Due to their sinusoidal groove profile, holographic gratings cannot be easily blazed and their efficiency is usually considerably less than a comparable ruled grating.
2.
The concept of a coarsely-ruled grating used at grazing angles was discovered by Albert Michelson in 1898, where he referred to it as an " echelon ".
3.
But the rules grated against new issues in the Internet age : how to regulate public access computers to block now-banned games but permit legal uses such as chat rooms or e-mail?
4.
But the rules grate against new issues in the Internet age : how to regulate public access computers to block now-banned games such as Mah Jong Solitaire but permit legal uses such as chat rooms or e-mail?
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