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Experimental study of suppressing the unbalanced response vibration of rotor system with a G-type integral squeeze film damper

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High Technology Letters 2021年第1期27卷 1-9页

作者： Yan Wei He Lidong zhang Yufei zhang yipeng Jia Xingyun Beijing Key Laboratory of Health Monitoring and Self-Recovery for High-End Mechanical Equipment Beijing University of Chemical TechnologyBeijing 100029P.R.China

Conventional squeeze film dampers have numerous challenges including lock up,bistable response and incoordinate *** order to resolve these nonlinear problems,a novel G-type integral squeeze film damper(GISFD)is proposed in this *** experimental test rig is provided to investigate the rotor system with an unbalanced single *** simulation results show that the structural design of GISFD is reasonable,which can ensure its safe and stable *** influence of different support stiffnesses on the first-order speed of the rotor system is *** results show that GISFD can effectively suppress the unbalanced response vibration of the *** a certain range,it is found that the suppression effect of GISFD increases with the increase in the kinematic viscosity of the damping *** the silicone oil with kinematic viscosity coefficients v=30.0 cm^(2)/s is employed,the vibration reduction of GISFD is approximately 71.51%.Furthermore,the experimental results show that with the increase of the unbalance,there is a linear relationship between the unbalance and the corresponding amplitude of the unbalanced *** is concluded that GISFD has excellent linear damping characteristics and reduces the sensitivity of the rotor system to the unbalanced mass.

关键词： G-type integral squeeze film damper(GISFD) unbalanced response vibration suppression rotor system dynamic characteristic

Dimeric G-quadruplex DNA Structure in the Proximal Promoter of VEGFR-2 Reveals a New Drug Target to Inhibit Tumor Angiogenesis

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Chinese Journal of Chemistry 2022年第18期40卷 2179-2187页

作者： yipeng zhang Wenxian Lan Chunxi Wang Hongjuan Xue Chunyang Cao State Key Laboratory of Bioorganic and Natural Product Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of Sciences345 Lingling RoadShanghai200032 China The Core Facility Centre of CAS Center for Excellence in Molecular Plant Sciences 300 Fengling RoadShanghai200032 China University of Chinese Academy of Sciences No.19(A)Yuquan RoadShijingshan DistrictBeijing100049 China National Center for Protein Science in Shanghai Shanghai Advanced Research InstituteChinese Academy of Sciences333 Kaike RoadShanghai201210 China Collaborative Innovation Center of Chemistry for Life Sciences Chinese Academy of Sciences345 Lingling RoadShanghai200032 China

Vascular endothelial growth factor(VEGF)regulates tumor angiogenesis,which is active on the endothelium via VEGF receptor 2(VEGFR-2).The proximal promoter region of VEGFR-2(termed as VEGFR-2 DNA)is guanine-rich,forming G-quadruplex(G4)***,we demonstrate that VEGFR-2 DNA consists of one symmetrically dimeric 14-mer G4-DNA and one 12-mer sequence-palindromic *** G4-DNA adopts an unprecedented folding with five stacked tetrads linked by four broken *** 5’-end part contains an A-tetrad A^(1)•A^(4)•A^(1’)•A^(4’)and one G-tetrad G^(3)•G^(5)•G^(3’)•G^(5’)with two V-shaped loops and two one-nt edge-type *** 3’-end part includes three G-tetrads G^(10)•G^(6)•G^(10’)•G^(6’),G^(11)•G^(7)•G^(11’)•G^(7’)(central)and G^(12)•G^(8)•G^(12’)•G^(8’)spanned by two double-chain-reversal one-nt(C^(9)or C^(9’))*** G^(13)and G^(13’)stack with G-tetrad G^(12)•G^(8)•G^(12’)•G^(8’).These characteristics make this G4-DNA more stable than reported VEGFR-17T G4 *** dsDNA connects with G4-DNA without any interactions,generating a linear assembly with G4-DNA structural *** studies uncover new structural features of VEGFR-2 DNA as a potential drug target by inhibiting VEGFR-2 expression,thereby tumor angiogenesis.

关键词： NMR VEGFR-2 Structure Tumorangiogenesis G-quadruplex

Numerical investigation on damping coefficient of the integral squeeze film damper

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High Technology Letters 2022年第3期28卷 317-327页

作者： LI Geng HE Lidong JIA Xingyun zhang yipeng WANG Jian Engineering Research Center of Chemical Safety Ministry of Education Beijing University of Chemical TechnologyBeijing 100029P.R.China

The elimination of rotor vibration is usually achieved by applying additional damping to the *** film dampers are widely used in various aerospace and turbine *** research is carried out on flow characteristics in the integral squeeze film dampers(ISFDs).The dynamic response to the operation condition is investigated through the computational fluid dynamics(CFD) model of *** to the large pressure loss at the oil inlet,the oil film force only changes slightly with the increase of oil supply pressure,and the damping increases *** vibration amplitude only affects the film force,but has no effect on the *** oil film force and damping show an upward tendency with the decrease of thickness of the end seal clearance.

