Capacitance spectroscopy of alumina sol-gel capacitors with Al top contacts

We measured the complex capacitance C(f) of ITO/sol-gel alumina/Al capacitors deposited on glass (and some on stainless steel foil) in the frequency range 15 Hz-10 MHz. The sol-gel films were deposited by dip-coating and following a two-step process. The capacitance C(f) found was much higher than that of a pure Al2O3-film due to the remaining porosity of the film and the uptake of H2O from the environment. The C(f) curves are useful as a sensitive probe for the porosity of the sol-gel film. In particular the evolution of the capacitance curve with time after drying has been measured. The curves can qualitatively be understood by modelling the capacitor as a (nearly) percolating random insulator/conductor network, using the effective medium approximation. However a detailed understanding of the relation between the C(f,t) curves and the structure of the films requires a more elaborate model. Films sintered at 500-550 degrees C for 1 h initially behave exactly as not sintered films but in contrast with the latter they improve slowly over time. Fast sintering yields better films

Atomic layer deposition of ZnO thin films on boron-doped nanocrystalline diamond

ZnO thin films were successfully prepared on boron-doped nanocrystalline diamond NCD by means of atomic layer chemical vapour deposition. Their growth and properties are similar to the layers grown by the same technique on glass. The layers thickness can be easily monitored by the number of precursors pulses. The ZnO layers are uniform and have perfect adhesion to NCD. Electrical measurements show that there is no current rectification if highly doped NCD and low resistance ALCVD ZnO are used. On the contrary, a rectifying behaviour can be obtained if lightly boron-doped NCD and resistive hydrothermally prepared ZnO are used

Validation of prediction models for near adult height in children with idiopathic growth hormone deficiency treated with growth hormone: A belgian registry study

Background/Aim: To validate prediction models for near final adult height (nFAH) by Ranke et al. [Horm Res Paediatr 2013;79:51-67]. Methods: Height data of 127 (82 male) idiopathic growth hormone (GH)-deficient children, treated with GH until nFAH, were retrieved from the database of the Belgian Society for Pediatric Endocrinology and Diabetology (BESPEED). nFAH was predicted after first-year GH treatment, applying prediction models by Ranke et al. Bland-Altman plots and Clarke error grid analyses were performed to assess clinical significance of the differences between observed and predicted nFAH. Results: In males, the predicted nFAH was higher than the observed nFAH (difference: 0.2 ± 0.7 SD; p < 0.01). In females, there was no significant difference. Bland-Altman analyses showed that the means of the differences between observed and predicted nFAH were close but not equal to zero, with overprediction for smaller heights and underprediction for taller heights. Clarke error grid analysis: in males, 59-61% of the predicted nFAH were within 0.5 SDS and 88% within 1.0 SDS from the observed nFAH; in females, 40-44% of the predicted nFAH were within 0.5 SDS and 76-78% within 1.0 SDS from the observed nFAH. Conclusion: Ranke's models accurately predicted nFAH in females and overpredicted nFAH in males by about 1.5 cm. In most individuals, the predicted nFAH was within 1 SDS of observed nFAH. These models can be of help in giving realistic expectations of adult height.SCOPUS: ar.jinfo:eu-repo/semantics/publishe