Porous transmission electron microscop

Transmission electronic microscope picture of a porous nanocrystalline 2... 

Fig. 20. Transmission electron microscope image of the cross-section of a porous layer formed in n-Si(lOO), 0.1 2 cm, in HF (49wt.%) - C2H5OH (1 1 by volume) at SOmAcm [83].

Fig. 22. Transmission electron microscope image of the porous layer in Fig. 20 showing an individual pore [83].

Microstructure of porous anodic oxide films was investigated with transmission electron microscope JEM-T6 and scanning electron microscopes JSM-840 and JSM-35. 

Semicokes prepared at various temperatures were examined in the transmission electron microscope, but few features could be seen in the lower- and higher-temperature samples. Because of the porous and brittle nature of semicoke, it was difficult to prepare good ion-thinned sections as we did for coal. Therefore, features such as spheres and rods may have been destroyed during grinding to prepare the sample. 

Martin-Palma RJ, Pascual L, Herrero P, Martinez-Duart JM (2002) Direct determination of grain sizes, lattice parameters, and mismatch of porous silicon. Appl Phys Lett 81 25-27 Martin-Palma RJ, Pascual L, Landa A, Herrero P, Martinez-Duart JM (2004) High resolution transmission electron microscopic analysis of porous silicon/silicon interface. Appl Phys Lett 85(13) 2517-2519... 

A new class of siliceous microporous materials with varying metal contents and high porosities has recently been presented by Maier et al. [105,106]. These materials which are X-ray amorphous and where no crystalline structure can be seen in the transmission electron microscope are synthesized via a sol-gel-route under hydrothermal conditions without the use of template molecules. The simple reaction of silicon alcoholates and titanium alcoholates which are mixed in ethanol and the condensation of which is induced by the addition of hydrochloric acid, produces a gel that becomes solid after a few days. The following careful calcination process under inert atmosphere and milling of the resulting solid gives the porous material. Detailed analysis of the pore structure para-... 

N2 adsorption at 77 K was performed in a Quantachrome Autosorb-6B gas adsorption analyzer to derive information on the porous characteristics of the non-treated and treated samples. Prior to the adsorption measurement the samples were treated in vacuum at 573 K for 12 h. Transmission Electron Microscopy was measured in a Zeiss lOCA microscope. Si, Al, and Fe concentrations in the zeolites and in the filtrates obtained upon alkaline treatment were determined by ICP-OES in a Perkin-Elmer Optima 3000DV. 

This microstructure has been investigated by up-to-date methods especially the scanning electron microscope examination proved the presence of fractures, cavities and matrix porosities wich, in reservoir engineers opinion, deciding determine the transmissibility of methane (the permeability of coal). It is true, that commercial gas production to date has been hampered by the low permeabilities of coal seams. For example the permeability of a good porous sandstone reservoir is between 0.1-0.5 pm just then a coal seam has only 5-20.10-3 permeability but there are coals with permeability between 10- >-10 pm. As it will be discussed in point 4 the low permeability is indeed the greatest problem of methane recovery from coal seams. 

The transmission electron microscopy investigations of the upper layer and of the electro-catalytic electrode were carried out on a JEOL 4000 FX microscope. Foils for the electron microscopy investigations were prepared by mechanical polishing followed by ion milling. The structure of the upper YSZ layer sintered at temperature 1450 C is shown in Fig.l5. This figure shows some typacal microstructures of the upper layer. It is seen that upper layer is porous and that the pores form channels with a size of 200-500 nm, or they have ellipsoidal shape with a size 50-100 nm. 

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