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A New Field Tunable Diode Laser Absorption Spectrometer For Highly Sensitive Measurements of Atmospheric Gases 一种用于大气气体高灵敏度测量的新型场可调谐二极管激光吸收光谱仪
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.wb.2
A. Fried, S. Sewell, B. Henry, J. Drummond
{"title":"A New Field Tunable Diode Laser Absorption Spectrometer For Highly Sensitive Measurements of Atmospheric Gases","authors":"A. Fried, S. Sewell, B. Henry, J. Drummond","doi":"10.1364/laca.1994.wb.2","DOIUrl":"https://doi.org/10.1364/laca.1994.wb.2","url":null,"abstract":"The technique of tunable diode laser absorption spectroscopy (TDLAS) has been employed in a number of field investigations for studying the chemistry of both the lower atmosphere (the troposphere) as well as the middle atmosphere (the stratosphere) over the past several years.1 This technique offers many advantages in such studies including: high sensitivity, high selectivity, high precision, fast response, and versatility. The present paper describes a new field TDLAS system, which has been developed at the National Center for Atmospheric Research (NCAR), for furthering our understanding of tropospheric chemistry using this spectroscopic technique. Several novel features have been incorporated in the present system such as a new commercially-available astigmatic Herriott cell and digital signal processing electronics to further improve system performance and versatility. These aspects will be discussed in the present paper along with recent measurements of formaldehyde employing this system at a remote sampling site in Colorado.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124692131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Hook Spectroscopy as a Single-Shot OH Density and Temperature Diagnostic 胡克光谱作为单次氢氧根密度和温度诊断
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.tub.1
D. Zerkle, A. Sappey
{"title":"Hook Spectroscopy as a Single-Shot OH Density and Temperature Diagnostic","authors":"D. Zerkle, A. Sappey","doi":"10.1364/laca.1994.tub.1","DOIUrl":"https://doi.org/10.1364/laca.1994.tub.1","url":null,"abstract":"Hook spectroscopy is being implemented to measure OH density and temperature in a premixed, CH4/air, atmospheric pressure flame on a single shot basis. The hook method makes use of the region of anomalous dispersion surrounding electronic transitions, typically in atomsl. In this region, the refractive index of the sample experiences dramatic shifts from its non-resonant values as shown in Figure 1. As seen in the figure, the solid curve has a minimum on the blue side of λ0, and a maximum to the red. The dashed curve represents the Sellmeier approximation to the refractivity which assumes that the linewidth is infinitely narrow. This approximation is normally quite valid in the wings of electronic transitions and is used to simplify the mathematics involved in determining number density from hook spectra.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131194734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Fluorescence Imaging of Large Molecules in the Gas Phase Generated by Laser Desorption 激光解吸气相大分子的荧光成像
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.ma3
E. Yeung, S. Kimbrell, T. Heise
{"title":"Fluorescence Imaging of Large Molecules in the Gas Phase Generated by Laser Desorption","authors":"E. Yeung, S. Kimbrell, T. Heise","doi":"10.1364/laca.1992.ma3","DOIUrl":"https://doi.org/10.1364/laca.1992.ma3","url":null,"abstract":"Lasers have been used since 1962 to vaporize small amounts of solid inorganic material. More recently their use to vaporize (desorb) large thermally labile organic molecules has grown. The larger and more polar the molecule, the more difficult it is to volatilize it by traditional means without thermal degradation. Very promising is matrix assisted laser desorption, which can produce large gas-phase molecules without fragmentation. Analytical measurements can then be performed on large molecules in the gas phase.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129211050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Atmospheric Multi-Component Pollution Analysis Using CO2 Laser 利用CO2激光分析大气多组分污染
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.wc7
M. Rob, Frank C. Franceschetti
