Frequency dependence of the nonlinear dielectric effect in diluted dipolar solutions

The nonlinear dielectric relaxation in dilute solutions of strongly polar molecules (4,4′-n-hexylcyanobiphenyl) in nonpolar medium (benzene) has been investigated. The nonlinear dielectric increment, induced by a d.c. electric field of high intensity (Eo ≈ 10⁷ V/m), was detected with an a.c. field of small intensity and variable frequency (1 MHz-3 GHz). The relaxational behavior of the increment is discussed in the framework of the theory proposed by Coffey et al.     

Study of the effect of γ-absorbed dose on degradation of polypropylene/starch-filled polymer containing photo-initiators by spectroscopic methods

γ irradiated samples containing photo-initiators (PIs) with and without corn starch at 0–60 kGy were studied by UV spectrophotometer and FTIR. A linear decrease in the wavelength of absorbance maximum of each aromatic PI is observed by increase in the dose. The presence of starch in the sample caused a fluctuation of the absorptions. An increase in carbonyl formation due to the effect of a PI was detected. Ferric stearate and Irgacure 184 showed the highest and lowest effect respectively.     

Influence of substrate temperature on the texture of barium ferrite film by magnetron sputtering

Barium ferrite thin films have been prepared by radio frequency magnetron sputtering on a sapphire (0 0 1) substrate at substrate temperature of 500 °C and 650 °C, respectively. The films were further annealed in air at 1000 °C for 5 h. X-ray diffraction shows that the films at the lower substrate temperatures have a good epitaxial relation with respect to the substrate, while the samples under the higher substrate temperatures have (1 0 9) planes parallel to the substrate. The remanence ratio decreases from 0.82 to 0.47 when the substrate temperature is increased. We attribute the variation of the growth direction to the enhanced vertical mobility of the deposited atoms when the substrate temperature is increased.     

Formation of borate zinc (ZnB4O7) nanotubes

The nanotubes of zinc borate (ZnB₄O₇) were first synthesized by simple sintering of mixed powders contained Zn nanoparticles and B₂O₃ in the presence of Ag catalysts in argon gas. The nanotubes of ZnB₄O₇ have a diameter of several tens of nanometers and a length of several tens of micrometers. The curved-sheet quasi-template growth mechanism for the formation of ZnB₄O₇ nanotubes was discussed. X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and transmission electron microscopy (TEM) analyses demonstrated the ZnB₄O₇ nanostructures and morphology.     

Lipschitz continuity of refinable functions on the Heisenberg group

In this paper, the Lipschitz continuity of refinable functions related to the general acceptable dilations on the Heisenberg group will be investigated in terms of the uniform joint spectral radius. We also give an investigation of the refinable functions in the generalized Lipschitz spaces related to a kind of special acceptable dilations.     

Steiner Minimal Trees in Rectilinear and Octilinear Planes

This paper considers the Steiner Minimal Tree （SMT） problem in the rectilinear and octilinear planes. The study is motivated by the physical design of VLSI： The rectilinear case corresponds to the currently used M-architecture, which uses either horizontal or vertical routing, while the octilinear case corresponds to a new routing technique, X-architecture, that is based on the pervasive use of diagonal directions. The experimental studies show that the X-architecture demonstrates a length reduction of more than 10-20%. In this paper, we make a theoretical study on the lengths of SMTs in these two planes. Our mathematical analysis confirms that the length reduction is significant as the previous experimental studies claimed, but the reduction for three points is not as significant as for two points. We also obtain the lower and upper bounds on the expected lengths of SMTs in these two planes for arbitrary number of points.     

An exploratory study of the effects of the dielectric-barrier-discharge surface pre-treatment on the self-assembly processes of a (3-Aminopropyl) trimethoxysilane on glass substrates

X-ray photoelectron spectrometry (XPS), Fourier transform infrared spectrometry (FTIR), secondary-ion-mass spectrometry (SIMS) and contact angle measurement have been used in study of the enhancement effect of substrate pre-treatment by dielectric-barrier-discharge (DBD) for the self-assembly of a (3-Aminopropyl) trimethoxysilane (APTS) on glass substrates. In results, the concentration of the APTS molecules self-assembled on the surfaces of both the acetone-washed and the DBD-treated substrates were more than three times of that on the as-supplied substrate. Meanwhile, the self-assembly (SA) layers grown on the DBD-treated substrates have the best quality compared to those grown on the substrates pre-treated in other ways in terms of the silane-substrate bonding and the order of arrangement of the silane molecules.