An optical chemical sensor has been developed for the determination of iodine based on the reversible fluorescence quenching of 2, 2, 7, 7, 12, 12, 17, 17-octamethyl-21, 22, 23, 24-tetraoxaquaterene-Li （LiTOE） imm...An optical chemical sensor has been developed for the determination of iodine based on the reversible fluorescence quenching of 2, 2, 7, 7, 12, 12, 17, 17-octamethyl-21, 22, 23, 24-tetraoxaquaterene-Li （LiTOE） immobilized in a plasticized poly（vinyl chloride） （PVC） membrane. The optimum membrane of the sensor consists of 100 mg of PVC, 200 mg of bis （2-ethytbexyl） sebacate （BOS） and 3.0 mg of LiTOE. The maximum response of the optode membrane for iodine is obtained in Tris-HCl buffer solutlon （pH 8.0）. With the optimum conditions described, the proposed sensor responds linearly in the measuring range of 3.90×10^-2 to 3.90×10^-4 mol/L, and has a detection limit of 6.0×10^-8 mol/L. The response time of the sensor is less than I rain. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity. It is not interfered by some common anions and cations. It is applied for the determination of iodine in table salt samples. The results agree with those obtained by another method.展开更多
A low-cost and portable optical chemical sensor based ammonia sensing system that is capable of detecting dissolved ammonia up to 5 ppm is presented. In the system, an optical chemical sensor is designed and fabricate...A low-cost and portable optical chemical sensor based ammonia sensing system that is capable of detecting dissolved ammonia up to 5 ppm is presented. In the system, an optical chemical sensor is designed and fabricated for sensing dissolved ammonia concentrations. The sensor uses eosin as the fluorescence dye which is immobilized on the glass substrate by a gas-permeable protection layer. A compact module is developed to hold the optical components, and a battery powered micro-controller system is designed to read out and process the data measured. The system operates without the requirement of laboratory instruments that makes it cost effective and highly portable. Moreover, the calculated results in the system can be transmitted to a PC wirelessly, which allows the remote and real-time monitoring of dissolved ammonia.展开更多
Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser （VCSEL） with polarization m...Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser （VCSEL） with polarization maintaining （PM） fiber pigtail is fabricated as a decoy state laser source. The VCSEL is packaged in a standard butterfly box integrated with thermoelectric coder （TEC） and thermistor. The optical pulse width of full-width at half-maximum （FWHM） is smaller than 400 ps with a 100-MHz on/off modulation frequency. The results reveal that modulation range is better than 4. Moreover, the polarization is stable, and the power extinction ratio is larger than 25. The center wavelength is 850 nm, and the SMSR is better than 40 dB.展开更多
文摘An optical chemical sensor has been developed for the determination of iodine based on the reversible fluorescence quenching of 2, 2, 7, 7, 12, 12, 17, 17-octamethyl-21, 22, 23, 24-tetraoxaquaterene-Li （LiTOE） immobilized in a plasticized poly（vinyl chloride） （PVC） membrane. The optimum membrane of the sensor consists of 100 mg of PVC, 200 mg of bis （2-ethytbexyl） sebacate （BOS） and 3.0 mg of LiTOE. The maximum response of the optode membrane for iodine is obtained in Tris-HCl buffer solutlon （pH 8.0）. With the optimum conditions described, the proposed sensor responds linearly in the measuring range of 3.90×10^-2 to 3.90×10^-4 mol/L, and has a detection limit of 6.0×10^-8 mol/L. The response time of the sensor is less than I rain. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity. It is not interfered by some common anions and cations. It is applied for the determination of iodine in table salt samples. The results agree with those obtained by another method.
基金This work was supported by Enterprise Ireland （El） and Science Foundation Ireland （SFI）. The authors would like to thank Pat O＇Leary from Faaltech Technologies Ltd and Jean-Michel Rubillon from Cork Institute of Technology for their support and help.
文摘A low-cost and portable optical chemical sensor based ammonia sensing system that is capable of detecting dissolved ammonia up to 5 ppm is presented. In the system, an optical chemical sensor is designed and fabricated for sensing dissolved ammonia concentrations. The sensor uses eosin as the fluorescence dye which is immobilized on the glass substrate by a gas-permeable protection layer. A compact module is developed to hold the optical components, and a battery powered micro-controller system is designed to read out and process the data measured. The system operates without the requirement of laboratory instruments that makes it cost effective and highly portable. Moreover, the calculated results in the system can be transmitted to a PC wirelessly, which allows the remote and real-time monitoring of dissolved ammonia.
文摘Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser （VCSEL） with polarization maintaining （PM） fiber pigtail is fabricated as a decoy state laser source. The VCSEL is packaged in a standard butterfly box integrated with thermoelectric coder （TEC） and thermistor. The optical pulse width of full-width at half-maximum （FWHM） is smaller than 400 ps with a 100-MHz on/off modulation frequency. The results reveal that modulation range is better than 4. Moreover, the polarization is stable, and the power extinction ratio is larger than 25. The center wavelength is 850 nm, and the SMSR is better than 40 dB.
