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Underwater acoustic signal denoising model based on secondary variational mode decomposition

Defence Technology（防务技术） 2023年第10期28卷 87-110页

作者： hong Yang Wen-shuai Shi guo-hui Li School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'anShaanxi710121China

Due to the complexity of marine environment,underwater acoustic signal will be affected by complex background noise during *** acoustic signal denoising is always a difficult problem in underwater acoustic signal *** obtain a better denoising effect,a new denoising method of underwater acoustic signal based on optimized variational mode decomposition by black widow optimization algorithm(BVMD),fluctuation-based dispersion entropy threshold improved by Otsu method(OFDE),cosine similarity stationary threshold(CSST),BVMD,fluctuation-based dispersion entropy(FDE),named BVMD-OFDE-CSST-BVMD-FDE,is *** the first place,decompose the original signal into a series of intrinsic mode functions(IMFs)by ***,distinguish pure IMFs,mixed IMFs and noise IMFs by OFDE and CSST,and reconstruct pure IMFs and mixed IMFs to obtain primary denoised *** the end,decompose primary denoising signal into IMFs by BVMD again,use the FDE value to distinguish noise IMFs and pure IMFs,and reconstruct pure IMFs to obtain the final denoised *** proposed mothod has three advantages:(i)BVMD can adaptively select the decomposition layer and penalty factor of VMD.(ii)FDE and CS are used as double criteria to distinguish noise IMFs from useful IMFs,and Otsu algorithm and CSST algorithm can effectively avoid the error caused by manually selecting thresholds.(iii)Secondary decomposition can make up for the deficiency of primary decomposition and further remove a small amount of *** chaotic signal and real ship signal are *** experiment result shows that the proposed method can effectively *** improves the denoising effect after primary decomposition,and has good practical value.

关键词： Underwater acoustic signal Denoising Variational mode decomposition Secondary decomposition Fluctuation-based dispersion entropy Cosine similarity

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Deposition of TiN/TiAlN multilayers by plasma-activated EB-PVD:tailored microstructure by jumping beam technology

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Rare Metals 2017年第8期36卷 651-658页

作者： guo-Yuan Yang Hui Peng hong-Bo guo Sheng-Kai Gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang UniversityBeijing 100191China Key Laboratory of Aerospace Materials and Performance(Ministry of Education) Beihang UniversityBeijing 100191China

Plasma-activated electron beam-physical vapor deposition（EB-PVD）was used for depositing nitride multilayer coatings in this *** from the conventional coating methods,the multilayers were obtained by manipulating electron beam（EB）to jump between two different evaporation sources alternately with variable frequencies（jumping beam technology）.The plasma activation was generated by a hollow cathode plasma *** deposition process was demonstrated by means of tailoring TiN/TiAlN multilayers with different modulation periods（M1：26.5 nm,M2：80.0 nm,M3：6.0 nm,M4：4.0 nm）.The microstructure and hardness of the multilayer coatings were comparatively studied with TiN and TiAlN singlelayer *** columnar structure of the coatings（TiN,TiAlN,M1,M2）is replaced by a glassy-like microstructure when the modulation period decreases to less than 10 nm（M3,M4）.Simultaneously,superlattice growth *** the decrease of modulation period,both the hardness and the plastic deformation resistance（H^3/E^2,H-hardness and E-elastic modulus）increase.M4coating exhibits the maximum hardness of（49.6±2.7）GPa and the maximum plastic deformation resistance of^0.74 GPa.

关键词： Nano-multilayer coatings Superlattice Plasmaactivation TiN/TiAlN EB-PVD Hardness

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Research status of inclusions in bearing steel and discussion on non-alloy deoxidation process

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Journal of Iron and Steel Research International 2023年第1期30卷 1-20页

作者： Lei Cao Li-guang Zhu Zhi-hong guo School of Metallurgy and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Materials Engineering Department Hebei Vocational University of Industry and TechnologyShijiazhuang 050091HebeiChina Department of Materials Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050090HebeiChina

Non-metallic inclusion in steel is a very key factor affecting the fatigue life and quality stability of high-quality bearing *** mainly affect the fatigue life and toughness of the material by affecting the continuity of the steel matrix,thereby endangering the safety and stability of the *** research progress of inclusion formation,removal and modification was *** on the current research status of Al deoxidation or Si deoxidation process,the feasibility of non-alloy deoxidation process for high-quality bearing steel was proposed and discussed.C or H_(2) is used as non-alloy deoxidizer,and the deoxidation products are CO and H_(2)O gases,which are easy to be removed from the molten *** are few studies on the non-alloy deoxidation process,especially the research and application of C or H_(2) deoxidation for high-quality bearing ***,the non-alloy deoxidation process is of great significance for reducing oxygen content and improving cleanliness of high-quality bearing ***,it is necessary to study the mechanism and kinetics of C and H_(2) deoxidation and analyze the factors affecting deoxidation effect systematically,so as to provide a solid theoretical basis for the practice of non-alloy deoxidation process for high-quality bearing steel.

