Materials Literature
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The flocculation of colloidal nanosheets of MnO2 with Al13 Keggin ions produces a novel pillared structure with a double-layer arrangement of Al13 species, which exhibits a large intersheet spacing of 2.3 nm and a well-defined mesoporosity. The Figure shows a schematic representation of the formation process.
The coalescence stability of poly(dimethylsiloxane) emulsion droplets in the presence of silica nanoparticles ( approximately 50 nm) of varying contact angles has been investigated. Nanoparticle adsorption isotherms were determined by depletion from solution. The coalescence kinetics (determined under coagulation cond…
Flavodoxins are classified in two groups according to the presence or absence of a approximately 20-residue loop of unknown function. In the accompanying paper (36), we have shown that the differentiating loop from the long-chain Anabaena PCC 7119 flavodoxin is a peripheral structural element that can be removed witho…
The 2 K field-dependent magnetization, M ( H ), of S = 3 / 2 [Ru II/III 2 (OAc) 4 ] + was studied. [Ru II/III 2 (OAc) 4 ] + exhibits an unusually low magnetization with respect to that predicted by the classical Brillouin function. This reduced value is a consequence of the large anisotropy arising from the large zero…
Ultrahigh pore density nanoporous films with cylindrical pores that are perpendicular to the substrate and parallel to each other have been fabricated, and the Al nanocylinders successfully removed (see Figure). The template-assisted growth of ultrahigh density Ni nanowire arrays have also been achieved by direct-curr…
The interactions between [Ru(bpy) 3 ] 2+ and the polyoxotungstate anion [S 2 W 18 O 62 ] 4- in acetonitrile solution were investigated using a combination of photophysics and optical and Raman spectroscopies. The presence of ion clusters of {[Ru(bpy) 3 ][S 2 W 18 O 62 ]} 2- ( K 2 = 7.7 × 10 5 ) and [Ru(bpy) 3 ] 2 [S 2…
Mesostructured silica tubes and rods were prepared by deposition of a prehydrolysed silica sol with surfactant onto the cylindrical pores of a polycarbonate (PC) membrane template, followed by calcination to remove the surfactant and membrane template. The tubular and rodlike morphologies of mesostructured silica were…
Although Lactococcus is one of the most extensively studied lactic acid bacteria and is the paradigm for biochemical studies of citrate metabolism, little information is available on the regulation of the citrate lyase complex. In order to fill this gap, we characterized the genes encoding the subunits of the citrate…
One-dimensional holographic photonic crystals that incorporate photochromic azobenzene-derived liquid crystals (LCs) have been produced. The additive photochromic molecules disrupt the host LC nematic order, inducing an isothermal phase transition and changing the effective dielectric properties of the LC layer (see F…
Pt nanoparticles are incorporated in the three-dimensional nanospace inside single-walled carbon nanohorns using a simple colloidal preparation method. The Pt particles are preferentially deposited inside nanohorns and are located near the defects (see Figure).
Abstract Layer‐by‐layer (LbL) assembly of polymer electrolyte multilayers is now a well‐established method for the fabrication of thin films by sequential adsorption of alternating layers of oppositely charged polyelectrolytes. Most commonly, such adsorptions have been from quiescent solutions of varying ionic strengt…
We have measured the electrical resistance R between the ends of a multiwall carbon nanotube during telescopic extension of the nanotube. R increases monotonically with extension and is hysteresis free, demonstrating that a telescoping nanotube constitutes a near-ideal nanometer-scale rheostat. The functional form of…
The refractive index dependence of the spontaneous emission rate is determined using organically capped CdSe and CdTe quantum dots as probes. The radiative lifetime of the exciton emission is measured in a variety of apolar solvents with refractive indices n between 1.37 and 1.50. It is demonstrated that quantum dots…
Poly(ethylene glycol)-poly(epsilon-caprolactone) diblock copolymers PEG-PCL were synthesized by ring-opening polymerization of epsilon-caprolactone using monomethoxy poly(ethylene glycol) as the macroinitiator and calcium ammoniate as the catalyst. Obvious mutual influence between PEG and PCL crystallization was studi…
The two-dimensional $^{17}\mathrm{O}$ dynamic-angle spinning solid-state nuclear magnetic resonance spectrum of silica glass produced from the melt was measured. From this spectrum a three-dimensional histogram correlating $^{17}\mathrm{O}$ chemical shift, quadrupolar coupling constant, and quadrupolar coupling asymme…
Cubic ZnSe nanowires with periodically alternating twins along the wire growth direction (see Figure) have been synthesized using thermal evaporation with a Au catalyst. The periodicity of the alternating twins has a linear dependence on the diameter of the nanowires. Sharp excitonic peaks dominating the low-temperatu…
Magnetization plateaus, visible as anomalies in magnetic susceptibility at low temperatures, are one of the hallmarks of frustrated magnetism. We show how an extremely robust half-magnetization plateau can arise from coupling between spin and lattice degrees of freedom in a pyrochlore antiferromagnet, and develop a de…
CO adsorption on Cu(111) and Cu(001) surfaces has been studied within ab-initio density functional theory (DFT). The structural, vibrational and thermodynamic properties of the adsorbate-substrate complex have been calculated. Calculations within the generalized gradient approximation (GGA) predict adsorption in the t…
In the context of spin electronics, the two spin-channel model assumes that the spin carriers are composed of two distinct populations: the conduction electrons of spin up, and the conduction electrons of spin down. In order to distinguish the paramagnetic and ferromagnetic contributions in spin injection, we describe…
The frequency dependence of the self energy of a general many--body problem is identified as a main obstacle in correlation calculations based on local approaches. A frequency independent formulation is proposed instead and proven to yield exactly the same numerical results as the original common scheme. Our approach…