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9th Symposium on Novel Photoelectronic Detection technology and Applications

作者： Lu, Zhang Yunying, Wang Yuanyuan, Guo Fangyuan, Jin Hui, Lin Science and Technology on Underwater Test and Control Laboratory Dalian116013 China

ISBN: (纸本)9781510664432

For the study of the environmental characteristic parameters of typical ocean weak turbulence field, such as temperature and salinity concentration, the intensity distribution of the Gaussian beam propagation in ocean weak turbulence has been obtained by using the temperature-salinity coupling refractive power spectrum model and the theory of random phase screen, and the intensity characteristic has been analyzed by the two-dimensional gray histogram. The simulation results show that the turbulence intensity is an influence on the image characteristic, which contain the brightness and the non-uniformity degree of the image, and the effects of the variable average temperature on the image characteristics are stronger with the increase of the turbulence intensity, and then the effects of the variable average salinity concentration on the image characteristics are small under the typical weak turbulence conditions. © 2023 SPIE.

关键词： Statistical optics

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Pressure Sensitivity Kernel and Travel-Time Gradient for Geoacoustic Parameters Perturbations of Sediment in Shallow Water

Pressure Sensitivity Kernel and Travel-Time Gradient for Geo...

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2022 International Conference on Information Processing in Ocean Science and technology, ICIPOST 2022

作者： Zheng, J. Zhang, X. Ma, Z. Science and Technology on Underwater Test and Control Laboratory Dalian116013 China

In shallow sea, the effect of geoacoustic characteristics of seabed sediments on acoustic propagation cannot be neglected, which is closely related to acoustic detection and seabed inversion. Aiming at the problem of low-frequency acoustic propagation, the sound pressure sensitivity kernel (PSK) and travel-time gradient (TTG) of the shallow low-frequency acoustic field for the geoacoustic parameters of sediment were presented by using normal mode model and perturbation approximation. Combined with the benchmark shallow sea model, the numerical simulation was carried out. The simulation results show that the PSK for the sound velocity of sediment are showing some interference pattern in velocity-range plane and velocity-frequency plane, and its strength is attenuated with the increase of range. TTGs have different sensitivity to the sound velocity of sediment at different range, which is more sensitive at mid-range. The PSK and TTG show some frequency selectivity. © Published under licence by IOP Publishing Ltd.

关键词： Travel time

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Scintillation Characteristics of Gaussian Vortex Beam Propagation in Turbulent Flume

Scintillation Characteristics of Gaussian Vortex Beam Propag...

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2022 International Conference on Information Processing in Ocean Science and technology, ICIPOST 2022

作者： Zhang, L. Wang, Y. Lin, H. Guo, Y. Jin, F. Science and Technology on Underwater Test and Control Laboratory Dalian116013 China

Aiming at the low sensitivity of weak turbulent wake detection of underwater vehicles, studied the laser propagation characteristics in underwater weak turbulence, and then proposed a method based on the statistical characteristics of the scintillation peak of Gaussian vortex beam for detecting the weak turbulence fluctuation. According to the refractive index power spectrum of turbulent flume, the intensity distribution images of Gaussian vortex beam propagating through turbulent flume are simulated by using the random phase screen method, and the scintillation characteristics of Gaussian vortex beam under different conditions are studied. For the simulation results, under the weak turbulence conditions with low refractive index structure coefficient, the average scintillation indexes near the peak value of spot scintillation indexes are obviously higher than those of the whole image. Under the condition that the temperature difference between hot plate and cold plate, between hot plate and water are about 6.4°C and 5.8°C, respectively, the scintillation indexes of the laser propagation intensity image under different temperature gradient (turbulence intensity) are calculated in the experiment. The results show that, the mean values of the scintillation indexes near the spot scintillation peak fluctuate around 1.02 and 1.07, and the mean values in whole image fluctuate around 0.58 and 0.68, respectively, when the temperature gradient is small, which verify the effectiveness of the statistical characteristics of the scintillation peak in detecting weak turbulence. © Published under licence by IOP Publishing Ltd.

关键词： Scintillation

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Vertical array signal recovery method based on normalized virtual time reversal mirror

Vertical array signal recovery method based on normalized vi...

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2022 International Conference on Information Processing in Ocean Science and technology, ICIPOST 2022

作者： Li, P. Zhang, X.G. Zhang, X.Y. Liu, Y. Science and Technology on Underwater Test and Control Laboratory Dalian116013 China Dalian Scientific Test and Control Technology Institute Dalian116013 China

Focusing on the vertical array source signal recovery method, aiming at the estimation deviation caused by environment mismatch in the engineering application of virtual time reversal mirror technology, this paper proposes the normalized virtual time reversal technology through theoretical derivation and analyzes the performance of the virtual time reversal technology under the change of environment and signal-to-noise ratio through simulation. Finally, the practicability of the normalized virtual time reversal method and the effectiveness of model correction are verified through experimental data. The data processing results show that the source level estimation error of vertical array based on normalized virtual time reversal algorithm is less than 5.2dB. In the experimental environment of this paper, the correlation of signal spectral structure recovered by this method is about 5% higher than that by the traditional method. © Published under licence by IOP Publishing Ltd.

