Materials Literature
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This article reviews the recent progress made in asymmetric catalysis in the nanopores of mesoporous materials and periodic mesoporous organosilicas (PMOs). Some examples of chiral catalysts within the nanopores show improved catalytic performance compared to homogeneous catalysts. The factors including the confinemen…
This paper addresses the geometric random packing and void fraction of polydisperse particles. It is demonstrated that the bimodal packing can be transformed into a continuous particle-size distribution of the power law type. It follows that a maximum packing fraction of particles is obtained when the exponent (distri…
We investigated the effect of substrate-induced strain on the metal-insulator transition (MIT) in single-crystalline VO(2) nanobeams. A simple nanobeam-substrate adhesion leads to uniaxial strain along the nanobeam length because of the nanobeam's unique morphology. The strain changes the relative stability of the met…
A new europium(III) complex, [4'-(10-methyl-9-anthryl)-2,2':6',2"-terpyridine-6,6"-diyl]bis(methylenenitrilo) tetrakis(acetate)-Eu(3+), was designed and synthesized as a highly sensitive and selective time-gated luminescence probe for singlet oxygen ((1)O2). The new probe is highly water soluble with a large stability…
Bisthienylethenes (BTEs) are one of the most promising families of photochromic compounds because of their fatigue resistance and thermally irreversible properties for use in optoelectronic devices such as ultrahigh-density optical data storage, molecular switches, logic gates, molecular wires, sensors, and so on. Thi…
Temperature variations of the electron magnetic resonance (EMR) spectra and magnetization measurements are used to show that Ce 3+ ions in concentration ≃18% are present in 3 nm CeO 2 nanoparticles supported on silica aerogel. It is argued that the presence of Ce 3+ implies the defect structure CeO 2- x for ceria nano…
Recent nanomechanical tests on submicron metal columns and wires have revealed a dramatic increase in yield strength with decreasing sample size. Here, we demonstrate that nanoporous metal foams can be envisioned as a three-dimensional network of ultrahigh-strength nanowires, thus bringing together two seemingly confl…
The development of a reversible chemical sensor based on a CdSe/ZnS nanocrystal (NC) is described. Signal transduction is accomplished by fluorescence resonance energy transfer (FRET) between the NC and a fluorescent pH-sensitive squaraine dye attached to the surface of the NC. The efficiency of FRET, and consequently…
Abstract One of the key challenges in nanotechnology is to control a self‐assembling system to create a specific structure. Self‐organizing block copolymers offer a rich variety of periodic nanoscale patterns, and researchers have succeeded in finding conditions that lead to very long range order of the domains. Howev…
The authors have experimentally investigated photoexcitation effects on carrier transports through a Ge quantum-dot (QD)∕SiO2 system via a resonant tunneling diode (RTD). Features of resonant oscillation and negative differential conductance are observed from the tunneling current of Ge-QDs RTDs at room temperature. T…
The authors investigate the effect of the surface treatment on the electrical response of a nematic liquid crystal cell. The theoretical analysis is performed by describing, from the electrical point of view, the liquid crystal and the surface treatment by means of the dielectric constants and the electrical conductiv…
Self-organized construction of advanced materials and devices has been carried out starting with tailor-made colloidal nanoparticles as building blocks. Multilayer thin films of gold nanoparticles stabilized by glutamates and zinc sulfide nanoparticles capped with chitosan were self-organized by a modified polyelectro…
Der aktiven Spezies auf der Spur: Rechnungen erklären die Bildung und Aktivität einzelner Goldatome in der heterogenkatalysierten Hydrierung von 1,3-Butadien. Die aktive Spezies ist ein AuI-Komplex, der in situ durch Reduktion von AuIII entsteht und durch ZrO2-Defekte stabilisiert wird. Die hohe katalytische Aktivität…
The X-ray diffraction in the Laue geometry is investigated in germanium and silicon single crystals upon excitation of long-wavelength ultrasonic elastic strain waves traveling along the sample surface. The X-ray diffraction beam is bounded by a slit 0.2 mm in size, which is considerably less than the wavelength of th…
Abstract Different blends of high‐density polyethylene (HDPE) with calcium carbonate (CaCO 3 ) were mechanically tested under uniaxial tension with or without poly(ethylene‐ co ‐octene) elastomer grafted with maleic anhydride (POE g ), as an impact modifier. In some materials, the surface of the CaCO 3 was treated wit…
Anisotropic helical structures in Fabry-Perot (FP) cavities are shown to exhibit unique properties. The FP peaks are unpolarized, consisting of doublets corresponding to Bloch-Lyaponov eigenwaves with increased splitting as the local anisotropy increases and as they become closer to the photonic bandgap. The Bragg-typ…
The authors report on nondegenerate four-wave mixing in the near infrared using a one-dimensional chalcogenide-glass based photonic crystal. For 76 lattice constants, they find a 3.5-fold enhancement of the mixing signal with respect to the optimum-thickness bulk chalcogenide film. The key is the ability to tailor the…
The dynamical Born charge tensor of brookite $\mathrm{Ti}{\mathrm{O}}_{2}$ has been calculated and analyzed in terms of the Wannier functions associated with the O $2s∕2p$ valence states. It is shown that the fundamental $\mathrm{O}{\mathrm{Ti}}_{3}$ triangular complex, whose opposite distortion in rutile and anatase…
The texture of feeble magnetic ceramics can be controlled by a strong magnetic field. When the magnetic susceptibility of the c axis is smaller than that of the other axes, the c axis aligns perpendicular to the magnetic field; however, the direction is randomly oriented on the plane perpendicular to the magnetic fiel…
Diffraction anomalous fine structure (DAFS) spectroscopy has been applied to resolve site-specific Mn local structure in manganese ferrite films grown under nonequilibrium conditions. The DAFS spectra were measured at a number of Bragg reflections in the vicinity of the Mn absorption $K$ edge. The DAFS data analysis d…