Materials Literature
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We present an investigation of the magnetic entropy /spl Delta/S and resistivity /spl rho/, and the relation between them, for La/sub 0.67/Ca/sub 0.33/MnO/sub 3/ film. We found that the maximum /spl Delta/S is approximately 6 J/kg/spl middot/K, and the maximum magnetoresistance (defined as /spl rho/(0)//spl rho/(H)-1)…
We show in this paper that metamaterials in which some components of the permittivity and permeability tensors can have negative real values (thus associated with left-handed metamaterials) call for a reconsideration of the common concepts of critical angle and Brewster angle. By studying the reflection coefficient fo…
Abstract Activity at the NASA Langley Research Center (LaRC) has focused on developing low density polyimide foam and foam structures which are made using monomeric solutions or salt solutions formed from the reaction of a dianhydride and diamine dissolved in a mixture of foaming agents and alkyl alcohol at room tempe…
Novel composite materials based on mixtures of samarium-doped ceria (SDC)-carbonate were examined for use as electrolyte materials in low-temperature solid oxide fuel cells (LTSOFCs) operating at 400-600°C. The composite electrolytes showed high ion conductivity at evaluated temperatures. Composition and calcination t…
Nanoporous carbons obtained by selective leaching of Ti and Al from , as well as B from , were investigated as electrode materials in electric double-layer capacitors. Cyclic voltammetry tests were conducted in from on carbons synthesized at 600, 800, 1000, and . Results show that the structure and pore sizes can be t…
Shaped silica constructed by silica fiber with axial poly(ethyleneimine)s (PEIs) filaments was available simply from rapid hydrolytic condensation of tetramethoxysilane (TMOS) upon aggregates of PEIs with different architecture.
The electrochemical properties of RuO2/LNO and RuO2/SA electrodes made of RuO2 rods and plates of nanometre size on LiNbO3(100) and sapphire(0001) substrates are investigated. Both rods and plates are grown vertically using chemical vapor deposition. The RuO2/LNO electrode has a higher electrolyte/solid surface area c…
Electrically conducting diamond powder was prepared by coating insulating diamond powder ( 8 - 12 μ m diam, ∼ 2 m 2 ∕ g ) with a thin boron-doped layer using microwave plasma-assisted chemical vapor deposition. Deposition times from 1 to 6 h were evaluated. Scanning electron microscopy (SEM) revealed that the diamond…
Textile Technology: The sun-blocking properties of a textile are enhanced when a dye, pigment, delustrant, or ultraviolet absorber finish is present that absorbs ultraviolet radiation and blocks its transmission through a fabric to the skin. For this reason, dyed fabrics provide better sun protection than bleached fab…
Introduction. 1. 1 Cellulose: The Most Abundant Natural Organic Compound. 1. 2 New Era of Cellulose Derivatives as Artificial Materials in Middle 19th Century: Cellulose Chemical Industries . 1. 3 Emergence of Polymer Science in 1920s . 1. 4 Further Development of Molecular Characterization of Cellulose and Cellulose…
The significance of kinetics on the development of microstructures in connection with sintering of ceramics is well recognized. In practice, however, it still remains a challenge to prepare designed microstructures via engineering the sintering kinetics because of an insufficient understanding of the different operati…
A general, aerosol-based, one-step approach was explored to synthesize microporous and mesoporous spherical carbon particles with highly porous foam-like structures from aqueous sucrose solutions containing colloidal silica particles and/or silicate cluster templates.
Mesoporous silica materials made by the use of self-assembled surfactants as templates have attracted a lot of interest in recent years. The number of publications on the topic has increased by a factor of 100 between 1993 and 2003. The vast majority of the papers deal with syntheses from organosilicates, such as tetr…
Mid-infrared (IR) spectra of a series of calcium silicate hydrates (C-S-H) gels synthesised from C 3 S in the presence of magnesium oxide show many similarities with the mid-IR spectra of pure C-S-H gels. However, the presence of the vibration bands attributed to brucite is observed in all spectra of C-S-H synthesised…
By applying a seed-mediated growth method that had been reported for the chemical synthesis of Ag nanorods and nanowires in aqueous solution, we successfully attached Ag nanosphere and nanorod particles to indium tin oxide (ITO) surfaces. In this method, it is characteristic that the attachment can be performed withou…
InGaAs with embedded ErAs nano-particles is a promising material for thermoelectric applications. The incorporation of erbium arsenide metallic nanoparticles into the semiconductor can provide both charge carriers and create scattering centers for phonons. Electron filtering by heterostructure barriers can also enhanc…
This paper concerns the hydration and swelling behavior of four synthetic sodium saponite samples with general formula Na x (Si 4-x ,Al x )(Mg 3 )O 10 (OH) 2 , where x = 0.4, 0.5, 0.6, and 0.7. The combination of gravimetric water adsorption measurements and X-ray diffraction experiments under controlled water pressur…
Unique nanorods and nanobelts of Prussian blue (PB) analogue SmFe(CN)6.4H2O have been successfully synthesized by using reverse micelles as colloidal soft templates; magnetic studies show that the shape of the low-dimensional nanoscale material is a dominating factor for its coercivity due to the effect of shape aniso…
The objective of the present study is to synthesize high purity vanadium nitride (VN) nanocrystallites using a two-step ammonolysis of vanadium tetrachloride. VN crystallites were obtained at relatively low temperatures which exhibited a specific capacitance as high as by cyclic voltammetry. The electrochemical respon…
The enhanced non-local gradient-dependent theories formulate a constitutive framework on the continuum level that is used to bridge the gap between the micromechanical theories and the classical (local) continuum. They are successful in explaining the size effects encountered at the micron scale and in preserving the…