{"title":"Atmospheric Multi-Component Pollution Analysis Using CO2 Laser","authors":"M. Rob, Frank C. Franceschetti","doi":"10.1364/laca.1992.wc7","DOIUrl":"https://doi.org/10.1364/laca.1992.wc7","url":null,"abstract":"The laser spectroscopic techniques for detecting minor gaseous pollutants of the atmosphere have made rapid advances in the last few years. The most important optical process for detection of air pollutants is based on the extinction of radiation by molecular absorption. Each molecule absorbs light at a particular wavelength or a range of wavelengths, a characteristic of the molecule. Thus a measurement of absorption of light at the molecule's characteristic wavelength produces a mean of determining a particular molecule at the presence of other molecules. Problems can, and often arise from overlapping spectrums due to other molecules of the atmosphere. In this case, it is necessary to identify the molecules which cause these overlappings. In some cases, one might be interested in finding multiple pollutants of the atmosphere.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126728597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Laser-Based Spectroscopic Detection of Photolytic Rare Gas Complexes 光解稀有气体配合物的激光光谱检测
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.wc10
G. W. Lemire, M. McQuaid, R. Sausa
{"title":"Laser-Based Spectroscopic Detection of Photolytic Rare Gas Complexes","authors":"G. W. Lemire, M. McQuaid, R. Sausa","doi":"10.1364/laca.1992.wc10","DOIUrl":"https://doi.org/10.1364/laca.1992.wc10","url":null,"abstract":"In recent years there has been a renewed interest in laser-based spectroscopic studies of jet-cooled complexes.1,2 However, much of this work centered on rare-gas (RG) closed shell complexes. We have constructed an apparatus that will allow us to study supersonically cooled photolysis products including rare-gas open shelled complexes. The apparatus consists of a reflectron time-of-flight mass spectrometer with access to LIF diagnostics. As a test case, we have investigated jet-cooled NO-rare gas generated from the supersonic expansion of a NO/Ar mixture and the 193 nm photolysis of NO2/Ar in an extender channel off a pulsed nozzle. The complexes were detected by laser induced fluorescence (LIF) and by (1 + 1) resonance-multiphoton ionization (REMPI) via the A2E+ ← X2Π1/2,3/2 transition near 226 nm.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123362221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Measuring CO Concentration and Temperature in a CH4/air Premixed Flame with Broadband Coherent Anti-Stokes Raman Spectroscopy 用宽带相干反斯托克斯拉曼光谱测量CH4/空气预混火焰中CO浓度和温度
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.wd.6
J. Hahn, S. Park, K. Kang, S. Chung
{"title":"Measuring CO Concentration and Temperature in a CH4/air Premixed Flame with Broadband Coherent Anti-Stokes Raman Spectroscopy","authors":"J. Hahn, S. Park, K. Kang, S. Chung","doi":"10.1364/laca.1994.wd.6","DOIUrl":"https://doi.org/10.1364/laca.1994.wd.6","url":null,"abstract":"Coherent anti-Stokes Raman spectroscopy (CARS) has been widely used as a diagnostic tool for probing the temperature and species concentration of gas phase samples. CARS concentration measurements are typically performed either from the integration1,2 or from the shape of a CARS spectrum.3, 4 If the resonant signal of CARS is much bigger than the nonresonant background, integration of the CARS spectrum depends linearly on the squares of the concentration of the species. In practice, this method can be used to measure the concentration of major species. When the fraction of a species goes down to the order of a few percentage, the nonresonant background becomes comparable to the resonant signal of CARS and interferes with the resonant signal. In such a case, the portion of the nonresonant background included in the integration of the CARS spectrum leads to a large error in the concentration measurement. The interference of the nonresonant background and the real term of the resonant signal of CARS form modulation dips on the spectrum that are sensitive to the concentration. Recently Hahn et al.5 proposed a new technique for measuring the minor species concentration from the modulation dip of nonresonant background of broadband CARS spectrum.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126335619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Dual Fabry-Perot Optical Fiber Sensor 双Fabry-Perot光纤传感器
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.wd.1
Qi Wang
{"title":"A Dual Fabry-Perot Optical Fiber Sensor","authors":"Qi Wang","doi":"10.1364/laca.1994.wd.1","DOIUrl":"https://doi.org/10.1364/laca.1994.wd.1","url":null,"abstract":"Interferometric fiber—optic sensors, while capable of high resolution .have in general been accompanied by a limited unambiguous operating range. They also have had limited applicability for measurement temperature, strain and displacment. Owing to the problem of initiating the system, i. e. the interferometer switch off, all the information about the measured phase will be lost and new initial conditions must be determined when system is turn on again(1). A. S. Gerges had presented a system which is a Michelson interferometer with two equal length arms. A digital feedback servo is used to track the zero optical path difference(2). However, the optical fiber in Gerges’s system are inherently distributed sensors. This can be a disadvantage when point measurment