A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate,in which the beams travel in a geometric path similar to the outline of...A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate,in which the beams travel in a geometric path similar to the outline of a sickle.The maximum reflectivity is up to 168%.Faster response times are measured and are also simulated as a function of incident beam power ratio.Four available input geometries are found.The phase conjugation signals exist wide range of angular and positional alignment.No apparent cross talk is observed.The faster build-up process of phase conjugation beams is tentatively explained.展开更多
A mutually pumped phase conjugator with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate is reported,in which both incoherent beams are incident upon the negative c face and th...A mutually pumped phase conjugator with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate is reported,in which both incoherent beams are incident upon the negative c face and they travel in geometric paths similar to the outline of two arches.The maximum reflectivity attains 21%.The tolerance of the output to both incident angles and positions is assessed.No apparent cross talk is observed.A cross-readout mechanism is also used to explain phase-conjugate reflectivity production.It is verified that the configuration can be realized easily for a crystal with two longer a sides.展开更多
An extended crowding genetic algorithm (ECGA) is introduced for solvingoptimal pump configuration problem, which was presented by T. Westerlund in 1994. This problem hasbeen found to be non-convex, and the objective f...An extended crowding genetic algorithm (ECGA) is introduced for solvingoptimal pump configuration problem, which was presented by T. Westerlund in 1994. This problem hasbeen found to be non-convex, and the objective function contained several local optima and globaloptimality could not be ensured by all the traditional MINLP optimization method. The concepts ofspecies conserving and composite encoding are introduced to crowding genetic algorithm (CGA) formaintain the diversity of population more effectively and coping with the continuous and/or discretevariables in MINLP problem. The solution of three-levels pump configuration got from DICOPT++software (OA algorithm) is also given. By comparing with the solutions obtained from DICOPT++, ECPmethod, and MIN-MIN method, the ECGA algorithm proved to be very effective in finding the globaloptimal solution of multi-levels pump configuration via using the problem-specific information.展开更多
Six configurations are proposed in this paper to explore the gain and noise figure (NF) variations under the pumping power effect. I propose a new investigation of gain and NF at different EDFA configurations. Configu...Six configurations are proposed in this paper to explore the gain and noise figure (NF) variations under the pumping power effect. I propose a new investigation of gain and NF at different EDFA configurations. Configurations such as SPSS, DPSS, DPSSF, TPDS, TPDSF, and QPDSF are designed, investigated and compared. A continuous progress of gain values is observed from SPSS to QPDSF, and a change of NF values related to configurations is recorded. The NF variations show different behaviors at different configurations. High gain of 59.49 dB and low NF value of 4.22 dB are recorded for the QPDSF configuration and low gain and low NF are recorded for the SPSS configuration.展开更多
We experimentally demonstrate a high power nanosecond pulsed terahertz(THz)-wave parametric oscillator(TPO)by using a wide pump beam.A surface emitted cavity configuration is employed to reduce the THz absorption in M...We experimentally demonstrate a high power nanosecond pulsed terahertz(THz)-wave parametric oscillator(TPO)by using a wide pump beam.A surface emitted cavity configuration is employed to reduce the THz absorption in MgO:LiNbO_(3) crystal.The THz wave can be tuned from 1 THz to 3 THz.A maximum THz output energy of 438 nJ/pulse is achieved at 1.56 Hz using a 4.5-mm-diameter pump beam with a pulse energy of 226 mJ pump energy with the repetition of 10 Hz,corresponding to the energy conversion efficiency of 1.94×10^(-6).展开更多
