• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 356
  • 158
  • 58
  • 39
  • 7
  • 6
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • Tagged with
  • 740
  • 740
  • 145
  • 140
  • 82
  • 67
  • 67
  • 54
  • 53
  • 38
  • 37
  • 36
  • 36
  • 34
  • 34
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

A small angle X-ray scatterning study of water and [aqueous] LiOH solutions

Chonacky, Norman Joseph, January 1968 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.
92

A small angle X-ray scattering investigation of broad bean mottle virus

White, Richard Arnold. January 1963 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Abstracted in Dissertation abstracts, v. 23 (1963) no. 9, p. 3433. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 103-104).
93

X-ray diffraction studies of aqueous barium iodide solutions

Prince, A. Kelsey January 1956 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1956. / Typescript. Abstracted in Dissertation abstracts, v. 16 (1956) no. 11, p. 2042. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 64-65).
94

A general systems simulator and its application to a hospital x-ray department

Kartschoke, Robert P. January 1963 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 66).
95

The effects of 50 kilovolt x-rays on the alkali metal borohydrides

Walker, Leonard George January 1959 (has links)
The marked physical changes in potassium boro-hydride such as decrepitation and the development of a deep blue coloration when the solid compound is exposed to ionizing radiation stimulated a study of the effects of 50 Kvp X-rays on the alkali metal borohydrides to determine the nature of the radiation induced changes such as color center formation and chemical decomposition. Methods were developed to prepare the alkali metal borohydrides in a form suitable for radiation studies. Solvents studies showed that anhydrous hydrazine was an exceptionally good solvent for potassium borohydride, the solubility being 28.3 grams KBH₄ per 100 grams at 18.5° C. The handling of hydrazine as a solvent required the construction of special apparatus. A study of the use of hydrazine as a solvent for other ionic borohydrides and/or the growth of crystals suitable for spectroscopic work is incomplete. Therefore, the spectroscopic studies on radiation induced absorption bands was done mainly with thin pressed pellets. The borohydrides of rubidium and cesium were prepared by metathesis reactions from potassium borohydride via a sulfonium borohydride. The preparation of the previously unreported trimethylsulfonium borohydride is described. Color center formation was studied by spectroscopic methods only and the F and U type centers have been tentatively identified. The thermal stability and optical bleachability of some of the radiation induced absorption bands were examined. Chemical studies of radiation damage in potassium borohydride failed to show the presence of free alkali metal. Gaseous boron hydrides were also undetectable. Mass spectrometric examination of gaseous material evolved during irradiation showed only hydrogen to be present. No gas was evolved when heavily irradiated samples of potassium borohydride were dissolved in liquid ammonia. A discussion of methods and apparatus characteristic to the radiation studies such as the X-ray generator, radiation vessels, vacuum system, and a section on radiation dosimetry is included in the thesis. The intensity of X-rays generated by the Machlett OEG-60 X-ray tube was determined by the application of the included dosimetry data together with a calorimetric measurement of the output flux of the tube. At 50 Kvp and 28 milliamperes the intensity output was found to be 0.220 cal.min.⁻¹ cm.⁻² at the tube port. Some suggestions for further work are outlined at the end of the study. / Science, Faculty of / Chemistry, Department of / Graduate
96

The determination of the crystal structures of diferrocenyl ketone, anti-8-tricycle [3,2,1,O2,4] octyl p-bromobenzenesulphonate, anti-7-norbornenyl p-bromobenzoate and ochotensine methiodide

