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Wear monitoring method of water-lubricated polymer thrust bearing based on ultrasonic reflection coefficient amplitude spectrum

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Friction 2023年第5期11卷 685-703页

作者： Changxiong NING Fei HU wu ouyang Xinpin YAN Dongling XU School of Naval Architecture Ocean and Energy Power EngineeringWuhan University of TechnologyWuhan 430063China School of Transportation and Logistics Engineering Wuhan University of TechnologyWuhan 430063China Reliability Engineering Institute National Engineering Research Center for Water Transport SafetyWuhan 430063China Alliance Manchester Business School The University of ManchesterManchester M156PBUK

The water-lubricated thrust bearings of the marine rim-driven thruster(RDT)are usually composed of polymer composites,which are prone to serious wear under harsh working *** is an excellent non-destructive monitoring technology,but polymer materials are characterized by viscoelasticity,heterogeneity,and large acoustic attenuation,making it challenging to extract ultrasonic echo ***,this paper proposes a wear monitoring method based on the amplitude spectrum of the ultrasonic reflection *** effects of bearing parameters,objective function,and algorithm parameters on the identification results are simulated and *** the correlation coefficient and root mean square error as the matching parameters,the thickness,sound velocity,density,and attenuation factor of the bearing are inversed simultaneously by utilizing the differential evolution algorithm(DEA),and the wear measurement system is *** order to verify the identification accuracy of this method,an accelerated wear test under heavy load was executed on a multi-functional vertical water lubrication test rig with poly-ether-etherketone(PEEK)fixed pad and stainless-steel thrust collar as the *** thickness of pad was measured using the high-precision spiral micrometer and ultrasonic testing system,***,the results demonstrate that the thickness identification error of this method is approximately 1%,and in-situ monitoring ability will be realized in the future,which is of great significance to the life prediction of bearings.

关键词： water-lubricated polymer thrust bearings wear monitoring ultrasonic reflection coefficient amplitude spectrum parameter inversion differential evolution

基于虚拟电压矢量模型预测转矩的船舶推进电机控制研究

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舰船科学技术 2024年第7期46卷 98-105页

作者：张聪周永健黄健殷紫栋欧阳武周新聪武汉理工大学交通与物流工程学院湖北武汉430063 武汉理工大学船海与能源动力工程学院湖北武汉430063 国家水运安全工程技术研究中心可靠性工程研究所湖北武汉430063

针对船舶电力推进系统中六相永磁同步电机所采用传统直接转矩控制技术(DTC)仅采用最外围电压大矢量,会产生较大谐波电流并导致转矩波动大的问题,提出基于虚拟电压矢量合成的模型预测转矩控制策略(V-MPTC),利用α-β子空间中同向的大矢... 详细信息

针对船舶电力推进系统中六相永磁同步电机所采用传统直接转矩控制技术(DTC)仅采用最外围电压大矢量,会产生较大谐波电流并导致转矩波动大的问题,提出基于虚拟电压矢量合成的模型预测转矩控制策略(V-MPTC),利用α-β子空间中同向的大矢量和中矢量与z_(1)-z_(2)子空间中反向的小矢量和中矢量恰好对应原理,通过适当地调节一个PWM周期内大矢量和中矢量的占空比,可以使z_(1)-z_(2)子空间中的合成电压矢量幅值为0,实现对电机谐波电流和转矩脉动的抑制。同时为了便于硬件系统实现,进行电压矢量中心化以及采取提前2步的预测方法。仿真结果表明,采用V-MPTC控制策略使系统响应速度有所提高,启动转速超调降低,转矩脉动从0.15 N·m降至0.04 N·m,谐波畸变率从68.92%降至10.85%,验证了该方法在船舶电力推进系统中可提高其控制性能。

关键词：船舶电力推进模型预测转矩控制谐波电流抑制电压矢量

斜航工况下吊舱推进器水动力性能数值及试验研究

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舰船科学技术 2024年第1期46卷 42-47页

作者：董小伟周永健张聪欧阳武梁兴鑫严新平招商局邮轮制造有限公司江苏南通226116 武汉理工大学船海与能源动力工程学院湖北武汉430063 武汉理工大学交通与物流工程学院湖北武汉430063 国家水运安全工程技术研究中心湖北武汉430063