关键词： integral squeeze film damper(ISFD) numerical method oil film force damping coefficient

Experimental study on vibration suppression of gear shaft misalignment with ISFD

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High Technology Letters 2019年第1期25卷 17-27页

作者： Lu Kaihua He Lidong zhang yipeng Chen Zhao Yan Wei Beijing Key Laboratory of Health Monitoring and Self-Recovery for High-End Mechanical Equipment Beijing University of Chemical Technology

Misalignment faults in gear systems lead to violent vibration and noise, shortening the life of equipment. The aim of this work is the demonstration of vibration suppression of parallel-misaligned gear shafts using an integral squeeze film damper(ISFD). Using a first grade spur gear in engineering for reference, an open first-grade spur gear system is built and the vibration characteristics of the gear system with rigid supports and ISFD elastic damping supports are studied under different degrees of misalignment. The experimental results show that ISFD supports have excellent damping and vibration attenuation characteristics, which have improved control of the gear system vibration in horizontal, vertical and axial directions under different degrees of misalignment. This work shows that an ISFD structure can effectively suppress vibration of characteristic frequency components and resonance modulation frequency components. The test results provide evidence for the application of ISFD in vibration control of gear shaft misalignment faults in engineering.

关键词： gear shaft parallel misalignment integral squeeze film damper(ISFD) vibration suppression

Highly dispersed NiMo@rGO nanocomposite catalysts fabricated by a two-step hydrothermal method for hydrogen evolution

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International Journal of Minerals,Metallurgy and Materials 2023年第12期30卷 2432-2440页

作者： Duanhao Cao Xiaofeng Ma yipeng zhang La Ta Yakun Yang Chao Xu Feng Ye Jianguo Liu School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China

Exploring and designing a high-performance non-noble metal catalyst for hydrogen evolution reaction(HER)are crucial for the large-scale application of H2 by water ***,novel catalysts with NiMo nanoparticles decorated on reduced graphene oxide(NiMo@r GO)synthesized by a two-step hydrothermal method were *** characterization results showed that the prepared NiMo@r GO-1 had an irregular lamellar structure,and the NiMo nanoparticles were uniformly dispersed on the ***@rGO-1 exhibited outstanding HER performance in an alkaline environment and required only 93 and 180 mV overpotential for HER in 1.0 M KOH solution to obtain current densities of-10 and-50 mA·cm^(-2),*** tests showed that NiMo@rGO-1 had a certain operating stability for32 *** the same condition,the performance of NiMo@rGO-1 can be comparable with that of commercial Pt/C catalysts at high current *** synergistic effect between NiMo particles and lamellate graphene can remarkably promote charge transfer in electrocatalytic *** a result,NiMo@rGO-1 presented the advantages of high intrinsic activity,large specific surface area,and small electrical *** lamellar graphene played a role in dispersion to prevent the aggregation of *** prepared NiMo@rGO-1 can be used in anion exchange membrane water electrolysis to produce *** study provides a simple preparation method for efficient and low-cost water electrolysis to produce hydrogen in the future.

关键词： hydrogen evolution reaction NiMo nanocomposite reduced graphene oxide synergistic effect

Late Quaternary Slip Behavior of the Jinqianghe Fault in the Middle Qilian-Haiyuan Fault Zone,Northeastern Tibetan Plateau

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Acta Geologica Sinica(English Edition) 2022年第3期96卷 825-843页

作者： LIANG Shumin ZHENG Wenjun CHEN Gan zhang Peizhen zhang Dongli BI Haiyun YANG Xue zhang yipeng DUAN Lei LU Bentian Guangdong Provincial Key Laboratory of Geodynamics and Geohazards School of Earth Sciences and EngineeringSun Yat–sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) ZhuhaiGuangdong 519082China State Key Laboratory for Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China

The Qilian-Haiyuan fault zone in the northeastern Tibetan Plateau has been the source of strong earthquakes in the *** its middle segment,the Jinqianghe fault is an important active fault within the Tianzhu seismic gap;however,little is known about its slip *** present a new horizontal displacement distribution along this fault,we used WorldView-2 stereo pairs and unmanned aerial vehicle-based photogrammetry to construct digital elevation models to obtain a detailed tectono-geomorphic interpretation and geomorphic *** offset marker measurements yielded 135 geomorphic displacements and 8 offset *** dating was used to establish the regional age sequence of the geomorphic units in offset fluvial terraces at four study *** displacements and ages linked the offset clusters with the geomorphic unit sequence;the Holocene strike-slip rate of the Jinqianghe fault was estimated to 4.8-5.6 mm/a at~4-12 ka and 2.9-4.7 mm/a from~4 *** recent earthquakes(with a recurrence interval of~1000 years)represent an active seismic period,revealing the potential seismic hazard along this fault because it has not ruptured in the last 1500 years.

