In this study, the ternary Ge–Sb–Se chalcogenide glass was fabricated by a standard melt-quenching technique for flexible infrared lenses. Chalcogenide glass should have unique thermal and mechanical properties to be applied to precision glass molding (PGM) process. Therefore, the relations between thermal properties and the moldability were investigated for (35–20)Ge–(5–20)Sb–60Se glass systems. The thermal and thermos-mechanical properties were characterized by the differential scanning calorimeter and thermos-mechanical analysis, respectively. Preceding experiments using a pressing tester were conducted before PGM process to evaluate the moldability. The surface condition of both chalcogenide glass disks and Tungsten Carbide (WC) molds were characterized by using an optical microscopy and an interferometer. The preferential compositions in (35–20)Ge–(5–20)Sb–60Se glass systems were selected to produce molded lenses. Finally, the molded chalcogenide lens was successfully fabricated using the preferential compositions and the processing conditions from the preceding experiments using a pressing tester.

Stream development can generate environmental changes that impact fish communities. In temperate streams, the distribution of fish species is associated with environmental gradients. To analyze the relevant factors, large-scale exploration is required. Thus, to evaluate the distribution patterns of fish in Korea, sampling was conducted on a national scale at 720 sites over a 6-week period in 2009. A total of 124 fish species in 27 families were identified; Zacco platypus and Zacco koreanus of the Cyprinidae were the dominant and subdominant species, respectively. Of the species found, 46 (37.1%) were endemic and 4 (3.2%) exotic; of the latter, Micropterus salmoides and Lepomis macrochirus were widely distributed. Upon canonical correspondence analysis (CCA), both altitude and biological oxygen demand (BOD) were highly correlated with CCA axes 1 and 2, respectively. This explained 62.5% of the species–environment relationship. Altitude and stream order were longitudinally related to species distribution. The numbers of both total and endemic species gradually increased as streams grew in size to the fourth–fifth-order, and decreased in sixth-order, streams. Overall, fish communities were stable throughout the entire watershed, whereas some species showed site-specific occurrence patterns due to the paleogeomorphological characteristics of Korean peninsula. However, various anthropogenic activities may negatively affect fish communities. Therefore, both short- and long-term sustainable management strategies are required to conserve native fish fauna.

Oxidation-induced stress evolutions in Ta thin films were investigated using ex situ microstructure analyses and in situ wafer curvature measurements. It was revealed that Ta thin films are oxidized to a crystalline TaO2 layer, which is subsequently oxidized to an amorphous tantalum pentoxide (a-Ta2O5) layer. Initial layered oxidation from Ta to TaO2 phases abruptly induces high compressive stress up to about 3.5 GPa with fast diffusion of oxygen through the Ta layer. Subsequently, it is followed by stress relaxation with the oxidation time, which is related to the slow oxidation from TaO2 to Ta2O5 phases. The initial compressive stress originates from the molar volume expansion during the layered formation of TaO2 from the Ta layer, while the relaxation of the compressive stresses is ascribed to the amorphous character of the a-Ta2O5 layer. According to Kissinger's analysis of the stress evolution during an isochronic heating process, the oxygen diffusion process through the a-Ta2O5 layer is the rate-controlling stage in the layered oxidation process of forming a a-Ta2O5/TaO2/Ta multilayer and has an activation energy of about 190.8 kJ/mol.

We present growth of vertically aligned carbon nanotube (VCNT) on metal substrates such as Cu foils, Inconel 600 and stainless steel (SUS316L) using thermal chemical vapor deposition (TCVD) in order to get a low contact resistance at interface between CNT and substrates for future applications. The temperature range for VCNT growth was 700-775 °C and mixtures of acetylene, argon and hydrogen were used as processing gas. The tube length was controlled by growth time and temperature. Finally, we successfully grew the VCNT on Cu foils over 1 cm2 and confirmed the excellent electrical conductance which can be directly used as anodic electrode in lithium ion battery. On the other hand, the growth of VCNT on Inconel 600 or SUS316L sheets was carried out as purchased. These tubes are expected to be useful for field emission devices.

The sap of Acer mono has been called ‘bone-benefit-water’ in Korea because of its mineral and sugar content. In particular, the calcium concentration of the sap of A. mono is 37·5 times higher than commercial spring water. In the current study, we examined whether A. mono sap could improve or prevent osteoporosis-like symptoms in a mouse model. Male mice (3 weeks old) were fed a low-calcium diet supplemented with 25, 50 or 100 % A. mono sap, commercial spring water or a high calcium-containing solution as a beverage for 7 weeks. There were no differences in weekly weight gain and food intake among all the groups. Mice that were given a low-calcium diet supplemented with commercial spring water developed osteoporosis-like symptoms. To assess the effect of sap on osteoporosis-like symptoms, we examined serum calcium concentration, and femur density and length, and carried out a histological examination. Serum calcium levels were significantly lower in mice that received a low-calcium diet supplemented with commercial spring water (the negative control group), and in the 25 % sap group compared to mice fed a normal diet, but were normal in the 50 and 100 % sap and high-calcium solution groups. Femur density and length were significantly reduced in the negative control and 25 % sap groups. These results indicate that a 50 % sap solution can mitigate osteoporosis-like symptoms induced by a low-calcium diet. We also examined the regulation of expression of calcium-processing genes in the duodenum and kidney. Duodenal TRPV6 and renal calbindin-D9k were up-regulated dose-dependently by sap, and the levels of these factors were higher than those attained in the spring water-treated control. The results demonstrate that the sap of A. mono ameliorates the low bone density induced by a low-calcium diet, most likely by increasing calcium ion absorption.

Ceria doped-yttrium aluminum garnet (Y3Al5O12:Ce3+, YAG:Ce), which is known as an efficient phosphor, have been widely used in optical display and lighting applications. Improved wet chemical method, sol-gel, has been studied, since conventional solid-state reaction requires a high-temperature and prolonged heating to obtain the pure phase. However, there has been little information, such as on pre-firing temperature, concerning high-quality powder formed by the wet chemical process. In this work, YAG:Ce was synthesized with a salted sol-gel process in which a water solution of inorganic salt with citric acid as additive. Transparent starting sol was pre-fired at 200 ˜ 300°C for 2 hrs in air and final annealing to obtain phase-pure YAG:Ce particles was performed at 1100°C for 2 hrs in argon. The effects of pre-firing temperatures on the crystal structure, morphology and luminescence were investigated. Effects of residual organics in the pre-fired gel on the properties of finally annealed phosphors will be fully discussed on the basis of the results of thermal analysis and chemical structure.

In this study, we have investigated microencapsulation of magenta, yellow, and cyan color polymer balls with white pigment for multi-color electrophoretic display implementation. The charged color pigments have been prepared by physical coating of magenta, yellow, and cyan with functionalized polymers, then surface charging with charge control agent. These color balls with white pigment were microencapsulated in suspending fluid through in-situ polymerization.

Strip-shaped diamond-tip field emitter array was fabricated by using the transfer mold technique. The sharp turn-on characteristic was observed from the current-voltage measurement of the fabricated diamond-tip field emitter array. The turn-on characteristic of the diamond-tip field emitter array was compared with that of a flat diamond film. High emission current density was obtained from the diamond-tip field emitter array. The threshold voltage of the diamond-tip field emitter array was lower than that of a flat diamond film.