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Chip morphology and cutting temperature of ADC12 aluminum alloy during high-speed milling

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Rare Metals 2021年第7期40卷 1915-1923页

作者： Xin-Xin Meng you-Xi Lin School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China

The ADC12 aluminum alloy is prone to severe tool wear and high cutting heat during high-speed milling because of its high *** study analyzes the highspeed milling process from the perspective of different chip *** influence of cutting temperature on chip morphology was expounded.A two-dimensional orthogonal cutting model was established for finite element analysis(FEA)of high-speed milling of ADC12 aluminum alloy.A theoretical analysis model of cutting force and cutting temperature was proposed based on metal cutting *** variations in chip shape,cutting force,and cutting temperature with cutting speed increasing were analyzed via *** results show that,with the increase in cutting speed,the chip morphology changes from continuous to serrated,and then back to *** serrated chip is weakened and the cutting temperature is lowered when the speed is lower than 600 m·min^(-1)or higher than 1800 m·min^(-1).This study provides a reference for reducing cutting temperature,controlling chip morphology and improving cutting tool life.

关键词： ADC12 aluminum alloy High-speed milling Chip morphology Cutting temperature Finite element analysis

Systematic error real-time registration based onmodified input estimation

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Journal of Systems Engineering and Electronics 2016年第5期27卷 986-992页

作者： jianjuan xiu kai dong you he Research Institute of Information Fusion Naval Aeronautical and Astronautical University Yantai 264001 China

In order to estimate the systematic error in the processof maneuvering target adaptive tracking, a new method is *** proposed method is a linear tracking scheme basedon a modified input estimation approach. A special augmentationin the state space model is considered, in which both the systematicerror and the unknown input vector are attached to thestate vector. Then, an augmented state model and a measurementmodel are established in the case of systematic error, andthe corresponding filter formulas are also given. In the proposedscheme, the original state, the acceleration and the systematicerror vector can be estimated simultaneously. This method can notonly solve the maneuvering target adaptive tracking problem in thecase of systematic error, but also give the system error value inreal time. Simulation results show that the proposed tracking algorithmoperates in both the non-maneuvering and the maneuveringmodes, and the original state, the acceleration and the systematicerror vector can be estimated simultaneously.

关键词： systematic error estimation maneuvering target,adaptive tracking augmented system model modified input estimationapproach.

Robust gain-scheduled missile autopilot design based on multifrequency extended state observers

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Chinese Journal of Aeronautics 2023年第12期36卷 390-407页

作者： Zonghua SUN Liaoni WU Yancheng you School of Aerospace Engineering Xiamen UniversityXiamen 361102China

This paper describes the design and implementation of a three-axis acceleration control autopilot for an asymmetric tail-controlled,skid-to-turn tactical *** an earlier flight test,degraded autopilot performance was attributed to multiple disturbances and uncertainties and the presence of hidden coupling terms,giving rise to a miss distance of greater than 20 *** address these issues,the missile dynamics are decomposed into the angular rate dynamics as fast and the acceleration dynamics as slow subsystem using the singular perturbation theory to analyze a multi-time-scale *** extended state observers are then incorporated into the gain scheduling technique to attenuate disturbances,thus enhancing the control performance *** the proposed engineering/practical design framework for missile autopilot,simple,conventional,and explicit tuning rules are *** the proposed control scheme can achieve input-to-state stability across the entire flight envelope under unknown but bounded *** advantages of the method over existing benchmark approaches are shown through nonlinear numerical *** is supported by evidence from a new flight test result with a miss distance of only 2 m.

关键词： Acceleration control Control engineering Disturbance rejection Multifrequency extended state observer Flight control systems Gain scheduling Singular perturbation

Lignin-based polymer with high phenolic hydroxyl group content prepared by the alkyl chain bridging method and applied as a dopant of PEDOT

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Frontiers of Chemical Science and Engineering 2023年第8期17卷 1075-1084页

作者： Nanlong Hong Jiahui Wang Jinhua you School of Chemical Engineering and Energy Technology Dongguan University of TechnologyDongguan 523808China

Inspired by the importance of the phenolic group to the electron transporting property of hole transport materials,phenolic hydroxyl groups were introduced in lignosulfonate(LS)via the alkyl chain bridging method to prepare phenolated-lignosulfonate(PLS).The results showed that the phenolic group was boosted from 0.81 mmol∙g^(–1) of LS to 1.19 mmol∙g^(–1) of *** electrochemical property results showed two oxidation peaks in the cyclic voltammogram(CV)curve of PLS,and the oxidation potential of the PLS-modified electrode decreased by 0.5 eV compared with that of *** result indicates that PLS is more easily oxidized than *** on the excellent electron transporting property of PLS,PLS was applied as a dopant in poly(3,4-ethylenedioxythiophene)(PEDOT,called PEDOT:PLSs).PLS showed excellent dispersion properties for ***,the transmittance measurement results showed that the transmittance of PEDOT:PLSs exceeded 85%in the range of 300–800 *** CV results showed that the energy levels of PEDOT:PLSs could be flexibly adjusted by PLS *** results indicate that the phenolic hydroxyl group of lignin can be easily boosted by the alkyl chain bridging method,and phenolated lignin-based polymers may have promising potential as dopants of PEDOT to produce hole transporting materials for different organic photovoltaic devices.

