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Heave-Roll-Pitch Coupled Nonlinear Internal Resonance Response of a Spar Platform Considering Wave and Vortex Exciting Loads

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Journal of Ocean University of China 2017年第2期16卷 209-222页

作者： LI Wei TANG Yougang liu liqin liu Shuxiao CAI Runbo State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072P.R.China School of Civil Engineering Tianjin UniversityTianjin 300072P.R.China

Many studies have been done on the heave-pitch unstable coupling response for a spar platform by a 2-DOF *** fact,in addition to the heave and pitch which are in one plane,the nonlinear unstable motion will also occur in *** the results of the experiments,the unstable roll motion plays a dominant role in the motion of a spar platform which is much stronger than that of *** objective of this paper is to study 3-DOF coupling response performance of spar platform under wave and vortex-induced *** nonlinear coupled equations in heave,roll and pitch are established by considering time-varying wet surface and *** first order steady-state response is solved by multi-scales method when the incident wave frequency approaches the heave natural *** integration of the motion equations has been performed to verify the first-order perturbation *** results are confirmed by model *** is a saturation phenomenon associated with heave mode in 3-DOF systems and all extra energy is transferred to roll and *** is observed that sub-harmonic response occurs in roll and pitch when the wave force exceeds a certain *** energy distribution in roll and pitch is determined by the initial value and damping characteristics of roll and *** energy transfers from heave to pitch and then transfers from pitch to *** to the influence of the low-frequency vortex-excited force,the response of roll is more complicated than that of pitch.

关键词： spar platform 3-DOF nonlinear equations multiple scales sub-harmonic response energy infiltration

One-step synthesis of fluorescent hydroxyls-coated carbon dots with hydrothermal reaction and its application to optical sensing of metal ions

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Science China Chemistry 2011年第8期54卷 1342-1347页

作者： liu liqin LI YuanFang ZHAN Lei liu Yue HUANG ChengZhi Education Ministry Key Laboratory on Luminescence and Real-Time Analysis College of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China CoUege of Pharmaceutical Sciences Southwest University Chongqing 400715 China

Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).

关键词： carbon dots fluorescence quantum yield cytotoxicity metal ions

The Nonlinear Bifurcation and Chaos of Coupled Heave and Pitch Motions of a Truss Spar Platform

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Journal of Ocean University of China 2015年第5期14卷 795-802页

作者： HUANG Lei liu liqin liu Chunyuan TANG Yougang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University

This paper presents the results from a numerical study on the nonlinear dynamic behaviors including bifurcation and chaos of a truss spar platform. In view of the mutual influences between the heave and the pitch modes, the coupled heave and pitch motion equations of the spar platform hull were established in the regular waves. In order to analyze the nonlinear motions of the platform, three-dimensional maximum Lyapunov exponent graphs and the bifurcation graphs were constructed, the Poincare maps and the power spectrums of the platform response were calculated. It was found that the platform motions are sensitive to wave fre- quency. With changing wave frequency, the platform undergoes complicated nonlinear motions, including 1/2 sub-harmonic motion, quasi-periodic motion and chaotic motion. When the wave frequency approaches the natural frequency of the heave mode of the platform, the platform moves with quasi-periodic motion and chaotic motional temately. For a certain range of wave frequencies, the platform moves with totally chaotic motion. The range of wave frequencies which leads to chaotic motion of the platform increases with increasing wave height. The three-dimensional maximum Lyapunov exponent graphs and the bifurcation graphs reveal the nonlinear motions of the spar platform under different wave conditions.

关键词： truss spar platform coupled heave and pitch quasi-periodic motion chaotic motion 1/2 sub-harmonic motion maximum Lyapunov exponent bifurcation graph

Two complete mitogenomes of Ocypodoidea(Decapoda: Brachyura), Cleistostoma dilatatum(Camptandriidae) and Euplax sp.(Macrophthalmidae) and its phylogenetic implications

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Acta Oceanologica Sinica 2023年第4期42卷 81-92页

作者： Ying Zhang Liming Wei Bingjian liu liqin liu Zhenming Lü Li Gong National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization National Engineering Research Center for Facilitated Marine AquacultureZhoushan 316022China Marine Science and Technology College Zhejiang Ocean UniversityZhoushan 316022China

