Materials Literature
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We derive an approximate solution for the Laplace transform of the time-dependent diffusion coefficient, D(t), of a molecule diffusing in a periodic porous material. In our model, the material is represented by a simple cubic lattice of identical cubic cavities filled with a solvent and connected by small circular ape…
A review is given of ceramic and single‐crystal thin film ferroelectric oxides, emphasizing perovskite phases, together with some new developments on hafnia films. It is shown that single‐crystal barium titanate films behave as bulk down to at least 77 nm, with no finite size effects, no phase transition temperature s…
Liquid‐phased polyaluminasilazanes were synthesized by simply reacting a liquid polyureasilazane with aluminum isopropoxide. The reaction was studied by Fourier‐transform infrared spectrometry (FTIR) and mass spectroscopy. The resultant polyaluminasilazanes were then pyrolysized to form amorphous SiAlCN ceramics at 10…
Efficient upconversion luminescence has been observed from CdSe nanoparticles ranging in size from 2.5 to 6 nm. The upconversion luminescence exhibits a near-quadratic laser power dependence. Emissions from both excitons and trap states are observed in the upconversion and photoluminescence spectra, and in the upconve…
High-pressure X-ray diffraction, Mössbauer, and Raman studies in the antiferromagnetic insulators R FeO 3 orthorhombic perovskites ( R = Pr, Eu, Lu) disclose an unusual phenomena of a reversible first-order isostructural phase transition around 50 GPa concurring with an abrupt ∼ 5% volume decrease. It is shown experim…
Metal nanoparticle nanotubes (NPNTs) have been introduced by us as a new class of template-synthesized, nanoparticle-based nanotubes possessing unique features such as room-temperature preparation, highly corrugated wall structure, electrical conductivity, mechanical stability, and defined optical absorbance. The nano…
A design and processing approach to fabricate ceramic laminates with high mechanical reliability, i.e., high failure resistance, limited strength scatter, and increased damage tolerance is presented in this paper. Different ceramic layers are stacked together to develop a specific residual stress profile after sinteri…
Functionalized polymer nanoparticles have been synthesized through an intramolecular cross-linking reaction with polystyrene as the backbone and an amino group as the functional moiety. The intramolecular cross-linking reaction was performed under ultradilute conditions, and the cross-linked polymers were characterize…
Ultrafast photoelectric effects have been observed in La0.7Sr0.3MnO3∕Si p-n junctions fabricated by laser molecular-beam epitaxy. The rise time was ∼210ps and the full width at half-maximum was ∼650ps for the photovoltaic pulse when the junction was irradiated by a 1064nm laser pulse of 25ps duration. The photovoltaic…
We report the low-temperature (∼150°C) fabrication of n-ZnO:Al∕p-SiC(4H) heterojunction light-emitting diodes by filtered cathodic vacuum arc technique. Diodelike rectifying current-voltage characteristics, with turn-on voltage of ∼3.8V and low reverse leakage current of <10−2μA, were measured at room temperatu…
We numerically investigate the competition between phase separation and dynamical arrest in a colloidal system interacting via a short-ranged attractive potential. Equilibrium fluid configurations are quenched at two different temperatures below the critical temperature and followed during their time evolution. At the…
We report the synthesis of nitric oxide-releasing gold nanoparticles formed by place-exchange reaction of hexanethiol monolayer-protected clusters with diamine nitric oxide donor precursor molecules, which are subsequently converted to N-diazeniumdiolate NO donors. The nitric oxide release from the N-diazeniumdiolate-…
Densely packed exfoliated nanosheet films such as Ti0.91O2, Ti0.8M0.2O2 (M = Co, Ni), Ti0.6Fe0.4O2, and Ca2Nb3O10 on solid substrates were prepared by the LB transfer method without any amphiphilic additives at the air-water interface. Nanosheet crystallites covered nearly 95% on the solid surface with minimum overlap…
We report on the order-to-order transitions of lyotropic liquid crystals formed by self-assembled monogylcerides and water in the presence of polysaccharides of various molecular weights. The phase diagram of monoglyceride-water-polysaccharide systems, their morphology, and the topology of liquid crystalline structure…
Fluorescence switching: Multimetallic fluorescent macrocycles aggregate into supramolecular assemblies on changing the solvent from THF to CH2Cl2. Coordinating bases (e.g., pyridine) cause deaggregation of these assemblies and result in a large enhancement of the fluorescence (see schematic representation of the organ…
A molecular triad consisting of a porphyrin (P) covalently linked to two photochromes-one from the dihydroindolizine family (DHI) and one from the dihydropyrene family (DHP)-has been synthesized and found to act as either a molecular AND logic gate or an INHIBIT gate, depending on the inputs and initial state of the p…
Fabrication of honeycomb patterned films from our synthesized amphiphilic dendronized block copolymer by "on-solid surface spreading" method and "on-water spreading" method was reported for the first time in this paper. The comparison of the two methods indicated honeycomb-patterned films with smaller size, and larger…
Strong angle-dependent intensity variations of the Fermi-level feature are observed in 4d - 4f resonant photoemission spectra of CePd$_3$(111), that reveal the periodicity of the lattice and largest intensity close to the Gamma points of the surface Brillouin zone. In the framework of a simplified periodic Anderson mo…
We report a ^{11}B NMR measurement on the recently discovered superconductor Li_2Pd_3B. The nuclear spin lattice relaxation rate 1/T_1 shows a well-defined coherence peak just below T_c (H=1.46 T)=5.7 K, and the spin susceptibility measured by the Knight shift also decreases below T_c. These results indicate that the…
Based on a model of the melting of Grain Boundary (GB), we discuss the possibility of the existence of superheated GB state. A Molecular Dynamics simulation presented here shows that the superheated GB state can realized in the high symmetric tilt GB. Whether the sizes of liquid nuclei exceed a critical size determine…