准确可靠的标定 新的标定方法保证准确的检查结果

在线检测技术，例如采用IR红外线光谱检测技术对流程生产中介质的浓度或者质量进行实时检测时所采用的技术，同时也在流程生产过程中使用的检测技术，通常都属于在线检测技术。本文介绍的新的检测仪器设备标定方法在在线检测中遇到的问题较少，而且可以避免二次校正。[编者按]     

激光光谱吸收技术在天然气气质分析中的应用

在线气质分析仪在天然气行业应用广泛,从气田采气集输到天然气净化处理,再到净化天然气输送等多个生产领域。在线气质分析仪的应用有助于安全生产、提高生产效率;有助于实现节能减排、环境保护等目标;也是检测产品天然气合格与否的重要手段。通过对激光光谱吸收技术的原理介绍,探讨、比较了激光光谱吸收技术和其它检测技术分析仪在天然气领域应用的优缺点,分析了激光光谱吸收技术气体分析仪在天然气领域的应用前景。     

原油含水率的红外光谱快速检测技术

该文旨在探索一种基于红外光谱技术的原油含水率快速检测方法,研究采用油田提供的3种MDT取样流体原油样本,每种原油制备5种含水率、5种矿化度,共计75个不同属性的油水乳状液。采集75个配制样本的红外光谱,进行波长筛选并用"一阶导数+减去一条直线+SG卷积平滑(17)"法对光谱进行预处理,对谱图进行分析,并用偏最小二乘法建立关于原油含水率的定量检测模型。最终建模相关系数R达到94.44%,交互验证均方根误差RMSECV为4.11,相对分析误差RPD为3.04;预测相关系数R为83.54%,预测均方根误差RMSEP为7.44,模型稳健性良好。研究表明红外光谱检测技术对于原油含水率检测具有可行性,为光谱技术应用于原油含水率在线检测奠定了基础,可为测井勘探技术提供一种新的途径。     

近红外光谱分析技术在聚乙烯醇分析中的应用

采用近红外光谱分析仪对聚乙烯醇进行扫描,测定其光谱图。然后对光谱图进行分析处理,利用化学计量学软件,建立定性和定量分析模型。用光纤将近红外光谱仪和检测探头连接起来,组成一个在线分析系统,可以实现在线分析。介绍了近红外光谱分析的基本原理和基本过程。     

PECVD设备Leak在线监控系统创建及应用北大核心CSCD

等离子体增强型化学气相沉积法(PECVD)设备具有高真空特点,容易发生漏气(Leak)事故,为预防事故发生,对PECVD腔室构造、成膜原理及过程进行深入分析。从原理上检讨通过光谱分析方法在线监控PECVD工艺腔室Leak的可行性,搭建了腔室在线监控系统。通过光谱条件的调整测试,发现Ar等离子状态下,Leak光谱和正常光谱差异最大化,更有利于Leak光谱检测,成功实现Leak在线检测,在行业内首次实现PECVD真空腔室在线监控功能。     

基于可见/近红外光谱分析技术的水性油墨黏度预测模型

针对水性油墨黏度测量方法存在操作复杂、主观性强等问题,利用可见/近红外光谱分析技术结合化学计量学方法,建立水性油墨黏度预测模型,实现水性油墨黏度的快速无损检测。首先,利用微型光纤光谱仪采集水性油墨样本的反射光谱;再通过比较不同预处理方法对原始光谱数据的预处理效果,分别基于原始全光谱及预处理后的光谱数据构建水性油墨黏度的偏最小二乘回归(PLSR)和主成分回归(PCR)预测模型;最后,将预处理后的光谱数据采用连续投影算法(SPA)和竞争性自适应重加权算法(CARS)提取特征波长,并基于特征波长的光谱数据建立水性油墨黏度的PLS预测回归模型。结果表明,采用SPA算法从全光谱中只提取了4个特征波长,不仅显著简化了模型,提升了模型的运算效率,建立的SNV-SPA-PLS模型还具有最佳的预测性能(R_p²=0.9992,RMSEP=0.0732)。该研究结果表明应用光谱分析技术实现对水性油墨黏度检测是有效可行的,为进一步通过光谱分析技术进行水性油墨在线黏度检测提供了新方法,为提高印刷品质量稳定性提供了技术基础。     

无纺布在线检测中的图象处理技术

本文主要论述了无纺布在线检测中的图象处理技术,并对计算机图像处理技术的在线检测进行了可行性分析和论证,为无纺布在线检测的自动化和可实现性提供了理论依据.这种信息与过程控制的结合是一种开放式的系统技术、也是数据库和系统标准化的发展产物;同时,也阐述了无纺布的结构特性检测方法的发展趋势.     

