A New 1/4 Rate Modulation Techniques for Enhanced-xVSB System

In this paper, we describe a new 1/4 rate robust modulation techniques for Enhanced-xVSB system which is fully backward compatible with ATSC 8-VSB standard. 1/4 rate mode Enhanced-xVSB system provides broadcasters with a wide choice of trade-offs of data rate vs amount of robustness of enhanced data for pedestrian/mobile services. Lab test results of proposed Enhanced-xVSB 1/4 rate mode robust stream is a significantly improved multipath as well as AWGN reception performance for Enhanced-xVSB receiver. We suggest an Enhanced-xVSB terrestrial broadcasting system for ATSC HDTV and pedestrian/portable TV simultaneous broadcasting service providing     

Room-temperature ferromagnetism in Cu doped GaN nanowires

We report magnetism in Cu doped single-crystalline GaN nanowires. The typical diameter and the length of the Ga1-xCuxN nanowires (x = 0.01, 0.024) are 10-100 nm and tens of micrometers, respectively. The saturation magnetic moments are measured to be higher than 0.86 microB/Cu at 300 K, and the Curie temperatures are far above room temperature. Anomalous X-ray scattering and X-ray diffraction measurement make it clear that Cu atoms substitute the Ga sites, and they largely take part in the wurtzite network of host GaN. X-ray absorption and X-ray magnetic circular dichroism spectra at Cu L(2,3) edges show that doped Cu has local magnetic moment and the electronic configuration of it is mainly 3d9 but mixed with a small portion of trivalent component. It seems that the ionocovalent bonding nature of Cu 3d orbital with surrounding semiconductor medium makes Cu atom a mixed electron configuration and local magnetic moments. These outcomes suggest that the Ga1-xCuxN system is a room-temperature ferromagnetic semiconductor.     

Spatial control of quantum sized nanocrystal arrays onto silicon wafers

Monolayer arrays of monodispersed nanocrystals (<10 nm) onto three dimensional (3D) substrates have considerable potential for various engineering applications such as highly integrated memory devices, solar cells, biosensors and photo and electro luminescent displays because of their highly integrated features with nanocrystal homogeneity. However, most reports on nanocrystal arrays have focused on two dimensional (2D) flat substrates, and the production of wafer-scale monolayer arrays is still challenging. Here we address the feasibility of arraying nanocrystal monolayers in wafer-scale onto 3D substrates. We present both metal (Pd) and semiconductor (CdSe) nanocrystals arrayed in monolayer onto trenched silicon wafers (4 inch diameter) using a facile electrostatic adsorption scheme. In particular, CdSe nanocrystal arrays in the trench well showed superior luminescent efficiency compared to those onto the protruded trench flat, due to the densely arrayed CdSe nanocrystals in the vertical direction. Furthermore, the surface coverage controllability was investigated using a 2D silicon substrate. Our approach can be applied to generate highly efficient displays, memory chips and integrated sensing devices.     

Effects of thermal annealing in oxygen plasma for buffer layers on properties of ZnO thin films

ZnO thin films with ZnO buffer layers were grown by plasma-assisted molecular beam epitaxy (PA-MBE) on p-type Si(100) substrates. Before the growth of the ZnO thin films, the ZnO buffer layers were deposited on the Si substrates for 20 minutes and then annealed at the different substrate temperature ranging from 600 to 800 degrees C in oxygen plasma. The structural and optical properties of the ZnO thin films have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and room-temperature (RT) photoluminescence (PL). A narrower full width at half maximum (FWHM) of the XRD spectra for ZnO(002) and a larger grain are observed in the samples with the thermal annealed buffer layers in oxygen plasma, compared to those of the as-grown sample. The surface morphology of the samples is changed from rugged to flat surface. In the PL spectra, near-band edge emission (NBEE) at 3.2 eV (380 nm) and deep-level emission (DLE) around 1.77 to 2.75 eV (700 to 450 nm) are observed. By increasing the annealing temperatures up to 800 degrees C, the PL intensity of the NBEE peak is higher than that of the as-grown sample. These results imply that the structural and optical properties of ZnO thin films are improved by the annealing process.     

Preparation and antioxidative activity of hoki frame protein hydrolysate using ultrafiltration membranes

Hoki frame protein, which is normally discarded as an industrial by-product in fish plants, was hydrolyzed with various enzymes. The antioxidative activity of the hydrolysates was investigated, and the results showed that pepsin hydrolysate has the highest activity. Hoki frame protein hydrolysates (HPH) prepared by pepsin were fractionated according to the molecular mass into four major types, HPH I (5–10 kDa), HPH II (3–5 kDa), HPH III (1–3 kDa), and HPH IV (below 1 kDa), using an ultrafiltration membrane. HPH III showed a higher antioxidative activity than the other hydrolysates in a linoleic acid emulsion system. In addition, the free-radical scavenging activities of the fractionated hydroysates were evaluated using electron spin resonance spectroscopy. The results showed that HPH III has the highest scavenging effects for 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, alkyl and superoxide anion radicals, and the inhibition pattern was dose-dependent.     

Hierarchical organization of Au nanoparticles in a poly(vinyl carbazole) matrix for hybrid electronic devices

We report a novel one-step method for the preparation of hierarchically patterned Au nanoparticles in a conducting polymer matrix by controlling the interface properties between Au nanoparticles and the conducting polymer matrix. The terminal group of capping molecules for the Au nanoparticles was modified to change the interface properties, not to change the size of the Au nanoparticles which affects their intrinsic properties. By modulating the interface properties, it is possible to construct Au nanoparticle-conducting polymer composites with two different structures: one presents a triple layer in which the conducting polymer layer is sandwiched between Au nanoparticle layers at the top and bottom; the other exhibits a form like a raisin cake in which Au nanoparticles are homogeneously organized in the conducting polymer matrix. High-resolution transmission electron microscopy was used to study the morphology and patterning of Au?nanoparticles in the conducting polymer matrix.