最著名的噪声函数法就是K en Perlin于20世纪80年代提出的Perlin噪声,它被广泛应用于真实物体的模拟。文章采用Perlin噪声方法来模拟破旧木纹的效果,发现采用一维、二维噪声合成的方法可以产生特别的效果;另外,通过加入几何映射,可使效...最著名的噪声函数法就是K en Perlin于20世纪80年代提出的Perlin噪声,它被广泛应用于真实物体的模拟。文章采用Perlin噪声方法来模拟破旧木纹的效果,发现采用一维、二维噪声合成的方法可以产生特别的效果;另外,通过加入几何映射,可使效果更加显著。展开更多
In this paper, the authors introduce a class of product anisotropic singular integral operators, whose kernels are adapted to the action of a pair A := (A1, A2) of expansive dilations on R n and R m , respectively. Th...In this paper, the authors introduce a class of product anisotropic singular integral operators, whose kernels are adapted to the action of a pair A := (A1, A2) of expansive dilations on R n and R m , respectively. This class is a generalization of product singular integrals with convolution kernels introduced in the isotropic setting by Fefferman and Stein. The authors establish the boundedness of these operators in weighted Lebesgue and Hardy spaces with weights in product A∞ Muckenhoupt weights on R n × R m . These results are new even in the unweighted setting for product anisotropic Hardy spaces.展开更多
A new magnetopause model is proposed based on observation results, in which the magnetic-field includes one constant component and one monotomcally increasing component, so that magnetic field shear exists during the ...A new magnetopause model is proposed based on observation results, in which the magnetic-field includes one constant component and one monotomcally increasing component, so that magnetic field shear exists during the intervals when the interplanetary magnetic field has a northward component. Under this model, a completely analytical self-consistent equilibrium distribution function is derived based on the Vlasov-Maxwell equations. Through the analysis of this distribution function and its moments, the following can be concluded: (i) The equilibrium distribution function consists of a homogeneous Maxwellian distribution and two inhomogeneous shifted-Maxwellian distributions. There are 'hole' and 'bump' structures which have different cross-field drift velocities in the velocity distribution, (ii) The density decreases monotonously from the outside of the magneto-pause to the inside, (iii) The electrical current distribution is a typical current sheet structure, (iv) Under a certain condition of temperature parameters, the thickness of the magnetopause may be larger than the ion gyroradius. These results are applicable to the region of the low-latitude magnetopause during the intervals when the interplanetary magnetic field has a northward component.展开更多
基金supported by Start-up Funding Doctor of Xinjiang University(Grant No. BS090109)National Science Foundation of US (Grant No. DMS 0653881)National Natural Science Foundation of China (Grant No. 10871025)
文摘In this paper, the authors introduce a class of product anisotropic singular integral operators, whose kernels are adapted to the action of a pair A := (A1, A2) of expansive dilations on R n and R m , respectively. This class is a generalization of product singular integrals with convolution kernels introduced in the isotropic setting by Fefferman and Stein. The authors establish the boundedness of these operators in weighted Lebesgue and Hardy spaces with weights in product A∞ Muckenhoupt weights on R n × R m . These results are new even in the unweighted setting for product anisotropic Hardy spaces.
基金Project supported by the National Natural Science Foundation of China.
文摘A new magnetopause model is proposed based on observation results, in which the magnetic-field includes one constant component and one monotomcally increasing component, so that magnetic field shear exists during the intervals when the interplanetary magnetic field has a northward component. Under this model, a completely analytical self-consistent equilibrium distribution function is derived based on the Vlasov-Maxwell equations. Through the analysis of this distribution function and its moments, the following can be concluded: (i) The equilibrium distribution function consists of a homogeneous Maxwellian distribution and two inhomogeneous shifted-Maxwellian distributions. There are 'hole' and 'bump' structures which have different cross-field drift velocities in the velocity distribution, (ii) The density decreases monotonously from the outside of the magneto-pause to the inside, (iii) The electrical current distribution is a typical current sheet structure, (iv) Under a certain condition of temperature parameters, the thickness of the magnetopause may be larger than the ion gyroradius. These results are applicable to the region of the low-latitude magnetopause during the intervals when the interplanetary magnetic field has a northward component.
