千瓦级PEMFC电堆的研制

使用表面改性的金属铝板做双极板,成功组装了含30个质子交换膜燃料电池(PEMFC)单电池的电堆。H2、空气反应气均采用外增湿,使用循环冷却水排出电堆产生的热量。分别使用Nafion115膜和John-MatthyPt/C作为电解质和催化剂,其中Pt载量为0.4mg/cm2。电堆工作温度为室温至100℃,H2与空气工作压力比为0.20MPa/0.22MPa,电堆输出功率为1~1.3kW,输出电流为40~80A,输出电压为26~20V,电极工作电流密度为200~375mA/cm2,电堆能量转化效率为51%。     

Electron beam pumped argon-excimer laser using an unstableresonator

An unstable resonator was used for an e-beam pumped argon-excimer laser in the VUV-spectral region, for the first time to our knowledge. Adoption of the unstable resonator achieved successful operations of the high output energy of 28 mJ without any damage of the resonator mirrors. Beam divergence of the argon-excimer laser output was measured with a beam profiler, which was developed in our laboratory, It was found that the output beam involved a large ASE output. The maximum focused fluence at the center of the output beam was measured to be 42 mJ/cm². The coherence of the argon-excimer laser was degraded by the ASE, which was caused due to high gain condition of the argon-excimer laser     

VUV laser in the Lyman band of molecular hydrogen pumped by fstitanium-sapphire laser pulses

We report lasing at 160 nm in the Lyman band of molecular hydrogen. The laser is pumped by 200 mJ/150 fs pulses from the ATLAS titanium-sapphire laser at our institute. The pump pulses are focused at an angle of incidence of 60° onto a 9-cm-long gold target to a line focus, generating traveling-wave excitation. With 80 mbar of hydrogen in the target chamber we measure an average gain of 1.1 cm^-1 and achieve a total gain-length product of 10. The evaluation of the far-field pattern shows that the beam originates from a region with an electron density of 5×10¹⁵ cm^-3. A simple model of the H₂ laser is presented which explains the main part of our observations and supports a pump mechanism of photoelectron pumping     

Ultrabroad-band Raman amplifiers pumped and gain-equalized bywavelength-division-multiplexed high-power laser diodes

This paper reviews recent progress in broad-band Raman amplifiers for wavelength-division-multiplexed (WDM) applications. After the fundamentals of Raman amplifiers are discussed in contrast to erbium-doped fiber amplifiers, a new technique called “WDM pumping” is introduced to obtain ultrabroad and flat gain in Raman amplifiers only using WDM diode pumps. The design issues of this technique are then developed to realize outstanding performances such as 100 nm of flat gain bandwidth, 0.1 dB flatness over 80 nm, and so forth     

Design of stabilized laser for optically pumped atomic frequency standards

The influence of a stabilized laser's fluctuations in an optically pumped atomic frequency standard is considered. It is important to use a laser with narrow linewidth and select the modulation frequency where the laser's free‐running frequency fluctuation at twice the modulation frequency is the lowest. Employing these considerations, the stabilized laser for our optically pumped cesium beam frequency standard is designed. © 2001 Scripta Technica, Electr Eng Jpn, 136(2): 31–37, 2001     

Failure statistics for diode laser array modules and replacement model in large-scale laser systems

This paper presents a methodology for synthesizing diode-laser array module failure statistics from the failure statistics of constituent diode laser arrays. In addition, a model is elucidated for analyzing replacement strategies of systems containing large numbers of diode laser array modules. Simulations reveal the dependence of synthesized module failure statistics and replacement characteristics on module size and failure statistics of the constituent diode laser arrays.     

Inherently mode-hop-free distributed Bragg reflector (DBR) laser array

An inherently mode-hop-free tuning of 4.5 nm was achieved with a short-active-region distributed Bragg reflector (DBR) laser. The DBR laser contains no phase-adjustment electrode, which greatly simplifies the tuning. Fast tuning of several nanoseconds and error-free operation for 2.5-Gbit/s direct modulation were also observed. A 4-ch array of short-active-region DBR lasers achieved wavelength tuning of 12.5 nm.     

