Plasmonic Fano resonance and dip of Au-SiO2-Au nanomatryoshka

This study theoretically investigates Fano resonances and dips of an Au-SiO₂-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green''s functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes.     

Using ADABOOST and Rough Set Theory for Predicting Debris Flow Disaster

Debris flow resulting from typhoons, heavy rainfall, tsunamis or other natural disasters is a matter of particular importance to Taiwan owing to the country’s unique geographical environment and exacerbated by poor slope management and global warming. With regard to these types of natural occurrences, recent global events have attracted the attention of experts in various fields, such as civil engineering, environmental engineering and information management. These experts have developed several techniques to study the various factors of debris flow. The ADABOOST and rough set theory (RST) are two emerging methods with regard to classification and rule provision. The ADABOOST, an adaptive boosting machine learning algorithm, uses very little memory during computation and can obtain robust classification results. RST is able to deal with uncertainties and vague information in generating rules for decision makers. Thus, this study develops an ADARST model which uses the unique strengths of the ADABOOST and RST in classification and rule generation and applies the proposed ADARST to analyze debris flow. Specifically, data from previous studies were obtained and used for the purposes of this study. Experimental results have shown that the proposed ADARST model is able to generate better results than those in previous investigations in terms of prediction accuracy. In addition, the designed ADARST model can provide rules including forward and backward reasoning ways for decision makers. Therefore, the proposed ADARST model is shown to be an effective methodology with which to analyze debris flow.     

The spatial conservative congruence transformation for manipulator stiffness modeling with coordinate and noncoordinate bases

This paper presents systematic methods to approach the spatial conservative congruence transformation (SCCT) and applies it to the stiffness transformation and matrices of robotic systems via the strategy of changing basis. Through geometrical analysis, the realization of the Cartesian stiffness of manipulators is shown to be basis dependent. We illustrate that the SCCT is conservative as well as directly represents the spatial stiffness mapping relationship for robotic stiffness control. Examples of the serial manipulators are given to help one to better understand the source of the asymmetric 6×6 Cartesian stiffness matrix in the presence of external loads using the SCCT algorithm. The SCCT suggests an explicit and generalized stiffness transformation relationship for robotic systems. © 2005 Wiley Periodicals, Inc.     

Thickness dependent magnetic properties of BiFeO3 thin films prepared by pulsed laser deposition

BiFe_1 ? xMn_xO₃ thin films having thickness 65 and 130 nm was fabricated on LAO substrates using pulsed laser deposition technique and its structural and magnetic properties were examined. Atomic force microscopy images confirmed that, as the thickness of the films increases the particles size also increases resulting in the decrease of magnetization. The possible cause for the lowering of magnetization with film thickness was discussed. Increase of spontaneous magnetization in BiFeO₃ at room temperature was observed with Mn substitution for Fe. The blocking temperature was found to decrease with increasing film thickness.     

Structural properties and sensing characteristics of high-k Ho2O3 sensing film-based electrolyte–insulator–semiconductor

In this study, we report a Ho₂O₃ electrolyte–insulator–semiconductor (EIS) device films deposited on Si substrates through reactive sputtering. The effect of thermal annealing (700, 800, and 900 °C) on the structural and surface properties of Ho₂O₃ sensing film was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy. We found that the EIS device with a Ho₂O₃ sensing film annealed at 800 °C exhibited a higher sensitivity of ∼57 mV/pH, a lower hysteresis voltage of 2.68 mV, and a smaller drift rate of 2.83 mV h⁻¹ compared to those at other annealing conditions. This improvement can be attributed to the well-crystallized Ho₂O₃ structure and the large surface roughness.     

The effect of addition of acrylic acid and thioglycolic acid on the nanostructure and thermal stability of PMMA–montmorillonite nanocomposites

Poly(methyl methacrylate) (PMMA)/organophilic montmorillonite (OMMT) nanocomposites were synthesized by the in situ free radical bulk polymerization of methyl methacrylate. The effect of small amount of acrylic acid as the co-monomer and thioglycolic acid as the chain transfer agent on the nanostructure of these nanocomposites was investigated by X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) analyses. No reflection was discernible in the XRD patterns of all samples. In SAXS experiments, a great amount of small clay montmorillonite aggregates (less than 40 Å) were observed. The acrylic acid used as the co-monomer increased the affinity between the montmorillonite and the polymer, resulting in better dispersion of the montmorillonite particles. The glass transition temperature of the nanocomposites was evaluated by differential scanning calorimetry (DSC) and the thermal stability was investigated by thermogravimetric studies (TGA). As expected, the presence of the montmorillonite increased the glass transition temperature. The thermal stability of nanocomposites was distinctly higher than of pure PMMA and was increased by the presence of small amounts of acrylic acid as the co-monomer.     

Separation of diethylbenzene isomers by distillative freezing

Due to the close boiling points of the mixed diethylbenzene (DEB) isomers, it is rather complicated to separate them by distillation. A new separation technique, distillative freezing (DF), is successfully applied to separate p-DEB from the diethylbenzene isomers in this study. Basically, the DF process operates at a triple point condition, in which the liquid mixture is simultaneously vaporized and solidified due to the three-phase equilibrium. It results in the formation of pure crystals along with the liquid phase and vapor phase of the mixtures. The process can be continued until the liquid phase is completely eliminated and only the pure solid crystals remain in the feed. A model, whereby the DF process is simulated in a series of equilibrium stage operations, is proposed to direct the DF operation. In the model, each stage is operated under an adiabatic condition at a three-phase equilibrium. The experiments show that, in the p-DEB/m-DEB mixtures, p-DEB can be purified from 80% to 99% through several DF operations with the experimental recovery rate of p-DEB in one DF operation ranging from 58% to 77%. The unique feature of this new separation technique is that no filtration and crystal washing is required after the p-DEB crystals are obtained by DF.     

Performance approximation of re-entrant lines with unreliable exponential machines and finite buffers

In this paper, we present an approximation method to estimate the production rate of re-entrant lines with unreliable exponential machines having identical processing times, finite buffers, and last buffer first serve scheduling policy. Recursive procedures are developed and structural properties are investigated. The results show that the proposed method provides an acceptable accuracy in production rate approximation for re-entrant lines.     

Enhancing customer value through click-and-mortar e-commerce: implications for geographical market reach and customer type

Firms continue to focus more attention on how to make use of the Internet for commercial purposes. Traditional firms are integrating their existing market channels and their online presence, into what is often called click-and-mortar e-commerce. In this paper we will discuss how click-and-mortar e-commerce generates synergies and customer value, and what implications it has for the type of customers and the geographical market a firm serves. The analysis of eighteen Dutch firms from a variety of industries has the following results. First of all, click-and-mortar e-commerce is used to strengthen relations with existing customers in geographical markets where firms are already active. Secondly, click-and-mortar firms are able to serve relocating customers and re-establish contact with customers who have moved away. Thirdly, click-and-mortar e-commerce can make it easier and less costly to make a purchase within a firm’s existing market, which may have the effect of bringing in new customers in that market. Contrary to the usual expectations for e-commerce, click-and-mortar e-commerce are to a lesser extent used to penetrate new, more distant geographical markets, nationally as well as internationally. The case studies also indicate that the degree of click-and-mortar e-commerce integration influences the way in which firms exploit synergies, as well as the possibilities to target different customers and geographical markets.