关键词： Signal to noise ratio

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Design and Verification of Low Frequency Alternating Magnetic Field Detection Device Based on Unstable Platform

Design and Verification of Low Frequency Alternating Magneti...

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2022 International Conference on Information Processing in Ocean Science and technology, ICIPOST 2022

作者： Zhao, Zhe Jiao, Dawen Hu, Ping Zhang, Jing Cui, Pei Lv, Junjun Science and Technology on Underwater Test and Control Laboratory 16 Binhai Street Dalian China

Low frequency alternating magnetic field is one of the important features for marine magnetic field detection. In order to realize the effective detection of low-frequency alternating magnetic field signal in the marine environment, a low-frequency alternating magnetic field detection device based on unstable platform was designed based on the low-power optical pump magnetometer and signal control processing circuit in this paper. The magnetic field signal can be stored. The power spectrum analysis, line spectrum purification, line spectrum extraction and so on can be processed online, and the processing results are saved and transmitted to the upper computer through serial communication. The test results of laboratory and offshore signal source show that the device has good ability of low frequency alternating magnetic field measurement, analysis and line spectrum extraction. © Published under licence by IOP Publishing Ltd.

关键词： Magnetic fields

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Feature Mining Method Based on Deep Learning for underwater Electric Field Prediction in Marine Environment

Feature Mining Method Based on Deep Learning for Underwater ...

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2023 European Conference on Communication Systems, ECCS 2023

作者： Cui, Pei Jiang, Kaina Yue, Jin Wu, Yuanzhe Fu, Yibo Science and Technology on Underwater Test and Control Laboratory Dalian China Dalian Institute of Measurement and Control Technology Dalian China

ISBN: (纸本)9798350323344

The low-frequency electric field generated by various electromagnetic effects in the ocean overwrites the useful signal in amplitude and frequency, as a background distraction field for electric field detection. Effective electric field characteristic analysis and prediction methods are helpful to improve the environmental adaptability of the equipment and the ability of target detection. The deep learning method is used to mine the characteristics of underwater electric field in the marine environment to improve the prediction accuracy. In order to explore the relationship between seawater environmental parameters and electric field characteristics, parameters including measure time, seawater conductivity, water depth and wave height are used as independent variables, and the amplitude of the underwater electric field in the marine environment is used as the dependent variable. The relationship model between independent variables and dependent variables are established by deep neural network training to realize the prediction of underwater electric field characteristics in the marine environment. The results of 103 training samples and 2 test samples show that the method can effectively identify the test samples, and can be used for the mining and prediction of underwater electric field characteristics, as well as the detection and identification of weak electric field signals submerged in the marine environment. © 2023 IEEE.

关键词： Forecasting

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Influence of Physical Parameters on Echo Spectrum of underwater Target

Influence of Physical Parameters on Echo Spectrum of Underwa...

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2024 OES China Ocean Acoustics, COA 2024

作者： Chen, Yunfei Yu, Dapeng Jia, Bing Wang, Zhenshan Yong, Jintao Wang, Yanjie School of Information and Communication Engineering Dalian University of Technology Dalian China Science and Technology on Underwater Test and Control Laboratory Dalian China

ISBN: (纸本)9798350340297

The elastic scattering features of the underwater target scattering wave depend on the physical parameters of the target, such as the material and structure. Intuitively evaluating the influence of the elastic scattering wave on the characteristics of the whole scattering wave signal is difficult due to the coupling and superposition of the elastic scattering wave and the geometric scattering wave of the target. Based on the different modulation characteristics of broadband echo spectrum produced by target geometry scattering and elastic scattering wave, this paper characterizes and studies the modulation features of echo spectrum and tests the influence of physical parameters on the echo spectrum of underwater target using several simple cylindrical targets with different physical parameters. Moreover, the geometric scattering wave and the elastic scattering wave of the simple target echo are extracted using the fractional Fourier transform (FrFT) domain filtering method, and the influence of physical parameters on the echo spectrum is quantitatively analyzed. © 2024 IEEE.

关键词： Elastic scattering

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Target recognition method based on image simulation technology of underwater target in harsh environment 6

Target recognition method based on image simulation technolo...

