The best and most detailed structural information is obtained when the diffraction pattern of a single crystal a few tenths of a millimetre in each dimension is analyzed, but growing high-quality crystals of this size is often difficult, sometimes impossible. However, many crystallization experiments that do not yield single crystals do yield showers of randomly oriented microcrystals that can ...

abstract wenner direct contact method is a method of estimating apparent electrical conductivity (eca) of agricultural soils in situ. this method can be affected by factors such as quality of electrodes in contact with soil, type of employed electric current, moisture content, clay content and compaction of soil. in this research, the effect of electrode type (rod and plate) and electric curren...

In this paper, the direct method is utilized for solving second order two-point boundary value problem of Neumann type. The method will obtain the solution of the second order boundary value problem directly without reducing it to to first order equations. The method will be implemented using variable step size via shooting technique adapted with the Newton method. Numerical results are given t...

technical efficiency of different sectors is important for economic policy making purposes. this study considering regions as independent decision-making units, measures technical efficiency of industrial sector for every region of the country and then examines its determinant factors.generally influential factors of efficiency are classified in two main groups. first group includes the basic e...

We study methods for the numerical solution of the Helmholtz equation for twodimensional applications in geophysics. The common framework of the iterative methods in our study is a combination of an inner iteration with a geometric multigrid method used as a preconditioner and an outer iteration with a Krylov subspace method. The preconditioning system is based on either a pure or shifted Helmh...

We develop a general method for computing extreme value distribution (Gumbel, 1958) parameters for gapped alignments. Our approach uses mixture distribution theory to obtain associated BLOSUM matrices for gapped alignments, which in turn are used for determining significance of gapped alignment scores for pairs of biological sequences. We compare our results with parameters already obtained in ...

This paper establishes a direct method for solving variational problems via a set of Radial basis functions (RBFs) with Gauss-Chebyshev collocation centers. The method consist of reducing a variational problem into a mathematical programming problem. The authors use some optimization techniques to solve the reduced problem. Accuracy and stability of the multiquadric, Gaussian and inverse multiq...

Nanocrystalline ZnO particles were prepared by a novel sonochemical route from zinc acetate and sodium hydroxide without any requirement of calcination steps at high temperature and without surfactants. Variations in several parameters and their effects on the structural (crystal size and morphology) properties of nanoparticles were investigated. Characterizations were carried out by X-Ray ...

nanocrystalline zno particles were prepared by a novel sonochemical route from zinc acetate and sodium hydroxide without any requirement of calcination steps at high temperature and without surfactants. variations in several parameters and their effects on the structural (crystal size and morphology) properties of nanoparticles were investigated. characterizations were carried out by x-ray diff...