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Power Absorption of A Two-Body Heaving Wave Energy Converter Considering Different Control and Power Take-off Systems

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China Ocean Engineering 2022年第1期36卷 15-27页

作者： DONG Xiao-chen GAO Zhen LI De-min HUANG Shu-ting shi hong-da Department of Ocean Engineering College of EngineeringOcean University of ChinaQingdao 266100China Department of Marine Technology and Centre for Autonomous Marine Operations and Systems(AMOS) Norwegian University of Science and Technology(NTNU)Trondheim 7491Norway Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China Qingdao Municipal Key Laboratory of Ocean Renewable Energy Ocean University of ChinaQingdao 266100China Institute of Marine Science and Technology Shandong UniversityQingdao 266237China

This study proposed a wave power system with two coaxial floating cylinders of different diameters and ***’s conceptual design has been adopted in the wave power *** this study,a basic analysis of the wave energy extraction by the relative motion between two floats is *** maximum power absorption was studied theoretically under regular wave conditions,and the effects of both linear and constant damping forces on the power take-off(PTO)were investigated.A set of dynamic equations describing the floats’displacement under regular waves and different PTOs are established.A time-domain numerical model is developed,considering the PTO parameter and viscous damping,and the optimal PTO damping and output power are *** the analysis of estimating the maximum power absorption,a new estimation method called Power Capture Function(PCF)is proposed and constructed,which can be used to predict the power capture under both linear and constant PTO *** on this,energy extraction is analyzed and ***,the performance characteristics of the two-body power system are concluded.

关键词： two-body heaving wave energy converter power capture function power take-off

Hydrodynamic Performance and Power Absorption of A Coaxial DoubleBuoy Wave Energy Converter

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China Ocean Engineering 2023年第3期37卷 378-392页

作者： LI De-min DONG Xiao-chen LI Yan-ni HUANG He-ao shi hong-da College of Engineering Ocean University of ChinaQingdao 266400China Shandong Provincial Key Laboratory of Ocean Engineering Qingdao 266100China Qingdao Municipal Key Laboratory of Ocean Renewable Energy Ocean University of ChinaQingdao 266100China

As an important wave energy converter(WEC),the double-buoy device has advantages of wider energy absorption band and deeper water adaptability,which attract an increasing number of attentions from *** paper makes an in-depth study on double-buoy WEC,by means of the combination of model experiment and numerical *** Response Amplitude Operator(RAO)and energy capture of the double-buoy under constant power take-off(PTO)damping are investigated in the model test,while the average power output and capture width ratio(CWR)are calculated by the numerical simulation to analyze the influence of the wave condition,PTO,and the geometry parameters of the *** AQWA-Fortran united simulation sy stem,including the secondary developme nt of AQWA software coupled with the flowchart of the Fortran code,models a new dynamic *** viscous damping and hydraulic friction from WEC system are measured from the experimental results,and these values are added to the equation of *** a result,the energy loss is contained in the final numerical model the by united simulation *** the developed numerical model,the optimal period of energy capture is *** power capture reaches the maximum value under the outer buoy's natural *** paper gives the peak value of the energy capture under the linear PTO damping force,and calculates the optimal mass ratio of the device.

关键词： coaxial double-buoy wave energy converter physical model experiment numerical simulation hydrodynamic performance

Understanding the Thermal Impedance of Silicone Rubber/Hexagonal Boron Nitride Composites as Thermal Interface Materials

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Chinese Journal of Polymer Science 2024年第3期42卷 352-363,I0008页

作者： Yuan Ji shi-da Han hong Wu Shao-Yun Guo Feng-Shun Zhang Jian-Hui Qiu The State Key Laboratory of Polymer Materials Engineering Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyPolymer Research InstituteSichuan UniversityChengdu 610065China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Department of Mechanical Engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.

