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An experimental study of noise generated by tandem blades

Chinese Journal of Aeronautics 2025年第2期38卷 143-160页

作者： Xiaolong TANG Fan TONG Chao WANG Jue DING Guangming LI Xiaoquan YANG Shanghai Institute of Applied Mathematics and Mechanics Shanghai Frontier Science Center of MechanoinformaticsShanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Key Laboratory of Aerodynamic Noise Control China Aerodynamics Research and Development CenterMianyang 621000China Equipment Design and Testing Technology Research Institute China Aerodynamics Research and Development CenterMianyang 621000China

To facilitate the low-noise design of tandem lift bodies as applied in aeroengines and aircraft,the acoustic features of tandem blades are investigated by wind-tunnel *** is further specialized for the rotating blades applied in contra-rotating open rotors under the concept of frozen-rotor.A 70-channel phased microphone array and nine high-precision free-field microphones are *** beamforming method,enhanced by a source filtering technique,is employed to locate noise sources,providing insights into the source patterns of blade-blade interaction noise concerning flow speed,blade spacing,and aft blade *** results show the following:(A)Sources of tandem-blade noise exist in the form of concentrated source clusters,resulting in two major clusters:the mid-span interaction noise and the tip-induced noise.(B)These source clusters tend to separate as flow speed or blade spacing increases.(C)By increasing blade spacing,the band-pass filtered overall sound pressure level is reduced by 2.9 dB.(D)A two-phase noise suppression pattern is observed with blade clipping,resulting in a total reduction of 3.0 dB for the interaction noise through the removal of tip-induced noise sources and the replacement of mid-span noise *** on these findings,suggestions concerning blade spacing and clipping are discussed.

关键词： Tandem blades Contra-rotating open rotor Noise Beamforming Blade spacing and clipping Wind tunnel test

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High concentration of Ti^(3+)in C-TiO_(x)nanosheets boosting efficient photodegradation

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Science China(Technological Sciences) 2025年第3期68卷 156-166页

作者： Chongbei WU Xuan LI Haibin WANG Jiaxin TANG Shuai WEI Yuanyuan WU Aobing WANG Jizhou JIANG Hebei Key Laboratory of Man-machine Environmental Thermal Control Technology and Equipment Hebei Vocational University of Technology and EngineeringXingtai054000China School of Materials Science and Engineering Key Laboratory of Green Chemical Engineering Process of Ministry of EducationEngineering Research Center of Phosphorus Resources Development and Utilization of Ministry of EducationWuhan Institute of TechnologyWuhan430205China

Semiconductor photocatalysis holds significant promise for addressing dye-pollution in ***,the efficiency of photocatalytic water purification is constrained by the weak light absorption capacity and low active site distribution of *** a bottom-up approach,carbon-doped TiO_(x)(C-TiO_(x))nanosheets with high concentrations of Ti^(3+)active sites were fabricated by etching the Al element in Ti_(3)Ai C_(2)with H_(2)O_(2).Experimental evidence demonstrates that the optimal C-TiO_(x)nanosheets exhibit high activity for the photocatalytic degradation of methylene blue,achieving a degradation rate of 100%within 50 *** introduction of carbon into the C-TiO_(x)nanosheets induces a red shift in the absorption edge,boosting the migration of photo-generated charge ***,there is a significant correlation between the concentration of Ti^(3+)active sites and the density of oxygen vacancies in the C-TiO_(x)nanosheets,which synergistically influence the photocatalytic degradation performance of MB dye wastewater.

关键词： bottom-up strategies C-TiO_(x)nanosheets high-concentrations Ti^(3+) photocatalytic degradation

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Modulating Electromagnetic Genes Through Bi-Phase High-Entropy Engineering Toward Temperature-Stable Ultra-Broadband Megahertz Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第7期 262-277页

作者： Xiaoji Liu Yuping Duan Nan Wu Guangming Li Yuan Guo Jiangyong Liu Ning Zhu Qiang Wang Lin Wang Zichen Xu Hao Wei Guojun Wang Zhijia Zhang Songsong Zhang Wenjun Zhou Teng Ma Tongmin Wang Qingdao Innovation and Development Base of Harbin Engineering University Harbin Engineering University Key Laboratory of Solidification Control and Digital Preparation Technology School of Materials Science and EngineeringDalian University of Technology National Key Laboratory of Electromagnetic Effect and Security On Marine Equipment China Ship Development and Design Center Wuhan Second Ship Design and Research Institute