66千伏及以上电力电缆绝缘在线监测系统研究

交联电缆的使用越来越广泛,对其进行在线检测也日趋重要。本文对电缆绝缘进行在线监测方法做了概括介绍,并介绍了一种在不需改变电力系统的原有接线方式便可实现电力电缆绝缘状态的在线测量技术的研究。     

智能变电站web在线监测技术研究

本文对当前变电站中的检修和检测技术进行分析，探讨了智能变电站的在线检测技术，最后分析在线检测系统中的设备参数。     

实时观察反应过程 利用变角衰减全反射傅立叶变换红外光谱法（ATR-FTIR）对聚缩反应过程进行实时跟踪观察

ReactIR在线红外光谱分析技术允许直接对化学反应过程进行跟踪观察，这种光谱分析技术的基础是一个变角衰减全反射傅立叶变换红外光谱仪。在原位反转录聚合酶链式反应分析技术中，光谱仪经光导折射系统与反应釜中的检测传感器连接在一起。本文介绍了这种技术在聚磺合成过程中定性的和定量分析的应用情况。[编者按]     

Long-path monitoring of NO2 with a 635 nm diode laser using frequency-modulation spectroscopy

In situ monitoring of traffic-generated nitrogen dioxide (NO2) emissions using long-path absorption spectroscopy is reported. High-sensitivity detection of NO2 is achieved by employing two-tone frequency-modulation spectroscopy at a visible absorption band using a tunable high-power diode laser operated around 635 nm. A real-time absorption spectrometer is accomplished by repetitively applying a rectangular current pulse to the diode-laser operating current, allowing detection of isolated NO2 absorption lines. A detection limit of 10 microg/m3 for NO2 at atmospheric pressure using a 160 m absorption path is demonstrated. Continuous monitoring of NO2 over a road intersection at peak traffic is performed.     

Laser-induced fluorescence spectroscopy for phenol and intermediate products in aqueous solutions degraded by pulsed corona discharges above water

Laser-induced fluorescence (LIF) spectroscopy is introduced as an in situ diagnostic for phenol and intermediate products in an aqueous solution degraded by corona discharges. The complications that are inherent in applying LIF as a diagnostic for aqueous solutions are experimentally examined. The LIF intensities of phenol and the intermediate products are measured as a function of time. The absolute phenol concentration is determined. We confirm the applicability of LIF spectroscopy for monitoring phenol concentration during degradation.     

Cure kinetics characterization and monitoring of an epoxy resin using DSC,Raman spectroscopy,and DEA

The use of thick sections of fiber-reinforced polymers (FRPs) is increasing for numerous industrial applications such as wind turbine blades. In situ cure monitoring is very important to directly observe the cure process of FRPs during the manufacturing process. In this work, Raman spectroscopy and dielectric analysis (DEA) are investigated for in situ cure monitoring of an epoxy resin. The cure behavior is first characterized using differential scanning calorimetry (DSC) as a baseline comparison, and the best-fit phenomenological reaction model is determined to describe the cure behavior of the epoxy resin as well as the kinetic parameters. The relationship between T_g and degree of cure is also established. The degree of cure obtained from Raman spectroscopy and DEA under isothermal conditions is compared to that obtained from DSC. A good agreement is observed among the three methods, supporting the potential of these in situ cure monitoring methods during manufacturing. An implementation plan for in-plant monitoring is also discussed.     

Modified coin cells for in situ Raman spectroelectrochemical measurements of Li(x)V2O5 for lithium rechargeable batteries

In situ Raman spectroscopy is an extremely valuable technique for investigating fundamental reactions that occur inside lithium rechargeable batteries. However, specialized in situ Raman spectroelectrochemical cells must be constructed to perform these experiments. These cells are often quite different from the cells used in normal electrochemical investigations. More importantly, the number of cells is usually limited by construction costs; thus, routine usage of in situ Raman spectroscopy is hampered for most laboratories. This paper describes a modification to industrially available coin cells that facilitates routine in situ Raman spectroelectrochemical measurements of lithium batteries. To test this strategy, in situ Raman spectroelectrochemical measurements are performed on Li//V2O5 cells. Various phases of Li(x)V2O5 could be identified in the modified coin cells with Raman spectroscopy, and the electrochemical cycling performance between in situ and unmodified cells is nearly identical.     

Development of a measuring system for on-line in situ monitoring of composite materials manufacturing

A unique portable measuring system using an impedance spectroscopy method with a self-adapting frequency of measurement is introduced. The system is intended for the on-line in situ monitoring of composite materials curing under industrial conditions. The capabilities of the developed system are demonstrated through the results obtained from on-line in situ measurements of unreinforced thermosetting resin, as well as of composites under real manufacturing conditions. Observations are supported by the results of other established methods for determining the degree of curing: temperature-modulated differential scanning calorimetry (MDSC), Fourier transform infrared spectroscopy (FT-IR) and broadband dielectric spectroscopy (BDS). Compressive and bending tests were also carried out on manufactured composites removed at different stages of the post-curing phase. Due to the self-adapting frequency, the system has enhanced sensitivity in the post-cure phase when the diffusion-controlled reactions proceed and, therefore, is suitable also for the analysis of hard post-cure samples.     