Complete mitochondrial genomes(mitogenomes) can provide useful information for phylogenetic relationships,gene rearrangement, and molecular evolution. In the present study, two newly sequenced mitogenomes of Ocypodoidea(Cleistostoma dilatatum and Euplax sp.) were reported for the first time, which are 15 444 bp and16 129 bp in length, respectively. Cleistostoma dilatatum is the first species in the family Camptandriidae whose complete mitogenome was sequenced. Each mitogenome contains an entire set of 37 genes and a putative control region, but their gene arrangements are largely different. Tandem duplication and random loss model is proposed to account for their gene arrangements. Comparative genomic analyses of 19 mitogenomes clustering in one branch reveal that 18 of them shared the same gene rearrangement, while that of C. dilatatum mitogenome was consistent with the ancestral gene arrangement of Brachyura. The dN/dS ratio analysis shows that all PCGs are evolving under purifying selection. Phylogenetic analyses show that all Macrophalmidae species cluster together as a group, and then form a sister clade with Camptandriidae. Moreover, the polyphyly of three superfamilies(Ocypodoidea, Eriphioidea, and Grapsoidea) is reconfirmed. These findings help to confirm the phylogenetic position of Camptandriidae, as well as provide new insights into the phylogeny of Brachyura.

关键词： Camptandriidae Macrophthalmidae mitogenome gene rearrangement phylogenetic analysis

Coupled Time-Domain Investigation on a Vertical Axis Wind Turbine Supported on a Floating Platform

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Journal of Ocean University of China 2023年第2期22卷 365-376页

作者： CUI Jianhui ZHAI Yongjian GUO Ying DENG Wanru liu liqin Maritime College Tianjin University of TechnologyTianjin 300384China State Key Laboratory of Hydraulic Engineering Simulation and Safety School of Civil EngineeringTianjin UniversityTianjin 300072China

The dynamic responses of a floating vertical axis wind turbine(VAWT)are assessed on the basis of an aero-hydro-mooring coupled *** aerodynamic loads on the rotor are acquired with double-multiple stream tube ***-and second-order wave loads are calculated on the basis of 3D potential *** mooring loads are simulated by catenary *** coupled model is established,and a numerical code is programmed to investigate the dynamic response of the semi-submersible VAWT.A model test is then conducted,and the numerical code is validated considering the hydrodynamic performance of the floating *** responses of the floating VAWT are studied through the numerical simulation under the sea states of wind and regular/irregular *** effects of the second-order wave force on the motions are also *** show that the slow-drift responses in surge and pitch motions are significantly excited by the second-order wave ***,the effect of foundation motion on aerodynamic loads is *** normal and tangential forces of the blades demonstrate a slight increase due to the coupling effect between the buoy motion and the aerodynamic loads.

关键词： offshore wind power semi-submersible floating foundation vertical axis wind turbine numerical calculation model test

Structural Strength Analysis of a Tri-Floater Floating Foundation for Offshore VAWT

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Journal of Ocean University of China 2018年第4期17卷 753-762页

作者： liu liqin ZHAO Haixiang XU Wanhai YUAN Rui GUO Ying State Kev Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Vertical axis wind turbines(VAWTs) are advantageous for the development of large-scale offshore wind power because the drive system is located at the bottom of the turbine. This study investigates the structural strength of a tri-floater floating foundation supporting a 2.6 MW Darrieus VAWT. Finite element models of the floating foundation were developed using space plate-beam elements. The environmental loads, such as the aerodynamic loads, static wind loads, and wave-current loads, were considered. The general strengths of the floating foundation were calculated for the normal operating case(a cut-out wind speed of 25 m s^(-1) and blade rotation of 12 r min^(-1) were used to analyze the most unfavorable loads) and an extreme case(wind speed of 40 m s^(-1) and parked blades), and the weak components of the structure were analyzed. The results show that the floating foundation meets the strength requirements and the structural stress is highest when the wave, wind, and current are in a collinear direction. The main and secondary supporting bars transmit the loads between the stand columns and the tower foundation, and their stresses are higher than those in the other components. In the actual design, these supporting bars should be strengthened. The aerodynamic loads are very important and should be considered in the structural strength analysis of the floating foundation and the floating wind turbine system.

关键词： vertical axis wind turbine tri-floater floating foundation strength analysis finite element method structural stress

CFD Simulation of the Vertical Motion Characteristics of the Moonpool Fluid for the Truss Spar

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Journal of Marine Science and Application 2014年第1期13卷 92-98页

作者： Bin Wang liqin liu Yougang Tang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University

The research purpose of this paper is to estimate the impacts of the parameters of the guide plate on the vertical motion characteristics of the moonpool fluid. With the volume of fluid(VOF) method, three-dimensional models of the moonpool fluid motions of the truss spar platform are established. Simulation results are then presented for the moonpool forced oscillation by employing the dynamic mesh method and user-defined functions in FLUENT. The motions of the moonpool fluid and the loads on the guide plates are obtained for both cases of square-ring and crisscross. The results show that the shape and area of the guide plate at the bottom of the moonpool have a significant impact on the physical parameters of the moonpool, including the load on the moonpool guide plate, motion form of the moonpool fluid and the mass flow rate.

