The Fe-22wt.%Cr-6wt.%Al foams were fabricated via the powder alloying process in this study. The structural characteristics, microstructure, and mechanical properties of Fe-Cr-Al foams with different average pore sizes were investigated. Result of the structural analysis shows that the average pore sizes were measured as 474 μm (450 foam) and 1220 μm (1200 foam). Regardless of the pore size, Fe-Cr-Al foams had a Weaire-Phelan bubble structure, and α-ferrite was the major constituent phase. Tensile and compressive tests were conducted with an initial strain rate of 10−3 /s. Tensile yield strengths were 3.4 MPa (450 foam) and 1.4 MPa (1200 foam). Note that the total elongation of 1200 foam was higher than that of 450 foam. Furthermore, their compressive yield strengths were 2.5 MPa (450 foam) and 1.1 MPa (1200 foam), respectively. Different compressive deformation behaviors according to the pore sizes of the Fe-Cr-Al foams were characterized: strain hardening for the 450 foam and constant flow stress after a slight stress drop for the 1200 foam. The effect of structural characteristics on the mechanical properties was also discussed.

GaN is most commonly used to make LED elements. But, due to differences of the thermal expansion coefficient and lattice mismatch with sapphire, dislocations have occurred at about 109~1010/cm2. Generally, a low temperature GaN buffer layer is used between the GaN layer and the sapphire substrate in order to reduce the dislocation density and improve the characteristics of the thin film, and thus to increase the efficiency of the LED. Further, patterned sapphire substrate (PSS) are applied to improve the light extraction efficiency. In this experiment, using an AlN buffer layer on PSS in place of the GaN buffer layer that is used mainly to improve the properties of the GaN film, light extraction efficiency and overall properties of the thin film are improved at the same time. The AlN buffer layer was deposited by using a sputter and the AlN buffer layer thickness was determined to be 25 nm through XRD analysis after growing the GaN film at 1070˚C on the AlN buffer CPSS (C-plane Patterned Sapphire Substrate, AlN buffer 25 nm, 100 nm, 200 nm, 300 nm). The GaN film layer formed by applying a 2 step epitaxial lateral overgrowth (ELOG) process, and by changing temperatures (1020~1070˚C) and pressures (85~300 Torr). To confirm the surface morphology, we used SEM, AFM, and optical microscopy. To analyze the properties (dislocation density and crystallinity) of a thin film, we used HR-XRD and Cathodoluminescence.

A zinc oxide (ZnO) hybrid structure was successfully fabricated on a glass substrate by metal organic chemical vapor deposition (MOCVD). In-situ growth of a multi-dimensional ZnO hybrid structure was achieved by adjusting the growth temperature to determine the morphologies of either film or nanorods without any catalysts such as Au, Cu, Co, or Sn. The ZnO hybrid structure was composed of one-dimensional (1D) nanorods grown continuously on the two-dimensional (2D) ZnO film. The ZnO film of 2D mode was grown at a relatively low temperature, whereas the ZnO nanorods of 1D mode were grown at a higher temperature. The change of the morphologies of these materials led to improvements of the electrical and optical properties. The ZnO hybrid structure was characterized using various analytical tools. Scanning electron microscopy (SEM) was used to determine the surface morphology of the nanorods, which had grown well on the thin film. The structural characteristics of the polycrystalline ZnO hybrid grown on amorphous glass substrate were investigated by X-ray diffraction (XRD). Hall-effect measurement and a four-point probe were used to characterize the electrical properties. The hybrid structure was shown to be very effective at improving the electrical and the optical properties, decreasing the sheet resistance and the reflectance, and increasing the transmittance via refractive index (RI) engineering. The ZnO hybrid structure grown by MOCVD is very promising for opto-electronic devices as Photoconductive UV Detectors, anti-reflection coatings (ARC), and transparent conductive oxides (TCO).

We describe the preparation of superparamagnetic nanoclusters (SNCs) by fine-tuning of the seed Fe3O4 nanoparticle sizes to enhance and their T2 relaxivity can be increased by > 4-fold. Therefore, with 11 nm seed core and PVA coating, SNC-11 exhibit a higher T2 relaxivity than other cluster condition. So fabricating the cluster, seed size is the most important influence the T2 relaxivity. As well as, in vitro cellular imaging results demonstrated the strong potential of SNCs for clinical applications by targeting affinity. According to the experiments, with 11 nm seed core and PVA coating, SNC-11 exhibited the highest T2 relaxivity of 454 mM-1s-1 due to the strong seed size effect on their magnetic sensitivity, indicating superior magnetic resonance (MR) contrast efficiency. Further in vitro cellular imaging results demonstrated the strong potential of SNCs for clinical applications.

Because shore(ship) to ship(shore) communication service via INMARSAT pay expensive cost, satellite service typically use two stage service that land users dial up LES(Land Earth Station) for sending or receiving message. In order to send and receive message, land users must maintain online state with LES on dedicated line. Also, two stage INMARSAT communication service must consume long time that processes step by step. In case of large company, they have own communication system, but small companys communicate simple messages with only telex. This paper describes the design and implementation of an integrated communication services via INMARSAT-C. This system uses inexpensive INMARSAT-C for transmission between ship and land. Because this system provides web and E-Mail interface, users send and receive messages easily and quickly. This system provides most users with inexpensive and easy communication facilities between ship and land.