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Live rats resulting from injection of oocytes with spermatozoa freeze-dried and stored for one year
ArticleMolecular Reproduction and Development. 75(5): 890-894 (2008)journal articl
High Precision CTE-Measurement of SiC-100 for Cryogenic Space-Telescopes
We present the results of high precision measurements of the thermal
expansion of the sintered SiC, SiC-100, intended for use in cryogenic
space-telescopes, in which minimization of thermal deformation of the mirror is
critical and precise information of the thermal expansion is needed for the
telescope design. The temperature range of the measurements extends from room
temperature down to 10 K. Three samples, #1, #2, and #3 were
manufactured from blocks of SiC produced in different lots. The thermal
expansion of the samples was measured with a cryogenic dilatometer, consisting
of a laser interferometer, a cryostat, and a mechanical cooler. The typical
thermal expansion curve is presented using the 8th order polynomial of the
temperature. For the three samples, the coefficients of thermal expansion
(CTE), \bar{\alpha}_{#1}, \bar{\alpha}_{#2}, and \bar{\alpha}_{#3} were
derived for temperatures between 293 K and 10 K. The average and the dispersion
(1 rms) of these three CTEs are 0.816 and 0.002 (/K),
respectively. No significant difference was detected in the CTE of the three
samples from the different lots. Neither inhomogeneity nor anisotropy of the
CTE was observed. Based on the obtained CTE dispersion, we performed an
finite-element-method (FEM) analysis of the thermal deformation of a 3.5 m
diameter cryogenic mirror made of six SiC-100 segments. It was shown that the
present CTE measurement has a sufficient accuracy well enough for the design of
the 3.5 m cryogenic infrared telescope mission, the Space Infrared telescope
for Cosmology and Astrophysics (SPICA).Comment: in press, PASP. 21 pages, 4 figure
Constitution of the Indium-Rich Portion of the Indium-Magnesium System
The equilibrium phase diagram of the indium-magnesium system in the range up to 40 at.% Mg has been established by X-ray diffraction and thermal analysis. The solid-solubility of magnesium in indium does not exceed about 5 at.%. An intermediate solid solution, γ, with a face-centered cubic structure exists over a wide range of composition. An ordered phase, γ\u27, with superstructure of Cu_3Au-type, is formed near 28 at.% Mg at temperatures below 114℃. The axial ratio c/a of the primary solid solution of indium in magnesium changes as a function of electron/atom ratio as in the parallel case of the indium-cadmium system. Reasons are advanced to explain the conflict between the present results and those of earlier investigators
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