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: The present disclosure discloses a sound device a frame; a vibration system supported on the frame; a magnetic system with a magnetic gap supported on the frame; the vibration system includes a diaphragm assembly having a diaphragm and a coil inserted in the magnetic gap to drive the diaphragm for sound generation; the diaphragm assembly includes a diaphragm holder fixed to the frame and the diaphragm fixed to the diaphragm holder for sound generation; the diaphragm includes a first flat part having an opening, a folded ring part in the shape of a ring on the outside of the first flat part, and an attachment part on the outside of the folded ring part and fixedly connected to the diaphragm holder; the diaphragm assembly also includes a waterproof breathable film fixed to the first flat part, the first flat part includes a first inner edge away from the folded ring part; observed along the vibration direction, the first inner edge is located on the inner side of the coil, and an outer edge of the waterproof br

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: A dome material, a diaphragm and a speaker are provided. The speaker includes the diaphragm made of the dome material. The dome material includes an intermediate layer, an adhesive layer, a film layer, and a surface layer. The adhesive layer, the film layer, and the surface layer are sequentially stacked on the intermediate layer in a direction away from the intermediate layer. The intermediate layer is formed by a foamed material. A thickness of the adhesive layer is 3-20 ?m. The film layer is adhered to the intermediate layer via the adhesive layer. A thickness of the film layer is 2-20 ?m. The surface layer adopts fiber prepreg including fiber and resin, the fiber is unidirectionally arranged, and a weight percentage of the fiber is 20%-50%. A surface density of the fiber prepreg is 10-100 g/m2.

Abstract: A dome material, a diaphragm and a speaker are provided. The speaker includes the diaphragm made of the dome material. The dome material includes an intermediate layer, an adhesive layer, a film layer, and a surface layer. The adhesive layer, the film layer, and the surface layer are sequentially stacked on the intermediate layer in a direction away from the intermediate layer. The intermediate layer is formed by a foamed material. A thickness of the adhesive layer is 3-20 ?m. The film layer is adhered to the intermediate layer via the adhesive layer. A thickness of the film layer is 2-20 ?m. The surface layer adopts fiber prepreg including fiber and resin, the fiber is unidirectionally arranged, and a weight percentage of the fiber is 20%-50%. A surface density of the fiber prepreg is 10-100 g/m2.

Abstract: The present disclosure disclose a diaphragm dome, the diaphragm dome includes a first carbon fiber layer and a second carbon fiber layer which are alternatively arranged by stacking, the first carbon fiber layer and the second carbon fiber layer are respectively a single-layer structure formed by an one-way extended carbon fiber bundle, an extending direction of the carbon fiber bundle of the first carbon fiber layer is perpendicular to an extending direction of the carbon fiber bundle of the second carbon fiber layer, and a thickness difference exists between the first carbon fiber layer and the second carbon fiber layer. In the diaphragm dome provided by the present disclosure, the material has larger specific strength, thus can reduce the thickness of the diaphragm dome, the carbon fiber layers of the diaphragm dome are well adhered, which is not readily layered, and has good water resistance.

Abstract: The present disclosure disclose a diaphragm dome, the diaphragm dome includes a first carbon fiber layer and a second carbon fiber layer which are alternatively arranged by stacking, the first carbon fiber layer and the second carbon fiber layer are respectively a single-layer structure formed by an one-way extended carbon fiber bundle, an extending direction of the carbon fiber bundle of the first carbon fiber layer is perpendicular to an extending direction of the carbon fiber bundle of the second carbon fiber layer, and a thickness difference exists between the first carbon fiber layer and the second carbon fiber layer. In the diaphragm dome provided by the present disclosure, the material has larger specific strength, thus can reduce the thickness of the diaphragm dome, the carbon fiber layers of the diaphragm dome are well adhered, which is not readily layered, and has good water resistance.