We analyzed the songs of the Asian Stubtail (Urosphena squameiceps),a migratory passerine that breeds in northeast Asia.The possibility of individual identification of this species by songs was examined in a populatio...We analyzed the songs of the Asian Stubtail (Urosphena squameiceps),a migratory passerine that breeds in northeast Asia.The possibility of individual identification of this species by songs was examined in a population in northern China during the breeding season of 2010.Individuality was determined using discriminant function analysis,artificial neural networks and spectrographic cross-correlation.Our results show that,the rate of correct classification is satisfactory in this species,regardless of methods.From an applied perspective,spectrographic cross-correlation is most suitable.Besides its maximum rate of correct classification (89.4％),it does not require measurements of spectrograms,which is a necessity other methods and may introduce artificial errors.We hope that our result of individual identification on the basis of acoustic signals may open up a new research venue for this species.展开更多
A simply method to measure the thermal focal length of a LD end-pumped Nd.GdVO4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distri...A simply method to measure the thermal focal length of a LD end-pumped Nd.GdVO4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distribution behind the output mirror of lasers, the radius and the M^2 factor describing the quality of beam can be measured. The waists of the multi-mode field and the TEM00 mode can be deduced according to the law of multi-mode Gassian beam propagation. Based on the ABOD matrix theory of a stable resonator,the thermal focal length of the active medium can be easily obtained. The thermal focal length of a LD end-pumped Nd. GdVO~ laser has been measured and the experimental results agree with the theoretically analyzed values.展开更多
基金supported by National Natural Science Foundation of China(No.J0830630/J0106)
文摘We analyzed the songs of the Asian Stubtail (Urosphena squameiceps),a migratory passerine that breeds in northeast Asia.The possibility of individual identification of this species by songs was examined in a population in northern China during the breeding season of 2010.Individuality was determined using discriminant function analysis,artificial neural networks and spectrographic cross-correlation.Our results show that,the rate of correct classification is satisfactory in this species,regardless of methods.From an applied perspective,spectrographic cross-correlation is most suitable.Besides its maximum rate of correct classification (89.4％),it does not require measurements of spectrograms,which is a necessity other methods and may introduce artificial errors.We hope that our result of individual identification on the basis of acoustic signals may open up a new research venue for this species.
基金Supported by the National Natural Science Foundation of China(No.60478036)
文摘A simply method to measure the thermal focal length of a LD end-pumped Nd.GdVO4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distribution behind the output mirror of lasers, the radius and the M^2 factor describing the quality of beam can be measured. The waists of the multi-mode field and the TEM00 mode can be deduced according to the law of multi-mode Gassian beam propagation. Based on the ABOD matrix theory of a stable resonator,the thermal focal length of the active medium can be easily obtained. The thermal focal length of a LD end-pumped Nd. GdVO~ laser has been measured and the experimental results agree with the theoretically analyzed values.
