太阳能吸附式冰箱性能测试与分析

研制了一种简易太阳能吸附式冰箱,在昆明气候条件下,测试了其年运行性能。测试结果表明,在太阳辐射强度为15-23MJ／m2·d的条件下,每平方米集热面积的制冰量约为3.2-6.5kg／m2·d,系统制冷系数COP约为0.083-0.127。对该太阳能吸附式冰箱而言,较为适宜的气候条件为太阳辐射大于15MJ／m2·d。     

直膨式太阳能热泵热水器运行特性的实验研究

本文针对自行设计、建造的“直膨式太阳能热泵热水器”实验样机进行了春季运行工况下的实验研究,并对其运行特性进行了详尽的分析．实验结果表明,在环境温度均值20．6℃、太阳辐射强度均值954．59 W／m2的室外气象条件下,将150升水从13．4℃加热到50．5℃只需要94分钟,热泵供热性能系数达到6．61．即使在环境温度为17．1℃的雨夜天气,热泵性能系数仍能够达到3．11．通过对典型工况下太阳能集热板的集热效率和过热度进行分析发现,如果用电子膨胀阀取代热力膨胀阀对供液量进行实时调节,可以进一步提高热泵的性能系数和系统运行的稳定性．     

用于住宅建筑的太阳能吸收式空调性能分析

夏季太阳能辐射强度与空调负荷有很好的一致性,这使得太阳能辅助空调具有独特的优点。根据郑州地区夏季太阳辐射和空调负荷特点,针对某一太阳能辅助吸收式空调系统进行了理论分析,该系统供冷对象为200m2别墅,采用60m2平板式太阳能集热器和一个带有辅助加热装置的集热水箱作为热源。在发生器温度为70—100℃,蒸发温度5—15℃的范围内计算了系统性能系数和太阳能利用率。计算结果表明,在5—9月份,太阳能可以提供建筑冷负荷的76—122%。     

定转速独立光伏直驱冰蓄冷初步实验研究

本文探究了独立光伏系统在不使用蓄电池和逆变器的情况下,利用光伏板产生直流电驱动定转速压缩机进行蒸气压缩制冷循环制冰蓄冷,将太阳能以冰的形式进行存储的储能方式.本文对定转速独立光伏直驱冰蓄冷系统进行了实验研究,分析实验数据得到压缩机启动和停止对应的最低太阳辐照强度.进一步对拉萨、北京、南京三个地区分别应用定转速独立光伏直驱冰蓄冷装置进行了全年模拟运行,分析了该装置在不同气象类型地区的适用性.     

直膨式太阳能热泵供热水系统的性能研究

本文对直膨式太阳能热泵系统进行了实验研究,并对其热工性能及影响因素进行了理论分析,结果表明该系统 的热工性能主要受太阳辐射强度、环境温度、集热面积、水箱容积及压缩机转速等因素的影响,在此基础上提出了系统设 计和运行控制等方面的改进意见。     

直膨式太阳能热泵热水器的实验研究

建立了直膨式太阳能热泵热水器实验样机,该样机采用裸板式太阳能集热器作为蒸发器。在室内模拟光源(0～1000W/m2)下,对该热水器进行了性能测试,得出热水平均加热功率为1.04 kW,热泵平均COP为4.18。通过对实验数据加以整理和分析,得出了热水温度、集热/蒸发板温度、热水加热功率及热泵COP随太阳辐射强度及运行时间的变化规律,并提出了热泵COP的改善措施。     

太阳能甲醇分解吸收-反应器研制与实验研究

利用中温太阳能为甲醇分解的吸热反应供热,可以将中温太阳能转化为合成气燃料的化学能,同时提高燃料热值和太阳能的可用性,还可以实现太阳能与化石燃料的互补.本研究提出了太阳能热化学系统的一体化设计原则,建立了综合考虑太阳能集热、反应动力学和反应器结构参数的太阳能甲醇分解反应器的理论分析模型,并首次研制了5 kW热功率的抛物槽式太阳能甲醇分解一体化实验装置.太阳能甲醇分解的实验结果表明太阳能集热器可以为甲醇分解提供200～300 ℃的反应温度,在辐照300～800 W/m2,甲醇进料量为0.5～4l/h条件下,甲醇转化率可以达到50%～95%,投射到吸收-反应器上的太阳能转换为燃料化学能的效率可以达到30%～60%,具有良好的甲醇分解和太阳能转换性能.研制的实验装置体现了一体化设计特征,同时理论分析结果与实验结果也具有很好的一致性.本文研究成果将为开拓太阳能与化石能源互补的能量系统提供理论支撑和实验数据.     

圆柱面菲涅耳镜太阳能集热系统研究

本文介绍了一种利用圆柱面菲涅耳镜组成的太阳能集热系统,该系统主要由菲涅耳聚光器、二次聚光器、太阳跟踪器、换热器和负载等部件组成。介绍了圆柱面菲涅耳透镜的设计思路,并采用工业化方法研制成功了0.65m×1 m的线聚焦圆弧形菲涅耳透镜,并利用该透镜搭建太阳能集热系统研究平台。在实际天气下对该系统性能进行了测试,结果表明,该系统可以实现集热温度200℃以上,在集热温度小于100℃时,中午10:00.14:00时间段,该系统的集热效率可以达到近60%,午后14:00-15:00时段,效率可以达到近38%。说明该系统在一天之内有6 h高效运行。     

太阳能辅助燃煤发电系统蓄热运行策略优化

太阳能辅助燃煤发电已经被证明是一种有效利用太阳能的发电方式。与纯太阳能光热发电系统不同,太阳能辅助燃煤互补发电系统(下简称互补发电系统)中采用不同的蓄热运行策略将对互补系统的性能产生显著影响。本文针对槽式互补发电系统,建立了槽式太阳能集热场以及互补系统的数学模型,采用了真实的气象数据进行仿真模拟,研究分析了互补发电系统的年性能,得出了不同太阳能倍数、蓄热小时数对互补系统的太阳能发电成本LCOE的影响规律,并据此优化蓄热运行策略。其结果表明:三种策略中,削峰填谷策略是最适合互补发电系统的运行策略,在0.5蓄热小时数、1.2太阳能倍数下,其太阳能发电成本取得极小值,为0.064$/kWh。     

多曲面复合聚焦槽式太阳能集热器的研究

对一种多曲面复合聚焦槽式太阳能聚光集热器进行了理论与实验研究,介绍了其工作原理,对其重要的设计参数进行了计算和优化,给出了大致的取值范围.该新型槽式聚光集热器能够利用多曲面组合实现对太阳光反射聚焦,并具有在反射面上不留阴影、改善高温太阳能接收器的工作性能.实验表明,装置在低温段运行效率在45%以上.在高温段(≥80℃)...     

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.     

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.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.