面向“30·60”双碳目标,矿区能源利用方式的绿色、经济、高效转型成为我国能源革命的迫切需求。西部矿区拥有丰富的可再生能源资源禀赋,但仍面临着可再生能源就地消纳困难,电力设备投资成本高、利用率低以及外送输电通道有限的困...面向“30·60”双碳目标,矿区能源利用方式的绿色、经济、高效转型成为我国能源革命的迫切需求。西部矿区拥有丰富的可再生能源资源禀赋,但仍面临着可再生能源就地消纳困难,电力设备投资成本高、利用率低以及外送输电通道有限的困难。为提升矿区用能清洁化程度,提升矿区能源供给的稳定性与可靠性,增强矿区对外部电网的支撑能力,提出全清洁能源下的高品质矿区能源系统(High-quality Coal Mine Energy System,HCMES)及其配置优化方法。首先,考虑西部矿山综合能源系统的负荷特点与伴生能源利用,结合可再生能源发电与废弃矿井抽水蓄能,构建全清洁能源下的HCMES架构。其次,考虑到矿区生产全流程负荷的需求响应能力,考虑系统的能量平衡约束,提出全清洁能源下的高品质矿区能源系统优化配置模型。最后,以系统年平均综合成本最小化为目标,将原问题转化为混合整数线性规划模型,求解生成高品质矿区能源系统优化配置方案。以我国西部某年产煤量1200万t的矿区实际数据为实例,验证所提模型与方法的有效性,并分析可再生能源出力与生产负荷需求不确定性对系统优化配置结果的影响。算例仿真设置了4种矿区能源系统配置方式:不配置储能、配置抽水蓄能、配置电化学储能、配置抽水蓄能(不外购电能)。结果表明,所提出的HCMES相较于其他配置方式可减少电气一次设备投资11.11%,相较于方式3可降低年平均综合成本7.91%,且最多可减少矿区生产用能总二氧化碳排放量91.17%。展开更多
为获得压缩空气抽水蓄能(pumped hydro combined with compressed air energy storage system,PHCA)系统蓄能罐子系统在实际运行中具有较高能量密度与蓄能效率的参数配置,对系统中蓄能罐子系统进行热力学建模,分析了其压力配置、换热条...为获得压缩空气抽水蓄能(pumped hydro combined with compressed air energy storage system,PHCA)系统蓄能罐子系统在实际运行中具有较高能量密度与蓄能效率的参数配置,对系统中蓄能罐子系统进行热力学建模,分析了其压力配置、换热条件、流量配置对于蓄能罐子系统效率和能量密度的影响规律,结果表明:对于额定存储压力,总有与之对应的一个最优初始压力可以使得能量密度达到最大值,存储压力与最优初始压力的比值在2~3之间,对应压力配置的蓄能效率稳定在92%~93%之间;传热系数和存储时间在一定配置范围内会使系统陷入低效率区,在蓄能罐的设计中,应当评估出其换热能力避免低效率区;运行过程中,存储时间对于蓄能效率的影响较大,选择合适的水泵水轮机工作流量可以保证效率,在短存储时间时,采用的配置方法为高压缩、高膨胀流量,当存储时间变长后,应当同时减少压缩和膨胀流量。研究结果可为该系统的设计与运行提供理论依据。展开更多
基金Supported by a grant for a Key Research Project in Climbing Program from the State Science and Technology Commission of China。
文摘A mutually pumped phase conjugator is demonstrated with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate,in which the beams travel in a geometric path similar to the outline of a sickle.The maximum reflectivity is up to 168%.Faster response times are measured and are also simulated as a function of incident beam power ratio.Four available input geometries are found.The phase conjugation signals exist wide range of angular and positional alignment.No apparent cross talk is observed.The faster build-up process of phase conjugation beams is tentatively explained.
基金Supported by the Grant for a Key Research Project in Climbing Program from the State Science and Technology Commission of China.
文摘A mutually pumped phase conjugator with a novel photorefractive crystal of copper-doped potassium sodium strontium barium niobate is reported,in which both incoherent beams are incident upon the negative c face and they travel in geometric paths similar to the outline of two arches.The maximum reflectivity attains 21%.The tolerance of the output to both incident angles and positions is assessed.No apparent cross talk is observed.A cross-readout mechanism is also used to explain phase-conjugate reflectivity production.It is verified that the configuration can be realized easily for a crystal with two longer a sides.
基金This project is supported by Provincial Science Foundation of Hebei (No.01213553).
文摘An extended crowding genetic algorithm (ECGA) is introduced for solvingoptimal pump configuration problem, which was presented by T. Westerlund in 1994. This problem hasbeen found to be non-convex, and the objective function contained several local optima and globaloptimality could not be ensured by all the traditional MINLP optimization method. The concepts ofspecies conserving and composite encoding are introduced to crowding genetic algorithm (CGA) formaintain the diversity of population more effectively and coping with the continuous and/or discretevariables in MINLP problem. The solution of three-levels pump configuration got from DICOPT++software (OA algorithm) is also given. By comparing with the solutions obtained from DICOPT++, ECPmethod, and MIN-MIN method, the ECGA algorithm proved to be very effective in finding the globaloptimal solution of multi-levels pump configuration via using the problem-specific information.