Macdonald, Alaistair Cumming January 1966 (has links)
The crystal structure of diferrocenyl ketone has been analyzed using Fe(Kα) X-radiation. The molecule is symmetrical about a 2-fold axis passing through the carbonyl bond. Coordinates of the iron atom were determined from two Patterson-Harker sections and coordinates of the remaining atoms were derived from subsequent three dimensional Fourier summations. Structure refinement was carried out using (block-diagonal) least squares with allowances for anisotropic temperature vibration. The R value derived from the final coordinates is 0.09. The cyclopentadienyl rings not bonded to the keto group are vibrating more than those which are; when this is taken into account the iron atom lies midway between the cyclopentadienyl rings which are planar and 3.30 Å apart. The carbon bond lengths in these rings are all the same length (1.45 Å) and the conformation of one ring with respect to the other is almost eclipsed. The intermolecular contacts are all of normal length. The molecular dimensions of anti-8-tricyclo [3,2,1,0²˒⁴] octyl p-bromobenzenesulphonate and anti-7-norborneny1 p-bromo-benzoate have been measured to assist in the interpretation of the solvolytic reactivity in norbornane derivatives. Data were collected (Cu(Kα) radiation) by counter methods in both cases; the structures were determined using the heavy atom-Patterson method and refinements were carried out using differential syntheses and (block-diagonal) least squares. The discrepancy factors derived from the final coordinates are 0.09 and 0.18 respectively. The norbornane and norbornene skeletons have symmetry m and the bond lengths are normal. The bond angles at the methylene bridge are 97° and 96° respectively, the other angles are all less than the tetrahedral angle. The angles between the planes formed by different parts of the skeleton are identical in both cases. Bond lengths and angles in the remainders of both molecules are of normal dimensions. The configuration of the cyclopropyl methylene group in anti-8- tricycle [3,2,1,0²˒⁴] octyl p-bromobenzenesulphonate is exo to the norbornane skeleton. The results indicate that there is insufficient variation in the methylene bridge bond angles to account for the difference in solvolytic reactivity. The crystal and molecular structure of ochotensine methiodide has been investigated in order to determine the chemical structure of the molecule. The data were recorded photographically using Cu(Kα) radiation and a Weissenberg equi-inclination camera; estimation of the intensities was carried out by visual methods and interfilm scales were derived from corresponding symmetry related structure amplitudes. 845 independent reflections were measured in this way. The position of the iodine atom was determined from a three dimensional Patterson function and the positions of the remaining atoms from three subsequent three-dimensional Fourier maps. Refinement of the temperature and atomic parameters was carried out by (block diagonal) least squares; the final R value was 0.11. The analysis has shown that the structure of ochotensine is similar to that postulated for ochotensimine and the position of the phenolic group on ring A has been determined. A difference synthesis was carried out to verify the positions of the atoms. The bond lengths and angles are normal but several short intermolecular contacts were observed. The planes of the two benzene rings are inclined at an angle of 94°. / Science, Faculty of / Chemistry, Department of / Graduate
97

Low temperature x-ray diffraction studies of TaS₂ and LixTiS₂

Dutcher, John Robert January 1985 (has links)
A low temperature x-ray powder diffraction attachment for use on the vertical goniometer of a diffractometer is described. We have found that diffraction patterns obtained with the attachment mounted on the goniometer are of comparable quality to those obtained on the goniometer itself. Using this attachment, the lattice parameter discontinuities associated with a charge density wave phase transition in 1T-TaS₂ near T=200K are measured with an accuracy greater than that of any previous results. Electrochemically prepared samples of Li xTiS₂ near x=0.16 are studied at room temperature and below. Clear evidence for the formation of a stage two superlattice at low temperatures was not obtained. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
98

A study of the distribution of diffracted intensity in reciprocal space for franckeite-type minerals /

Trudeau, Marc. January 1975 (has links)
No description available.
99

A neutron and x-ray diffraction determination of the structure and amplitudes of thermal motion in crystalline aluminum chloride hexahydrate /

Buchanan, David Royal January 1962 (has links)
No description available.
100

The effects of total-body irradiation with x-rays and supplementary injections of liver homogenate upon the survival period in inbred lines of the syrian hamster, Mesocricetus auratus (waterhouse) /

Skavaril, Russell V. January 1964 (has links)
No description available.

Page generated in 0.1109 seconds