The diffraction efficiency behavior of reflection gratings with an asymmetrical trapezoidal groove profile has been studied. Theoretical calculations predict that at certain grating parameters superior efficiency compared to the conventional ruled gratings can be achieved.

efficiency calculations for units belonging to one group according to data envelopment analysis widely have received attention; while experiences related to efficiency comparison of several groups consisted of decision making units is restricted. kao's parallel system network dea model that has been designated aimed at such a comparison, practically leads to accomplish comparison among uni...

Efficient mode shape extraction of fluid-structure systems is of particular interest in engineering. An efficient modified version of unsymmetric Lanczos method is proposed in this paper. The original unsymmetric Lanczos method was applied to general form of unsymmetric matrices, while the proposed method is developed particularly for the fluid-structure matrices. The method provides us with si...

Daubechies wavelets are a powerful systematic basis set for electronic structure calculations because they are orthogonal and localized both in real and Fourier space. We describe in detail how this basis set can be used to obtain a highly efficient and accurate method for density functional electronic structure calculations. An implementation of this method is available in the ABINIT free soft...

This paper presents investigative results of the energy efficiency of hot water production for sanitary uses by means of gas-fired water heaters with the combustion chamber sealed with respect to the room in single-family houses and multi-story buildings. Additionally, calculations were made of the influence of pre-heating the air for combustion in the chimney and air supply system on the energ...