Preparation of helical nanostructures using chiral cationic surfactants
Left-handed helical short nanotubes and mesoporous nanofibers were prepared by sol-gel transcription using a new chiral cationic surfactant.
Materials Literature
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Ten isomeric five-ring bent-core mesogens: The influence of the direction of the carboxyl connecting groups on the mesophase behaviour
In order to study the role of the direction of the connecting groups in bent-core mesogens we synthesized two series of ten possible achiral isomeric five-ring bent-core compounds in which all aromatic rings are connected by ester groups and each of which possesses the same length of the terminal chains (octyloxy or d…
Preparation and characterization of a collagen/chitosan/heparin matrix for an implantable bioartificial liver
A new type of collagen/chitosan/heparin matrix, fabricated by gelation of collagen/ chitosan with heparin sodium containing ammonia, was produced to construct livers by tissue engineering and regenerative engineering. The obtained collagen/chitosan/heparin matrix was found to be highly porous, swelled rapidly in PBS s…
99% efficiency measured in the -1st order of a resonant grating
A resonant diffraction grating comprising a mirror, a dielectric layer and a high index corrugation at the layer-air interface is shown to exhibit off-Littrow the record diffraction efficiency of 99% in the -1st reflected order at 1064 nm wavelength thanks to the excitation of a leaky mode of the layer. Such high figu…
Fabrication of Highly Ordered InSb Nanowire Arrays by Electrodeposition in Porous Anodic Alumina Membranes
Highly ordered near-stoichiometrical polycrystalline InSb nanowire arrays have been fabricated by direct current (dc) electrodeposition inside the nanochannels of anodic alumina membranes (AAMs) and subsequent annealing. X-ray diffraction patterns and X-ray energy dispersion analysis reveal the change of crystal struc…
Controlling the size and shape of gold nanoparticles in fulvic acid colloidal solutions and their optical characterization using SERS
The size and shape of nanoparticles can be controlled by varying the pH and concentration of the fulvic acid (FA) colloidal solution. FA thin solid films with embedded Au nanoparticles have been fabricated, and their optical field enhancing properties tested in surface-enhanced Raman scattering (SERS). High-resolution…
Electrodeposition of Silicon from Nonaqueous Solvents
A study of the electrodeposition (ED) of silicon from silicon halides in a nonaqueous electrolyte solution is described. In spite of the use of nonoxidizing electrolytes, the electrodeposits usually become oxidized on air exposure. In similarity to other work, it is postulated that this is due to the deposit being for…
Boundary Conditions in the Vicinity of a Dynamic Contact Line: Experimental Investigation of Viscous Drops Sliding Down an Inclined Plane
To probe the microscopic balance of forces close to a moving contact line, the boundary conditions around viscous drops sliding down an inclined plane are investigated. At first, the variation of the contact angle as a function of the scale of analysis is discussed. The dynamic contact angle is measured at a scale of…
New Lithium-Ion Conducting Crystal Obtained by Crystallization of the Li[sub 2]S–P[sub 2]S[sub 5] Glasses
A lithium-ion highly conductive new crystal was first precipitated in the Li 2 S – P 2 S 5 glass-ceramics obtained by crystal- lization of the glasses. The 70 Li 2 S ⋅ 30 P 2 S 5 ( mol % ) glass-ceramic heated at 360 ° C showed the highest conductivity of 3.2 × 10 − 3 S cm − 1 at room temperature and the lowest activa…
Mild solution synthesis of zinc oxide films with superhydrophobicity and superhydrophilicity
Zinc oxide superstructured films with superhydrophobicity or superhydrophilicity were successfully prepared by treatment of 1 mM of a Zn2+–hexamethylenetetramine mixed solution at 95 °C for a desired aging time.
Carbon nanotube-promoted Co–Cu catalyst for highly efficient synthesis of higher alcohols from syngas
The development of a type of carbon-nanotube-promoted Co-Cu catalyst, which displays excellent performance for highly effective and selective formation of the C(2-4)-oxygenates, especially BuOH and DME, from syngas, is reported.
Direct aerobic epoxidation of alkenes catalyzed by metal nanoparticles stabilized by the H5PV2Mo10O40 polyoxometalate
Ag and Ru nanoparticles stabilized by H5PV2Mo10O40, prepared by a sequence of redox reactions and supported on alpha-alumina, were effective catalysts for the direct aerobic epoxidation of alkenes in the liquid phase.
Synthesis of Au nanoparticle doped SiO2–TiO2 films: tuning of Au surface plasmon band position through controlling the refractive index
The position of the surface plasmon resonance (SPR) band of Au nanoparticles was tailored by controlling the refractive indices (n) of the embedding matrices, to develop different coloured coatings on glass substrates. Five sets of Au nanoparticle doped coatings were prepared from sols derived from tetraethyl orthosil…
Nanomaterials based on metal-containing nanoparticles in polyethylene and other carbon-chain polymers
This paper provides a convenient and simple method for fabricating of large amounts (kilogram-scale) of nanomaterials containing nanoparticles in a polymeric matrix. The encapsulation was done by thermal decomposition of metal containing compounds (MRn; M=Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Mn, Mo, Nd, Ni, Pt, Re, Ti, Pb,…
Backscattered speckle size as a function of polarization: influence of particle-size and- concentration
This report about backscattering measure-ments of the speckle produced by strongly-scattering liquid media shows that the size of the backscattered speckle depends on scattering and anisotropy coefficients. These measurements were aimed at assessing the effects of polarization characteristics of the incident laser bea…
Surface properties of PEO–silicone composites: reducing protein adsorption
Silicone-based polymers with reduced protein adsorption were successfully prepared by incorporating mono- or bifunctional poly(ethylene oxide) (PEO) derivatives, respectively, into PDMS during rubber formation using classic room temperature vulcanization chemistry. Characterization of the films by water contact-angle…
Electrochromic Films Composed of MnO[sub 2] Nanosheets with Controlled Optical Density and High Coloration Efficiency
Electrochemical and electrochromic properties of MnO 2 nanosheet electrodes prepared by layer-by-layer assembly on transparent conductive indium-tin oxide substrates were examined.Cyclic voltammograms ͑CVs͒ of multilayer film electrodes of MnO 2 nanosheets in nonaqueous Li + -containing electrolyte showed well-defined…
Relation between magnetic entropy and resistivity in La/sub 0.67/Ca/sub 0.33/MnO/sub 3/
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)…
REFLECTION COEFFICIENTS AND GOOS-HANCHEN SHIFTS IN ANISOTROPIC AND BIANISOTROPIC LEFT-HANDED METAMATERIALS
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…
Effects of cell structure and density on the properties of high performance polyimide foams
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…