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Petroleum Science 2024年第2期21卷 1369-1384页

作者： Chong-Zheng Sun yu-xing li Hui Han Xiao-Yi Geng Xiao Lu College of Energy Storage Technology Shandong University of Science and TechnologyQingdao 266590ShandongChina College of Pipeline and Civil Engineering/Shandong Provincial Key Laboratory of Oil&Gas Storage and Transportation Safety China University of PetroleumQingdao 266580ShandongChina

liquid hydrogen storage and transportation is an effective method for large-scale transportation and utilization of hydrogen energy. Revealing the flow mechanism of cryogenic working fluid is the key to optimize heat exchanger structure and hydrogen liquefaction process(LH2). The methods of cryogenic visualization experiment, theoretical analysis and numerical simulation are conducted to study the falling film flow characteristics with the effect of co-current gas flow in LH2spiral wound heat exchanger.The results show that the flow rate of mixed refrigerant has a great influence on liquid film spreading process, falling film flow pattern and heat transfer performance. The liquid film of LH2mixed refrigerant with column flow pattern can not uniformly and completely cover the tube wall surface. As liquid flow rate increases, the falling film flow pattern evolves into sheet-column flow and sheet flow, and liquid film completely covers the surface of tube wall. With the increase of shear effect of gas-phase mixed refrigerant in the same direction, the liquid film gradually becomes unstable, and the flow pattern eventually evolves into a mist flow.

关键词： Hydrogen liquefaction Spiral wound heat exchanger Flow pattern transition Falling film flow

Research on the falling film flow and heat transfer characteristics of FLNG spiral wound heat exchanger under sea conditions

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Petroleum Science 2022年第3期19卷 1276-1290页

作者： Chong-Zheng Sun liang liu yu-xing li Jian-Lu Zhu College of Pipeline and Civil Engineering/Shandong Provincial Key Laboratory of Oil&Gas Storage and Transportation Safety/Qingdao Key Laboratory of Circle Sea Oil&Gas Storage and Transportation Technology China University of PetroleumQingdaoShandong266580China

As the key equipment of floating liquefied natural gas(FLNG)process,the performance of spiral wound heat exchanger(SWHE)influences operation costs and reliability of the whole system.The sea conditions destroy the falling film flow state of the refrigeration and then affect the heat transfer performance of FLNG SWHE.In order to design and optimize the SWHE,a cryogenic experimental device of FLNG process and a numerical model of falling film flow have been constructed to study the effects of sea conditions on the falling film flow and heat transfer characteristics of SWHE.The cryogenic experimental results show that the pitching conditions have larger effects on the heat transfer performance than yawing.Under the pitching angle of 7°,the natural gas temperature and gaseous refrigerant temperature increase by 3.22°C and 7.42°C,respectively.The flow rates of refrigerant and feed natural gas have a great impact on the heat transfer performance of SWHE under pitching and compound sloshing conditions.When the tilt angle increases to 9°,the tube structure with outer diameter D=8 mm and pipe spacing S=4 mm is recommended to reduce the drying area of the pipe wall surface.

关键词： FLNG Spiral wound heat exchanger Falling film flow Cryogenic heat transfer Sea condition

A comparative study of four nonlinear dynamic methods and their applications in classification of ship-radiated noise

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Defence Technology（防务技术） 2022年第2期18卷 183-193页

作者： yu-xing li Shang-bin Jiao Bo Geng Qing Zhang You-min Zhang School of Automation and Information Engineering Xi’an University of TechnologyXi’an710048China Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi’an University of TechnologyXi’an710048China Department of Mechanical Industrial and Aerospace EngineeringConcordia UniversityMontrealQuebec H3G 1M8Canada

Refined composite multi-scale dispersion entropy(RCMDE),as a new and effective nonlinear dynamic method,has been applied in the field of medical diagnosis and fault diagnosis.In this paper,we first introduce RCMDE into the field of underwater acoustic signal processing for complexity feature extraction of ship radiated noise,and then propose a novel classification method for ship-radiated noise based on RCMDE and k-nearest neighbor(KNN),termed RCMDE-KNN.The results of a comparative experiment show that the proposed RCMDE-KNN classification method can effectively extract the complexity features of ship-radiated noise,and has better classification performance under one and two scales than the other three classification methods based on multi-scale permutation entropy(MPE)and KNN,multi-scale weighted-permutation entropy(MW-PE)and KNN,and multi-scale dispersion entropy(MDE)and KNN,termed MPE-KNN,MW-PE-KNN,and MDE-KNN.It is proved that the RCMDE-KNN classification method for ship-radiated noise is feasible and effective,and can obtain a very high recognition rate.

