Mid-infrared Optical Frequency Comb-based Fourier Transform Spectrometer for Broadband Molecular Spectroscopy

Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of precision spectroscopy and trace gas detection.Here,we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell.Using this instrument,the broadband absorption spectra of several important molecules,including methane,acetylene,water molecules and nitrous oxide,are measured by near real-time data acquisition in the 2800-3500 cm^(-1)spectral region.The achieved minimum detectable absorption of the instrument is 4.4×10^(-8)cm^(-1)·Hz^(-1/2)per spectral element.Broadband spectra of H_(2)0 are fited using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%.Our system also enables precise spectroscopic measurements,and it allows the determination of the spectral line positions and upper state constants of N_(2)O in the(0002)-(1000)band,with results in good agreement with those reported by Toth[Appl.Opt.30,5289(1991)].

Moisture content in raw rubber sheet analyzed by transflectance near infrared spectroscppy

Moisture content is an important trait for rubber sheet trading system.Therefore,a calibrationequation for predicting moisture content was created by near infrared(NIR)technique in order todevelop a more fair trading system in Thailand.Spectra were recorded in two systems.One wasmeasurement on each rubber sheet and the other was on a pile of sheets.Both were[measured by ahandheld NIR spectrometer in the short wavelength region(700-1100 nm)in the transflectancemode using Teflon as a diffuse refector.The spectra showed the peak at about 900 nm whichbelongs to isoprene,the major component of rubber sheet.Pretreatment with second derivativewas applied to remove baseline shift effect occurring due to thickness differences on each rubber sheet.From validation results,moisture contents predicted by single sheet system were moreaccurate than a pile of sheet system with standard error of prediction(SEP)=0.39 %and bias of-0.07%,and they were not significantly diferent from the actual values at 95%confidence.As aresult,determining moisture content in each rubber sheet by a handheld NIR,spectrometerprovided accurate values,easy and rapid operation.

Kinetics of Thermal Decomposition of Lithium Hexafluorophosphate

With on-line coupled thermo-gravimetric technique, the thermal decomposition of analyzer-Fourier transform infrared spectrometer lithium hexafluorophosphate （LiPF6） and its gas evolution at inert environment （H2O〈10 ppm） were studied under both non-isothermal and isothermal conditions. The results showed that the LiPF6 decomposition is a single-stage reaction with LiF as final residue and PF5 as gas product. In addition, its decomposi- tion kinetics was determined as 2D phase boundary movement （cylindrical symmetry） under both non-isothermal and isothermal conditions. Furthermore, the activation energy of LiPF6 decomposition was calculated as 104 and 92 kJ/mol for non-isothermal and isothermal con- ditions, respectively.

Characterization of Pyrolytic Lignin Extracted from Bio-oil

Bio-oil is a new liquid fuel produced by fast pyrolysis,which is a promising technology to convert bio-mass into liquid. Pyrolytic lignin extracted from bio-oil,a fine powder,contributes to the instability of bio-oil. The paper presents the structural features of three kinds of pyrolytic lignin extracted from bio-oil with different methods(WIF,HMM,and LMM) . The pyrolytic lignin samples are characterized by Fourier transform infrared spectrometer(FTIR) and X-ray photoelectron spectroscopy(XPS) . FTIR data indicate that the three pyrolytic lignin samples have similar functional groups,while the absorption intensity is different,and show characteristic vibra-tions of typical lignocellulosic material groups O H(3340-3380 cm-1) ,C H(2912-2929 cm-1) and C O(1652-1725 cm-1) . Comparison in the region(3340-3380 cm-1) indicates that WIF has more O H stretch groups than HMM and LMM. The carbon spectra are fitted to four peaks:C1,C C or C H,BE 283.5 eV;C2,C OR or C OH,BE 284.5-285.8 eV;C3,C O or HO C OR,BE 286.10-287.10 eV;C4,O C O,BE 287.5-287.7 eV. The absence of C1,C C or C H indicates the dominant polymerization structure of aro-matic carbon in pyrolytic lignin samples. For HMM and WIF,C2a and C2b can not be separated,so there is no free hydroxyl group in the samples. The oxygen peaks are also fitted to four peaks:O1,OH,BE = 530.3 eV;O2,RC O,BE 531.45-531.72 eV;O3,O C O,BE = 532.73-533.74 eV;O4,H2O,BE 535 eV. The absence of O1 and O4 indicates that little hydroxyl groups and adsorbed water are present in the samples.

Progress on CASEarth Satellite Development

CASEarth satellite is the first space Earth science satellite produced by the Chinese Academy of Sciences.The satellite has three payloads:high-definition Thermal Infrared Spectrometer(TIS),highdefinition Glimmer Imager for Urbanization(GIU),and high-definition Multispectral Imager for Inshore(MII).These payloads are used to explore the urbanization level and residential layout,the coastal ecosystem,and new methods and approaches of environmental detection during night-time and even under conditions of polar aurora and provide scientific evidence for the refined depiction of human traces.The CASEarth satellite can provide space observation data for A Project on Big Earth Data Science Engineering as well as scientific and application studies inside and outside China.

