Chiral recognition ability of oligopeptide derivatives consisting of glutamyl residues

The effect of the constituting amino acid residue [Glu(OBzl)] number on the chiral recognition ability was investigated. Chiral recognition sites were prepared from oligopeptide derivatives (constituting amino acid residue number = three–five) by adopting alternative molecular imprinting. It was made clear that with a constituting amino acid residue number of four, the tetrapeptide derivative of Glu(OBzl) is the best candidate material to generate a chiral recognition site among eight types of oligopeptide derivatives in the study. The affinity constant between Ac‐L ‐Trp and a chiral recognition site ranged from 3.4 × 10³ to 1.08 × 10⁴ mol^?1 dm³, depending on the number of Glu(OBzl) residues in an oligopeptide derivative. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1302–1309, 2005     

Tribological Characteristics of SiC Ceramics in High-Temperature and High-Pressure Water

The effects of temperature and sliding speed on the tribological behavior of a SiC ceramic by sliding on the same material in deoxygenated water were investigated from room temperature to 300°C under the corresponding saturated vapor pressures. The friction coefficient and specific wear rates of both plates and disks increased at elevated temperatures at all sliding speeds, but decreased with increasing sliding speed at 120° and 300°C. Fine mirrorlike worn surfaces were observed without wear debris under all sliding conditions. The wear mechanism appears to consist of hydrothermal oxidation of SiC and dissolution of reaction products such as silica.     

Dependence of tunneling current through a single molecule of phenylene oligomers on the molecular length

The electrical properties of single phenylene oligomers were studied in terms of the dependence of the tunneling current on the length of the oligomers using self-assembling techniques and scanning tunneling microscopy (STM). It is important to isolate single molecules in an insulating matrix for the measurement of the conductivity of the single molecule. We demonstrate here a novel self-assembled monolayer (SAM) matrix appropriate for isolation of the single molecules. A bicyclo[2.2.2]octane derivative was used for a SAM matrix, in which the single molecules were inserted at molecular lattice defects. The isolated single molecules of phenylene oligomers inserted in the SAM matrix were observed as protrusions in STM topography using a constant current mode. We measured the topographic heights of the molecular protrusions using STM and estimated the decay constant, beta, of the tunneling current through the single phenylene oligomers using a bilayer tunnel junction model.     

Improved sublimation growth of single crystals of thiophene/phenylene co-oligomers

We have improved the sublimation recrystallization method using a handmade sublimation apparatus and optimizing various physical conditions. The improved apparatus comprises two closely aligned heaters and enables us to grow the large thiophene/phenylene co-oligomer (TPCO) crystals of high quality. We found it essential and effective for the crystal growth to adjust temperatures of these heaters and their temperature difference of ca. 40-50 °C. We fabricated organic field effect transistor (OFET) devices with the resulting crystals of a TPCO. Those devices show the p-type FET characteristics. The field effect mobilities increased with smaller thicknesses of the crystals; the maximum mobility recorded was 0.021 cm²/Vs.     

Size dependence of THz region dielectric properties for barium titanate fine particles

Barium titanate (BaTiO₃) crystallites with various particle sizes from 22 to 500 nm were prepared by the two-step thermal decomposition method of barium titanyl oxalate. Various characterizations revealed that these particles were impurity-free, defect-free, dense BaTiO₃ particles. The powder dielectric measurement clarified that the dielectric constant of BaTiO₃ particles with a size of around 58 nm exhibited a maximum of over 15,000. To explain this size dependence, the THz region dielectric properties of BaTiO₃ fine particles, especially Slater mode frequency, were measured using the far infrared (FIR) reflection method. As the result, the lowest Slater mode frequency was obtained at 58 nm. This tendency was completely consistent with particle size dependence of the dielectric constant.     

Development of µGC (micro gas chromatography) with high performance micromachined chip column

A micro gas chromatography (µGC) instrument applying a high performance chip column fabricated on a silicon wafer was developed. Experimental results of the chip column and protyping of a µGC instrument are described. Approximately 35 000 theoretical plates were generated with the chip column coated liquid phase (5% phenyl-/95% dimethyl-polysiloxane). The theoretical plates of the chip column were close to those of the capillary column. Experimental minimum height equivalent to a theoretical plate (HETP, H_min) of the chip column was 1.2 times higher than the calculated H_min. A prototype µGC applying the chip column was developed. The µGC generated approximately 35 000 theoretical plates, similar to the theoretical plates obtained by a commercial GC instrument. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于4次线性微分方程的雷电冲击试验波形分析

当冲击试验电压高时,冲击试验电压的波形叠加过冲和振荡。这是由于冲击试验回路的残余电感、被试设备的大杂散电容或二者共同作用产生的。文章用4次微分方程式对振荡冲击试验的等值回路进行了分析,结果表明,波形可分为非振荡波头、振荡波头、非极性反转波尾、非振荡的极性反转波尾和振荡极性反转波尾5个部分。非振荡的极性反转波尾和振荡极性反转波尾的产生原理是不同的。波形的高频分量定义为振荡波形,非振荡波形是不含振荡波形成份的波形。文章的研究结果是后者的产生原因和等值电阻、等值电感的关系以及4次方程的根有关。文章给出了它们之间的关系。     

High-voltage testing on UHV equipment: Overshoot and base curve for oscillating lightning impulse

As the higher impulse testing voltage, residual inductance of the test circuit or the stray capacitance of the test object increases with size. This means that the overshoot superposed on standard lightning impulse voltage would not be neglected because of its larger value during the lightning test. This paper describes the analysis of overshoot and oscillation based on the equivalent circuit containing a residual inductance. The waveform parameters such as relative overshoot magnitude, oscillation frequency are also derived to evaluate the influence of the residual inductance in the impulse testing circuit. The oscillating impulse waveform is related to the base curve of the standard lightning impulse. Furthermore, the base curve for oscillating impulse is proposed by the analysis. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Noncorrosive separator materials for electric double layer capacitor

The paper evaluates noncorrosive and inexpensive materials, namely polypropylene sheet, fiberglass, and glass wool, as potential separator materials for electric double‐layer capacitor (EDLC) application. Using these materials as separators and the same activated carbon electrodes, properties of two‐electrode capacitors filled with aqueous sulfuric acid (H₂SO₄) were investigated by cyclic voltammetry (CV) as well as galvanostatic and electrochemical impedance spectroscopy (EIS) measurements. Performance comparison of the tested capacitors with an identical capacitor with conventional cellulose separator was also carried out. As a benchmark, the noncorrosive‐separator‐based capacitors demonstrate comparable power and energy densities to those of a cellulose separator, with the highest specific capacitance of 131 F/g and lowest equivalent series resistance of 13 Ω for the glass wool separator. Application of such noncorrosive separators may realize the utilization of high‐concentration aqueous electrolytes, leading to higher rating EDLCs at lower cost compared to organic‐solution‐based capacitors. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.