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Wide Absorption Spectrum Measuring Methods by DFB-LDs in Water Vapor Detection System 被引量:2
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作者 Y. N. LIU J. CHANG +11 位作者 J. LIAN Q. WANG G. P. LV W. J. WANG Z. LIU X. Z. LIU S. S. ZHANG Z. L. WANG S. JIANG C. G. ZHU W. WEI B.N. SUN 《Photonic Sensors》 SCIE EI CAS 2014年第3期230-235,共6页
Two measuring methods of the wide absorption spectrum by distributed feedback laser diodes (DFB-LDs) are presented in detecting the water vapor absorption line. One is the subsection scanning method, and it takes ad... Two measuring methods of the wide absorption spectrum by distributed feedback laser diodes (DFB-LDs) are presented in detecting the water vapor absorption line. One is the subsection scanning method, and it takes advantage of the wide spectrum tuning range by the temperature modulation and fast spectrum tuning speed by current modulation. Specifically, this method is realized by dividing a target spectral region into several sections which correspond to the specific temperature of DFB-LD, scanning every section by current modulation for hundreds times, and averaging the data to raise the signal to noise ratio (SNR), then combining all sections to get the whole spectrum. An accuracy of 10ppmv had been obtained in the measurement of water vapor with a 10-cm path length by this method. Another is data fitting method, based on the absorption line-shape function; the absorption line can be described by fitting with partial measured data. The fitting absorption line was fitted well with the measured data, and the square of correlation coefficient (R-square) was no less than 0.99. 展开更多
关键词 DFB-LD wide spectrum subsection scanning data fitting water vapor detection
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Polymer-coated symmetrical metal-cladding waveguide for chemical vapor detection with high sensitivity 被引量:1
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作者 XIAO PingPing DENG ManLan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第11期2024-2029,共6页
An optical platform for sensitive detection of chemical vapor based on a polymer-coated symmetrical metal-cladding waveguide is proposed.The diffusion of chemical vapor usually leads to a combinational effect in the p... An optical platform for sensitive detection of chemical vapor based on a polymer-coated symmetrical metal-cladding waveguide is proposed.The diffusion of chemical vapor usually leads to a combinational effect in the polymer layer,i.e.,swelling and refractive index change.Owing to the high sensitivity of ultrahigh-order modes,the vapor-induced effect will give rise to a dramatic variation of the reflected light intensity.For proof-of-concept,a good linearity and a low detection limit of toluene and benzene are experimentally demonstrated with an amorphous Teflon AF polymer layer. 展开更多
关键词 chemical vapor detection polymer layer symmetrical metal-cladding waveguide ultrahigh-order mode
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Rapid Detection of Accelerants in Fire Debris Using a Field Portable Mid-Infrared Quantum Cascade Laser Based Analyzer
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作者 Hao Huang Yongfeng Zhang +6 位作者 Fuqiang Dai Xiaobo Yan Altayeb Hamdalnile Liyun Wu Tingting Zhang Haowen Li Frank Inscore 《Open Journal of Applied Sciences》 CAS 2023年第5期746-757,共12页
Arson presents a challenging crime scene for fire investigators worldwide. Key to the investigation of suspected arson cases is the analysis of fire debris for the presence of accelerants or ignitable liquids. This st... Arson presents a challenging crime scene for fire investigators worldwide. Key to the investigation of suspected arson cases is the analysis of fire debris for the presence of accelerants or ignitable liquids. This study has investigated the application and method development of vapor phase mid-Infrared (mid-IR) spectroscopy using a field portable quantum cascade laser (QCL) based system for the detection and identification of accelerant residues such as gasoline, diesel, and ethanol in fire debris. A searchable spectral library of various ignitable fluids and fuel components measured in the vapor phase was constructed that allowed for real-time identification of accelerants present in samples using software developed in-house. Measurement of vapors collected from paper material that had been doused with an accelerant followed by controlled burning and then extinguished with water showed that positive identification could be achieved for gasoline, diesel, and ethanol. This vapor phase mid-IR QCL method is rapid, easy to use, and has the sensitivity and discrimination capability that make it well suited for non-destructive crime scene sample analysis. Sampling and measurement can be performed in minutes with this 7.5 kg instrument. This vibrational spectroscopic method required no time-consuming sample pretreatment or complicated solvent extraction procedure. The results of this initial feasibility study demonstrate that this portable fire debris analyzer would greatly benefit arson investigators performing analysis on-site. 展开更多
关键词 Quantum Cascade Laser (QCL) Mid-Infrared Spectroscopy Fire Debris Analysis Gasoline vapor detection Ignitable Liquids
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Interaction of straight chain alcohol vapors with self-assembled MOF film by surface plasmon resonance sensing and imaging 被引量:1
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作者 Jun Chen Ji-Ying Xu Yi Chen 《Chinese Chemical Letters》 SCIE CAS CSCD 2013年第7期651-653,共3页
Interaction of straight chain alcohol vapors with MOF-199-functionalized films was studied by SPR. The signals had linear relationships with the concentration of alcohols over a wide range from 0 to 70% (v/v) and we... Interaction of straight chain alcohol vapors with MOF-199-functionalized films was studied by SPR. The signals had linear relationships with the concentration of alcohols over a wide range from 0 to 70% (v/v) and were reversible in proportional to the chain length, with R2 all above 0.99. 展开更多
关键词 Layer by layer self-assemble of MOF Oriented growth Alcohol vapors detection Surface plasmon resonance or SPR
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