Materials Literature
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We present the result of a systematic study of the tribological properties of industrial Polytetrafluorethylene (PTFE)-based coatings carried out with an atomic force microscope. A new characterization protocol allowed the reliable and quantitative assessment of the friction coefficient and adhesion forces at the sub-…
We present a new method for constant-pressure molecular dynamics simulation which is parameter free. This method is especially appropriate for finite systems in which a periodic boundary condition does not apply. Simulations on carbon nanotubes and Ni nanoparticles clearly demonstrate the validity of the method, from…
Several aspects of the theory of epitaxial crystal growth from atomic or molecular beams are developed from the perspective of statistical physics. Lectures are devoted to the rate equation theory of two-dimensional nucleation and its limitations; the growth of multilayer wedding cakes in the presence of strong step e…
Gold nanowires generated by mechanical stretching have been shown to adopt only three kinds of configurations where their atomic arrangements adjust such that either the [100], [111] or [110] zone axes lie parallel to the elongation direction. We have analyzed the relationship between structural rearrangements and ele…
A structural model of hydrogenated amorphous silicon containing an isolated dangling bond is used to investigate the effects of electron interactions on the electronic level splittings, localization of charge and spin, and fluctuations in charge and spin. These properties are calculated with a recently developed densi…
A molecular precursor approach involving simple grafting procedures was used to produce site-isolated titanium-supported epoxidation catalysts of high activity and selectivity. The tris(tert-butoxy)siloxy titanium complexes Ti[OSi(O(t)Bu)(3)](4) (TiSi4), ((i)PrO)Ti[OSi(O(t)Bu)(3)](3) (TiSi3), and ((t)BuO)(3)TiOSi(O(t)…
The deposition of a thin, metal film onto an array of spherical silica colloids, followed by dissolution of the colloidal template, produces metallic half-shells with nanometer-scale dimensions. Half-shells of gold, platinum, and palladium were fabricated, with diameters of the particles ranging from 100 to 500 nm, an…
Abstract A brief historical perspective relating the discovery of dendrimers and other dendritic polymers is presented. Dendritic polymers are recognized as the fourth major class of macromolecular architecture consisting of four sub‐ classes, namely, (1) random hyperbranched, (2) dendrigrafts, (3) dendrons, and (4) d…
New approaches to synthesize photostable thiol-capped CdTe nanocrystals are reported. Post-preparative size-selective precipitation and selective photochemical etching have been developed as methods providing an increase of photoluminescence quantum efficiency of the nanocrystals of up to 40%. Some advantages of thiol…
The Born-Green-Yvon equation with smoothed density approximation is used to calculate the liquid-liquid density profiles of a symmetric Lennard-Jones fluid in a hard sphere disordered matrix. The phase diagrams are evaluated for model systems characterized by different matrix densities and compared with the results of…
Investigation by transmission electron microscopy and high-resolution transmission electron microscopy was carried out on YBa 2 Cu 3 O 7−δ thin films grown on vicinal SrTiO 3 substrates by pulsed laser deposition. The c -axis YBa 2 Cu 3 O 7−δ films grown on 1°–3° miscut substrates displayed a step-flow crossover to th…
졸-겔 형판 합성법을 이용하여 페로브스카이트 구조를 갖는 나노튜브를 합성하고 그 특성을 조사하였다. PbTiO3(PT), PbZrO3(PZ)와 PbZrO3-PbTiO3(PZT)고용체 나노튜부는 반응물, Ti(OPri)4, Zr(OBu)3와 Pb(OAc)2-3H2O 들의 킬레이트 졸-겔 합성법에 의해서 합성하였다. 산화 알루미늄 형판은 200nm의 직경을 갖는 훠트만 아노디스크가 사용되었다. 6.0M-NaOH 용액에서 형판을 제거한 다음, 주사현미경 분석에 의해서 50m 길이와 200nm 외곽 직경의 생성물 나노튜브를 확인할 수 있었다. 투과현미경 분석과 전자회절 분…
In pursuance of a long-range programme on the hydration, mobility and action of proteins, the structural basis of the stabilizing effect of sugars and polyols is being investigated. With two crystallographically independent molecules with slightly different packing environments in the crystal, monoclinic lysozyme cons…
The synthesis of optically transparent magadiite−silica hybrid monoliths was investigated by the incorporation of delaminated magadiite powders into a sol−gel-derived silica matrix obtained by hydrolysis and condensation of tetramethoysilane (or tetramethyl orthosilicate or TMOS). The delamination of sodium magadiite…
Surface-enhanced Raman spectroscopy has been extended successfully to the study of a bare iron electrode (without any deposition of other noble metals) exposed to the neutral solution containing thiocyanate over a wide potential range from −1.8 to −0.4 V. The applied potential has a significant influence on the Raman…
A model has been developed for describing the stresses that arise during binder burnout in three-dimensional porous bodies. The pressure gradient that arises from the decomposition of binder in the pore space is treated as an equivalent body force. For input into the mechanics model, the pressure distribution is obtai…
The interaction between two spheres in a solution of nonadsorbing polymers, with excluded volume interaction, is calculated from the depletion layers around the spheres using the generalized Gibbs adsorption equation. By combining the bulk correlation length with the curvature-dependent interfacial tension between a s…
Lanthanides can contribute a large anomalous component to X-ray scattering when present and ordered in a target crystal. This large anomalous signal is a useful source of phase information in X-ray crystallographic studies of biological macromolecules. Thiol-reactive lanthanide chelates were tested as a means of incor…
The final step of NAD+ biosynthesis includes an amide transfer to nicotinic acid adenine dinucleotide (NaAD) catalyzed by NAD+ synthetase. This enzyme was co-crystallized in microgravity with natural substrates NaAD and ATP at pH 8.5. The crystal was exposed to ammonium ions, synchrotron diffraction data were collecte…
Dendritic Ru-BINAP catalysts functionalized with alkyl chain at the periphery together with organic binary solvent system that exhibited phase separation induced by addition of a little water have been employed for asymmetric hydrogenation, leading to high catalytic activity and enantioselectivity as well as facile ca…