Wall slip and melt-fracture of polystyrene melts in capillary flow

We investigated slip and unstable flow phenomena of polystyrene melts in capillaries from the view of the effects of temperature and molecular weight by using three polystyrene samples with different molecular weights (M_w = 192,000, M_w = 258,000, and M_w = 321,000). The slip velocities are estimated by the Mooney method and the modified Mooney method. We found that the slip velocity increases and the critical slip stress above which a slip starts to occur decreases with the temperature. We also observed the melt-fracture at above a critical melt-fracture stress higher than . We found that the onset of melt fracture is affected by the extensional stress near the entry region to the capillary in the barrel and the melt-fracture tends to easily occur with increase of the molecular weight, but is not sensitive to the temperature.     

Influence of cathode polarization on the chromium deposition near the cathode/electrolyte interface of SOFC

Chromium poisoning phenomena were compared among three SOFC cathodes using (La_0.8Sr_0.2)_0.98MnO₃ (LSM), La_0.6Sr_0.4Fe_0.8Co_0.2O₃ (LSCF) and LaNi_0.6Fe_0.4O₃ (LNF) at 700 °C by changing cathode polarization (0–400 mV). Chromium vapor deposited near the electrolyte for LSM and LNF, and the amount of the deposition increased with increasing cathode polarization. In the case of LSCF, chromium deposited near the cathode surface under smaller cathode polarization (≤200 mV). Under larger cathode polarization (≥300 mV), however, chromium deposition near the cathode/electrolyte interface similarly increased for the three cathodes. Cathode polarization facilitated the chromium deposition and there seemed to be no correlation with the current density. Microscopic distribution of the deposited chromium, which was located on the surface of LSM, LSCF, LNF grains, and also on the surface of zirconia and ceria, seemed to correspond to the distribution of oxygen vacancy by cathode polarization at the electrode reaction sites. Chromium deposition on the zirconia surface seemed to be assisted by metal oxides segregated from the cathode material, which can conduct electron required for generating oxygen vacancy continuously. Oxygen deficiency on the surface of the deposited chromium was confirmed and interdiffusion of chromium and zirconium caused by cathode polarization was also suggested.     

A 500-MHz pipelined burst SRAM with improved SER immunity

This paper describes a 0.25-μm, 64 K×36 bit pipelined burst SRAM using a 6.156-μm² cell. It realizes over 500-MHz operation using a lower cost double metal process, Internal 16 K×144 organization by T-shaped bit line array reduces 20% of latency, 20% of active power, and 8.5% of die size. The low power also enables us to use lower cost thin quad flat type packages. Our solution to the soft error problem, a shallow triple well structure and four-transistor cell with stacked capacitor, improved soft error rate by 3.5 orders of magnitude compared with the conventional SRAM cell     

Two-tone metal pattern transfer technique using a single mold surface

There is growing demand for a fine metal-patterning technique to fabricate devices of the next generation, such as patterned media, plasmon photonics, and nanoscale electrodes. Nanotransfer printing (nTP) using a nanoscale patterned stamp has recently received considerable attention because of its high throughput and high resolution. To increase the throughput of the process further, it will be necessary to be able to use the stamp repeatedly, because fabrication of the stamp is a comparatively lengthy process. However, after the first transfer process, residual metal in the concave areas of the stamp obstructs the continuation of the transfer process. We examined a two-tone metal pattern transfer technique using a single mold after the first transfer process. The obstructive gold pattern in the mold could be removed and obtained as a negative tone by using a layer of polymer as a transfer substrate.     

Stability of free convection with uniform suction or injection from a vertical flat plate subjected to a constant wall heat flux

Summary A theoretical study is presented for the stability characteristics of the laminar free convection boundary layer flow along a vertical porous (permeable) flat plate subjected to a constant heat flux. The disturbance equations are solved numerically on the basis of the linear stability theory for a wide range of values of the modified Grashof number,G, and some values of the suction or injection parameterX when the Prandtl number, Pr, is 0.73 (air). These solutions indicate the important role of the parametersG andX on the flow and heat transfer characteristics. It is found that the present results are in very good agreement with those from the open literature.     

Preparation and biological evaluation of hydroxyapatite-coated nickel-free high-nitrogen stainless steel

Calcium phosphate was formed on nickel-free high-nitrogen stainless steel (HNS) by chemical solution deposition. The calcium phosphate deposition was enhanced by glutamic acid covalently immobilized on the surface of HNS with trisuccinimidyl citrate as a linker. X-ray diffraction patterns and Fourier transform infrared spectra showed that the material deposited on glutamic acid-immobilized HNS within 24 h was low-crystallinity calcium-deficient carbonate-containing hydroxyapatite (HAp). The biological activity of the resulting HAp-coated HNS was investigated by using a human osteoblast-like MG-63 cell culture. The HAp-coated HNS stimulated the alkaline-phosphate activity of the MG-63 culture after 7 days. Therefore, HAp-coated HNS is suitable for orthopedic devices and soft tissue adhesion materials.     

RAST: finding related documents based on triplet similarity

With the increasing amount of information available in recent years, searching for the desired content is becoming a challenging task. In this work, a tool for searching abstracts submitted to scientific conferences is introduced. It not only searches abstracts by the given keyword(s) but also displays abstracts related to a single or multiple selection. It also displays highly relevant abstracts together with possible keywords to help users refine their search. Analysis of the conditional similarity algorithm proposed here has shown that it does provide better output compared to ordinary cosine similarity, as well as the list of possible keywords reflects results of latent topic analysis. An interface for storing and sorting selected abstracts for future review and/or printing is also provided.     

Microstructure and analysis of oxide scales formed on Cr-Si-Ni compacts in air and H2O-containing atmosphere

The purpose of this study was to characterize the oxide scales formed on various Cr-Si-Ni compacts at 1273 K in air and H₂O-containing atmosphere by TEM. It was found that CrSi₂-(5-20)mass%Ni compacts form double layer scales, consisting of an outer Cr₂O₃ layer and an inner SiO₂ layer. The oxide scale changed from SiO₂- to Cr₂O₃-based scale with an increase in the Ni concentration. However, it was observed that the oxide scale formed in H₂O-containing atmospheres showed local SiO₂ growth into the substrate. This result suggests that the inward oxidant diffusion promotes the local growth of SiO₂ in the H₂O-containing atmospheres.