Plasma-maser instability of the ion acoustics wave in the presence of lower hybrid wave turbulence in inhomogeneous plasma

A theoretical study is made on the generation mechanism of ion acoustics wave in the presence of lower hybrid wave turbulence field in inhomogeneous plasma on the basis of plasma-maser interaction. The lower hybrid wave turbulence field is taken as the low-frequency turbulence field. The growth rate of test high frequency ion acoustics wave is obtained with the involvement of spatial density gradient parameter. A comparative study of the role of density gradient for the generation of ion acoustics wave on the basis of plasma-maser effect is presented. It is found that the density gradient influences the growth rate of ion acoustics wave.     

Convergence properties of Beale-Powell restart algorithm

The Beale-Powell restart algorithm is highly useful for large-scale unconstrained optimization. An example is taken to show that the algorithm may fail to converge. The global convergence of a slightly modified algorithm is proved. Project partially supported by the National Natural Science Foundation of China.     

Mössbauer Studies on Nanocrystalline Diol Capped γ-Fe2O3

Nanocrystalline indium (nano-In) was prepared with different particle sizes by electrochemical deposition. The temperature dependence of the local electric field gradient (EFG) of nano-In was investigated in a temperature range of 20–300 K using the probe ¹¹¹In for perturbed γγ angular correlation (PAC) experiments. The temperature dependence of the EFG of nano-In can be described by a (1−BT ^3/2) dependence as in bulk-In. It is shown that the low temperature value of the EFG and the proportionality constant B vary systematically with particle size.     

一类无充分下降条件的非单调共轭梯度法的全局收敛性分析

In [3] Liu et al. investigated global convergence of conjugate gradient methods.In that paper they allowed βk to be selected in a wider range and the global convergence of the corresponding algorithm without sufficient decrease condition was proved. This paper investigates global convergence of nonmonotone conjugate gradient method under the same conditions.     

仿射内点既约投影Hessian算法解非线性约束优化

本文结合非单调内点回代技术,提供了新的仿射信赖域方法解含有非负变量约束和非线性等式约束的优化问题.为求解大规模问题,采用等式约束的Jacobian矩阵的QR分解和两块校正的双边既约Hessian矩阵投影,将问题分解成零空间和值空间两个信赖域子问题.零空间的子问题为通常二次目标函数只带椭球约束的信赖域子问题,而值空间的子问题使用满足信赖域约束参数的值空间投影向量方向.通过引入Fletcher罚函数作为势函数,将由两个子问题结合信赖域策略构成的合成方向,并使用非单调线搜索技术回代于可接受的非负约束内点步长.在合理的条件下,算法具有整体收敛性且两块校正的双边既约Hessian投影法将保持超线性收敛速率.非单调技术将克服高度非线性情况,加快收敛进展.     

自聚焦透镜光斑直径,分辨率测试研究

通过显微镜放大、ＣＣＤ图像接收采集、计算机数据处理技术来测量自聚焦透镜（ＧＲＩＮ透镜）光斑直径、分辨率。重点对误差进行分析。通过对样品５２０－０２５－０８３的测试，表明该系统光斑直径、分辨率测试不确定度优于±０．１μｍ及１％，与误差分析相吻合。     

A conjugate gradient method for the unconstrained minimization of strictly convex quadratic splines

In this paper, we show that an analogue of the classical conjugate gradient method converges linearly when applied to solving the problem of unconstrained minimization of a strictly convex quadratic spline. Since a strictly convex quadratic program with simple bound constraints can be reformulated as unconstrained minimization of a strictly convex quadratic spline, the conjugate gradient method is used to solve the unconstrained reformulation and find the solution of the original quadratic program. In particular, if the solution of the original quadratic program is nondegenerate, then the conjugate gradient method finds the solution in a finite number of iterations. This author's research is partially supported by the NASA/Langley Research Center under grant NCC-1-68 Supplement-15.     

A new approach for heavy ion fusion spin distribution

The method of optical model analysis of generalized elastic scattering angular distributions (GESA) has been applied to heavy ion scattering to derive fusion spin distributions. This method is used to reproduce the coupled channel fusion spin distributions. When applied to experimental data, particularly to the fissile systems like¹⁶O +²³²Th, the method gives large mean square spin values in agreement with “anomalous” values derived from experimental fission fragment anisotropies.     

求解带状线性方程组的并行分割算法

讨论了求解带状线性方程组的并行分割算法．对影响算法并行效率的约化方程组采取了在多台处理机上重复求解的方法，减少了数据的通信次数，提高了算法的并行效率．算法在一些新的并行计算机系统上使用，达到高并行效率．