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An electromagnetic semi-active dynamic vibration absorber for thin-walled workpiece vibration suppression in mirror milling

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1315-1334页

作者： Jianghua KONG Bei DING Wei wang zhixia wang Juliang XIAO Hongyun QIU School of Mechanical Engineering Tianjin UniversityTianjin 300350China Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin 300350China Key Laboratory of Modern Mechanisms and Equipment Design of the State Ministry of Education Tianjin UniversityTianjin 300350China

As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local *** address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror *** system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling ***,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between *** resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool *** frequency shift characteristics and vibration absorption performance are comprehensively *** and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface *** results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.

关键词： semi-active dynamic vibration absorber(SADVA) mirror milling selfsensing vibration absorption tuning thin-walled workpiece

Ultra‐low single‐atom Pt on g‐C_(3)N_(4)for electrochemical hydrogen peroxide production

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Carbon Energy 2023年第9期5卷 101-112页

作者： Hongcen Yang Niandi Lu Juntao Zhang Rui wang Shuhao Tian Mengjun wang zhixia wang Kun Tao Fei Ma Shanglong Peng National&Local Joint Engineering Laboratory for Optical Conversion Materials and Technology School of Physical Science and TechnologySchool of Materials and EnergyElectron Microscopy CentreLanzhou UniversityLanzhouChina State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamenChina

Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel ***,the high cost and scarce reserves have restricted their wide ***,it is a challenging task to reduce the amount of Pt as well as ensure good catalytic ***,anchoring of Pt single atoms(0.21 wt‰)with ultra-low content on g-C_(3)N_(4)nanosheets(Pt_(0.21)/CN)has been successfully *** obtained Pt_(0.21)/CN catalyst shows excellent two-electron oxygen reduction(2e-ORR)capability for hydrogen peroxide(H_(2)O_(2)).Compared with CN,its H_(2)O_(2)selectivity increased from 80%to 98%in 0.1M KOH,surpassing those in most of the reported ***,the H_(2)O_(2)production rate of Pt_(0.21)/CN is 767 mmol gcat^(-1)h-1,which is 11.1 times that of *** work may pave the way toward the development of an effective method for the design of noblemetal electrocatalysts with low metal loading and high catalytic activity.

关键词： g‐C_(3)N_(4) hydrogen peroxide platinum single‐atom two‐electron oxygen reduction reaction

Mn,N co-doped Co nanoparticles/porous carbon as air cathode for highly efficient rechargeable Zn-air batteries Hide Author's Information

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Nano Research 2022年第3期15卷 1942-1948页

作者： Hanzhen Zheng Fei Ma Hongcen Yang Xiaogang Wu Rui wang Dali Jia zhixia wang Niandi Lu Fen Ran Shanglong Peng National&Local Joint Engineering Laboratory for Optical Conversion Materials and Technology School of Physical Science and TechnologyLanzhou UniversityLanzhou 730000China State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals School of Material Science and EngineeringLanzhou University of TechnologyLanzhou 730050China

Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are generally catalyzed by precious metals(Pt)and metal oxides(IrO_(2))which still have many shortages including expensive price,poor selectivity and undesirable *** this work,we report a Mn0-doped CoN_(x) on N-doped porous carbon(Mn-CoN_(x)/N-PC)composite from carbonizing metal-organic framework(MOF)derivative as the dual-functional catalyst to boost both the ORR and OER *** to the strong coordination effect between nitrogen and metal elements,the introduction of N can obviously improve the content of Co-N-C active sites for ***,the Mn-doping significantly regulates the electronic structure of the Co element and increases the content of Co^(0) which provide efficient OER active ***-CoN_(x)/N-PC catalyst delivers super dual-functional activity with a half-wave potential of 0.85 V,better than the 20%Pt/C catalyst(0.82 V).When used in Zn-air batteries for testing,Mn-CoN_(x)/N-PC electrocatalyst shows a high power density(145 mW·cm^(−2))and good cycle performance.