关键词： High-quality bearing steel Non-metallic inclusion Non-alloy deoxidation C deoxidation H_(2)deoxidation

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Combined Molecular Dynamics Simulation and Rouse Model Analysis of Static and Dynamic Properties of Unentangled Polymer Melts with Different Chain Architectures

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Chinese Journal of Polymer Science 2021年第4期39卷 512-524,I0008页

作者： Pu Yao Lu-Kun Feng hong-Xia guo Beijing National Laboratory for Molecular Sciences Joint Laboratory of Polymer Sciences and MaterialsState Key Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Chain architecture effect on static and dynamic properties of unentangled polymers is explored by molecular dynamics simulation and Rouse mode analysis based on graph *** open chains,although they generally obey ideal scaling in chain dimensions,local structure exhibits nonideal behavior due to the incomplete excluded volume(EV)screening,the reduced mean square internal distance(MSID)can be well described by Wittmer'theory for linear chains and the resulting chain swelling is architecture dependent,i.e.,the more branches a bit stronger *** rings,unlike open chains they are compact in term of global *** to EV effect and nonconcatenated constraints their local structure exhibits a quite different non-Gaussian behavior from open chains,i.e.,reduced MSID curves do not collapse to a single master curve and fail to converge to a chain-length-independent constant,which makes the direct application of Wittmer's theory to rings quite *** from ideality is further evidenced by limited applicability of Rouse prediction to mode amplitude and relaxation time at high modes as well as the non-constant and mode-dependent scaled Rouse mode amplitudes,while the latter is architecture-dependent and even molecular weight dependent for *** chain relaxation time is architecture-dependent,but the same scaling dependence on chain dimensions does hold for all studied *** mode orthogonality at static state,the role of cross-correlation in orientation relaxation increases with time and the time-dependent coupling parameter rises faster for rings than open chains even at short time scales it is lower for rings.

关键词： Rouse model Unentangled chains Architecture Excluded volume effects

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Enhanced corrosion resistance of epoxy resin coating via addition of CeO_(2) and benzotriazole

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Chinese Journal of Chemical Engineering 2024年第3期67卷 89-96页

作者： Xu Han Ruijie guo Baolong Niu hong Yan College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

The use of fillers to enhance the corrosion protection of epoxy resins has been widely *** this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon *** electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive *** dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite *** the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of *** formation of corrosion products was analyzed using X-ray *** addition,the corrosion resistance mechanism of the coating was also discussed in detail.

关键词： Benzotriazole Cerium dioxide Corrosion resistance Carbon steel Epoxy resin coating Preparation

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Effect of Mn Content on Microstructure and Cryogenic Mechanical Properties of a 7%Ni Steel

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Acta Metallurgica Sinica(English Letters) 2018年第7期31卷 699-705页

作者： hong-Wei Cao Xing-hong Luo guo-Feng Zhan Shi Liu School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China CAS Key Laboratory of Nuclear Materials and SafetyAssessment Institute of Metal ResearchChinese Academyof SciencesShenyang 110016China Research and Development Center of Wuhan Iron and Steel(Group)Corp Wuhan 430080China

The effect of Mn content on the microstructure and cryogenic mechanical properties of a 7% Ni steel was investigated within the Mn content range from 0.13% to 0.36%. The microstructure of the steel as determined by optical microscopy, scanning electron microscopy, transmission electron microscopy, electron backscattering diffraction and X-ray diffraction was presented, and the low-temperature mechanical properties were given. The size of prior austenite grain did not change a lot as Mn content increased. Film-like reversed austenite, having high stability, was found mainly in the specimens with lower Mn content; however, in the specimen with the highest Mn content, the role of Mn was not obvious in stabilizing reversed austenite. Besides, with increasing Mn content, the amount of reversed austenite at grain boundaries gradually decreased. The variable Mn content had a significant effect on cryogenic toughness~ but not apparent on cryogenic tensile strength or yield strength. An excellent combination of cryogenic tensile and impact properties was obtained when Mn content of steel was 0.13%.

