Anodic porous

Masuda, H., Ohya, M., Asoh,H., and Nakao, M., Photonic crystal using anodic porous alumina. Jpn. J. Appl. Phys. 38,1403 (1999). 

A1203. Alumina nanotubes have been prepared by electrochemical means.12 Two different preparation methods designated as normal stepwise anodization (NSA) and lateral stepwise anodization (LSA) have been employed for the purpose. The major difference between the two methods is the way the potential was applied. An aluminium film deposited on a p-type Si substrate was anodized in dilute H2SO<. In NSA, the potential was applied to the bottom surface of the Si substrate, while in LSA, it was applied to the top surface of the alumina film. The nanotubes formed were attached to the anodic porous alumina film (Fig. 34a). The NSA tubes were smaller than the LSA tubes. In addition to straight alumina nanotubes, branched alumina nanotubes were also obtained in the same synthesis (Fig. 34b).12,98... 

Y. Kato, T. Ito, and A. Hiraki, Initial oxidation process of anodized porous silicon with hydrogen atoms chemisorbed on the inner surface, Jpn. J. Appl. Phys. 27, L1406, 1988. 

N. Noguchi, I. Suemune, M. Yamanishi, G. C. Hua, and N. Otsuka, Study of luminescent region in anodized porous silicons by photoluminescence imaging and their microstructures, Jpn. J. Appl. Phys. 31, L490, 1992. 

H. Sugiyama and O. Nittono, Microstructure and lattice distortion of anodized porous silicon layers, J. Cryst. Growth 103, 156, 1990. 

K. H. Jung, S. Shih, T. Y. Ksieh, D. L. Kwong, andX. L. Lin, Intense photoluminescence from laterally anodized porous Si, Appl. Phys. Lett. 59(25), 3264, 1991. 

Carbonyl difluoride is formed electrochemically by introducing CO into the pores of a porous anode (porous carbon) of an electrolysis cell containing anhydrous hydrogen fluoride with a small quantity of a metal fluoride, such as KF, to provide adequate conductivity [368], Whilst the stoicheiometry corresponds to ... 

Asoh, H., Nishio, K., Nakao, M., Tamamura, T., and Masuda, H. 2001. Conditions for fabrication of ideally ordered anodic porous alumina using pretextured Al. Journal of the Electrochemical Society 148, B152-B156. 

Masuda H, Hasegwa F, Ono S (1997) Self-ordering of cell arrangement of anodic porous alumina formed in sulfuric acid solution. J Electrochem Soc 144 L127-L130... 

Masuda H, Satoh M (1996) Fabrication of gold nanodot array using anodic porous alumina as an evaporation mask. Jpn J Appl Phys 35 L126-L129... 

Ohmori, T., T. Kimura, and H. Masuda, Impedance measurements of a platinum cylindrical porous electrode replicated from anodic porous alumina. Journal of the Electrochemical Society, 1997. 144 p. 1286... 

In almost all applications up to now the research of porous silicon was mainly concentrated on the growth and investigation of thick layers. Little has been reported for the structure of very thin anodic layers formed at early stages of anodization [11]. The need for thin anodic porous silicon layers locally grown... 

Anodic porous alumina is conventionally grown on aluminum foils, as indicated in Fig. 2. Similar self-assembled growth is achieved on Si by depositing an A1 thin film on the front side of a silicon wafer and forming an ohmic contact on the back side that is used as anode. The electrochemical solutions currently used are oxalic or sulfuric acid aqueous solutions. Details for the fabrication of thin alumina templates on Si with adjustable pore size and density are given elsewhere [8]. Electrochemical oxidation of A1 starts from the A1 surface and continues down to the Al/Si interface, following an anodization current density/time curve as shown in Fig. 3. 

Figure 2. Anodic porous alumina films on Al. Self-assembled vertical cylindrical pores distributed in a hexagonal close-packed structure are formed during anodization.

Figure 3. (a) Anodization curve (current density versus time) for anodic-porous-alumina-on-Si template formation, (b) A1 film on Si before anodization (cross section left and plan view right) and (c) resulting alumina film on Si (cross section (left) and plan view (right)) after anodization. Anodization in (c) stopped at the point indicated by an arrow in the anodization curve (a). 

Figure 7. Example of AFM images of SiO2 dots grown electrochemically through anodic porous alumina on Si after dissolution of the A12O3 template, (a) 2-D AFM image (scanned area 500 nm x 500 nm), (b) 3-D AFM image (scanned area 0.15 pmx 0.15 pm in (b)). The alumina template was 750 nm thick and it was grown in sulfuric add aqueous solution with the concentration of 6 % in volume under constant voltage bias of 20 V.

ANODIC POROUS AND PILLAR STRUCTURES FOR VERTICAL ALIGNMENT OF NEMATIC LIQUID CRYSTALS... 

Fig. la,b demonstrates the top view of the as-anodized porous alumina and the LC alignment on this surface. The LC alignment on the porous alumina film was the same as on the planar non anodized area of the aluminum film (the top left part in Fig. lb). It means that the LC could not penetrate in the pore space through the narrow pore entrance. The porosity of as-anodized films was about 15 %, and pore had the bottleneck form with the entrance diameter of about 5-10nm[6]. Such narrow pore entrance was not enough for the LC penetration into the closed porous space resulting in its horizontal alignment on the porous surface as on the planar non anodized aluminum surface. 

Figure 1. Porous alumina surface and a LC alignment into the porous alumina with different postanodizing treatments a) the as-anodized (Uf=20 V) porous alumina surface b) the LC on the as-anodized porous alumina c) the porous alumina surface after the pore enlargement for 30 min d) the LC on the porous alumina after pore etching.

Hidetaka Asoh, Sachiko Ono, Tomohito Hirose, Masashi Nakao, Hideki Masuda, Growth of anodic porous alumina with square cells, Electrochim. Acta 48 (2003) 3171-3174. 

Fig. 8.14 Left) Computational domain in the model by Yang et al. right) calculated distribution of methanol concentration in the anode porous region and membrane (unit m /s) (Source [180] reproduced with permission of Elsevier)...

Sano T et al (2003) Size-exclusion chromatography using self-organized nanopores In anodic porous alumina. Appl Phys Lett 83(21) 4438-4440... 

A bench-scale steam electrolyser was fabricated and pure hydrogen gas extracted at the rate of a few litres per hour . Fig. 34.6 represents the cross section of the cell which contains a one-end-closed ceramic tube made of SeCeo.95Ybo.05O3-a (inside diameter 12-14 mm, thickness 1-1.5 mm, length 35-150 mm). As a cathode, porous platinum was baked on the inner side of the tube, and, as an anode, porous palladium was attached to the outer side of the tube. Four cells could be accommodated in a cell furnace and connected electrically either in series or in parallel. Steam... 

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