基于继电器阵列的激光功率自动换档测量方法

传统的激光功率测量方法是将光电探测器输出的光电流接人到由运算放大器搭建的I/V(电流/电压)转换电路中,通过手动开关或模拟多路开关切换不同的反馈电阻接入电路从而实现多档位大量程的测量.针对手动切换档位的操作复杂性以及多路模拟开关内阻大、承载电流小等缺点,设计了一种利用高灵敏度信号级继电器阵列控制反馈电阻切换实现的大量程激光功率自动换档测量方法.经实验测试,该方法相比于传统切换档位测量方法更为精确、快捷、可靠.     

千瓦级质子交换膜燃料电池

组装了一台40节千瓦级质子交换膜燃料电池。双极板采用复合板,阴极侧流场采用蛇型流场,而阳极侧流场采用平行沟槽流场。电极采用杜邦公司的Nafion1135质子交换膜热压而成,碳载铂为电催化剂,铂担量为0.4mg/cm2,电池组工作温度范围为室温至80℃,工作压力pO2,空气/pH2=0.20MPa/0.19MPa,以氧气为氧化剂时电池组输出最大功率为2 5kW;以空气为氧化剂时电池组输出最大功率为1.2kW。     

Development of diode‐pumped solid‐state laser HALNA for fusion reactor driver

The diode‐pumped slab laser for inertial fusion energy driver has been demonstrated, which produces the 1053‐nm output energy of 10 J at 10 Hz. The glass slab laser amplifier has been pumped by quasi‐CW 290‐kW AlGaAs laser‐diode arrays at 803 nm. The optical system can compensate for thermal effects by use of zigzag optical propagation, image‐relayed telescope, and 45^° Faraday rotator. The output energy of 10.6 J at 1 Hz with the optical‐to‐optical conversion efficiency of 19.9% has been successfully obtained. Also, the 10‐Hz operation has been performed with an output energy of 5.1 J. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 27–35, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20288     

A 380-mW 7-MHz cerium LiLuF laser pumped by the frequency doubledyellow output of a copper-vapor-laser

We report a high average power Ce:LiLuF laser pumped by the second harmonic of the yellow output from a copper vapor laser. This cerium laser yielded up to 380 mW at a pulse repetition frequency of 7 kHz at the peak lasing wavelength of 309.5 nm, with a slope efficiency of 50%. In addition, single prism tunability was obtained from 305.5 to 316 nm and from 322 to 331.8 nm, Preliminary investigation into color center behavior has been performed involving crystal cooling, He-Ne pump probe experiments and antisolarant pumping     

Passive optical limiting of picosecond-nanosecond laser pulsesusing highly nonlinear organic liquid cored fiber array

We present a detailed account of theoretical and experimental studies of nonlinear molecular photonic processes accompanying the propagation of short intense laser pulses through an organic liquid cored fiber array. The theory takes into account two-photon absorption, excited state absorption, and dynamical evolution of the molecular energy level populations and the laser intensity. The coupled dynamical equations for the molecular energy-level populations and laser intensity are solved numerically using experimentally observed molecular and optical parameters. Experimentally obtained optical limiting results are analyzed along with nonlinear absorption and pump-probe studies of other nonlinear optical processes occurring in the fiber core. It is found that in the nanosecond time regime, besides excited state and two-photon absorption, thermal and density effects also contribute significantly to the optical limiting performance of the constituent fiber     

Ultralow threshold 1.3-μm InGaAsP-InP compressive-strainedmultiquantum-well monolithic laser array for parallel high-densityoptical interconnects

