A geometric method of sector decomposition

We propose a new geometric method of IR factorization in sector decomposition. The problem is converted into a set of problems in convex geometry. The latter problems are solved using algorithms in combinatorial geometry. This method provides a deterministic algorithm and never falls into an infinite loop. The number of resulting sectors depends on the algorithm of triangulation. Our test implementation shows smaller number of sectors comparing with other existing methods with iterations.     

Lateral Inhomogeneity in the Electronic Structure of a Conjugated Poly(3‐hexylthiophene) Thin Film

How annealing influences the morphology of a highly regioregular poly(3‐hexylthiophene) (RR‐P3HT) film at the substrate interface as well as the lateral inhomogeneity in the electronic structure of the film are elucidated. Whereas previous studies have reported that high‐molecular‐weight (MW) RR‐P3HT films tend to show low crystallinity even after annealing, it is found that high‐MW RR‐P3HT does show high crystallinity after annealing at high temperature for a long time. Photoemission electron microscopy (PEEM), X‐ray photoemission spectroscopy, and ultraviolet photoemission spectroscopy results clearly resolve a considerable lateral inhomogeneity in the morphology of RR‐P3HT film, which results in a variation of the electronic structure depending on the local crystallinity. The PEEM results show how annealing facilitates crystal growth in a high‐MW RR‐P3HT film.     

(p,q)-Logical completeness for output-coherent sets of (p,q)-Logical functions and an application of the set to image processing

We have previously proposed an idea of p-valued input, q-valued output threshold logic to synthesize many-valued, p-valued, logical networks, and derived the condition for (p, q)-logical completeness for the output-closed set of (p, q)-logical functions. In this paper, the condition for (p, q)-logical completeness for the output-coherent set F of (p, q)-logical functions is described, and the proof is given in almost the same way as for the output-closed set. The output-coherent set F is applied to image processing. That is, a restoration scheme is described for images to which normal random noise is added.     

Dynamic Characteristics Analysis of Two‐DOF Oscillatory Actuator and Experimental Verification of Prototype

Recently, linear oscillatory actuators have been used in a wide range of applications. In particular, small linear oscillatory actuators are expected to be used in haptic devices by being extended to provide multi‐degree‐of‐freedom motion with arbitrary acceleration. In this paper, we propose a compact two‐DOF oscillatory actuator that can move in various directions on a plane. The static and dynamic characteristics of the actuator are determined by the 3D finite element method. The effectiveness of this method is shown through a comparison of the measured results with the experimental results from a prototype. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(1): 58–65, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22312     

Asymmetric electric double layer capacitors using carbon electrodes with different pore size distributions

Asymmetric capacitors composed of carbon electrodes with different pore size distributions (PSD) were constructed in order to study the fundamental relationship between the PSD of positive and negative carbon electrodes and the performance of electric double layer capacitors. The performance of asymmetric capacitors in a non-aqueous electrolyte solution (TEMA·BF₄/PC) was found to be governed by the PSD of the carbon used in the negative electrode. Capacitance depends on the BET surface area of the negative electrode and the rate performance depends on its mesoporous surface area. These results were explained by the fact that it is more difficult to adsorb large solvated cations (TEMA⁺) in micropores (less than 2 nm wide) than in mesopores (2-50 nm wide), and that this is more difficult with a higher rate of charge-discharge.     

High-pressure viscosity prediction of di(2-ethylhexyl) phthalate and tricresyl phosphate binary mixtures using dielectric relaxation data

Dielectric permittivity and loss in di(2-ethylhexyl) phthalate and tricresyl phosphate binary mixtures were measured over a frequency range from 100 Hz to 1.5 MHz under high pressure. The mixtures showed single dielectric relaxation. The composite plots of the dielectric loss data showed one master curve and time–temperature–pressure superposition were applicable. The prediction of high-pressure viscosity was carried out from the change of dielectric relaxation time with temperature and pressure. The predicted results showed relatively good agreement with viscosity data obtained from a falling-sphere viscometer.     

Observation of the solid-state formation of a TTF–CA complex by terahertz spectroscopy

The solid-state synthesis of a tetrathiafulvalene–chloranil (TTF–CA) complex was demonstrated, and progress in the formation of the complex was monitored using a GaP Raman terahertz (THz) spectrometer. Clear transitions in the THz absorption spectra indicated that the mixture of TTF and CA became the black phase TTF–CA complex. The results of X-ray diffraction, Raman scattering, and FTIR spectra are presented as supporting evidence.     

Geometric control and tuneable pore size distribution of buckypaper and buckydiscs

The fabrication of buckypaper from unfunctionalised multi-walled carbon nanotubes (MWCNTs) without the aid of surfactants or surface modification techniques is accomplished through a novel and quick frit compression method. The dimensions can be controlled through the size of the syringe housing and the through the mass of carbon nanotubes added. Their thicknesses are typically much larger than surfactant-cast buckypaper and range from 120 μm up to 650 μm; buckypaper with thicknesses larger than 500 μm we call buckydiscs. Buckypaper and buckydiscs are mechanically robust to handle, flexible, stable in solvents and possess larger porosities than Triton-X100 cast buckypaper. They also exhibit a memory effect when bending wetted samples, returning to their former geometry on drying. Buckypaper and buckydiscs were studied by mercury intrusion porosimetry to reveal a defined distribution of mesopores and small macropores that is, along with their density and apparent free volume, dependant on the casting solvent and therefore tuneable. Moreover, the frit compression system also allows control over the 3-dimensional geometry of the buckydiscs during the casting process.     

Study on dominant mechanism of high-cycle fatigue life in 6061-T6 aluminum alloy through microanalyses of microstructurally small cracks

The mechanism controlling the fatigue life of a precipitation-hardened Al–Mg–Si alloy (6061-T6) at a high-cycle fatigue (HCF) regime of over 10⁷ cycles was investigated in detail. It was found that over 90% of the total fatigue life was occupied by the growth process of a microstructurally small crack at relatively low stress amplitude. The small crack was often found to be arrested and halted for a long period (more than 10⁶ cycles) before it began to grow again, which resulted in a significantly slow growth process. The small crack was then analyzed not only by the conventional fractography but also by the cross-sectional observation of the crack tip region using a focused ion beam and transmission electron microscopy. These observations, supplemented also by a grain orientation analysis using electron backscattered diffraction, explicitly revealed the following points: (i) the small crack growth observed on the specimen surface is primarily related to facet-type cracking that occurs exclusively at the specimen surface; (ii) the growth direction of the small crack has strong anisotropy (i.e. surface-induced growth); (iii) the facet-type cracking is related to the formation of persistent fine slip bands that accompany no structural change of the matrix. On the basis of these results, the micromechanism of small crack growth and its relation to the concept of fatigue limit at the HCF regime is discussed in detail.     

Development of fabrication process for Ag/polydiacetylene (core/shell) hybridized nanocrystals

Core/shell hybridized nanocrystals composed of Ag nanoparticle core and polydiacetylene shell were fabricated successfully by means of “co-reprecipitation/microwave irradiation method”. The hybridized nanocrystals were characterized using transmission electron microscopy (TEM) observation and UV–vis absorption spectroscopy. UV–vis spectral measurements revealed that polydiacetylene shell was the red phase while π-conjugated backbone is distorted. Detailed mechanism of formation of the red phase was discussed.