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Efficient Growth (efficient + growth)

Distribution by Scientific Domains

Polymers and Materials Science	50%

Selected Abstracts

Catalyst-Free Efficient Growth, Orientation and Biosensing Properties of Multilayer Graphene Nanoflake Films with Sharp Edge Planes,

ADVANCED FUNCTIONAL MATERIALS, Issue 21 2008
Nai Gui Shang
Abstract We report a novel microwave plasma enhanced chemical vapor deposition strategy for the efficient synthesis of multilayer graphene nanoflake films (MGNFs) on Si substrates. The constituent graphene nanoflakes have a highly graphitized knife-edge structure with a 2,3,nm thick sharp edge and show a preferred vertical orientation with respect to the Si substrate as established by near-edge X-ray absorption fine structure spectroscopy. The growth rate is approximately 1.6,µm min,1, which is 10 times faster than the previously reported best value. The MGNFs are shown to demonstrate fast electron-transfer (ET) kinetics for the Fe(CN)63,/4, redox system and excellent electrocatalytic activity for simultaneously determining dopamine (DA), ascorbic acid (AA) and uric acid (UA). Their biosensing DA performance in the presence of common interfering agents AA and UA is superior to other bare solid-state electrodes and is comparable only to that of edge plane pyrolytic graphite. Our work here, establishes that the abundance of graphitic edge planes/defects are essentially responsible for the fast ET kinetics, active electrocatalytic and biosensing properties. This novel edge-plane-based electrochemical platform with the high surface area and electrocatalytic activity offers great promise for creating a revolutionary new class of nanostructured electrodes for biosensing, biofuel cells and energy-conversion applications. [source]

General Rules Governing the Highly Efficient Growth of Carbon Nanotubes

ADVANCED MATERIALS, Issue 47 2009
Don N. Futaba
The key to highly efficient growth of carbon nanotubes includes two essential ingredients in the growth ambient: a carbon source that does not contain oxygen and a minute quantity of a secondary gas, which does contain oxygen, that acts as a growth enhancer. These and other general rules governing the growth of carbon nanotubes and the fundamental reasons from which they arise are presented. [source]

Isothermal close space sublimation of CdTe/ZnTe heterostructures in vacuum conditions

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010
O. de Melo
Abstract Thin films and structures of ZnTe and CdTe have been grown by isothermal close space sublimation using alternated exposure of single crystalline substrates to elemental Zn, Te and Cd sources. The results show that the use of vacuum conditions promotes the transport of vapors towards the surface and then efficient growth at lower temperatures. Films thickness ranged between 200 and 600 nm for 50 cycles samples. ZnTe and CdTe films were obtained even at temperatures as low as 310 °C. This is important because low temperatures worsen the inter- diffusion processes; as a consequence we have obtained relatively abrupt interfaces in the ZnTe/CdTe system. Its compositional, structural and optical properties are presented. These results offer new possibilities of this low cost technique for growing heterostructures. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Protein lipid ratio for the growth and survival of juvenile crayfish Procambarus acanthophorus (Hobbs 1972) reared under controlled conditions

AQUACULTURE RESEARCH, Issue 9 2010
Enrique Cervantes-Santiago
Abstract The influence of dietary protein/lipid levels on growth and survival in juvenile crayfish (Procambarus acanthophorus) was evaluated during a 12-week nutritional trial. Twenty experimental diets were formulated containing different protein (200, 250, 300, 350 and 400 g kg,1) and lipid (60, 80, 100 and 120 g kg,1) levels. A bifactorial model (5 × 4) was used with three replicates and 15 crayfish (0.014±0.006 g) per replicate, in a recirculation system with 60,15 L rectangular tanks and a biological filter, the culture conditions were a photoperiod of 12:12 h L:D and temperature 24.7±1.0 °C. Total survival ranged from 66.6% to 86.6%, with no differences attributed to treatments. Dietary protein levels had a significant effect on growth gain and nutritional efficiency; in contrast, lipid levels had no effect on juvenile performance. The 250/120 (protein/lipid) treatment promoted the most efficient growth (final weight: 3.09 g, weight gain: 21 995%, specific growth rate: 3.35% day,1); the less efficient growth was observed in juveniles fed with 400 g kg,1 protein diets. The quadratic regression model indicated 279 g kg,1 as the optimal protein level for crayfish growth, while levels between 211 and 232 g kg,1 could minimize the feeding costs without affecting growth. [source]

Protein requirements of Nile tilapia (Oreochromis niloticus) fry cultured at different salinities

AQUACULTURE RESEARCH, Issue 8 2010
Edvino Larumbe-Morán
Abstract Effect of isolipidic (62.7 ± 5.0 g kg,1) diets with protein levels of 204.6 (T20), 302.3 (T30), 424.6 (T40) or 511.0 g kg,1 (T50) on growth and survival in Nile tilapia (Oreochromis niloticus Linnaeus 1758) fry cultured for 70 days at one of four salinities (0, 15, 20 and 25 g L,1) was evaluated. A bifactorial (4 × 4) design was used with 16 treatments run in triplicate and 20 fry (0.25 ± 0.04 g) per replicate under semi-controlled conditions. Four independent, recirculating systems (one per salinity level) were used, each one with 12 circular tanks (70 L capacity), filters and constant aeration. The different salinities had no significant effect on growth. Weight gain improved significantly as dietary protein content increased, although organisms fed the T50 diet had a lower growth rate. Survival was highest (98.33%) in the T50/15 (protein/salinity levels) treatment and lowest (71.0%) in the T20/20 treatment, with no pattern caused by the variables. The T40/25, T40/20 and T50/0 treatments produced the most efficient growth and feed utilization values while the T20 treatments at all the salinities resulted with the lowest performance. With the exception of the T50 treatments, a non-significant tendency to increased weight gain was observed as water salinity increased, suggesting that the salinity of the culture environment does not influence dietary protein requirements in Nile tilapia O. niloticus fry. [source]