In this study, we analysed the influence of the flow and performance of the generated micro gas turbine with different rotational speeds. CFD analysis was also performed using commercial code called ANSYS CFX 14.5. It adopted the turbine of radial flow type suitable for power generation for small rotating equipment. The number of blades was designed with each radial turbine 8, vane nozzle 14. The boundary layer flow analysis was widely used to the SST model. Mass flow rate of the turbine was 1.45 kg/s. While the rpm varies from 38,000rpm to 48,000rpm under various boundary conditions, the distributions of Mach number and pressure were numerically analyzed for electric power output, turbine isentropic efficiency. We analyze the inlet pressure, outlet temperature, electric power output, turbine isentropic efficiency. It compared maximum and minimum revolution through CFD analysis. Power output of maximum revolution has been increased 18% more than minimum revolution. Isentropic efficiency of maximum revolution has been increased 16.5% more than minimum revolution. Therefore, maximum power output was 332kW, amaximum isentropic efficiency was 33.2%.

The present study deals with the effects of micro-alloying elements such as Ni, V, and Ti on the recrystallization behavior of carbon steels at different strain rates. Eight steel specimens were fabricated by varying the chemical composition and reheating temperature; then, a high-temperature compressive deformation test was conducted in order to investigate the relationship of the microstructure and the recrystallization behavior. The specimens containing micro-alloying elements had smaller prior austenite grain sizes than those of the other specimens, presumably due to the pinning effect of the formation of carbonitrides and AlN precipitates at the austenite grain boundaries. The high-temperature compressive deformation test results indicate that dynamic recrystallization behavior was suppressed in the specimens with micro-alloying elements, particularly at increased strain rate, because of the pinning effect of precipitates, grain boundary dragging and lattice misfit effects of solute atoms, although the strength increased with increasing strain rate.

The effect of PEMFC trapezoidal channel wall contact angle on water removal characteristics is investigated with the volume of fluid (VOF) method. Two different contact angles 60 and 90 degrees are selected. In the case of the side and top wall contact angle of 60 degrees, stable semi-spherical droplets move along the top wall slowly. In contrast, complex shaped droplets move along the lower edge in the case of 90 degrees. Moreover, it is shown that very complex interaction patterns between different droplets which introduced into the channel at different times.

In this work, we studied the effects of electrochemical oxidation treatments of carbon fibers (CFs) on interfacial adhesion between CF and epoxy resin with various current densities. The surface morphologies and properties of the CFs before and after electrochemical-oxidation-treatment were characterized using field emission scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and single-fiber contact angle. The mechanical interfacial shear strength of the CFs/epoxy matrix composites was investigated by using a micro-bond method. From the results, electrochemical oxidation treatment introduced oxygen functional groups and increased roughness on the fiber surface. The mechanical interfacial adhesion strength also showed higher values than that of an untreated CF-reinforced composite.

In this study, i machined micro hole to PCB(Printed circuit board) with ultra precision spindle system for mechanical micro drilling. For this i utilized 0.4∼0.6 ㎜ micro drill and observed cutting edge and hole. Results are as follows; in case of drilling with 0.4∼0.6 ㎜ micro drill, micro hole was made specific range of diameter up to 300 times drilling and micro drilled diameter was bigger than micro drill’s diameter at 300 times over. Error ratio of drilled diameter and damaged hole diameter was within 5 % and 17 %. I observed 0.4 ㎜and 0.6 ㎜micro drill’s cutting edge after 500 times drilling and confirm cutting edge width variation and damage, same result found 1000 times drilling with 0.5 ㎜ micro drill.

Ni(OH)2 hollow spheres have been prepared by solvent displacement crystallization using a micro-injection device, and the effect of process parameters such as concentration and the relative ratio of the injection speed of the precursor solution, which is an aqueous solution of NiSO4·6H2O, to isopropyl alcohol of displacement solvent have been investigated. The crystal phases after NaOH treatment are in the β-phase for all process parameters. A higher concentration of NiSO4·6H2O aqueous solution is injected by a micro-injection device and bigger Ni(OH)2 hollow spheres with a narrower particle size distribution are formed. The crystallinity and hardness of the as-obtained powder are so poor that hydrothermal treatment of the as-obtained Ni(OH)2 at 120oC for 24 h in distilled water is performed in order to greatly improve the crystallinity. It is thought that a relative ratio of the injection speed of NiSO4·6H2O to that of isopropyl alcohol of at least more than 1 is preferable to synthesize Ni(OH)2 hollow spheres. It is confirmed that this solution- based process is very effective in synthesizing ceramic hollow spheres by simple adjustment of the process parameters such as the concentration and the injection speed.

