Errors of temperature measurement with multiband infrared systems

A model of the errors of temperature measurement with multiband systems was developed. Calculations of these errors for some measurement conditions and systems were carried out. It was shown that multiband systems are capable of producing accurate results of noncontact temperature measurement only in a limited number of applications and that to have small internal errors, they must be designed and built with much greater care than in the case of typical single-band systems.     

Measure of the influence of detector noise on temperature-measurement accuracy for multiband infrared systems

The noise-equivalent temperature difference is a measure of the detector-noise-limited sensitivity of single-band IR systems for noncontact temperature measurement. However, because its definition is based on the signal-to-noise ratio in a single detector channel, the notion of noise-equivalent temperature difference must be generalized in case of dual-band or multiband IR systems. A new measure of temperature-measurement sensitivity is proposed that can be used to describe single-band, dual-band, and multiband IR measurement systems. With this measure a comparison of temperature-measurement accuracy among single-band, dual-band, and multiband systems was carried out.     

特气红外探测器的温度分析

为了改进特气红外探测器的性能,本文运用热传导理论,分析了在一定功率的单色均匀红外射线激励下的温度变化情况,提出近似模型建立了吸收腔的热传导方程;求解方程得到了吸收腔内各处温度变化和平均温度变化的确切表达式,分析表明特气红外探测器的响应度(气体平均温升决定)与吸收腔的腔深1成线性关系,与特气吸收系数аλ成非线性关系.进而建立了非单色红外射线激励下的热传导方程,提出求解方法.     

Pressure, flow and temperature transients in refrigeration systems

The pressure, flow and temperature transients which occur in simple refrigeration systems (incorporating both dry expansion and flooded evaporators), when subjected to disturbances such as control and load inputs and when defrosting, are described. The effects of oil in such systems are also considered. It is concluded that such transients have a significant influence on system reliability and that system design still contains a significant element of art as well as technology.     

Image fusion methodology for efficient interpretation of multiband images in 3D high‐resolution ultrasonic transmission tomography

With the critical innovations of using submillimeter transducers and multiband analysis of the first arrival pulse, a high‐resolution ultrasonic transmission tomography (HUTT) system has been built and tested to produce multiband images of biological organs at submillimeter resolution. Since the resulting multiband images consist of frequency‐dependent attenuation coefficients (relative to water reference) of transmitted ultrasound pulses, their contrast and sharpness depend on the specific frequency band(s) used for image formation. Even though this multiband representation provides a powerful tool for soft‐tissue differentiation, it hinders visual inspection and limits the visual interpretation of image contents in a short time. To facilitate the visual interpretation of HUTT multiband images, this article presents an efficient image fusion methodology called local principal component analysis with structure tensor (LPCA‐ST). The LPCA has been known as a feasible tool for the fusion of spectral data, since it utilizes the principal components of spectral data as a fusion‐weighting vector of local area. Nonetheless, the LPCA‐fused image often suffers from oversmoothness because of the redundancy of the spectral data. To prevent this problem, we propose a structure tensor as the metric used to select the most informative bands for subsequent LPCA fusion. Our preliminary studies have shown that the contrast of the LPCA‐fused image improves dramatically only when multiband images whose values of the respective structure tensor are the highest are used in the LPCA fusion process. This is achieved in 3D without increasing the computational complexity of the fusion process. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 277–282, 2009     

All-fiber-optic infrared multispectral radiometer for measurements of temperature and emissivity of graybodies at near-room temperature

An all-fiber-optic infrared multispectral radiometer for measurements of temperature and emissivity of graybodies at near-room temperature was constructed. Different spectral regions in the radiometer were obtained by use of hollow glass waveguides (HGWs) as filters. Using HGWs instead of bulk filters was advantageous because each HGW can be used as two different spectral filters when a dual-band IR detector is used. In addition, HGWs are much cheaper than the bulk IR filters that are usually used in such applications. For one graybody with a mean emissivity of 0.71, the estimated mean errors obtained for sample temperature, ambient temperature, and sample emissivity for all measured temperatures were 0.50% (approximately 1.65 K), 0.48% (approximately 1.4 K), and 7.3% (approximately 0.052) respectively. For a second graybody with a mean emissivity of 0.8 the estimated mean errors were 0.35% (approximately 1.2 K), 0.48% (approximately 1.4 K), and 5.0% (approximately 0.04), respectively.     

红外辐射温度计的试验光学系统设计

辐射源尺寸效应(SSE)是辐射测温的重要不确定度来源.为了研究SSE对辐射测温的影响,找出光学系统对克服SSE起到的作用,设计了红外辐射温度计的试验光学系统.光学系统采用透射式外调焦的结构,能够对330mm至无穷远物距的目标源调焦,并根据SSE产生的原因,光学系统结构设置有可调节的孔径光阑和消杂光光阑;同时为了减少光学系统像差对测温的影响,选用红外材料氟化钙(CaF2)和石英玻璃(F_Silica)设计了消像差物镜和二次聚焦的会聚透镜,其点列图弥散斑接近衍射极限,满足试验要求.     

