Visual Cryptography Based on an Interferometric Encryption Technique

This paper presents a new method for a visual cryptography scheme that uses phase masks and an interferometer. To encrypt a binary image, we divided it into an arbitrary number of slides and encrypted them using an XOR process with a random key or keys. The phase mask for each encrypted image was fabricated under the proposed phase‐assignment rule. For decryption, phase masks were placed on any path of the Mach‐Zehnder interferometer. Through optical experiments, we confirmed that a secret binary image that was sliced could be recovered by the proposed method.     

Enhancement of Mechanical Properties of Extruded Mg–9Al–1Zn–1MM–0.7CaO–0.3Mn Alloy Through Pre-aging Treatment

The effect of pre-aging treatment before extrusion has been investigated in Mg–9.0Al–1.0Zn–1MM–0.7CaO–0.3Mn alloy. The as-cast microstructure consists of α-Mg dendrite with secondary solidification phase particles, (Mg, Al)₂Ca, β-Mg₁₇Al₁₂ and Al₁₁RE₃ at the inter-dendritic region. After extrusion, β-Mg₁₇Al₁₂ precipitates are present, but higher density and more homogeneous distribution in pre-aged alloy. In addition, μm-scale banded bulk β-Mg₁₇Al₁₂ particles are generated during extrusion. Al₁₁RE₃ particles are broken into small particles, and are aligned along the extrusion direction. (Mg, Al)₂Ca particles are only slightly elongated along the extrusion direction, providing stronger particle stimulated nucleation (PSN) effect by severe deformation during extrusion. The mechanical properties can be significantly enhanced by introducing pre-aging treatment, i.e. β-Mg₁₇Al₁₂ precipitates provide grain refining and strengthening effects and (Mg, Al)₂Ca particles provide PSN effect.     

Efficient attack strategy for legitimate energy-powered eavesdropping in tactical cognitive radio networks

Wireless Networks - The cognitive radio network (CRN) is not only considered a useful medium for users, but it is also an environment vulnerable to proactive attackers. This paper studies an attack...     

The protective effects of Gastrodia elata Blume extracts on middle cerebral artery occlusion in rats

Food Science and Biotechnology - To investigate the effects of Gastrodia elata Blume (GEB) and 4-hydroxybenzyl alcohol (HBA) on brain damage, GEB or HBA was administered orally for 14 days...     

Identification of estrone in pomegranate (Punica granatum) extracts by liquid chromatography-tandem mass spectrometry

There were some reports that the pomegranate juice, seeds, and peel extracts contain steroid hormones including estrone, but the results were controversial. This study was performed to identify estrone in pomegranate extracts through a more sensitive and validated technology. Separation and determination of estrone was carried out using high performance liquid chromatography (HPLC) system with triple quadrupole mass spectrometry. Low concentration of estrone (4.5±0.38 ng/mL) was detected in pomegranate extracts with adequate precision value. The amount of estrone in pomegranate extracts was calculated as 16.4, 18.2, and 20.2 ng/mL, respectively, adjusted by extraction efficiency (average 25.6%) in the precision verification.     

Uncertainty assessment of streamflow projection under the impact of climate change in the Lower Mekong Basin: a case study of the Srepok River Basin,Vietnam

Uncertainty assessment of future projection of streamflow is of the essence for an effective formulation of water resources management and planning adaptive to climate change. The aim of this study is to investigate the uncertainty in streamflow projection under the climate change impact in the Srepok River Basin. Uncertainty associated with emission scenarios (RCP2.6, RCP4.5 and RCP8.5), General Circulation Models (GCMs) (CanESM2, CNMR‐CM5 and HadGEM2‐AO), statistical downscaling methods (delta change method, quantile mapping and SDSM), and hydrological models (ANN, HEC‐HMS and SWAT) is examined. The results showed the largest uncertainty source of the streamflow projection is the GCM simulations, followed by the statistical downscaling methods, hydrological models and emission scenarios. In addition, the use of hydrological models has a considerable impact on uncertainty in the simulations of dry seasonal streamflow. Generally, the present study highlighted the importance of using multi‐GCMs in the studies on hydrological impact of climate change.     

Stability of high temperature chemical vapor deposited silicon based structures on metals for solar conversion

Highly crystallized silicon layers were grown on metal sheets at high temperature (950 degrees C) by thermal CVD from silane. An intermediate buffer layer was mandatory to prevent interdiffusion and silicide formation but also to compensate lattice parameters and thermal expansion coefficients mismatches between metal and silicon and ideally transfer some crystalline properties (grain size, texture) from the substrate to the silicon layer. After a thermodynamic study, aluminum nitride or titanium nitride diffusion barrier layers were selected and processed by CVD. The structure and the interfaces stabilities of these silicon/nitride/metal stacks were studied by field effect gun scanning and transmission electron microscopy, X-ray diffraction, Raman and energy dispersive X-ray spectroscopy. As a result, TiN deposited by CVD appears to be an efficient material as a buffer layer between steel and silicon.     

Double corrosion protection mechanism of molybdate-doped polypyrrole/montmorillonite nanocomposites

Nanocomposites based on polypyrrole (PPy) doped with molybdate (PPy(MoO₄)) and montmorillonite (MMT) were prepared by chemical polymerisation. The morphology of nanocomposite particles was studied by scanning electron microscopy. The chemical structure of conducting polymers (CPs) in nanocomposites was characterised by Raman spectroscopy. The thermal analysis showed that all CPs in the nanocomposites were stable for more than 500°C. Energy diffraction X-ray showed that the amount of Mo in element the PPy(MoO₄)/MMT nanocomposite was 5.55%. The corrosion protection mechanism of the nanocomposites was investigated by electrochemical methods, showing that MMT acted as a barrier layer in nanocomposite and molybdate as an inhibitor for corrosion protection of metal.     

Wavelength re-generation and re-modulation using optical phase lock loop techniques for 100-Gb/s DQPSK up-stream transmission in DWDM passive optical networks

We demonstrate, by partial experiment and simulation, a re-modulation scheme of the lightwave carrier imbedded in a downstream optical signals under differential quadrature phase shift keying (DQPSK) modulation format for upstream transmission over passive optical networks (PONs) at a bit rate of 100 Gb/s. The recovery of the optical carrier with the precise wavelength is implemented using an injection laser incorporating an optical phase locked loop (OPLL). In the computer simulation, the OPLL is implemented by a Simulink model consisting of interconnected system blocks following exactly the physical phenomena of the hardware structures. This model is then integrated with DQPSK modulation formats for up- and down-transmissions in PONs. Pulse shaping of Non-Return-to-Zero and Return-to-Zero (RZ) of 50% duty cycle and 67% duty cycle are used, respectively. Dispersion tolerance of 25 ps/nm with a bit error rate (BER) of 10⁻⁹ is achieved for both down- and upstream transmissions over fully dispersion compensated 80- km standard SMF and 1.5- km SSMF equivalent dispersion with carrier suppressed RZ pulse shaping (CS-RZ 67%). The contribution to BER by the timing synchronization error at the sampling of the optical network unit for re-modulation and related power penalty of these modulation formats is also investigated. It is noted that using the optical phase locking technique it is possible to remove any cross talks which may be generated from nonlinear effects such as cross-phase modulation, self-phase modulation, and four wave mixing.