用于傅里叶变换红外光谱学的光电探测器

Vigo系统公司推出一种型号为PCI-2TE-13的、适用于傅里叶变换红外光谱学的光电探测器。这种探测器的响应光谱带宽为1μm～13μm，具有一个较宽的谱线输出范围。一个内在的两级珀尔帖制冷器使探测器的工作温度保持在220K～240K的范围。探测器的光谱特性是可以改变的，标准的探测器被装在特制的、配有氟化钡窗口的TO-8封壳中，但作为选择，用户也可获得其它式样的封壳、窗口和连接器以及独立的前置放大器／电源、集成的前置放大器／电源／制冷器和热电制冷器的一个控制器。

开放式长光程傅里叶变换红外光谱系统在环境气体分析中的应用

设计了一套用于环境气体分析的长开放光路傅里叶变换红外光谱系统。该系统具有往返250 m的开放式长距离采样光程,使用一台分辨率为1 cm-1的傅里叶变换红外光谱仪测量采样路径内的大气透过率光谱,然后进行非线性最小二乘光谱拟合,计算出待测组分浓度。实验部分通过选择特定波段分析了污染空气中CH4,CO,N2O和CO2的浓度,拟合残差的均方根误差小于1%。结果表明,该系统的结构简单,光路易于校准,环境适应性良好,测量速度快,采样范围广,可用于探测大气中一些重要的痕量和微量组分,开展较大区域的环境气体的监测和研究。

用于傅里叶变换红外光谱学的光电探测器

Vigo系统公司推出一种型号为PCI-2TE-13的、适用于傅里叶变换红外光谱学的光电探测器。这种探测器的响应光谱带宽为1μm～13μm，具有一个较宽的谱线输出范围，一个内在的两级珀尔贴制冷器使探测器的工作温度保持在220K-240K的范围。

新书快讯:《傅里叶变换红外光谱分析》(第2版)简介

由北京大学翁诗甫教授级高工编著的《傅里叶变换红外光谱分析》（第2版）一书已于2010年5月由化学工业出版社出版。本书系统地介绍了红外光谱的基本概念、傅里叶变换红外光谱学的基本原理。

新书快讯:《傅里叶变换红外光谱分析》(第2版)简介

由北京大学翁诗甫教授级高工编著的《傅里叶变换红外光谱分析》（第2版）一书已于2010年5月由化学工业出版社出版。本书系统地介绍了红外光谱的基本概念、傅里叶变换红外光谱学的基本原理、傅里叶变换红外光谱仪的结构、傅里叶变换红外光谱仪附件原理和使用技术、红外光谱样品制备和测试技术、红外光谱数据处理技术、红外光谱的定量分析和未知物的剖析、基团的振动频率分析以及红外光谱仪的保养和维护技术。

大气痕量气体测量的光谱学和化学技术

简略评论了大气痕量气体测量的光谱学和化学技术。光谱技术方面重点介绍差分光学吸收光谱(DOAS)、差分吸收激光雷达(DIAL)、傅里叶变换红外光谱学(FTIR)和可调谐半导体激光吸收光谱(TD-LAS),化学测量技术介绍色谱、质谱和色-质联用技术、化学发光测量技术、基体分离和电子自旋共振技术以及超声膨胀技术等,并对宽带光谱测量、光谱技术之间、光谱技术与化学技术之间的联用趋势,以及仪器的小型化趋势作了展望。

应用光谱重建理论的傅里叶变换光谱仪

本文将重建光谱仪的光谱重建理论应用于傅里叶变换光谱仪中,使光谱仪可以兼具重建光谱仪高光谱分辨率优势以及傅里叶变换光谱仪固有的高光通量优势。利用构建的简易空间外差傅里叶变换光谱仪实验装置在520~530 nm光谱范围内进行验证实验。使用实验装置采集的不同单波长入射光光斑图像进行光谱校准实验,证明了傅里叶变换光谱仪可满足光谱重建理论必需的光斑与波长间唯一的一对一映射关系。随后,使用用于光谱校准的光斑图像进行光谱重建实验,实现了0.10 nm的光谱分辨率,相比通过傅里叶变换光谱仪原理得到的~5.65 nm光谱分辨率有明显提高。最后,使用额外采集的波长525 nm入射光光斑图像进行光谱重建实验,重建光谱中存在重建误差,且525 nm处光谱信号峰的半峰全宽(FWHM)~0.30 nm。光斑图像相关性分析显示,光谱重建受光斑图像采集过程中噪声和相邻波长入射光光斑图像高相似性的影响。尽管如此,重建光谱仍然可以反映入射光的光谱信息,且信号峰的FWHM小于傅里叶变换光谱仪原理得到的光谱,验证了将光谱重建理论应用于傅里叶变换光谱仪的可行性和高光谱分辨率优势。