Magnetostrictive actuator is fabricated with powder nano bonding method instead of sputtering method. Fabrication process and experimental measurement method for magneto-mechanical characteristics is proposed. For the design of highly flexible magnetostrictive actuator, TbDyFe nano powder bonding with Teflon substrate is adopted. The fabrication process for Teflon substrate and nano powder bonding is suggested and magnetostrictive behaviors are investigated. Variable magnetic field is applied to measure the magnetostrictive characteristics and magnetostriction is measured with different waves and different magnitude of magnetic field.

Because of environmental and resource depletion issue, there is a growing interest in eco-friendly vehicle, especially electric car. The small electric city car, called "Micro Mobility" has gained in popularity because of generalization of households under two or less members. In this study, to improve mechanical characteristics of Micron Mobility, 2-speed planetary transmission is designed, manufactured, and its efficiency is verified.

This is to develop a micro water turbine which makes some power from just a fluid velocity in the water pipe. While power is produced from impulsive force which generated by a high head in the case of existing water turbine, this is to produce a power from rotating force of helical turbine which rotated by fluid velocity in the water pipe. Some results of analysis fluid pattern at turbine blade for design shows that bubble is generated from turbulence surrounding blade and pulsatory motion generated as fluid being blocked and opened by blade due to turbine structure. This two phenomena cause to lower power production efficiency and shorten turbine durability. So this is studied to minimize bubble generation and pulsation for optimizing design of turbine blade. Therefore it is determined that the number of blade is three, geometric form of blade is NACA 4420 and angle of blade is 30 degree. An experiment equipment of water turbine is manufactured on the base of these factors(NACA 4420, angle 30。). It is obtained that power production of turbine increases in proportion to velocity which is changed from 1.7 m/sec to 3.5 m/sec. When fluid velocity is 1.7m/sec the power production of turbine is 355W. Power production increase continuously as increasing the fluid velocity and power is 2kW on 3m/sec of fluid velocity.

Xenotransplantation of pig islet regarded as a good alternative to allotransplantation. However, cellular death mediated by hypoxia-reoxygenation injury after transplantation disturb success of this technique. In the present study, we produce transgenic pig expressing human heme oxygenase 1 (HO1) genes to overcome cellular death for improving efficiency of islet xenotransplantation. Particularly, Korean miniature pig breed, Micro-Pig, was used in the present study. Somatic cell nuclear transfer (SCNT) technique was used to produce the HO1 transgenic pig. Six alive transgenic piglets were produced and all the transgenic pigs were founded to have transgene in their genomic DNA and the gene was expressed in all tested organs. Also, in vitro cultured fibroblasts derived from the HO1 transgenic pig showed low reactive oxygen species level, improved cell viability and reduced apoptosis level

The present study is the development of recyclable micro pale expansion drilling bit. The domestic market will gradually be suppressed by the new developed ring one in the use of ring bit(non-recyclable) in this business. Existing casing drilling and insertion method is applied by order of the casing inserted after drilling, which has the disadvantage that a long construction time, device costs and labor consuming. When the steel pipe multi-bit-only expansion drilling is developed, enterprise sales and employment effects can occur. If the performance of the developed products through the product equal to or superior to the domestic component parts are developed proprietary technology acquisition and cost savings, as well as the construction period of about 30%, and the expected reduction of 70% in material costs are expected.

풀무치(Locusta migratoria)는 단독형과 군집형을 보여주는 해충으로, 밀도가 높아지면 군집형으로 변하여 작물에 막대한 피해를 입힌다고 알려져 있음. 다양한 생태학적인 생리학적인 연구가 진행이 되어져 왔지만, 아직까지 국내에서 채집된 종에 대한 정확한 생리학적인 연구는 이루어지지 않았음. 국내 해남군 산이면에서 채집된 단독형과 군집형을 실험실에서 사육을 하여 전체 발현 유전체의 발현 변화 및 miRNA의 발현변화를 성별에 따라서 연구를 하였음. 동시에 무안군의 포장에서 채집된 야외 단독형과 중간형에 대한 전체 유전체 및 miRNA분석연구를 진행하고 있음. 이러한 연구는 현재까지 알려지지 않았던 풀무치의 군집형 형성기전 및 전이 기전에 대한 이해를 도울 것임.

Carbon micro particles with dimple patterns were produced by electro-spraying a solution of pitch in tetrahydrofuran. Particle formation depended on separation in an electrical field and volatilization of the solvent. More than 80% of the obtained carbon exhibited an average particle size of less than 50 μm. X-ray diffraction analysis suggests that the carbon with dimple patterns has increased crystallinity after heat treatment.