关键词： Thermal interface materials Hexagonal boron nitride Thermal impedance Surfaces

Capture Performance of A Multi-Freedom Wave Energy Converter with Different Power Take-off Systems

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China Ocean Engineering 2019年第3期33卷 288-296页

作者： HUANG Shu-ting shi hong-da DONG Xiao-chen College of Engineering Ocean University of China Qingdao 266100 China Shandong Provincial Key Laboratory of Ocean Engineering Qingdao 266100 China

Among the wave energy converters (WECs), oscillating buoy is a promising type for wave energy development in offshore area. Conventional single-freedom oscillating buoy WECs with linear power take-off (PTO) system are less efficient under off-resonance conditions and have a narrow power capture bandwidth. Thus, a multi-freedom WEC with a nonlinear PTO system is proposed. This study examines a multi-freedom WEC with 3 degrees of freedom: surge, heave and pitch. Three different PTO systems (velocity-square, snap through, and constant PTO systems) and a traditional linear PTO system are applied to the WEC. A time-domain model is established using linear potential theory and Cummins equation. The kinematic equation is numerically calculated with the fourth-order Runge–Kutta method. The optimal average output power of the PTO systems in all degrees of freedom are obtained and compared. Other parameters of snap through PTO are also discussed in detail. Results show that according to the power capture performance, the order of the PTO systems from the best to worst is snap through PTO, constant PTO, linear PTO and velocity-square PTO. The resonant frequency of the WEC can be adjusted to the incident wave frequency by choosing specific parameters of the snap through PTO. Adding more DOFs can make the WEC get a better power performance in more wave frequencies. Both the above two methods can raise the WEC’s power capture performance significantly.

关键词： oscillating buoy wave energy converter nonlinear power take-off multi-freedom power capture

Magnetic Fields Reduce Apoptosis by Suppressing Phase Separation of Tau-441

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Research 2024年第1期2023卷 181-197页

作者： Wen-Juan Lin Wen-Pu shi Wan-Yi Ge Liang-Liang Chen Wei-hong Guo Peng Shang da-Chuan Yin Key Laboratory for Space Bioscience and Biotechnology School of Life SciencesNorthwestern Polytechnical University127 Youyixi RoadXi'an 710072ShaanxiPR China

The biological effects of magnetic fields(MFs)have been a controversial ***,in recent years,there has been increasing evidence that MFs do affect biological ***,the physical mechanism remains ***,we show that MFs(16 T)reduce apoptosis in cell lines by inhibiting liquid–liquid phase separation(LLPS)of Tau-441,suggesting that the MF effect on LLPS may be one of the mechanisms for understanding the“mysterious”magnetobiological *** LLPS of Tau-441 occurred in the cytoplasm after induction with *** phase-separated droplets of Tau-441 recruited hexokinase(HK),resulting in a decrease in the amount of free HK in the *** cells,HK and Bax compete to bind to the voltage-dependent anion channel(VdaC I)on the mitochondrial membrane.A decrease in the number of free HK molecules increased the chance of Bax binding to VdaC I,leading to increased Bax-mediated *** the presence of a static MF,LLPS was marked inhibited and HK recruitment was reduced,resulting in an increased probability of HK binding to VdaC I and a decreased probability of Bax binding to VdaC I,thus reducing Bax-mediated *** findings revealed a new physical mechanism for understanding magnetobiological effects from the perspective of *** addition,these results show the potential applications of physical environments,such as MFs in this study,in the treatment of LLPS-related diseases.

关键词： inhibited Apoptosis finding

Theoretical and Experimental Study of A Coaxial Double-Buoy Wave Energy Converter

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China Ocean Engineering 2021年第3期35卷 454-464页

作者： LI De-min DONG Xiao-chen shi hong-da LI Yan-ni Department of Ocean Engineering College of EngineeringOcean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China Qingdao Municipal Key Laboratory of Ocean Renewable Energy Ocean University of ChinaQingdao 266100China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266200China

The double-body heave wave energy converter(WEC)is one of the most conducive devices to absorb the wave energy from relative motion while the law of which is not well *** paper makes an in-depth study on this wave energy converter,by means of the combination of theoretical analysis and physical model *** hydrodynamic characteristics and energy capture of the double-buoy under constant and linear Power Take-Off(PTO)damping are *** of absolute mass and mass ratio are discussed in the theoretical *** displacement amplitude and average power output are tested in the experiment to analyze the effect of the wave period and outer buoy’s mass,while the capture width ratio(CWR)is also *** show that the wave period and mass of the buoys have a significant effect on the *** forms of PTO damping have no influence on the optimal wave period and mass ratio of this *** is recommended to select the double-buoy converter with a mass ratio of 0.80 and to place it in an area with the frequent wave period close to the natural period of the outer buoy to achieve the optimal energy capture.

