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Characteristics and suppression of beam distortion in a high repetition rate nanosecond stimulated Brillouin scattering phase conjugation mirror

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High Power Laser Science and Engineering 2024年第2期12卷 69-78页

作者： Yifu Chen bowen tan Duo Jin Bin Chen Zhenxu Bai Kun Wang Yulei Wang Zhiwei Lü School of Astronautics Harbin Institute of TechnologyHarbinChina Center for Advanced Laser Technology Hebei University of TechnologyTianjinChina Hebei Key Laboratory of Advanced Laser Technology and Equipment TianjinChina School of Energy and Environmental Engineering Hebei University of TechnologyTianjinChina

The stimulated Brillouin scattering phase conjugation mirror (SBS-PCM) based on liquid media is widely used in high-power laser systems due to its robust thermal load capacity, high energy conversion efficiency and improved beam quality. Nevertheless, with an increase in the pump repetition rate, thermally-induced blooming and optical breakdown can emerge, leading to distortions in the Stokes beam. In this study, we delved into the thermal effects in liquid SBS-PCMs employing hydrodynamic analysis, establishing a relationship between beam profile distortion and the thermal convection field. We calculated the temperature and convection velocity distribution based on the pump light parameters and recorded the corresponding beam profiles. The intensities of the beam profiles were modulated in alignment with the convection directions, reaching a velocity peak of 2.85 mm/s at a pump pulse repetition rate of 250 Hz. The residual sum of squares (RSS) was employed to quantify the extent of beam profile distortion relative to a Gaussian distribution. The RSS escalated to 7.8, in contrast to 0.7 of the pump light at a pump pulse repetition rate of 500 Hz. By suppressing thermal convection using a high-viscosity medium, we effectively mitigated beam distortion. The RSS was reduced to 0.7 at a pump pulse repetition rate of 500 Hz, coinciding with a twentyfold increase in viscosity, thereby enhancing the beam quality. By integrating hydrodynamic analysis, we elucidated and mitigated distortion with targeted solutions. Our research offers an interdisciplinary perspective on studying thermal effects and contributes to the application of SBS-PCMs in high-repetition-rate laser systems by unveiling the mechanism of photothermal effects.

关键词： beam profile high power high repetition rate stimulated Brillouin scattering phase conjugation mirror thermal convection

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电子鼻在霉变与虫害检测中的研究进展

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兰台世界 2024年第7期 133-140页

作者：孙偲谭博文唐欢馆藏文物有害生物控制研究国家文物局重点科研基地(重庆中国三峡博物馆)

面对霉变与虫害在各领域均可导致严重危害,以及现有检测技术存在不足的难题,电子鼻经过多年发展,在利用挥发性物质检测病虫害方面表现出强大功能,并具备快速、准确、无损检测等优势。本文围绕电子鼻在霉变、虫害检测中的应用,简述了电... 详细信息

面对霉变与虫害在各领域均可导致严重危害,以及现有检测技术存在不足的难题,电子鼻经过多年发展,在利用挥发性物质检测病虫害方面表现出强大功能,并具备快速、准确、无损检测等优势。本文围绕电子鼻在霉变、虫害检测中的应用,简述了电子鼻基本概况,重点介绍了电子鼻在不同领域霉变与虫害检测中的应用现状。此外,基于电子鼻在其他领域的应用,对其在博物馆文物虫霉病害的检测应用进行了讨论分析,并对未来发展趋势进行了展望。

关键词：电子鼻挥发性物质霉变虫害

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山东省国家级水利风景区时空分布及演变

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河南科技 2024年第4期51卷 104-109页

作者：谭博文吴国玺栗淑一华北水利水电大学建筑学院河南郑州450046 许昌学院城市与环境学院河南许昌461000

【目的】基于山东省2001—2022年20批108家国家级水利风景区的地理数据,对山东省国家级水利风景区时空分布及演变进行研究。【方法】运用ArcGis10.8空间分析工具,研究了最邻近指数、Voronoi多边形的变异系数、地理集中指数、标准差椭圆... 详细信息

