• Nuclear Engineering and Technology
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• v.41 no.8
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• pp.1127-1134
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• 2009

Concrete has three major properties after a penetration-reinforcing agent is applied on its surface. First, the durability is improved by the sol-gel process of synthesized material from the polycondensation of TEOS (tetra-ethoxyorthosilicate) and acrylate monomer. Second, the capability to absorb impact energy is reinforced through the formation of a soft and flexible layer of organic monomers by Tea (Tetra Ethyl Amin). Third, the capability to prevent deterioration is enhanced by adding isobutyl-orthosilicate and alcohol. The performance and application of an agent developed through the synthesis of organic and inorganic material in an effort to prevent concrete from deterioration and improve the durability of concrete structures were verified in diverse experiments. The results of these experiments showed that the application of the proposed penetration-reinforcing agent has the effect of increasing the compressive strength by filling up the internal pores of concrete with physically and chemically stable compounds after penetrating the concrete. It also improves the durability against the deterioration factors such as salt water damage, carbonation, freezing and thawing, and compound deterioration. Therefore, it is confirmed that the penetration-reinforcing agent is a useful substance for the management and repair of concrete structures.

• Journal of Welding and Joining
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• v.27 no.2
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• pp.63-68
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• 2009

Microminiature heat exchanger has been applied to the gas turbine in order to increase energy efficiency. During the production of microminiature heat exchanger, however, it is very difficult to weld tube to tubesheet. In this study, therefore, welding process of resistance ring projection was used, and weld tensile tests were performed. Sound weld joint was obtained as a result of applying resistance ring projection welding to microminiature heat exchanger to tubesheet. Cold weld occurred at under 1600A. Even though tensile strength was increased with increasing current, splash occurred and tensile strength decreased at 2000A due to the excessive current. Therefore it was determine that the optimal current is 1900A. As result of tensile tests based on ASME code for tube to tubesheet weldment, rupture position was weldment due to Fs(Fractured section) of nugget, which was smaller than tube thickness (t), and it was proven as a partial strength welding because of the average joint efficiency fr = 0.90.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.135-141
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• 2011

Recently, the more demand of reusable energy is globally increasing, the nationwide industry of wind power plants is more thriving. However, the level of native technology for operating wind power plants falls behind advanced countries. Thus, the most of management systems for wind power plants should be imported from the advanced countries. Additionally, advanced countries, which have possessed the controllable skills and consummate operating knowhow over decades, are blockading other countries which want to enter the market of wind power plants, and lead markets. This paper designs a prototype of HMI(Human Machine Interface) system which can effectively control and manage wind power plants.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.80-83
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• 2001

According to the EPA in Taiwan report, 9.05 million metric tons of solid wastes were generated in 1999, and the waste glass was accounted of 4.95 percent. However, with the increasing tonnage of disposal cost and existing disposal sites are reaching full capacity, recycling is currently accepted as a sustainable approach to waste management. Therefore, it's essential and urgent that the government in Taiwan establish the recycling and recovery framework for the minimization of the solid waste, reduction of materials and energy consumption, and the encouragement for the reuse, recycle and recovery development. To achieve this Boal, Taiwan has been strived for a long period of time in waste glass recovery and recycle. Waste glass, unlike other kinds of resource waste, is 100% recyclable. The EPA in Taiwan now center on a lot of different kinds of waste glass, such as glass container, flat glass, CRT glass, windshields glass, fluorescent lamps, and waste pesticide glass container. This article will focus on the framework of the recycling market access, and also try to provide some strategies to improve waste glass recycling efficiently.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.11.2-11.2
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• 2010

Photovoltaic devices are promising candidates as affordable and large-area renewable energy sources, which can replace the fossil-fuel-based resources. Especially, thin film solar cells have attracted increasing research attention, since they have a great advantage of low production cost. From the physical point of view, the photovoltaic devices can provide us interesting questions, how to enhance the light absorption and the carrier collection efficiency. A lot of approaches would be possible to address these issues. We have focused on two major topics relevant to photovoltaic device physics; (1) light management using surface plasmons and (2) junction characterizations aiming at proper interface engineering. Regarding the first topic, we have investigated the influences of Ag under-layer morphology on optical properties of ZnO thin films. The experimental results suggested that coupling between the surface plasmon polaritons at the ZnO/Ag interface and excitons in ZnO should play important roles in reflectivity of the ZnO/Ag thin films, which are widely used back reflector structures in thin film solar cells. For the second topic, we have carried out scanning probe microscopy studies of Schottky junctions consisting of photovoltaic materials. Such a research is very helpful to understand the correlation between the defects (e.g., grain boundaries) and local electrical properties. We will introduce some of the recent experimental results and discuss the physical significance.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.701-710
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• 1996

Composting has gained rapid acceptance as a method of recyling relatively dry organic materials such as leaves and brush and , when alternative disposal costs are high, even moist materials such as grass clippings and dewatered sewage sludges. However, as moisture contents rise above 60% , the need for a dry bulking amendment increase the costs of composting , both by direct purchases of amendment and though increased reactor capacity and materials handling requirements. High moisture materials also present increased risks of anaerobic odor formation through reduced oxygen transport (Miller , 1991) . These costs and operational challengers often constrain the opportunities to compost high moisture materials such as agricultural manures. During the last several decades economies of scale in livestock production have been increasing livestock densities and creating manure management challenges throughout the world. This issue is particularly pressing in Korea, where livestock arms typically manage little or no cropland, and the nutrients and boichemical oxygen demand in manure pose a serious threat to water quality. Composting has recently become popular as a means of recycling manure into products for sale off the farm, but bulking amendments (usually sawdust) are expensive designed to minimize bulking agent requirements by using the energy liberated by decompostion. In this context the composting reactor is used as a biological dryer, allowing the repeated use of bulking amendment with several batches of manure.