为了探讨吊舱推进器在斜航工况下的水动力性能变化,以某豪华邮轮吊舱推进器为研究对象,采用STAR CCM+软件基于RANS(Reynolds-averaged Navier-Stokes)方法并结合标准速系数和偏转角的水动力性能进行数值模拟。同时,利用拖曳水池和吊舱... 详细信息

为了探讨吊舱推进器在斜航工况下的水动力性能变化,以某豪华邮轮吊舱推进器为研究对象,采用STAR CCM+软件基于RANS(Reynolds-averaged Navier-Stokes)方法并结合标准速系数和偏转角的水动力性能进行数值模拟。同时,利用拖曳水池和吊舱动力仪进行试验研究,并与仿真数据进行比较分析,进一步讨论螺旋桨与吊舱之间的相互作用对水动力性能的影响。结果表明,本文采用的数值模拟方法可较准确预测斜航工况下的水动力性能。螺旋桨推力系数、扭矩系数关于直航工况点对称,其数值随着偏转角的增大而增大;吊舱单元推力系数随着偏转角的增大而减小,吊舱侧向力随着偏转角的增大而增大;螺旋桨单元流场压力和流速在叶梢处达到最大值,吊舱左侧比右侧承担更多的表面压力幅值。

关键词：吊舱推进器偏转角度数值模拟模型试验水动力性能

Lithium-ion and solvent co-intercalation enhancing the energy density of fluorinated graphene cathode

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Journal of Energy Chemistry 2024年第2期89卷 208-215,I0006页

作者： Hao Wang Jie Jiang Pengyu Chen Zhenrui wu Xiaobin Niu Chuying ouyang Jian Liu Liping Wang School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina School of Engineering Faculty of Applied ScienceThe University of British ColumbiaKelowna V1V 1V7Canada 21C Innovation Laboratory Contemporary Amperex Technology Ltd.(21C LAB)Ningde 352100FujianChina

Fluorinated carbons CF_xhold the highest theoretical energy density(e.g.,2180 W h kg^(-1)when x=1)among all cathode materials of lithium primary ***,the low conductivity and severe polarization limit it to achieve its *** this study,we design a new electrolyte,namely 1 M LiBF_(4)DMSO:DOL(1:9 vol.),achieving a high energy density in Li/CF_xprimary *** DMSO with a small molecular size and high donor number successfully solvates Li^(+)into a defined Li^(+)-solvation *** solvated Li^(+)can intercalate into the large-spacing carbon layers and achieve an improved ***,when discharged to 1.0 V,the CF_(1.12)cathode demonstrates a specific capacity of 1944 m A h g^(-1)with a specific energy density of 3793 W h kg^(-1).This strategy demonstrates that designing the electrolyte is powerful in improving the electrochemical performance of CF_(x) cathode.

关键词： Fluorinated carbon Conversion reaction High-energy-density primary battery Li^(+)-solvation structure Solvent co-intercalation

Vibration Reduction Performance of Damping-Enhanced Water-Lubricated Bearing Using Fluid-Saturated Perforated Slabs

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Chinese Journal of Mechanical Engineering 2020年第6期33卷 218-227页

作者： Yong Jin Jianjun Lu wu ouyang Zhenglin Liu Kunsheng Lao Ministry of Education Key Laboratory of High Performance Ship Technology(Wuhan University of Technology)Wuhan430063China School of Energy and Power Engineering Wuhan University of TechnologyWuhan430063China

As the first link element for the transmission of shaft vibration to the pedestal and even to the hull,water-lubricated bearing plays a key role in suppressing *** the porous structure is considered as one of the main methods for improving the wideband vibration and noise reduction performance of materials in many industrial fields,the studies in the field of water-lubricated bearing remain *** enhance vibration reduction performance,a fluid-saturated perforated slab is designed in this study,and via the establishment of a fluid-solid coupled vibration model,the influence law and impact levels were analyzed and verified by simulation and *** results obtained verified that the total vibration amplitude of damping-enhanced stern bearing in the vertical direction was smaller than that of the normal stern bearing,and the reduction amplitude of the characteristic frequency agreed with the optimal value at approximately 0.1 of the volume fraction of the liquid phase when the solid-fluid phase was rubber–***,the increase in fluid fraction did not enhance the damping effect,instead,it unexpectedly reduced the natural frequency of the raw material *** research indicates that the design of the fluid-saturated perforated slab is effective in reducing the transmission of the vibration amplitude from the shaft,and presents the best volume fraction of the liquid phase.

