中国科学院机构知识库网格系统: 检索

A High-Efficiency System for Long-Term Salinity-Gradient Energy Harvesting and Simultaneous Solar Steam Generation 期刊论文 OAI收割
ADVANCED ENERGY MATERIALS, 2024, 页码: 10
作者: Long, Jun; Yin, Jun; Yang, Fuhua; Zhou, Guangmin; Cheng, Hui-Ming

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收藏 | 浏览/下载：1/0 | 提交时间：2025/04/27

anion-exchange membrane electrochemical potentials high-efficiency device salinity concentration gradient solar steam generation

Optimizing Training Efficiency and Cost of Hierarchical Federated Learning in Heterogeneous Mobile-Edge Cloud Computing 期刊论文 OAI收割
IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS, 2023, 卷号: 42, 期号: 5, 页码: 1518-1531
作者: Cui, Yangguang; Cao, Kun; Zhou, Junlong; Wei, Tongquan

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Training Servers Cloud computing Delays Costs Computational modeling Prototypes Device frequency determination federated learning (FL) high efficiency low cost mobile-edge cloud computing (MECC) user selection

Epitaxially-Stacked High Efficiency Laser Diodes Near 905 nm 期刊论文 OAI收割
IEEE PHOTONICS JOURNAL, 2022, 卷号: 14, 期号: 6
作者: Zhao, Yuliang; Yang, Guowen; Zhao, Yongming; Tang, Song; Lan, Yu

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收藏 | 浏览/下载：71/0 | 提交时间：2022/11/08

Epitaxial growth Resistance Doping Optical losses Optical device fabrication Stacking Optical refraction Epitaxial stacking high efficiency laser diode low optical loss n-doping concentration power scaling specific resistance tunnel junction

Structural amelioration of 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
作者: Liu Y.; Liu Y.; Wang L.; Wang L.; Wang L.

收藏 | 浏览/下载：52/0 | 提交时间：2013/03/25

920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) has an important application in laser display. We constructed and optimized a 920 nm OPS-VECSEL with active region of In0.09Ga0.91As quantum well (QW) system pumped by 808 nm laser diode module. By the finite element method self-consistent solutions of the semiconductor electronic and optical equations are realized to calculate the characteristics parameters of OPS-VECSEL. The performances of device especially the mode the threshold and the optical-optical translation efficiency were analyzed by dealing with different number of QWs (1 2 and 3) in one period QW depth barrier width the component and dimension of the non-absorption layer. We chose an improved structure of them. On this basis we ameliorated the number of QW periods and the simulation showed that in order to obtain high performance device the choice of the number of QW periods must be cautious. (2013) Trans Tech Publications Switzerland.

Theoretical analysis of emission characteristics of second-order distributed feedback semiconductor lasers (EI CONFERENCE) 会议论文 OAI收割
Semiconductor Lasers and Applications IV, October 18, 2010 - October 19, 2010, Beijing, China
作者: Liu Y.; Liu Y.; Qin L.; Liu Y.; Wang L.

收藏 | 浏览/下载：51/0 | 提交时间：2013/03/25

Based on the modified coupled-wave theory the emission characteristics including threshold gain photon density distribution in the cavity and external differential quantum efficiency for second-order DFB lasers are investigated. Numerical simulation results show that for given device structure with wavelength of 1.55 m the feedback coupling coefficient and the surface radiation coupling coefficient of the second-order grating have great influence on the emission characteristics of the device. By choosing different duty cycles of the grating we can change the two coupling coefficients which affect the emission characteristics. For an overall consideration an optimal duty cycle of 0.43 is chosen. The optimized results show that the device works without degeneracy modes and spatial burning hole. Besides the side-mode suppress ratio (SMSR) and external differential quantum efficiency reach as high as 42 dB and 47% respectively. 2010 SPIE.

Auto-detection system of photoelectric encoder based on DSP (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Industrial and Information Systems, IIS 2010, July 10, 2010 - July 11, 2010, Dalian, China
作者: Wan Q.-H.; Qi L.-L.; Liang L.-H.; Lu X.-R.; Du Y.-C.

