No abstract

No abstract

No abstract

No abstract

No abstract

We have observed four radicals in the ESR spectra of y-irradiated single crystals of some glutamic acid derivatives. These radicals, produced by gamma-irradiation, in single crystals of N-Acetyl-LGlutamic acid, L-Glutamic acid and DL-Glutamic acid hydrochloride were identified as CH3CONH, -C 3 H 5 , -CH. and -NH 2 radicals respectively.Free radicals produced by gamma irradiation in single crystals of N-Acetyl-L-Glutamic acid(l), LGlutamic acid (2) and DL-Glutamic acid hydrochloride (3) have been investigated between 100 and 350 K with ESR. The single crystal spectra have been taken at 5-degree intervals with the magnetic field B lying in each of the three crystallographic planes ab, be, and ca. Figure 1 shows the spectrum of 1 with its hyperFine splitting. In these spectra, 16-lines are observed due to CH3CONH and C3H5 radicals. Owing to the CH3CONH radical, the spectra exhibit an outer doublet (1:1) because of the proton directly attached to the nitrogen, and each of the outer lines splits into triplet lines (1:1:1) due to the nitrogen. Owing to the other allyl radical (C3H5) produced by gamma irradiation, inner 10-lines are also observed between these triplet lines. Inner doublet splittings are due to a-protons of the radical, then each line splits into Five lines (1:4:6:4:1) owing to the ^-protons of this radical. The proton splitting for the CH3CONH radical is about 8.9 mT, and the nitrogen splitting is approximately 0.8, 0.6, and 0.4 mT. The a and ß-proton splittings are approximately 3.4 and 0.6 mT, respectively. Such a result can arise if the unpaired electron interacts equally with the a-proton and to a somewhat lesser extent with four other equivalent ß-protons. The radical most likely formed in irradiated 1 which fits these requirements is the allyl radical (C3H5). The greater density of the electron at the nuclei of either a and ß protons farthest from the site of the unpaired electron can be accounted for in terms of conjugation. The

Low-temperature electron-impurity scattering times have been measured in n-type InSb samples with different electron densities from Faraday rotation by using a pulsed 0.337 mm HCN laser. The electron-impurity scattering times obtained from the experimental results using a curve-fitting method yielded values of 3 to 4*10-12 s at liquid helium temperatures for three different samples. These scattering times were in sharp contrast to the field dependent DC scattering times calculated from DC mobility measurements at 4.2K in zero magnetic field. However, there was good agreement between the impurity scattering times observed from the Faraday rotation measurements and those derived from the cyclotron resonance linewidth measurements at 4.2K. Possible explanations of the experimental results were also considered.

A grinding process that uses loose abrasives for the beveling of lenses is presented. Determination of the parameters of grinding tools with loose abrasives for beveling applications with various optical elements is discussed. The process of grinding with loose abrasives for a lapping operation is analyzed by examination of the influence of optical glass material parameters on material removal and surface roughness for lens manufacturing conditions. The model established for this analysis uses the concept of lateral fracture, which is based on removal of optical glass material by rolling abrasive particles. The particles remove material by lateral cracking. The abrasive mineral Barton Garnet was used in the lapping experiments. Under specific large-diameter lens manufacturing conditions, lapping time values at the conventional removal depth have been obtained for various optical glasses.