Search

A novel optical encryption method is proposed in this paper to achieve 3-D image encryption. This proposed encryption algorithm combines the use of computational integral imaging (CII) and linear-complemented maximum-length cellular automata (LC-MLCA) to encrypt a 3D image. In the encryption process, the 2-D elemental image array (EIA) recorded by light rays of the 3-D image are mapped inversely through the lenslet array according the ray tracing theory. Next, the 2-D EIA is encrypted by LC-MLCA algorithm. When decrypting the encrypted image, the 2-D EIA is recovered by the LC-MLCA. Using the computational integral imaging reconstruction (CIIR) technique and a 3-D object is subsequently reconstructed on the output plane from the 2-D recovered EIA. Because the 2-D EIA is composed of a number of elemental images having their own perspectives of a 3-D image, even if the encrypted image is seriously harmed, the 3-D image can be successfully reconstructed only with partial data. To verify the usefulness of the proposed algorithm, we perform computational experiments and present the experimental results for various attacks. The experiments demonstrate that the proposed encryption method is valid and exhibits strong robustness and security.

Bond coatings, CoNiCrAlY, are prepared on Inconel 738 substrate by vacuum plasma spray (VPS). Mechanical properties of VPSed CoNiCrAlY coatings are investigated via Taguchi method and L18(21×37)[removed info]orthogonal arrays to determine the optimal setting and the relationship of experimental variables. Seven parameters were considered as follows: (A) arc current; (B) primary gas flow rate; (C) secondary gas flow rate; (D) stand-off distance; (E) working pressure; (F) carrier gas flow rate (Ar); and (G) powder feeding rate.[removed info]The effect of carrier gas flow rate on the porosity is determined to be the highest among the parameters investigated. Higher microhardness values are observed for the VPSed coatings as compared to the coatings prepared by conventional high velocity oxygen fuel probably due to low amount of the porosity.

Microstructural features, mechanical properties, and corrosion properties of a SAF2205 duplex stainless steel (DSS) were systematically investigated as functions of cooling rate during casting and heat treatment conditions. The choice of a duplex stainless steel was a SAF2205 alloy, of which composition is 0.03C, 21~23Cr, 4.5~6.5Ni, 2.5~3.5Mo, 0.08~0.2N, 1.0Si, and 2.0Mn with remaining Fe. A 5-stepped sand mold and the permanent Y-block mold were used to check the effect of cooling rate during solidification. The microstructural characteristics, such as grain size, the d/γ ratio, the existence of the carbides and σ phase has been noticed to greatly change with the variation of cooling rate during the casting procedure. Various heat treatment conditions were also examined to achieve the optimized mechanical properties of DSS. Based on the preliminary examination, the feasibility study of utilization of centrifugal casting has been carried out for the production of better quality DSS pipe components. Melting and casting practices of DSS during centrifugal casting in an air atmosphere were systematically investigated in order to obtain the optimized process parameters.

Endurable water-repellent coated layers have been formed on safety glasses for automobiles via a sol-gel based spray coating process. Coated films are composed of a silica underlayer (∼800Å) and a fluorocarbon layer in which the formed silica shows a definite surface roughness and acts as the enhancement factor for chemical and mechanical durability. Durability is a function of the degree of surface roughness, structural fineness and homogeneity. Dual stage aging in silica sol controls a wide range of surface roughness. Water-repellency is degraded gradually by a combination of sunlight (ultraviolet), water, and abrasion. Spray coating on large size and curved safety glasses was successfully carried out.

Ferroelectric Pb(Zr,Ti)O3thin films were successfully fabricated on Pt-coated Si substrates by the electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR PECVD) method using metal-organic (MO) sources. Perovskite structures with well-developed crystalline grains are obtained at a substrate temperature of 500 °C. These PZT films, with thicknesses of about 1000Å, show high charge storage densities (Pmax− Pr= 10–15 μC cm−2for 1.5 V operation) and low leakage current densities (≈ 10−6A cm−2at 1.5 V). The effects of the Zr/Ti concentration ratio in the film and the rapid thermal annealing on the electrical properties of the films were also studied.

We report a novel solution-processible polymer, poly(2-dimethyloctylsilyl-1,4-phenylenevinylene) (DMOS-PPV) which shows a very high photoluminescence efficiency (60% for thin solid films). With the use of aluminium as cathode, an internal quantum efficiency as high as 2% has been obtained from bilayer diodes. The photoluminescence excitation measurement on a pristine film suggests constant efficiency for singlet intrachain exciton generation.

We report a novel solution-processible polymer, poly(2-dimethyloctylsilyl-1,4-phenylenevinylene(DMOS-PPV) which shows a very high photoluminescence efficiency (60% for thin solid films). With the use of aluminium as cathode, an internal quantum efficiency as high as 2% has been obtained from bilayer diodes. The photoluminescence excitation measurement on a pristine film suggests constant efficiency for singlet intrachain exciton generation.