Abstract: In an HEMT, a channel forming layer is arranged above a semi-insulating substrate via a buffer layer. A spacer layer is arranged on the channel forming layer and an electron supplying layer and a Schottky contact layer are sequentially arranged on the spacer layer. A diffusion preventing layer, for preventing a metal element of a gate electrode from diffusing into the channel forming layer, is arranged in the Schottky contact layer.

Abstract: A reflector which is formed of three or more of reflector modules (called stacks) arranged in arrays and bonded to each other, the stacks being arranged to average the distribution of thermal deformations thereof in terms of inhomogeneity among the stacks in average coefficient of linear expansion, thereby suppressing deformation and deterioration of image-forming performance quality of the reflector under varying temperature conditions. The stacks are arranged in order of the magnitude of values of average coefficients of linear expansion possessed by said stacks so that a thermal deformation pattern produced is a relatively simple pattern, there is provided a reflector device in which correction of thermal deformation can be made by a few actuators.

Abstract: Described herein is a reflector which is formed of three or more of reflector modules (called stacks in followings) arranged in arrays and bonded to each other the stacks being arranged to average the distribution of thermal deformations thereof in terms of inhomogeneity among the stacks in average coefficient of linear expansion, thereby suppressing deformation and deterioration of image-forming performance quality of the reflector under varying temperature conditions. Since the stacks are arranged in order of the magnitude of values of average coefficients of linear expansion possessed by said stacks so that a thermal deformation pattern produced is a relatively simple pattern, there is provided a reflector device in which correction of thermal deformation can be made by a few actuators.

Abstract: A reflecting mirror, wherein mirror segments are fused together thereby composing the reflecting mirror by formulating square sums of displacements at a plurality of sampling points on a mirror surface of the reflecting mirror as a function of a thermal expansion coefficient vector having components of deviations of thermal expansion coefficients of the respective mirror segments from the average thermal expansion coefficients of all the mirror segments, positions of the components corresponding to arranging positions of the respective mirror segments; generating a stochastic process wherein the smaller the square sum of the displacement of the thermal expansion coefficient vector, the larger the probability whereby the thermal expansion coefficient vector appears, by a computer using random numbers; selecting the thermal expansion coefficient vector minimizing the square sum of the displacement from the appeared thermal expansion coefficient vectors; and arranging and fusing together the mirror segments in a

Abstract: A method of fabricating a reflecting mirror, wherein mirror segments are fused together thereby composing the reflecting mirror comprising, formulating square sums of displacements at a plurality of sampling points on a mirror surface of the reflecting mirror as a function of a thermal expansion coefficient-vector having components of deviations of thermal expansion coefficients of the respective mirror segments from the average thermal expansion coefficients of all the mirror segments, positions of the components corresponding to arranging positions of the respective mirror segments; generating a stochastic process wherein the smaller the square sum of the displacement of the thermal expansion coefficient vector, the larger the probability whereby the thermal expansion coefficient vector appears, by a computer using random numbers; selecting the thermal expansion coefficient vector minimizing the square sum of the displacement from the appeared thermal expansion coefficient vectors; and arranging and fusing

Abstract: The present invention relates to a method of fabricating a reflection mirror formed by sticking together a plurality of mirror segments for use on a reflecting telescope or the like. The mirror segments are arranged so that the thermal deformation of the reflecting mirror is limited to the least possible extent. The method comprises steps of: setting a plurality of sample points on the mirror surface; developing a matrix connecting a coefficient of the thermal expansion (CTE) vector having the deviations of the respective CTEs of the mirror segments from the average CTEs obtained by averaging the CTEs of the mirror segments as components corresponding to the respective positions of the mirror segments with the displacements of the sample points; selecting a vector making the sum of squares of the displacements a minimum among those obtained by rearranging the components of the CTE vector; and arranging the mirror segments according to the positions of the components of the selected vector.

Abstract: Described herein is a reflector which is formed of three or more of reflector modules (called stacks in followings) arranged in arrays and bonded to each other the stacks being arranged to average the distribution of thermal deformations thereof in terms of inhomogeneity among the stacks in average coefficient of linear expansion, thereby suppressing deformation and deterioration of image-forming performance quality of the reflector under varying temperature conditions. Since the stacks are arranged in order of the magnitude of values of average coefficients of linear expansion possessed by said stacks so that a thermal deformation pattern produced is a relatively simple pattern, there is provided a reflector device in which correction of thermal deformation can be made by a few actuators.