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Improvement of the conversion efficiency of Mg_(3)Sb_(2)thermoelectric devices through optimizing the resistivity of the MgSbNi barrier layer

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Journal of Materials Science & Technology 2024年第1期168卷 208-214页

作者： Huimin Zhang Yachao Wang Zuhair A.Munir Yongzhong Zhang Wenhao Fan Shaoping Chen College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China Capital Aerospace Machinery Company Beijing100076China Department of Material Science and Engineering University of CaliforniaDavisCalifornia95616United States of America College of Physics and Optoelectronics Taiyuan University of TechnologyTaiyuan030024China Instrumental Analysis Center of Taiyuan University of Technology Taiyuan030024China

Mg_(3)Sb_(2)-based thermoelectric materials have been the focus of widespread investigations as promising candidates for the harvesting of waste *** stability and service performance are key points for the commercial applications of these *** utilized Mg_(4.3)Sb_(3)Ni as a barrier layer to improve the thermal stability of Mg 3 Sb 2-based ***,its intrinsic high resistivity contributed nega-tively to the desired performance of the *** this work,we investigated two other Mg-Sb-Ni ternary phases,MgSbNi and MgSbNi_(2),as new barrier layer materials to connect with Mg_(3.2)Sb_(2)Y_(0.05).The results show that the efficiency of the Mg_(1.2)SbNi/Mg_(3.2)Sb_(2)Y_(0.05)/Mg_(1.2)SbNi joint is increased by 33%relative to the higher Mg-content barriers due to lower *** system exhibited good interfacial compatibility and showed little change with aging at 673 K for 20 days.

关键词： Mg_(3)Sb_(2) Mg_(1.2)SbNi Barrier layer conversion efficiency

Dynamic Properties and Energy conversion efficiency of A Floating Multi-Body Wave Energy Converter

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China Ocean Engineering 2018年第3期32卷 347-357页

作者： YANG Shao-hui WANG Yong-qing HE Hong-zhou ZHANG Jun CHEN Hu College of Mechanical and Energy Engineering Jimei UniversityXiamen 361021China Key Laboratory of Energy Cleaning Utilization and Development of Fujian Province Xiamen 361021China Key Laboratory of Ocean Renewable Energy Equipment Fujian Province UniversityXiamen 361021China

The present study proposed a floating multi-body wave energy converter composed of a floating central platform,multiple oscillating bodies and multiple actuating arms. The relative motions between the oscillating bodies and the floating central platform capture multi-point wave energy simultaneously. The converter was simplified as a forced vibration system with three degrees of freedom, namely two heave motions and one rotational motion. The expressions of the amplitude-frequency response and the wave energy capture width were deduced from the motion equations of the converter. Based on the built mathematical model, the effects of the PTO damping coefficient, the PTO elastic coefficient, the connection length between the oscillating body and central platform, and the total number of oscillating bodies on the performance of the wave energy converter were investigated. Numerical results indicate that the dynamical properties and the energy conversion efficiency are related not only to the incident wave circle frequency but also to the converter’s physical parameters and interior PTO coefficients. By adjusting the connection length, higher wave energy absorption efficiencies can be obtained. More oscillating bodies installed result in more stable floating central platform and higher wave energy conversion efficiency.

关键词： Wave energy converter multi-point absorption conversion efficiency vibration properties

Thermally confined shell coating amplifies the photoacoustic conversion efficiency of nanoprobes

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Nano Research 2016年第12期9卷 3644-3655页

作者： Yujiao Shi Huan Qin Sihua Yang Da Xing Ministry of Education Key Laboratory of Laser Life Science and Institute of Laser Life Science College of Biophotonics South China Normal University Guangzhou 510631 China

Efficient probes/contrast agents are highly desirable for good-performance photoacoustic （PA） imaging, where the PA signal amplitude of a probe is dominated by both its optical absorption and the conversion efficiency from absorbed laser energy to acoustic waves. Nanoprobes have a unique micro- mechanism of PA energy conversion due to the size effect, which, however, has not been quantitatively demonstrated and effectively utilized. Here, we present quantitative simulations of the PA signal production process for plasmon- mediated nanoprobes based on the finite element analysis method, which were performed to provide a deep understanding of their PA conversion micromechanism. Moreover, we propose a method to amplify the PA conversion efficiency of nanoprobes through the use of thermally confined shell coating, which allows the active control of the conversion efficiency beyond that of conventional probes. Additionally, we deduced the dependence of the conversion efficiency on the shell properties. Gold-nanoparticles/polydimethylsiloxane nanocomposites were experimentally synthesized in the form of gel and microfilms to verify our idea and the simulation results agreed with the experiments. Our work paves the way for the rational design and optimization of nanoprobes with improved conversion efficiency.