Magnetic absorbers with high permeability have significant advantages in lowfrequency and broadband electromagnetic wave （EMW） ***,the insufficient magnetic loss and inherent high conductivity of existing magnetic absorbers limit the further expansion of EMW absorption ***,the spinel （FeCoNiCrCu）3O4high-entropy oxides （HEO） are successfully constructed on the surface of FeCoNiCr0.4Cu0.2high-entropy alloys （HEA） through low-temperature oxygen bath *** the one hand,HEO and HEA have different magnetocrystalline anisotropies,which is conducive to achieving continuous natural resonance to improve magnetic *** the other hand,HEO with low conductivity can serve as an impedance matching layer,achieving magneto-electric *** the thickness is 5 mm,the minimum reflection loss （RL） value and absorption bandwidth （RL<-5 d B） of bi-phase high-entropy composites （BPHEC） can reach-12.8 d B and 633 MHz,*** RCS reduction value of multilayer sample with impedance gradient characteristic can reach 18.34 d B *** addition,the BPHEC also exhibits temperaturestable EMW absorption performance,high Curie temperature,and oxidation *** absorption bandwidth maintains between 593 and 691 MHz from-50 to 150℃.This work offers a new and tunable strategy toward modulating the electromagnetic genes for temperature-stable ultra-broadband megahertz EMW absorption.

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research on Navigation and Positioning technology for Autonomous Recovery of Unmanned Surface Vehicles 30

Research on Navigation and Positioning Technology for Autono...

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30th Saint Petersburg International Conference on Integrated Navigation Systems, ICINS 2023

作者： Xu, Chen Cai, Li-Ming Sun, Xue-Jiao Hu, Chang-Qing Li, Qing-Zhou Beijing Institute of Aerospace Control Devices Beijing China Aero-Times Marine Equipment Technology Development Co. Qingdao China Intelligent Unmanned System Overall Technology Research and Development Center China Aerospace Science and Technology Corporation Beijing China Laoshan Laboratory Qingdao China

ISBN: (纸本)9785919950950

The launch and recovery of Unmanned Surface Vehicles (USV) have long relied on manual assistance, which is one of the important factors limiting the wide application of USV in practical engineering. Navigation and positioning technology is the key to achieve autonomous recovery of USV. However, at present, the recovery process of USV basically still adopts manual remote control means, with high security requirements and low level of intelligence. This paper firstly describes the current situation of the application of navigation and positioning technology in the process of autonomous recovery of USV from two aspects: long-range USV navigation and positioning technology and close-range target relative positioning technology. By combining the characteristics of INS, GNSS, DVL and vision sensors, the framework of robust navigation system for the autonomous recovery of USV is designed for each stage of the recovery process. Then the key technologies involved are analyzed, including USV multi-source navigation information fusion technology and close-range visual relative positioning technology, and the corresponding adaptive federal Kalman filter algorithm and monocular visual positioning system algorithm are designed to realize accurate navigation and positioning in the autonomous recovery of USV. Finally, the navigation and positioning techniques in the autonomous recovery of USV are summarized and prospected. © 2023 Concern CSRI Elektropribor, JSC.

关键词： Adaptive filtering

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Simultaneous adsorption of As(Ⅲ) and Pb(Ⅱ) by the iron-sulfur codoped biochar composite:Competitive and synergistic effects

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Journal of Environmental Sciences 2023年第3期125卷 14-25页

作者： Yijun Chen Qintie Lin Xiaoqing Wen Jin He Haoyu Luo Quanfa Zhong Libin Wu Jiaqi Li Guangdong Industrial Contaminated Site Remediation Technology and Equipment Engineering Research CenterSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of EducationSchool of Environment and EnergySouth China University of TechnologyGuangzhou 510006China Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education Institute of Environmental and Ecological EngineeringGuangdong University of TechnologyGuangzhou 510006China

Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great *** this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(Ⅲ) and Pb(Ⅱ).The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic *** mechanism of As(Ⅲ) removal could be illustrated by surface complexation,oxidation and *** addition to precipitation and complexation,the elimination mechanism of Pb(Ⅱ) also contained ion exchange and electrostatic *** and synergistic effects existed simultaneously in the co-contamination *** suppression of As(Ⅲ) was ascribed to competitive complexation of the two metals on Fe/S-BC,while the synergy of Pb(Ⅱ) was attributed to the formation of the PbFe2(AsO_(4))2(OH)*** experiments revealed that Fe/S-BC had outstanding ability to remove As(Ⅲ) and Pb(Ⅱ),regardless of pH dependency and interference by various coexisting *** maximum adsorption capacities of the Fe/S-BC for As(Ⅲ) and Pb(Ⅱ) were 91.2 mg/g and 631.7 mg/g,***/S-BC could be treated as a novel candidate for the elimination of As(Ⅲ)-Pb(Ⅱ) combined pollution.