关键词： lignosulfonate phenolic group PEDOT:PLS hole extract layer energy level

Slowdown in China's methane emission growth

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National Science Review 2024年第8期11卷 114-124页

作者： Min Zhao Xiangjun Tian Yilong Wang Xuhui Wang Philippe Ciais Zhe Jin hongqin Zhang Tao Wang Jinzhi Ding Shilong Piao State Key Laboratory of Tibetan Plateau Earth System Resources and Environment(TPESRE) Institute of Tibetan Plateau Research Chinese Academy of Sciences University of Chinese Academy of Sciences Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University Laboratoire des Sciences du Climat et de l'Environnement LSCE/IPSLCEA-CNRS-UVSQUniversité Paris-Saclay Institute of Carbon Neutrality College of Urban and Environmental Sciences Peking University Institute of Atmospheric Physics Chinese Academy of Sciences

The unprecedented surge in global methane levels has raised global concerns in recent years,casting a spotlight on China as a pivotal *** has taken several actions to curb the methane emissions,but their effects remain ***,we developed the Global ObservatioN-based system for monitoring Greenhouse GAses for methane（GONGGA-CH4） and assimilate GO SAT XCH4observations to assess changes in China' s methane *** find the average rate of increase in China' s methane emissions(0.1±0.3 Tg CH4yr-2) during 2016-2021 slowed down compared to the preceding years（2011-2015）(0.9±0.5 Tg CH4yr-2),in contrast to the concurrent acceleration of global methane *** a result,the contribution of China to global methane emissions dropped ***,the slowdown of China' s methane emission is mainly attributable to a reduction in biogenic emissions from wetlands and agriculture,associated with the drying trend in South China and the transition from double-season to single-season rice cropping,while fossil fuel emissions are still *** results suggest that GONGGA-CH4provides the opportunity for independent assessment of China' s methane emissions from an atmospheric perspective,providing insights into the implementation of methane-related policies that align with its ambitious climate objectives.

关键词： methane emissions greenhouse gases data assimilation China Global ObservatioN-based system for monitoring Greenhouse GAses for methane

Size effect of deformation nanotwin bundles on their strengthening and toughening in heterogeneous nanostructured Cu

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Science China(Technological Sciences) 2021年第1期64卷 23-31页

作者： you ZeSheng LUO ShuSen LU Lei Herbert Gleiter Institute of Nanoscience Nanjing University of Science and TechnologyNanjing 210094China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Herein, we fabricated a heterogeneous nanostructured Cu with deformation nanotwin bundles(NTBs) embedded in a matrix of nanograins by means of dynamic plastic deformation at liquid nitrogen temperature. We conducted fracture mechanical measurements to investigate the effect of longitudinal length of the NTBs on their strengthening and toughening. Results suggest that an increase in the NTB length had a marginal influence on the tensile strength;however, it remarkably promoted both fracture initiation toughness and crack growth toughness. Longer NTBs are more effective not only in intrinsically enhancing crack tip plasticity by suppressing the strain localization and void nucleation but also in serving as crack bridges behind the crack front to extrinsically resist the fracture by shielding the crack tip.

关键词： fracture toughness nanotwins J-integral size effect toughening mechanism

Sequential Track Monitoring with Multiple 2-D Passive Sensors

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Journal of Systems Engineering and Electronics 1998年第2期9卷 31-39页

作者： Wang, Guohong He, you Naval Aeronautical Engineering Acad Yantai China

Track monitoring is a fast method of determining incorrect return-to-track and track-to-track assignments. An analytical method to evaluate the effectiveness of track monitoring was presented by reference [1]. In order to reduce the probability of initiating or accepting the ghost track, two sequential track monitoring algorithms, which use the inclination angles to form test statistics, are proposed in this paper. Two decision rules are given and the corresponding thresholds are derived. The paper also gives the estimation methods of the noncentral parameter of noncentral chi-square distribution when the true value of it is unknown, the algorithms can adaptively estimate the decision thresholds and can make sequential track monitoring decision on line. Simulation is also made and the results show that the proposed algorithms are effective and feasible.

关键词： Algorithms Computer simulation Decision theory Estimation Measurement errors Probability Tracking (position) Two dimensional

Maps Preserving Commutators on the Standard Borel Subgroup of the Unitary Group over a Field

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Algebra Colloquium 2016年第3期23卷 507-518页

作者： Hong you Xuemei Zhou Research Center of Natural Science Harbin Institute of Technology Harbin 150001 China Department of Mathematics Soochow University Suzhou Jiangsu 215006 China School of Mathematics Southwest Jiaotong University Leshan Sichuan 614202 China

Let F be a field with charF ≠ 2 and ｜F｜〉 9, and let B2n（F） be the standard Borel subgroup of the unitary group U2n（F） over F. For n ≥ 3, we obtain a complete description of all bijective maps preserving comm... 详细信息

关键词： maps preserving commutators standard Borel subgroup unitary group

Data-Driven Control of Linear Systems via Quantized Feedback

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Journal of Systems Science & Complexity 2024年第1期37卷 152-168页

作者： LI Xingchen ZHAO Feiran you Keyou Department of Automation and BNRist Tsinghua UniversityBeijing 100084China

Quantized feedback control is fundamental to system synthesis with limited communication *** sharp contrast to the existing literature on quantized control which requires an explicit dynamical model,the authors study the quadratic stabilization and performance control problems with logarithmically quantized feedback in a direct data-driven framework,where the system state matrix is not exactly known and instead,belongs to an ambiguity set that is directly constructed from a finite number of noisy system *** this end,the authors firstly establish sufficient and necessary conditions via linear matrix inequalities for the existence of a common quantized controller that achieves our control objectives over the ambiguity ***,the authors provide necessary conditions on the data for the solvability of the LMIs,and determine the coarsest quantization density via semi-definite *** theoretical results are validated through numerical examples.

关键词： Data-driven control linear matrix inequalities linear systems quantized control.