Materials Literature
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A new ion-pair complex, 1-benzyl-4-aminopyridinium bis(maleonitriledithiolato)nickelate(III) (1), has been synthesized. The variable magnetic susceptibility results of 1 show a discontinuity around 184 K, which is phenomenologically similar to that observed for first-row transition metal complexes undergoing a spin cr…
We investigate the origin of the Breit-Wigner-Fano line in the Raman spectra of individual single-walled carbon nanotubes and their bundles. Using confocal Raman microscopy and atomic-force microscopy we found that the Breit-Wigner-Fano line intensity increases strongly with the bundle thickness. We confirmed this res…
Tetrakis(trimethylsilyl)tetrahedrane 3 has been synthesized upon irradiation of tetrakis(trimethylsilyl)cyclobutadiene 8, which can be prepared either by thermal nitrogen elimination from trimethylsilyl[1,2,3-tris(trimethylsilyl)-2-cycloprop-1-enyl]diazomethane 7 or by mild oxidation of cyclobutadiene dianion 9 with 1…
In order to prepare bulk C 3 N 4 , high-pressure pyrolysis of melamine (C 3 N 6 H 6 ) at different temperatures was carried out. The products were characterized by C, N, H element analysis, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffractometry. The results of the analysis…
To investigate the dielectric response of isolated single-walled carbon nanotubes, (SWCNTs), spatially resolved electron energy-loss spectroscopy measurements have been carried out using a scanning transmission electron microscope in a near-field geometry. Spectra have been compared with those acquired on multiwalled…
The syntheses and electrooptic properties of a new family of nonlinear optical chromophores are reported. These species feature an ethyne-elaborated, highly polarizable porphyrinic component and metal polypyridyl complexes that serve as integral donor and acceptor elements. Examples of this structural motif include ru…
Cellular solids inherit their macroscopic mechanical properties directly from the cellular microstructure. However, the characteristic material length scale is often not small compared to macroscopic dimensions, which limits the applicability of classical continuum-type constitutive models. Cosserat theory, however, o…
We study the linearized Fopl - von Karman theory of a long, thin rectangular elastic membrane that is bent through an angle $2 α$. We prove rigorous bounds for the minimum energy of this configuration in terms of the plate thickness $σ$ and the bending angle. We show that the minimum energy scales as $σ^{5/3} α^{7/3}$…
The microindentation hardness technique has been employed to examine the II → I polymorphic transformation of i -PBu1 taking place upon aging at room temperature. The hardness values of form I are shown to be remarkably higher than those of form II due to the denser packing of chains in the hexagonal crystal modificat…
We theoretically demonstrate that atomically-precise ``nanoscale processing" can be reproducibly performed by adaptive laser pulses. We present the new approach on the controlled welding of crossed carbon nanotubes, giving various metastable junctions of interest. Adaptive laser pulses could be also used in preparatio…
We consider a 1D lattice gas model in which the atoms interact via an infinite number of cluster interactions within contiguous atomic chains plus the next nearest neighbor pairwise interaction. All interactions are of arbitrary strength. An analytical expression for the size distribution of atomic chain lengths is ob…
We present an ab initio theoretical formalism for the static paramagnetic spin susceptibility of metals at finite temperatures. Since relativistic effects, e.g. spin-orbit coupling, are included, we can identify the anisotropy or easy axes of the spin fluctuations. Our calculations find hcp-iron to be unstable to in a…
Recent investigations of grain growth in nanocrystalline materials have revealed a new growth mechanism: grain-rotation-induced grain coalescence. Based on a simple model employing a stochastic theory and using computer simulations, here we investigate the coarsening of a polycrystalline microstructure due solely to t…
The refractive indices of 509 oxides and 55 fluorides were analyzed using two forms of a one-term Sellmeier equation: (1) 1/(n2−1)=−A/λ2+B, where A, the slope of the plot of (n2−1)−1 versus λ−2 in units of 10−16 m2, gives a measure of dispersion and B, the intercept of the plot at λ=∞, gives n∞=(1+1/B)1/2 and (2) n2−1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical Strategies To Design Textured Materials: from Microporous and Mesoporous Oxides to Nanonetworks and Hierarchical StructuresGalo J. de A. A. Soler-Illia, Clément Sanchez, Bénédicte Lebeau, and Joël PatarinView Author Information Laboratoire de Chimie de la Matière Co…
Two visible luminescence bands are observed in Re4+:Cs2ZrBr6 under NIR excitation at temperatures between 10 and 300 K. We perform absorption, luminescence, excitation, and time resolved spectroscopic studies at various temperatures to characterize this upconversion luminescence and its driving mechanism. From the tim…
A structural model of the antiphase boundaries (APBs) induced by phase transition in perovskite and layered perovskite oxides is put forward. Besides the distortion of oxygen octahedra, the existence of two types of ion with different sizes on A sites in perovskite blocks and their ordering in local areas might be the…
In this experiment we have measured the temperature dependence of field emission characteristics for boron-doped diamond and diamond-like films at various temperatures and low fields. The threshold voltage increases and emission current density decreases as the temperature decreases. These field emission characteristi…
Two genes bearing similarity to alternative sigma factors were identified in the Deinococcus radiodurans genome sequence and designated sig1 and sig2. These genes were cloned and inactivated, and both were found to be important for survival during heat and ethanol stress, although the sig1 mutants displayed a more sev…
High-quality interface between an insulator and ZnO as a wide-band-gap semiconductor should realize devices based on field-effect carrier modulation or superlattices having large band offset over 1 eV. We demonstrate that LiGaO2 could be a possible candidate for this purpose. Heteroepitaxy of LiGaO2 is demonstrated on…