激光光声光谱法检测甲醇内燃机燃烧排放气体成分的研究

介绍激光光声光谱法检测以甲醇为燃料的内燃机燃烧排放的气体成分，证明了激光光声光谱气体分析装置是内燃机燃烧诊断的有效工具之一。     

粒度测试的典型方法及其在火电厂煤粉测量中的应用

介绍了粒度测量的基本知识和评价粉体粒度的重要指标。列举了筛分法、显微镜法、沉降法、电阻法、光散射法的基本原理及特点。举例说明了筛分法和激光粒度法在火电厂煤粉颗粒的实际测量当中的基本步骤和注意事项,并对测量结果进行了分析。     

光声技术在内燃机排放测量中的应用

先声技术是一种新型的分析技术,它具有灵敏度高、速度快和装置简单等优点。本文介绍和讨论了光声理论及其在内燃机排放中气体浓度和排烟浓度的测量上的应用。     

基于7555定时器的照明光声控制电路

对采用7555定时器为基本元件组成照明光声控制电路进行了研究。这种照明光声控制电路的特点是电路简单,成本低,功耗小。文中介绍了其电路组成,工作原理和参数设计。     

基于激光诊断的生物柴油碳烟生成特性研究

制作了1个以液体为燃料可以产生层流扩散火焰的燃烧器,应用双色激光诱导炽光法(LII)技术来测量火焰中的绝对碳烟体积分数.基于在2个波长上获取的火焰中某1点的LII信号,获得被激光加热的碳烟粒子温度,同时得到此点的碳烟浓度,通过映射得到火焰的二维碳烟浓度分布.采用激光诱导荧光法可获得碳烟前驱物多环芳香烃在火焰中的二维分布,将激光诱导荧光和激光诱导炽光相结合,在柴油和生物柴油混合燃料的层流扩散火焰上进行测试.研究结果表明,随着生物柴油掺混比例的增加,碳烟和多环芳香烃的最大浓度都随之降低,浓区分布面积也进一步缩小.     

氢化微晶硅薄膜制备过程中的氧污染问题

采用光发射谱(OES)测量技术,实时监测了不同本底真空制备条件下氢化微晶硅(μc-SiH)薄膜沉积的氧污染程度.样品的X光电子能谱(XPS)与傅立叶变换红外吸收光谱(FTIR)测量结果表明不同氧污染条件下制备所制备μc-SiH薄膜中,氧以不同的键合模式存在.氧污染程度较低时,氧主要表现为O-O与O-H键合;氧污染严重时,则以Si-O键合占主导.通过Raman光谱、电导率与激活能的测量进一步发现μc-SiH薄膜的结构特性与电学特性随沉积过程中氧污染程度不同发生显著的变化,而且这种变化不同于氧污染对a-SiH薄膜的影响.     

三维瞬变喷雾场浓度与温度分布的激光干涉层析（三）──实验系统及测试结果与分析

为了对柴油机大型喷嘴三维喷束的浓度与温度分布进行测量，本文设计和研制了一套测量与实验系统，并通过选模技术改善了激光光质，从而保证实验顺利进行。利用激光干涉层析术首次对瞬变喷束两油束交叉区的三维浓度与温度分布进行了实际测量，得到较积极的结论。     

并联差分激光光声装置测量柴油机排放碳粒浓度

叙述了并联左分激光江声装置测量柴油机排放碳粒浓度的基本原理和设计考虑。由此建立的装置测量了Ｓ１９５柴油机在不同工况下排放碳粒的浓度，并和Ｂｏｓｃｈ烟度设计的测量结果作出了比较。     

烟颗粒光散射Muller矩阵测量与尺寸、形状参数的研究

对烟颗粒光散射Muller矩阵及其测量原理、测量方法进行了说明,并对依据此测量方法建立的烟颗粒光散射实验平台进行了介绍.根据烟颗粒形状具有分形结构,以及该类颗粒光散射的特点,提出了用光散射Muller矩阵测量烟颗粒回转半径与分形维数的方法,并利用该方法对棉绳阴燃烟颗粒的同转半径进行了测量,结果表明棉绳阴燃烟颗粒的回转半径大致在200-300 nm.     