• Tribology and Lubricants
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• v.32 no.5
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• pp.166-171
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• 2016

Electric vehicle ownership is expanding for two reasons: its technology features have enhanced fuel economy, and the number of vehicle emissions regulations is increasing. Battery performance has a large influence on the capability of electric vehicles, and even though battery thermal management has been actively researched, specific technological improvements to battery performance are not being presented. For instance, many industrial applications utilize vortex tubes as components for refrigeration machines because of their numerous intrinsic benefits. If electric vehicles incorporate vortex tubes for battery cooling, performance and efficiency advancements are possible. This study uses a counter-flow vortex tube to investigate its temperature separation characteristics, based on the back pressure of the cold air exit and the difference between the inlet and back pressures. The experiment uses a vortex tube with the following parameters: six nozzle holes, a 20 mm inner vortex diameter (D), a 14D tube length, a 0.7D cold exit orifice diameter, and a nozzle area ratio of 0.142. The measurements prove that the temperature difference between the hot air and cold air decreased because of the flow resistance of the hot air and the backflow phenomenon at the cold air exit. The flow resistance causes the temperature difference to decrease, and the back pressure of the cold air exit influences the flow resistance. The results show that the back pressure significantly influences the efficiency of temperature separation.

• Proceedings of the IEEK Conference
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• summer
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• pp.204-208
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• 2004

Embedded business will be expanded market more and more since customers seek more wearable and ubiquitous systems. Cellular telephones, PDAs, notebooks and portable multimedia devices could bring higher microprocessor revenues and more rewarding improvements in performance and functions. Increasing battery capacity is still creeping along the roadmap. Until a small practical fuel cell becomes available, microprocessor developers must come up with power-reduction methods. According to MPR 2003, the instruction and data caches of ARM920T processor consume $44\%$ of total processor power. The rest of it is split into the power consumptions of the integer core, memory management units, bus interface unit and other essential CPU circuitry. And the relationships among CPU, peripherals and caches may change in the future. The processor working on higher operating frequency will exact larger cache RAM and consume more energy. In this paper, we propose advanced low power trace cache which caches traces of the dynamic instruction stream, and reduces cache access times. And we evaluate the performance of the trace cache and estimate the power of the trace cache, which is compared with conventional cache.

• Journal of the Korean Home Economics Association
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• v.39 no.6
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• pp.109-122
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• 2001

This study was performed to identify the roles of residents for the environmentally sound and sustainable development, taco-polis(kologisches Bauen), eco-village and Symbiotic Housing. These buildings will achieve energy efficiency through design strategies such as passive solar heating system, natural cooling and day lighting. Their infrastructure will feature parking on the periphery, extensive pedestrian paths, outdoor ground lights that preserve stellar visibility, and environmentally sensitive technologies such as low writer use fixtures. And they will restore biodiversity while protecting the wildlife, wetlands, forests, soil, air and water. Their houses wile be designed to support home-based occupations, offering high-speed Internet access and other options to promote a localized, sustainable economy. To support and encourage the evolution of sustainable settlements, it is necessary to prepare constructing the physical facilities and the social functions relating with residents. The roles of residents are important to provide a high Quality lifestyle and to integrate a supportive social environment with a low-impact way of life. This study concluded the four main roles of residents for the sustainable of Eco-polis and Ecovillage. 1. Residents assist transition towards a sustainable society as eco-conscious consumers in the planning stage. 2. Residents live in a ecological way for the sustainable ecovillage. 3. Residents exchange information and education for increasing the community glue as a communication network. 4. Residents support and transmit their cultural vitality and tradition for the next generation. So, users are expected to encourage resident's participation in the planning, design, ongoing management and maintenance of the sustainable ecovillage.

• Journal of Sensor Science and Technology
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• v.32 no.1
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• pp.39-43
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• 2023

Microscale thermophysical property measurements of liquids have been developed considering the increasing interest in the thermal management of cooling systems and energy storage/transportation systems. To accurately predict the heat transfer performance, information on the thermal conductivity, heat capacity, and density is required. However, a simultaneous analysis of the thermophysical properties of small-volume liquids has rarely been considered. Recently, we proposed a new methodology to simultaneously analyze the aforementioned three intrinsic properties using heater-integrated fluidic resonators (HFRs) in an atmospheric pressure environment comprising a microchannel, resistive heater/thermometer, and mechanical resonator. Typically, the thermal conductivity and volumetric heat capacity are measured based on a temperature response resulting from heating using a resistive thermometer, and the specific heat capacity can be obtained from the volumetric heat capacity by using a resonance densitometer. In this study, we analyze methods to improve the thermophysical property measurement performance using HFRs, focusing on the effect of the ambience around the sensor. The analytical method is validated using a numerical analysis, whose results agree well with preliminary experimental results. In a vacuum environment, the thermal conductivity measurement performance is enhanced, except for the thermal conductivity range of most gases, and the sensitivity of the specific heat capacity measurement is enhanced owing to an increase in the time constant.