小型风光互补发电演示装置

研制了适用于大学物理演示实验教学的小型风光互补发电演示装置,该装置由叶片、风力发电机、光伏太阳能电池板、控制器、蓄电池、逆变器、负载等几部分组成.整个系统以光电互补控制器为核心,经由风力发电机与光伏太阳能电池板将风能和太阳光能转变为电能,并将其储存于蓄电池中供负载使用.该装置展示了风力发电系统的组成,演示了风力发电原理和相关空气动力学原理.     

桨距角对风力发电机输出功率影响实验装置的研究设计

利用风力发电原理,制作简易定桨距风力发电实验装置。测量风力发电装置输出功率及风能利用系数,利用测量结果探究同风速下风力发电机有关运行参数随桨距角改变的变化规律。     

直驱型永磁同步风力发电机组中混沌运动的反步自适应控制

以直驱型永磁同步风力发电机为研究对象, 推导了发电机在参数不确定以及风速扰动情况下的数学模型,验证了系统在某些参数及工作条件下会呈现出混沌属性. 并提出了直驱型永磁同步风力发电机混沌运动下的基于反步自适应控制算法,并对其进行了仿真, 仿真结果表明,所提出的算法对于具有参数不确定以及风速干扰的直驱型风力发电系统具有较好的鲁棒性. 关键词： 风力发电 直驱型永磁同步风力发电机组 混沌控制 反步自适应控制     

微型风力发电演示仪

设计制作了一种基于风光互补原理的微型风力发电演示仪.该仪器由风力发电机、光伏太阳能电池板、控制器、蓄电池、负载等各部分组成.整个系统以控制器为核心,由风力发电机、光伏太阳能电池板把风能和光能转变为电能并储存于蓄电池中供负载使用.该仪器作为演示实验仪不仅小型、直观、模块化和操作简便,而且演示内容突显物理与工程相结合的知识...     

永磁同步风力发电机随机分岔现象的全局分析

永磁同步风力发电机在运行过程中不可避免地会受到风能的随机干扰,本文建立了在输入机械转矩存在随机干扰情况下永磁同步风力发电机的数学模型,采用胞映射方法分析了随机干扰强度变化时系统全局结构的演化行为,并通过数值模拟对理论分析进行验证.研究结果表明,随着随机干扰强度的增大,系统中会出现随机内部激变和随机边界激变,即由于随机吸引子与其吸引域内的随机鞍发生碰撞而产生的随机分岔现象和由于随机吸引子与其吸引域边界发生碰撞而产生的随机分岔现象.研究结果揭示了随机干扰对永磁同步风力发电机运行性能影响的机理,为永磁同步风力发电系统的运行和设计提供了理论依据.     

纽约将在高空设置风力发电机

我们都知道,风能是一种重要的可再生绿色能源。当地面附近的风能正在逐步得以开发之时,科学家已经不满足于在地面上获得的这些成绩了。近年来,一些能源科学家开始尝试高空风力发电。最近,纽约的风力发电工程师准备在高空设置风力发电机（图1）。     

水平轴升力型风力发电机叶片数量叶片倾角与输出功率的关系研究

旨在探索水平轴风力发电机的风叶数量、风叶倾斜角度与输出功率之间的关系,通过此关系的探究,指导风力发电机的设计和应用。     

以全面质量管理观引导风能发电

1风能发电的趋势 ①风能发电是新能源发展的重要途径风能作为一种可再生能源,具有取之不尽,用之不竭,无污染的特性．风力发电相对太阳能、生物质等可再生能源技术更为成熟,成本更低,对环境破坏更小．在过去20多年里,风力发电机技术不断取得突破,规模效益日益明显．使用风能发电已成为世界可再生能源发展的重要途径．     

风力发电实验仪

研制了风力发电实验仪,并利用该实验仪探究了风速、风机转速、发电机输出电动势之间关系,测量了风机的风能利用系数,展示了风力发电涉及的工程技术问题,即:在额定风速之下,采用追踪最佳叶尖速比的调节方法可最大限度利用风能;当风速超过额定风速,用变浆距调节方法可实现风力发电平稳输出.     

风力发电机自循环蒸发内冷系统稳定性的研究

自循环蒸发内冷系统的冷却效率高,可以实现无泵自循环,运行安全可靠,基本免维护,因此适合在大型风力发电机中使用.蒸发内冷系统的稳定性对风力发电机的安全运行十分重要,本文基于非线性分岔理论及其数值延拓法,对自循环蒸发内冷系统应用于风力发电机的的静态稳定性进行了深入研究.获得了系统静态分岔解图,分析了系统演化特性,同时分析了系统分岔现象的参数效应.搭建了实验平台,通过实验观测到了自循环蒸发内冷系统的静态分岔现象,验证了理论计算的正确性.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.