基于偏振干涉成像光谱仪的视场增强和相位热漂移补偿关键技术的研究

偏振干涉成像光谱技术以傅里叶变换光谱学为理论基础,以一系列起偏/检骗器、剪切分束器和延时晶体等双折射晶体材料为主要结构,较之传统光栅式色散型光谱仪具有多通道、图谱合一、大光通量、高信噪比和抗环境振动干扰等一系列优点,并且结合多普勒光谱学相关原理和技术,已被广泛应用在各种天文学和天体物理学测试与计量领域如空间遥感、视向速度、宇航飞行、月球探测等。但是许多前人研究工作中仍然存在两个尚未妥善解决的问题:(1)视场受限。普通型偏振干涉成像光谱仪存在远场条纹的弯曲而使系统视场角限制在±2°以内,严重影响傅里叶变换后的光谱重构精度;(2)相位热漂移。晶体的热胀冷缩和双折射率之差随温度变化的特性导致像面干涉条纹发生随机抖动误差,将严重影响以多普勒频移为原理的视向速度等测量精度。因此,首先引入一块半波片构成增强型的Savart剪切分束器实现主动的视场展宽,可以使增强后的观察视场角达到±10°左右。这一改进不仅提高了傅里叶光谱变换的算法精度,同时也大幅增加光通量从而实现对微光光谱进行高信噪比的探测与标定。另外,为了消除环境温度造成的相位热漂移误差,选用偏硼酸钡(α-BBO)和铌酸锂(LiNbO3)两种晶体进行精密组合匹配。该关键技术利用这两种晶体的双折射率之差随温度变化的相反特性,从而实现相位热漂移误差补偿。实验证明,在实验室环境温度下热相位漂移误差不超过0.02rad。通过这些方案改善偏振干涉成像光谱仪的测试精度,拟实现对天文光梳以及其他大型天文光谱仪器快速而精确的标定与测试。

时空调制型干涉成像光谱仪的强光干扰效应仿真研究

干涉成像光谱技术是利用光的干涉原理获取目标光谱信息的一种成像技术。为研究其在强光下的干扰效果和机理,以大孔径静态成像光谱仪为典型对象,开展了相关仿真实验研究。以实际地物的图像和光谱信息为对象,仿真生成了原始干涉成像图案,并模拟830 nm单波长激光和超连续谱激光两种干扰源,分别研究不同辐照强度下的典型干扰效果,分析时假设光谱角大于30°时原始光谱信息丢失。基于本文的仿真模型,得到的相关结果表明,在830 nm的单波长激光干扰情况下,当干扰与目标成像峰值之比大于0.2∶1时原始光谱信息无法正确复原(光谱角大于30°),但模拟加入830 nm滤光片后,干扰效果被有效滤除。在超连续谱激光干扰情况下,不考虑饱和阈值时光谱角数值最终稳定在21°;考虑探测器饱和阈值为目标成像强度峰值3倍时,干扰与目标成像峰值之比大于2.1∶1时,原始光谱信息便无法分辨。该研究可能为同类型光谱仪的激光辐照效应和损伤机理的后续研究,以及光谱成像系统的激光防护和性能优化提供参考。

双光梳光谱学研究进展

双光梳光谱仪具有超高光谱分辨率、超快采样时间的特性,是研究分子吸收光谱的有力工具。文章介绍了双光梳光谱仪的基本原理以及它与传统傅里叶光谱仪的区别,叙述了几种典型的双光梳光谱仪构成及其用于测量分子吸收光谱的实验结果,并对双光梳光谱学做了详细说明。随着中红外光梳和中红外探测器技术的进一步发展,双光梳光谱学将会在大气污染监测、呼吸气体检测等重要的国计民生领域得到越来越广泛的应用。