长测距三维激光扫描仪在露天矿山测量中的应用

利用长距离三维激光扫描仪进行露天矿山测量可以实现不可估量的测量成效.通过分析长距离三维激光扫描仪在露天矿山测量原理,以某矿山工程为例,利用三维激光扫描仪对矿山测量中的数据采集、处理、对比进行系统化分析,总结了三维激光扫描仪开展露天测量的优势及注意事项.     

一种利用太阳能的激光供能方法

设计了一种太阳能光伏发电-激光供能系统,讨论了系统中能量转换效率和供能损耗问题。实验采用人工太阳模拟发射器,通过光伏发电给半导体激光器提供能量发射红外激光,采用透镜准直后照射到光电池上转换成电能。测量了各装置的输入输出功率,计算了能量转换装置的转换效率和传输过程中的能量损耗,提出了改进系统的有效途径。     

基于热红联用分析的木质素热裂解动力学研究

利用热重红外联用系统对生物质的主要组分木质素进行了热裂解动力学研究.在用红外固体压片法研究木质素结构的基础上得到不同升温速率下木质素热裂解的热重曲线.实验结果表明,随着升温速率的增加,各个阶段的起始和终止温度向高温侧轻微移动,主反应区间增加;计算得到的木质素两阶段活化能分别为58.41 kJ/mol和119.98 kJ/mol.与纤维素热解气的联机红外分析谱图相比可知木质素热解过程中气体析出机理复杂,主要生成CO、CH4和呋喃等产物.     

Thin film photodetectors grown epitaxially on silicon

Epitaxial germanium films of thickness d≈4 μm, grown on silicon (001) by a low-temperature MBE process, constituted the base material of a silicon-integrated infrared detector. Characterization of the fully relaxed films was performed mainly by ex situ techniques, such as X-ray diffraction, Rutherford backscattering spectrometry and channeling, room temperature Hall effect and defect etching. Mesa diodes, fabricated from the originally p-type Ge films after pn-junction formation by thermal diffusion of antimony (Sb), showed quantum yields above 40% at wavelengths between 1200 nm and 1500 nm without an antireflection coating. The rise time of the photodiode signal in response to a picosecond laser pulse (τ = 300 ps) at wavelength of 1300 nm was 530 ps. Forward current-voltage characteristics of the devices were described by an ideality factor n = 1.25, while excess current under reverse bias was attributed to leakage caused by threading dislocations in the active layers.     

Effect of laser radiation upon heat and mass transfer in two-component elastic semitransparent layer

In present paper the effect of the correlation between spectral radiative characteristics of different lasers and absorptive characteristics of laser irradiated two-component elastic semitransparent material upon coupled thermal, diffusive and elastic processes in the layer is examined. Irradiated material is supposed to consist of elastic matrix and gaseous admixture. Investigations are carried out within the model applied early to the study of mentioned coupled processes in the layer subjected to thermal infrared radiation. Calculations were carried out for four different infrared lasers. Peculiarities of heat and admixture mass transfer caused by laser irradiation are established and discussed.     

Diode laser sensor for process control and environmental monitoring

Absorption spectroscopy with tunable diode lasers (TDLAS) in the infrared region is a well-known technique for the chemical analysis of gas mixtures. The laser provides a high selectivity, which is important in industrial environments such as in-line stack monitoring, where complex gas mixtures are present. A wavelength tunable diode laser in the near infrared region has been utilized as a light source in absorption measurements of air pollution resulting from energy usage for industry. The emission frequency can be varied over a relatively wide spectral range by changing the current and temperature of the diode.     