Eire required. G. Beheim had presented another system in which a Fabry-Perot cavity is used as a sensing cavity(3), a Michelson interferometer is used to measure the spacing of the sensing cavity. Let us call it FPM system. The central peak of the interferometric fringe in FPM system is nearly as higher as other peaks. This makes the system very difficult to lock in the central peak. Also, the central peak's half-width of the FPM system is comparatively larger than that of dual F-P system ( DFP ) . This limits the resolution of FPM system. G. Beheim has also presented a dual F-P cavities system. But its electronics CEUI not make sure that the system is locked in the central peak of the transmitted optical signal(4).","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"280 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121255474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Measurements of Rotation and Fluorescence Lifetimes for Optimizing the Detection of Single Fluorescinated Bases 旋转和荧光寿命的测量优化单个荧光碱基的检测
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1990.tha5
L. Davis, N. Seitzinger, E. Shera, R. Keller
{"title":"Measurements of Rotation and Fluorescence Lifetimes for Optimizing the Detection of Single Fluorescinated Bases","authors":"L. Davis, N. Seitzinger, E. Shera, R. Keller","doi":"10.1364/laca.1990.tha5","DOIUrl":"https://doi.org/10.1364/laca.1990.tha5","url":null,"abstract":"Time Correlated Single Photon Counting is an optimum technique for acquiring fluo­rescence decay profiles over a large dynamic range with accurately known errors. The data are fully utilized in a statistical sense when analyzed by weighted non-linear fitting to a decay function convolved with the experimentally measured prompt response function.1","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"94 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122700048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Optical and Laser Diagnostics for Molten Carbonate Fuel Cells 熔融碳酸盐燃料电池的光学和激光诊断
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.tha3
B. Palmer, D. J. Funk, R. Oldenborg
{"title":"Optical and Laser Diagnostics for Molten Carbonate Fuel Cells","authors":"B. Palmer, D. J. Funk, R. Oldenborg","doi":"10.1364/laca.1992.tha3","DOIUrl":"https://doi.org/10.1364/laca.1992.tha3","url":null,"abstract":"Molten-carbonate fuel cells (MCFCs) operate at 650°C and 0.1-1 MPa. MCFCs generate electrical energy through the conversion of the fuel gas (either natural gas or coal gas) using an electrolyte of molten carbonate with nickel electrodes. Because of the heat and the corrosive nature of the carbonate and gases, traditional diagnostics are not applicable. We have developed several diagnostics that can be used in such cells for in-situ measurements. We demonstrated CARS as an in-situ detector for major species, especially CO2, in a MCFC. Measurements of CO2 concentrations over a cell give a spatial measure of the operation and efficiency of the cell. We have also demonstrated laser-induced breakdown spectroscopy and photo-fragment spectroscopy as viable techniques for studying the gaseous alkali halides and alkali hydroxides that form as a result of chlorine contamination in the feed gas. We will also talk about our work on a HC1 monitor for the feed lines.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128076101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Study of the High Temperature Multiplex HCℓ CARS Spectrum 高温复用HC - CARS谱的研究
Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.wc5
W. Kao, J. Singh, F. Yueh, R. Cook
{"title":"Study of the High Temperature Multiplex HCℓ CARS Spectrum","authors":"W. Kao, J. Singh, F. Yueh, R. Cook","doi":"10.1364/laca.1992.wc5","DOIUrl":"https://doi.org/10.1364/laca.1992.wc5","url":null,"abstract":"Coherent Anti-Stokes Raman Spectroscopy (CARS) is a laser based advanced combustion diagnostic technique and is being used to measure the temperature and major species concentration in a turbulent, harsh, high luminescence and reactive combustion environment.1 Recently, it has also been applied to a Coal Fired Flow Facility (CFFF), which is a unique practical combustion environment.2 Only a few CARS applications to chemical reaction have been reported. One of the important chemical reactions is a chlorination reaction. CH4 + Cℓ2 → CH3Cℓ + HCℓ. This is being used to manufacture the halogenated hydrocarbon. HCℓ is one of the product species in the reaction. So, there is a possibility to apply the multiplex HCℓ CARS spectrum for temperature measurements in a chemical reactor. This type of measurement should provide the information about mixing of CH4 and Cℓ2 and also the completion of the reaction.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115190717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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