关键词： bifunctional electrocatalysts Co-N-C Mn-doped Zn-air batteries

Multi-Dimensional Composite Frame as Bifunctional Catalytic Medium for Ultra-Fast Charging Lithium-Sulfur Battery

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Nano-Micro Letters 2022年第12期14卷 91-105页

作者： Shuhao Tian Qi Zeng Guo Liu Juanjuan Huang Xiao Sun Di wang Hongcen Yang Zhe Liu Xichao Mo zhixia wang Kun Tao Shanglong Peng National and Local Joint Engineering Laboratory for Optical Conversion Materials and Technology School of Materials and EnergyLanzhou UniversityLanzhou 730000People’s Republic of China School of Physical Science and Technology Lanzhou UniversityLanzhou 730000People’s Republic of China

The shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability,which limits the commercial application of Li-S ***,the multi-dimensional composite frame has been proposed as the modified separator(MCCoS/PP)of Li-S battery,which is composed of CoS_(2) nanoparticles on alkali-treated MXene nanosheets and carbon *** experiments and theoretical calculations show that bifunctional catalytic activity can be achieved on the MCCoS/PP *** can not only promote the liquid-solid conversion in the reduction process,but also accelerate the decomposition of insoluble Li_(2)S in the oxidation *** addition,LiPSs shuttle effect has been inhibited without a decrease in lithium-ion transference ***,the MCCoS/PP separator with good LiPSs adsorption capability arouses redistribution and fixing of active substances,which is also beneficial to the rate performance and cycling *** Li-S batteries with the MCCoS/PP separator have a specific capacity of 368.6 mAh g^(−1) at 20C,and the capacity decay per cycle is only 0.033%in 1000 cycles at ***,high area capacity(6.34 mAh cm^(−2))with a high sulfur loading(7.7 mg cm^(−2))and a low electrolyte/sulfur ratio(7.5μL mg^(−1))is achieved.

关键词： MXenes Transition metal sulfides Lithium-ion transference Bifunctional catalysis Reaction kinetics

Energy harvesting and speed sensing with a hybrid rotary generator for self-powered wireless monitoring

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Acta Mechanica Sinica 2024年第9期40卷 116-130页

作者： zhixia wang Hongyun Qiu Xuanbo Jiao Wei wang Qichang Zhang Ruilan Tian Dongxing Cao School of Mechanical Engineering Tianjin UniversityTianjin 300350China Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin 300350China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Mechanics Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China

Real-time onboard health monitoring systems are critical for the railway industry to maintain high service quality and operational ***,the issue with power supplies for monitoring sensors persists,especially for freight trains that lack onboard ***,we propose a hybrid piezoelectric-triboelectric rotary generator(HPT-RG)for energy harvesting and vehicle speed *** HPT-RG incorporates a rotational self-adaptive technique that softens the equivalent stiffness,enabling the piezoelectric non-resonant beam to surpass resonance limitations in a low-frequency *** experiments demonstrate the feasibility of using the HPT-RG as an energy harvesting module to collect the rotational energy of the freight rail transport and power the wireless temperature *** allow multiple monitoring in confined spaces on trains,a triboelectric sensing module is added to the HPT-RG to sense the operation speed and mileage of ***,the generator exhibits favorable mechanical durability under more than 600 h of official testing on the train bogie *** proposed HPT-RG is essential for creating a truly self-powered,maintenance-free,and zero-carbon onboard wireless monitoring system on freight railways.

关键词： Energy harvesting Speed sensing Rotational self-adaptive technique Low-frequency Self-powered wireless monitoring

Emodin alleviates cardiac fibrosis by suppressing activation of cardiac fibroblasts via upregulating metastasis associated protein 3

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Acta Pharmaceutica Sinica B 2019年第4期9卷 724-733页

作者： Dan Xiao Yue Zhang Rui wang Yujie Fu Tong Zhou Hongtao Diao zhixia wang Yuan Lin Zhange Li Lin Wen Xujuan Kang Philipp Kopylov Dmitri Shchekochikhin Yong Zhang Baofeng Yang Department of Pharmacology(State-Province Key Laboratories of Biomedicine-Pharmaceutics of China Key Laboratory of Cardiovascular ResearchMinistry of Education)Harbin Medical UniversityHarbin 150081China Department of Pharmacy The First Affiliated Hospital of Harbin Medical UniversityHarbin 150081China Department of Preventive and Emergency Cardiology Sechenov First Moscow State Medical UniversityMoscow 119991Russian Federation Institute of Metabolic Disease Heilongjiang Academy of Medical ScienceHarbin 150086China Department of Pharmacology and Therapeutics Melbourne School of Biomedical SciencesFaculty of MedicineDentistry and Health SciencesThe University of MelbourneMelbourne 3010Australia