Hydrogen production by laser irradiation of metals in water under an ultrasonic field: A novel approach

An alternative method for hydrogen production by laser irradiation of metals in water is proposed. Metals such as Ti, Al, Mg an Al–Mg alloy and Si, were laser ablated and subjected to an ultrasonic field simultaneously to promote a displacement chemical reaction of hydrogen from water. The produced gas was characterized by gas chromatography and mass spectrometry. Molecular hydrogen was found suggesting that this procedure allows the production of H₂ of high purity. All the studied metals under laser irradiation produced H₂ and the volume rise as the laser fluence was increased following a no-linear monotonic behavior with a similar tendency. Without ultrasound the amount of hydrogen was significantly reduced. An important advantage of the proposed H₂ production method is the low amount of mass consumed which lead to maximum hydrogen production rates close to 1300 ml/min per gr of aluminum.     

Nanocrystalline silicon thin films deposited by high-frequency sputtering at low temperature

Intrinsic and n-type hydrogenated nanocrystalline silicon thin films (nc-Si:H) were deposited at a temperature as low as 95 °C by high-frequency (HF) sputtering, with hydrogen dilution percentage varying from 31% to 73%. In order to study the properties of the films prepared by this method, the samples were examined by infrared absorption spectroscopy (IR), X-ray diffraction (XRD), SEM, spectroscopic ellipsometry (SE), laser Raman spectrometry and atomic force microscopy (AFM). XRD measurements showed that this film has a new microstructure, which is different from the films deposited by other methods. In addition, an n-type nc-Si:H/p-type c-Si heterojunction solar cell, which has an open circuit voltage (V_oc) of 370 MV and a short-circuit current intensity (J_sc) of 6.5 mA/cm², was produced on the nanocrystalline silicon thin film. After 10 h light exposure under AM1.5 (100 MW/cm²) light intensity at room temperature, radiation degradation has not been found for the device.     

基于SVM的激光诱导荧光遥感识别海面溢油

随着海洋资源的开发和利用,石油污染变得尤为严重.激光荧光航空遥感对于探测海面、陆地及海滩溢油,是最重要和最有效的技术手段.激光荧光航空遥感监测系统软件部分尤其是涉及到计算机智能信息处理的算法方面有待加强.国内和国外的一些方法在不同程度上取得了成功,而利用支持向量机才刚刚开始.本文主要介绍利用支持向量机算法识别溢油,以光谱形状作为识别的关键特征.测试实验得出,SVM激光荧光光谱分析识别模型的平均训练时间0.0184s,正确率为96.7%.结果表明,SVM激光荧光光谱分析识别模型的绩效是最好的.它是一种很有前途的方法.     

Analysis of bio-oil physicochemical properties and aging process

The physicochemical properties of bio-oil obtained from pyrolysis of rape straw were studied. Main components of bio-oil were qualitatively analyzed by gas chromatography-mass spectrometry and Fourier-transform infrared spectroscopy. It was found that the main components of bio-oil were alcohols, aldehydes, phenols, esters, ketones, and acids. Two-stage condensation device was adopted to enhance the output of bio-oil to 43.53%. The storage and aging process of bio-oil was observed. Viscosity-temperature curve of aging bio-oil was fitted by Matlab programming. Change regulation of chemical compounds and functional groups before and after aging process were analyzed.     

Preparation and characterization of bio-oil by microwave pyrolysis of biomass

A low temperature method was used to produce bio-oil from fir sawdust by means of microwave pyrolysis. Effects of reaction temperature, ratios of the microwave absorption medium to sawdust, and reaction time on the yield of bio-oil were investigated. The results show that an optimized yield of 21.22% is achieved. Bio-oil obtained was analyzed by gas chromatography-mass spectrometry and Fourier transform infrared, and the result reveals that the product mainly consists of phenolic compounds with esteric compounds as the minor components. Thermal weight loss curves of bio-oil were determined by thermogravimetry-differential thermal analysis in the oxygen atmosphere at different super-heating rates, and combustion kinetic parameters were calculated.