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This study grew nitrogen doped ultrananocrystalline diamond (N-UNCD) conductive layer on InGaN-based light emitting diodes (LEDs) using the concave nanopattern (CNP) enhanced nucleation. The low nucleation density of the N-UNCD on bare LEDs (Br-LED) resulted in an island morphology. The nucleation density of the N-UNCD increased significantly from 1.8 × 108 cm−2 for Br-LED to 3.6 × 109 cm−2 for LEDs with a CNP density of 6.1 × 109 cm−2 (CNP-LED). The N-UNCD preferred to nucleate inside the CNP during the initial growth stage. The N-UNCD islands then merged and grew laterally to form a continuous thin film within a thickness of 300 nm. The N-UNCD/CNP-LED exhibited a stable electroluminescence peak wavelength of ~447.1 nm in the injection current range of 10–100 mA. The decrease in the compressive stress due to removing the p-GaN layer (i.e. the CNP structure) resulted in a quantum confined Stark effect (QCSE) mitigation in the multi-quantum wells (MQWs). In addition, the lower turn on voltage caused a lower electric field in the MQWs and diminished the screen of the QCSE. The N-UNCD prepared by the proposed nucleation technique demonstrated a promising conductive layer for InGaN-based LEDs.

Aluminum oxide (Al 2 O 3 ) thin films were deposited on silicon (100) and quartz substrates by pulsed laser deposition (PLD) at an optimized oxygen partial pressure of 3.0×10 −3 mbar in the substrate temperatures range 300–973 K. The films were characterized by X-ray diffraction, transmission electron microscopy, atomic force microscopy, spectroscopic ellipsometry, UV–visible spectroscopy and nanoindentation. The X-ray diffraction studies showed that the films deposited at low substrate temperatures (300–673 K) were amorphous Al 2 O 3 , whereas those deposited at higher temperatures (≥773 K) were polycrystalline cubic γ -Al 2 O 3 . The transmission electron microscopy studies of the film prepared at 673 K, showed diffuse ring pattern indicating the amorphous nature of Al 2 O 3 . The surface morphology of the films was examined by atomic force microscopy showing dense and uniform nanostructures with increased surface roughness from 0.3 to 2.3 nm with increasing substrate temperature. The optical studies were carried out by ellipsometry in the energy range 1.5–5.5 eV and revealed that the refractive index increased from 1.69 to 1.75 ( λ =632.8 nm) with increasing substrate temperature. The UV–visible spectroscopy analysis indicated higher transmittance (>80%) for all the films. Nanoindentation studies revealed the hardness values of 20.8 and 24.7 GPa for the films prepared at 300 K and 973 K respectively.

Cerium oxide (CeO 2 ) thin films were deposited on Si (100) and glass substrates at various oxygen partial pressures (2×10 −5 mbar–3×10 −1 mbar) and a substrate temperature of 673 K, by pulsed laser deposition (PLD). The structural, morphological and optical properties of the films were characterized by X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, atomic force microscopy, photoluminescence and UV–visible spectroscopy. XRD analysis revealed the polycrystalline and cubic structure of the CeO 2 films with preferred orientation for (200) as the increase of oxygen partial pressure. The Raman studies indicated the formation of Ce–O with the systematic variation of peak intensity and FWHM with oxygen partial pressures. The high resolution transmission electron microscopy investigation confirmed the polycrystalline and cubic nature of the CeO 2 films with (200) preferred orientation. The AFM studies showed the roughness (RMS) values of the films increased from 0.8 nm to 4.6 nm with increasing oxygen partial pressure from 2×10 −5 mbar to 3×10 −1 mbar. The photoluminescence (PL) investigation indicated the bandgap values in the range 3.05–3.10 eV with increasing oxygen partial pressures. The UV–visible spectroscopy analysis demonstrated that the refractive index of the films decreased from 2.41 to 1.72 with increasing oxygen partial pressures.

Several R&Ds are being performed for Korean helium cooled solid breeder (HCSB) test blanket module (TBM) in the field of hydrogen isotopes permeation characteristics measurement in the helium purge line, joining technologies of structural materials, breeder pebble materials development, and the measurement of pebble bed characteristics. Electron beam welding for reduced activated ferritic–martensitic (RAFM) steel is evaluated to find optimal welding conditions. Also, a hydrogen permeation measurement apparatus is newly installed for the evaluation of the permeation barrier characteristics of stainless steel and RAFM steels. Two fabrication methods of lithium orthosilicate pebbles are investigated using slurry droplet methods. As methods of silicon carbide coating on the graphite pebble, microwave coating and chemical vapor deposition coating are evaluated. Two apparatuses are established to assess the thermo-mechanical properties of graphite and breeder pebble beds. The current status of R&D activities on these areas is introduced and the main progresses are addressed in this paper.

