ABSTRACT
This study reports the synthesis of GaN nanoparticles having hexagonal structure by a simple technique of activated reactive evaporation with substrates kept at comparatively lower temperatures than usually reported. By varying the substrate temperature from 30 degrees C to 350 degrees C, it is possible to vary nanoparticle sizes from 5-30 nm. X-ray diffraction and X-ray photoelectron spectroscopy analysis confirm the formation of GaN on quartz and silicon substrates at room temperature. The observed size dependent shift in energy position, large increase in full width at half maximum value of Ga 3d and N 1s X-ray photoelectron spectroscopy peaks and blue shift in the optical absorption edge are related to nanoparticle character.
Subject(s)
Gallium/chemistry , Nanostructures/chemistry , Spectrometry, X-Ray Emission/methods , Microscopy, Electron, Transmission , Nanotechnology/methods , Nanotubes , Particle Size , Quartz/chemistry , Silicon/chemistry , Surface Properties , Temperature , X-Ray Diffraction , X-RaysABSTRACT
16 cases of hemoglobin E-thalassemia are reported. The interaction of thalassemia with Hb E produced a varying severity of E-thalassemia. 10 cases had a thalassemia intermedia type of clinical picture while 6 had a more severe disorder requiring regular transfusions from early childhood. 14 patients were producing Hb-A and therefore had beta+ type thalassemia whereas 1 case had no Hb-A because of beta 0 type thalassemia. This is in contrast to a much higher frequency of beta 0 thalassemia in cases reported from South-East Asia. Family studies in 1 patient revealed the interaction with delta-beta thalassemia, a situation which is rare. Mating of an Hb E-thalassemia subject with heterozygous beta thalassemia resulted in an offspring with severe homozygous thalassemia.