收藏 | 浏览/下载：44/0 | 提交时间：2013/03/25

To improve the automatic detection efficiency of photoelectric encoder an auto-detection system of photoelectric encoder is designed using DSP (TMS320F2812) as the core device. A 21-bit high accuracy photoelectric encoder is used as the angle standard. It is connected to the detected photoelectric encoder coaxially. They will rotate synchronously under the driving of electric motor. Data acquisition and processing system collects the angular data of the two photoelectric encoders at the same angular position and calculates the angular error of detected photoelectric encoder. Then the data is put into computer. The computer will display the data error. The result of experiment shows that the system could detect encoder whose bit-number below 19 the detecting person could be reduced to one and the detecting speed could be increased to 8-10 times. 2010 IEEE.

Electroluminescence of poly(N-vinylcarbazole) films: fluorescence, phosphorescence and electromers 期刊论文 OAI收割
physical chemistry chemical physics, 2010, 卷号: 12, 期号: 47, 页码: 15410-15413
Ye TL; Chen JS; Ma DG

收藏 | 浏览/下载：38/0 | 提交时间：2012/04/25

LIGHT-EMITTING-DIODES HIGH-EFFICIENCY POLYMER MORPHOLOGY DEVICE PERFORMANCE IRIDIUM COMPLEXES THIN-FILM EMISSION LUMINESCENCE COPOLYMER

Temperature characteristics of high power vertical cavity surface emitting lasers (EI CONFERENCE) 会议论文 OAI收割
Semiconductor Lasers and Applications III, November 12, 2007 - November 13, 2007, Beijing, China
作者: Qin L.

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By using oxidation confinement technology high power vertical-cavity surface-emitting lasers are fabricated in experiment. The electrical and optical performance characteristics such as threshold current efficiency emission wavelength and output power are measured under continuous wave (CW) condition at room temperature. The maximum output power is up to watt regime at wavelength of about 980nm. The temperature characteristics of the device are investigated experimentally in detail. The variation in lasing threshold current with temperature is studied. The characteristic temperature T0 of the device is derived and the value is about 211K. Such a high characteristic temperature T0 of threshold current can lead to good temperature sensitivity of the device. At the same time the lasing spectrum characteristics with temperature are also measured. The wavelength shift with temperature is just about 0.06nm/K. From the measured results it is shown that the device can still operate at high temperature condition.

High power VCSEL device with periodic gain active region (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China
作者: Zhang Y.; Liu Y.; Liu Y.; Liu Y.; Qin L.

收藏 | 浏览/下载：54/0 | 提交时间：2013/03/25

High power vertical cavity surface emitting lasers with large aperture have been fabricated through improving passivation lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structure a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the cavity to enhance the coupling between the optical field and the gain region. Large aperture and bottom-emitting configuration was used to improve the beam quality and the heat dissipation. A maximum output power of 1.4W was demonstrated at CW operation for a 400m-diameter device. The lasing wavelength shifted to 995.5nm with a FWHM of 2nm at a current of 4.8A due to the internal heating and the absence of active water cooling. A ring-shape farfield pattern was induced by the non-homogeneous lateral current distribution in large diameter device. The light intensity at the center of the ring increased with increasing current. A symmetric round light spot at the center and single transverse mode operation with a divergence angle of 16 were observed with current beyond 4.8A.

A new driving method for LCoS with frame buffer pixels (EI CONFERENCE) 会议论文 OAI收割
ICO20: Display Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
Song Y.; Ling Z.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

A new driving method for LCoS microdisplays with frame buffer pixels was developed here. The power dissipation of the LCoS microdisplays with frame buffer pixels is higher than that of the LCoS with DRAM-like pixels due to the twice samplings in LCoS with frame buffer pixels. In this paper an adiabatic charging method was used to the second sampling of the frame buffer pixels in order to reduce the power dissipated in the transistors. The power dissipation of the second sampling was calculated when the power sources of the step the ramp and the stair-step are used respectively. The conventional design adopted the step and contributed to high power and so result in more heat to deteriorate the device performance. The power dissipated in the transistors is almost zero if the ideal ramp source is used. The ramp can be the stair-step whose steps are infinity. The stair-step substitutes for the ramp due to easily generation and higher energy efficiency than the step. It can decrease the power dissipation of the LCoS panel and contributes to the heat reduction caused by power dissipation which can increase the microdisplay devices reliability. This method was developed based on the frame buffer pixel circuits which we proposed previously and can be applied to the others.