R&D activities currently being undertaken for Korean Helium Cooled Solid Breeder (HCSB) Test Blanket Module (TBM) include joining technologies of structural materials, breeder pebble material development, and measurement of pebble bed characteristics. The joining performance of ferritic–martensitic steel is evaluated. TIG welding for ferritic–martensitic steel is evaluated to find welding conditions with two different current modes. The fabrication methods of lithium silicate powder and lithium titanate pebble are under development using special process. The Li2TiO3 pebbles showing an average diameter of 1.8 mm was fabricated by water-based sol–gel method. The Li4SiO4 powder with the particle size of about 200 nm was synthesized by PVA polymer solution method. The method of silicon carbide coating on the graphite pebble is investigated, and its possibility is verified based on the coating results on the graphite plate. Sputtered SiC coating layer was crystallized by high temperature heat treatment. The measurement method and database of the thermal properties of the pebble and pebble bed are important for the design of TBM as well as breeding blanket. The initial characteristics of the pebbles are assessed measuring the effective thermal diffusivity of graphite pebble by laser flash method.

Rudders of large container ships are easily affected by cavitation, which is well known to be induced by significant axial flows behind a propeller and discontinuities in the rudder. Among several methods to prevent or reduce the cavitation erosion occurred in the rudder, painting is gaining a lot of attention because it can be employed easily and cheaply. To conduct erosion tests properly, the simulation of heavily erosive cavitation is necessary. This can be generated using an inclined propeller dynamometer in the medium-size cavitation tunnel of MOERI (Maritime & Ocean Engineering Research Institute). The inclined shaft of the propeller creates strong cavitation, which occurs around the root of the propeller blade. This cavitation creates impacts through the collapsing process that are very severe, and are useful for realistic and efficient cavitation erosion tests. In the present study, the newly developed cavitation erosion test method is successfully employed to evaluate marine coatings that is mainly composed of epoxy elastomer or silicone polymer material. Silicone polymer-type paint B was found to have three times larger endurance than epoxy elastomer-type paint A.

Boron doped diamond films were synthesized on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) technique. The effect of B 2 O 3 concentration varied from 1000 to 5000 ppm on the field emission characteristics was examined. The surface morphology and quality of films were characterized by scanning electron microscope (SEM) and Raman spectroscopy. The surface morphology obtained by SEM showed variation from facetted microcrystal covered with nanometric grains to cauliflower of nanocrystalline diamond (NCD) particles with increasing B 2 O 3 concentration. The Raman spectra confirm the formation of NCD films. The field emission properties of NCD films were observed to improve upon increasing boron concentration. The values of the onset field and threshold field are observed to be as low as 0.36 and 0.08 V/μm, respectively. The field emission current stability investigated at the preset value of ∼1 μA is observed to be good, in each case. The enhanced field emission properties are attributed to the better electrical conductivity coupled with the nanometric features of the diamond films.

In this study, fatigue characteristics of C70S6 and SMA40 materials as a potential application in connecting rod for an Internal Combustion (IC) engine were investigated. An average fatigue life of 140,200 and 168,700 cycles and a fatigue limit of 432 and 437 MPa were determined for C70S6 and SMA40 specimens, respectively. However, when tested under the fretting condition, the fatigue lifetime was decreased by 77.8% and 20% and the fatigue limit was reduced to 96 and 350 MPa for C70S6 and SMA40 specimens, respectively. From the observations of fracture surfaces, it was confirmed that the fretting played a critical role in introducing many cracks at the initial stage of fatigue. It is clearly shown in this study that special attention should be given to the fatigue behavior of given materials under fretting condition to ensure reliable design and application of components in an automobile.

Various microstructural changes take place simultaneously during the mechanical alloying process. Reduction in the crystalline size and the lattice strain cause a significant peak broadening, and dissolution of solute atoms results in peak shift in X-ray diffraction (XRD) spectrum. Therefore application of conventional XRD analysis routes is not straight forward, and could lead to incorrect information. When XRD method is used to analyze MA’ed powders, the spectrum needs to be carefully interpreted in order to extract the meaningful quantitative information. In this study, the possible sources of the error are addressed when MA’ed powders of Al–X (X = Ti, Nb) system are characterized by the XRD method, and proper XRD analysis methods are suggested to determine on lattice parameter, solubility of minor elements, crystallite size and strain variance in the MA’ed Al–X samples. The TEM observation is done to evaluate the formation of solid solution during MA.