关键词： vertical motion VOF truss spar platform moonpool fluid guide plate CFD

Complete Mitochondrial Genome of Myra affinis(Decapoda:Brachyura:Leucosiidae)and Its Phylogenetic Implications for Brachyura

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Journal of Ocean University of China 2022年第4期21卷 987-997页

作者： ZHANG Ying MENG Lei MIAO Zengliang WEI Liming liu Bingjian liu liqin GONG Li LÜZhenming Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization National Engineering Research Center forFacilitated Marine AquacultureMarine Science and Technology CollegeZhejiang Ocean UniversityZhoushan 316022China School of Fishery Zhejiang Ocean UniversityZhoushan 316022China

Knowledge of complete mitochondrial genomes(mitogenomes)can help understand the molecular evolution and phylogenetic relationships of various *** date,the phylogenetic status of Leucosiidae within Brachyura remains unresolved because of the limited number of mitogenomes *** the present study,the complete mitogenome of Myra affinis was sequenced using next-generation sequencing to supplement the limited mitogenome information of *** 15349 bp-long mitogenome includes 13 protein-coding genes(PCGs),22 transfer RNAs(tRNAs),2 ribosomal RNAs(rRNAs),and a putative control *** overall base composition is 34.5%A,36.1%T,11.5%G,and 17.9%C,with a high AT bias(70.6%).All 13 PCGs start with the standard ATN codon and stop with the TAN codon or incomplete *** for tRNA-Ser,all other tRNAs have a typical cloverleaf-like secondary *** analyses based on the maximum likelihood and Bayesian inference methods are employed to generate identical phylogenetic topologies,thereby supporting the sister relationship between Leucosiidae and Matutidae for the first *** monophyly of Eubrachyura is well established,and its sister relationship with Raninoida is strongly *** results of this work will not only help achieve a better understanding of the characteristics of the *** mitogenome and the phylogenetic position of Leucosiidae,but also provide relevant information for further studies on the phylogeny of Brachyura.

关键词： leucosiid crab mitogenome phylogenetic analysis Brachyura

Comparative mitochondrial genome analysis of Sesarmidae and its phylogenetic implications

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Acta Oceanologica Sinica 2022年第8期41卷 62-73页

作者： Ying Zhang Lei Meng Liming Wei Bingjian liu liqin liu Zhenming Lü Yang Gao Li Gong National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization Zhejiang Ocean UniversityZhoushan 316022China Marine Science and Technology College Zhejiang Ocean UniversityZhoushan 316022China School of Fishery Zhejiang Ocean UniversityZhoushan 316022China

Here,we sequenced the complete mitogenome of Parasesarma eumolpe(Brachyura:Grapsoidea:Sesarmidae)for the first *** characteristics of this newly sequenced mitogenome were described and compared with other Sesarmidae *** 15646-bp mitogenome contains 13 protein-coding genes(PCGs),two ribosomal RNA genes(r RNAs),22 transfer RNA genes(t RNAs),and an A-T rich *** of the PCGs are initiated by the start codon ATN and terminated by the standard TAN codon or an incomplete *** pairwise Ka/Ks ratio analysis shows that all 13 PCGs are under purifying selection,whereas the ATP8 gene is an outlier,with pairwise comparison values ranging from neutral selection(0.000)to positive selection(1.039).The gene arrangement of *** compared with ancestral Decapoda shows the translocation of two t RNAs(t RNA-His and t RNA-Gln),which is identical to other Sesarmidae *** analyses show that all Sesarmidae species are placed into one group,and the polyphyly of Eriphioidea,Ocypodoidea,and Grapsoidea is well *** relationship between gaps in the QIM region and the phylogeny of Sesarmidae is *** is obvious that both the G5(the gap between Q and I)and G6(the gap between I and M)decrease progressively with the evolution *** results will help to better understand the genomic evolution within Sesarmidae and provide insights into the phylogeny of Brachyura.

关键词： sesarmid crab mitogenome gene rearrangement tandem duplication/random loss phylogenetic analysis