This research is to investigate the performance analysis of micro gas turbine for power generation with three different numbers of the nozzle vane in the micro gas turbine. Velocity, pressure. and temperature distributions of fluid over the flow domain of the turbine and turbulent kinetic energy of three different turbine blades are numerically calculated for the optimum design of turbine blade with two different rotational speeds of the turbine blade (10000 and 20000 RPM). Ultimately, the energy-efficient and maximum power-generated shape of the nozzle vane are determined through two different rotational speeds of the turbine with three shapes of the nozzle vane (6, 8, and 12 EA).

The optical film for light luminance improvement of back light unit that is used in light emitting diode/liquid crystal display and retro-reflective film is used as luminous sign consist of square and triangular pyramid structure pattern based on V-shape micro prism pattern. In this study, we analyzed machining characteristics of Cu-plated flat mold by shaping with diamond tool. First, cutting conditions were optimized as V-groove machining for the experiment of micro prism structure mold machining with prism pattern shape, cutting force and roughness. Second, the micro prism structure such as square and triangular pyramid pattern were machined by cross machining method with optimizing cutting conditions. Variation of Burr and chip shape were discussed by material properties and machining method.

국내 정수장 노후화의 가속과 더불어 신규 위험물질 및 미량유해물질에 대한 안전성 확보를 위하여 정수장의 고도화를 위한 노력이 지속되고 있으며, 막여과 기반의 고도정수처리 공정의 도입이 안전성 확보의 대안으로 자리잡고 있다. 그러나 원수의 특성을 고려한 막여과공정의 구성방안 및 운영방안 마련이 필요한 실정이다. 본 연구는 원수내 망간의 계절적 발현 특징을 나타내는 U정수장을 대상으로 500m³/일 용량의 정밀막여과를 기반으로 한 고도정수처리 테스트베드를 구축하고, 원수의 수질특성을 고려한 운영인자 확립과 더불어 처리효율을 평가하였다.

The performance of helical hydro turbine in water pipe line depends on the sectional shape of turbine blade, pitch angle of turbine blade, solidity and number of turbine blades, To investigate the effects of these design factors on the performance of helical hydro turbine, flow analysis was carried out by using commercial code ANSYS CFX version 14..5. From CFD analysis we obtained the optimum design factors which were the asymmetric blade shape of NACA4420, the pitch angle of 15 degrees and the solidity of 0.3. These results can be used for the actual design of sphere-shaped helical turbine in water pipe line.

This research is to investigate the flow characteristics of micropump with two different types of diffuser outlet in micropump (straight and round). Four different outlet diameters(1mm, 1.5mm, 2mm at straight type of diffuser outlet and single outlet diameter(1mm) at round type are utilized for the flow analysis of the diffuser in micropump. Velocity and pressure distributions of fluid over the flow domain are numerically calculated for the shape optimum design of diffuser in micropump with uniform inlet velocity and pressure. According to the calculations of local maximum pressure at diffuser outlet, straight type of diffuser with larger diameter of diffuser outlet is of highest flow energy performance of the flow channel shapes in the present micropump.

Copper is an essential micronutrient whose deficiency is often seen to occur in humans. Although many biomedical studies have focused on the use of nanoparticles, the nutritional effects of nano-sized copper oxide particles are not well known. This aim of this study was to investigate the nutritional bioavailability of nano- and micro-sized copper oxide (CuO) particles in copper-deficient (CuD) mice. Copper deficiency was induced in mice by feeding a CuD diet (0.93 mg Cu/kg diet) for 7 weeks. After the induction of copper deficiency, nano- or micro-sized copper oxide particles were administered orally at two different doses (0.8 and 4.0 mg CuO/kg body weight) to mice in the following groups: (1) normal control (NC), (2) CuD, (3) low dose micro-sized CuO, (4) high dose micro-sized CuO, (5) low dose nano-sized CuO, and (6) high dose nano-sized CuO. The hepatic copper concentration in the CuD group was significantly lower than that in the NC group. Compared to the NC group, the CuD group exhibited lower serum ceruloplasmin (CP) activity and CP level. The copper/zinc-superoxide dismutase activity in the CuD group was significantly lower than that in the NC group. Treatment with nano- or micro-sized copper oxide particles for 2 weeks restored the hepatic copper levels and serum CP activities to values similar to those observed in the NC group. The CP levels and copper/zinc-superoxide dismutase activities in all the copper oxide treatment groups also recovered to normal values after 3 weeks of copper oxide treatment. These results show that oral administration of either nano- or micro-sized copper oxide particles for 2–3 weeks restored the normal condition in previously CuD mice.