• Journal of ILASS-Korea
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• v.17 no.3
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• pp.146-151
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• 2012

This study was primarily focused on the experimental comparison of the particle emission characteristics for heavy duty engine. PM and particle number from various heavy duty engines and DPF type were analyzed with a golden particle measurement system recommended by the Particle Measurement Program. And the repeatability and reproducibility between test mode was analyzed. This study was conducted for the experimental comparison on particulate emission characteristics between the European and World-Harmonized test cycles for a heavy-duty diesel engine. To verify the particulate mass and particle number concentrations from various operating modes, ETC/ESC and WHTC/WHSC, both of which will be enacted in Euro VI emission legislation, were evaluated. Real-time particle formation of the transient cycles ETC and WHTC were strongly correlated with engine operating conditions and after-treatment device temperature. A higher particle number concentration during the ESC mode was ascribed to passive DPF regeneration and the thermal release of low volatile particles at high exhaust temperature conditions.

• Journal of the Korean Chemical Society
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• v.46 no.2
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• pp.117-124
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• 2002

Counterflow oxidation was developed and evaluated for treatment of organics that adsorbed in/on granular activated carbon(GAC). This reaction is a method that destructs and removes organics adsorbed, at the same time, regenerates waste carbon, uti lizing a self-sustained flame which propagates itself ina direction counter to the oxygen flow. The results showed that the mass loss of carbon and flam temperature were strongly dependent on the flow rate of oxyen, adsorptive capability of regenerated carbon completely was recovered, as well as destrution and removal efficiency of thermally stable PCBs was achieved with the value of better than 99.99%.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.543-551
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• 2007

The performance characteristics of water-chilling heat pump using $CO_2$ with respect to variation of inlet temperature and mass flow rate of secondary fluid was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter-flow-type heat exchangers with concentric dual tubes, which ate made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2.4 m length. The experimental results were summarized as the followings : As inlet temperature of secondary fluid in the gas cooler increases from $10^{\circ}C$ to $40^{\circ}C$, the compressor work, heating capacity and heating COP were varied to 37.8%, -13%, -35.9%, respectively. The heating capacity, compressor work, heating COP were turned into 23.3%, 6.42%, 13.1%, respectively when ass flow rate of secondary fluid in the evaporator increases from 70 g/s to 150 g/s. The above tendency is similar with performance variation with respect to temperature variation of secondary fluid in the conventional vapor compression cycle.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.558-566
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• 2007

The performance characteristics of water-chilling heat pump using $CO_2$ with respect to variation of refrigerant charge amount was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter-flow-type heat exchangers with concentric dual tubes, which are made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2400 mm length. The experimental results summarize as the followings : As the refrigerant charge ratio of $CO_2$ heat pump system increases, the discharge pressure and compressor ratio increases, but mass flow rate of refrigerant decreases. Also the compressor work increases with the increase of refrigerant charge ratio. However, the heating and cooling capacity of $CO_2$ heat pump decreases as the refrigerant charge ratio increases. The maximum heating COP of $CO_2$ heat pump system presented at 0.25 refrigerant charge ratio. It is possible to confirm the optimum charge ratio of $CO_2$ heat pump system by the viewpoint of heating COP.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.378-385
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• 2012

Vent mixer can provide main flow directly into a recirculation region downstream of the mixer to enhance fuel-air mixing efficiency. Based on experimental results of three-dimensional velocity, vorticity and turbulent kinetic energy obtained by a stereoscopic PIV method, the performance of the vent mixer was compared with that of the step mixer which was used as a basic model. Thick shear layers of the vent mixer induced the increase of the penetration height. The turbulent kinetic energy mainly distributed along a boundary layer between the main flow and the jet plume. This turbulent field activates mass transfer in a mixing region, leading to the mixing enhancement.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.79-87
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• 2019

With desires for safe food, there is growing concern that pesticide spray drift will expose people, plants, and the environment to pesticide residue and potential negative effects thereof. For highly efficient, safe spray application, technologies for measuring the spray drift should be developed and improved with some urgency. This study investigated the applicability of two optical particle counters (OPCs), which are mostly used to measure airborne particle mass concentration, for measurement of airborne pesticide spray drift. Experiments were conducted in a controlled laboratory and an ash tree orchard to evaluate the handiness and accuracy of two OPCs, OPC 1 and OPC 2. The experimental results indicated that the OPC 1 was better applicable to the measurement of spray drift in the field while the use of the OPC 2 was limited due to its narrow range of measurable droplet sizes. The readings of the OPC 1 produced highly accurate results ($R^2=0.9637$) compared to the actual spray drift. For better application of OPCs, this study suggests the OPCs should be positioned properly to inhale spray droplets of the appropriate size and concentration.

