Materials Literature
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Ein Netz aus Platinnanoröhren mit Durchmessern von etwa 15 nm und Wanddicken von 1 nm, die sich zu einer offenen, doppelt bikontinuierlichen Struktur verbinden (siehe hochaufgelösten Elektronenmikrograph), entsteht, wenn Platin auf ein nanoporöses Goldtemplat aufgebracht und dieses anschließend aufgelöst wird. Die Str…
Semicrystalline polymer/layered silicate nanocomposites were prepared by solution blending of a low molecular weight poly(ethylene oxide) (PEO) with an organically modified montmorillonite, Cloisite 10A (C10A). The intercalation morphology was studied by temperature-dependent synchrotron wide-angle X-ray diffraction (…
The adsorption of Fe adatoms on MgO(001) surfaces was studied using the ab initio method based on the density-functional theory. On the MgO(001) surfaces, an ${F}_{s}$ oxygen-vacancy site is considered a preferential adsorption site for the formation of metal islands. For the Fe adsorption, calculations in this study…
The phase-correcting Fresnel zone plate provides lens-like focusing and imaging of electromagnetic waves by means of diffraction instead of refraction, often referred to as diffraction optics. The zone plate has seen extensive investigation and use at microwave and millimeter-wave frequencies, and recently has been ap…
We present scanning photoluminescence (PL) microscopy of freely suspended single-walled carbon nanotubes grown by chemically assisted vapor deposition (CVD) across micron-sized open apertures. Scans of the PL emission versus excitation position show unusual "holes"having subwavelength spatial features associated with…
New materials with improved mechanical properties and high optical transmission in the full 3-5 micron MWIR region wavelength are required. Commercially available polycrystalline transparent Yttria, with >100 micron average grain size, does not perform satisfactorily in demanding applications because of its modest str…
Using 2 H NMR and high-precision dielectric spectroscopy, we identified in polybutadiene (PB) at low temperatures (20−100 K) a third relaxation process (γ-process) in addition to the α- and β-processes. PB samples with different molecular weights ( M w ) exhibit a strongly varying relaxation strength (Δε γ ) though no…
In this work, we use AFM measurements in conjunction with dialysis experiments to study the synthesis mechanism and physical state of dendrimer-stabilized platinum nanoparticles. For characterizing particle size distributions by high resolution transmission electron microscopy and AFM, sample preparation by drop evapo…
New military requirements have reinvigorated the need for transparent magnesium aluminate (MgAl<sub>2</sub>O<sub>4</sub>) spinel. Surmet has developed a process that yields high quality transparent spinel at production scale. Several issues related to the extreme requirements of processing ultrafine spinel powders are…
Colloidal chemistry routes are exploited to assemble low-dimensional structures. The creation of hybrid assemblies of aligned carbon nanotubes (CNTs) on silica microparticle assemblies (see images) opens up possibilities for controlling CNT growth using colloidal chemistry, and sheds light on factors that may hinder a…
We employ self-consistent field theory to calculate binodals and spinodals of an asymmetric binary polymer blend in a thin film. The film surface and substrate of the film attract both the same component via short-range interactions. The ratios of chain lengths, segment lengths, and segment volumes are chosen to match…
A recently developed constitutive model and a finite element formulation for predicting the thermomechanical response of shape memory alloy hybrid composite (SMAHC) structures are briefly described. Attention is focused on constrained recovery behavior in this study, but the constitutive formulation is also applicable…
The U.S. Naval Research Laboratory (NRL) has developed two unique materials with excellent properties for various military and commercial applications in the UV-Vis-IR wavelength range. These materials are: an amorphous Barium Gallo-Germanate (BGG) glass and a polycrystalline Magnesium Aluminate Spinel. The BGG glass…
Structural behavior and phase transitions in the A-cation deficient perovskite-like solid solutions (1 − x )LaMg 0.5 Ti 0.5 O 3 - x La 2/3 TiO 3 (0 ≤ x ≤ 0.5) were studied to reveal crystal-chemical factors associated with the marked variation of dielectric properties with x -value. Structures and phase transisitons w…
Different non-ionic cellulose ethers like methyl cellulose (MC), hydroxypropyl cellulose (HPC) and hydroxypropylmethyl cellulose (HPMC) were investigated. The characterization of the cellulose ethers was carried out by thermogravimetry and sorption/desorption isotherms. Differences in the properties of the cellulose e…
Both Ni- and Co-MCM-41 may be used for the synthesis of single-wall carbon nanotubes (SWNT). We present a comparative investigation that demonstrates that smaller diameter SWNT with a narrower distribution of diameters are produced using Co-MCM-41. Temperature-programmed reduction and x-ray absorption spectroscopy wer…
ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication to the EditorNEXTDirect Synthesis of Poly(lithium organoborate)s and Their Ion Conductive PropertiesNoriyoshi Matsumi, Kazunori Sugai, Kenji Sakamoto, Tomonobu Mizumo, and Hiroyuki OhnoView Author Information Department of Biotechnology, Tokyo Universit…
Abstract Summary: We used a custom designed dilatometer to measure quantitatively the time evolution of the specific volume of (semi‐crystalline) polymers for an unusual combined wide range of cooling rates and elevated pressures, covering processing conditions. For an isotactic poly(propylene), applying the Schneider…
Basic considerations for implementing combinatorial approach to molecular beam epitaxy (MBE) are discussed, focusing on the key issues relevant to conventional MBE synthesis using solid sources and characterization. The primary objective for implementing combinatorial approach is to make MBE do more, more able to carr…
Dialkyltin dichloride grafted to a cross-linked polystyrene, with the formula [P-H]((1-t))[P-(CH2)nSnBuCl2]t (P=[CH2CH(pC6H4)], t=the degree of functionalization, and n=6 or 11), is investigated as a recyclable catalyst in the ring-opening polymerization (ROP) of epsilon-caprolactone (CL). It is demonstrated that high…