共查询到19条相似文献，搜索用时 78 毫秒
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本文给出了循环群的相关定义并论述了循环群的几个重要性质,得出循环群是交换群,但其逆命题不一定成立;再次探讨了循环群与交换群的相关定理,并借助例题进行分析应用,指出学习循环群的现实意义。 相似文献
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设p为奇素数(p≠3,7),G是Sylow 2-子群为8阶循环群C8的8p3阶群,那么:当p≡1(mod 8)时,G恰有87个彼此不同构的类型;当p≡5(mod 8)时,G恰有41个彼此不同构的类型;当p≡3或7(mod 8)时,G恰有21个彼此不同构的类型. 相似文献
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周金植 《湖州师范学院学报》2002,24(6):82-84
循环群是离散数学过程中一个比较抽象的内容，对学生的学习来说也是一个难点。通过对基本定量、例题的分析，对如何求解循环群的生成元、循环群的子群等问题，我们给出明确方法，使其具体化，从而提高教学效果。 相似文献
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研究了LZ50车轴钢的循环相关特性,循环疲劳特性及循环应力-应变关系。试验结果表明:LZ50车轴钢的循环疲劳特性曲线及循环应力-应变曲线很好地符合双对数线性关系;其循环相关特性表现为先循环软化,稳定后又发生循环硬化,而且循环软化和循环硬化的程度随控制应变的不同而不同。 相似文献
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There exists a critical cyclic stress ratio when sand or clay is subjected to cyclic loading. It is an index distinguishing stable state or failure state. The soil static and dynamic universal triaxial and torsional shear apparatus developed by Dalian University of Technology in China was employed to perform different types of tests on saturated soft marine clay in the Yangtze estuary. Undisturbed samples were subjected to undrained cyclic vertical and torsional coupling shear and cyclic torsional shear after three-directional anisotropic consolidation with different initial consolidation parameters. The effects of initial orientation angle of major principal stress, initial ratio of deviatoric stress, initial coefficient of intermediate principal stress and stress mode of cyclic shear on the critical cyclic stress ratio were investigated. It is found that the critical cyclic stress ratio decreases significantly with increasing initial orientation angle of major principal stress and initial ratio of deviatoric stress. Compared with the effects of the initial orientation angle of major principal stress and initial ratio of deviatoric stress, the effect of initial coefficient of intermediate principal stress is less evident. Under the same consolidation condition, the critical cyclic stress ratio from the cyclic coupling shear test is lower than that from the cyclic torsional shear test, indicating that the stress mode of cyclic shear has an obvious effect on the critical cyclic stress ratio. The main reason is that the continuous rotation in principal stress directions during cyclic coupling shear damages the original structure of soil more than the cyclic torsional shear does. 相似文献
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曾春霞 《湖南广播电视大学学报》2009,(3):26-29
循环经济是经济增长的新模式,是实现可持续发展的重要途径,而生态文明理念是发展循环经济的基点。文章小结了生态文明和循环经济的内涵和特征以及两者的内在联系,分析了衡阳经济发展现状和发展循环经济的意义,并对衡阳发展循环经济的可行性和策略进行了探讨。 相似文献
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对调质42CrMo钢进行室温下各种应力循环和对称应变循环的低周疲劳实验,揭示材料的循环软化特性,棘轮变形和低周疲劳特性以及棘轮-疲劳交互作用。结果表明,调质42CrMo钢体现出明显的循环软化;在应力幅值或平均应力较高时,试样的棘轮变形较大,其破坏形式为延性破坏,而在应力水平较低时,材料的破坏由疲劳裂纹扩展所致的脆性断裂引起;材料在应力循环下的低周疲劳寿命由于有棘轮变形的产生而受到平均应力、应力幅值、最大应力和应变比等多种因素的影响。 相似文献
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循环统计量分析与包络解调分析的对比 总被引：1，自引：0，他引：1
In this paper,demodulation performance of first-order cyclic statistics and second-order cyclic stais for amplitude modulation signals is introduced.By theoretical research,it is proved that cyclic mean does not possess demodulation performance for amplitude modulation signals,but cyclic autocorrelation function can extract frequency components from amplitude modulation signals.Based on the above,both cyclic autocorrelation function and envelope demodulation based on Hilbert transfrom are compared.The results show that the two kinds of analysis methods have similar performance for demodulation,in the mean time it is pointed out that they also possess essential distinction,and cyclic autocorrelation function is better to demodulate amplitude modulation signals. 相似文献
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Failure criterion of saturated soft clay is studied under cyclic loads through different experiments. A large number of cyclic torsional shear and cyclic triaxial tests on saturated soft clay under unconsolidated undrained condition are conducted. From the test result analysis, it is seen that the failure of saturated soft clay under static and cyclic loads satisfies Mises criterion. The result from different test stress states is not related to the test stress states or confining pressures. It can be applied in general stress states. Then according to the Mises criterion, the equivalent relationship on failure moment between the test stress state and the general stress state can be established. So the cyclic mechanics characteristics of saturated soft clay at failure moment are clarified in this paper. Furthermore, a theory basis is provided for using pseudo-static elasto-plastic cyclic strength model to evaluate cyclic bearing capacity. 相似文献
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Constitutive model of saturated soft clay with cyclic loads under unconsolidated undrained condition
An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and extension tests were conducted to study the parameters of the model. Results showed that the relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain were nearly unique, when the initial octahedral shear stress ratios of specimens were equal to 0.3, 0.5 and 0.7. The relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain determined from the cyclic triaxial compression tests were basically the same as those determined from the cyclic triaxial extension tests. Furthermore, the relationships were not related to the initial stress condition, the test stress state and the octahedral cyclic shear stress ratio. The relationships determined from the cyclic triaxial tests under no deviatoric stress were basically the same as those determined from the cyclic triaxial tests under deviatoric stress. The change of the octahedral cyclic accumulative strain with the number of cycles was unique under different tests stress states. An equivalent visco-elastic constitutive model of saturated soft clay under UU condition was initially established. 相似文献
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为克服LTI系统线性卷积运算量过大的问题,给定适当条件,使圆周卷积替代线性卷积,利用圆周卷积的频谱特性降低线性卷积的复杂度,对圆周卷积与线性卷积的可替代性进行论证,并对圆周卷积的频谱特性及其算法复杂度进行了分析. 相似文献