关键词： Iron-sulfur codoped Biochar Arsenic and lead Co-contamination remediation

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Numerical study of short-circuiting flow and particles in a gas cyclone

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Particuology 2023年第1期72卷 81-93页

作者： Sijie Dong Chenwen Wang Zihui Zhang Qinyu Cai Kejun Dong Teng Cheng Bo Wang Key Laboratory of Western China’s Environmental Systems of Ministry of Education Engineering Research Center of Fine Particle Pollution Control Technology and Equipment of Gansu ProvinceCollege of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Key Laboratory of Resource Environment and Sustainable Development of Oasis of Gansu Province College of Geography and Environmental ScienceNorthwest Normal UniversityLanzhou 730000China Center for Infrastructure Engineering Western Sydney UniversityPenrithNSW 2751Australia

Short-circuiting flow is an important secondary flow in gas cyclones, which has a negative impact on the separation performance. To improve the understanding of the short-circuiting flow and guide the optimization of gas cyclones, this paper presents a numerical study of a cyclone using computational fluid dynamics. Based on the steady flow field, three methods were adopted to investigate the formation mechanism and characteristics of the short-circuiting flow and particles. The temporal variation of the tracer species concentration distribution reveals that the formation mechanism of the short-circuiting flow is the squeeze between the airflows entering the annular space of the gas cyclone at different times. The short-circuiting flow region, distinguished through the spatial distribution of the moments of age, is characterized by a small mean age and a large coefficient of variation. The proportion of the short-circuiting particles increases with the increase of the inlet velocity only for small particles. But with the increase of particle size, the proportion of the short-circuiting particles decreases faster at higher inlet velocities, resulting in significant differences in collection efficiency curves.

关键词： Gas cyclone Short-circuiting flow Computational fluid dynamics Species transport Moment of age Particle tracking

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research on the impact of porous media on the flow and acoustic field characteristics for high-speed jet impinging on inclined plate

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Zhendong yu Chongji/Journal of Vibration and Shock 2025年第12期44卷 259-268and307页

作者： Feng, Keying Xia, Jing Peng, Yehui Zhao, Kun Shi, Jingyu Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and Technology Xiangtan411201 China Key Laboratory of Aerodynamics Noise Control China Aerodynamics Research and Development Center Mianyang621000 China

The noise from the impact of carrier-based aircraft wake on the deflector plate seriously threatens the health and safety of ground crew, as well asthe equipment on the aircraft carrier. This problem can be simplified to the noise of high-speed jets impacting the deflector plate. A numerical method combining three-dimensional large eddy simulation and FW-H acoustic analogy was employed to investigate the impact of incorporating porous media onto the swash plate' s surface on both the high-speed jet impingement on flow field and the acoustic field . The noise reduction trends was revealed associated with variations in the physical properties of the porous media. Additionally, the mechanisms was analyzed in detail by which porous media influence several types of typical noise, starting from the root cause of flow changes. It is shown that porous media can effectively reduce the discrete monotone and turbulent mixing noise in the jet impingement on flow field. An optimal combination of physical parameters exists, offering the best noise reduction effect. For instance, the porous model with a thickness of 20 mm and PPI of 30 can reduce the discrete monotone near 2 312 Hz up to 19. 79 dB, which results in the total upstream SPL reduction of 6. 92 dB;the suppression of discrete noise by porous media is based on the following principles: porous media affects the stability between the third and forth shock grille, thereby destroying the self-excitation conditions that are closely related to the formation of the feedback loop. The effect of the porous medium on the turbulent mixing noise originates from its destructive impact on the large-scale vortices and its adsorptive effect on the small-scale vortices. This suppresses or transfers the low and medium-frequency broadband noise and effectively reduces the turbulence kinetic energy intensity and pressure fluctuations near the wall surface. © 2025 Chinese Vibration Engineering Society. All rights reserved.

关键词： Large eddy simulation

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Dual-Branch Transfer Learning in Raman Spectroscopy for Bacterial Quantitative Analysis

SSRN

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SSRN 2023年

作者： Li, Qifeng Yang, Yunpeng Wu, Jianing Wei, Chunsheng Xia, Hua Han, Yangguang Ma, Xiangyun School of Precision Instrument and Opto-electronics Engineering Tianjin University Tianjin300072 China State Key Laboratory of Precision Measurement Technology and Instruments Tianjin University Tianjin300072 China School of Narcotics Control and Public Order Studies Criminal Investigation Police University of China Shenyang110854 China Research and Development Center of Narcotics Control Technology and Equipment Shenyang110854 China

