Materials Literature
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High-resolution angle-resolved photoemission data show that a metal-insulator Mott transition occurs at the surface of the quasi-two-dimensional compound 1T-TaSe2. The transition is driven by the narrowing of the Ta 5d band induced by a temperature-dependent modulation of the atomic positions. A dynamical mean-field t…
In a series of heterodinuclear complexes in which a Pt(PPh3)2(catecholate) chromophore is covalently linked to a lanthanide tris(diketonate) unit, sensitised near-IR emission from Yb(III), Nd(III) and Er(III) occurs on excitation of the Pt(II) chromophore at 520 nm.
The use of a combination of tunneling and optical spectroscopy to investigate the size and shape-dependent level structure and single-electron charging phenomena in semiconductor nanocrystals is reviewed. The artificial atom character of semiconductor nanocrystal quantum dots is manifested in both the discrete level s…
Hydrogen is a ubiquitous impurity in diamond but in contrast to other group IV materials the microscopic structure adopted in bulk material has largely remained elusive. It has therefore been the role of modelling to predict the properties of H in bulk diamond, as well as the interactions with impurities and other def…
The magnetic properties of $R{\mathrm{Te}}_{3}$ $(R=\mathrm{Ce},$ Pr, Nd, Gd, Dy), which has a structure consisting of the alternate stacking of one $R\mathrm{Te}$ layer and two Te layers, were investigated using magnetization and electrical resistivity measurements. The magnetic transition temperatures were found at…
We report on a detailed study of the inversion of triglyceride oil−water emulsions stabilized solely by nanoparticles of silica. The majority of the data refers to pure tricaprylin, although similar findings are observed with the commercial analogue Miglyol 812. The effects of initial particle location, oil:water rati…
Two new compounds of the Bi/Ca/Co/O and Bi(Pb)/Ca/Co/O systems have been prepared. Their structure is built up from the intergrowth of four rock-salt-type layers and one [CoO 2 ] hexagonal layer. Both cobaltites exhibit large thermopower values ( S 300 K ∼ 140 µV K −1 ), low resistivity values (ρ 300 K = 40–60 mΩ cm)…
Our first-principles calculations demonstrate that ${\rm C}_{60-n}{\rm B}_{n}$ and ${\rm C}_{60-m}{\rm N}_{m}$ molecules can be engineered as the acceptors and donors, respectively, which are needed for molecular electronics, by properly controlling the number $n$ and $m$ of the substitutional dopants in ${\rm C}_{60}…
Based on a previously proposed thermodynamic analysis, [C. Cheng, W. H. Huang, and H. J. Li, Phys. Rev. B $63,$ 153202 (2001)] we study the relative stabilities of five Si phases under uniaxial compression using ab initio methods. The five phases are diamond, $\ensuremath{\beta}\mathrm{Sn},$ simple-hexagonal (sh), sim…
We investigate the $E_g \otimes e_g$ Jahn-Teller system for the purpose to reveal the nature of quantum chaos in crystals. This system simulates the interaction between the nuclear vibrational modes and the electronic motion in non-Kramers doublets for multiplets of transition-metal ions. Inclusion of the anharmonic p…
The sodium-cobalt oxide NaxCoO2+d is a promising candidate for thermoelectric applications since it may possess simultaneously large thermoelectric power and low resistivity. It is difficult to understand the simultaneous appearance of the two properties within the framework of conventional one-electron models. It has…
Experimental observations of the change in the polarization charge of pyroelectric crystals of LiNbO3, LiTaO3 and CsNO3, as the temperature of the crystal is changed from about 300K to a lower limit of 4.2K, are described. It was found that the rate of change of the polarization charge slowed down considerably and, pe…
New lanthanide-transition-metal (Ln-M) compounds were prepared and the structural relationships of the metal combinations were discerned. Numerous compounds derived from divalent or trivalent lanthanides and from transition metals in groups 7-11 were isolated. Three different types of interactions were observed: (1).…
In many compounds the broadband emission of Eu 2+ and Yb 2+ is subject to a very large (0.6–1.2 eV) Stokes shift and it behaves peculiarly with temperature change. Conduction band states of the host compound are involved in this ‘anomalous’ emission. Cases of anomalous emission are identified and the conditions for it…
Millimeter-long and well-aligned single-walled carbon nanotubes (SWNTs) have been produced on silica/silicon surfaces using the carbon monoxide chemical vapor deposition (CO-CVD) method. The orientation of the nanotube arrays can be well-controlled by the gas flow during the growth. The majority of the orientated SWNT…
We report a method to make crystalline silver nanowires in water, in the absence of a surfactant or polymer to direct nanoparticle growth, and without externally added seed crystallites. The reaction is one in which silver salt is reduced to silver metal, at 100 °C, by sodium citrate, in the presence of NaOH. Hydroxid…
Noble metal particles have long fascinated scientists because of their intense color, which led to their application in stained glass windows as early as the Middle Ages. The recent resurrection of colloidal and cluster chemistry has brought about the strive for new materials that allow a bottoms-up approach of buildi…
Abstract The decomposition of wood and leaf of eight species in air atmosphere is examined by nonisothermal means with linear temperature programming, and a simple kinetic description is developed based on the experimental results and integral analysis method. The relation between the apparent activation energy E and…
Abstract Waterborne polyurethanes were prepared by polyaddition reaction using isophorone diisocyanate, dimethylol propionic acid, various polyols with a fixed molecular weight ( M n = about 2000), ethylene diamine as a chain extender, and triethylamine as a neutralization agent. Three types of polyols such as (1) sol…
Abstract The graft copolymerization of styrene and methyl methacrylate onto natural rubber latex was studied under various reaction conditions using a cumene hydroperoxide redox initiator. The monomer conversion, graft copolymer compositions, and grafting efficiency were determined. The synthesized graft copolymers we…