利用GPS速度场求解构造块体的运动参数   总被引：4，自引：0，他引：4  

彭兵 《测绘科学》2005,30(6):33-34,63

文章推导了利用GPS观测速度计算构造块体转动参数和变形参数的统一模型,并基于此模型,利用GPS速度场资料,计算了中国大陆六个一级块体的转动参数和变形参数。  相似文献   

全站仪不对中不整平条件下的测量     

郭剑琴  宣伟  余锐  纪志刚 《地理空间信息》2012,10(5):114-116

目前,全站仪广泛应用于工程测量,而在实际工作中,会出现全站仪测量无法实现对中整平或者对中整平后无法实施测量的情况。针对这种特殊情况,提出了一种全站仪测量的新思路,通过采用任意旋转角坐标转化的方法,可以将不对中不整平条件下全站仪测量的三维坐标观测值转换到已知坐标系中,并通过实验数据验证转换的精度。实践证明,该方法在实际应用中是可行的。  相似文献   

强潮汐激发地震火山活动的新证据   总被引：20，自引：4，他引：16       下载免费PDF全文

杨学祥  韩延本  陈震  乔琪源 《地球物理学报》2004,47(4):616-621

强潮汐与火山地震活动密切相关. 天文资料表明, 2000年6月到8月日本Izu半岛最活跃的火山地震活动正好处于天文大潮时期和日长变化最小值时期. 在厄尔尼诺事件和拉尼娜事件发生前后,东西太平洋海面高度分别升降40cm, 水均衡作用使洋壳反向升降13cm. 由此形成的东西太平洋地壳跷跷板运动加强了强潮汐对地震火山活动的激发作用.  相似文献   

地球内核的地震学研究进展   总被引：4，自引：4，他引：0  

李乐  周蕙兰  陈棋福 《地球物理学进展》2004,19(2):238-245

介绍和讨论了用地震学观测资料和方法研究内核所取得的各种不同的最新结果.内核差异旋转的研究结果争论很大,Souriau和宋晓东给出的差异转速值分别为(0±0.2)°/a和(0.15-1.1)°/a.内核上部数百公里厚度的层区内,西半球比东半球各向异性强,即存在明显的半球尺度上的差异.资料和研究表明,在内核浅部似乎是各向同性的,而其余部分是各向异性的,由此需要提出一个过渡带模型来解释内核各向异性的径向和横向变化.通过大量资料分析还发现,在半径约300km的中心区域,其各向异性比浅部更强.这成为"最内核"存在的证据,并从而展示了一个全新的内核结构:上内核、过渡带、下内核、最内核.介质品质因子的研究指出内核高波速区却是波动能量高衰减区,与在地幔中两者的相关规律性很不相同.内核的横波研究虽然更为困难,但也有少数学者做了努力.  相似文献   

关于强震观测中利用回转摆测量转动分量的讨论     

黄振平  王绍荣 《地震工程与工程振动》2004,24(5):167-170

本文阐述了地面转动对回转式拾振器反应的影响,指出目前使用的加速度计基本上均为回转式小折合摆长的加速度计,地面转动对摆反应的影响很小,可略去不计。由于在摆的输出中,转动分量所占的分量很小,故不能在丁程强震中采用现有加速度计来提取转动信息。本文给出了转动拾振器的2个方案：陀螺方案及双摆方案。  相似文献   

Asteroid observations at low phase angles: III. Brightness behavior of dark asteroids     

Vasilij G. Shevchenko  Vasilij G. Chiorny  Yury N. Krugly  Igor A. Tereschenko 《Icarus》2008,196(2):601-611

The results of photometric observations of eight main-belt asteroids with low surface albedo are presented. The magnitude-phase dependences including low phase angles (<1 deg) have been obtained for Asteroids 76 Freia (down to phase angle 0.1 deg, P-type), 190 Ismene (0.3 deg, P-type), 303 Josephina (0.2 deg, C-type), 309 Fraternitas (0.1 deg, C-type), 313 Chaldaea (0.1 deg, C-type), 444 Gyptis (0.8 deg, P-type), 615 Roswitha (0.1 deg, C-type), and 954 Li (0.03 deg, FCX-type). The behavior of brightness in the range of opposition effect is found to be practically linear for 190 Ismene with amplitude of opposition effect only 0.03 mag. Amplitudes of the opposition effect for other asteroids are close to a mean for this type. The obtained data allowed us also to determine the rotation periods of asteroids: 303 Josephina (12.497±0.001 h), 309 Fraternitas (11.205±0.005 h), 615 Roswitha (4.422±0.001 h) and 954 Li (7.207±0.002 h). The color indexes B-V, V-R and R-I have been determined for some asteroids.  相似文献   

