Recovery of deuterium from H–D gas mixture by thermal diffusion in the Frazier scheme

The separation equation for predicting the deuterium recovery from H–D gas mixture by thermal diffusion in the cocurrent-flow Frazier schemes has been derived. The degrees of separation, as well as separation factors, for deuterium recovery in the Frazier scheme of cryogenic wall thermal-diffusion columns were estimated, with the use of the experimental data obtained by Arita et al. and the transport coefficients correlated in the previous work. Considerable enhancement in deuterium recovery is achievable if the number of thermal diffusion columns in a Frazier scheme is continuously increased, especially for the operation under higher volume flow rate and/or lower operating pressure.     

PAACP: A portable privacy-preserving authentication and access control protocol in vehicular ad hoc networks

Recently, several studies addressed security and privacy issues in vehicular ad hoc networks (VANETs). Most of them focused on safety applications. As VANETs will be available widely, it is anticipated that Internet services could be accessed through VANETs in the near future. Thus, non-safety applications for VANETs would rise in popularity. This paper proposes a novel portable privacy-preserving authentication and access control protocol, named PAACP, for non-safety applications in VANETs. In addition to the essential support of authentication, key establishment, and privacy preservation, PAACP is developed to provide sophisticated differentiated service access control, which will facilitate the deployment of a variety of non-safety applications. Besides, the portability feature of PAACP can eliminate the backend communications with service providers. Therefore, better performance and scalability can be achieved in PAACP.     

Influence of La substitution on the electrical properties of metal-ferroelectric (BiFeO3)-insulator (CeO2)-semiconductor nonvolatile memory structures

Metal-multiferroic (La-substituted BiFeO₃)-insulator (CeO₂)-semiconductor (MFIS) capacitors has been fabricated. The crystalline phase and amount of La³⁺ substitution at Bi-site were investigated by XRD and XPS in the postannealing temperature range from 500 to 700 °C, respectively. The microstructure and interfacial layer between CeO₂ and Si substrate were characterized by HRTEM. The memory windows as functions of insulator film thickness and DC power for La were measured. The maximum memory window is about 1.9 V under ±6 V applied voltage. The ferroelectric polarization increases with increasing substitution amount. The morphologies of La-substituted BiFeO₃ films were also studied by AFM.     

Influence of heating atmosphere on the properties of stannous phosphate glass

A low-viscosity 60 SnO–40 P₂O₅ (mol%) glass was reheated at 280 °C (about 45 °C above the glass-transition temperature) for 20 min in various atmospheres (Ar, air, and O₂), then the structure- and surface-related properties were examined. It was found that increase in \textP_{\textO 2} {\text{P}}_{{{\text{O}}_{ 2} }} increases surface hardness, reduces optical transmittance, and improves chemical durability. The above phenomena are explained in terms of the increased oxidation tendency of Sn²⁺ to Sn⁴⁺ on the glass surface during reheating in increased \textP_{\textO 2} {\text{P}}_{{{\text{O}}_{ 2} }} .     

Spectral tomography of concrete structures based on impact echo depth spectra

This paper proposes a spectral tomography for nondestructive test of concrete structures based on the spectral data of impact echo test. Firstly, a mesh is drawn on the surface of the concrete. Then, impact echo tests are performed at the grids. The recorded signals are processed to obtain the spectra of the concrete. The spectra are further transformed into the depth spectra and assembled into 3D volume data. Finally, spectral tomography is applied to the volume data to construct the image of the concrete structure for arbitrary cross-sections. Both numerical and experimental tests are performed to verify the effectiveness and reliability of the proposed imaging method. It is seen that the spectral tomography can be used to show the internal cracks in the concrete specimens successfully.     

New fabrication method for micro-pyramidal vertical probe array for probe cards

This paper presents a novel, precision process for fabricating a micro metal vertical probe array with various tip angles. The fabrication process includes an inclined and multiple-exposure in ultraviolet (UV) lithographic and Ni electroforming technology. Because of the light passing through an optical transparent homogenous material, the materials’ refractive index results in light path deflection. By changing the photomask and workpiece inclination, controllable various tip angles can be fabricated. The experimental results showed that micro metal vertical probes with 54°, 60° and 68° tip angles are achieved. The micro-pyramidal vertical probe array can be used in vertical-type probe cards without the conventional complicated assembly.     

Morphology,mechanical, and rheological behavior of microcellular injection molded EVA–clay nanocomposites

Ethylene vinyl acetate (EVA)/montmorillonite (MMT) nanocomposites diluted from master batch (50 wt.%) with EVA and EVAgMA was used in this study. The organoclay EVA nanocomposites were then injection molded by conventional and microcellular methods. Nitrogen was used as the blowing agent. The effect of organoclay content and MA grafted EVA on the morphology and the mechanical and rheological properties of the EVA–clay nanocomposites were then investigated. The results showed that the mechanical properties (tensile and impact) increased as the clay content increased. Cell size decreased as the clay loading increased. The EVAgMA nanocomposites had better mechanical properties than the EVA nanocomposites. XRD results showed that the EVAgMA nanocomposites have an exfoliated layered structure while the EVA nanocomposites are intercalated. Rheological results showed the viscosity is clay loading dependent and that the shear thinning effect occurs at high shear rates.     

Estimation of deuterium recovery from the separation of water isotopes in thermal-diffusion columns of a countercurrent-flow frazier scheme with optimal plate aspect ratio

The effect of plate aspect ratio on the performance of deuterium recovery from the separation of water–isotope mixture in thermal-diffusion columns of a countercurrent-flow Frazier scheme was investigated. The equations for the optimal plate aspect ratios and the corresponding maximum recovery and maximum production rate were derived. Considerable improvement in performance is obtained when thermal-diffusion columns are operated at the optimal plate aspect ratio. Further improvement can be achieved if the scheme is connected and operated in countercurrent flow, instead of concurrent flow.     

Using 10 Gb/s remodulation DPSK signal in self-restored colorless WDM-PON system

In this investigation, we propose and experimentally demonstrate the remodulation technique using DPSK format in both downlink and uplink traffics with high extinction ratio (ER) in colorless WDM-PON; together with a simple self-restored architecture against fiber fault. Error free operation was achieved in a 20-km-reach 10-Gb/s WDM-PON without dispersion compensation. Comparison with other wavelength remodulation schemes for WDM-PONs is also performed, showing the proposed scheme can be a potential candidate for next generation wavelength reuse WDM-PONs. In addition, the performance of self-protection has also been discussed and analyzed.