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Extraction of pipeline defect feature based on variational mode and optimal singular value decomposition

Petroleum Science 2023年第2期20卷 1200-1216页

作者： Min Zhang Yan-Bao Guo Zheng Zhang ren-bi he De-Guo Wang Jin-Zhong Chen Tie Yin College of Mechanical and Transportation Engineering China University of PetroleumBeijing102249China China Special Equipment Inspection and Research Institute Beijing100029China China Petroleum and Natural Gas Pipeline Research Institute Co.LTD LangfangHebei 065000China

Because the magnetic signal information of pipeline defects obtained by magnetic flux leakage detection contains interference signals, it is difficult to accurately extract the features. Therefore, a novel pipeline defect feature extraction method based on VMD-OSVD (variational modal decomposition - optimal singular value decomposition) is proposed to promote the signal to noise ratio (SNR) and reduce aliasing in the frequency domain. By using the VMD method, the sampled magnetic signal is decomposed, and the optimal variational mode is selected according to the rate of relative change (VMK) of Shannon entropy (SE) to reconstruct the signal. After that, SVD algorithm is used to filter the reconstructed signal again, in which the H-matrix is optimized with the phase-space matrix to enhance SNR and decrease the frequency domain aliasing. The results show that the method has excellent denoising ability for defect magnetic signals, and SNR is increased by 21.01%, 24.04%, 0.96%, 32.14%, and 20.91%, respectively. The improved method has the best denoising effect on transverse mechanical scratches, but a poor denoising effect on spiral welding position. In the frequency domain, the characteristics of different defects are varied, and their corresponding frequency responses are spiral weld corrosion > transverse mechanical cracking > girth weld > deep hole > normal pipe. The high-frequency band is the spiral weld corrosion with f1 = 153.37 Hz. The low-frequency band is normal with f2 = 1 Hz. In general, the VMD-OSVD method is able to improve the SNR of the signal and characterize different pipe defects. And it has a certain guiding significance to the application of pipeline inspection in the field of safety in the future.

关键词： VMD method VMK SVD algorithm Phase space matrix Signal characteristics Pipeline defect Reconstruct

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T cell interactions with microglia in immune-inflammatory processes of ischemic stroke

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Neural Regeneration Research 2025年第5期20卷 1277-1292页

作者： Yuxiao Zheng Zilin ren Ying Liu Juntang Yan Congai Chen Yanhui he Yuyu Shi Fafeng Cheng Qingguo Wang Changxiang Li Xueqian Wang School of Traditional Chinese Medicine Beijing University of Chinese MedicineBeijingChina Library Beijing University of Chinese MedicineBeijingChina Dongzhimen Hospital Beijing University of Chinese MedicineBeijingChina

The primary mechanism of secondary injury after cerebral ischemia may be the brain inflammation that emerges after an ischemic stroke,which promotes neuronal death and inhibits nerve tissue *** the first immune cells to be activated after an ischemic stroke,microglia play an important immunomodulatory role in the progression of the *** an ischemic stroke,peripheral blood immune cells(mainly T cells)are recruited to the central nervous system by chemokines secreted by immune cells in the brain,where they interact with central nervous system cells(mainly microglia)to trigger a secondary neuroimmune *** review summarizes the interactions between T cells and microglia in the immune-inflammatory processes of ischemic *** found that,during ischemic stroke,T cells and microglia demonstrate a more pronounced synergistic ***1,Th17,and M1 microglia can co-secrete proinflammatory factors,such as interferon-γ,tumor necrosis factor-α,and interleukin-1β,to promote neuroinflammation and exacerbate brain ***2,Treg,and M2 microglia jointly secrete anti-inflammatory factors,such as interleukin-4,interleukin-10,and transforming growth factor-β,to inhibit the progression of neuroinflammation,as well as growth factors such as brain-derived neurotrophic factor to promote nerve regeneration and repair brain *** interactions between microglia and T cells influence the direction of the subsequent neuroinflammation,which in turn determines the prognosis of ischemic stroke *** trials have been conducted on the ways to modulate the interactions between T cells and microglia toward anti-inflammatory communication using the immunosuppressant fingolimod or overdosing with Treg cells to promote neural tissue repair and reduce the damage caused by ischemic ***,such studies have been relatively infrequent,and clinical experience is still *** summary,in ischemic stroke,T cell subsets and activated micro

关键词： brain immune inflammation interaction ischemic stroke mechanism microglia neuron secondary injury T cells

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乳铁蛋白减轻肠道功能障碍的研究进展

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食品科学 2025年第2期46卷 317-326页

作者：李懿任鑫鑫王勤贺晓云中国农业大学食品科学与营养工程学院北京100083 中国农业大学动物科学技术学院北京100083

肠道屏障保持机体内环境稳定,当肠黏膜受损、肠道细胞间紧密连接被破坏和肠道菌群失调时会引发多种疾病。天然活性蛋白在肠道屏障修复中起着关键作用,乳铁蛋白是存在于哺乳动物乳汁中的糖蛋白,具有抗氧化、抗炎和抗菌等多种生物学功能... 详细信息