【目的】基于山东省2001—2022年20批108家国家级水利风景区的地理数据,对山东省国家级水利风景区时空分布及演变进行研究。【方法】运用ArcGis10.8空间分析工具,研究了最邻近指数、Voronoi多边形的变异系数、地理集中指数、标准差椭圆和核密度特征,讨论了水利景区的时空演变规律性。【结果】结果表明:20年间山东省国家级水利景区形成了以鲁中和鲁西两地为核心,向四周发散分布的空间结构,景区分布范围从东北向西南扩散,分布范围逐渐扩大,分布盲点基本消失。【结论】为优化水利风景区空间结构布局和解决景区发展不平衡、不充分问题提供理论依据和实践参考。

关键词：水利风景区空间分布时空演变山东省

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导电炭黑/三元乙丙橡胶复合材料的性能研究

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橡胶工业 2024年第6期71卷 421-426页

作者：许仕强谭博文吴明生青岛科技大学高分子科学与工程学院山东青岛266042

以炭黑N330、炭黑HM3810、导电炭黑DENKA BLACK为填料,研究炭黑/三元乙丙橡胶复合材料的硫化特性、物理性能和导电性能。结果表明:导电炭黑DENKA BLACK填充的混炼胶的F_(L)和Fmax-F_(L)最大,t90最短,炭黑HM3810填充的混炼胶的F_(L)和门... 详细信息

以炭黑N330、炭黑HM3810、导电炭黑DENKA BLACK为填料,研究炭黑/三元乙丙橡胶复合材料的硫化特性、物理性能和导电性能。结果表明:导电炭黑DENKA BLACK填充的混炼胶的F_(L)和Fmax-F_(L)最大,t90最短,炭黑HM3810填充的混炼胶的F_(L)和门尼粘度[ML(1+4)100℃]最小,t_(10)最长;当炭黑用量相同时,炭黑HM3810填充的硫化胶的力学性能最好,导电炭黑DENKA BLACK填充的硫化胶的导电性能最好;随着导电炭黑DENKA BLACK用量的增大,硫化胶的力学性能和导电性能提高;当导电炭黑DENKA BLACK用量为60份时,硫化胶的力学性能和导电性能最好。

关键词：三乙丙橡胶硫化特性物理性能导电性能

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Damage evolution of rock-encased-backfill structure under stepwise cyclic triaxial loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 597-615页

作者： Xin Yu Yuye tan Weidong Song John Kemeny Shengwen Qi bowen Zheng Songfeng Guo Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100089China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing100089China University of Chinese Academy of Sciences Beijing100049China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing100083China Department of Mining and Geological Engineering University of ArizonaTucsonAZ86721USA

Rock-encased-backfill(RB)structures are common in underground mining,for example in the cut-andfill and stoping *** understand the effects of cyclic excavation and blasting activities on the damage of these RB structures,a series of triaxial stepwise-increasing-amplitude cyclic loading experiments was conducted with cylindrical RB specimens(rock on outside,backfill on inside)with different volume fractions of rock(VF=0.48,0.61,0.73,and 0.84),confining pressures(0,6,9,and 12 MPa),and cyclic loading rates(200,300,400,and 500 N/s).The damage evolution and meso-crack formation during the cyclic tests were analyzed with results from stress-strain hysteresis loops,acoustic emission events,and post-failure X-ray 3D fracture *** results showed significant differences between cyclic and monotonic loadings of RB specimens,particularly with regard to the generation of shear microcracks,the development of stress memory and strain hardening,and the contact forces and associated friction that develops along the rock-backfill *** important finding is that as a function of the number of cycles,the elastic strain increases linearly and the dissipated energy increases ***,compared with monotonic loading,the cyclic strain hardening characteristics are more sensitive to rising confining pressures during the initial compaction *** finding is that compared with monotonic loading,more shear microcracks are generated during every reloading stage,but these microcracks tend to be dispersed and lessen the likelihood of large shear fracture *** transition from elastic to plastic behavior varies depending on the parameters of each test(confinement,volume fraction,and cyclic rate),and an interesting finding was that the transformation to plastic behavior is significantly lower under the conditions of 0.73 rock volume fraction,400 N/s cyclic loading rate,and 9 MPa *** the findings have important practical implications on t

