基于多光谱法的激发温度和辐射温度瞬态测试技术

近些年来,随着国内外尖端科技快速发展,温度测量无论是对于国防建设领域还是对于工业制造领域都有着极为重要的指导意义和研究价值。尤其在瞬态超高温测量方面,测温精度要求更为严苛。测温方法多种多样,多光谱法由于其精度较高且适用性强,被国内外专家广泛运用。基于多光谱测温法,提出一种新的能够同时高精度测量目标的瞬态激发温度和辐射温度的方法。该方法通过查找可信度更高的目标物理特性数据以及更为精确的多光谱直线拟合方法,精准计算得到目标激发温度。通过建立更加准确的数学模型和算法,减小光谱发射率对整个测温过程的影响实现高精度的辐射温度测量。通过相关测温实验表明,系统测温精度达到3%。     

基于光谱发射率函数基形式不变的辐射测温技术

近年来,随着国防、工业、科技等领域飞速发展,无论是对于军用动力发射系统还是对于民用钢铁冶炼以及高科技新兴产业,辐射温度测量都具有重要意义。尤其在温度极高且伴随着瞬态测温(小于1 μs)需求的场合,多光谱辐射测温法被广泛运用。多光谱辐射测温法是通过选取被测目标多个特征波长,测量特征波长的辐射信息,再假设发射率与波长相关的数学模型,最终求解得到辐射温度。目前,利用该方法实际测温时,光谱发射率都采用固定的假设数学模型,而针对目标在不同温度状态下,该固定模型则无法进行自适应变化。同样,在不同温度下,如何解算最终的发射率和辐射温度也没有普适性的方法。基于普朗克黑体辐射定律,提出一种被测目标在不同温度下光谱发射率函数基形式不变的思想,简称发射率函数基形式不变法。通过该方法,发射率模型可以根据物体在不同温度状态下,函数系数动态改变来进行自适应变化。同时对于如何解算最终的发射率和辐射温度也相应提出了普适性的方法。通过大量仿真验证以及实际测量光谱辐射照度标准灯和溴钨灯温度实验,证明本文提出的方法比现有的光谱发射率处理方法更加简单实用并且能够有效地提高光谱发射率的计算精度,从而提高辐射温度测量精度。同时具有实用性好、应用广泛等特点。     

Magnetic rotation imaging method to measure the geomagnetic field

A new imaging method for measuring the geomagnetic field based on the magnetic rotation effect is put forward. With the help of polarization property of the sunlight reflected from the ground and the magnetic rotation of the atmosphere, the geomagnetic field can be measured by an optical system installed on a satellite. According to its principle, the three-dimensional image of the geomagnetic field can be obtained. The measuring speed of this method is very high, and there is no blind spot and distortion. In this paper, the principle of this method is presented, and some key problems are discussed.     

Measurement network for urban noise assessment: Comparison of mobile measurements and spatial interpolation approaches

This paper investigates the relevance of different interpolation techniques to improve the spatial resolution of urban noise maps, in complement to measurements achieved at fixed stations. Interpolation techniques based on mobile measurements are compared to usual spatial interpolations techniques, namely Inverse Distance Weighting and Kriging. The analyses rely on a measurement campaign, which consisted of nearly 8 h of geo-referenced mobile noise measurements performed at random moments of the day, conducted simultaneously with continuous measurements collected at five fixed stations located on the inner city of Gent, Belgium.Firstly, a procedure is proposed to build a noise map with a high spatial resolution (one point every 5 m). The procedure relies on both mobile and fixed measurements: the mobile measurements are used to capture spatial variations on the network, and the measurements at fixed stations are used to capture the temporal variations. The map produced is then used as reference to compare the interpolation techniques based on a significantly more sparse measurement set.The spatial interpolation techniques tested fail in predicting accurately the noise level variations within streets. The explanation given is that they do not offer a sufficient covering of the network, and assume spatial variations which are not coherent with traffic dynamics or street configurations. Inversely, mobile measurements cover the entire network. As a result, they allow a more accurate prediction of noise levels even if very short samples are used, provided that the procedure used to estimate noise levels includes a spatial aggregation, which aims at smoothing the high spatial variations inevitable with short samples. Moreover, mobile measurements can advantageously be used to optimize, through a Genetic Algorithm, the locations where to install fixed stations, promising an efficient noise monitoring at reduced operational costs.     

Object location fire precision test technology by using intersecting photoelectric detection target

To improve four across screens system measurement precision on flying projectile location, the new method that adds two incline screens to four intersecting screens system to form six intersecting screens was put forward and the flying object coordinate test model was set up. This method not only gains object coordinate but also measures object's pitching and azimuth angle that can amend coordinates and improve measurement precision. The differential methods were used to analyze their measure errors, which came from the angle of intersection screen, the thick of screen, the time and distance of measuring, and give out measure errors distributing. The experimental result shows the new measure method can improve measurement precision that meets test demand.     

量块中心长度测量结果不确定度的评定

测量结果不确定度主要反映量值的可疑程度,只有量值而没有不确定度的数据不是完整的测量结果。文章结合量块检定工作实际,以准确度等级为4等的量块中心长度测量为例,按照JJG146-2003《量块检定规程》进行测量,并依据JJF1059-2007《测量不确定度评定与表示》要求,阐述了量块中心长度测量结果不确定度的评定方法。     

飞参数据测量误差浅析

介绍了测量误差的定义与分类,并对飞参数据测量误差源进行了系统的分析、归纳和总结,为飞参数据的预处理研究提供了理论依据,对于飞参数据的应用研究也具有重要意义。     

碳氢扩散火焰实验研究：燃烧气氛对火焰光谱与温度的影响

辐射是各种燃烧过程中热传递的主要方式。在不同的火焰中,辐射光谱分布十分复杂。在这项工作中,利用光谱仪测量了可见光(200～900 nm),近红外(900～1 700 nm)和中红外(2 500～5 000 nm)波段火焰的光谱强度,分析了空气和富氧气氛下扩散火焰的光谱特征。并基于光谱分析,定量得到了火焰中碳烟以及气体发射的辐射力,计算了火焰的温度分布。结果表明,空气燃烧中的火焰温度低于富氧燃烧中的火焰温度。在空气气氛下,火焰中的碳烟和气体均对中的热辐射起着重要作用。而在富氧气氛下,气体对于火焰热辐射更为重要。在可见光和近红外波段,由于在空气气氛下火焰中碳烟的大量形成,光谱曲线显示出了良好连续性。而富氧气氛下火焰的辐射光谱降低。在中红外波段,空气气氛下火焰的气体辐射明显弱于富氧气氛下火焰的气体辐射。     

基于DIS系统测定自制音叉振动频率的研究

利用自制装置将音叉的振动转换为感应电流,使用数字信息化系统(DIS)微电流传感器,变更测量参量,从而测定出待测音叉的频率.     

A note on a Wiener process with measurement error

In this paper we give a closed form for the determinant and the inverse matrix of the covariance matrix of a Wiener process with measurement error. We will discuss its application in the analysis of degradation data for highly-reliable products.