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6th Conference on Frontiers in Optical Imaging and technology: Imaging Detection and Target Recognition

作者： Hui, Lin Yunying, Wang Yuanyuan, Guo Fangyuan, Jin Lu, Zhang Meiyu, Sun Science and Technology on Underwater Test and Control Laboratory Dalian116013 China Dalian Maritime University Dalian116026 China

ISBN: (数字)9781510679733

ISBN: (纸本)9781510679726

In order to study the recognition methods of underwater targets in harsh environments and improve the accuracy of image based underwater target recognition, a deep learning based underwater target recognition method in harsh environments was carried out. Propose a simulation method for underwater target harsh environment images based on clearer image samples. The simulation processing mainly includes adding random scale and spatial position obstructions, adding random noise, and obtaining simulated image data. Establish an integrated image dataset, which includes clearer original image data and simulated image data. The recognition results of target recognition models trained on the integrated image dataset have significantly improved compared to the original image dataset. © 2024 SPIE. All rights reserved.

关键词： Deep learning

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Study on Fluctuation Characteristics of Acoustic Signals under Density Layered Fluid Disturbance

Study on Fluctuation Characteristics of Acoustic Signals und...

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2024 OES China Ocean Acoustics, COA 2024

作者： Yong, Jintao Chen, Yunfei Wang, Zhenshan Jia, Bing Wang, Rui Mo, Shiqi Science and Technology on Underwater Test and Control Laboratory Dalian China College of Underwater Acoustic Engineering Harbin Engineering University Harbin China College of Information and Communication Engineering Dalian University of Technology Dalian China

ISBN: (纸本)9798350340297

This study investigates the fluctuation characteristics of acoustic signals in the presence of flow field perturbations within density-stratified fluids through laboratory simulation experiments. A density stratification tank was used to replicate the ocean's stratified environment. The SUBOFF scaled model was employed to mimic the underwater vehicle's navigation process in towing mode. controlled density stratification simulation experiments were conducted to explore the acoustic signal fluctuation characteristics within the wake flow field of the submerged model. Data on the undulation properties of acoustic signals that propagated through the wake flow field of the underwater vehicle were collected. The undulation characteristics of the acoustic signal at two towing speeds and various spatial positions were analyzed. In alignment with the typical marine environment characteristics, this study designed the stratification conditions, the scale of the scaled model, and the towing speed based on the Froude number (Fri) similarity criterion and the geometric similarity law. The analysis of the experimental results indicates that the fluctuating frequency of the acoustic signal amplitude diminishes over time as the wake dissipates post-target passage. Concurrently, the intensity of the high-frequency fluctuation component of the signal also decreases with the dissipation of the wake. © 2024 IEEE.

关键词： Wakes

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Feasibility of low-intensity ultrasound treatment with hydroxylamine to accelerate the initiation of partial nitrification and allow operation under intermittent aeration

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Journal of Environmental Sciences 2024年第5期139卷 446-459页

作者： Jianxiong Jian Xiaojian Liao Zhihua Mo Shoupeng Li Lei Li Shaojin Chen Zhenhua Huang Junhao Chen Wencan Dai Shuiyu Sun Guangzhou Key Laboratory Environmental Catalysis and Pollution Control Guangdong Key Laboratory of Environmental Catalysis and Health Risk ControlSchool of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Guangdong Province Solid Waste Recycling and Heavy Metal Pollution Control Engineering Technology Research Center Guangdong Polytechnic of Environmental Protection EngineeringFoshan 528216China Analysis and Test Center Guangdong University of TechnologyGuangzhou 510006China

Partial nitrification is a key aspect of efficient nitrogen removal,although practically it suf-fers from long start-up cycles and unstable long-term operational *** address these drawbacks,this study investigated the effect of low intensity ultrasound treatment combined with hydroxylamine(NH2OH)on the performance of partial *** showthat compared with the control group,low-intensity ultrasound treatment(0.10W/mL,15 min)combined with NH2OH(5 mg/L)reduced the time required for partial nitrification initiation by 6 days,increasing the nitrite accumulation rate(NAR)and ammonia nitro-gen removal rate(NRR)by 20.4% and 6.7%,respectively,achieving 96.48% ***-tic analysis showed that NH2OH enhanced ammonia oxidation,inhibited nitrite-oxidizing bacteria(NOB)activity and shortened the time required for partial nitrification ***,ultrasonication combined with NH2OH dosing stimulated EPS(extracellular polymeric substances)secretion,increased carbonyl,hydroxyl and amine functional group abundances and enhanced mass *** addition,16S rRNA gene sequencing results showed that ultrasonication-sensitive Nitrospira disappeared from the ultrasound+NH_(2)OH system,while Nitrosomonas gradually became the dominant ***,the results of this study provide valuable insight into the enhancement of partial nitrification start-up during the process of wastewater nitrogen removal.

关键词： Partial nitrification Low-intensity ultrasound Hydroxylamine Ammonia oxidizing bacteria Nitrite oxidizing bacteria

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