Excess activation of cardiac fibroblasts inevitably induces cardiac fibrosis. Emodin has been used as a natural medicine against several chronic diseases. The objective of this study is to determine the effects of emodin on cardiac fibrosis and the underlying molecular mechanisms. Intragastric administration of emodin markedly decreased left ventricular wall thickness in a mouse model of pathological cardiac hypertrophy with excess fibrosis induced by transaortic constriction(TAC) and suppressed activation of cardiac fibroblasts induced by angiotensin II(AngII). Emodin upregulated expression of metastasis associated protein 3(MTA3) and restored the MTA3 expression in the setting of cardiac fibrosis. Moreover, overexpression of MTA3 promoted cardiac fibrosis;in contrast, silence of MTA3 abrogated the inhibitory effect of emodin on fibroblast activation. Our findings unraveled the potential of emodin to alleviate cardiac fibrosis via upregulating MTA3 and highlight the regulatory role of MTA3 in the development of cardiac fibrosis.

关键词： Emodin Cardiac fibrosis MTA3 Angiotensin Ⅱ Cardiac fibroblast Mouse

基于等效线性化方法的非线性振动能量采集器功率分析

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振动与冲击 2022年第1期41卷 196-205页

作者：李佳诚王志霞王炜王辰天津大学机械工程学院天津300350 天津市非线性动力学与控制重点实验室天津300350 香港理工大学土木与环境工程系中国香港999077

输出功率分析是振动能量采集器结构设计、参数选择的重要依据。有鉴于传统功率分析方法比较复杂,以一类电磁式振动能量采集器为对象,提出了一种新的非线性振动能量采集器功率分析方法,其核心是将非线性振动方程进行等效线性化处理,并借... 详细信息

输出功率分析是振动能量采集器结构设计、参数选择的重要依据。有鉴于传统功率分析方法比较复杂,以一类电磁式振动能量采集器为对象,提出了一种新的非线性振动能量采集器功率分析方法,其核心是将非线性振动方程进行等效线性化处理,并借助传递函数开展功率优化分析。首先,考虑非线性磁力以及基尔霍夫电流定律,建立了通用化的采集器1.5自由度七次非线性机电耦合模型;其次,将动态频率法用于求解该系统控制方程,采用高阶谐波成分替代方程中的非线性项,实现了原有系统控制方程的等效线性化;最后,利用传递函数推导了输出功率表达式,分析等效线性化系统负载,机电耦合系数等因素对于输出功率的影响。研究结果表明:以等效线性化为基础的功率分析,可以有效地克服传统非线性能量采集器系统功率分析方法复杂的问题,具有良好的适用性。

关键词：非线性动态频率法能量采集等效线性化

一类电磁式薄膜振动能量采集器动力学建模与非线性分析

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振动与冲击 2019年第15期38卷 127-133页

作者：王志霞王炜张琪昌天津大学机械工程学院天津300350 天津市非线性动力学与控制重点实验室天津300350

将柔性薄膜和磁铁弹簧相结合,借助振子的阱间运动特性,创新性地设计了一类具有双稳态形式的电磁式振动能量采集器。对系统中的主要非线性因素(具有中心质量的薄膜振子大变形以及非线性形式的磁场力)进行了全面的分析,进而结合虚功原理... 详细信息

将柔性薄膜和磁铁弹簧相结合,借助振子的阱间运动特性,创新性地设计了一类具有双稳态形式的电磁式振动能量采集器。对系统中的主要非线性因素(具有中心质量的薄膜振子大变形以及非线性形式的磁场力)进行了全面的分析,进而结合虚功原理建立了系统的振动控制方程。采用理论、数值模拟和实验等手段进行了动力学分析,证明了控制方程的准确性,也验证了双稳态所表征的阱间运动能够有效地拓宽结构的工作带宽、提高输出功率。研究结果对于类似柔性体结构多稳态能量采集器的设计、优化,理论分析都提供了可供借鉴的参考依据。

关键词：柔性薄膜磁铁弹簧双稳态能量采集器动力学分析

Preparation of 20 (S)-protopanaxadiol PLGA Nanoparticles

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Medicinal Plant 2024年第1期15卷 13-17页

作者： Tao PAN Baifang GONG zhixia wang Hanyu SUN Xuanle YIN Key Laboratory of Molecular Pharmacology and Drug Evaluation of the Ministry of Education(Yantai University) School of PharmacyYantai UniversityYantai 264005China

[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was *** encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.

关键词： 20(S)-protopanaxadiol PLGA nanoparticles Emulsion solvent evaporation method