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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 heat.Interface stability and service performance are key points for the commercial applications of these materials.We utilized Mg_(4.3)Sb_(3)Ni as a barrier layer to improve the thermal stability of Mg 3 Sb 2-based devices.However,its intrinsic high resistivity contributed nega-tively to the desired performance of the device.In 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 resistivity.The 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

conversion efficiency Enhancement of Multi-crystalline Si Solar Cells by Using a Micro-structured Junction

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Chinese Physics Letters 2015年第11期32卷 161-165页

作者：郦莉虞栋吴仕良王伟刘文超吴小山张凤鸣 Collaborative Innovation Center of Advanced Microstructures Lab of Solid State Microstructures School of Physics Nanjing University Nanjing 210093 National Laboratory of Solid State Microstructures Center of Photovoltaic Engineering and School of Modern Engineering and Applied Sciences Nanjing University Nanjing 210093

A new approach for enhancing the conversion efficiency of solar cells is proposed. A surface with columnar structures is employed on the fabrication of multi-crystalline silicon solar cells, for increasing the collection probability of photon-generated minority carriers in the cells. For comparison, three types of surfaces （planar surface, surfaces with columns of 12μm in radius and columns of 9 μm in radius, respectively） are used. It is demonstrated that the cells with columnar structured surfaces have better spectral response and higher efficiencies than the cells with planar surface, while the cells with columns of 9 μm in radius show better spectral response than the cells with columns of 12 μm in radius. However, the cells with columns of 12 μm exhibit higher efficiencies than the cells with columns of 9 μm in radius for their difference in fill factors. Moreover, the effect of the columnar structured surface on the minority carrier collection efficiency is verified with wafers of different minority carrier lifetimes （0.5 μs and 1.0 μs）. This work may significantly consider its potential in the manufacturing of highefficiency solar cells at low cost by using low quality materials.

关键词： conversion efficiency

Breaking the efficiency limitations of dissipative Kerr solitons using nonlinear couplers

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 88-94页

作者： Ming Li Xiao-Xiao Xue Yan-Lei Zhang Xin-Biao Xu Chun-Hua Dong Guang-Can Guo Chang-Ling Zou CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Centerfor Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Department of Electronic Engineering Beijing National Research Center for Information Science and TechnologyTsinghua University Beijing 100084China

Dissipative Kerr solitons(DKS) have long been suffering from poor power conversion efficiency when driven by continuous-wave lasers. By deriving the critical coupling condition of a multimode nonlinear optics system in a generalized theoretical framework,two efficiency limitations of the conventional pump method of DKS are revealed: the effective coupling rate is too small and is also power-dependent. A general approach is provided to resolve this challenge by introducing two types of nonlinear couplers to couple the soliton cavity and CW input through nonlinear processes. The collective coupler opens multiple coupling channels and the self-adaptive coupler builds a power-independent effective external coupling rate to the DKS for approaching the generalized critical coupling condition, which promises near-unity power conversion efficiencies. For instance, a conversion efficiency exceeding 90% is predicted for aluminum nitride microrings with a nonlinear coupler utilizing second-harmonic generation. The mechanism applies to various nonlinear processes, including Raman and Brillouin scattering, and thus paves the way for micro-solitons toward practical applications.

关键词： Kerr frequency comb conversion efficiency nonlinear coupler

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

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：杨岑张永良 State Key Laboratory of Hydro-Science and Engineering Tsinghua University

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

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

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)

0.35%THz pulse conversion efficiency achieved by Ti:sapphire femtosecond laser filamentation in argon at 1 kHz repetition rate

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Opto-Electronic Advances 2022年第9期5卷 26-33页

作者： Zhiqiang Yu Nan Zhang Jianxin Wang Zijie Dai Cheng Gong Lie Lin Lanjun Guo Weiwei Liu Institute of Modern Optics Nankai UniversityTianjin 300350China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin 300350China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin 300350China

In this study,an optical setup for generating terahertz(THz)pulses through a two-color femtosecond laser filament was carefully designed to achieve a precise overlap of two-color laser pulses in space and time.β-barium borate(BBO),α-BBO,and a dual-wavelength plate were used to compensate the phase delay of the two-color lasers.Tilting ofα-BBO could further realize the precise spatial overlap of the two beams by counteracting the walk-off effect.The maximum out-put THz pulse energy reached 21μJ in argon gas when using a commercial Ti:sapphire laser with a pulse energy of 6 mJ at a 1 kHz repetition rate.The corresponding conversion efficiency exceeded 0.35%.

关键词： femtosecond laser filaments walk-off effect conversion efficiency

Three-Dimensional Study of the Effect of the Angle of Incidence of a Magnetic Field on the Electrical Power and conversion efficiency of a Polycrystalline Silicon Solar Cell under Multispectral Illumination

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Smart Grid and Renewable Energy 2022年第12期13卷 295-304页

作者： Idrissa Sourabié Vinci de Dieu Bokoyo Barandja Mahamadi Savadogo Ramatou Konaté Alain Doua Gnabahou Martial Zoungra Issa Zerbo Frédéric Ouattara Laboratoire de Chimie Analytique de Physique Spatiale et énergétique (L@CAPSE) Université Norbert ZONGO Koudougou Burkina Faso Laboratoire d’Energie Thermique Renouvelable (L.E.T.RE) Université Joseph KI ZERBO Ouagadougou Burkina Faso Department of Physics University of Bangui Bangui Central African Republic

A three-dimensional approach to the effect of magnetic field incidence angle on electrical power and conversion efficiency is performed on a front-illuminated polycrystalline silicon bifacial solar cell. A solution of the continuity equation allowed us to present the equations of photocurrent density, photovoltage and electric power. The influence of the angle of incidence of the magnetic field on the photocurrent density, the photovoltage and the electric power has been studied. The curves of electrical power versus dynamic junction velocity were used to extract the values of maximum electrical power and dynamic junction velocity and to calculate those of conversion efficiency. From this study, it is found that the conversion efficiency values increase with the angle of incidence of the magnetic field.

关键词： Angle of Incidence Magnetic Field Electric Power Bifacial Solar Cell conversion efficiency