关键词： Rock and backfill Triaxial cyclic loading Volume fraction Damage evolution 3D visualization

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Melatonin and dopamine alleviate waterlogging stress in apples by recruiting beneficial endophytes to enhance physiological resilience

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Journal of Integrative Agriculture 2024年第7期23卷 2270-2291页

作者： Yang Cao Peihua Du Yuwei Shang Jiahao Ji Leiqing tan Xue Zhang Jizhong Xu bowen Liang College of Horticulture Hebei Agricultural UniversityBaoding 071001China

Melatonin and dopamine can potentially prevent waterlogging stress in *** current study investigated the mechanism by which melatonin and dopamine alleviate apple waterlogging *** study demonstrated that melatonin and dopamine alleviated waterlogging by removing reactive oxygen species(ROS),and that the nitric oxide(NO)content and nitrate reductase(NR)activity were significantly *** and dopamine were also found to recruit different candidate beneficial endophytes(melatonin:Novosphingobium,Propionivibrio,and Cellvibrio;dopamine:Hydrogenophaga,Simplicispira,Methyloversatilis,Candidatus_Kaiserbacteria,and Humicola),and these endophytes were significantly and positively correlated with plant *** analyses showed that melatonin and dopamine significantly affected the endophytic bacterial and fungal communities under waterlogging *** metabolomic results showed that melatonin and dopamine led to waterlogging resistance by upregulating the abundance of beneficial substances such as amino acids,flavonoids,coumarins,and organic *** addition,melatonin and dopamine regulated the physicochemical properties of the soil,which altered the endophyte community and affected plant *** co-occurrence network demonstrated close and complex relationships among endophytes,metabolites,soil,and the *** results demonstrate that melatonin and dopamine alleviate waterlogging stress in apples by recruiting beneficial endophytes to enhance physiological *** study provides new insights into how melatonin and dopamine alleviate stress and a theoretical basis for synergistic beneficial microbial resistance to waterlogging stress.

关键词： dopamine endophytes Malus hupehensis melatonin metabolomics waterlogging

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SARS-CoV-2 Spike Protein Post-Translational Modification Landscape and Its Impact on Protein Structure and Function via Computational Prediction

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Research 2023年第3期2023卷 757-767页

作者： Buwen Liang Yiying Zhu Wenhao Shi Can Ni bowen tan Shaojun tang The Hong Kong University of Science and Technology(Guangzhou) GuangzhouChina Analysis Center Chemistry DepartmentTsinghua UniversityBeijingChina The Hong Kong University of Science and Technology Hong Kong SARChina

To elucidate the role of post-translational modifications(PTMs)in severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)spike protein’s structure and virulence,we generated a high-resolution map of 87 PTMs using liquid chromatography with tandem mass spectrometry data on the extracted spike protein from SARS-CoV-2 virions and then reconstituted its structure heterogeneity caused by ***,Alphafold2,a high-accuracy artificial intelligence tool to perform protein structure prediction,relies solely on primary amino acid sequence,whereas the impact of PTM,which often modulates critical protein structure and function,is much *** overcome this challenge,we proposed the mutagenesis approach—an in silico,site-directed amino acid substitution to mimic the influence of PTMs on protein structure due to altered physicochemical properties in the post-translationally modified amino acids—and then reconstituted the spike protein’s structure from the substituted sequences by *** the first time,the proposed method revealed predicted protein structures resulting from PTMs,a problem that Alphafold2 has yet to *** an example,we performed computational analyses of the interaction of the post-translationally modified spike protein with its host factors such as angiotensin-converting enzyme 2 to illuminate binding ***,this study suggested the structural analysis of post-translationally modified protein via mutagenesis and deep *** summarize,the reconstructed spike protein structures showed that specific PTMs can be used to modulate host factor binding,guide antibody design,and pave the way for new therapeutic *** code and Supplementary Materials are freely available at https://***/LTZHKUSTGZ/SARS-CoV-2-spike-protein-PTM.

