Time-dependent variational method for sine-Gordon quantum field theory

The sine-Gordon model in 1+1 dimensions is studied within the Schrödinger framework for field theory. In particular we evaluate the effective potential and examine the finiteness ofm(t), the soliton mass, for allt.     

Use of novel carbon-nanofiber-doped carbon liquid crystals as suitable adsorbents for hydrogen storage

Over the last few years a number of groups have been exploring the possibilities and limitations associated with using adsorption on newly developed materials for the storage of hydrogen. Here we report the results of hydrogen adsorption investigations on a newly synthesized form of carbon nanofiber-doped carbon liquid crystals. This material shows a marked increase in specific surface area upon activation with water vapor, leading to activated samples that are capable of adsorbing hydrogen upto 3.5% by weight at 77.3 K, at moderate pressures. The possibility of higher adsorption (6.5 wt.%) in these materials is also discussed. PACS 68.43.-h; 68.43.De; 68.60.-p     

Gases Do not adsorb on the interstitial channels of closed-ended single-walled carbon nanotube bundles

We have experimentally determined the binding energies of Xe, CH4, and Ne on samples of closed-ended single-wall nanotube (SWNT) bundles. We find values for these quantities which are larger by approximately 75% on the SWNT samples than the values found for the same adsorbates on planar graphite. We have also determined the monolayer capacity of a SWNT sample using Xe and Ne adsorption. A comparison of all of our results leads us to conclude that none of the gases studied adsorb on the interstitial channels in the SWNT bundles.     

Aqueous Polymerization on Clay Surface. 2. The Polymerization of Methyl Methacrylate on Hydrogen Bentonite: Effect of Monomer Concentration and Temperature

Aqueous free radical polymerizations of methyl methacrylate with the hydrogen bentonite/ethanol system have been accomplished with less transfer to monomer in spite of high monomer concentrations and temperature. The overall initial rate has a first-order dependence on monomer. It is proposed that initiation does not occur in the aqueous phase. The apparent activation energy of 15 kcal/mol corroborates a twofold increase in rate for a 10°C rise in temperature. The frequency of bimolecular termination is quite small as is evident from k_p ² /k_t, values at various temperatures.     

Photoconducting nanocrystalline lead sulphide thin films obtained by chemical bath deposition

A chemical bath deposition method of preparing photoconducting nanocrystalline lead sulphide (PbS) thin films at room temperature (RT) is described. The aqueous bath of lead acetate, thiourea, and ammonium hydroxide produce films of about 100?nm thicknesses in 45?minutes. X-ray diffraction (XRD) studies show that these films are nanocrystalline cubic PbS with 10?nm crystallite size. Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) revealed that the films consist of spherical grains of sizes 100 to 200?nm. The transmission spectra of the films show onset of absorption edge around 850?nm and the bandgap is around 1.65?eV. The films are p-type with dark conductivity of 2.5×10^?3?S/cm and mobility of 0.07?cm²/V?s. The photosensitivity is 6–7 for an illumination of 80?mW/cm² from a halogen lamp (50?W, 12?V). Transient photoconductivity measurements reveal short and long life times of minority carriers. Thermoelectric and photothermoelectric studies show that photoconductivity in these films is mainly due to photogenerated majority carriers.     

Structural inhomogeneity and piezoelectric enhancement in ZnO nanobelts

In this work, piezoelectricity of individual ZnO nanobelts grown along the [0?1????0] direction is studied using piezoresponse force microscopy (PFM). It is found that the effective piezoelectric coefficient of these NBs, $d_{33}^{\mathrm{eff}}$ , is increasing from 2.7?pm/V at 30?kHz to 44?pm/V at 150?kHz. The results were explained by the Debye model, where structural inhomogeneity in our NBs was shown to be responsible for piezoelectric enhancement.