Home About us Contact
|
Home About us Contact | ||
|
|
||
Selective Deposition (selective + deposition)
Selected AbstractsSurface Selective Deposition of PMMA on Layered Double Hydroxide Nanocrystals Immobilized on Solid Substrates,ADVANCED MATERIALS, Issue 5 2009Jong Hyeon Lee A novel nanostructured hybrid PMMA/MgAl-LDH thin film enables a strong UV-blocking effect, up to 97% below 300,nm, and excellent visible transparency. The graft density of PMMA films can be controlled by adjusting the area coverage of immobilized LDH monolayer with a highly-orientated structure on oxide, metal, and polymer substrates. [source] Asymmetric Dumbbells from Selective Deposition of Metals on Seeded Semiconductor Nanorods,ANGEWANDTE CHEMIE, Issue 16 2010Sabyasachi Chakrabortty Das Wachstum von Au- und Ag2S-Nanopartikeln an bestimmten Stellen von CdS-Nanostäben mit CdSe-Keimen lässt sich über die Konzentration der Au- bzw. Ag-Vorstufe steuern. Auf diese Weise sind ,Janus"-Nanostabstrukturen zugänglich, in denen Au am reaktiveren Ende und Ag2S am anderen Ende zu finden ist (siehe Bild; CdSe,dunkelblau, CdS,hellblau, Au,gelb, Ag2S,grau). [source] Selective Deposition of Ultrathin Poly(p -xylene) Films on Dielectrics Versus Copper SurfacesCHEMICAL VAPOR DEPOSITION, Issue 5 2004J.J. Senkevich Ultrathin films of poly(p -xylylene) are selectively deposited on oxide surfaces but not on air exposed copper. The polymers are deposited under conditions favorable for forming highly conformal ultrathin films appropriate for ,pore sealing' the surface of ultra-low , dielectrics. Variable angle spectroscopic ellipsometry is used to measure the polymer deposit on SiO2, and shows the lack of deposition on air-exposed copper. X-ray photoelectron spectroscopic analysis of the copper samples shows deposition of adventitious carbon on the metal surface, and confirms that no polymer deposition occurs. [source] Hydrodenitrification with PdCu Catalysts: Catalyst Optimization by Experimental and Quantum Chemical ApproachesISRAEL JOURNAL OF CHEMISTRY, Issue 1 2006Irena Efremenko A continuous process for nitrate and nitrite abatement from drinking water by catalytic hydrogenation has been developed in our lab. We describe the experimental process development procedure, and support it with semiempirical quantum chemical methods. Comparisons of activated carbon (ACC) and silica glass fiber (GFC) cloths as supports for mono- and bimetallic Pd-Cu catalysts show the former to be 45-fold and 15-fold more active for nitrite and nitrate hydrogenation, respectively, than the latter. Catalysts prepared by selective deposition of Cu on Pd/ACC led to better activity for nitrate hydrogenation than catalysts prepared by co-impregnation or ion exchange methods. The optimal Cu:Pd atomic ratio was found to be 1:2. The computational results show the following: (i) The dispersion of Pd catalysts supported on ACC is much higher than that on GFC due to the larger surface area and higher density of adsorption sites, and that accounts for the higher activity of PdCu/ACC; (ii) Nanosized Pd particles supported on ACC have a semispherical shape and possess preferentially close-packed triangular surfaces, while Pd/GFC particles are extended in the direction parallel to the support surface and show both fcc (100) and (111) planes; (iii) The interaction of Cu atoms with both supports is stronger than that of Pd; adsorbed Cu atoms show a greater ability to form monometallic than bimetallic bonds and that should result in poor mixing of the metal upon co-impregnation, as was observed experimentally; (iv) Cu atoms in bimetallic PdCu particles admit a significant positive charge; the experimentally measured solubility of metal atoms correlates with their calculated charges. The best catalyst (2 wt%Pd-0.6 wt%Cu/ACC) was employed in a novel continuous flow reactor for nitrate hydrogenation in distilled and tap water. The advantages of the reactor investigated over a conventional packed bed reactor are discussed, suggesting a potential for further process intensification. [source] Ink-Jet Printing of Binders for Ceramic ComponentsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2002Jooho Moon Layered manufacturing methods for fabricating ceramic components can involve selective deposition of binder using ink-jet printing. Selection of a proper binder plays a critical role in fabricating parts with good surface finish, dimensional accuracy, and high resolution. Several polymeric solution-phase binders were investigated in terms of their physical properties, printing performance, and binder-powder bed interaction. It was observed that the molecular weight should be <15 000 for the binder to be penetrated into dense powder compacts. Binder infiltration kinetics and printed line width were also significantly influenced by powder-bed characteristics, such as surface roughness and pore size, as well as the physical properties of the binder, such as viscosity and surface tension. [source] Influence of different sources and levels of dietary protein and lipid on the growth, feed efficiency, muscle composition and fatty acid profile of Snakehead Channa striatus (Bloch, 1793) fingerlingAQUACULTURE RESEARCH, Issue 9 2010Mohammed Aliyu-Paiko Abstract Nine isoenergetic (18.5 kJ g,1) diets were formulated, in a 3 × 3 factorial design, by varying three levels of dietary protein (350, 400 and 450 g kg,1) at each of three levels of dietary lipid (65, 90 and 115 g kg,1) accordingly. Each diet was hand fed two times daily for 8 weeks to triplicate homogenous groups of eight fish (average weight 3.34 ± 0.02 g) per tank connected to a recirculation system. Results showed that the feed efficiency and growth performance significantly (P<0.05) increased with increasing protein level at the two lower lipid levels (65 and 90 g kg,1), respectively, as indicated by indices such as %weight gain, specific growth rate, protein efficiency ratio, feed conversion ratio and feed intake, but did not at the highest lipid level (115 g kg,1). The muscle polyunsaturated fatty acids (PUFA) content declined with increasing dietary protein level at the lipid levels producing the highest growth, suggesting that the utilization of PUFA influences growth. Whereas the muscle monounsaturated fatty acids level was generally lower than the dietary levels in all the treatments tested, indicating preferential catabolism for energy, the muscle saturated fatty acids level was comparatively higher than in the diets, indicating selective deposition. Docosa hexaenoic acid (22:6n3, DHA), which was very low in the diet and in the initial fish, was higher in the muscle of some of the treatments, indicating the ability of Channa striatus to desaturate and elongate short-chain PUFA to long-chain HUFA, due to the availability of dietary 18:3n3 and 20:5n3 (the precursors for DHA biosynthesis). It could be concluded, based on the results of this trial, that a diet formulated to contain 65 g kg,1 lipid and 450 g kg,1 protein, with a gross energy of 18.5 kJ g,1 and a dietary n3/n6 PUFA ratio of about 0.1, is sufficient to promote good feed efficiency and growth performance in C. striatus fingerling. [source] | |||||||||||||