نتایج جستجو برای: porous structure

تعداد نتایج: 1609162  

This paper investigates hollow and porous alumina nanospheres that were previously synthesized to be used for the dehydration of methanol to dimethyl ether (DME). As hollow nanostructures possess characteristics such as low density and high surface to volume ratio, their catalytic activity between hollow and porous structure is compared. For this purpose, three most important parameters (acidit...

2012
Mark-Daniel Gerngross Jürgen Carstensen Helmut Föll

: A process chain for a magnetoelectric device based on porous InP will be presented using only chemical, electrochemical, photoelectrochemical, photochemical treatments and the galvanic deposition of metals in high-aspect-ratio structures. All relevant process steps starting with the formation of a self-ordered array of current-line oriented pores followed by the membrane fabrication and a pos...

Journal: :Physical review letters 2009
Tyler R Brosten Sarah L Codd Robert S Maier Joseph D Seymour

Nuclear magnetic resonance measurements of scale dependent dynamics in a random solid open-cell foam reveal a characteristic length scale for transport processes in this novel type of porous medium. These measurements and lattice Boltzmann simulations for a model foam structure indicate dynamical behavior analogous to lower porosity consolidated granular porous media, despite extremely high por...

Journal: :journal of particle science and technology 0
nader rostamizadeh department of chemistry, science and research branch, islamic azad university, tehran,iran mirabdullah seyedsadjadi department of chemistry, science and research branch, islamic azad university, tehran,iran s. a. sadjadi institute of water and energy, sharif university of technology, p.o. box 11365-8639, tehran, i. r. iran

this paper investigates hollow and porous alumina nanospheres that were previously synthesized to be used for the dehydration of methanol to dimethyl ether (dme). as hollow nanostructures possess characteristics such as low density and high surface to volume ratio, their catalytic activity between hollow and porous structure is compared. for this purpose, three most important parameters (acidit...

Journal: :Microelectronics Journal 2005
N. L. Ivina L. K. Orlov V. B. Shevtsov N. A. Alyabina

Recently, porous materials on the base of semiconductor crystals arouse greater interest as photon crystals in terms of opto-electronic applications and formation of arrays of nano-elements with oneand zero-dimensionality. The crystals of porous silicon have been developed best to date. The obvious trends in this field now are towards using other materials for electrolytic etching, decreasing t...

2010
Katalin Sinkó

Silica or various silicate aerogels can be characterized by highly porous, open cell, low density structures. The synthesis parameters influence the three-dimensional porous structures by modifying the kinetics and mechanism of hydrolysis and condensation processes. Numerous investigations have shown that the structure of porous materials can be tailored by variations in synthesis conditions (e...

2010
Juchen Guo Xilin Chen Chunsheng Wang

A unique methodology of fabricating Si anodes for lithium-ion batteries with porous carbon scaffold structure is reported. Such carbon scaffold Si anodes are fabricated via carbonization of porous Si-PVdF precursors which are directly deposited on the current collector. Unlike the conventional slurry casting method, binder and conductive additives are not used in the preparation of the carbon s...

A. Ghasemi, A.R. Yadegari Naeini Yadegari Naeini

Porous materials are lightweight, flexible and resistant to hairline cracks, so today with the development of technology porous structure produced for use in various industries. This structure widely use in beams, plates and shells. The purpose of this paper is to investigate the effect of porosity in axial symmetry in bending and buckling load sheet for analysis. For this purpose, a circular p...

2012
Xuhui Feng Xiaopeng Huang Xinwei Wang

Introduction Single anatase TiO2 nanowire is synthesized using electrospinning technique and is then bridged over a preprocessed 100 m-wide TEM grid for thermal characterization. Transient electrothermal method is applied with proper calibration process for determining major thermophysical properties. SEM diagnostics of the sample show that calcinations for crystal structure transition from am...

2003
C. K. Inoki

The morphology of the porous network in porous SiC has been studied. It has been found that pore formation starts with a few pores on the surface and then the porous network grows in a V-shaped branched structure below the surface. The hydrogen etching rates of porous and nonporous SiC have been measured. Etch rates of porous and nonporous wafers of various miscuts are found to be equal within ...

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