关键词： coaxial double-buoy wave energy converter hydrodynamic characteristics model test power take-off

Stability of the Phase Separation State for Compressible Navier-Stokes/Allen-Cahn System

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 45-74页

作者： Ya-zhou Chen Hakho hong Xiao-ding shi Department of Mathematics College of Mathematics and PhysicsBeijing University of Chemical TechnologyBeijing100029China Institute of Mathematics State Academy of SciencesPyongyangKorea

This paper is concerned with the large time behavior of the Cauchy problem for Navier-Stokes/AllenCahn system describing the interface motion of immiscible two-phase flow in 3-D. The existence and uniqueness of global solutions and the stability of the phase separation state are proved under the small initial perturbations. Moreover, the optimal time decay rates are obtained for higher-order spatial derivatives of density,velocity and phase. Our results imply that if the immiscible two-phase flow is initially located near the phase separation state, then under small perturbation conditions, the solution exists globally and decays algebraically to the complete separation state of the two-phase flow, that is, there will be no interface fracture, vacuum, shock wave, mass concentration at any time, and the interface thickness tends to zero as the time t → +∞.

关键词： Navier-Stokes/Allen-Cahn system existence uniqueness large time behavior decay rate

Research on intelligent search-and-secure technology in accelerator hazardous areas based on machine vision

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Nuclear Science and Techniques 2024年第4期35卷 96-107页

作者： Ying-Lin Ma Yao Wang hong-Mei shi Hui-Jie Zhang School of Traffic and Transportation Beijing Jiaotong UniversityBeijing 100044China School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

Prompt radiation emitted during accelerator operation poses a significant health risk,necessitating a thorough search and securing of hazardous areas prior to ***,manual sweep methods are ***,the limitations of manual sweeps have become increasingly evident with the implementation of large-scale *** leveraging advancements in machine vision technology,the automatic identification of stranded personnel in controlled areas through camera imagery presents a viable solution for efficient search and *** the criticality of personal safety for stranded individuals,search and security processes must be sufficiently *** ensure comprehensive coverage,180°camera groups were strategically positioned on both sides of the accelerator tunnel to eliminate blind spots within the monitoring *** YOLOV8 network model was modified to enable the detection of small targets,such as hands and feet,as well as larger targets formed by individuals near the ***,the system incorporates a pedestrian recognition model that detects human body parts,and an information fusion strategy is used to integrate the detected head,hands,and feet with the identified pedestrians as a cohesive *** strategy enhanced the capability of the model to identify pedestrians obstructed by equipment,resulting in a notable improvement in the recall ***,recall rates of 0.915 and 0.82were obtained for datasets 1 and 2,*** there was a slight decrease in accuracy,it aligned with the intended purpose of the search-and-secure software *** tests conducted within an accelerator tunnel demonstrated the effectiveness of this approach in achieving reliable recognition outcomes.

关键词： Search and secure Machine vision Camera Human body parts recognition Particle accelerator Hazardous area

Controlling hydrogenation of C=C and C=O bonds in cinnamaldehyde using Pt_(1)/Ni and Pt_(1)/Co single-atom alloy catalysts

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Rare Metals 2024年第6期43卷 2859-2868页

作者： Huan-shi Lan Yi-da Yang Qing-Di Sun Hao Zhang Ying Zhang Qian He Ran Chen Guo-Yi Bai Xiao-Hui He hong-Bing Ji School of Chemistry and Chemical Engineering Guangxi UniversityNanning 530004China Key Laboratory of Bioinorganicand Synthetic Chemistry of Ministry of Education Fine Chemical Industry Research InstituteSchool of ChemistryIGCMESun Yat-sen UniversityGuangzhou510275China UBFC CNRSENSMMFEMTO-ST Institute25030 Besancon CEDEXFrance College of Chemistry and Materials Science Hebei UniversityBaoding 071002China State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology Institute of Green Petroleum Processing and Light Hydrocarbon ConversionCollege of Chemical EngineeringZhejiang University of TechnologyHangzhou 310014China

Selective hydrogenation of C=C and C=O bonds in cinnamaldehyde(CAL)to produce desired products is a challenging task due to the complex conjugate system of the two unsaturated functional *** this study,a simple ball milling method is presented for synthesizing Pt-based single-atom alloy catalysts(SAAs)that can function as a control switch for the selective hydrogenation of CAL into highly valuable products.

关键词： alloy hydrogenation conjugate