Effect of synthesized temperature on microstructure, infrared emissivity and dielectric property of Fe-doped ZnO powder

Fe-doped ZnO powder has been synthesized by coprecipitation method under different synthesized temperature, using zinc nitrate as the staring material, urea as the precipitator, and ferric nitrate as the doping source, respectively. The prepared powders have been characterized by XRD and SEM. Results show that when the synthesized temperature is below 700 °C the prepared powders are ZnO(Fe) solid solution powders and the ZnFe₂O₄ impurity phase appeared for the Fe-doped ZnO powder synthesized at 700 °C. The electric permittivities in the frequency range of 8.2–12.4 GHz and average infrared emissivity at the waveband range of 8–14 μm of prepared powders have been determined. The real part and imaginary part of electric permittivities of prepared powders have increased firstly and then decreased with increasing synthesized temperature. The average infrared emissivity has presented the opposite changing trend.     

A structured approach to deadlock detection,avoidance and resolution in flexible manufacturing systems

Production scheduling models that determine part mix ratios and detailed schedules do not usually account for deadlocks that can be caused by part flow. Deadlocks must be prevented for operational control (especially in automated systems). The major thrust of this paper is in developing a structured model for deadlock detection, avoidance and resolution caused by part flow in manufacturing systems. A system status graph can be constructed for the parts currently in the system. Deadlock detection amounts to determining deadlocks in the system status graph. On the other hand, deadlock avoidance amounts to restricting parts movement so that deadlocks are completely avoided in the future. While deadlock detection is a one-step look ahead procedure, deadlock avoidance is a complete look ahead procedure. Deadlock resolution or recovery amounts to judiciously using a limited queue to recover from deadlocks. Deadlock detection and avoidance are absolutely crucial to uninterrupted operation of automated manufacturing systems. A model based in graph theory has been formulated to detect and avoid deadlocks in automated manufacturing systems.     

用于人体体温筛查的红外体温计使用和计量要点

0引言近期,新型冠状病毒肺炎疫情严峻,测量体温成为防控疫情的必要手段,而红外体温计等人体测温仪器是疫情防控中用于人体体温筛查的必备医用计量器具。通过近段时间开展的计量校准工作(如图1所示),我们认为疫情防控用体温测量仪器使用和计量工作需要注意以几个方面。     

Background correction and multivariate curve resolution of online liquid chromatography with infrared spectrometric detection

The use of multivariate curve resolution-alternating least-squares (MCR-ALS) in liquid chromatography-infrared detection (LC-IR) is troublesome due to the intense background absorption changes during gradient elution. Its use has been facilitated by previous removal of a significant part of the solvent background IR contributions due to common mobile phase systems employed during reversed phase gradient applications. Two straightforward background correction approaches based on simple-to-use interactive self-modeling mixture analysis (SIMPLISMA) and principal component analysis (PCA) are proposed and evaluated on reversed phase gradient LC-IR data sets obtained during the analysis of carbohydrate and nitrophenol mixtures. After subtraction of the calculated background signal, MCR-ALS provided improved signal-to-noise ratios, removed remaining mobile phase and background signal contributions, and resolved overlapping chromatographic peaks. The present approach tends to enable easy-to-use background correction to facilitate the use of MCR-ALS in online LC-IR, even in challenging situations when gradient conditions are employed and only poor chromatographic resolution is achieved. It, therefore, shows great potential to facilitate the full exploitation of the advantages of simultaneous quantification and identification of a vast amount of analytes employing online IR detection, making new exciting applications more accessible.     

SiO2-Fe2O3-Cr2O3-MnO2高温红外辐射节能涂料的制备及应用

以SiO2、Fe2O3、Cr2O3、MnO2为原料按比例混合,经固相高温烧结制备成基体粉料,再与粘结剂混合球磨制备出高温红外辐射节能涂料。通过XRD、半球点测试仪、红外辐射测量仪、纳米粒度测试仪对材料的微观结构和理化性能进行了表征,采用热震法对涂层的抗热震性能进行了研究。研究结果表明,随着平均粒径的减小,合成的SiO2-Fe2O3-Cr2O3-MnO2体系全波段红外辐射率有明显增大的趋势。当平均粒径达到2μm左右时,涂料全波段红外辐射率最高达到0.93。涂料的最高使用温度达1400℃以上,涂层的抗热震性能良好。此外,在燃气梭式干燥窑上使用该高温红外辐射节能涂料后,降低能耗15%左右,抗老化性能优良,使用一年后辐射率仍在0.90以上。     

Simultaneous determination of mono-, di-, and triglycerides in multiphase systems by online Fourier transform infrared spectroscopy

Glycerides are of significant value for industry as ingredients with different purposes in food or cosmetics. The analysis of glycerides is mainly performed by gas chromatography (GC) or high-pressure liquid chromatography (HPLC), which demonstrate limitations in dealing with multiphase systems. In this article, an in situ differentiation between mono-, di-, and triglycerides in multiphase systems by Fourier transform infrared (FT-IR) spectroscopy is demonstrated. The enzymatic esterification of glycerol with lauric acid was analyzed as a model system. The reaction was carried out in a bubble column reactor containing four phases (two liquid phases of glycerol and lauric acid, air as gaseous phase, and a heterogeneous catalyst as solid phase). As a feasibility study, a chemometric model was generated for the pure components only. The quantities of lauric acid and the three products (mono-, di-, and trilaurin) were simultaneously determined over the course of the reaction with acceptable errors (1.8-12.5%) with regard to the calibration effort. This technology has the potential to give accurate results, particularly in unstable emulsion systems containing fats, oils, or emulsifiers, which are currently afflicted by analytical errors caused by the challenge of accurate sampling.