Characterization of products from photooxidation of toluene

Photooxidation reaction of toluene in smog chamber systems was initiated by the UV radiation of tolucne/CH5ONO/NOx mixtures. The products of the photooxidation reaction of toluene and its subsequent reactions were analyzed directly utilizing Fourier transform infrared spectrometer （FTIR）. Detailed assignments to FTIR spectrum of gas-phase products were given. The information of some important functional groups in the products, such as, carbonyl groups （C-O）, hydroxyl groups （-OH）, carboxylic acid （- COOH）, C-C bonding, N O bonding and C-H bonding （C H）, was got from this analysis. These results were compared to those analyzed by aerosol time of flight mass spectrometer （ATOFMS）. It was found that there are some differcnccs between FTIR analysis of gas-phase products and that of particle-phase, for example, the products with carbonyl groups, which were connected to unsaturated chemical bonds, was relatively higher in the gas phase, while kctoncs, aldehydes, carboxylic acid and organonitrates were the dominant functional groups in the aerosol-phase reaction products. The possible reaction pathways of some important products in the gas phase were also discussed.

印度洋深海热液区贻贝足丝结构和性能特征研究

贻贝营半固着生活,依靠足丝将自己牢固地黏附在底物上。足丝的结构和性能对贻贝的正常生命活动至关重要。为研究热液区极端环境下深海贻贝足丝的结构和性能,采集了印度洋龙旂深海热液区的贻贝(Bathymodiolus marisindicus)足丝,对其力学特性、结构特征和组分进行了分析。力学性能测试发现与近海贻贝(Mytilus galloprovincialis)相比,B.marisindicus足丝的力学性能表现为模量小、弹性小、弹性缓冲较差。傅里叶变换红外光谱(Fourier Transform infrared spectrometer,FT-IR)分析显示深海热液区贻贝足丝的主要成分是胶原蛋白,官能团特征显示足丝蛋白含大量的β折叠结构,足丝近端和远端的二级结构梯度较小。扫描电镜(scanning electron microscope,SEM)结果显示热液区贻贝足丝表面光滑,内部结构呈纤维状整齐排列。氨基酸分析结果显示深海热液区贻贝足丝中甘氨酸、脯氨酸含量高于近海贻贝足丝,这可能会增加足丝蛋白中三螺旋结构的稳定性,使足丝在热液环境中保持性能稳定。热液区深海贻贝足丝独特的力学性能、结构特征和组分特征为研究热液区贻贝的环境适应性提供了一定的基础。

Determination of Shallow Impurity Concentration in Detector-grade Silicon by FT-IR Spectroscopy at 4.2K

A Nicolet-200SXV FT-IR spectrometer combined with an exciting light set-up has been applied to determine the shallow impurity concentration in detector-grade silicon. The detection sensitivity of boron concentration is high up to 7.8 × 10-12. The calibration curve of boron concentration in high-purity silicon has been obtained, from which the experimental value of calibration factor of boron concentration in silicon is demonstrated to be 1.15 × 1013 cm-1.

MEASUREMENT OF CARBON MONOXIDE COLUMN CONTENT AND OTHER ATMOSPHERIC TRACE GASES FROM INFRARED SPECTRA

The measurement of column content of carbon monoxide,methane,and other atmospheric traces gases as well as aerosols has been conducted during the fall of 1992 and 1997,using an infrared spectrometer of moderate resolution in the cooperation of the Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO),Institute of Atmospheric Physics, Chinese Academy of Sciences,with the Institute of Atmospheric Physics,Russian Academy of Sciences.The variation characteristics of atmospheric CO column content in Beijing area are presented.The analysis of the measurement shows that the CO column concentration of 0.10 mg cm^(-2)can be considered as the background over Beijing area.and the concentration as high as 0.75 mg cm^(-2)was observed under some unfavorable meteorological situations.

Constructing zwitterionic nanofiber film for anti-adhesion of marine corrosive microorganisms

A zwitterionic nanofiber film was constructed through combining zwitterionic polymer with anodic aluminum oxide template for anti-adhering typical marine corrosive microorganisms,i.e.Pseudomonas aeruginosa,Desulfovibrio vulgaris and Chaetoceros muelleri.Results showed that the fabricated zwitterionic polymers film has fibrous nanostructure with uniform distribution and super hydrophilia.This film has wide anti-adhering properties,and it can effectively reduce the attachment of these three microorganisms by more than 99%.Moreover,the adhesion of extracellular polymeric substances secreted from these three microorganisms are also inhibited,which is one reason for the fabricated nanofiber film with antiadhesion characteristic of microorganisms.This research provides valuable information for solving the problem of microbial adhesion on metal surfaces in the marine environment.

Processing of Calamine with Modern Analytical Techniques:Processed with Huanglian Decoction(黄连汤)and Sanhuang Decoction(三黄汤)

Objective： To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis products dried at different heating temperatures and explore the critical temperature and the optimal drying temperature for the process of calamine with Huanglian Decoction（HLD, 黄连汤） and San Huang Decoction（SHD, 三黄汤）. Methods： Pyrolysis products were prepared by programmable and constantly heating the calcined and processed calamine to or at different heating temperatures. Thermogravimetry（TG） was used to test their pyrolysis characteristics. Fourier transform infrared spectroscopy and scanning electron microscopeenergy dispersive spectrometer were used to determine their morphology, functional groups and element contents. Page model was used to investigate the constant drying kinetics of processed calamine. Results： The adding of HLD or SHD to calcined calamine（CC） can slow its weight loss in drying pyrolysis process. The temperature ranges where HLD and SHD can affect its weight loss were 65–150 ℃ and 74–180 ℃, respectively. The drying temperature was optimized as 90 ℃. The drying kinetic for the processed calamine fits Page model shows good linearity. Conclusions： The critical temperature and the optimal drying temperature where HLD and SHD can affect the weight loss rate in the process of calamine were explored using the theories and methods of both biophysical chemistry and processing of Chinese materia medica. This work provides a good example for the study of the process of other Chinese medicines using modern analytical techniques.