Global ETD Search

271	Low energy electron diffraction from SI(111)7X7 and ultrathin films onsubstrate crystals Lai, Wai-kong, Pan., 黎偉江. January 1999 (has links) published_or_final_version / Physics / Master / Master of Philosophy Low energy electron diffraction. Thin films. Crystals.
272	Surface structure determination by Patterson inversion of multi-incidence LEED IV-curves Ma, King-man, Simon., 馬勁民. January 2001 (has links) published_or_final_version / Physics / Master / Master of Philosophy Crystals - Surfaces. Low energy electron diffraction.
273	THE LUNAR LASER RANGING POINTING PROBLEM Carter, William E. (William Eugene), 1939- January 1973 (has links) No description available. Lunar laser ranging. Laser beams -- Diffraction.
274	A COMPARISON OF CODED APERTURE IMAGING SYSTEMS CONTAINING ZONE PLATE AND RANDOM-PHASE CODE FUNCTIONS Whitehead, Frank Roger, 1944- January 1976 (has links) No description available. Diffraction. Image intensifiers. Radiography -- Image quality.
275	An X-ray study of silver iodide Nichols, Monte C., 1938- January 1962 (has links) No description available. Silver halides -- Analysis. X-rays -- Diffraction.
276	Optimization of periodic devices using the finite element method Khalaf, Loay D. 12 1900 (has links) No description available. Diffraction gratings Electromagnetic theory Finite element method
277	Electromagnetic diffraction by a planar array of dielectric cylinders. Barkley, Lorne. January 1971 (has links) No description available. Electromagnetic theory Diffraction Dielectrics Cylinders Scattering (Physics)
278	A powder diffraction study of problems in platinum group metal extraction. Smith, Ian William Sands. January 1994 (has links) The base metal and platinum group metal extractive processes for two South African refineries were examined using x-ray powder diffraction. Base metal refinery matte contained nickel sulphide (Ni3S2), copper sulphide (Cu2S), nickel-copper alloy (Ni-Cu), iron oxide (Fe3O4) - nickel iron oxide (NiFe2O4) and nickel oxide (NiO). Nickel iron oxide and cobalt sulphide (CO3S4) were found in matte aeration cavities. Matte fast cooling caused alloy zoning. Alloy stoichiometry and weight percentages of matte constituents were calculated. Magnetic separation of the alloy phase was unfeasible due to high bulk and poor separation from Ni3S2. Sulphuric acid matte leaching produced residues containing copper sulphide (Cul.8S) and nickel sulphides (Ni3S4, NiS). Potassium cyanide residue leaching produced NiS-rich residues, while thiourea / hydrochloric acid leaching produced residues almost free of copper sulphide. PGM concentrates were examined. Base metals occurred as: copper sulphate pentahydrate; copper sulphate hydroxide hydrate (CU4SO4(OH)6'H2O); copper sulphide (CuS); copper platinum (Cu3Pt); nickel oxide (NiO); nickel iron oxide (NiFe2O4). Lead occurred as lead sulphate and silicon as quartz and enstatite ((Mg,Fe,Al)SiO3). Heating the concentrate to 260°C with sulphuric acid converted copper sulphide to copper sulphate. PGMs were mostly metallic. Overdrying concentrates caused pgm sintering. Drying with sulphuric acid reduced sintering. PGM oxidative leach solubility was examined. Platinum sulphide (Pt,Pd)S caused low platinum and palladium solubility. (Ru,Rh,Ir,Pt)AsS caused low rhodium and ruthenium solubility. Platinum-rhodium (Rh0.57Pt0.43), ruthenium-osmium (~Ru16Os), iridosmine (Os,Ir,Ru) also caused low pgm solubility. Silver chloride remained in residues. Concentrate overdrying produced insoluble sintered platinum, palladium monoxide, and ruthenium dioxide. In minor concentrates sintered platinum, rhodium selenide (RhSe2+x), ruthenium dioxide and possibly palladium monoxide lowered pgm solubility. Precipitates and salts were examined. Iron precipitated as iron oxide hydroxide (B-FeOOH); gold as metallic gold; lead as lead chloride. Common salts were: sodium chloride; sodium iron hydroxide sulphate hydrate (Na2Fe(SO4)2(OH)'3H2O); ammonium chloride; sodium carbonate monohydrate. PGM-Iead fusion was examined. Fusion produced the insoluble alloy Pb(Pd,Pt)3. Ruthenium dioxide reacted with lead carbonate forming lead ruthenium oxide (Pb2Ru2O6.5). Nitric acid insoluble residues also contained lead sulphate and iron oxide (Fe3O4). This study demonstrated that solution problems can be understood by identifying the crystalline insoluble phases in intractable residues. / Thesis (Ph.D.)-University of Natal, Durban, 1994. X-Rays--Diffraction. Platinum group. Theses--Chemistry.
279	Crystal study of Zr[subscript]0# [subscript]812Y[subscript]0# [subscript]188O[subscript]1# [subscript]91 and CeO[subscript]2 by x-ray powder diffraction and a computer pattern-fitting technique Hann, Raiford Eugene 12 1900 (has links) No description available. Crystallography Cerium oxides X-rays Diffraction
280	High efficiency volume grating coupler Schultz, Stephen M. 08 1900 (has links) No description available. Integrated optics Diffraction gratings Optical wave guides

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