This study was designed to test that dietary conjugated linoleic acids (CLA) used in a mixture of cis-9,trans-11 and trans-10, cis-12 isomers (40% each in weight) coupled to poly(ethylene glycol) (PEG) as PEGylated CLA (PCLA) act as mediators inducing or inhibiting specific metabolic pathways in high-fat (HF)-fed obese C57BL/6J (ob/ob) mice. After an acclimatization period of 7 days, animals were given a normal (control) or HF diet, the latter being added either alone (HF) or with CLA, PEG or PCLA for 6 weeks. Although the food intakes were not different among the dietary groups, final body weights were significantly lower in the HF-PCLA group than in the HF group. Also the HF-PCLA diet strongly prevented the dramatic increase in blood low-density lipoprotein cholesterol observed with the HF diet, with no difference in high-density lipoprotein cholesterol between control, HF and HF-PCLA treatments. Furthermore, homeostasis model assessment levels showed a marked decrease in HF-PCLA-fed mice, preventing the increase found in mice fed the HF diet, and suggesting that PCLA lowered insulin resistance in HF-mice. The liver steatosis observed in mice fed the HF diet was also prevented by PCLA. Interestingly, the activity of mitochondrial glutathione peroxidase was increased by PCLA, which may enhance antioxidant defenses. Overall, PCLA exerted its beneficial effects through reduction of lipid accumulation and attenuation of insulin resistance induced by the HF diet in obese C57BL/6J (ob/ob) mice, which might confer to these products antiobesity properties in other species.

Cultural consensus analysis is a statistical method that can be used to assess participant responses to survey questions. The technique concurrently estimates the knowledge of each survey participant and estimates the culturally correct answer to each question asked, based on the existence of consensus among survey participants. The main objectives of this paper are to present the cultural consensus methodology and apply it to a set of median design and safety survey data that were collected using the Delphi method. A total of 21 Delphi survey participants were asked to answer research questions related to cross-median crashes. It was found that the Delphi panel had agreeable opinions with respect to the association of average daily traffic (ADT) and heavy vehicle percentage combination on the risk of cross-median crashes; relative importance of additional factors, other than ADT, median width, and crash history that may contribute to cross-median crashes; and, the relative importance of geometric factors that may be associated with the likelihood of cross-median crashes. Therefore, the findings from the cultural consensus analysis indicate that the expert panel selected to participate in the Delphi survey shared a common knowledge pool relative to the association between median design and safety. There were, however, diverse opinions regarding median barrier type and its preferred placement location. The panel showed a higher level of knowledge on the relative importance regarding the association of geometric factors on cross-median crashes likelihood than on other issues considered. The results of the cultural consensus analysis of the present median design and safety survey data could be used to design a focused field study of median safety.

It has long been recognized that leptin, a hormone made by adipocytes, is an important circulating signal for the regulation of body weight. In addition, matrix metalloproteinase (MMP), especially MMP-2, an adipocyte-secreted protein which promotes multi-cellular adipose clusters, is up-regulated in obesity. The present study is designed to evaluate whether trans-10,cis-12 conjugated linoleic acid (t-CLA) can suppress leptin-induced MMP-2 secretion in 3T3-L1 cells. The result showed that expressions of adipocyte marker proteins were significantly reduced by t-CLA-treated cultures, but not by linoleic acid (LA)-treated ones. Interestingly, MMP-2 secretion was significantly increased by leptin-treated cultures, thereby leading to accelerate adipocyte differentiation, indicating that MMP-2 was a necessary mediator of adipogenesis. However, increasing concentration of t-CLA significantly reduced leptin-induced MMP-2 secretion and triglyceride (TG) content. These findings provide support for a role for t-CLA in the regulation of metabolism in leptin-induced adipose tissue development.

The nucleation density of diamond films produced by microwave plasma enhanced chemical vapor deposition was enhanced up to four times using a cyclic methane flow modulation technique. In this technique, the plasma composition is alternated for short periods between a combination of methane and hydrogen and hydrogen only. This results in alternate periods of deposition and etching for the nucleation run. The highest nucleation density, 1.8×108 cm−2, was obtained for the highest methane:hydrogen ratio of 8:200 sccm at a growing/etching time ratio of 180/30 s for 10.5 min over 3 h total time on the glass substrates. The grain size likewise increased up to 0.85 μm with a higher growing/etching time ratio. In contrast, the diamond quality, as measured by the relative intensity of Raman peaks corresponding to diamond and amorphous carbon was inversely related with the growing/etching time ratio.

The effects of intra-abomasal infusion of a mixture of -casomorphins on circulating concentrations of insulin and glucose prestimulated by either abomasal (experiment 1) or intravenous (experiment 2) glucose were studied using non-lactating dairy cows. In both experiments, bolus infusion of 240 mg of a mixture of three beta-casomorphins (beta-casomorphin-4-amide, -5 and -7) was given via an abomasal infusion line. The beta-casomorphins significantly lowered the responses of serum insulin to both abomasal and intravenous glucose infusions (P