关键词： Nonlinear dynamic Refined composite multi-scale dispersion entropy(RCMDE) Multi-scale dispersion entropy(MDE) Multi-scale weighted-permutation entropy (MW-PE) Multi-scale permutation entropy(MPE) Classification of ship-radiated noise

A novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise,minimum mean square variance criterion and least mean square adaptive filter

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Defence Technology（防务技术） 2020年第3期16卷 543-554页

作者： yu-xing li Long Wang Faculty of Information Technology and Equipment Engineering Xi'an University of TechnologyXi'an 710048ShaanxiChina School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072ShaanxiChina

Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity of marine environment and the particularity of underwater acoustic channel,noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing.In order to solve the dilemma,we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN),minimum mean square variance criterion(MMSVC) and least mean square adaptive filter(LMSAF).This noise reduction technique,named CEEMDAN-MMSVC-LMSAF,has three main advantages:(i) as an improved algorithm of empirical mode decomposition(EMD) and ensemble EMD(EEMD),CEEMDAN can better suppress mode mixing,and can avoid selecting the number of decomposition in variational mode decomposition(VMD);(ii) MMSVC can identify noisy intrinsic mode function(IMF),and can avoid selecting thresholds of different permutation entropies;(iii) for noise reduction of noisy IMFs,LMSAF overcomes the selection of deco mposition number and basis function for wavelet noise reduction.Firstly,CEEMDAN decomposes the original signal into IMFs,which can be divided into noisy IMFs and real IMFs.Then,MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs.Finally,both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained.Compared with other noise reduction techniques,the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals,which has the better noise reduction effect and has practical application value.CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection,feature extraction,classification and recognition of underwater acoustic signals.

关键词： Underwater acoustic signal Noise reduction Empirical mode decomposition(EMD) Ensemble EMD(EEMD) Complete EEMD with adaptive noise(CEEMDAN) Minimum mean square variance criterion(MMSVC) Least mean square adaptive filter(LMSAF) Ship-radiated noise

A novel signal feature extraction technology based on empirical wavelet transform and reverse dispersion entropy

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Defence Technology（防务技术） 2021年第5期17卷 1625-1635页

作者： yu-xing li Shang-bin Jiao Xiang Gao School of Automation and Information Engineering Xi’an University of TechnologyXi’an710048China School of Electrical Engineering Xi’an University of TechnologyXi’an710048China

Feature extraction is an important part of signal processing,which is significant for signal detection,classification,and recognition.The nonlinear dynamic analysis method can extract the nonlinear characteristics of signals and is widely used in different fields.Reverse dispersion entropy(RDE)proposed by us recently,as a nonlinear dynamic analysis method,has the advantages of fast computing speed and strong anti-noise ability,which is more suitable for measuring the complexity of signal than traditional permutation entropy(PE)and dispersion entropy(DE).Empirical wavelet transform(EWT),based on the theory of wavelet analysis,can decompose a complex non-stationary signal into a number of empirical wavelet functions(EWFs)with compact support set spectrum,which has better decomposition performance than empirical mode decomposition(EMD)and its improved algorithms.Considering the advantages of RDE and EWT,on the one hand,we introduce EWT into the field of underwater acoustic signal processing and fault diagnosis to improve the signal decomposition accuracy;on the other hand,we use RDE as the features of EWFs to improve the signal separability and stability.Finally,we propose a novel signal feature extraction technology based on EWT and RDE in this paper.Experimental results show that the proposed feature extraction technology can effectively extract the complexity features of actual signals.Moreover,it also has higher distinguishing ability for different types of signals than five latest feature extraction technologies.