肠道屏障保持机体内环境稳定,当肠黏膜受损、肠道细胞间紧密连接被破坏和肠道菌群失调时会引发多种疾病。天然活性蛋白在肠道屏障修复中起着关键作用,乳铁蛋白是存在于哺乳动物乳汁中的糖蛋白,具有抗氧化、抗炎和抗菌等多种生物学功能。大量研究表明乳铁蛋白能够增强肠道紧密连接蛋白水平,促进肠细胞生长发育,下调炎症因子表达,调节免疫反应和肠道微生物多样性,参与维持肠道屏障稳态。本文对乳铁蛋白缓解肠道屏障功能障碍研究进展展开综述,有助于了解乳铁蛋白在肠道损伤中的作用机制,为乳铁蛋白制品干预肠道疾病提供参考。

关键词：乳铁蛋白肠道屏障生理活性肠道微生物

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Sulfolane‑Based Flame‑Retardant Electrolyte for High‑Voltage Sodium‑Ion Batteries

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Nano-Micro Letters 2025年第2期17卷 498-516页

作者： Xuanlong he Jie Peng Qingyun Lin Meng Li Weibin Chen Pei Liu Tao Huang Zhencheng Huang Yuying Liu Jiaojiao Deng Shenghua Ye Xuming Yang Xiangzhong ren Xiaoping Ouyang Jianhong Liu biwei Xiao Jiangtao Hu Qianling Zhang Graphene Composite Research Center College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China Center of Electron Microscopy State Key Laboratory of Silicon and Advanced Semiconductor MaterialsSchool of Materials Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China GRINM(Guangdong)Research Institute for Advanced Materials and Technology FoshanGuangdong 528051People’s Republic of China College of Energy Engineering Zhejiang UniversityHangzhouZhejiang 310027People’s Republic of China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105People’s Republic of China Shenzhen Eigen-Equation Graphene Technology Co.Ltd Shenzhen 518000People’s Republic of China

Sodium-ion batteries hold great promise as next-generation energy storage ***,the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of *** particular,an unstable cathode–electrolyte interphase(CEI)leads to successive electrolyte side reactions,transition metal leaching and rapid capacity decay,which tends to be exacerbated under high-voltage ***,constructing dense and stable CEIs are crucial for high-performance *** work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether,which exhibited excellent oxidative stability and was able to form thin,dense and homogeneous *** excellent CEI enabled the O3-type layered oxide cathode NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)(NaNMF)to achieve stable cycling,with a capacity retention of 79.48%after 300 cycles at 1 C and 81.15%after 400 cycles at 2 C with a high charging voltage of 4.2 *** addition,its nonflammable nature enhances the safety of *** work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes.

关键词： Sodium-ion batteries Sulfolane-based electrolyte High voltage Layered oxide cathode Flame retardant

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Surface Integrity of Inconel 738LC Parts Manufactured by Selective Laser Melting Followed by High-speed Milling

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 65-79页

作者： Guanhui ren Sai Guo bi Zhang Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen518055China Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials Shenzhen518055China Research and Development Department Shenzhen Xinjinquan Precision Techonology Co.Ltd.Shenzhen518055China School of Mechanical Engineering Shandong UniversityJinan250061China

This study is concerned with the surface integrity of Inconel 738LC parts manufactured by selective laser melting(SLM)followed by high-speed milling(HSM).In the investigation process of surface integrity,the study employs ultradepth three-dimensional microscopy,laser scanning confocal microscopy,scanning electron microscopy,electron backscatter diffractometry,and energy dispersive spectroscopy to characterize the evolution of material microstructure,work hardening,residual stress coupling,and anisotropic effect of the building direction on surface integrity of the *** results show that SLM/HSM hybrid manufacturing can be an effective method to obtain better surface quality with a thinner machining metamorphic ***-speed machining is adopted to reduce cutting force and suppress machining heat,which is an effective way to produce better surface mechanical properties during the SLM/HSM hybrid manufacturing *** general,high-speed milling of the SLM-built Inconel 738LC samples offers better surface integrity,compared to simplex additive manufacturing or casting.

关键词： Surface integrity Inconel 738LC Selective laser melting High-speed milling

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Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 224-239页

作者： Sai Guo Guanhui ren bi Zhang Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhenGuangdongChina State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityKowloonHong KongChina

New materials and manufacturing technologies require applicable non-destructive techniques for quality assurance so as to achieve better *** study comprehensively investigated the effect of influencing factors includ-ing excitation frequency,lift-off distance,defect depth and size,residual heat,and surface roughness on the defect EC signals of an Inconel 738LC alloy produced by selective laser melting(SLM).The experimental investigations recorded the impedance amplitude and phase angle of EC signals for each defect to explore the feasibility of detecting sub-surface defects by merely analyzing these two key ***,this study revealed preliminary qualitative and roughly quantitative relationships between influencing factors and corresponding EC signals,which provided a prac-tical reference on how to quantitively inspect subsurface defects using eddy current testing(ECT)on SLMed parts,and also made solid progress toward on-line ECT in additive/subtractive hybrid manufacturing(ASHM)for fabricating SLMed parts with enhanced quality and better performance.

