tailieunhanh - Volume 10 - Materials Characterization Part 15

Tham khảo tài liệu 'volume 10 - materials characterization part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Glossary of Terms o A z aberration In microscopy any error that results in image degradation. Such errors may be chroma-spherical astigmatic comatic distortion or curvature of field and can result from design I execution or both. z absorbance The logarithm to the base 10 of the reciprocal of the transmittance. The preferred term 1 photography is optical density. z absorption of electromagnetic radiation A decrease in the intensity of the beam light x-rays electrons and so on when passing thro matter. In many cases specific wavelengths or energies are preferentially absorbed forming basis of absorption spectroscopy. z absorption contrast In transmission electron microscopy image contrast caused by differences in absorption withi sample due to regions of different mass density and thickness. z absorption edge wavelength or energy corresponding to a discontinuity in the plot of absorption coefficient vers wavelength for a specific medium. z absorption spectroscopy The branch of spectroscopy treating the theory interpretation and application of spec originating in the absorption of electromagnetic radiation by atoms ions radicals and moleculf z absorptivity A measure of radiant energy from an incident beam as it traverses an absorbing medium equi the absorbance of the medium divided by the product of the concentration of the substance the sample path length. Also known as absorption coefficient. z accelerating voltage In various electron beam instruments and x-ray generators the difference in potential between filament cathode and the anode causing acceleration of the electrons by 2 to 30 keV. See depth of penetration resolution . z accuracy The degree of agreement of a measured value with the true or correct value for the quantity bi measured. z achromatic Refers to an optical element that transmits light without dispersing it into its componer wavelengths. See also achromatic lens apochromatic lens . z achromatic lens A lens that is corrected for chromatic aberration