关键词： Feature extraction Empirical mode decomposition Empirical wavelet transform Permutation entropy Reverse dispersion entropy

The role of Cr content on the corrosion resistance of carbon steel and low-Cr steels in the CO_(2)-saturated brine

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Petroleum Science 2023年第2期20卷 1155-1168页

作者： Cai-lin Wang Hong-Da Guo Jian Fang Sheng-Xian yu Xiao-Qi yue Qi-Hui Hu Cui-Wei liu Jia-Xuan Zhang Rui Zhang Xiu-Sai Xu Yong Hua yu-xing li College of Pipeline and Civil Engineering China University of Petroleum(East China)QingdaoShandong 266580China Shandong Provincial Key Laboratory of Oil&Gas Storage and Transportation Security China University of Petroleum(East China)QingdaoShandong 266580China School of Materials Science and Engineering China University of Petroleum(East China)QingdaoShandong 266580China Corrosion and Integrity Centre Zhejiang JIULI Hi-Tech Metals Co.LtdHuzhouZhejiang 313000China Institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing100083China Pipechina Engineering Technology Innovation Co. LtdTianjin 300000China

The selection of appropriate materials for the transportation pipelines is of vital importance to ensure the safety operation in Carbon Capture,Utilisation and Storage(CCUS).To clarify the effects of Cr content in steel on the resistance against general and localised corrosion,electrochemistry methods combined with pH measurements and various surface analysis techniques were implemented on X65,1Cr,3Cr and 5Cr steel samples in a CO_(2)-saturated solution at 60°C and pH 6.6 during 192 h of immersion.Additionally,thermodynamic and kinetic analyses of the formation of the corrosion products on carbon steel and low-Cr steels were performed.The results show that the general corrosion resistance increased with rising Cr content without the presence of significant corrosion products formation.However,with the formation and development of the corrosion products,the general corrosion resistance reduced with the increase in Cr content.The formation of the compact crystalline FeCO3 on X65 and 1Cr steel surfaces offered superior general corrosion protection,while cannot provide enough localised corrosion protection.By contrast,the double-structural corrosion product layers on 3Cr and 5Cr steels notably suppressed the localised corrosion,but providing poor protection against general corrosion over long immersion periods.This study reveals the contributions of Cr content on general and localised corrosion resistance at various periods,providing references for material selection and evaluation in CO_(2) environments relevant for CCUS.

关键词： CO_(2)corrosion Material selection Cr content CCUS

Improved Cohen-Sutherland algorithm for TGS transmission imaging

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Nuclear Science and Techniques 2023年第6期34卷 91-102页

作者： yu-Cheng Yan Ming-Zhe liu xing-yu li yu-Ting Xiong Yao Tan Zhuo Zuo Lan Chang Cui li State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China The Engineering and Technical College of Chengdu University of Technology Leshan614000China Southwestern Institute of Physics Chengdu610225China Sichuan University of Science and Engineering Zigong643000China

Tomographic gamma scanner(TGS),an advancedγ-ray nondestructive analysis technique,can locate and analyze nuclides in radioactive nuclear waste,and TGS can be categorized into two processes:e.g.,transmission measurement and emission measurement.Specifically,transmission measurements provide the basis for accurate measurement of nonuniform radionuclide content in TGS scanning.The scan data were obtained using the Monte Carlo tool Geant4 simulation,and 25 voxels were divided into five lengths and five widths in a square barrel.In this study,an encoding cropping algorithm based on draped foot vector judgment was adopted to rapidly calculate the voxel trace matrix within a square bucket of nuclear waste,and the transmission images were reconstructed using ordered subset expectation maximization.The results indicated that the cropping speed of the improved coding algorithm was significantly higher than that of the original algorithm,and the relative mean deviation and root-mean-square error between the reconstructed attenuation coefficient and the reference standard value tended to decrease with an increase in the cropped line segments in the voxel;the Pearson correlation coefficient tended to converge to 1.0.The image quality evaluation parameters of the high media-density materials were better than those of the low media-density materials in the above three indexes.The reconstruction effect was relatively poor for more complex filling materials.When there were more than 10 cropped line segments in the voxel,the reconstruction data generally tended to be stable.The graphical trimming algorithm can rapidly calculate the trace matrix of the scanned voxels;it exhibits the advantages of speed and efficiency and can serve as a novel method to solve the trace matrix of TGS nuclear waste transmission scans.

