Wild relatives and un-adapted germplasm of crop species harbors several adaptive traits.Introgression of genes for economic and adaptive traits brings in novel genetic variation into the gene
Associated dynamic performance of the clamping force control valve used in continuously variable transmission （CVT） is optimized. Firstly, the structure and working principle of the valve are analyzed, and then a dy...Associated dynamic performance of the clamping force control valve used in continuously variable transmission （CVT） is optimized. Firstly, the structure and working principle of the valve are analyzed, and then a dynamic model is set up by means of mechanism analysis. For the purpose of checking the validity of the modeling method, a prototype workpiece of the valve is manufactured for comparison test, and its simulation result follows the experimental result quite well. An associated performance index is founded considering the response time, overshoot and saving energy, and five structural parameters are selected to adjust for deriving the optimal associated performance index. The optimization problem is solved by the genetic algorithm （GA） with necessary constraints. Finally, the properties of the optimized valve are compared with those of the prototype workpiece, and the results prove that the dynamic performance indexes of the optimized valve are much better than those of the prototype workpiece.展开更多
A maize (Zea mays L.) genome_specific repeated DNA sequence (clone MR64) has been transferred into one DH line of wheat through wheat (Triticum persicum Vav. ex Zhuk.) and maize cross. In the present study by RFLP ana...A maize (Zea mays L.) genome_specific repeated DNA sequence (clone MR64) has been transferred into one DH line of wheat through wheat (Triticum persicum Vav. ex Zhuk.) and maize cross. In the present study by RFLP analysis the authors proved that this DNA sequence could stably transmit into DH3 plants, the next generation derived from DH2 self_crossing. A similarity search in all DNA databases using BLASTN program showed that the DNA sequence of MR64 had as high as 93% identity to PREM_2 and 79% to Opie_2 in nucleotides. Both PREM_2 and Opie_2 are known as retrotransposons in maize genome, suggesting that MR64 likely is the partial sequence of a maize retrotransposon. Therefore, the results indicate that some retrotransposon might involve the DNA introgression from maize to wheat genome through wide fertilization. Stable inheritance of this maize genome_specific retrotransposon_like DNA in the wheat genome opens up the possibility of using retrotransposon as a new tool for gene tagging, function analysis, and insertional mutagenesis in wheat genome.展开更多
文摘Wild relatives and un-adapted germplasm of crop species harbors several adaptive traits.Introgression of genes for economic and adaptive traits brings in novel genetic variation into the gene
基金Key Science-Technology Foundation of Hunan Province, China (No. 05GK2007).
文摘Associated dynamic performance of the clamping force control valve used in continuously variable transmission （CVT） is optimized. Firstly, the structure and working principle of the valve are analyzed, and then a dynamic model is set up by means of mechanism analysis. For the purpose of checking the validity of the modeling method, a prototype workpiece of the valve is manufactured for comparison test, and its simulation result follows the experimental result quite well. An associated performance index is founded considering the response time, overshoot and saving energy, and five structural parameters are selected to adjust for deriving the optimal associated performance index. The optimization problem is solved by the genetic algorithm （GA） with necessary constraints. Finally, the properties of the optimized valve are compared with those of the prototype workpiece, and the results prove that the dynamic performance indexes of the optimized valve are much better than those of the prototype workpiece.
文摘A maize (Zea mays L.) genome_specific repeated DNA sequence (clone MR64) has been transferred into one DH line of wheat through wheat (Triticum persicum Vav. ex Zhuk.) and maize cross. In the present study by RFLP analysis the authors proved that this DNA sequence could stably transmit into DH3 plants, the next generation derived from DH2 self_crossing. A similarity search in all DNA databases using BLASTN program showed that the DNA sequence of MR64 had as high as 93% identity to PREM_2 and 79% to Opie_2 in nucleotides. Both PREM_2 and Opie_2 are known as retrotransposons in maize genome, suggesting that MR64 likely is the partial sequence of a maize retrotransposon. Therefore, the results indicate that some retrotransposon might involve the DNA introgression from maize to wheat genome through wide fertilization. Stable inheritance of this maize genome_specific retrotransposon_like DNA in the wheat genome opens up the possibility of using retrotransposon as a new tool for gene tagging, function analysis, and insertional mutagenesis in wheat genome.
