Dataset Information

Off-Axis Cavity-Enhanced Absorption Spectroscopy of ¹⁴NH₃ in Air Using a Gain-Switched Frequency Comb at 1.514 ?m.

ABSTRACT: A custom-designed gain-switched frequency comb (GSFC) source was passively coupled to a medium finesse (F ? 522) cavity in off-axis configuration for the detection of ammonia (¹⁴NH₃) in static dry air. The absorption of ammonia was detected in the near infrared spectral region between 6604 and 6607 cm^-1 using a Fourier transform detection scheme. More than 30 lines of the GSFC output (free spectral range 2.5 GHz) overlapped with the strongest ro-vibrational ammonia absorption features in that spectral region. With the cavity in off-axis configuration, an NH₃ detection limit of ?3.7 ppmv in 20 s was accomplished in a laboratory environment. The experimental performance of the prototype spectrometer was characterized; advantages, drawbacks and the potential for future applications are discussed.

SUBMITTER: Chandran S

PROVIDER: S-EPMC6928754 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Publications

Off-Axis Cavity-Enhanced Absorption Spectroscopy of 14NH3 in Air Using a Gain-Switched Frequency Comb at 1.514 μm.

Chandran Satheesh S Ruth Albert A AA Martin Eamonn P EP Alexander Justin K JK Peters Frank H FH Anandarajah Prince M PM

Sensors (Basel, Switzerland) 20191128 23

A custom-designed gain-switched frequency comb (GSFC) source was passively coupled to a medium finesse (F ≈ 522) cavity in off-axis configuration for the detection of ammonia (14NH3) in static dry air. The absorption of ammonia was detected in the near infrared spectral region between 6604 and 6607 cm-1 using a Fourier transform detection scheme. More than 30 lines of the GSFC output (free spectral range 2.5 GHz) overlapped with the strongest ro-vibrationa ...[more]

PMID: 31795087

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Project description:BackgroundIn northwest of China, mini Chinese cabbage (Brassica pekinensis) is highly valued by consumers, and is widely cultivated during winter in solar-greenhouses where low light (LL) fluence (between 85 and 150 μmol m-2 s-1 in day) is a major abiotic stress factor limiting plant growth and crop productivity. The mechanisms with which various NH4+: NO3- ratios affected growth and photosynthesis of mini Chinese cabbage under normal (200 μmol m-2 s-1) and low (100 μmol m-2 s-1) light conditions was investigated. The four solutions with different ratios of NH4+: NO3- applied were 0:100, 10:90, 15:85 and 25:75 with the set up in a glasshouse in hydroponic culture. The most appropriate NH4+: NO3- ratio that improved the tolerance of mini Chinese cabbage seedlings to LL was found in our current study.ResultsUnder low light, the application of NH4+: NO3- (10:90) significantly stimulated growth compared to only NO3- by increasing leaf area, canopy spread, biomass accumulation, and net photosynthetic rate. The increase in net photosynthetic rate was associated with an increase in: 1) maximum and effective quantum yield of PSII; 2) activities of Calvin cycle enzymes; and 3) levels of mRNA relative expression of several genes involved in Calvin cycle. In addition, glucose, fructose, sucrose, starch and total carbohydrate, which are the products of CO2 assimilation, accumulated most in the cabbage leaves that were supplied with NH4+: NO3- (10:90) under LL condition. Low light reduced the carbohydrate: nitrogen (C: N) ratio while the application of NH4+: NO3- (10:90) alleviated the negative effect of LL on C: N ratio mainly by increasing total carbohydrate contents.ConclusionsThe application of NH4+:NO3- (10:90) increased rbcL, rbcS, FBA, FBPase and TK expression and/or activities, enhanced photosynthesis, carbohydrate accumulation and improved the tolerance of mini Chinese cabbage seedlings to LL. The results of this study would provide theoretical basis and technical guidance for mini Chinese cabbage production. In practical production, the ratio of NH4+:NO3- should be adjusted with respect to light fluence for successful growing of mini Chinese cabbage.

Dataset Information

Off-Axis Cavity-Enhanced Absorption Spectroscopy of ¹⁴NH₃ in Air Using a Gain-Switched Frequency Comb at 1.514 ?m.

Publications

Off-Axis Cavity-Enhanced Absorption Spectroscopy of <sup>14</sup>NH<sub>3</sub> in Air Using a Gain-Switched Frequency Comb at 1.514 μm.

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OmicsDI is part of the ELIXIR infrastructure

Dataset Information

Off-Axis Cavity-Enhanced Absorption Spectroscopy of 14NH3 in Air Using a Gain-Switched Frequency Comb at 1.514 ?m.

Publications

Off-Axis Cavity-Enhanced Absorption Spectroscopy of <sup>14</sup>NH<sub>3</sub> in Air Using a Gain-Switched Frequency Comb at 1.514 μm.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Off-Axis Cavity-Enhanced Absorption Spectroscopy of ¹⁴NH₃ in Air Using a Gain-Switched Frequency Comb at 1.514 ?m.