关键词： TGS Cohen-Sutherland Transmission scanning Trace matrix

Surface decoration of mesocarbon microbeads with multifunctional TiNbO4-x@C coating layer as high rate and stable anode of li-ion batteries

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Rare Metals 2024年第5期43卷 2053-2066页

作者： Jia-Mei Lai Zhi-Min Zou yu Bai yu-Tao xing Chun-Hai Jiang Fujian Provincial Key Laboratory of Functional Materials and Applications Institute of Advanced Energy Materials School of Materials Science and Engineering Xiamen University of Technology Shanghai XFH Science and Technology Development Co. Ltd. Fujian XFH New Energy Materials Co. Ltd. Shenzhen XFH Science and Technology Co. Ltd. Laboratório de Microscopia Eletr?nica de Alta Resolu??o Centro de Caracteriza??o Avan?ada Para a Indústria de Petróleo (LaMAR/CAIPE) Universidade Federal Fluminense

Surface modification of graphite anode with electroactive matters has been proven of a more practical strategy in enhancing the performance of li-ion batteries than exploring alternative novel anode materials.Herein,rutile Ti NbO4-xnanoparticles with a tunnel structure are employed as multifunctional decoration substances in combination with a carbon coating layer to improve the rate and cycle properties of mesocarbon microbeads（MCMBs）.As compared to pristine MCMB,the li+diffusion coefficients of the composite anodes are enhanced due to the synergistic effect of Ti Nb O4-x@C.Meanwhile,the overcharge and voltage polarization of the composite anodes at high rate are obviously minimized due to the current sharing effect of the high-potential TiN-bO4-x.Moreover,the amorphous liyTi Nb O4-xconverted from Ti NbO4-xin the initial lithiation process can deliver pseudocapacitive capacity to the composite anodes from the second cycle.All of these functions of Ti NbO4-x@C coating layer have directly contributed to the improved rate and cycle performance of the MCMB/TiNbO4-x@C composite anodes.The one containing 12.0 wt%Ti NbO4-xexhibits a high reversible specific capacity of 118 m Ah·g-1at 10C (1C=372 m A·g-1),together with a high capacity retention of 90.9%after 300 cycles at 3C,which are all much superior to those of pristine MCMB.

关键词： li-ion batteries MCMB TiNbO 4− x Surface decoration Rate capability

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

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Journal of Environmental Sciences 2024年第9期143卷 1-11页

作者： xing-xing Qiao yu-Hang Xu Xiang-Ji liu Sai-Le Chen Zhou Zhong Ya-Feng li Jian Lü Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key Laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment technologies.Herein,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes.Due to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses.This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

关键词： Titanium dioxide Schwertmannite Fenton reaction Environmental endocrine disruptors Photocatalysis

Denoised Internal Models:A Brain-inspired Autoencoder Against Adversarial Attacks

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Machine Intelligence Research 2022年第5期19卷 456-471页

作者： Kai-yuan liu xing-yu li yu-Rui Lai Hang Su Jia-Chen Wang Chun-Xu Guo Hong Xie Ji-Song Guan Yi Zhou School of life Sciences and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Center for Brain Science and Brain-inspired Technology Shanghai 201602China School of life Sciences Tsinghua UniversityBeijing 100084China National Engineering Laboratory for Brain-inspired Intelligence Technology and Application School of Information Science and TechnologyUniversity of Science and Technology of ChinaHefei 230026China Institute of Photonic Chips University of Shanghai for Science and TechnologyShanghai 200093China Centre for Artificial-intelligence Nanophotonics School of Optical-electrical and Computer EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China

Despite its great success,deep learning severely suffers from robustness;i.e.,deep neural networks are very vulnerable to adversarial attacks,even the simplest ones.Inspired by recent advances in brain science,we propose the denoised internal models(DIM),a novel generative autoencoder-based model to tackle this challenge.Simulating the pipeline in the human brain for visual signal processing,DIM adopts a two-stage approach.In the first stage,DIM uses a denoiser to reduce the noise and the dimensions of inputs,reflecting the information pre-processing in the thalamus.Inspired by the sparse coding of memory-related traces in the primary visual cortex,the second stage produces a set of internal models,one for each category.We evaluate DIM over 42 adversarial attacks,showing that DIM effectively defenses against all the attacks and outperforms the SOTA on the overall robustness on the MNIST(Modified National Institute of Standards and Technology)dataset.

关键词： Brain-inspired learning autoencoder robustness adversarial attack generative model