槽式集热器(火用)效率分析和互补电站镜场设计

为实现给水加热型互补发电系统中太阳岛与动力岛更好耦合,本文建立了槽式集热器(火用)效率的热力学模型,分析了200 kW典型集热器(火用)效率随运行参数的变化规律:平均辐照600W/m2时最大效率为33%左右,最佳温度范围为250～350°C,并进行了实验验证,最后分析了互补发电系统集热场(火用)效率在设计辐照和偏离设计...     

槽式集热器(火用)效率分析和互补电站镜场设计

为实现给水加热型互补发电系统中太阳岛与动力岛更好耦合,本文建立了槽式集热器(火用)效率的热力学模型,分析了200 kW典型集热器(火用)效率随运行参数的变化规律:平均辐照600W/m2时最大效率为33%左右,最佳温度范围为250～350°C,并进行了实验验证,最后分析了互补发电系统集热场(火用)效率在设计辐照和偏离设计...     

太阳能与燃煤互补电站镜场布置研究

针对330 MWe太阳能与燃煤互补发电系统,利用抛物槽式太阳能集热系统汇聚300℃左右的太阳热能,替代蒸汽抽汽加热给水,对系统中太阳能镜场的布置及优化进行了深入研究.基于集热场运行工况,开发了太阳能集热场设计的模拟计算程序。探讨了镜场遮挡损失与集热器间距的关系;研究传热工质流速、太阳辐照强度对集热场布置的影响规律.在设计工况下,镜场集热量49 MW,镜场面积为1.39×10~5 m~2,占地面积4.19×10~5 m~2,镜场和场地面积比达到33.2%,优于当前槽式太阳能单独热发电22%~25%的水平.本文研究结果为太阳能与燃煤互补电站太阳能岛的设计提供了依据。     

太阳能辅助不同容量燃煤机组热性能分析

本文针对槽式太阳能辅助不同容量燃煤机组的互补耦合发电系统,建立槽式太阳能集热场以及互补系统的数学模型,分析互补发电系统在典型工况以及年热力性能,并以此为基础研究集热场面积及蓄热对互补发电系统热力性能的影响。其结果表明,典型工况下低功率容量的耦合机组节煤效果更好,更能在较小的集热场面积下达到较高的热电效率;而从年性能的角度看,蓄热装置的引入会使互补发电系统的热性能显著提高。     

太阳能热化学互补发电系统的变辐照性能研究

本文基于10 kW中低温太阳能与甲醇热化学互补发电实验平台,采用不同太阳辐照强度与吸收反应器内甲醇裂解反应、甲醇重整反应两种化学反应的有机集成,提出了一种新颖的变辐照与不同化学反应相匹配的主动调控新方法,针对不同典型日太阳辐照强度偏离设计值,探讨了热化学互补发电系统变辐照工况的特性规律。研究结果表明,在中低温太阳能热化学互补发电系统中,与采用单一的太阳能驱动甲醇裂解反应相比,本文提出的主动调控方法使互补系统的日均太阳能净发电效率从30%提高到36%,更接近设计工况,有效提高了甲醇燃料化学能的梯级利用程度。该方法为减小单位镜场面积、提高太阳能年均净发电效率提供了有效途径。     

太阳能与燃煤互补系统变工况热力性能研究

针对新疆昌吉地区典型330 MW燃煤机组提出了一种利用抛物面槽式太阳能聚光集热器进行互补发电的改造方案。依据昌吉地区的气象条件及燃煤电站全年实际运行性能参数,通过对互补系统在不同太阳辐照强度及不同汽轮机负荷下变工况性能的模拟分析,获得了互补系统在典型日及典型年的热力性能,揭示了关键运行及性能参数的变化规律。结果表明,互补系统年均净发电效率为15.0%,优于现有单一太阳能热发电技术。本文对传统燃煤电站的互补方案的设计和实施具有一定的参考价值。     

槽式太阳能集热与化学热泵耦合的复合发电系统

本文提出了一种抛物槽式太阳能集热与化学热泵耦合的复合发电系统,对其热力性能进行了分析,并研究了反应器中反应蒸汽温度、镜场加热给水温度等关键运行参数对系统性能的影响。研究了太阳能特征参数对系统性能的影响规律,分析了太阳直射辐照强度(DNI)高于设计工况时,储能材料氧化钙的量与DNI的关系。设计工况下,系统输出功335.7 MW,热效率为30.4%,发电效率23.6%。所提出的系统,为解决槽式太阳能单独热发电系统蒸汽参数低导致动力循环热效率低的难题提供了新途径。     

新型太阳能与燃气轮机联合循环互补系统集热场优化研究

新型太阳能与燃气轮机联合循环互补系统根据不同类型的太阳能集热装置的集热特性,实现其与燃气轮机联合循环系统的梯级互补,将太阳能直接蒸汽发生系统(DSG)与高压蒸汽蒸发过程耦合,同时将低压蒸汽的生成过程与热管式真空管集热器进行耦合。本文主要针对真空管集热场中集热器行间距及倾斜角等参数的优化问题,开展其对全年有效太阳热能及平均集热效率影响规律的研究。     

太阳能辅助空冷机组互补发电系统热性能研究

以槽式太阳能辅助600 MW直接空冷燃煤机组互补发电系统为研究对象,依据机组装机容量选择与其匹配的集热场面积,建立互补发电系统模型,对THA工况与75%THA工况时功率增大运行模式下取代第3级高加和取代2、3级高加这两种取代方式进行热性能计算分析。在此基础上,为进一步分析气象因素对互补发电系统热性能的影响,以THA工况功率增大运行模式下取代第3级高加抽汽为例研究,结果表明:DNI越大、风速越高、环境温度越低,互补发电系统的热力性能越好。     

30m~2槽式太阳能集热器性能模拟研究

本文针对30 m~2槽式太阳能集热试验装置,对太阳能集热器的性能进行了模拟。分析了太阳能集热器光热转化过程,建立了太阳能能量转换与传递模型,并开发了模拟计算程序,研究了集热器关键结构参数和运行参数对集热性能的影响规律。具体考察了太阳辐照强度、工质流量、环境风速、吸热管管径等对集热效率的影响。结果表明:太阳能集热器的集热效率随太阳辐照强度的增加而增大,随工质流量的增加而增大,存在最佳的吸热管管径使得集热效率最大。研究结果将为太阳能集热器的设计提供参考依据。     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

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.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

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.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.     

Design optimization of highly sensitive LSPR enhanced surface plasmon resonance biosensors with nanoholes

For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters.     

Polymer gratings based on photopolymerization for low-order distributed feedback polymer lasers

Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.     

A novel methodology for photometric compensation of projection display on patterned screen

We propose a novel methodology based on the projector-camera (ProCam) system to address the photometric compensation issue for the projection display on the patterned screen.The patterned screen is treated as the combination of a perfect white screen and a color modulator.The perfect white screen is used to automatically and accurately characterize the ProCam system offline using the polynomial model,and the parameters of the color modulator can be efficiently recovered by employing only two gray images based on the linear reflectance model.The experimental results show that the color artifacts of the display image can be greatly improved with this methodology,which demonstrates its feasibility and validity in the photometric compensation.