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Low Annealing Temperature (low + annealing_temperature)
Selected AbstractsDetermination of genomic damage in neuroblastic tumors by arbitrarily primed PCR: MYCN amplification as a marker for genomic instability in neuroblastomasNEUROPATHOLOGY, Issue 3 2006Jorge Muñoz The aim of this study is to establish an estimation of the global genomic alteration in neuroblastic tumors (ganglioneuromas, ganglioneuroblastomas and neuroblastomas) and correlate them with different clinical parameters (age, sex, diagnosis, Shimada index, proliferation index, tumor location, and 1p and v-myc avian myelocitomatosis viral-related (MYCN) status) in order to find new molecular and/or prognostic markers for neuroblastoma. To assess the genomic damage in neuroblastic tumors, we used an arbitrarily primed PCR approach, a technique based on the reproducibility of band profiles obtained by a PCR with a low annealing temperature in its first cycles. Genomic damage was assessed by comparing band profiles of tumors and normal paired samples. Gains and losses in the intensity of the bands were computerized and referred to the total number of bands analyzed. We found a higher genomic damage fraction (GDF) in the female's group (U-Mann,Whitney, P = 0.025), but we could not find any association between GDF and tumor location, proliferation index, diagnosis or age of the patient. There was no relationship between 1p status and GDF, but tumors with MYCN amplification had a slightly higher GDF. MYCN amplification might in some way contribute to genomic instability of neuroblastomas. [source] Temperature Dependence of the Formation of Graphene and Subsurface Carbon on Ru(0001) and Its Effect on Surface ReactivityCHEMPHYSCHEM, Issue 5 2010Yi Cui Switching the surface structure: The formation of graphene and subsurface carbon on Ru(0001) is controlled by regulating the annealing temperature (see picture). A low annealing temperature (LT) drives bulk dissolved carbon onto the surface to form graphene. At high temperatures (HT), surface graphene carbon can diffuse into the subsurface or move into the bulk of the metal. [source] Photophysics and Photocurrent Generation in Polythiophene/Polyfluorene Copolymer BlendsADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Christopher R. McNeill Abstract Here, studies on the evolution of photophysics and device performance with annealing of blends of poly(3-hexylthiophene) with the two polyfluorene copolymers poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2,,2,,-diyl) (F8TBT) and poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) are reported. In blends with F8TBT, P3HT is found to reorganize at low annealing temperatures (100,°C or below), evidenced by a redshift of both absorption and photoluminescence (PL), and by a decrease in PL lifetime. Annealing to 140,°C, however, is found to optimize device performance, accompanied by an increase in PL efficiency and lifetime. Grazing-incidence small-angle X-ray scattering is also performed to study the evolution in film nanomorphology with annealing, with the 140,°C-annealed film showing enhanced phase separation. It is concluded that reorganization of P3HT alone is not sufficient to optimize device performance but must also be accompanied by a coarsening of the morphology to promote charge separation. The shape of the photocurrent action spectra of P3HT:F8TBT devices is also studied, aided by optical modeling of the absorption spectrum of the blend in a device structure. Changes in the shape of the photocurrent action spectra with annealing are observed, and these are attributed to changes in the relative contribution of each polymer to photocurrent as morphology and polymer conformation evolve. In particular, in as-spun films from xylene, photocurrent is preferentially generated from ordered P3HT segments attributed to the increased charge separation efficiency in ordered P3HT compared to disordered P3HT. For optimized devices, photocurrent is efficiently generated from both P3HT and F8TBT. In contrast to blends with F8TBT, P3HT is only found to reorganize in blends with F8BT at annealing temperatures of over 200,°C. The low efficiency of the P3HT:F8BT system can then be attributed to poor charge generation and separation efficiencies that result from the failure of P3HT to reorganize. [source] Microstructure Development in Unsupported Thin FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2002Brian P. Gorman To better understand the role of the substrate in the microstructural evolution of thin films, unsupported nanocrystalline yttrium-stabilized zirconia (ZrO2:16%Y or YSZ) films were examined as a function of temperature and annealing time. Grain growth, texturing, and pinhole formation were measured using transmission electron microscopy (TEM) and electron diffraction. Films were produced and subsequently annealed on metallic grids using a previously developed technique that results in near full density films at low annealing temperatures. Microstructural evolution in these films was unique compared with constrained films. Grains were found to spheroidize much more readily, ultimately resulting in the formation of porosity and pinholes. Grain growth was found to stagnate at a size particular to each annealing temperature, presumably due to the effects of Zener pinning. It is proposed that the lack of substrate strain and confinement effects allows for the dominance of surface energetics with respect to microstructural evolution. [source] | ||||||||||