研究目的:为选择出适用于钢轨导波无损检测的优势模态,采用半解析有限元法并基于哈密顿原理建立钢轨导波传播的控制方程,求解0~100 k Hz频率范围内的钢轨导波频散特性曲线。通过建立有限元模型对钢轨低频范围内的振动模态进行分析,验证...研究目的:为选择出适用于钢轨导波无损检测的优势模态,采用半解析有限元法并基于哈密顿原理建立钢轨导波传播的控制方程,求解0~100 k Hz频率范围内的钢轨导波频散特性曲线。通过建立有限元模型对钢轨低频范围内的振动模态进行分析,验证半解析有限元法的准确性。在此基础上,提出将有限元法与半解析有限元法相结合的方法,用以分类并追踪钢轨理想导波模态,并根据相应的振型对理想模态导波进行激励和验证。研究结论:(1)随着频率的增大,钢轨导波振动模态数目迅速增加,但频散效应呈减小趋势;(2)对于钢轨基本振动模态,其横截面变形由整体变形逐渐演化为局部变形,其中扭转振动模态适用于轨腰检测,横向弯曲振动模态及竖向弯曲振动模态适用于轨底缺陷的检测;(3)在理想导波模态最大变形位置处施加激励荷载可以成功地激励出理想的导波;(4)本研究结果可为导波传感器设计与优化以及检测试验提供理论参考。展开更多
This paper described the main four basic models of ideal landscape in the Mount Lushan National Park as Kunlunshan model, Xumishan model, Peach flower land model, Christian model. Five typical places in Mount Lushan w...This paper described the main four basic models of ideal landscape in the Mount Lushan National Park as Kunlunshan model, Xumishan model, Peach flower land model, Christian model. Five typical places in Mount Lushan with the ideal landscape characteristics like the East Grove Temple, White Deer Cave Academy, Simplicity and Tranquility Monastery, Lushan Valley, and Villa-cluster of the East Valley were analyzed, and the integration of the basic models for each place was discussed to make the realistic landscape conform to the ideal needs. Moreover, the discussions also involved the characteristics of ideal landscape that are featured in resource, culture, structure, function, process, scale and region. In conclusion, ideal landscape in the Mount Lushan National Park was the product of the interaction between human and nature. Mount Lushan inherits the essence of Chinese traditional culture with a history of more than 1000 years; and it also absorbs the manna of the Western culture as well as the exchanges between nature and humanities together with the conflict and adaptation among different cultures. The natural landscape could be satisfied with the survival demand and cultural taste of mankind by the way of ecological planning.展开更多
The concept of quasi-coincidence of a fuzzy interval value in an interval valued fuzzy set is considered. In fact, this concept is a generalized concept of the quasi-coincidence of a fuzzy point in a fuzzy set. By usi...The concept of quasi-coincidence of a fuzzy interval value in an interval valued fuzzy set is considered. In fact, this concept is a generalized concept of the quasi-coincidence of a fuzzy point in a fuzzy set. By using this new concept, the authors define the notion of interval valued （∈, ∈ Vq）fuzzy h-ideals of hemirings and study their related properties. In addition, the authors also extend the concept of a fuzzy subgroup with thresholds to the concept of an interval valued fuzzy h-ideal with thresholds in hemirings.展开更多
文摘研究目的:为选择出适用于钢轨导波无损检测的优势模态,采用半解析有限元法并基于哈密顿原理建立钢轨导波传播的控制方程,求解0~100 k Hz频率范围内的钢轨导波频散特性曲线。通过建立有限元模型对钢轨低频范围内的振动模态进行分析,验证半解析有限元法的准确性。在此基础上,提出将有限元法与半解析有限元法相结合的方法,用以分类并追踪钢轨理想导波模态,并根据相应的振型对理想模态导波进行激励和验证。研究结论:(1)随着频率的增大,钢轨导波振动模态数目迅速增加,但频散效应呈减小趋势;(2)对于钢轨基本振动模态,其横截面变形由整体变形逐渐演化为局部变形,其中扭转振动模态适用于轨腰检测,横向弯曲振动模态及竖向弯曲振动模态适用于轨底缺陷的检测;(3)在理想导波模态最大变形位置处施加激励荷载可以成功地激励出理想的导波;(4)本研究结果可为导波传感器设计与优化以及检测试验提供理论参考。
基金supported by "Cities Farming for the Future, RUAF-CFF"funded by DGIS of the Netherlands and IDRC of Canada+2 种基金the National Natural Science Foundation of China (70503007)the Graduate’s Scientific Research Foundation of Hunan Provincethe Graduate’s Scientific Research Foundation of Central South University of Forestry and Technology (2006bx03)
文摘This paper described the main four basic models of ideal landscape in the Mount Lushan National Park as Kunlunshan model, Xumishan model, Peach flower land model, Christian model. Five typical places in Mount Lushan with the ideal landscape characteristics like the East Grove Temple, White Deer Cave Academy, Simplicity and Tranquility Monastery, Lushan Valley, and Villa-cluster of the East Valley were analyzed, and the integration of the basic models for each place was discussed to make the realistic landscape conform to the ideal needs. Moreover, the discussions also involved the characteristics of ideal landscape that are featured in resource, culture, structure, function, process, scale and region. In conclusion, ideal landscape in the Mount Lushan National Park was the product of the interaction between human and nature. Mount Lushan inherits the essence of Chinese traditional culture with a history of more than 1000 years; and it also absorbs the manna of the Western culture as well as the exchanges between nature and humanities together with the conflict and adaptation among different cultures. The natural landscape could be satisfied with the survival demand and cultural taste of mankind by the way of ecological planning.
基金Supported by the National Natural Science Foundation of China under Grant No.60474022the Key Science Foundation of Education Committee of Hubei Province,China under Grant No.D200729003
文摘The concept of quasi-coincidence of a fuzzy interval value in an interval valued fuzzy set is considered. In fact, this concept is a generalized concept of the quasi-coincidence of a fuzzy point in a fuzzy set. By using this new concept, the authors define the notion of interval valued （∈, ∈ Vq）fuzzy h-ideals of hemirings and study their related properties. In addition, the authors also extend the concept of a fuzzy subgroup with thresholds to the concept of an interval valued fuzzy h-ideal with thresholds in hemirings.