Design and application of a new cell for in situ infrared reflection-absorption spectroscopy investigations of metal-atmosphere interfaces

A new experimental setup for studying reactions occurring in the metal-atmosphere interface by applying in situ infrared reflection-absorption spectroscopy (IRRAS) is presented. It consists of a gas-mixing unit, where the moist air is generated with or without corrosive gases, the reaction cell for the in situ investigations, and an optical system coupled with a Fourier transform infrared (FT-IR) spectrometer. For testing the unit, a specimen of pure copper was used, where the growth of Cu2O on the polished surface could be observed during time-resolved measurements in synthetic air containing 80% RH (relative humidity). For comparison of the experimental results obtained, a computer simulation program was developed in order to calculate the peak position, the peak height, the peak width, and the thickness of the surface layer formed during the atmospheric corrosion. The simulation software is based on the four-phase model of covered surfaces.     

Advanced calibration strategy for in situ quantitative monitoring of phase transition processes in suspensions using FT-Raman spectroscopy

There is an increasing interest in using Raman spectroscopy to identify polymorphic forms and monitor phase changes in pharmaceutical products for quality control. Compared with other analytical techniques for the identification of polymorphs such as X-ray powder diffractometry and infrared spectroscopy, FT-Raman spectroscopy has the advantages of enabling fast, in situ, and nondestructive measurements of complex systems such as suspension samples. However, for suspension samples, Raman intensities depend on the analyte concentrations as well as the particle size, overall solid content, and homogeneity of the solid phase in the mixtures, which makes quantitative Raman analysis rather difficult. In this contribution, an advanced model has been derived to explicitly account for the confounding effects of a sample's physical properties on Raman intensities. On the basis of this model, a unique calibration strategy called multiplicative effects correction (MEC) was proposed to separate the Raman contributions due to changes in analyte concentration from those caused by the multiplicative confounding effects of the sample's physical properties. MEC has been applied to predict the anhydrate concentrations from in situ FT-Raman measurements made during the crystallization and phase transition processes of citric acid in water. The experimental results show that MEC can effectively correct for the confounding effects of the particle size and overall solid content of the solid phase on Raman intensities and, therefore, provide much more accurate in situ quantitative predictions of anhydrate concentration during crystallization and phase transition processes than traditional PLS calibration methods.     

Mössbauer study of the nature of differences in the uniaxial magnetic anisotropy of FeAlN and FeTaN films

Thin FeAlN and FeTaN films were deposited by RF magnetron sputtering in an external magnetic field with (i) in situ crystal growth and (ii) ex situ controlled thermal crystallization of amorphous deposit, respectively, and their microstructures were studied using Mössbauer spectroscopy. The films obtained by the two methods possess different uniaxial magnetic anisotropy, which is related to the different microstructures of FeAlN and FeTaN systems and the opposite signs of stresses in the crystal lattices: expansion in FeAlN versus contraction in FeTaN.     

Electrochemical preparation and characterization of thin deposits of Pd-noble metal alloys

The procedures of Pd-noble metal alloy (Pd-Au, Pd-Pt, Pd-Rh, Pd-Pt-Rh) preparation by electrochemical deposition from chloride solutions are described. The influence of deposition conditions on alloy composition is presented. The deposits were characterized electrochemically in acidic solutions (H₂SO₄ aq) by cyclic voltammetry. The surface morphology of the alloys was examined by scanning electron microscopy and scanning tunneling microscopy. The alloy surface composition was investigated in situ by the electrochemical method and ex situ by Auger electron spectroscopy, while the bulk composition was determined by energy dispersive analysis of X-rays and atomic absorption spectroscopy. The electrochemical methods of the real surface area determination were compared and discussed.     

Fiber-optic laser sensor for mine detection and verification

What we believe to be a new optical approach for the identification of mines and explosives by analyzing the surface materials and not only bulk is developed. A conventional manually operated mine prodder is upgraded by laser-induced breakdown spectroscopy (LIBS). In situ and real-time information of materials that are in front of the prodder are obtained during the demining process in order to optimize the security aspects and the speed of demining. A Cr4+:Nd3+:YAG microchip laser is used as a seed laser for an ytterbium-fiber amplifier to generate high-power laser pulses at 1064 nm with pulse powers up to E(p) = 1 mJ, a repetition rate of f(rep.) = 2-20 kHz and a pulse duration of t(p) = 620 ps. The recorded LIBS signals are analyzed by applying neural networks for the data analysis.