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
针对变速定桨风力发电机组(wind energy conversionsystem,WECS),提出一种简单有效的全风速功率控制策略,不仅可实现机组在全风速范围内的最大功率点跟踪(maximum power point tracking,MPPT)、恒转速以及恒功率控制,还可实现3种工况之...针对变速定桨风力发电机组(wind energy conversionsystem,WECS),提出一种简单有效的全风速功率控制策略,不仅可实现机组在全风速范围内的最大功率点跟踪(maximum power point tracking,MPPT)、恒转速以及恒功率控制,还可实现3种工况之间的自然过渡。首先对其工作原理进行详细地分析,并建立一套实验平台,展开实验研究,验证该方法的可行性及存在的问题;随后,进一步提出一种软失速控制策略,对其工作原理和年发电量的损失情况进行详细分析,论证该方法的可行性和优越性,并展开实验研究。通过与全风速控制策略的对比分析发现,软失速控制策略能显著地降低机组在高风速区的瞬态载荷,延长其使用寿命,并能大幅地降低后级变换器和发电机的额定容量,控制成本。展开更多
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.
文摘针对变速定桨风力发电机组(wind energy conversionsystem,WECS),提出一种简单有效的全风速功率控制策略,不仅可实现机组在全风速范围内的最大功率点跟踪(maximum power point tracking,MPPT)、恒转速以及恒功率控制,还可实现3种工况之间的自然过渡。首先对其工作原理进行详细地分析,并建立一套实验平台,展开实验研究,验证该方法的可行性及存在的问题;随后,进一步提出一种软失速控制策略,对其工作原理和年发电量的损失情况进行详细分析,论证该方法的可行性和优越性,并展开实验研究。通过与全风速控制策略的对比分析发现,软失速控制策略能显著地降低机组在高风速区的瞬态载荷,延长其使用寿命,并能大幅地降低后级变换器和发电机的额定容量,控制成本。