关键词： photoacousticnanoprobes micromechanism conversion efficiency shell coating

New insight into photoacoustic conversion efficiency by plasmon-mediated nanocavitation： Implications for precision theranostics

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Nano Research 2017年第8期10卷 2800-2809页

作者： Yujiao Shi Sihua Yang Da Xing Ministry of Education Key Laboratory of Laser Life Science and Institute of Laser Life Science College of Biophotonics South China Normal University Guangzhou 510631 China

The probe-assisted integration of imaging and therapy into a single modality offers significant advantages in bio-applications. As a newly developed photoacoustic （PA） mechanism, plasmon-mediated nanocavitation, whereby photons are effectively converted into PA shockwaves, has excellent advantages for image-guided therapy. In this study, by simulating the laser absorption, temperature field, and nanobubble dynamics using both finite-element analysis and computational fluid dynamics, we quantified the cavitation-induced PA conversion efficiency of a water-immersed gold nanosphere, revealing new insights. Interestingly, sequential multi-bubble emission accompanied by high PA signal production occur under a single high-dose pulse of laser irradiation, enabling a cavitation-induced PA conversion efficiency up to 2%, which is -50 times higher than that due to thermal expansion. The cavitation-induced PA signal has unique frequency characteristics, which may be useful for a new approach for in vivo nanoparticle tracking. Our work offers theoretical guidance for accurate diagnosis and controllable therapy based on plasmon-mediated nanocavitation.

关键词： photoacoustic imaging conversion efficiency nanocavitation theranostics

Numerical study of hydrodynamic behavior and conversion efficiency of a two-buoy wave energy converter

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Journal of Hydrodynamics 2018年第2期30卷 235-248页

作者： Cen Yang Yong-liang Zhang State Key Laboratory of Hydro-Science and Engineering Tsinghua University Beijing 100084 China

In this paper we propose a two-buoy wave energy converter composed of a heaving semi-submerged cylindrical buoy, a fixed submerged cylindrical buoy and a power take-off（PTO） system, and investigate the effect of the fixed submerged buoy on the hydrodynamics of the heaving semi-submerged buoy based on the three-dimensional potential theory. And the dynamic response of the semi-submerged buoy and the wave energy conversion efficiency of the converter are analyzed. The difference of the hydrodynamics and the wave energy conversion efficiency of a semi-submerged buoy converter with and without a fixed submerged buoy is discussed. It is revealed that the influence of the fixed submerged buoy on the exciting wave force, the added mass, the radiation damping coefficient and the wave energy conversion efficiency can be significant with a considerable variation, depending on the vertical distance between the heaving semi-submerged buoy and the fixed submerged buoy, the diameter ratio of the fixed submerged buoy to the heaving semi-submerged buoy and the water depth.

关键词： Wave energy converter two-buoy hydrodynamics conversion efficiency fluid-structure interaction power take-off

Electroreduction of air‐level CO_(2) with high conversion efficiency

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Chinese Journal of Catalysis 2022年第7期43卷 1703-1709页

作者： Yangshen Chen Miao Kan Shuai Yan Junbo Zhang Kunhao Liu Yaqin Yan Anxiang Guan Ximeng Lv Linping Qian Gengfeng Zheng Laboratory of Advanced Materials Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsFaculty of Chemistry and Materials ScienceFudan UniversityShanghai 200438China

The electrochemical conversion of carbon dioxide(CO_(2))has been attracting increasingly research interest in the past decade,with the ultimate goal of utilizing electricity from renewable energy to realize carbon neutrality,as well as economic and energy ***,the capture and concentrating of CO_(2) cost a substantial portion of energy,while almost all the reported researches showed CO_(2) electroreduction under high concentrations of(typically pure)CO_(2) reactants,and only very few recent studies have investigated the capability of applying low CO_(2) concentrations(such as~10%in flue gases).In this work,we first demonstrated the electroreduction of 0.03%CO_(2)(in helium)in a homemade gas‐phase electrochemical electrolyzer,using a low‐cost copper(Cu)or nanoscale copper(nano‐Cu)*** with steam,the gas‐phase CO_(2) was directly delivered onto the gas‐solid interface with the Cu catalyst and reduced to CO,without the need/constraint of being adsorbed by aqueous solution or alkaline *** tuning the catalyst and experi‐mental parameters,the conversion efficiency of CO_(2) reached as high as~95%.Furthermore,we demonstrated the direct electroreduction of 0.04%CO_(2) from real air sample with an optimized conversion efficiency of~79%,suggesting a promising perspective of the electroreduction ap‐proach toward direct CO_(2) conversion.

