A new polarization rotator based on the silica photonic crystal fiber is proposed. The proposed polarization rotator photonic crystal fiber （PR-PCF） possesses a triangle jigsaw-shape core region. The full-vector fin...A new polarization rotator based on the silica photonic crystal fiber is proposed. The proposed polarization rotator photonic crystal fiber （PR-PCF） possesses a triangle jigsaw-shape core region. The full-vector finite-element method is used to analyze the phenomenon of polarization conversion between the quasi-TE and quasi-TM modes. Numerical simulations show that the wavelengths of 1.31 μm and 1.55 μm are converted with a nearly 100% polarization conversion ratio with their matched coupling length and has a relatively strong realistic fabrication tolerance - 100 nm on the y axis and 50 nm on the x axis. The full vectorial finite difference beam propagation method is used to confirm the performance of the proposed PR-PCF.展开更多
An acoustic analysis of the intonation of statements and questions in American English was conducted, followed by a comparison with the intonation of statements and questions in British English, firstly in order to de...An acoustic analysis of the intonation of statements and questions in American English was conducted, followed by a comparison with the intonation of statements and questions in British English, firstly in order to determine at what point in statements and questions F0 tends to significantly diverge, and secondly to obtain an understanding of the basic similarities and differences between F0 movement in statements and questions in American and British English. Pitch range and pitch fluctuation measurements of six statements and six matching declarative questions in American English were taken at the word level, compared with those of British English taken by Guo [7], and checked for significant differences based on word position(sentence-initial, sentence-medial, and sentence-final) and modality(statements and questions) using statistical analysis. The results indicate that 1) in statements, both varieties of English demonstrated very similar pitch fluctuation, while American English demonstrated wider word pitch ranges than those in British English;2) in questions, the terminal rise in American English was primarily demonstrated by a rising top line, while the terminal rise in British English was primarily demonstrated by a falling bottom line;3) statements and questions in American English demonstrated a significant change in pitch fluctuation beginning in the sentence-medial word and a significant change in both pitch range and pitch fluctuation in the sentence-final word;and 4) statements and questions in British English demonstrated a significant change in pitch range location(or key) beginning in the sentence-initial word, a significant change in pitch fluctuation in the sentence-medial word, and a significant change in both pitch range and pitch fluctuation in the sentence-final word.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274181,10974100,61203204,and 10674075)the Doctoral Scientific Fund Project of the Ministry of Education of China(Grant No.20120031110033)the Tianjin Key Program of Application Foundations and Future Technology Research Project,China(Grant No.10JCZDJC24300)
文摘A new polarization rotator based on the silica photonic crystal fiber is proposed. The proposed polarization rotator photonic crystal fiber （PR-PCF） possesses a triangle jigsaw-shape core region. The full-vector finite-element method is used to analyze the phenomenon of polarization conversion between the quasi-TE and quasi-TM modes. Numerical simulations show that the wavelengths of 1.31 μm and 1.55 μm are converted with a nearly 100% polarization conversion ratio with their matched coupling length and has a relatively strong realistic fabrication tolerance - 100 nm on the y axis and 50 nm on the x axis. The full vectorial finite difference beam propagation method is used to confirm the performance of the proposed PR-PCF.
文摘An acoustic analysis of the intonation of statements and questions in American English was conducted, followed by a comparison with the intonation of statements and questions in British English, firstly in order to determine at what point in statements and questions F0 tends to significantly diverge, and secondly to obtain an understanding of the basic similarities and differences between F0 movement in statements and questions in American and British English. Pitch range and pitch fluctuation measurements of six statements and six matching declarative questions in American English were taken at the word level, compared with those of British English taken by Guo [7], and checked for significant differences based on word position(sentence-initial, sentence-medial, and sentence-final) and modality(statements and questions) using statistical analysis. The results indicate that 1) in statements, both varieties of English demonstrated very similar pitch fluctuation, while American English demonstrated wider word pitch ranges than those in British English;2) in questions, the terminal rise in American English was primarily demonstrated by a rising top line, while the terminal rise in British English was primarily demonstrated by a falling bottom line;3) statements and questions in American English demonstrated a significant change in pitch fluctuation beginning in the sentence-medial word and a significant change in both pitch range and pitch fluctuation in the sentence-final word;and 4) statements and questions in British English demonstrated a significant change in pitch range location(or key) beginning in the sentence-initial word, a significant change in pitch fluctuation in the sentence-medial word, and a significant change in both pitch range and pitch fluctuation in the sentence-final word.
