In the 1960 s, America has entered a new historical period with recession in economy and increasingly bad social problem. Besides, Civil Rights Movement and women rights movement have been led by black people and wome...In the 1960 s, America has entered a new historical period with recession in economy and increasingly bad social problem. Besides, Civil Rights Movement and women rights movement have been led by black people and women for equal rights.With the development of these movements, the counter-cultural movement came into being, and the movement which represented a significant period in post-war youth cultural history was caused by the impending readjustment of social structure during the transition from industrial to post-industrial society in the 1960 s. American white middle class youth were disillusioned with the way their parent culture controlled the society and had no desire to become caught up in the machinery of social power themselves.The counter-cultural constituted a direct attack on the part of white middle class youth against the dominant ideological machinery set in place and maintained by its parent culture, and its influence has been maintained to the modern times. Except for the liberation of sex and drug, the most important symbol of the counter-culture is rock music. There is a close relationship between the counter-cultural movement and rock music. During the mid to late 1960 s rock music became a centrally significant medium for the dissemination of a range of social-political issues in counter-cultural movement. The period from the mid-1960 s to the early 1970 s represented the first time that popular music, a mass cultural form, had become a centrally significant medium for the dissemination of a range of sociopolitical issues, from US involvement in the Vietnam war to the Civil Rights Movements, to the rejection of western political and cultural ideology. As Eyerman and Jamison^([1])point out:‘Movement ideas, images,and feelings were disseminated in and through popular music and, at the same time, the movements of the times influenced developments, in both form and content, in popular music'.展开更多
Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement pro...Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement process of rock blocks in rock avalanche, due to the high velocity and impacts against obstructions. In view of the energy consumption theory for brittle rock fragmentation proposed by Bond, which relates energy to size reduction, a theoretical model is proposed to estimate the average fragment size for a moving rock block when it impacts against an obstruction. Then, different forms of motion are studied, with various drop heights and slope angles for the moving rock block. The calculated results reveal that the average fragment size decreases as the drop height increases, whether for free-fall or for a sliding or rolling rock block, and the decline in size is rapid for low heights and slow for increasing heights in the corresponding curves. Moreover, the average fragment size also decreases as the slope angle increases for a slidingrock block. In addition, a rolling rock block has a higher degree of fragmentation than a sliding rock block, even for the same slope angle and block volume. Finally, to compare with others' results, the approximate number of fragments is estimated for each calculated example, and the results show that the proposed model is applicable to a relatively isotropic moving rock block.展开更多
文摘In the 1960 s, America has entered a new historical period with recession in economy and increasingly bad social problem. Besides, Civil Rights Movement and women rights movement have been led by black people and women for equal rights.With the development of these movements, the counter-cultural movement came into being, and the movement which represented a significant period in post-war youth cultural history was caused by the impending readjustment of social structure during the transition from industrial to post-industrial society in the 1960 s. American white middle class youth were disillusioned with the way their parent culture controlled the society and had no desire to become caught up in the machinery of social power themselves.The counter-cultural constituted a direct attack on the part of white middle class youth against the dominant ideological machinery set in place and maintained by its parent culture, and its influence has been maintained to the modern times. Except for the liberation of sex and drug, the most important symbol of the counter-culture is rock music. There is a close relationship between the counter-cultural movement and rock music. During the mid to late 1960 s rock music became a centrally significant medium for the dissemination of a range of social-political issues in counter-cultural movement. The period from the mid-1960 s to the early 1970 s represented the first time that popular music, a mass cultural form, had become a centrally significant medium for the dissemination of a range of sociopolitical issues, from US involvement in the Vietnam war to the Civil Rights Movements, to the rejection of western political and cultural ideology. As Eyerman and Jamison^([1])point out:‘Movement ideas, images,and feelings were disseminated in and through popular music and, at the same time, the movements of the times influenced developments, in both form and content, in popular music'.
基金supported by the National Natural Science Foundation of China (41472272, 41225011)the Youth Science and Technology Fund of Sichuan Province (2016JQ0011)the Opening Fund of the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology) (SKLGP2013K015)
文摘Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement process of rock blocks in rock avalanche, due to the high velocity and impacts against obstructions. In view of the energy consumption theory for brittle rock fragmentation proposed by Bond, which relates energy to size reduction, a theoretical model is proposed to estimate the average fragment size for a moving rock block when it impacts against an obstruction. Then, different forms of motion are studied, with various drop heights and slope angles for the moving rock block. The calculated results reveal that the average fragment size decreases as the drop height increases, whether for free-fall or for a sliding or rolling rock block, and the decline in size is rapid for low heights and slow for increasing heights in the corresponding curves. Moreover, the average fragment size also decreases as the slope angle increases for a slidingrock block. In addition, a rolling rock block has a higher degree of fragmentation than a sliding rock block, even for the same slope angle and block volume. Finally, to compare with others' results, the approximate number of fragments is estimated for each calculated example, and the results show that the proposed model is applicable to a relatively isotropic moving rock block.