北京奥运期间石化工业区多组分污染气体的开放光程FTIR监测

利用自行研制的开放光程傅里叶变换红外光谱测量系统于2008奥运期间对北京燕山地区大气中的HCHO,CH_4,CH_3OH,C_2H_6,C_2H_4,C_2H_2和CH_3COCH_3气体进行了连续监测,介绍了系统的组成及光谱数据处理方法,并对浓度测量结果进行了分析。研究结果显示,7月20日限行措施实施后,除C_2H_4外,其他气体日平均浓度均有明显下降,平均幅度约29%,奥运期间平均降幅达34%,受局部气象条件引起的本底浓度暂时性波动影响,监测指标物中,C_2H_4平均浓度分别增加6.09%和19.66%,但其日变化幅度明显下降,表明北京市奥运期间的控制减排措施有效。

广州亚运会期间多组分污染气体的抽取式FTIR监测

利用抽取式傅里叶变换红外光谱(FTIR)测量系统于2010广州亚运会期间对广州白云机场地区大气中的多种污染气体进行了连续监测。介绍了系统组成和光谱定量分析方法,并对浓度结果进行了分析。结果显示,一氧化碳和臭氧小时均值浓度具有日周期变化,虽然在监测期间出现了几个极值,但是仍然达到国家二级标准。乙烯和乙炔小时均值浓度具有同步变化规律,两者应来自同一排放源。在整个亚运会期间所监测的污染物组分中未发生明显超标状况,在此期间采取的减排控制措施是有效的。

远红外探测技术的进展

用分子束外延(MBE)方法生长了Ⅱ-Ⅵ族本征甚长波红外(VLWIR,λc约为20μm～50μm)材料——HgCdTe合金和HgCdTe/CdTe超晶格。用X射线衍射、常规傅里叶变换光谱学、霍尔效应测量技术和透射电子显微技术(TEM)对外延层进行了表征。为了验证这些材料在甚长波红外谱区的适用性,用这些材料制成了光导器件并测得了它们的光谱响应。

保健品合成过程中甘油和甲醇的在线监测

红外光谱分析能够实现化合物合成过程的无损检测,且不需样品预处理。应用FTIR和ATR红外探头进行保健品合成过程中甘油和甲醇的过程监测。PLS建立的甘油和甲醇的预测模型具有良好的预测能力,甘油和甲醇红外模型相关系数分别为0.985、0.998 7,可监测到甘油和甲醇含量随时间的变化趋势。甘油和甲醇分别在其加入反应釜40 h和6 h后耗尽。实验结果表明:红外光谱检测技术能够很好的实现保健品合成过程中甘油和甲醇的过程监测。

In situ studies on ceria promoted cobalt oxide for CO oxidation

In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was prepared by the calcination method and investigated for the CO oxidation. The microstructure and morphology of CeO2-Co3O4 were investigated by the Scanning Electron Microscope, High-resolution transmission electron microscopy, Raman and X-ray photoelectron spectroscopy characterization. The effect of CeO2 doping on Co3O4 for CO oxidation was characterized by in situ X-ray Diffraction (in situ XRD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). In situ XRD was carried out under H2 atmosphere to evaluate the redox property of catalysts. The results indicated that the ceria doping can enhance the reducibility of Co2+ and promote the Co3+-Co2+-Co3+ cycle, owing to the oxygen replenish property of CeO2. Furthermore, adsorbed carbonate species on the surface of CeO2-Co3O4 were investigated by in situ-DRIFTS experiment. It was turned out that carbonate species on ceria promoted cobalt oxide catalysts showed different IR peaks compared with pure cobalt oxide. The carbonate species on ceria promoted catalyst are more active, and similar to free state carbonate species with weak bonding to catalyst surface, which can effectively inhibit catalyst inactivation. This study revealed the mechanism of ceria promoting CO oxidation over cobalt oxide, which will provide theoretical support for the design of efficient CO oxidation catalysts.

In vivo and in situ detection of colorectal cancer using Fourier transform infrared spectroscopy

AIM: Real-time and rapid Identification of the malignant tissue can be performed during or before surgical operation. Here we aimed to detect in vivo and in situ colorectal cancer by using Fourier transform infrared (FTIR) spectroscopy and fiber-optic technology. METHODS: A total of five patients with large intestine cancer were detected in vivo and in situ. Of them, three cases of colon cancer and one case of cecum cancer were detected intraoperatively and in vivo by using a FTIR spectrometer during surgical operation, and one case of rectum cancer was explored non-invasively and in vivo before the surgical operation. Normal and malignant colorectal tissues were detected in vivo and in situ using FTIR spectroscopy on the basis of fundamental studies. RESULTS: There were significant differences between FTIR spectra of normal and malignant colorectal tissues detected in vivo and in situ. Experimental results revealed that the spectral characteristics of normal and malignant tissues found in vivo and in situ were similar to those obtained from in vitro measurement in our previous fundamental research. CONCLUSION: FTIR fiber-optic attenuated total reflectance (ATR) spectroscopy can identify in situ and in vivo colorectal cancer. FTIR spectroscopie method with fiber optics is a non-invasive, rapid, accurate and in vivo cancer detection technique in clinical diagnosis.

