Thesis (Ph. D.)--University of Chicago, 1916. / "A Private edition distributed by the University of Chicago Libraries." "Reprinted from the Physical review, n.s., vol. VIII, no. 4, October, 1916." Includes bibliographical references. Also available on the Internet.

[No abstract available] / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis describes the design and construction of an instrument for comparison of x-ray doses at two different points in an x-ray field. Essentially, it consists of two ionization chambers each fed into a very stable, linear, d.c. amplifier. The outputs of the d.c. amplifiers are coupled in such a way that a fraction of the output of one amplifier is balanced against the total output of the other in a ratio circuit. The scale of the ratio circuit may be set to read directly the dose at any point as a percentage of the dose at an arbitrarily chosen reference point. This percentage is independent of fluctuations of the x-ray intensity with time. The instrument is battery-operated, light in weight and therefore easily portable. The principal use of the instrument is for the comparison of x-ray doses at different points in a tissue-equivalent medium — information required for dose estimates in radiotherapy. The accuracy of the instrument is better than one half percent of the maximum dose in the x-ray field. The instrument can be modified for automatic plotting of "isodose curves". / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis deals with the current methods available for X-ray structure determination and with the crystal and molecular structure determination of five compounds using these methods. The five compounds are 1) [ 2,3-Bis (dimethylarsino)- 1, 1, 1,4, 4, 4-hexaf luorobut-2-ene-As,As]tricarbonyldiiodotungsten(II),Me₂AsC (CF₃):C (CF₃) AsMe₂WI₂(CO)₃ 2) Dimethylammonium trichlorotris(dimethylsulphoxide}-ruthenate(II) , [ ( (CE₃)₂ SQ)₃ RuCl₃ ]⁻ [ (CH₃)₂ NH ₂]+ 3) Dichlorotetrakis{dimethylsulphoxide)ruthenium(II), (Me₂SO)₄fRuCl₂ 4) 1,3,7-Triraethyl-2,6-dioxypuriae hydrochloride dihydrate (caffeine hydrochloride dihydrate), CH₁₁C1N₄0₂-2H₂0 .5) 1-Acetyl-3-benzamido-2-keto-4- (2,3, 4, 6-tetra-O-acetyl-β-D-glucopyranosyloxy)-Δ³-pyrroline, C ₂₇H₃₀N₂O₁₃ The structures of compounds 1), 2), and 3) were determined by Patterson syntheses, compound 4) by centrosymmetric direct methods and compound 5) by non-centrosymmetric direct methods. All structures were then refined using full-matrix least-sguares procedures. The relevant crystal data for all five compounds can be found in Table A In the tungsten compound [1) the tungsten atom is seven-coordinate with a distorted capped octahedral environment, the capping group being a carbonyl. The capped face consists of the two remaining carbonyl groups and one of the arsenic atoms from the bidentate ligand. The uncapped face contains the two iodine atoms and the remaining arsenic. Crystal data for the five compounds examined atom. The structure of the ruthenium compound [ 2) ] consists of two crystallcgraphically non-equivalent anions in the asymmetric unit linked by hydrogen bonding via dimethylammonium cations. The coordination geometry about the structurally similar anions is essentially that of an octahedron with the DHSO ligands being bonded to Ru via the sulphur atoms. The co-ordination geometry about the ruthenium atom for compound 3) is essentially octahedral with cis chlorine atoms; Of the four DMSO ligands three are S-bonded and one is O-bonded, the O-bonded ligand being trans to a S-bonded ligand. For caffeine hydrochloride [ 4) ] the fused ring system is essentially planar and protonated at the 9-positioh. The crystal contains two types of hydrogen bonding involving 0-H...C1 and N-H...0 interactions. The structure of compound 5) consists of a pyranose ring in the chair conformation with the four 0-acetyl substituents in equatorial positions; the pyranose ring is connected to a planar pyrroline ring via a β-oxygen bridge. / Science, Faculty of / Chemistry, Department of / Graduate

Call number: LD2668 .T4 1951 E38 / Master of Science

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Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

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