• Journal of Radiation Protection and Research
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• v.35 no.3
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• pp.117-123
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• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• Korean Journal of Community Nutrition
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• v.11 no.3
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• pp.307-316
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• 2006

This study was conducted to investigate the relationships among body composition, dietary intake, and clinical blood indices in college students by body mass index (BMI). Their body compositions were determined by means of BIA (Bioelectrical Impedance Analysis) method. Their dietary intake was determined using a 3-day record method and their hematological indices were determined by semi-automated microcell counter (Sysmex F-520). Their serum lipid levels were measured using biochemical analyzer (Spotchem). Subjects were classified as underweight, normal or over-weight groups according to their BMI. The subjects were 69 healthy college students aged 20 to 26 years. The average age, height, weight, and BMI was 21.3 years, 162.6 cm, 54.4 kg, and $20.6cm/m^2$, respectively. Their average consumption of energy was 1693 kcal, 84.7% of RDA and their mean ratio of carbohydrate: protein: fat were 54.5 : 16.4 : 29.0. There was no significant difference in nutrient intake among the groups except ${\beta}$-carotene and vitamin C. The ${\beta}$-carotene intake was significantly higher in the underweight group. Vitamin C intake was significantly higher in the overweight group. The mean intakes of Ca, Fe, Zn and folate of subjects were 74.8% to 83.2% of RDA. Especially, intakes of Ca, Fe, Zn and folate were lower in the abnormal weight groups. The overall mean values of the hematological indices in female college students were within the normal range and there was no significant difference among the groups. However, anemic subjects with hemoglobin (< 12 g/dl) and hematocrit (< 36 g/dl) accounted for about 11% of the subjects. The everall mean values of the serum lipid levels were within the normal range and there was no significant difference among the groups. But serum HDL-cholesterol level of the overweight group was lower than that of the other groups. LDL-/HDL-cholesterol ratio and AI index were significantly higher in the overweight group compared to the other groups. Based upon this study, it is necessary for college women to be educated regarding consuming more Ca, Fe, Zn, folate and less fat and cholesterol in order to have better health promotion.

• Journal of Distribution Science
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• v.12 no.4
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• pp.47-54
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• 2014

Purpose - The postponement strategy, which delays the form, place, and production of products as late as possible, has been widely considered as a competitive supply chain management scheme in an era of mass customization and modular manufacturing. An interesting business phenomenon is that not all manufacturing/logistics firms choose the postponement strategy. Given that postponement is a counter-measure to speculation, which has some advantages under certain environments, the current imprudent inclination toward the postponement strategy may cause firms to lose the potential of the speculation strategy, an alternative strategy in supply chain management. Building on the logistics and manufacturing literature, this study examines characteristics of two contrasting strategies, postponement and speculation, and major factors favoring each strategy. Research design, data, and methodology - We apply the profiling approach to two business cases, HP printer and LG mobile phone. The profiling approach is a method of choosing a particular strategy aligned with environmental factors. While various approaches have been used to check the fit between a business strategy and environmental factors, the literature on manufacturing strategy and logistics has commonly adopted the profiling approach. Major factors used in profiling variables are derived from the literature. Two samples, HP printer and LG mobile phone, are selected, because they represent major characteristics appropriate for each strategy. The profiling is based on data from semi-organized interviews with managers. Results - The profiling approach shows that the postponement strategy is a suitable one for HP printers. Most factors, such as product life cycle, large production volume, low-price, product value, and monetary density, support delaying end products until as late as possible. Despite some exceptions, such as delivery time and economy of scale, our analysis states that the overall profile of HP printer is favorable for the postponement strategy. On the other hand, LG mobile phone may adapt the speculation strategy. Although it has large production volume and low delivery frequency, most characteristics support the speculation strategy for this product. An interesting finding is that, despite common perception that advanced technology products such as mobile telephones favor the postponement strategy, profiling proposes the speculation strategy for this product. Conclusions - Our analysis shows that speculation is not the universal option for supply chain management, and that, when choosing a specific strategy, one should consider many factors simultaneously. A major implication of our work is to emphasize the role of environmental factors such as supply chain variables in choosing an inventory strategy, and the importance of fit rather than solely strategic orientation. A theoretical contribution is to demonstrate the benefit of the simultaneous consideration of business variables in choosing specific strategies. For practitioners, our work leads us to consider the existence and the potential of speculation as a counter-measure to postponement. In addition, the comprehensive framework in this research may be instantly used in examining a practical strategy.

• Korean Security Journal
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• no.15
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• pp.337-358
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• 2008

With the Japanese attacks on Pearl Harbor in 1941, approximately 2,500 people were killed. The terrorist attack on World Trade Center in the United States resulted in the heavy loss of people's lives, 2,749 in all. The 9.11 demonstrated that terrorist attack could be more serious problem than the war in our modern life. In addition, terrorist armed with new and high technologies have become more dangerous elements to the international community. Especially, the fact that the weapons of mass destruction are used by terrorist organizations is a matter of great concern. The strength of terrorist arsenal gives terrorist a decided advantage over us. The chances of success for terrorist have been increased due to the terrorist friendly environments. Terrorism has evolved without stopping from its birth, which is imposing a great burden on the authorities concerned. The counter-terrorism strategy and tactics used in the past have been useless in the fighting against new terrorism. To cope with the fast changing terrorism, comprehensive countermeasures should be developed. The purpose of this study is to know the enemy. To achieve the goal, the current situation on international terrorism as a whole is examined. Based on the result of the research, this paper also tried to give a perspectives on the future terrorism. At the same time, it provides a guidelines of the direction in the fighting against terrorism.