Westinghouse Electric

About: Westinghouse Electric is a company organization based out in Cranberry Township, Pennsylvania, United States. It is known for research contribution in the topics: Brake & Circuit breaker. The organization has 27959 authors who have published 38036 publications receiving 523387 citations.

Raman Scattering by Silicon and Germanium

Abstract: Raman scattering from single-crystal Si and Ge at 300\ifmmode^\circ\else\textdegree\fi{}K was measured using an argon laser as the exciting source The first-order Raman spectrum yields energies for the $k\ensuremath{\approx}0$ optical modes of 5202\ifmmode\pm\else\textpm\fi{}05 ${\mathrm{cm}}^{\ensuremath{-}1}$ for Si and 3007\ifmmode\pm\else\textpm\fi{}05 ${\mathrm{cm}}^{\ensuremath{-}1}$ for Ge These values are in reasonable agreement with other determinations The full widths at half-intensity were found to be 46 ${\mathrm{cm}}^{\ensuremath{-}1}$ for Si and 53 ${\mathrm{cm}}^{\ensuremath{-}1}$ for Ge These values are compared with theoretical predictions A Raman band was observed in Si at 950 ${\mathrm{cm}}^{\ensuremath{-}1}$ which is attributed to second-order scattering and is compared with theoretical predictions

Thermal Resistance due to Point Defects at High Temperatures

Abstract: An expression is obtained for the lattice thermal conductivity at high temperatures in the limit when the scattering of phonons by point defects is stronger than by umklapp processes. The latter limit the phonon mean free path at low frequencies and most of the heat is transported at frequencies such that the point defect and umklapp mean free paths are equal. The conductivity varies as ${(\mathrm{AT})}^{\ensuremath{-}\frac{1}{2}}$, where $A$ is proportional to the strength of the point defect scattering, $T$ is the temperature. The theory is in rough agreement with the thermal conductivity of Ge-Si alloys, measured by Steele and Rosi.

The interaction of a crack front with a second-phase dispersion

Abstract: Observations are presented showing that a crack front increases its length by changing its shape when it interacts with two or more inhomogeneities in a brittle material. These observations are presented for both cleavage and conchoidal types of fracture. Based on these observations and the concept that a crack front possesses a line energy, an expression for the fracture energy is obtained. This expression shows that the fracture energy should increase as the distance between the dispersed inhomogeneities is decreased. Using the Griffith fracture criterion, this result is discussed for the case of strengthening a brittle material.

Evaluation of antenna Q

Abstract: A method is presented for evaluating the Q of an antenna, where the Q is defined as in conventional network theory. The method consists of subtracting the energy density associated with the power flow from the total energy density, thus enabling the magnetic and electric reactive energy to be computed. Specific application of the method is made to the evaluation of the Q of spherical and cylindrical modes. It is verified that the Q becomes very large when the order of the mode exceeds k_{0}a where a is the radius of the sphere or cylinder on which the sources are located.