Solid Polymer Electrolytes Based on Poly(1,3-diacetyl-4-imidazolin-2-one)

Summary Solid polymer electrolytes composed of a homopolymer (poly(AcIM)) of 1,3-diacetyl-1,4-imidazolin-2-one (AcIM) and lithium bis(trifluoromethanesulfonimide) (LiTFSI) or of copolymers (poly(AcIM/VC)) of AcIM with vinylene carbonate (VC) and LiTFSI were prepared and their ionic conductivities and thermal properties were investigated. For the polymer electrolyte of the poly(AcIM) with LiTFSI, the highest ionic conductivity was found at the [Li]/[O] ratio of 1/3 with the values of 8.5×10^-5 S/cm at 80 °C and 1.7×10^-6 S/cm at 30 °C, respectively. In the polymer electrolyte of poly(AcIM/VC) with LiTFSI at the [Li]/[O] ratio of 1/3, the ionic conductivity increased with increasing VC unit content in the copolymers, and the highest ionic conductivity was found at the AcIM/VC ratio of 39/61 (mol%) with the values of 7.0×10^-4 S/cm at 80 °C and 6.7×10^-5 S/cm at 30 °C, respectively. This copolymer electrolyte showed a linear relationship between the ionic conductivity and the reciprocal of the temperature, indicative of the system decoupled from the segmental motion of the polymer.     

Physical and mechanical properties of poly(L‐lactic acid) nucleated by dibenzoylhydrazide compound

Benzoylhydrazide compounds were evaluated as a nucleating agent for poly(L ‐lactic acid) (PLA). From the results of the differential scanning calorimetry, octamethylenedicarboxylic dibenzoylhydrazide (OMBH) was found to be most effective for acceleration of PLA crystallization under higher cooling rate of ?50°C min^?1. PLA with OMBH of 1 wt % exhibited very short crystallization half‐time with wide range of isothermal temperature from 90 to 130°C. The molding cycle time of PLA with OMBH in injection molding was less than 3 min, and the cooling time was one‐third of ethylenebis(12‐hydroxystearylamide)/talc system as a nucleating agent. Physical and mechanical properties improved extremely, and the heat distortion temperature of 124°C, flexural modulus of 4.1 GPa, and Izod impact strength of 7.9 kJ m^?2 were achieved. This indicates that the utilization of OMBH makes it possible to extend the application range of PLA as automotive parts and electric appliances, which require higher heat resistance and stiffness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 244–250, 2007     

Effects of Glass Additions on (Zr,Sn)TiO4 for Microwave Applications

The effects of glass additions on the properties of (Zr,Sn)TiO₄ as a microwave dielectric material were investigated. The (Zr,Sn)TiO₄ ceramics with no glass addition sintered at 1360°C gave Q = 4900 and K = 37 at 7.9 GH_z. Several glasses, including SiO₂, B₂O₃, 5ZnO–2B₂O₃, and nine commercial glasses, were tested during this study. Among these glasses, (Zr,Sn)TiO₄ sintered with ZnO-B₂O₃–SiO₂ (Corning 7574) showed more than 20% higher density than that of pure (Zr,Sn)TiO₄ sintered at the same temperature. A 5-wt% addition of SiO₂, to (Zr,Sn)TiO₄, when sintered at 1200°C, gave the best Q : Q = 2700 at 9 GHz. Results of XRD analysis and scanning electron microscopy and the effect of glass content are also presented.     

Thermoelectric properties of boron-carbide thin film and thin film based thermoelectric device fabricated by intense-pulsed ion beam evaporation

Crystallized B₁₃C₂ thin films were fabricated by intense pulsed-ion beam evaporation (IBE) method. Electrical conductivity and Seebeck coefficients of the obtained films were 1×10^—4 l/Ωm and 200 μV/K at 1000 K, respectively. These values were comparable to those of bulks. For the application of the thin films, since reasonable thermoelectric (TE) properties were confirmed for the B₁₃C₂ films fabricated, we attempted to develop ’in-plane’ type TE device using B₁₃C₂ and SrB₆ as p-type and n-type elements, respectively. With applying temperature difference to the fabricated device, thermo-electromotive force and electrical power were generated from the device we made, indicating that the device worked as a TE device. To the best of our knowledge, this is the first demonstration of the TE device composed of only boron-rich solids.     

Multi-bit Sigma-Delta TDC Architecture with Improved Linearity

This paper describes the architecture and principles of operation of sigma-delta ( ΣΔ) time-to-digital converters (TDC) for high-speed I/O interface circuit test applications. In particular, we describe multi-bit ΣΔ TDC architectures; they offer good accuracy with short testing time. However, mismatches among delay cells in delay lines degrade their linearity. Here we propose two methods to improve the overall TDC linearity: a data-weighted-average (DWA) algorithm, and a self-calibration method that measures delay values using a ring oscillator circuit. Our Matlab simulation results demonstrate the effectiveness of these approaches.     

Operation of vehicles in AGV system and method for analyzing operation

It is important to discuss the behavior of traffic at merging sections for the design and realization of an automated guided vehicle system (AGVS). In this study, we deal with a merging section of the AGVS by considering the time limit for the merging of vehicles. Near the merging section, the traffic flow in one direction forms a queue to avoid collisions between vehicles. We present an improvement of the control strategy proposed in previous research. However, since it is difficult to analyze the mathematical model of the merging section, analysis can be performed only for the case in which the time limit is set to the least values. We also propose a method for analyzing the model for an arbitrary time limit by using a linear recurrence relation. We discuss quantitatively the influence of the time limit on the average queue length and the detour rate. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(1): 56–68, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21190     

Pressure drop and heat transferin spanwise-periodic fluted channels

We have conducted numerical studies on the three-dimensional laminar forced convection heat transfer in a channel with spanwise-periodic fluted parts by applying the spectral element and finite difference methods. The flow field is assumed to be fully developed, while the temperature field is supposed to be developing under the fully developed velocity profile. The temperature on the plate surface is kept constant. Pressure drop, heat transfer, and correlation between them are investigated for varying configurations of the fluted channel. The nondimensional formulas with regard to the pressure drop and Nusselt number are derived for the parameters of the channel configurations. Channel efficiency, which is defined as the ratio of the heat transfer enhancement to the increase of pressure drop compared with the parallel plate channel, is studied according to the nondimensional formulas to clarify the optimum parameter range of channel configurations.     

Green synthesis of mesoporous hematite (α-Fe2O3) nanoparticles and their photocatalytic activity

A green synthesis method for the preparation of mesoporous α-Fe₂O₃ nanoparticles has been developed using the extract of green tea (camellia sinensis) leaves. This simple and one-step method can suitably be scaled up for large-scale synthesis. The as-prepared mesoporous nanoparticles were characterized by SEM, TEM, XRD, XPS, Raman, UV–visible spectroscopy and N₂ adsorption analysis. The nanoparticles were highly pure and well crystallized with an average particle size of 60 nm. The photocatalytic activity of nanoparticles was evaluated by the amount of hydroxyl radical formation under visible light irradiation detected by fluorescence spectroscopy. The as-prepared α-Fe₂O₃ showed two times higher activity than commercial α-Fe₂O₃ in term of hydroxyl radical formation and enhanced performance in a photoelectrochemical cell. Also, a plausible mechanism for the formation of mesoporous α-Fe₂O₃ has been suggested.