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本研究应用聚类分析的方法,对人离休髁突×片进行数字图像技术处理所获得的影像密度数值做了详细分析,取得人髁突不同区的骨密度分布及不同年龄阶段髁突密度变化的情况。该方法避免了人为因素的影响,其结果较客观地反映了髁突的骨质密度;为研究病理状态时髁突骨密度的改变提供参考。 相似文献
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Unconditional uniqueness of solution for $$\dot H^{s_c }$$ critical 4th order NLS in high dimensions 下载免费PDF全文
In this paper, we study the unconditional uniqueness of solution for the Cauchy problem of Ḣsc(0 ≤ sc < 2) critical nonlinear fourth-order Schrödinger equations i∂tu + Δ2u-εu=λ|u|αu. By employing paraproduct estimates and Strichartz estimates, we prove that unconditional uniqueness of solution holds in Ct(I; Ḣsc(Rd)) for d ≥ 11 and min{1-, (8)/(d-4)} ≥ α >(-(d-4)+√4(d-4)2+64)/4. 相似文献
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本文证明了, 在临界Besov 空间中, 速度的竖直方向具有大的初始值的三维不可压缩Navier-Stokes 方程的整体解是唯一存在的. 首先, 引进合适的权函数, 用以控制方程中的非线性项; 其次, 充分利用流体的不可压缩性质, 分别估计速度的水平分量和竖直分量以及压力的水平方向梯度和竖直方向梯度; 最后, 通过适当选取权函数的系数, 得到封闭的能量估计, 从而得到方程的整体适定性. 相似文献
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We focus our attention on the approximation of some nonlinear operators in adapted wavelet spaces. We show the interest of
the construction of scaling functions with a large number of zero moments. We present the convergence estimate of an algorithm
based on paraproducts for the approximation of nonlinear operators using wavelets connected to scaling functions with zero
moments. Numerical tests are performed on univariate examples.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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In this paper, we are concerned with the Cauchy problem of the two-dimensional (2D) fluid system with the linear Soret effect and Yudovich's type data. We obtain global unique solution for this system without imposing any smallness conditions on the initial data. Our methods mainly rely upon Littlewood–Paley theory and loss of regularity estimates. 相似文献
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We prove that for the 3D MHD equations with hyper-dissipations(-△)~α(1α5/4)the Hausdorff dimension of singular set at the first blowing up time is at most 5-4α,by means of physical and frequency localization,Bony's paraproduct and Littlewood-Paley theory. 相似文献
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In this paper, the Lp(Rn)-boundedness of the commutators generalized by BMO(Rn) function and the singular integral operator T with rough kernel Ω∈ Llog+ L(Sn-1) is proved by using the Bony's formula for the paraproduct of two functions. 相似文献