关键词： CO_(2)conversion Electrocatalysis Low concentration CO_(2) Flow rate conversion efficiency

A thermoelectric generator and water-cooling assisted high conversion efficiency polycrystalline silicon photovoltaic system

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Frontiers in Energy 2021年第2期15卷 358-366页

作者： Zekun LIU Shuang YUAN Yi YUAN Guojian LI Qiang WANG Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China Key Laboratory of Electromagnetic Processing of Materials of the Ministry of Education Northeastern UniversityShenyang 110819China

Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic (PV) cell and improve the utilization efficiency of solar energy, a hybrid system composed of the PV cell, a thermoelectric generator (TEG), and a water-cooled plate (WCP) was manufactured. The WCP cannot only cool the PV cell, but also effectively generate additional electric energy with the TEG using the waste heat of the PV cell. The changes in the efficiency and power density of the hybrid system were obtained by real time monitoring. The thermal and electrical tests were performed at different irradiations and the same experiment temperature of 22°C. At a light intensity of 1000 W/m2, the steady-state temperature of the PV cell decreases from 86.8°C to 54.1°C, and the overall efficiency increases from 15.6% to 21.1%. At a light intensity of 800 W/m2, the steady-state temperature of the PV cell decreases from 70°C to 45.8°C, and the overall efficiency increases from 9.28% to 12.59%. At a light intensity of 400 W/m2, the steady-state temperature of the PV cell decreases from 38.5°C to 31.5°C, and the overall efficiency is approximately 3.8%, basically remain unchanged.

关键词： photovoltaic(PV) thermoelectric generator conversion efficiency hybrid energy systems water-cooled plate(WCP)

Laser-induced rotary micromotor with high energy conversion efficiency

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Photonics Research 2020年第4期8卷 534-538页

作者： YU ZHANG SIYU LIN ZHIHAI LIU YAXUN ZHANG JIANZHONG ZHANG JUN YANG LIBO YUAN Key Laboratory of In-fiber Integrated Optics Ministry of EducationHarbin Engineering UniversityHarbin 150001China National Demonstration Center for Experimental Physics Education Harbin Engineering UniversityHarbin 150001China Photonics Research Center Guilin University of Electronics TechnologyGuilin 541004China

Light is a precious resource that nature has given to human *** green,recyclable light energy into the mechanical energy of a micromotor is undoubtedly an exciting ***,the performance of current light-induced micromotor devices is unsatisfactory,as the light-to-work conversion efficiency is only10-15–*** this paper,we propose and demonstrate a laser-induced rotary micromotor operated byΔα-type photopheresis in pure liquid glycerol,whose energy conversion ratio reaches as high as 10-9,which is 3–6 orders of magnitude higher than that of previous light-induced micromotor *** addition,we operate the micromotor neither with a light field carrying angular momentum nor with a rotor with a special rotating symmetrical *** just employ an annular-core fiber to configure a conical-shaped light field and select a piece of graphite sheet(with an irregular shape)as the ***Δα-type photophoretic force introduced by the conicalshaped light field drives the rotation of the graphite *** achieve a rotation rate up to 818.2 r/min,which can be controlled by tuning the incident laser *** optical rotary micromotor is available for twisting macromolecules or generating vortex and shear force in a medium at the nanoscale.

关键词： Laser-induced rotary micromotorhigh energy conversion efficiency

A Model for Extreme Ultraviolet Radiation conversion efficiency From Laser Produced Mass-Limited Tin-Based Droplet Target Plasmas

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Communications in Theoretical Physics 2012年第4期57卷 695-700页

作者：吴涛王新兵余仕成熊伦 Wuhan National Laboratory for Optoelectronics School of Optoelectronic Science and EngineeringHuazhong University of Science and Technology School of Science Wuhan Institute of Technology

Simple arguments are used to construct a model to explain the extreme ultraviolet radiation conversion efficiency(EUV-CE) of a tin-based droplet target laser produced plasmas by calculating the laser absorption efficiency,radiation efficiency,and spectral *** dependence of drive laser pulse duration and laser intensity on EUV-CE is *** results show that at some appropriate laser intensity,where the sum energy of the thermal conduction,out-off band radiation and plasma plume kinetic losses is at a minimum,the EUV-CE should reach a *** EUV-CE predicted by the present simple model is also compared with the available experimental and simulation data and a fair agreement between them is found.

关键词： conversion efficiency laser produced plasma extreme ultraviolet lithography