Velocity and absorption coefficient of ultrasonic waves in molten and glassy silicates and borates

The velocity and absorption coefficient of longitudinal ultrasonic waves with 5 and 10 MHz in molten and glassy silicates and borates have been measured by means of the pulse-echo method in 300 to 1600 K. The silicate and borate were Na₂O−SiO₂, K₂O−SiO₂, PbO−SiO₂, Na₂O−B₂O₃, and PbO−B₂O₃. The velocity of sound decreased with increasing temperature and decreased rapidly near the transition temperature of glasses. The product of the one-third power of velocity of sound and the molar volume of the oxide melt was constant and independent of temperature. The absorption coefficient of ultrasonic waves in the oxide melts increased with an increase in viscosity. The absorption mechanisms of ultrasonic waves and the mean free path of phonons in the oxide melts were discussed.     

60 GHz band 64 QAM/OFDM terrestrial digital broadcasting signaltransmission by using millimeter-wave self-heterodyne system

This paper describes the first time experimental studies on 60-GHz band transmissions of terrestrial digital broadcasting signals (ISDB-T) with 64-QAM modulations on coded orthogonal frequency division multiplexing (COFDM) format. It has been a very difficult experiment to accomplish because it requires very stable and low phase-noise oscillators in the millimeter-wave band. The use of our proposed millimeter-wave self-heterodyne system, overcame this problem without using a stable oscillator, and provided a bit error rate (BER) of less than 10^-6 without any forward error correction. We also discuss the relationship between the carrier-to-noise power ratio and the BER obtained, and demonstrate that the penalty of the required CNR for our experimental system is less than 1 dB compared to the results of a back-to-back BER test     

Frenkel pair accumulation induced crystallization of amorphous MgAl2O4

The epitaxial and homogeneous irradiation induced re-crystallization of amorphous MgAl₂O₄ was studied by means of continuous Frenkel pair accumulation in the molecular dynamics framework. Present results point out that the re-crystallization induced by Frenkel pair accumulation appears in both cases to be thermally enhanced but non diffusive. It is governed by a local rearrangement of each point defect in the homogeneous case, while spontaneous Frenkel pair recombination process in the crystalline part or at the interface drives the re-crystallization in the epitaxial case.     

Environmental stress cracking of poly(acrylonitrile-butadiene-styrene)

The environmental stress cracking (ESC) of acrylonitrile-butadiene-styrene (ABS) copolymer caused by a non-ionic surfactant (poly-oxyethylene alkylether) was studied by constant-load tensile creep tests and edge crack tension (ECT) tests. The fracture surfaces were investigated by a scanning electron microscope (SEM) and the morphology of the crack tip was investigated by a transmission electron microscope (TEM). It was found that the results of the creep tests performed in the non-ionic surfactant were very different from those performed in air. SEM images of the fracture surfaces showed that there were three different mechanisms of fracture and that specimens had a tendency to rupture by ESC when the stress was small. The results of the ECT tests and the TEM images showed that the change in the mechanism of the fracture was attributable to the change of morphology at the crack tip.     

Interface state generation mechanism in n-MOSFET's

Uniform carrier injection into the channel of n-MOSFETs generates two types of interface states, depending on the oxide electric field: One is linearly proportional to the injected electron density (Type I), while the other shows a half-power dependence (Type II). Charge-pumping measurements in the temperature range of 77K and 263K show that the type I interface states are located in the mid-gap, while the type II interface states are uniformly distributed in wide energy range. Holes generated at the gate/SiO₂ interface or in the oxide are found to be responsible for the type I interface states, while hydrogen or hydrogen compounds diffusing from the interface cause the type II interface states.     

Smoking and small, dense low-density lipoprotein particles: cross-sectional study

