Abstract: Provided are a recombinant strain with modified gene BBD29_14900, and a method for constructing the same and use thereof, with the production of L-glutamic acid as a specific application. Further provided is a method for introducing a point mutation into the BBD29_14900 gene coding sequence in Corynebacterium or improving the expression thereof. The method can cause a bacterial strain with the mutation to increase the fermentation yield of glutamic acid. The point mutation involves a mutation of the base at position 1114 in the sequence of the BBD29_14900 gene from guanine (G) to adenine (A), and thus a substitution of aspartic acid at position 372 in the coded corresponding amino acid sequence with asparagine.

Abstract: Disclosed are strain having enhanced L-glutamic acid production capacity, and method for constructing the same and use thereof. A nucleotide sequence is provided by introducing a point mutation to a wild-type BBD29-00405 gene in Corynebacterium glutamicum so that the base at position 597 of SEQ ID NO: 1 is mutated from guanine (G) into adenine (A). Also provided is a recombinant strain obtained by introducing the polynucleotide sequence into L-glutamic acid-producing Corynebacterium glutamicum, the recombinant strain comprising a BBD29-00405 gene containing a point mutation. Compared with an unmodified strain, the resulting strain facilitates production of L-glutamic acid at a higher concentration.

Abstract: A recombinant strain with modified gene BBD29_11265 and a method for constructing the same are provided. The recombinant strain is a bacterium that generates L-glutamic acid, and has an improved expression of a polynucleotide encoding an amino acid sequence of SEQ ID NO: 3 or a homologous sequence thereof; the improved expression can be having a point mutation in, and an enhanced expression of the polynucleotide encoding an amino acid sequence of SEQ ID NO: 3 or a homologous sequence thereof. A genetically engineered bacterium in which the base at position 70 in the BBD29_112665 gene sequence is mutated to adenine from guanine, causing alanine at position 24 in the coded corresponding amino acid sequence to be substituted with threonine, and an engineered bacterium overexpressing the BBD29_112665 gene or BBD29_11265G70A gene are constructed in the present invention, facilitating an increase in the production and conversion rate of L-glutamic acid.

Abstract: The present invention relates to a method of measuring optical fiber link chromatic dispersion by fractional Fourier transformation (FRFT), belonging to the technical field of optical communication. The method of the present invention performs coherent demodulation for an optical pulse signal output from the optical fiber link to obtain a complex field of the optical pulse signal, then performs FRFT on the complex field; according to the energy focusing effect of the chirp signal in the fractional spectrum, calculates an optimal fractional order of the FRFT, and then calculates chromatic dispersion of the optical fiber link according to the optimal fractional order. The method can be applied to an optical fiber communication system consisting of different types of optical fibers, to perform monitoring of optical fiber link chromatic dispersion.

Abstract: The present invention proposes a method for monitoring the nonlinear effect of an optical fiber link by fractional Fourier transformation, FRFT, by calculating an optimal fractional order of the FRFT of the frequency-domain signal propagating through an optical fiber link, calculating the chromatic dispersion of an optical fiber link based on the optimal fractional order, compensating for chromatic dispersion to the signal, calculating an optimal fractional order of the FRFT for the time-domain signal following the compensation for chromatic dispersion, calculating the time-domain chirp caused by the nonlinear effect of an optical fiber link based on the optimal fractional order, and monitoring the nonlinear effect of an optical fiber link based on the absolute value of the calculated time-domain chirp. The method can be used for quantitatively monitoring the nonlinear effect of an optical fiber link in an optical fiber communication system consisting of different types of optical fibers.

Abstract: The present invention proposes a method for monitoring the nonlinear effect of an optical fiber link by fractional Fourier transformation, FRFT, by calculating an optimal fractional order of the FRFT of the frequency-domain signal propagating through an optical fiber link, calculating the chromatic dispersion of an optical fiber link based on the optimal fractional order, compensating for chromatic dispersion to the signal, calculating an optimal fractional order of the FRFT for the time-domain signal following the compensation for chromatic dispersion, calculating the time-domain chirp caused by the nonlinear effect of an optical fiber link based on the optimal fractional order, and monitoring the nonlinear effect of an optical fiber link based on the absolute value of the calculated time-domain chirp. The method can be used for quantitatively monitoring the nonlinear effect of an optical fiber link in an optical fiber communication system consisting of different types of optical fibers.

Abstract: The present invention relates to a method of measuring optical fiber link chromatic dispersion by fractional Fourier transformation (FRFT), belonging to the technical field of optical communication. The method of the present invention performs coherent demodulation for an optical pulse signal output from the optical fiber link to obtain a complex field of the optical pulse signal, then performs FRFT on the complex field; according to the energy focusing effect of the chirp signal in the fractional spectrum, calculates an optimal fractional order of the FRFT, and then calculates chromatic dispersion of the optical fiber link according to the optimal fractional order. The method can be applied to an optical fiber communication system consisting of different types of optical fibers, to perform monitoring of optical fiber link chromatic dispersion.