• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.11
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• pp.942-948
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• 2007

Popular techniques for producing hydrogen by converting methane include steam reforming and catalyst reforming. However, these are high temperature and high pressure processes limited by equipment, cost and difficulty of operation. Low temperature plasma is projected to be a technique that can be used to produce high concentration hydrogen from methane. It is suitable for miniaturization and fur application in other technologies. In this research, the effect of changing each of the following variables was studied using an AC GlidArc system that was conceived by the research team: the gas components ratio, the gas flow rate, the catalyst reactor temperature and voltage. Results were obtained for methane and hydrogen yields and intermediate products. The system used in this research consisted of 3 electrodes and an AC power source. In this study, air was added fur the partial oxidation reaction of methane. The result showed that as the gas flow rate, the catalyst reactor temperature and the electric power increased, the methane conversion rate and the hydrogen concentration also increased. With $O_2/C$ ratio of 0.45, input flow rate of 4.9 l/min and power supply of 1 kW as the reference condition, the methane conversion rate, the high hydrogen selectivity and the reformer energy density were 69.2%, 32.6% and 35.2% respectively.

• Journal of Hydrogen and New Energy
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• v.18 no.2
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• pp.132-139
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• 2007

Popular techniques for producing synthesis gas by converting methane include steam reforming and catalyst reforming. However, these are high temperature and high pressure processes limited by equipment, cost and difficulty of operation. Low temperature plasma is projected to be a technique that can be used to produce high concentration hydrogen from methane. It is suitable for miniaturization and for application in other technologies. In this research, the effect of changing each of the following variables was studied using an AC Glidarc system that was conceived by the research team: the gas components ratio, the gas flow rate, the catalyst reactor temperature and voltage. Glidarc plasma reformer was consisted of 3 electrodes and an AC power source. And air was added for the partial oxidation reaction of methane. The result showed that as the gas flow rate, the catalyst reactor temperature and the electric power increased, the methane conversion rate and the hydrogen concentration also increased. With $O_2/C$ ratio of 0.45, input flow rate of 4.9 l/min and power supply of 1 kW as the reference condition, the methane conversion rate, the high hydrogen selectivity and the reformer energy density were 69.2%, 36.2% and 35.2% respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.843-848
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• 2017

Metal exposed to high temperature/high pressure/oxidizer-rich environment may cause rapid oxidation(ignition and combustion). In this study, a DC power supply test system that controls the temperature of specimen by supplying power to the specimen was constructed and after simulating the high temperature/stagnation/oxidizer-rich environment, the metal oxidation and ignition of STS series metal materials were evaluated. As a result, we was confirmed that the deformation (discoloration) of the selected material, the change in the surface roughness and the peeling of the metal surface were observed, and that the weight and the specimen thickness were changed. The most oxidized specimen was STS 304 and the less oxidized specimen was XM-19.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.100-106
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• 2014

High strength concrete has a structural advantage as well as superior usability and durability, so that its application in building is being steadily augmented. However, in the high temperature like in a fire, the high strength concrete has extreme danger named explosive spalling. It is known that the major cause of explosive spalling is water vapour pressure inside concrete. General solution for preventing concrete from spalling include applying fire protection coats to concrete in order to control the rising temperature of members in case of fire. The purpose of this study is to investigate the high temperature properties of fireproof mortar using organic fiber and various types of fine aggregate for fire protection covering material. The results showed that addition of perlite and polypropylene fiber to mortar modifies its pore structure and reduces its density. This causes the internal temperature to rise. As a results, it is found that a new fireproof mortar can be used in the fire protection covering material in high strength concrete.

• The Journal of Korean Medicine
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• v.21 no.1
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• pp.62-67
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• 2000

Background and Purpose: Sybsun-points are located at the tips of all fingers, 0.1chon from the finger nails, totaling 10 points on both hands. These points have been used for emergency care, fainting, epilepsy, cerebrovascular accidents, hypertension, unconsciousness, high fever etc. The most common technique is bleeding with a needle at these points. Hypertension and fever are the main factors for stroke patients’progress. We investigated whether venesection at Sybsun-points has effects on blood pressure and body temperature in stroke patients. Materials and Methods: 79 stroke patients were enrolled in this study from 1 Jan. 1999 to 30 Sep. 1999. All of them were admitted in Kyunghee University, Hospital of Oriental Medicine. Among them, 62 patients were hypertensive people, 17 were normal. Among the hypertensive patients, 27 were stage 1,20 were stage 2, 15 were stage 3 by classification of JNC 1997. All of the hypertensive patients had been taking drugs, while the normal group did not. From 2pm to 3pm, every 30 minutes we checked patients' blood pressure and body temperature by 24ABPM and tympanic thermometer. After 30 minutes passed, we phlebotomized patients Sybsun-points with Samneung needle 2-3cc of blood. Right after the bleeding, we checked blood pressure and body temperature. After the bleeding, for the next hour and a half, we checked each patient’s blood pressure and body temperature every thirty minutes, or a total of three times. We compared the blood pressure and the body temperature before and after treatment(p<0.05). Results: 1. Venesection at Sybsun-points significantly decreased systolic blood pressure on stage 3 hypertensive patients(p<0.0l). 2. Venesection at Sybsun-points significantly decreased diastolic blood pressure on stage 3 hypertensive patients(p<0.05) 3. Venesection at Sybsun-points had no effect on the change of body temperature. Conclusions: Though further study is needed, our findings suggest that Venesection at Sybsun-points may alleviate hypertension in stroke patients.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.202-202
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• 2002

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.221-221
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• 1999

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.285-285
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• 2002

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.154.1-154
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• 2002

• Korean Journal of Materials Research
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• v.30 no.3
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• pp.142-148
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• 2020

Graphene has attracted the interest of many researchers due to various its advantages such as high mobility, high transparency, and strong mechanical strength. However, large-area graphene is grown at high temperatures of about 1,000 ℃ and must be transferred to various substrates for various applications. As a result, transferred graphene shows many defects such as wrinkles/ripples and cracks that happen during the transfer process. In this study, we address transfer-free, large-scale, and high-quality monolayer graphene. Monolayer graphene was grown at low temperatures on Ti (10nm)-buffered Si (001) and PET substrates via plasma-assisted thermal chemical vapor deposition (PATCVD). The graphene area is small at low mTorr range of operating pressure, while 4 × 4 ㎠ scale graphene is grown at high working pressures from 1.5 to 1.8 Torr. Four-inch wafer scale graphene growth is achieved at growth conditions of 1.8 Torr working pressure and 150 ℃ growth temperature. The monolayer graphene that is grown directly on the Ti-buffer layer reveals a transparency of 97.4 % at a wavelength of 550 nm, a carrier mobility of about 7,000 ㎠/V×s, and a sheet resistance of 98 W/□. Transfer-free, large-scale, high-quality monolayer graphene can be applied to flexible and stretchable electronic devices.