The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated. The completely autotrophic nitrogen removal over nitrite (CANON) reactor was fed with different con...The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated. The completely autotrophic nitrogen removal over nitrite (CANON) reactor was fed with different concentrations of ammonia (400, 300, and 200 mg N/L) but constant influent ammonia load. The results showed that the CANON system can achieve good treatment performance at ambient temperature (15-23℃). The average removal rate and removal loading of NH4+-N and TN was 83.90%, 1.26 kg N/(m3.day), and 70.14%, 1.09 kg N/(m3.day), respectively. Among the influencing factors like pH, dissolved oxygen and alkalinity, it was indicated that the pH was the key parameter of the performance of the CANON system. Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way. Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria, which had low diversity in different stages, while the species of anaerobic ammonium oxidizing (anammox) bacteria were fewer and the community composition was relatively stable. These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation, which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions.展开更多
An opposite-chirped frequency-domain optical parametric amplification(OC-FOPA) design is demonstrated and numerically verified. This scheme combines both an ultrabroad seeding generation and the subsequent effective a...An opposite-chirped frequency-domain optical parametric amplification(OC-FOPA) design is demonstrated and numerically verified. This scheme combines both an ultrabroad seeding generation and the subsequent effective amplification in one single optical parametric amplification stage. Based on a slightly asymmetrical 4-f optical system, the spectral contents of both pump and signal waves are spectrally dispersed with opposite spatial chirps,to broaden the initial idler seeding. Via a properly designed fan-out periodically poled LiNbO_3 chip, nearly perfect quasi phase matching can be realized across the full spectrum, whereby each individual spectral pair precisely maps to its required grating period. Full-dimensional simulations based on commercial ~110 fs(FWHM) nearinfrared(near-IR) lasers at 790 and 1030 nm are quantitatively discussed, and few-cycle mid-IR laser pulses(~60 fs at 3.4 μm) plus a high conversion efficiency exceeding 50% are theoretically predicted. By means of a high-power pump source, the OC-FOPA scheme can be also applied to directly produce high-intensity carrier-envelope-phase-stabilized mid-IR idler pulses.展开更多
基金supported by the Trans-Century Training Program Foundation for Talents from the Ministry of Education of China (No. NCET-10-0008)the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology (No.QAK201005)the National Water Pollution Control and Management Technology Major Projects (No.2012ZX07202-005)
文摘The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated. The completely autotrophic nitrogen removal over nitrite (CANON) reactor was fed with different concentrations of ammonia (400, 300, and 200 mg N/L) but constant influent ammonia load. The results showed that the CANON system can achieve good treatment performance at ambient temperature (15-23℃). The average removal rate and removal loading of NH4+-N and TN was 83.90%, 1.26 kg N/(m3.day), and 70.14%, 1.09 kg N/(m3.day), respectively. Among the influencing factors like pH, dissolved oxygen and alkalinity, it was indicated that the pH was the key parameter of the performance of the CANON system. Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way. Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria, which had low diversity in different stages, while the species of anaerobic ammonium oxidizing (anammox) bacteria were fewer and the community composition was relatively stable. These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation, which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions.
基金National Natural Science Foundation of China(NSFC)(61505113)Natural Science Foundation of Guangxi Province(2014A030310009)+3 种基金China Postdoctoral Science Foundation(2016M592527)Science and Technology Project of Shenzhen(JCYJ20160308091733202)Science and Technology Planning Project of Guangdong(2016B050501005)Educational Commission of Guangdong Province(2016KCXTD006)
文摘An opposite-chirped frequency-domain optical parametric amplification(OC-FOPA) design is demonstrated and numerically verified. This scheme combines both an ultrabroad seeding generation and the subsequent effective amplification in one single optical parametric amplification stage. Based on a slightly asymmetrical 4-f optical system, the spectral contents of both pump and signal waves are spectrally dispersed with opposite spatial chirps,to broaden the initial idler seeding. Via a properly designed fan-out periodically poled LiNbO_3 chip, nearly perfect quasi phase matching can be realized across the full spectrum, whereby each individual spectral pair precisely maps to its required grating period. Full-dimensional simulations based on commercial ~110 fs(FWHM) nearinfrared(near-IR) lasers at 790 and 1030 nm are quantitatively discussed, and few-cycle mid-IR laser pulses(~60 fs at 3.4 μm) plus a high conversion efficiency exceeding 50% are theoretically predicted. By means of a high-power pump source, the OC-FOPA scheme can be also applied to directly produce high-intensity carrier-envelope-phase-stabilized mid-IR idler pulses.