An ultralow-threshold 1.3-μm InGaAsP-InP 10-element monolithic laser array is achieved through careful optimization of a strained multiquantum-well active layer, especially the amount of strain, the well thickness, the barrier thickness, the number of wells, and the active laser width. This array has a record-low threshold current, highly uniform threshold current characteristics (1.3±0.09 mA and slope efficiency of 0.37±0.01 W/A), extremely low operating current of 14 mA under 5-mW output power, and long-term reliability. This array is suitable as light sources for a parallel high-density optical interconnection system. In addition, a record low CW threshold current of 0.58 mA at 20°C and 1.62 mA at 90°C, as a long-wavelength laser, is obtained by employing a short cavity (100 μm) uith high-reflection coatings     

Resonantly pumped eyesafe erbium lasers

The viability of high-power and high-energy, direct eyesafe emission from bulk erbium lasers has recently been demonstrated. In this paper, we present a review of eyesafe erbium lasers that are resonantly pumped by both fiber and diode lasers. High brightness pumping with a 1.53-/spl mu/m erbium fiber laser has yielded 60 W of continuous wave (CW) output, 10 W of repetitively Q-switched output, and as much as 16 mJ of pulse energy. Diode laser pumping has yielded 38 W of quasi-CW output and >40 mJ of Q-switched output.     

Performance analysis of a time-division-multiplexed fiber Bragggrating sensor array by use of a tunable laser source

The results of an investigation of the performance of a time-division-multiplexed (TDM) fiber Bragg grating (FBG) sensor array using a tunable laser source are reported. The system performance is found limited by the extinction ratio of the optical pulse modulator used for pulse amplitude modulation. Formulas that relate the crosstalk to the extinction ratio of the optical pulse modulator, the modulation parameters of the tunable laser, and the optical path differences among sensing channels are derived. Computer simulation shows that an array of 20 FBG sensors with 3 με resolution can be realized with a commercially available single Mach-Zehnder type optical pulse modulator of -35-dB extinction ratio     

京津唐电网第一个百万千瓦风电基地并网运行分析

京津唐电网第1个百万千瓦风电基地总容量为1300MW,由12个风电场组成,并网线路总长度为605km,到并网点的最长送电距离达189km,计划于2010年前后全部并网运行。根据电网实际运行参数,针对风电场并网后电网的稳态运行和故障情况进行全面的仿真计算分析。对并网线路产生的充电功率、容性及感性无功补偿装置的配置、风电机组有功出力变化引起并网线路潮流波动、系统故障对风电机组的影响及电压的控制措施、风机提供的短路电流等分别进行了研究,提出满足电网安全运行的具体建议。     

浅谈抽水蓄能机组可靠性管理

抽水蓄能机组是近年来发展较快的一种水电机组，其区别于一般水电机组的最大特点在于多了抽水工况，而目前如何对这种机组进行可靠性管理尚未有一套规范的办法。为此，以广州蓄能水电厂为例，结合多年的工作经验，对抽水蓄能机组如何进行可靠性管理做了一些探讨和分析。     

二极管激光器驱动电源的研制

为满足DPL(二极管泵浦固体激光器)表演系统中驱动电源系统的要求,设计了可连续或准连续工作的激光二极管驱动电源,采用TEC(半导体制冷器)作为二极管和倍频晶体的温度调节。二极管驱动电流达3A,当脉冲调制时,输出自动高于连续输出的30%。TEC温度控制精度达0.1℃。电源还具有过流、过热保护,防静电和浪涌等功能。     

新型大功率级联式二极管H桥整流器

针对传统中压变频器中移相变压器体积大、接线多、重量大的问题,提出了一种级联式多电平整流电路拓扑。该拓扑无需采用工频移相变压器,而是由二极管整流桥和级联Boost电路模块单元构成,可实现单位功率因数整流、级联模块单元的稳压输出和均压控制。讨论了拓扑的基本工作原理、稳态特性,对其关键参数(升压比,负载不平衡度和电感值)进行了推导,并给出了相应的控制策略。仿真与实验结果验证了所提拓扑和控制策略的可行性。