关键词： Eddy current testing Subsurface defect Additive/subtractive hybrid manufacturing Selective laser melting Inconel 738LC alloy

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Utility Aware Offloading for Mobile-Edge Computing

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Tsinghua Science and Technology 2021年第2期26卷 239-250页

作者： Ran bi Qian Liu Jiankang ren Guozhen Tan School of Computer Science and Technology Dalian University of TechnologyDalian 116024China

Mobile-edge computing casts the computation-intensive and delay-sensitive applications of mobile devices onto network *** offloading incurs extra communication latency and energy cost,and extensive efforts have focused on offloading *** metrics of the system utility are defined to achieve satisfactory quality of ***,most existing works overlook the balance between throughput and *** study investigates the problem of finding an optimal offloading scheme in which the objective of optimization aims to maximize the system utility for leveraging between throughput and *** on Karush-Kuhn-Tucker condition,the expectation of time complexity is analyzed to derive the optimal scheme.A gradient-based approach for utility-aware task offloading is ***,we provide an increment-based greedy approximation algorithm with 1+1/(e-1)*** results show that the proposed algorithms can achieve effective performance in utility and accuracy.

关键词： utility approximation algorithm quality of experience mobile edge computing

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Attribute Reduction with Rough Set in Context-Aware Collaborative Filtering

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Chinese Journal of Electronics 2017年第5期26卷 973-980页

作者： he Ming ren Wanpeng College of Computer Science Beijing University of Technology

The problem of different contextual information to influence the user-item-context interactions at varying degrees in context-aware recommender systems is *** improve the performance accuracy,we develop a novel attribute reduction algorithm in order to effectively extract the core contextual information using rough *** combine collaborative filtering with contextual information significance to generate more accurate *** experimentally evaluate our approach on UCI machine learning repository and two real world data *** results demonstrate that our proposed approach outperforms existing state-of-theart context-aware recommendation methods.

关键词： Context-aware recommendation systems(CARS) Collaborative filtering Rough set

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Mesomorphous structure change by tail chain number in ionic liquid crystalline complexes of linear polymer and amphiphiles

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Chinese Chemical Letters 2011年第11期22卷 1375-1378页

作者： Zhi Yu Cheng bi Ye ren Shu Ying he Xin Xing Liu Zhen Tong Research Institute of Materials Science South China University of Technology Guangzhou 510640 China

Three polymer-amphiphile complexes were prepared by combining poly（allylamine hydrochloride）（PAH） with the potassium salt of mono-,di-,and trisubstituted benzoic acid dendrons（4-octyloxybenzoic acid,3,5-dioctyloxybenzoic acid,and 3,4,5- trioctyloxybenzoic acid）.The solid structure and properties were monitored with FT-IR,XRD,TG,DSC,and polarized optical microscope（POM）.Difference in the tail chain number of the dendritic amphiphile induced two different mesomorphous structures： lamella for the mono-,disubstituted dendron containing complexes and hexagonal column for the trisubstituted dendron containing *** corresponded to the ionic thermotropic liquid crystal SmA andΦ_h phases,*** finding is significant for design of functional nanostructures based on the ionic complexation of polymers and amphiphiles.

关键词： Polymer-amphiphile complex Poly(allylamine hydrochloride) Dendritic amphiphile Ionic thermotropic liquid crystal

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A Tree-valued Markov Process Associated with an Admissible Family of Branching Mechanisms

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Acta Mathematica Sinica,English Series 2019年第1期35卷 135-160页

作者： Hong Wei bi Hui he School of Insurance and Economics University of International Business and EconomicsBeijing 100029.P.R.China Laboratory of Mathematics and Complex Systems School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

Let E■R be an interval. By studying an admissible family of branching mechanisms{ψt,t ∈E} introduced in Li [Ann. Probab., 42, 41-79(2014)], we construct a decreasing Levy-CRT-valued process {Tt, t ∈ E} by pruning Lévy trees accordingly such that for each t ∈E, Tt is a ψt-Lévy tree. We also obtain an analogous process {Tt*,t ∈E} by pruning a critical Levy tree conditioned to be infinite. Under a regular condition on the admissible family of branching mechanisms, we show that the law of {Tt,t ∈E} at the ascension time A := inf{t ∈E;Tt is finite} can be represented by{Tt*,t∈E}.The results generalize those studied in Abraham and Delmas [Ann. Probab., 40, 1167-1211(2012)].

关键词： Pruning admissible family branching process random tree Lévy tree tree-valued process ascension process

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