共查询到7条相似文献,搜索用时 46 毫秒
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均数理论在确定未来震中位置中的应用 总被引:1,自引:0,他引:1
应用MDCB方法确定未来的发展地点,主要是用多台MDCB型仪器测出的异常方位角进行交汇。如何确定哪个交汇点有可能发展是关键的问题。应用均数数学理论中对从偶数求解的逆向运算方法,可为地震短临预报研究提供一种新的研究思路。 相似文献
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弹性波反射法在桩基检测中的理论与应用 总被引:1,自引:0,他引:1
根据波动理论探讨了弹性波在砼桩中的传播衰减规律及反射特征,提出了判断桩基质量的有关理论依据,并结合工程实例应用弹性波反射法讨论了时域、频域分析法的基本原理及存在问题. 相似文献
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SHAO Xuejun XIA Zhenhuan ①Lecturer Deportment of Hydraulic Engineering Tsinghua University Beijing China ②Professor Department of Hydraulic Engineering Tsinghua University Beijing China 《国际泥沙研究》1991,(2)
The random motion of sediment particles suspended in a turbulent flow is studied by means of stochastic process. Results of analysis of particle's frequency response to the random force exerted on the particle due to fluid turbulence suggest that only the lower part of the whole frequency range of the eddy motion will govern the motion of the particle. The mean values of particle velocity and displacement in the vertical direc- tion are calculated and it is found that particle velocity vp- can be decomposed into a mean motion and a velocity fluctuation vp- , where is equal to the fall velocity in tranquil fluid. An Ito^ random differential equation for particle dis- placement Yp is developed, from which a Fokker-Planck equation for the probability density function p(y,t) is derived on the basis of the theory of Markov process, where y denotes the vertical coordinate. The vertical distribution of the particle is thus interrelated to the random motion of the particle. The an effect that a particle will be subject to in the neighborhood or the bottom boundary is taken into consideration and a corresponding Fokker-Planck equation is developed. Analytical solution of the Fok- ker-Planck equation including the lift force effect shows that probability density p(y,t) for the particle displacement has a maximum value at y = H where the perpen- dicular component of the lift force balances the particle gravity. This theoretical result agrees with experimental observations as reported in literature. 相似文献
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用地震活动性参数(地震频度N,地震能量E和地震b值)的二维空间等值线计算机扫描技术,系统地追踪了1983年菏泽5.9级地震前后三项地震活动性参数的空间动态演化情况。结果表明,菏泽5.9级地震前1-4年,河北平原断陷南部地区特别是其东界聊考断裂带地震活动异常增强,地震频度增高,地震能量释放加速而地震b值降低;地震活动增强区的长度约200余公里,未来主震发生于地震活动增强区的边缘;震后约一年左右震中周 相似文献