针对声学边界元法中解的非唯一性和奇异积分问题,基于组合亥姆霍兹积分方程公式(combined helmholtz integral equation formulation,CHIEF)法思想,将常规边界元方程和等效源方程进行联立,并利用两者方程系数矩阵间的耦合等价关系,间接...针对声学边界元法中解的非唯一性和奇异积分问题,基于组合亥姆霍兹积分方程公式(combined helmholtz integral equation formulation,CHIEF)法思想,将常规边界元方程和等效源方程进行联立,并利用两者方程系数矩阵间的耦合等价关系,间接替换计算常规边界元法中的奇异系数矩阵,进而提出一种具有全频域唯一解、高计算精度和高稳定性的耦合CHIEF法。该方法将等效源方程作为补充方程,不仅解决了传统CHIEF法内点补充方程失效的问题,而且矩阵的间接替换计算避免了直接计算奇异积分,显著提高了计算效率和精度。通过声辐射和声散射的典型算例对比了所提方法、常规边界元法、常规Burton-Miller法和等效源法的计算效果。结果表明,所提方法不仅在全波数域内均能获得唯一解,且其计算精度和效率均优于常规边界元法和常规Burton-Miller方法,其系数矩阵条件数远低于等效源法。展开更多
The Ransom of Red Chief is a short story written by O·Henry. Some critics regard it as a plot story but some do not. A typical plot story should focus on the plot :using techniques such as flashback or foreshadow...The Ransom of Red Chief is a short story written by O·Henry. Some critics regard it as a plot story but some do not. A typical plot story should focus on the plot :using techniques such as flashback or foreshadowing to unfold the plot and containing exposition, complication, climax, resolution, conclusion to rich the plot. The main characters are presented with internal and external conflicts as well. In this thesis, a detailed analysis will be presented to prove that this story is really a plot story.展开更多
Doris Lessing is one of the most influential writers in English. The colonialism, one of her most concerned topics, is often revealed in many of her early works and so is in The Old Chief Mshlanga. In this story, Less...Doris Lessing is one of the most influential writers in English. The colonialism, one of her most concerned topics, is often revealed in many of her early works and so is in The Old Chief Mshlanga. In this story, Lessing first employs a third-person narrator and then a first-person narrator, both of whom adopt the narrative perspective from the protagonist within the story.What the two different person-narrators really differ is in the narrative voice. The narrative voice of the third-person narrator comes from the narrator outside the story, while the other one comes from the protagonist within the story. It is by means of the same perspective and the different narrative voice that Lessing vividly reveals the colonialism in The Old Chief Mshlanga.展开更多
文摘针对声学边界元法中解的非唯一性和奇异积分问题,基于组合亥姆霍兹积分方程公式(combined helmholtz integral equation formulation,CHIEF)法思想,将常规边界元方程和等效源方程进行联立,并利用两者方程系数矩阵间的耦合等价关系,间接替换计算常规边界元法中的奇异系数矩阵,进而提出一种具有全频域唯一解、高计算精度和高稳定性的耦合CHIEF法。该方法将等效源方程作为补充方程,不仅解决了传统CHIEF法内点补充方程失效的问题,而且矩阵的间接替换计算避免了直接计算奇异积分,显著提高了计算效率和精度。通过声辐射和声散射的典型算例对比了所提方法、常规边界元法、常规Burton-Miller法和等效源法的计算效果。结果表明,所提方法不仅在全波数域内均能获得唯一解,且其计算精度和效率均优于常规边界元法和常规Burton-Miller方法,其系数矩阵条件数远低于等效源法。
文摘The Ransom of Red Chief is a short story written by O·Henry. Some critics regard it as a plot story but some do not. A typical plot story should focus on the plot :using techniques such as flashback or foreshadowing to unfold the plot and containing exposition, complication, climax, resolution, conclusion to rich the plot. The main characters are presented with internal and external conflicts as well. In this thesis, a detailed analysis will be presented to prove that this story is really a plot story.
文摘Doris Lessing is one of the most influential writers in English. The colonialism, one of her most concerned topics, is often revealed in many of her early works and so is in The Old Chief Mshlanga. In this story, Lessing first employs a third-person narrator and then a first-person narrator, both of whom adopt the narrative perspective from the protagonist within the story.What the two different person-narrators really differ is in the narrative voice. The narrative voice of the third-person narrator comes from the narrator outside the story, while the other one comes from the protagonist within the story. It is by means of the same perspective and the different narrative voice that Lessing vividly reveals the colonialism in The Old Chief Mshlanga.
