We theoretically analyze and experimentally demonstrate a method of generating equal-amplitude optical comb exploiting multi-frequency phase modulation. The theoretical analysis shows that 4n-1 equalamplitude spectral...We theoretically analyze and experimentally demonstrate a method of generating equal-amplitude optical comb exploiting multi-frequency phase modulation. The theoretical analysis shows that 4n-1 equalamplitude spectral lines can be obtained when the modulation signal comprises n frequency components including the fundamental frequency and the odd harmonic frequencies, and 2n＋1 equal-amplitude spectral lines can be obtained when the modulation signal comprises n frequency components including the fundamental frequency and the even harmonic frequencies. Then, we numerically simulate the spectra of 5, 7, 9, and 11 equal-amplitude spectral lines, respectively, which are also obtained in experiments with frequency separation of 30 MHz and flatness of better than 0.3 dB.展开更多
We establish a system to measure the functional absorption cross section of photosystem lI （PSII） （O-PSII） and maximum quantum yield of photochemistry in PSII （Fv/Fm）. The system utilizes a sequence of high-freq...We establish a system to measure the functional absorption cross section of photosystem lI （PSII） （O-PSII） and maximum quantum yield of photochemistry in PSII （Fv/Fm）. The system utilizes a sequence of high-frequency excitation flashes at microsecond intervals to induce a microsecond-level fluorescence yield curve. Parameters o-Psii and Fv/Fm are calculated by fitting the curve using nonlinear regression. Experimental results show that the relative standard deviation （RSD） of the system is less than 3%, and the correlation coefficient of Fv/Fm values measured by this system and those measured by pulse amplitude modulation method is 0.950.展开更多
A novel method of measuring non-uniform strain along a fiber Bragg grating(FBG) using optical frequency domain reflectometry(OFDR) is proposed and experimentally demonstrated. This method can overcome the problems of ...A novel method of measuring non-uniform strain along a fiber Bragg grating(FBG) using optical frequency domain reflectometry(OFDR) is proposed and experimentally demonstrated. This method can overcome the problems of traditional non-uniform strain measurement methods for FBGs, i.e., the likelihood of chirping and multiple peaking in the spectrum when FBG is subjected to inhomogeneous strain fields. Wavelength interrogation is realized by OFDR with a narrow-line-width tunable laser as the optical source. When non-uniform strain distributions along areas adjacent to structural damage are measured by this method, good agreement is obtained between measurements and theoretical simulation results.展开更多
Based on the study of single pattern matching, MBF algorithm is proposed by imitating the string searching procedure of human. The algorithm preprocesses the pattern by using the idea of Quick Search algorithm and the...Based on the study of single pattern matching, MBF algorithm is proposed by imitating the string searching procedure of human. The algorithm preprocesses the pattern by using the idea of Quick Search algorithm and the already-matched pattern psefix and suffix information. In searching phase, the algorithm makes use of the!character using frequency and the continue-skip idea. The experiment shows that MBF algorithm is more efficient than other algorithms.展开更多
基金supported by the China Postdoctoral Science Foundation(No.20060400230)the Foundation for Innovation Talents by the Technology Ministry of Harbin(No.2006RFQXG025)
文摘We theoretically analyze and experimentally demonstrate a method of generating equal-amplitude optical comb exploiting multi-frequency phase modulation. The theoretical analysis shows that 4n-1 equalamplitude spectral lines can be obtained when the modulation signal comprises n frequency components including the fundamental frequency and the odd harmonic frequencies, and 2n＋1 equal-amplitude spectral lines can be obtained when the modulation signal comprises n frequency components including the fundamental frequency and the even harmonic frequencies. Then, we numerically simulate the spectra of 5, 7, 9, and 11 equal-amplitude spectral lines, respectively, which are also obtained in experiments with frequency separation of 30 MHz and flatness of better than 0.3 dB.
基金the Natural Science Foundation of Anhui Province(No.1408085MD72)the National"863"Program of China(Nos.2014AA06A509,2013AA065502,and 2009AA063005)+2 种基金the Science and Technology Planning Project of Anhui Province(No.1206c0805012)the National Natural Science Foundationof China(No.61378041)the Excellent Youth Foundation of Anhui Scientific Committee(No.1108085J19).
文摘We establish a system to measure the functional absorption cross section of photosystem lI （PSII） （O-PSII） and maximum quantum yield of photochemistry in PSII （Fv/Fm）. The system utilizes a sequence of high-frequency excitation flashes at microsecond intervals to induce a microsecond-level fluorescence yield curve. Parameters o-Psii and Fv/Fm are calculated by fitting the curve using nonlinear regression. Experimental results show that the relative standard deviation （RSD） of the system is less than 3%, and the correlation coefficient of Fv/Fm values measured by this system and those measured by pulse amplitude modulation method is 0.950.
基金supported by the National High Technology Research and Development Program of China under Grant No.2012AA041203
文摘A novel method of measuring non-uniform strain along a fiber Bragg grating(FBG) using optical frequency domain reflectometry(OFDR) is proposed and experimentally demonstrated. This method can overcome the problems of traditional non-uniform strain measurement methods for FBGs, i.e., the likelihood of chirping and multiple peaking in the spectrum when FBG is subjected to inhomogeneous strain fields. Wavelength interrogation is realized by OFDR with a narrow-line-width tunable laser as the optical source. When non-uniform strain distributions along areas adjacent to structural damage are measured by this method, good agreement is obtained between measurements and theoretical simulation results.
文摘Based on the study of single pattern matching, MBF algorithm is proposed by imitating the string searching procedure of human. The algorithm preprocesses the pattern by using the idea of Quick Search algorithm and the already-matched pattern psefix and suffix information. In searching phase, the algorithm makes use of the!character using frequency and the continue-skip idea. The experiment shows that MBF algorithm is more efficient than other algorithms.