文摘Six configurations are proposed in this paper to explore the gain and noise figure (NF) variations under the pumping power effect. I propose a new investigation of gain and NF at different EDFA configurations. Configurations such as SPSS, DPSS, DPSSF, TPDS, TPDSF, and QPDSF are designed, investigated and compared. A continuous progress of gain values is observed from SPSS to QPDSF, and a change of NF values related to configurations is recorded. The NF variations show different behaviors at different configurations. High gain of 59.49 dB and low NF value of 4.22 dB are recorded for the QPDSF configuration and low gain and low NF are recorded for the SPSS configuration.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61107086,61172010 and 61101058,Science and Technology Committee of TianJin(No 11JCYBJC01100)the National High Technology Research and Development Program of China(No 2011AA010205)the Open-Fund of the Key Laboratory of Opto-electronic Information Technology(Ministry of Education)at Tianjin University。
文摘We experimentally demonstrate a high power nanosecond pulsed terahertz(THz)-wave parametric oscillator(TPO)by using a wide pump beam.A surface emitted cavity configuration is employed to reduce the THz absorption in MgO:LiNbO_(3) crystal.The THz wave can be tuned from 1 THz to 3 THz.A maximum THz output energy of 438 nJ/pulse is achieved at 1.56 Hz using a 4.5-mm-diameter pump beam with a pulse energy of 226 mJ pump energy with the repetition of 10 Hz,corresponding to the energy conversion efficiency of 1.94×10^(-6).
文摘面向“30·60”双碳目标,矿区能源利用方式的绿色、经济、高效转型成为我国能源革命的迫切需求。西部矿区拥有丰富的可再生能源资源禀赋,但仍面临着可再生能源就地消纳困难,电力设备投资成本高、利用率低以及外送输电通道有限的困难。为提升矿区用能清洁化程度,提升矿区能源供给的稳定性与可靠性,增强矿区对外部电网的支撑能力,提出全清洁能源下的高品质矿区能源系统(High-quality Coal Mine Energy System,HCMES)及其配置优化方法。首先,考虑西部矿山综合能源系统的负荷特点与伴生能源利用,结合可再生能源发电与废弃矿井抽水蓄能,构建全清洁能源下的HCMES架构。其次,考虑到矿区生产全流程负荷的需求响应能力,考虑系统的能量平衡约束,提出全清洁能源下的高品质矿区能源系统优化配置模型。最后,以系统年平均综合成本最小化为目标,将原问题转化为混合整数线性规划模型,求解生成高品质矿区能源系统优化配置方案。以我国西部某年产煤量1200万t的矿区实际数据为实例,验证所提模型与方法的有效性,并分析可再生能源出力与生产负荷需求不确定性对系统优化配置结果的影响。算例仿真设置了4种矿区能源系统配置方式:不配置储能、配置抽水蓄能、配置电化学储能、配置抽水蓄能(不外购电能)。结果表明,所提出的HCMES相较于其他配置方式可减少电气一次设备投资11.11%,相较于方式3可降低年平均综合成本7.91%,且最多可减少矿区生产用能总二氧化碳排放量91.17%。
文摘为获得压缩空气抽水蓄能(pumped hydro combined with compressed air energy storage system,PHCA)系统蓄能罐子系统在实际运行中具有较高能量密度与蓄能效率的参数配置,对系统中蓄能罐子系统进行热力学建模,分析了其压力配置、换热条件、流量配置对于蓄能罐子系统效率和能量密度的影响规律,结果表明:对于额定存储压力,总有与之对应的一个最优初始压力可以使得能量密度达到最大值,存储压力与最优初始压力的比值在2~3之间,对应压力配置的蓄能效率稳定在92%~93%之间;传热系数和存储时间在一定配置范围内会使系统陷入低效率区,在蓄能罐的设计中,应当评估出其换热能力避免低效率区;运行过程中,存储时间对于蓄能效率的影响较大,选择合适的水泵水轮机工作流量可以保证效率,在短存储时间时,采用的配置方法为高压缩、高膨胀流量,当存储时间变长后,应当同时减少压缩和膨胀流量。研究结果可为该系统的设计与运行提供理论依据。