关键词： translational substituted overcome

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A drug-loaded flexible substrate improves the performance of conformal cortical electrodes

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Bio-Design and Manufacturing 2024年第4期7卷 399-412页

作者： Rongrong Qin Tian Li Yifu tan Fanqi Sun Yuhao Zhou Ronghao Lv Xiaoli You bowen Ji Peng Li Wei Huang Frontiers Science Center for Flexible Electronics(FSCFE) Xi’an Institute of Flexible Electronics(IFE)and Xi’an Institute of Biomedical Materials&Engineering(IBME)Northwestern Polytechnical UniversityXi’an 710072China Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Flexible Electronics of Zhejiang Province Ningbo Institute of Northwestern Polytechnical UniversityNingbo 315103China

Cortical electrodes are a powerful tool for the stimulation and/or recording of electrical activity in the nervous ***,the inevitable wound caused by surgical implantation of electrodes presents bacterial infection and inflammatory reaction risks associated with foreign body ***,inflammation of the wound area can dramatically worsen in response to bacterial *** consequences can not only lead to the failure of cortical electrode implantation but also threaten the lives of ***,we prepared a hydrogel made of bacterial cellulose(BC),a flexible substrate for cortical electrodes,and further loaded antibiotic tetracycline(TC)and the anti-inflammatory drug dexamethasone(DEX)onto *** encapsulated drugs can be released from the BC hydrogel and effectively inhibit the growth of Gram-negative and Gram-positive ***,therapeutic cortical electrodes were developed by integrating the drug-loaded BC hydrogel and nine-channel serpentine arrays;these were used to record electrocorticography(ECoG)signals in a rat *** to the controlled release of TC and DEX from the BC hydrogel substrate,therapeutic cortical electrodes can alleviate or prevent symptoms associated with the bacterial infection and inflammation of brain *** approach facilitates the development of drug delivery electrodes for resolving complications caused by implantable electrodes.

关键词： Antibacterial Anti-inflammatory Drug loading Cortical electrodes Bacterial cellulose hydrogel

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Method for Detecting Industrial Defects in Intelligent Manufacturing Using Deep Learning

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Computers, Materials & Continua 2024年第1期78卷 1329-1343页

作者： bowen Yu Chunli Xie College of Mechanical and Electrical Engineering Northeast Forestry UniversityHarbin150040China

With the advent of Industry 4.0,marked by a surge in intelligent manufacturing,advanced sensors embedded in smart factories now enable extensive data collection on equipment *** analysis of such data is pivotal for ensuring production safety,a critical factor in monitoring the health status of manufacturing *** defect detection techniques,typically limited to specific scenarios,often require manual feature extraction,leading to inefficiencies and limited versatility in the overall *** research presents an intelligent defect detection methodology that leverages deep learning techniques to automate feature extraction and defect localization *** proposed approach encompasses a suite of components:the high-level feature learning block(HLFLB),the multi-scale feature learning block(MSFLB),and a dynamic adaptive fusion block(DAFB),working in tandem to extract meticulously and synergistically aggregate defect-related characteristics across various scales and hierarchical *** have conducted validation of the proposed method using datasets derived from gearbox and bearing *** empirical outcomes underscore the superior defect detection capability of our *** demonstrates consistently high performance across diverse datasets and possesses the accuracy required to categorize defects,taking into account their specific locations and the extent of damage,proving the method’s effectiveness and reliability in identifying defects in industrial components.

关键词： Industrial defect detection deep learning intelligent manufacturing

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Time-inconsistent stochastic linear-quadratic control problem with indefinite control weight costs

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Science China Mathematics 2024年第1期67卷 211-236页

作者： Qi Lü bowen Ma School of Mathematics Sichuan UniversityChengdu 610064China

A time-inconsistent linear-quadratic optimal control problem for stochastic differential equations is *** introduce conditions where the control cost weighting matrix is possibly *** such conditions,we obtain a family of closed-loop equilibrium strategies via multi-person differential *** result extends Yong’s work(2017) in the case of stochastic differential equations,where a unique closed-loop equilibrium strategy can be derived under standard conditions(namely,the control cost weighting matrix is uniformly positive definite,and the other weighting coefficients are positive semidefinite).

关键词： linear-quadratic optimal control problem time-inconsistent cost functional generalized Riccati equation indefinite control weight cost closed-loop equilibrium strategy

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