Materials Literature
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The reverse Monte Carlo (RMC) modelling method, although initially developed for interpreting structural data from liquids and amorphous materials, has been extensively applied to similar data from crystalline systems. This has been especially beneficial for materials which display a large amount of disorder. The work…
Here, we report the role of crystal structure and crystal size on the photoluminescence properties of Ce3+ ions in Y2SiO5 nanocrystals. The emission at 430 nm (5d1 --> 4f1) and lifetime of the excited state of Ce3+ ion doped Y2SiO5 nanocrystals are found to be sensitive to the crystal structure, crystal size, and dopa…
A model of silica glass consisting of a fully connected corner-sharing network of SiO 4 tetrahedra is refined using neutron diffraction data and reverse Monte Carlo modelling. This model is then used to investigate optimal inter-tetrahedral Si–O–Si bond angle distributions. The distribution which is most consistent wi…
The local structure of nanoparticles can be determined by a direct interpretation of the first peaks observed in the radial distribution function obtained from powder diffraction data measured to high Q values. Single peak fits to these maxima yield the mean distances and width of the distribution in the first few nei…
The synthesis of porous aminopropylsilsesquioxane (APSS) has been achieved with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM(+)PF(6-)) ionic liquid (IL) as a template solvent by a nonhydrolytic sol-gel method of 3-aminopropyltrimethoxysilane under mild temperature. By the alteration of the amount of IL or the…
Reaction of equimolar amounts of AgCN and PCy3 gave the polymer [(Cy3P)Ag(NCAgCN)]infinity (1), whereas employment of excess PCy3 yielded the discrete compound [(Cy3P)2Ag(NCAgCN)] (2). Reacting bis(dicyclohexylphosphino)methane (dcpm) with AgCN in 1:1 and 1:2 molar ratios gave two crystalline forms, namely [Ag2(mu-dcp…
The total structure factors, S ( Q ), obtained from high-energy x-ray and neutron diffraction measurements on vitreous SiO 2 (v-SiO 2 ) and vitreous GeO 2 (v-GeO 2 ) have been analysed by the reverse Monte Carlo (RMC) modelling technique to generate a three-dimensional structural model. The bond angle distributions an…
A variety of novel opaque, white polymers ranging from rubbery materials to tough and rigid plastics have been prepared by the thermal polymerization at 85-160 degrees C of varying amounts of 87% conjugated linseed oil, styrene, and divinylbenzene. Gelation of the reactants typically occurs at temperatures higher than…
Earlier studies have shown that the most stable structures for (ZnS)n clusters with n = 10-47 are hollow polyhedral clusters ("bubbles"). We report a detailed study of larger clusters, where n = 50, 60, 70, and 80, for which onionlike or "double bubble" structures are predicted. We report calculations of the vibration…
We propose a one-step interface reaction for the direct synthesis of hexagonally arranged spherical silver nanoparticles under microwave-assisted solvothermal conditions without the requirement of the presynthesis of uniform silver nanoparticles or special precursors and the technique of size-selective precipitation.…
Diatoms are one of the most important constituents of phytoplankton communities in aquatic environments, but in spite of this, only recently have large-scale diatom-sequencing projects been undertaken. With the genome of the centric species Thalassiosira pseudonana available since mid-2004, accumulating sequence infor…
Nanosized sulfated zirconia with Brønsted acidic sites has been prepared by a simple calcination in the absence of any solvent. XRD patterns reveal that the sulfated zirconia mainly consists of tetragonal crystalline zirconia with average size of about 7 nm, which is further confirmed by TEM images. N2 adsorption data…
Injection-molded composite materials as fabricated from chopped glass fiber and poly(trimethylene terephthalate), PTT, are evaluated through physicomechanical and thermomechanical analysis. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to measure the thermal properties of the…
ZnO films were grown on polycrystalline Zn foil by cathodic electrodeposition in an aqueous zinc chloride/calcium chloride solution at 80 °C. Variation in the electrochemical parameters resulted in a variation in growth morphology from 1D (nanorods), 2D ('nanoplates') to 3D crystal growth. An as-received or mechanical…
The basic reverse Monte Carlo algorithm, as applied primarily for the study of disordered systems, is introduced, using an example of a new reverse Monte Carlo computer code. RMC++ is a new implementation of the RMC algorithm in C++. Its main purpose is to provide the community with a fast, flexible and documented cod…
To optimize the properties of carbon nanotube−polymer composites, it is important to control nanotube dispersion and alignment. One way to achieve such control is by growing homogeneous, well-aligned arrays of carbon nanotubes using chemical vapor deposition and infiltrating polymer or monomer into the arrays, followe…
We show that subwavelength imaging by negative index materials (NIM), related to their "soft" electromagnetic response, is very (and non trivially) sensitive to the surface properties. A minute deviation of dielectric permittivity epsilon or magnetic permeability mu from the ideal values epsilon = mu = -1 in thin surf…
Stable suspensions of tunicate cellulose microfibrils were prepared by acid hydrolysis of the cellulosic mantles of tunicin. They formed a chiral nematic phase above a critical concentration. External magnetic fields were applied to the chiral nematic phase in two different manners to control its phase structure. (i)…
Synthesis of branched gold nanocrystals by a seeding growth approach is described. In this process, HAuCl4 aqueous solution was supplied stepwise to grow the gold seeds (approximately 2.5 nm) into larger nanoparticles with a highly faceted particle structure (approximately 15-20 nm in diameter). Sodium dodecyl sulfate…
The thermal decomposition of hydrogen peroxide, H(2)O(2), was determined in aqueous suspensions of SiO(2), Al(2)O(3), TiO(2), CeO(2), and ZrO(2) nanometer-sized particles. First-order kinetics were observed for the decomposition in all cases. Temperature dependence studies found that the activation energy was 42 +/- 5…