Determination of the coupling length in directional couplers from spectral response

1990 ◽  
Vol 2 (11) ◽  
pp. 823-825 ◽  
Author(s):  
H.C. Cheng ◽  
R.V. Ramaswamy
Keyword(s):  
Spectral Response ◽  
Coupling Length ◽  
Directional Couplers

scholarly journals The spectral response of a phosphor to infra-red radiation

1949 ◽  
Vol 196 (1047) ◽  
pp. 554-562 ◽  
Keyword(s):  
Room Temperature ◽  
Spectral Response ◽  
Cadmium Sulphide ◽  
Air Temperatures ◽  
Infra Red ◽  
Zinc Cadmium ◽  
Temperature Radiation ◽  
First Time ◽  
Red Radiation

A determination of the infra-red spectral response of a copper-activated zinc cadmium sulphide phosphor at normal and at liquid air temperatures is described. Peaks in sensitivity at wave-lengths of 2·1 and 2·7 μ are observed directly for the first time and are correlated with glow-curve data. The incidence of room temperature radiation on a phosphor at liquid air temperature is shown to make the observation of sensitivity beyond 3 μ impracticable.

A New Portable Colorimetric Sensor Based on RGB Chromaticity for Quantitative Determination of Sarin in Water

2020 ◽  
Vol 16 (4) ◽  
pp. 475-484
Author(s):  
Tingting Huang ◽  
Guohong Liu ◽  
Jingxiang Yu ◽  
Meng Liu ◽  
Zhiping Huang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Quantitative Determination ◽  
Light Source ◽  
Potable Water ◽  
Spectral Response ◽  
Water Sources ◽  
Test Tube ◽  
Colorimetric Sensor ◽  
Digital Data

Background: Sarin is a nerve agent which is lethal to people due to its high toxicity. According to its extreme toxicity, sarin, relatively lack of color, highly toxic, miscible in water, poses viable threats to potable water sources. Therefore, there is an urgent need for portable, rapid and yet reliable methods to monitor for adulteration of potable water sources by sarin on spot. Methods: A stock solution of 30 mg/L sarin was prepared daily by dissolving 300 μg of sarin in 10 mL isopropanol. A certain amount of sarin was added to the glass tube, and then o-dianisidine and hydrogen peroxide were added. The pH value of the solution was adjusted to 9.8. The solution was transferred to the test tube after 10 minutes. A test tube of 2 mL was placed between the light source and the RGB color sensor. The LED light source illuminates directly over the test tube while the RGB sensor obtained the generated spectral response. This RGB voltage output is connected to the ADC and microcontroller to convert these analog voltages to three digital data. This RGB digital data is linked to the microcomputer through the serial port that is interfaced with the user interface. The data thus obtained in the sensor can be processed to display the sarin concentration. Results: Under the optimum conditions as described above, the calibration curve of chromaticity value versus sarin concentration was linear in the range of 0.15 mg/L to 7.8 mg/L. According to the IUPAC definition, theoretical detection limits of this method were 0.147 mg/L and 0.140 mg/L for R and B values, respectively. The practical detection limit was 0.15 mg/L. The sensor was successfully applied to the determination of sarin in artificial water samples and the recoveries were between 86.0% to 95.9%. Conclusion: The results in the present work have demonstrated the feasibility to design a new portable colorimetric sensor based on the RGB chromaticity method for quantitative determination of sarin in water. The influences of chromogenic reagent, oxidant, reaction time, o-dianisidine concentration, hydrogen peroxide concentration, reaction temperature, pH on the chromaticity values were investigated. The results showed that the sensor possessed high selectivity, sensitivity and good repeatability. The method would be potentially applied to the analysis of other toxic compounds in environment, such as other chemical warfare agents.

FT-IR Partial Least-Squares Analysis of Tubular Halloysite in Kaolin Samples from the Mount Hope Kaolin Deposit

Clay Minerals ◽  
1993 ◽  
Vol 28 (3) ◽  
pp. 365-378 ◽  
Author(s):  
L J. Janik ◽  
J. L. Keeling
Keyword(s):  
Spectral Response ◽  
South Australia ◽  
Analytical Techniques ◽  
Drill Hole ◽  
Scanning Electron Micrographs ◽  
Partial Least Squares Analysis ◽  
Alternative Approach ◽  
Ft Ir ◽  
Kaolin Deposit

AbstractA method of infrared (IR) analysis for quantitative determination of tubular halloysite in mixtures with kaolinite was investigated for drill hole samples collected during an assessment of paper-coating kaolin resources at the Mount Hope Kaolin Deposit, Eyre Peninsula, South Australia. Tubular, dehydrated halloysite from the deposit does not readily intercalate formamide, and the proportion of tubes in <2 μm size-fractions was determined initially from scanning electron micrographs. For samples showing a range of tube contents, a strong correlation between IR spectral response and counts of halloysite tubes was established using partial leastsquares analysis. This provided a rapid technique suitable for routine determination of tubular halloysite in samples from the Mount Hope deposit. Although the universality of the method remains to be tested, it offers an alternative approach to other analytical techniques for assessment of kaolin deposits where the presence of halloysite is suspected.

scholarly journals Determination of the TROPOMI-SWIR instrument spectral response function

2018 ◽  
Vol 11 (7) ◽  
pp. 3917-3933 ◽  
Author(s):  
Richard M. van Hees ◽  
Paul J. J. Tol ◽  
Sidney Cadot ◽  
Matthijs Krijger ◽  
Stefan T. Persijn ◽  
...  
Keyword(s):  
Response Function ◽  
Near Infrared ◽  
Spectral Response ◽  
Monochromatic Light ◽  
Imaging Spectrometer ◽  
Swir Band ◽  
Shortwave Infrared ◽  
Single Instrument

Abstract. The Tropospheric Monitoring Instrument (TROPOMI) is the single instrument on board the ESA Copernicus Sentinel-5 Precursor satellite. TROPOMI is a nadir-viewing imaging spectrometer with bands in the ultraviolet and visible, the near infrared and the shortwave infrared (SWIR). An accurate instrument spectral response function (ISRF) is required in the SWIR band where absorption lines of CO, methane and water vapor overlap. In this paper, we report on the determination of the TROPOMI-SWIR ISRF during an extensive on-ground calibration campaign. Measurements are taken with a monochromatic light source scanning the whole detector, using the spectrometer itself to determine the light intensity and wavelength. The accuracy of the resulting ISRF calibration key data is well within the requirement for trace-gas retrievals. Long-term in-flight monitoring of SWIR ISRF is achieved using five on-board diode lasers.

Second Derivative Spectrophotometric Determination of Acetaminophen and Phenacetin in Presence of Their Degradation Products

1986 ◽  
Vol 69 (4) ◽  
pp. 608-611
Author(s):  
Mohamed A Korany ◽  
Mona Bedair ◽  
Hoda Mahgoub ◽  
Mahmoud A Elsayed
Keyword(s):  
Spectrophotometric Determination ◽  
Degradation Products ◽  
Spectral Response ◽  
Accurate Method ◽  
Second Derivative ◽  
The Mean ◽  
The Stability

Abstract A rapid and accurate method for determining acetaminophen and phenacetin in presence of their degradation products is presented. Solutions of these drugs in 0.1N HC1 were analyzed by measuring their second derivative spectral response at 295 nm where the degradation products do not interfere. The mean percent recoveries for mixtures of acetaminophen and/or phenacetin with the corresponding degradation products were 100.2 ± 0.6 and 100.6 ± 1.1, respectively. The method can be used for assessing the stability of the 2 drugs. The proposed method is also applied to the determination of acetaminophen in tablets and syrups.

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