3D DEM simulation of principal stress rotation in different planes of cross-anisotropic granular materials     

Long Xue  Niels P. Kruyt  Rui Wang  Jian-Min Zhang 《国际地质力学数值与分析法杂志》2019,43(14):2227-2250

Three-dimensional Discrete Element Method simulations have been performed to study the deformation of cross-anisotropic granular materials under principal stress rotation (PSR), for rotation planes oriented at different angles θ with respect to the bedding plane. The simulations have been conducted with a novel technique for applying specified stresses at three-dimensional boundaries. The results are qualitatively in agreement with experimental results from literature. Cumulative volume contraction is always observed under continuous PSR and increases with increasing θ. The dilatancy rate decreases with increasing number of PSR cycles, tending to zero. The noncoaxiality angle between the strain increment and the stress in the PSR plane increases with increasing number of cycles, reaching the same asymptotic value for samples of various densities and for various θ. Periodic oscillations of the dilatancy rate and noncoaxiality angle within each PSR cycle are observed with an increasing oscillation magnitude with increasing θ, due to the larger fabric anisotropy within the PSR plane. When θ = 30 or 60°, significant noncoaxial strain accumulation occurs in the plane perpendicular to the PSR plane due to the oblique angle between the PSR plane and the bedding plane, echoing the major principal fabric direction's being neither parallel nor perpendicular to the PSR plane. The macroscopic behavior of the samples is related to the microscopic parameters including coordination number and fabric anisotropy. With increasing number of cycles, the difference between normalized stress/strain/fabric increment tensors tends to become constant, with only a small lag between each pair, irrespective of θ.  相似文献   

A three‐dimensional displacement approach for analysis of laterally loaded piles in nonhomogeneous soil          下载免费PDF全文

Hiroyoshi Hirai 《国际地质力学数值与分析法杂志》2017,41(16):1605-1635

An analytical approach using the three‐dimensional displacement of a soil is investigated to provide analytical solutions of the horizontal response of a circular pile subjected to lateral loads in nonhomogeneous soil. The rocking stiffness coefficient of the pile shaft in homogeneous soil is derived from the analytical solution taking into account the three‐dimensional displacement represented in terms of scalar potentials in the elastic three‐dimensional analysis. The lateral stiffness coefficient of the pile shaft in nonhomogeneous soil is derived from the rocking stiffness coefficient taking into account the rocking rotation of a rigid pile shaft. The relationship between horizontal displacement, rotation, moment, and shear force of a pile subjected to horizontal loads in nonhomogeneous soil is obtainable in the form of the recurrence equation. The formulation of the lateral displacement and rotation of the pile base subjected to lateral loads in nonhomogeneous soils is presented by taking into account Mindlin's equation and the equivalent thickness for soil layers in the equivalent elastic method. There is little difference between lateral, rocking, and couple stiffness coefficients each obtained from both the two‐dimensional and three‐dimensional methods except for the case of Poisson's ratio near 0.5. The comparison of results calculated by the current method for a pile subjected to lateral loads in homogeneous and nonhomogeneous soils has shown good agreement with those obtained from analytical and numerical methods. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Dimensions and equilibrium structures of the primary component of the nonsynchronous binary systems     

《New Astronomy》2014

Rotating stars and stars in the synchronous binaries have been extensively studied in literature. However, there are only few studies that have investigated the problems of the nonsynchronous binaries. In the present paper, we have made an attempt to study the various dimensions and equilibrium structures of the primary component of the nonsynchronous binaries. We have used the first approximation theory of Limber (1963) along with the methodology as that proposed by Mohan and Saxena (1983) for the present study. The objective of this paper is to check the effect of nonsynchronism on the various dimensions and equilibrium structures of the primary components of the binary systems. The results of the present study shows that there is change in the dimensions and equilibrium structures of the primary component of the binary systems due to nonsynchronism, and this change is more appreciable when the difference between the angular velocities of rotation and revolution is large.  相似文献   

预测函数算法在同步发电机励磁系统中的应用     

倪家健  郭伟  王波  吴青  曹雷  尤辉  方灏 《南京气象学院学报》2011,(5):475-480

预测函数控制(Predictive Function Control)方法克服了传统预测控制算法复杂、在线计算量大的缺点,具有算法简单、计算量小、跟踪速度快和精度高等优点,适合同步发电机励磁等快速系统.介绍了预测函数控制(PFC)的基本原理和特点,成功地将预测函数控制算法运用到同步发电机励磁系统中.仿真结果表明:预测函数控制算法的控制效果明显优于PID和分数阶PID控制器,其对同步发电机启动时的机端电压、短路时的电压和断路时的电压等都能起到良好的控制作用.  相似文献