关键词： remote sensing offset geomorphology cumulative offset distribution Qilian-Haiyuan fault zone

Polyester-tethered near-infrared fluorophores confined in colloidal nanoparticles:Tunable and thermoresponsive aggregation and biomedical applications

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Aggregate 2023年第2期4卷 193-205页

作者： Cangjie Yang Wei zhang Xin Pang Fan Xiao Sandeep Kumar Kalva yipeng zhang Manojit Pramanik Leilei Tian Gang Liu Mingfeng Wang School of Chemical and Biomedical Engineering Nanyang Technological UniversitySingaporeSingapore School of Science and Engineering The Chinese University of Hong KongShenzhenChina State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics&Center for Molecular Imaging and Translational Medicine School of Public HealthXiamen UniversityXiamenChina School of Materials Science and Engineering South University of Science and TechnologyShenzhenChina Institute of Pharmacology and Toxicology and Institute of Biomedical Engineering Faculty of MedicineUniversity of ZurichZurich CH-8057Switzerland

Intricate assembly of multiple molecular chromophores assisted by protein scaffolds is essential in tuning the optical absorption and energy transfer in the light-harvesting complexes of the photosynthetic systems in ***,it remains a challenge to achieve such structural complexity and functionality in synthetic polymer-chromophore ***,we report a series of polyester-tethered pyrrolopyrrole cyanine derivatives and their colloidal nanoparticles dispersed in water,which show tunable J-or H-aggregation excitonic coupling and near-infrared fluorescence by precise control of the polymer chain lengths,composition,and ***,the optimal fluorescence or photothermal effect of the Jaggregate nanoparticles enables broad applications in fluorescence or photoacoustic bioimaging and phototherapy.

关键词： bioimaging colloids fluorescence polymers self-assembly

Rice FLOURY ENDOSPERM22, encoding a pentatricopeptide repeat protein, is involved in both mitochondrial RNA splicing and editing and is crucial for endosperm development

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Journal of Integrative Plant Biology 2023年第3期65卷 755-771页

作者： Hang Yang Yunlong Wang Yunlu Tian Xuan Teng Zehui Lv Jie Lei Erchao Duan Hui Dong Xue Yang Yuanyan zhang Yinglun Sun Xiaoli Chen Xiuhao Bao Rongbo Chen Chuanwei Gu yipeng zhang Xiaokang Jiang Wenyu Ma Pengcheng zhang Yi Ji Yu zhang Yihua Wang Jianmin Wan State Key Laboratory for Crop Genetics and Germplasm Enhancement Jiangsu Plant Gene Engineering Research CenterNanjing Agricultural UniversityNanjing 210095China National Key Facility for Crop Resources and Genetic Improvement Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China

Most of the reported P-type pentatricopeptide repeat(PPR) proteins play roles in organelle RNA stabilization and splicing. However, P-type PPRs involved in both RNA splicing and editing have rarely been reported, and their underlying mechanism remains largely unknown. Here, we report a rice floury endosperm22(flo22) mutant with delayed amyloplast development in endosperm cells. Map-based cloning and complementation tests demonstrated that FLO22 encodes a mitochondrion-localized P-type PPR *** of FLO22 resulting in defective transsplicing of mitochondrial nad1 intron 1 and perhaps causing instability of mature transcripts affected assembly and activity of complex Ⅰ, and mitochondrial morphology and function. RNA-seq analysis showed that expression levels of many genes involved in starch and sucrose metabolism were significantly down-regulated in the flo22mutant compared with the wild type, whereas genes related to oxidative phosphorylation and the tricarboxylic acid cycle were significantly upregulated. In addition to involvement in splicing as a P-type PPR protein, we found that FLO22 interacted with DYW3, a DYW-type PPR protein, and they may function synergistically in mitochondrial RNA editing. The present work indicated that FLO22 plays an important role in endosperm development and plant growth by participating in nad1 maturation and multi-site editing of mitochondrial messager RNA.

关键词： endosperm development Oryza sativa PPR proteins RNA editing RNA splicing

Research on Voiceprint Recognition Based on Convolutional Neural Network

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Research on Voiceprint Recognition Based on Convolutional Ne...