Accurate quantification of bacteria is critical for ensuring food safety, advancing biomedical research, and a range of other pressing concerns. Raman spectroscopy is a popular technique for quantitative analysis due to its benefits of being fast, non-destructive, and highly sensitive. However, the accuracy of the transfer model is often limited by factors such as differences in equipment and environmental noise, which limits the popularization of Raman spectroscopy. In this paper, we propose a approach that overcomes this challenge by introducing a dual branch network based on Continuous Wavelet Transform (CWT) for model transfer. Our model comprises dual branches that perform distinct tasks. The spectral learning branch is responsible for extracting features from the spectral domain. The time-frequency map learning branch employs CNNs for extracting the multi-scale information-rich features. The proposed method is used for the quantitative analysis of Escherichia coli. The proposed approach significantly outperforms traditional methods in improving prediction accuracy. It offers a much-needed solution to the long-standing challenge of Raman spectroscopy in the field of bacterial quantitative analysis. With our approach, we can expect to see Raman spectroscopy more widely adopted in the future. © 2023, The Authors. All rights reserved.

关键词： Raman spectroscopy

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A DCA Attack Scheme and a Genetic Algorithm-based Intelligent Fault Injection Algorithm For White-Box AES Implementation 17

A DCA Attack Scheme and a Genetic Algorithm-based Intelligen...

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17th IEEE International Conference on Anti-Counterfeiting, Security, and Identification, ASID 2023

作者： Pan, Yuyang Wu, Yi Shang, Yulong Gao, Bo Zhao, Yulin Ma, Zhe Li, Yanzhao Wang, Xin Zhang, Zusong Wang, Chi Li, Mi Zhou, Ding Bank Card Test Center Product Testing Department Beijing China Beijing SanTel Technology and Trading Co. Ltd. Industrial Development Center Beijing China Technology Co. Ltd. Project Development Department Beijing China Shenzhen State Microelectronics Co. Ltd. Research Institute Shenzhen China Huawei Technologies Co. Ltd. Shenzhen China Beijing Institute of Automatic Control Equipment Beijing China

ISBN: (纸本)9798350319613

In this paper we attack the white-box AES implementation with Differential Correlation Analysis (DCA) and fault injection, which are major risks the white-box AES implementation is facing now. A differential computation analysis (DCA) attack strategy is presented targeted at the implementation of the white-box AES algorithm based on a combination T-box. Using the DCA attack method, 16 subkeys are extracted successfully, which underscores the presence of a notable side-channel security vulnerability within the white-box AES encryption scheme. In order to improve the protection ability of the scheme against side-channel attacks, the enhanced rotating S-box masking scheme is adopted. No security risk has been detected which proves the validity of the mask scheme. Moreover, this research performs the fault injection attack on white-box implementation. However, the process typically demands substantial time and resources due to its manual testing nature. To optimize the method, we introduce an intelligent fault injection algorithm utilizing a genetic algorithm, which automates the fault injection attack to white-box implementation. This proposed scheme exemplifies intelligence and automation in the testing process. The empirical comparison highlights that the automated fault injection algorithm significantly enhances attack efficiency by 980% when compared to the random parameter search method. © 2023 IEEE.

关键词： Genetic algorithms

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Numerical Simulation of Noise Characteristics of Open Rotor 6

Numerical Simulation of Noise Characteristics of Open Rotor

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6th International Conference on Fluid Mechanics and Industrial Applications, FMIA 2022

作者： Wei, Qing Chen, Zhengwu Tong, Fan Li, Guangming Cui, Panwang Laboratory of Aerodynamic Noise Control China Aerodynamics Research and Development Center Mianyang621000 China School of Shanghai University Shanghai China Hunan Key Laboratory of Mechanical Equipment Health Maintenance Hunan University of Science and Technology Hunan411201 China

In order to investigate the noise characteristics of open rotor, numerical simulation was performed for an open rotor which contains 11 blades for the front row and 9 blades for the rear row. The aerodynamic noise of the open rotor was compared with a single propeller, i.e. the front row propeller. Numerical results show that predicted noise field results agree well with the literature. The noise spectrum of the open rotor is obviously more complex and higher than that of the single propeller. In addition, the contribution of different noise generation mechanisms was studied for the interaction noise. Results show that the blade tip vortex interaction noise and the wake interaction noise are the main noise generation mechanisms while the hub vortex interaction noise contributes less to the interaction noise. Blade tip vortex interaction noise and wake interaction noise need to be paid more attention. The investigation result may help to develop relevant noise reduction techniques for the open rotor. © Published under licence by IOP Publishing Ltd.

关键词： Wind tunnels

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