequency synchronization method can correct the laser-frequency offset and improve the transmission performance significantly.

关键词： CO-FBMC-OQAM Carrier frequency offset Frequency synchronization Cascading cross-correlation function

Experimental Investigation on Pouch Lithium-ion Battery Thermal Management with Mini-Channels Cooling Plate Based on Heat Generation Characteristic

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Journal of Thermal Science 2022年第3期31卷 816-829页

作者： REN Honglei JIA Li DANG Chao YANG Chengliang JIA Hongyang liu junjie Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China CRRC Dalian Institute Co. LTD.Dalian116021China

An electrochemical thermal coupling model of lithium battery was established to study the heat generation characteristic in this *** simulation results showed that the heat generation density of the battery increased with the discharge *** the discharge process,the heat generation density of the battery increased *** 2.5C discharge rate,the heat generation density at the end of discharge was 1.82 times of that at the beginning of *** heat generation density at different areas of the battery was not uniform and 46%of the total ohmic heat was generated near the electrode tabs.A cooling plate with variable mini-channels was designed to improve the temperature non-uniformity caused by the heat generation characteristic.A cooling plate with uniform mini-channels was designed for compared *** experiments were conducted with deionized water and refrigerant R141b and carried out with 1.5C,2C and 2.5C discharge *** results showed that the cooling plate with variable mini-channels had a better cooling performance in both single-phase and two-phase cooling conditions.

关键词： lithium-ion battery mini-channels cooling plate heat generation characteristic thermal management

Crafting host materials for narrowband blue OLEDs with low efficiency roll-off by the medium-ring strategy

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Science China Chemistry 2024年第10期67卷 3265-3270页

作者： Yuanyuan Bao Anping Luo Jingbo Lan junjie liu Zhengyang Bin Jingsong You Key Laboratory of Green Chemistry and Technology of Ministry of Education College of ChemistrySichuan UniversityChengdu 610064China

The pursuit of high-performance narrowband blue organic light-emitting diodes(OLEDs)is of paramount importance in both academic research and industrial *** obvious strides have been made in the design of narrowband blue emitters,the development of appropriate host materials has evidently trailed ***,we introduce a medium-ring strategy for crafting host molecules based on the heptagonal tribenzo[b,d,f]azepine(TBA)*** twisted three-dimensional(3D)architecture of the TBA framework not only endows the host molecules with fast hole-transporting pathways but also effectively reduces exciton *** with two TBA units,DTBA,synthesized with ease,demonstrates a huge horizontal orientation factor(Θ//)of 93.5%and a broad emission spectrum for accelerating the energy transfer process in the emitting layer,which contributes to enhancing device *** have fabricated high-performance narrowband blue OLEDs using DTBA as the host,FIrpic as the phosphor sensitizer,and the widely used boron-nitrogen-containing multiple resonance emitter *** devices exhibit a maximum external quantum efficiency(EQEmax)as high as 31.0%with an impressively lowefficiency *** at a high luminance level of 10,000 cd m^(-2),the EQE value remains noteworthy at 20.3%,marking a significant advancement in BCz-BN-based devices.

关键词： host molecule blue organic light-emitting diode low-efficiency roll-off multiple resonance C–H activation

Probing non-polarizable liquid/liquid interfaces using scanning ion conductance microscopy

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Science China Chemistry 2020年第3期63卷 411-418页

作者： Yaxiong Gu Ye Chen Yifan Dong junjie liu Xianhao Zhang Mingzhi Li Yuanhua Shao Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The study of microscopic structure of a liquid/liquid interface is of fundamental importance due to its close relation to the thermodynamics and kinetics of interfacial charge transfer *** this article,the microscopic structure of a non-polarizable water/nitrobenzene(W/NB)interface was evaluated by scanning ion conductance microscope(SICM).Using SICM with a nanometer-sized quartz pipette filled with an electrolyte solution as the probe,the thickness of this type of W/NB interface could be measured at sub-nanometer scale,based on the continuous change of ionic current from one phase to another *** effects for thicknesses of the non-polarizable W/NB interfaces with different electrolyte concentrations,the Galvani potentials at the interface and the applied potentials on the probe were measured and systematically *** experimental setups,that is an organic phase up and an aqueous down,and a reverse version,were employed to acquire the approach *** data were compared with those of an ideal polarizable interface under the similar experimental conditions,and several characteristics of non-polarizable interfaces were *** thickness of a non-polarizable interface increases with the decrease of electrolyte concentration and the increase of applied potential,which is similar to the situation of a polarizable liquid/liquid *** also find that the Galvani potential across a non-polarizable interface can also influence the interfacial thickness,this phenomenon is difficult to observe when using polarizable *** importantly,by the comparison of two kinds of liquid/liquid interfaces,we experimentally proved that much more excess ions are gathered in the space charge layer of non-polarizable interfaces than in that of polarizable *** results are consistent with the predictions of molecular dynamic simulations and X-ray reflectivity measurements.

关键词： micro/nano pipettes scanning ion conductance microscopy microstructure of a non-polarizable liquid/liquid interface