关键词： Water-lubricated stern bearing Fluid-saturated perforated slabs Fluid-salid coupled vibration model

Achieving Ultra-Broad Microwave Absorption Bandwidth Around Millimeter-Wave Atmospheric Window Through an Intentional Manipulation on Multi-Magnetic Resonance Behavior

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Nano-Micro Letters 2024年第9期16卷 291-307页

作者： Chuyang Liu Lu Xu Xueyu Xiang Yujing Zhang Li Zhou Bo ouyang Fan wu Dong‑Hyun Kim Guangbin Ji School of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuPeople’s Republic of China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Physics Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Physics Chungbuk National UniversityCheongju 28644South Korea Department of Chemistry School of ScienceTianjin UniversityTianjin 300072People’s Republic of China

The utilization of electromagnetic waves is rapidly advancing into the millimeter-wave frequency range,posing increasingly severe challenges in terms of electromagnetic pollution prevention and radar ***,existing millimeter-wave absorbers are still inadequate in addressing these issues due to their monotonous magnetic resonance *** this work,rare-earth La^(3+)and non-magnetic Zr^(4+)ions are simultaneously incorporated into M-type barium ferrite(BaM)to intentionally manipulate the multi-magnetic resonance *** leveraging the contrary impact of La^(3+)and Zr^(4+)ions on magnetocrystalline anisotropy field,the restrictive relationship between intensity and frequency of the multi-magnetic resonance is successfully *** magnetic resonance peak-differentiating and imitating results confirm that significant multi-magnetic resonance phenomenon emerges around 35 GHz due to the reinforced exchange coupling effect between Fe^(3+)and Fe^(2+)***,Mosbauer spectra analysis,first-principle calculations,and least square fitting collectively identify that additional La^(3+)doping leads to a profound rearrangement of Zr^(4+)occupation and thus makes the portion of polarization/conduction loss increase *** a consequence,the La^(3+)-Zr^(4+)co-doped BaM achieves an ultra-broad bandwidth of 12.5+GHz covering from 27.5 to 40+GHz,which holds remarkable potential for millimeter-wave absorbers around the atmospheric window of 35 GHz.

关键词： Microwave absorption Ultra-broad bandwidth M-type barium ferrite Magnetocrystalline anisotropy field Multimagnetic resonance

Electroacupuncture ameliorates blood-brain barrier disruption after ischemic stroke through histone acetylation regulation at the matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 2 genes

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Journal of Traditional Chinese Medicine 2024年第4期44卷 734-744页

作者： CHEN Yonglin ouyang Ling MENG Lingling wu Bufan PENG Rou LIU Sitong HOU Dan WANG Yaling JING Xinyue LU Shengfeng FU Shuping Key Laboratory of Acupuncture and Medicine Research of Ministry of Education Nanjing University of Chinese Medicine

OBJECTIVE: To explore whether the regulation of matrix metalloproteinase 9(MMP-9)/tissue inhibitors of MMPs(TIMPs) gene expression through histone acetylation is a possible mechanism by which electroacupuncture(EA)protects blood-brain barrier(BBB) integrity in a middle cerebral artery occlusion(MCAO) rat ***: Male Sprague-Dawley rats were divided into four groups: the sham group, the MCAO group, the MCAO + EA(MEA) group, and the MCAO + EA + HAT inhibitor(HATi) group. The MCAO model was generated by blocking the middle cerebral artery. EA was applied to Baihui(GV20). Samples were collected 1 or 3 d after reperfusion. Neurological function scores and Evans blue extravasation were employed to evaluate the poststroke injury. The effect of EA on MMP-9/TIMPs gene expression was assessed by real-time fluorescence quantitative polymerase chain reaction(RT-qPCR) and chromatin immunoprecipitation(ChIP). RESULTS: Our results showed that EA treatment prominently improved neurological function and ameliorated BBB disruption. The RT-qPCR assay showed that EA reduced the expression of MMP-9 and promoted TIMP-2 mRNA expression, but HATi reversed these effects of EA. In addition, ChIP results revealed that EA decreased the enrichment of H3K9ace/H3K27ace at MMP-9 promoters and notably stimulated the recruitment of H3K9ace/H3K27ace at TIMP-2 promoter. CONCLUSION: EA treatment at Baihui(GV20) regulates the transcription of MMP-9 and TIMP-2 through histone acetylation modification in the acute stage of stroke, which preserves the structural integrity of the BBB in MCAO rats. These findings suggested that the histone acetylation-mediated transcriptional activity of target genes may be a crucial mechanism of EA treatment in stroke.

