Thermally stable ion conductive polymer composites containing imide-anion-type zwitterions

Summary Zwitterion bearing highly dissociable imide anion (EIm5csI) was used as major component for stable polymer electrolytes. A polymerization of methyl acrylate in the presence of EIm5csI/LiTFSI mixture gave a flexible film with the ionic conductivity of 9.3×10^-6 Scm^-1 at 50 °C. Mixing of poly(lithium acrylate) and EIm5csI/LiTFSI mixture improved ionic conductivity (3.3×10^-5 Scm^-1 at room temperature), lithium transference number (0.44), and thermal stability.     

Effects of Thermal Annealing on Formation of Micro Porous Titanium Oxide by the Sol–Gel Method

We investigated the structural and optical properties of microporous titanium oxide (TiO₂) fabricated by the sol–gel method using templates of colloidal crystals with polystyrene spheres when the annealing temperature was changed between 600° and 1000°C. From X-ray diffraction patterns and SEM images, the rutile TiO₂ annealed at a high temperature did not form periodic porous bodies, while the anatase TiO₂ annealed at lower than 800°C formed periodic porous bodies. The porous TiO₂ obtained acts as an air-sphere/TiO₂ photonic crystal with an FCC structure. It is suggested that TiO₂ sol annealed at a lower temperature do not lead to phase transition from the anatase phase to the rutile phase to obtain the air-sphere/TiO₂ photonic crystal by the sol–gel method using templates of colloidal crystals.     

Phase-transformation study of metastable tetragonal zirconia powder

The rate of the transformation from the metastable tetragonal to the monoclinic phase of ZrO2 was measured in air from 850°C to 1000°C by neutron diffraction. This rate was found to be temperature dependent, and its measured values were considerably lower then those reported previously. The kinetics of this phase transformation is discussed in terms of a modified crystallite growth-martensitic transformation model' that includes the distribution of crystallite sizes.     

Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

In this article we review the fundamental properties and applications of sidewall GaAs tunnel junctions. Heavily impurity-doped GaAs epitaxial layers were prepared using molecular layer epitaxy (MLE), in which intermittent injections of precursors in ultrahigh vacuum were applied, and sidewall tunnel junctions were fabricated using a combination of device mesa wet etching of the GaAs MLE layer and low-temperature area-selective regrowth. The fabricated tunnel junctions on the GaAs sidewall with normal mesa orientation showed a record peak current density of 35 000 A cm^-2. They can potentially be used as terahertz devices such as a tunnel injection transit time effect diode or an ideal static induction transistor.     

A benefit incidence matrix for urban transport improvement

By constructing a socioeconomic model within the framework of the multiregional general equilibrium theory, this paper proposes a matrix for an urban transport improvement project that illustrates the relationship between benefit generation and incidence. On this matrix the benefit/loss associated with each sector (household, private firm, absentee landowner, public transport corporation, and government) and associated with each item (transport, land, tax, fare revenue, and project surplus/loss) are indicated clearly, so that the social efficiency and equity of the project can easily be discussed.An earlier version of this paper was presented at the 11th Pacific Conference, Singapore, July 1989.     

Expressions of vascular endothelial growth factor in nonparenchymal as well as parenchymal cells in rat liver after necrosis

Vascular endothelial growth factor (VEGF) can induce proliferation of sinusoidal endothelial cells. Its mRNA expression was increased in proliferating rat hepatocytes in primary culture. To clarify a role of VEGF in liver after necrosis, expressions of VEGF and its receptors were measured in the liver or liver cells isolated from rats after carbon tetrachloride intoxication. Hepatic VEGF mRNA expression increased later than 24 h after the intoxication and became prominent at 168 h when liver necrosis disappeared, while hepatic mRNA expressions of its receptors increased between 24 and 72 h. VEGF mRNA expression was increased in Kupffer cells, hepatic macrophages and stellate cells isolated from rats between 24 and 72 h after the intoxication and in hepatocytes at 168 h compared to those cells from normal rats. Immunohistochemical VEGF stains were comparable to such results. Vascular endothelial cells existed abundantly in the necrotic areas, and sinusoidal endothelial cells appeared following disappearance of the necrotic areas. VEGF mRNA expression in hepatocytes isolated from 70% resected liver was increased at 12 h after the operation and became marked between 72 and 168 h. Similar increase of hepatic VEGF expression was immunohistochemically seen. In conclusion, VEGF derives from nonparenchymal as well as parenchymal cells in rat liver after necrosis. The former might contribute to vascular endothelial cell proliferation and the latter to sinusoidal endothelial cell regeneration.     

Bioassay monitoring of waste PCB samples during chemical destruction treatments.

Capacitor oil samples (PCBs > 90%wt) were treated in a bench scale experiment to investigate the destruction of PCBs during chemical destruction processes (a catalytic hydrodechlorination treatment with palladium carbon and additional treatment with potassium tert-butyloxide). Using those results, this study confirmed the decrease of PCBs and other undesirable dioxin-like compounds such as PCDD/Fs in treated samples during the treatment. Dioxin-responsive chemical-activated luciferase expression (DR CALUX) AhR reporter gene bioassay was used to evaluate dioxin-like activity in the samples. During the treatment, the efficiency for PCB capacitor oil was around 99.99% or more in WHO-TEQ and CALUX-TEQ, whereas the sum of PCBs was reduced at a resulting efficiency of >99.9999%. In this study, a new cleanup procedure for separating PCBs from the mineral oil matrix was also developed for DR CALUX. The procedure consists of dimethylsulphoxide partitioning followed by silica gel-44% sulphuric acid reflux treatment and activated carbon chromatography. With the cleanup, CALUX-TEQ values were in good agreement with WHO-TEQ values and were as much as 3.3 times higher than WHO-TEQs for untreated/treated PCB-containing insulating oil samples. The DR CALUX results of mineral oil samples containing various PCB concentrations of 0.5-50 mg/kg (corresponding WHO-TEQs: 0.012-1.2 microg-TEQ/g) also correlated well with WHO-TEQs (CALUX-TEQ/WHO-TEQ ratio = 1.0-3.0), which was consistent with the theoretical quantification limit of the CALUX. These results supported the validity of the proposed clean-up method.     

Spectral analysis of subband adaptive digital filters

Subband adaptive digital filters at stationary points are analyzed in the frequency domain. Approximate expressions for the optimal subband filters are presented, and then, a spectral representation of the error variance is derived. These are expressed in the frequency domain and, hence, enable us to see the aliasing effects in subband adaptive filtering