All forms of tobacco cause cardiovascular disease, and tobacco-related disease is a leading cause of death worldwide. Smoking oxidizes low-density lipoprotein (LDL) particles, and oxidized LDL particles are thought to play an early and critical role in atherosclerogenesis. Hyper-low-density lipoproteinemia is one of the risk factors for cardiovascular disease, but small, dense LDL particles have been associated with an increased risk for cardiovascular disease. Small, dense LDL correlates with some cardiovascular risk factors such as diabetes mellitus, hypertriglyceridemia, hypo-high-density lipoproteinemia, and hypertension. Although smoking is also a major risk factor for cardiovascular disease, the relationship between smoking and small, dense LDL particles has not been described previously. Our cross-sectional study examined this relationship in a population of 18 healthy young adult men (9 smokers and 9 never-smokers, aged 21-24 years) from the same college. Concentrations of blood lipids and the LDL migration index (LDL-MI) were examined. Although concentrations of blood lipids did not differ between smokers and never-smokers, the LDL-MI had a strong tendency to be lower in smokers. The LDL-MI is larger in the presence of a greater proportion of small, dense LDL particles. These results indicate that tobacco smoking is associated with a decrease in the proportion of small, dense LDL particles. Regardless of these surprising results, we do not recommend smoking, given that it is a major cause of cardiovascular disease.     

Orbit systematics in anisotropic Kepler problem

We revisit the Anisotropic Kepler Problem (AKP), which concerns with trajectories of an electron with anisotropic mass term in a Coulomb field. This is one of the most fundamental fields in Quantum Chaos. Nowadays various quantum systems are challenging us. Classical theories of these may have chaos. Quantum mechanics have developed from integrable cases and may have to be reformulated for such cases. AKP then serves as a suitable testing ground for quantum chaos. We first review a pioneering work by Martin Gutzwiller (J Math Phys (1977) 18:106). We shall show the systematics of the trajectories using ample figures from an extensive numerical analysis. Then we focus on the rolê of hyperbolic singularities and we comment on the approximations in an analytic formulation. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Lagrangian method for deriving electrically dual power converters applicable to nonplanar circuit topologies

This paper proposes a novel method for deriving dual converters, namely deriving current‐source converters from voltage‐source counterparts, and vice versa. The conventional derivation method is based on the transformation of circuit topology, in which series connections are converted into parallel connections, and vice versa. However, this method cannot be directly applied to nonplanar circuits because they do not allow perfect topological transformation, although many of them are known to have duals. Lagrangian dynamics does not depend on the topological relation to transform a system into another equivalent system; therefore, it possibly avoids problems related to topological transformation and may provide a universal and systematic method that can be consistently applied to nonplanar circuits. This paper discusses the derivation of duals using Lagrangian dynamics. Along with the theory, this paper presents two examples of Lagrangian derivation of duals. One derives a dual of a planar circuit, to which the topological transformation is applicable. The other derives two duals of a nonplanar circuit. Consequently, these examples suggest that the proposed method is a prospective candidate for universal and systematic derivation of duals. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

工艺参数及稳定剂抗坏血酸对电沉积NiFeW合金的影响

为获得性能良好的镍铁钨合金镀层,研究了镀液pH 值、温度、电流密度、稳定剂抗坏血酸浓度对镍铁钨合金镀层成分和镀层沉积速率、显微硬度的影响。结果表明: 镀液pH 值对镀层W含量和镀层沉积速率影响较大;镀液温度对镀层沉积速率、镀层成分和镀层硬度影响均较大;随抗坏血酸浓度增加,镀层沉积速率逐渐降低,镀层表面形貌更加粗糙。在镀液pH = 4,温度60 ℃,电流密度4 A/dm2,抗坏血酸浓度3 g /L 时,镀层沉积速率和镀层的显微硬度较高,表面光亮致密,耐蚀性好。     

Electrochemical behavior of copper current collector in imidazolium-based ionic liquid electrolytes

The electrochemical behaviors of copper current collector in 1-alkyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ionic liquid electrolytes were investigated and compared with that in ethylene carbonate/dimethyl carbonate solutions. Cyclic voltammetry results showed that large oxidation–reduction current of the copper foil appeared in ethylene carbonate/dimethyl carbonate solutions, while a much smaller current in the room temperature ionic liquid electrolytes decreased gradually, indicating that the copper foil was anodically stable. Further study by X-ray photoelectron spectroscopy analysis showed that an unstable product was composed mainly of the carbonate and carbonyl species on the surface of the copper foil after the electrochemical measurement in ethylene carbonate/dimethyl carbonate solutions, leading to the dissolution of the copper foil. While a better passivating film from the reduction of the anions in the room temperature ionic liquid electrolytes covered the surface of copper foil and protected the copper foil from being oxidized even in a higher potential. These results indicate that the use of room temperature ionic liquid electrolytes can improve the stability of copper current collector in the advanced lithium ion batteries.