In the study,an improved time difference mapping(I-TDM) method is proposed to locate the acoustic emission(AE) source in a composite plate.The acoustic velocity in a composite plate with fiber fractures and matrix cra...In the study,an improved time difference mapping(I-TDM) method is proposed to locate the acoustic emission(AE) source in a composite plate.The acoustic velocity in a composite plate with fiber fractures and matrix crack defects largely varies with the propagation direction.In the proposed method,the prebuilt database is adopted in order to avoid the consideration of the inconsistent propagation speed of waves in a plate.In addition,according to the proposed method,the requirements for wave propagation modes or the sensor layout are not strict in the experiment.Firstly,in order to quickly and accurately select and delete the pseudo AE events in a large number of AE data,the clustering algorithm was used to automatically identify and select the highly correlated AE events on each grid node and construct a time difference training database.Secondly,the interpolation compensation algorithm was adopted to increase grid density and improve grid resolution.Finally,the actual location of the source in the test area was verified by using the weighted difference algorithm.Theoretical analysis and experimental results showed that the average location error of the sound source obtained by the I-TDM method was 18.0 mm,which was lower than that obtained by the traditional time difference mapping(TDM) method,26.5 mm.After the I-TDM method was adopted,the corresponding average relative error was reduced from 5.3% to 3.6% and the overall running time was reduced from 5 h to 16.87 s.The I-TDM method can effectively improve the location precision of the sound source in a composite plate.展开更多
Neonatal diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F4 is a common and serious disease,resulting in significant economical loss in the pig industry.The locus encoding ETEC F4 receptor has been mapped to ...Neonatal diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F4 is a common and serious disease,resulting in significant economical loss in the pig industry.The locus encoding ETEC F4 receptor has been mapped to pig chromosome(SSC)13q41,and one of the most significantly linked markers is S0075.In this study,we selected three genes including SLC12A8,MYLK and KPNA1 from a chromosomal region flanking S0075 on SSC13 to develop pig specific sequence tagged sites(STS).Seven single nucleotide polymorphisms were identified in the three pig STS using DNA of four full-sib susceptible and resistant animals in a White Duroc×Erhualian intercross.All grandparents,parents and 755 offspring in the intercross were genotyped for three polymorphisms,including SLC12A8 g.159A>G,MYLK g.1673A>G and KPNA1 g.306A>G.Family-based transmission disequilibrium test(TDT)revealed that all polymorphisms and the corresponding haplotypes are significantly associated with ETEC F4ab/ac(especially F4ac)brush border adhesion phenotypes,indicating that these polymor-phism are in linkage disequlibrium with causal mutation(s)of the gene encoding ETEC F4ab/ac receptor.Our results strengthen the evidence for the involvement of SSC13q41 in high acquiring risk of ETEC F4ab/ac infection,and provide novel polymorphic markers for fine mapping of the ETEC F4ab/ac receptor locus.展开更多
基金supported by the National Natural Science Foundation of China(11772014,51475012,11272021)the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(CIT&TCD201304048)
文摘In the study,an improved time difference mapping(I-TDM) method is proposed to locate the acoustic emission(AE) source in a composite plate.The acoustic velocity in a composite plate with fiber fractures and matrix crack defects largely varies with the propagation direction.In the proposed method,the prebuilt database is adopted in order to avoid the consideration of the inconsistent propagation speed of waves in a plate.In addition,according to the proposed method,the requirements for wave propagation modes or the sensor layout are not strict in the experiment.Firstly,in order to quickly and accurately select and delete the pseudo AE events in a large number of AE data,the clustering algorithm was used to automatically identify and select the highly correlated AE events on each grid node and construct a time difference training database.Secondly,the interpolation compensation algorithm was adopted to increase grid density and improve grid resolution.Finally,the actual location of the source in the test area was verified by using the weighted difference algorithm.Theoretical analysis and experimental results showed that the average location error of the sound source obtained by the I-TDM method was 18.0 mm,which was lower than that obtained by the traditional time difference mapping(TDM) method,26.5 mm.After the I-TDM method was adopted,the corresponding average relative error was reduced from 5.3% to 3.6% and the overall running time was reduced from 5 h to 16.87 s.The I-TDM method can effectively improve the location precision of the sound source in a composite plate.
基金National High Technology Research and Development Program of China("863"Program)(Grant No.2006AA10Z194)Jiangxi Provincial KeyResearch Project
文摘Neonatal diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F4 is a common and serious disease,resulting in significant economical loss in the pig industry.The locus encoding ETEC F4 receptor has been mapped to pig chromosome(SSC)13q41,and one of the most significantly linked markers is S0075.In this study,we selected three genes including SLC12A8,MYLK and KPNA1 from a chromosomal region flanking S0075 on SSC13 to develop pig specific sequence tagged sites(STS).Seven single nucleotide polymorphisms were identified in the three pig STS using DNA of four full-sib susceptible and resistant animals in a White Duroc×Erhualian intercross.All grandparents,parents and 755 offspring in the intercross were genotyped for three polymorphisms,including SLC12A8 g.159A>G,MYLK g.1673A>G and KPNA1 g.306A>G.Family-based transmission disequilibrium test(TDT)revealed that all polymorphisms and the corresponding haplotypes are significantly associated with ETEC F4ab/ac(especially F4ac)brush border adhesion phenotypes,indicating that these polymor-phism are in linkage disequlibrium with causal mutation(s)of the gene encoding ETEC F4ab/ac receptor.Our results strengthen the evidence for the involvement of SSC13q41 in high acquiring risk of ETEC F4ab/ac infection,and provide novel polymorphic markers for fine mapping of the ETEC F4ab/ac receptor locus.
