Suppression of Li deposition on surface of graphite using carbon coating by thermal vapor deposition process

10 wt.% carbon-coated natural graphite (NC-10) is prepared by thermal vapor deposition. The carbon coating is electrochemically investigated at −5 °C; it improves lithium intercalation in the graphite's interlayer spacing. NC-10 graphite clearly shows 3 voltage plateaus and a higher capacity during the first charge/discharge cycle at −5 °C than uncoated natural graphite. XRD study of the electrode after the first charging shows increased lithium intercalation into the graphite layers and also suppression of lithium deposition on the graphite's surface. Due to the homogeneous potential profile on the graphite surface, carbon coating enhance lithium intercalation at −5 °C. In addition, NC-10 shows less lithium deposition on the surface than bare natural graphite.     

Ultrafine electrospun nanofiber created from cross-linked polyimide solution

This paper reports a novel study focused on the preparation of non-beaded ultrafine uniform nanofibers with a narrow fiber diameter distribution from fluorinated polyimide by electrospinning. Increasing the viscosity of the polymer solutions by the addition of hexamethylenediamine (HMDA) as a cross-linking agent can result in electrospun nanofibers with a smaller diameter. The cross-linking reaction between the polyimide and HMDA was examined by FTIR-ATR and GPC under different cross-linking times. The ultrafine uniform nanofibers were achieved with the use of HMDA. Finally, we successfully prepared the non-beaded ultrafine uniform nanofibers within a narrow nano-range (27 ± 5 nm).     

Review of Topographic and Soil Conditions for Liquefaction-Related Damage Induced by the 2007 Off Mid-Niigata Earthquake

The 2007 Niigata-ken Chuetsu-oki (Off Mid-Niigata) earthquake caused the liquefaction of the sandy soil distributed near the coast of the Japan Sea in the middle of Niigata Prefecture. The liquefaction-induced damage occurring in many residential areas was investigated in detail by means of victim interviews, visual inspections, Swedish Weight Sounding tests, Standard Penetration Tests, old topographical map examinations, etc. Based on in situ soil investigations, the liquefied soil layers were estimated for each area. As a result, it was confirmed that the liquefied areas were mainly sand dune hinterlands, flood plains, reclaimed old river channels and sandy fills with high groundwater table. Among them, damage was especially serious on land having an inclined ground surface due to the flow of foundations, on the cut-fill borders of artificially developed land due to landslides and at the toes of sand dune slopes due to the thrust of the sliding soil and/or the collision of the sliding soil with objects. These investigation results also revealed that soil improvement by cement mixed columns is an effective countermeasure against liquefaction-induced damage unless lateral spreading of the subsoil arises.     

Novel polyimide-based electrospun carbon nanofibers prepared using ion-beam irradiation

This paper describes a novel study focused on preparing carbon nanofibers, with a narrow fiber diameter distribution, from a fluorinated polyimide using both electrospinning and ion-beam irradiation. We specifically focused on the effects of ion species and ion fluences on the electrical conductivity of the nanofiber. The nanofibers were successfully prepared in the diameter range from 340 nm to 1500 nm by varying the concentration of polyimide solution using electrospinning. The Raman spectrum of the ion-irradiated nanofiber included the two well-known D (1360 cm^?1) and G (1580 cm^?1) peaks, indicating that the nanofiber surface changed to a carbon-enriched material. The carbon nanofibers underwent a more ordered graphitic carbon structure with an increase in the ion fluence and the electrical conductivity of the nanofiber irradiated at 1 × 10¹⁶ ions/cm² of Ar⁺ was 0.18 S/cm. In addition, the electrical conductivities of the ion-irradiated nanofibers increased in the order, He⁺ < Ne⁺ < Ar⁺, which indicated that the amount of nuclear energy in the ion species had the most influence on the electrical conductivity. However, the higher electrical conductivity of the carbon nanofibers is required to realize their industrial applications. This paper is the first to address the properties of the electrical conductivity of the carbon nanfibers prepared by electrospinning and ion irradiation as a new approach.     

Calcium borate flame retardation system for epoxy molding compounds

A new flame retardation system for epoxy molding compounds was investigated for application to semiconductor packaging. By adding a small volume of calcium borate as a flame retardant, the flammability of the epoxy molding compound decreased. The flammability was not decreased proportionally with the volume of calcium borate. To further enhance flammability, an excess amount of phenolic resin was added to the epoxy molding compound. With the effects of calcium oxide and the excess phenolic resin, we developed an epoxy molding compound which has a flame‐retardant level sufficient to satisfy the V‐0 classification of the UL94 rating. We also found that calcium oxide in the calcium borate accelerates the curing reaction of epoxy compounds due to its absorption of water from the phenolic resin hardener. Calcium hydroxide formed from calcium oxide and water was also considered to contribute to the decrease in flammability by releasing water at high temperatures. The flame retardation mechanism of this developed epoxy compound is also discussed. Finally, the developed epoxy compound was proved to have suitable moldability, mechanical properties, and durability for use as semiconductor packaging. POLYM. ENG. SCI., 46:799–806, 2006. © 2006 Society of Plastics Engineers     

Correlation analysis for forced vibration test of the Haulien large scale seismic test program

The correlation analysis for forced vibration test of a 1/4 scale containment SSI test model constructed in Hualien, Taiwan, was carried out for the case of backfilled foundation. Prior to the correlation analysis, structural property was revised so that calculated fundamental frequency of fixed base condition was adjusted to that derived from test results. Correlation analysis was carried out by ‘Lattice Model’ which was able to estimate soil-structure interaction effects with embedment. The analysis results coincide well with test results and concluded that the mathematical soil-structure interaction model established by the correlation analysis is efficient to estimate a dynamic soil-structure interaction effect with embedment. This mathematical model will be applied as a basic model of simulation analysis for earthquake observation records.     

(211)-Oriented Domain Formation During Growth of ZnTe on m-Plane Sapphire by MBE

ZnTe epilayers have been grown on 2°-tilted m-plane $\left( {10\overline{1} 0} \right)$ sapphire substrates by molecular beam epitaxy. Pole figure imaging was used to study the domain distribution within the layer, and the pole figures of 111, 220, 004, and 422 ZnTe and $30\overline{3} 0$ sapphire were measured. Computer simulation was used to analyze the symmetry of the diffraction patterns seen in the pole figure images. Stereographic projections were also compared with the pole figures of 422 and 211 ZnTe, confirming that single-domain (211)-oriented ZnTe epilayers had been grown on the 2°-tilted m-plane sapphire substrates. Although differences in crystal structure and lattice mismatch were severe in these heterostructures, precise control of the substrate surface’s lattice arrangement would result in the formation of high-quality epitaxial layers.     

Synthesis of Ga2O3–Al2O3 Catalysts by a Coprecipitation Method for CH4-SCR of NO

Synthesis of the γ-Ga₂O₃–Al₂O₃ solid solutions by the coprecipitation method was examined. Precipitates were obtained by adding at once an aqueous solution of aluminum and gallium nitrates to an excess base solution (reverse strike precipitation). The precipitates were calcined at 700 °C to give γ-Ga₂O₃–Al₂O₃ solid solutions. When an ammonium carbonate solution was used as the precipitant, ammonium aluminum carbonate hydroxide (ammonium dawsonite, AACH)–ammonium gallium carbonate hydroxide (AGCH) solid solutions were obtained. Calcination of the AACH–AGCH solid solutions at 700 °C gave the γ-Ga₂O₃–Al₂O₃ solid solutions which exhibited high activity for selective catalytic reduction of NO with methane.