关键词： 7% Ni steel Mn content Microstructure Reversed austenite Cryogenic mechanical properties

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Optimal car-following control for intelligent vehicles using online road-slope approximation method

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Science China(Information Sciences) 2021年第1期64卷 94-109页

作者： hongqing CHU Lulu guo hong CHEN Bingzhao GAO State Key Laboratory of Automotive Simulation and Control Jilin University Center for Cyber-Physical systems University of Georgia Clean Energy Automotive Engineering Center Tongji University

The design of a car-following control system is a multiobjective optimization problem that involves issues in rider safety, ride comfort, and fuel economy. This study proposes a hierarchical design of optimal car-following control where the system is intuitively split into two subsystems with different dynamic properties. Specifically, the high-level subsystem is a linear car-following system with a measurable disturbance of the preceding vehicle’s acceleration, while the low-level subsystem is a nonlinear accelerationtracking system with an unmeasurable road slope. In the design of optimal car-following control, the measurable disturbance of the preceding vehicle’s acceleration is considered from a theoretical perspective, and the unmeasurable road slope is estimated by a novel engineering-oriented approximation method to reduce the influence of driveline oscillation. The performance of the proposed optimal control scheme is evaluated through simulation and real-vehicle experiments, which show that the proposed control algorithm provides a satisfactory road-slope approximation accuracy and that the car-following performance of the proposed optimal control system is better than that of a factory-installed adaptive cruise controller.

关键词： car-following control road-slope approximation hierarchical design linear quadratic regulator intelligent vehicle

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Application of complex nonlinear modes to determine dry whip motion in a rubbing rotor system

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Chinese Journal of Aeronautics 2021年第1期34卷 209-225页

作者： Pingchao YU Yanhong MA Jie hong guo CHEN College of Civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 211106China School of Energy and Power Engineering Beihang UniversityBeijing 100083China Collaborative Innovation Center of Achanceci Aero-Engine Beihang UniversityBeijing 100083China

Dry whip motion is an instability of rubbing rotor system and may cause catastrophic failures of rotating *** to now,the related mechanisms of the dry whip is still not well *** paper aims to build the relationship between the complex nonlinear modes and the dry whip motion,and propose an effective method to predict the response characteristics and existence boundary of the dry whip through complex nonlinear *** the first time,the paper discusses how to use the complex nonlinear modes to predict the dry whip systematically,and as a consequence,the mechanism of the relationship between the complex nonlinear mode and the dry whip is *** results show that the Backward Whirl(BW)mode motion of the rubbing rotor system dominates the response characteristics and the existence boundary of dry *** whirl amplitude and whirl frequency of dry whip are equal to the modal amplitude and modal frequency of the BW mode at the jump up point where the modal damping is equal to *** existence boundary corresponds to the critical rotation speed where the minimum of the modal damping of the BW mode motion is exactly equal to ***,the proposed nonlinear modal method in this article is very effective for the prediction of dry whip of the more complicated practical rotor system,which has been verified by applying the predicted method into a rubbing rotor test rig.

关键词： Complex nonlinear mode Dry whip Existence boundary Response characteristics

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Influence of Nb Content on Microstructure and Mechanical Properties of a 7%Ni Steel

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Acta Metallurgica Sinica(English Letters) 2018年第9期31卷 975-982页

作者： hong-Wei Cao Xing-hong Luo guo-Feng Zhan Shi Liu School of Materials Science and Engineering University ofScience and Technology of ChinaShenyang 110016China CAS Key Laboratory of Nuclear Materials and SafetyAssessment Institute of Metal ResearchChinese Academyof SciencesShenyang 110016China Research and Development Center of Wuhan Iron and Steel(Group)Corp Wuhan 430080China

The influence of Nb content on the microstructure and cryogenic mechanical properties of a 7%Ni steel was investigated within the Nb content range from 0 to 0.05%. The microstructure was characterized by optical microscope, scanning electron microscope, transmission electron microscopy and X-ray diffraction, and the low-temperature mechanical property tests were conducted. The Nb addition can effectively refine the prior austenite grains and microstructure of the steel. Fine niobium precipitates with a diameter of about 10-50 nm were observed. They tend to be spherical and locate mainly in the vicinity of grain boundaries. Although there are considerable amounts of reversed austenite forming at grain boundaries in the specimen containing the highest Nb content, no Nb element was detected in such reversed austenite, which implies that Nb element did not affect the formation of the reversed austenite directly. Mechanical test results suggest that the strength of the 7%Ni steel is not simply in relation to the prior austenite grain size, but also depends on the amount of reversed austenite. On the other hand, the grain refinement, enhanced with increasing Nb content, has a good effect on cryogenic toughness.

关键词： 7%Ni steel Nb content Niobium precipitate Reversed austenite Cryogenic mechanical properties

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One-pot synthesis of 7-aryl-11,12-dihydrobenzo[h]pyrimido-[4,5-b]quinoline-8,10(7H,9H)-diones via three-component reaction in ionic liquid

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Chinese Chemical Letters 2010年第12期21卷 1435-1438页

作者： hong Yun guo Yi Yu College of Chemical Engineering and Materials Zhejiang University of Technology Hangzhou 310014 China

A series of new 7-aryl-11,12-dihydrobenzo[h]pyrimido-[4,5-b]quinoline-8,10（7H,9H）-diones were synthesized via three-component reaction of aldehydes,l-naphthylamine and barbituric acid in ionic *** method provided se... 详细信息

关键词： Aldehyde 1-Naphthylamine Barbituric acid Ionic liquid

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