关键词： blood-brain barrier electroacupuncture histone acetylation matrix metalloproteinase 9 tissue inhibitor of metalloproteinases

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High-repetition-rate and high-power efficient picosecond thin-disk regenerative amplifier

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High Power Laser Science and Engineering 2024年第2期12卷 16-23页

作者： Sizhi Xu Yubo Gao Xing Liu Yewang Chen Deqin ouyang Junqing Zhao Minqiu Liu Xu wu Chunyu Guo Cangtao Zhou Qitao Lue Shuangchen Ruan Key Laboratory of Advanced Optical Precision Manufacturing Technology of Guangdong Higher Education Institutes Sino-German College of Intelligent ManufacturingShenzhen Technology UniversityShenzhenChina Han’s Laser Technology Industry Group Co. Ltd.ShenzhenChina Shenzhen Key Laboratory of Laser Engineering College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenChina Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology College of Engineering PhysicsShenzhen Technology UniversityShenzhenChina

We present an effective approach to realize a highly efficient,high-power and chirped pulse amplification-free ultrafast ytterbium-doped yttrium aluminum garnet thin-disk regenerative amplifier pumped by a zero-phonon line 969 nm laser *** amplifier delivers an output power exceeding 154 W at a pulse repetition rate of 1 MHz with custom-designed 48 pump *** exceptional thermal management on the thin disk through high-quality bonding,efficient heat dissipation and a fully locked spectrum collectively contributes to achieving a remarkable optical-to-optical efficiency of 61%and a near-diffraction-limit beam quality with an M2 factor of *** the best of our knowledge,this represents the highest conversion efficiency reported in ultrafast thin-disk regenerative ***,the amplifier operates at room temperature and exhibits exceptional stability,with root mean square stability of less than 0.33%.This study significantly represents advances in the field of laser amplification systems,particularly in terms of efficiency and average *** advantageous combination of high efficiency and diffraction limitation positions the thin-disk regenerative amplifier as a promising solution for a wide range of scientific and industrial applications.

关键词： high efficiency high power picosecond laser regenerative amplifier thin-disk laser

Semi-implantable device based on multiplexed microfilament electrode cluster for continuous monitoring of physiological ions

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Bio-Design and Manufacturing 2024年第1期7卷 88-103页

作者： Shuang Huang Shantao Zheng Mengyi He Chuanjie Yao Xinshuo Huang Zhengjie Liu Qiangqiang ouyang Jing Liu Feifei wu Hang Gao Xi Xie Hui-jiuan Chen State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument School of Biomedical EngineeringSun Yat-Sen UniversityShenzhen 518107China The First Affiliated Hospital of Sun Yat-Sen University Guangzhou 510080China Pazhou Lab Guangzhou 510335China Institute of Microelectronics of the Chinese Academy of Sciences Beijing 100029China

Modern medicine is increasingly interested in advanced sensors to detect and analyze biochemical *** sensors based on potentiometric methods are a promising platform for monitoring physiological ions in biological *** semi-implantable devices are mainly based on single-parameter *** semi-implantable electrodes for multiparameter sensing have more restrictions on the electrode size due to biocompatibility considerations,but reducing the electrode surface area could potentially limit electrode *** study developed a semi-implantable device system comprising a multiplexed microfilament electrode cluster(MMEC)and a printed circuit board for real-time monitoring of intra-tissue K^(+),Ca^(2+),and Na^(+)*** electrode surface area was less important for the potentiometric sensing mechanism,suggesting the feasibility of using a tiny fiber-like electrode for potentiometric *** MMEC device exhibited a broad linear response(K^(+):2–32 mmol/L;Ca^(2+):0.5–4 mmol/L;Na^(+):10–160 mmol/L),high sensitivity(about 20–45 mV/decade),temporal stability(>2weeks),and good selectivity(>80%)for the above *** vitro detection and in vivo subcutaneous and brain experiment results showed that the MMEC system exhibits good multi-ion monitoring performance in several complex *** work provides a platform for the continuous real-time monitoring of ion fluctuations in different situations and has implications for developing smart sensors to monitor human health.

关键词： Multiplexed microfilament electrode cluster Physiological ion sensing Subcutaneous and brain experiment Wearable platform for multi-ion detection Continuous real-time monitoring system