基于太阳能甲醇分解的冷热电联产系统

本文从太阳能与化石能源综合互补利用的思路出发,将中低温太阳能利用与冷热电联产系统有机结合,研究提出了一种太阳能甲醇分解冷热电联产系统.该联产系统能够提高现有太阳能系统在中低温范围内的能源利用效率,并能部分替代化石能源.(火用)分析表明,系统节能关键在于太阳能供热甲醇分解过程有效减少了燃烧过程能量损失.本文的研究可为太阳能系统的发展及化石能源的替代提供新的思路.     

R-113-空气系膜状凝结放热的实验研究

近年来学术界对蒸汽-不凝性气体物系凝结问题的研究十分重视.认为它是节能和能源技术开发中一项重要的研究课题.在能源(包括火电、制冷、热泵、地热、余热、太阳热及海洋热等)转换系统中,由于系统内残留空气、工质中溶解的空气以及长期运行工作流体受热可能分解出的不凝性气体的存在,将使凝结换热装置的传热性能大幅度下降。本文     

冷库节能潜力分析

食品冷冻冷藏属高耗能行业,长期存在着大量不重视能源管理与浪费能源的现象。分别从隔热材料、压缩机能量调节方式、冷凝器系统、油系统以及运行管理等方面,分析了冷库的节能潜力。针对冷库工程设计、工程施工及常规管理工作的技术要求和需要,提出了相应的节能措施。这些措施对冷库企业降低生产成本、节约能耗,具有现实意义。     

二氧化碳利用新进展:二氧化碳直接高选择性合成汽油燃料

<正>随着人类社会的不断发展,人们对自然资源的依赖程度逐渐增大,其消耗速度也在不断增长。然而,不断增长的能源消费也对环境带来了诸多的负面影响,其中CO_2的排放问题越来越受到政府、公众、企业界以及学术界的关注。目前,"减排"已不仅仅是一个环境热点,而是已经成为了一个威胁人类生存和发展的,达到国际关系高度的复杂问题。中国政府高度重视CO_2减排问题,国家主席习近平在巴黎气候大会重申了中国此前做出的承诺,中国将于2030年左右使     

基于相邻节点协作的无线传感器网络安全协议

在网络通信技术不断发展的今天,无线传感网络已日臻完善和成熟,被广泛地应用于社会各行业领域之中,且随着其技术的不断突破,现已同通信技术与计算机技术一道成为我国信息技术的三大支柱产业,在产业进步与经济发展方面扮演着极其重要的角色.但由于无线传感技术是以大量的静止的或移动的传感器以自组织或者多跳的方式构成的无线网络作为工作的基础,因此很容易受到外部环境的影响而无法正常地工作.因此,如何设计出一种高效节能且安全系数较高的无线传感网络安全协议成为当今信息技术领域的重要课题,也是难题.本文试从无线传感网络协议的工作模式以及网络密钥管理的角度出发,阐述基于相邻节点协作的无线传感器网络密钥管理方案的优势并进行安全性分析,希望能实现无线传感网络安全协议的突破.     

电化教学手段在物理教学中的作用

随着科学技术的发展和人民生活水平的不断提高,电脑在人们的日常生活、工作、学习中已经成为一种不可缺少的常用工具.对学校而言,建立先进的电化教学网络和要求教师运用电化教学手段进行授课已经成为学校教学改革的中心任务.这是时代进步的标志,使传统的教学方法找到了更为有效的辅助手段,大大地提高教学质量,为实现对     

专家：光伏产业发展前景不容置疑

2011年以来,受国际金融危机和贸易保护主义影响,中国光伏制造业处在严重低迷期,形势严峻。在中国科学院日前举办的太阳能发展战略暨与企业交流研讨会上,中国可再生能源学会副理事长赵玉文认为：从各国的节能减排目标和联合国的《可再生能源特别报告》看,     

铁电固态热机的物理机制及应用

能源是当今举世瞩目的重大问题．研制新型能源材料,探索节能新途径是物理学和材料科学研究中的重要课题．早在二十年代就有关于铁磁体作为工作物质的致冷机和热机（热引擎）的设想和实验[１,２］,但将铁电体用于致冷机和热机的研究则是近十几年才发展起来的．这种热机的特点是,工作物质是在居里温度附近工作的铁电介质．热机通过温差电效应和热电效应相结合,将热能直接转变为电能,而不要任何普通热机所需的复杂中间机械系....     

"创新中国"时代背景下创新创业教育与应用物理学专业教育的融合

介绍了我国高校创新创业教育现状,说明了创新创业教育与物理学专业教育相融合的内涵,通过融合创新创业理论课程体系的建设和实践,以创新创业能力培养为核心的多元化实验、实践教学体系的构建,以项目化的创新创业成果的培育为手段,使学生的创新意识和创新思维得到不断的强化和训练,创新人才的培养才得以实现.     

附加碳税的综合能源系统优化调度分析

针对节能减排的能源转型发展要求,构建了结合可再生能源以及储能装置的综合能源系统模型。引入碳税将CO₂排放的环境问题转换为经济成本问题并建立以经济成本最低为目标函数的优化模型。利用改进的猫群算法对碳税为50 CNY/t的综合能源系统冬夏两季典型日优化调度,对比传统的冷热电三联产(CCHP)系统,综合能源系统的CO₂排放在夏季是CCHP系统的48.93%,冬季为50.86%;节能率在夏季可达到36.33%,冬季能达到23.65%;与没有引入碳税的综合能源系统相比,冬夏两季典型日共减少了40.28%的CO₂排放。对不同碳税下减排效果与经济性的分析,现阶段采用中等的碳税水平(50 CNY/t)更为合理。     

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.     

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.     

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.     

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.