Synthesis and properties of UV curable polyurethane acrylates based on two different hydroxyethyl acrylates

Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprolactone modified hydroxyethyl acrylate （PCLA2）. The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy （FT-IR）, IH nuclear magnetic resonance （^H NMR）, gel permeation chromatography （GPC） and differential scanning calorimeter （DSC）, and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis （TGA） and dynamic mechanical analysis （DMA）, respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa.s at 25 ℃, while that of PUCA is： up to 3.980 Pa-s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.

Geochemistry of Kasnau-Matasukh lignites, Nagaur Basin, Rajasthan （India）

The distribution and verticals variation of geochemical components in the Kasnau-Matasukh lignites of Nagaur Basin, Rajasthan, were investigated using microscopy, proximate and ultimate analyses, Rock-Eval Pyrolysis, X-ray diffraction and Fourier Transform Infrared analyses, and major/minor/trace element determination. The relationship of elements with ash content and with macerals have also been discussed. These lignites are stratified, black, dominantly composed of huminite group macerals with subordinated amounts of liptinite and inertinite groups. They are classified as type-III kerogen and are mainly gas prone in nature. The concentration （in vol%） of mineral matter is seen to increase towards upper part of seam and so is the concentration （in wt%） of the volatile matter, elemental carbon and sulphur. The common minerals present in these lignitesare mixed clay layer, chlorite, and quartz as identified by X-ray diffraction study. Compared with world average in brown coal, the bulk concentration of Cu is anomalously high in most of the samples while Cd is 2-3 times high and Zn is high in one band. Based on interrelationship, different pyrite forms are noticed to have different preferential enrichment of various elements. The concentration of disseminated pyrite is more than the other pyrite forms and is followed by discrete pyrite grains and massive pyrite.

Adsorption behavior of heptyl xanthate on surface of ZnO and Cu(Ⅱ) activated ZnO using continuous online in situ ATR-FTIR technology

A continuous online in situ attenuated total reflection Fourier-transform infrared(ATR-FTIR)spectroscopic technique was used to investigate the adsorption and desorption kinetics of heptyl xanthate(KHX)on the surface of ZnO and Cu(Ⅱ)activated ZnO.The results showed that Cu(Ⅱ)facilitated the xanthate adsorption process on the surface,and led to the formation of cuprous xanthate(CuX),dixanthogen(X_(2))and xanthate aggregates.The adsorption of xanthate on the surface of ZnO and Cu(Ⅱ)activated ZnO was found to both follow the pseudo-first-order kinetic model.When the NaOH solution was used as a desorption agent,the adsorbed xanthate can largely be removed due to the competition between OH^(−)and HX−.However,for Cu(Ⅱ)activated ZnO,the peak intensities at 1197 and 1082 cm^(−1) had no obvious weakening,and the absorption intensities at 1261 and 1026 cm^(−1) increased in the first 5 min,indicating an ion-exchange reaction between OH^(−)and surface zinc bonded xanthate HX−and the reorganization of adsorbed xanthate.

Growth Kinetics of Silicon Carbide Film Prepared by Heating Polystyrene/Si（111）

SiC films were prepared by heating polystyrene/Si（111） in normal pressure argon atmosphere at different temperatures. The films were investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared absorption measurements. The thicknesses of SiC films were calculated from FTIR spectra. The growth kinetics of the growth process of SiC films were investigated as well. The thicknesses of the SiC films grown for 1 h with increasing growth temperatures have different trends in the three temperature ranges： increasing slowly （1200-1250 ℃）, increasing quickly （1250- 12.70 ℃）, and decreasing （1270-1300 ℃）. The apparent activation energies of the growth process of SiC films in the three ranges were calculated to be 122.5,522.5, and -127.5 J/mol respectively. Mechanisms of the different growth processes were discussed. The relation between film thicknesses and growth temperatures indicated that the growth process was a 2D mechanism in the first range and 3D mechanism in the second range. In the third range, the thicknesses of SiC films were decreased by the volatility of Si and C atoms.