• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.158-165
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• 2008

The combustion and exhaust emissions characteristics of a liquefied petroleum gas-di-methyl ether compression ignition engine with a variable valve timing device were investigated under various liquefied petroleum gas injection timing conditions. Liquefied petroleum gas was used as the main fuel and was injected directly into the combustion chamber. Di-methyl ether was used as an ignition promoter and was injected into the intake port. Different liquefied petroleum gas injection timings were tested to verify the effects of the mixture homogeneity on the combustion and exhaust emission characteristics of the liquefied petroleum gas-di-methyl ether compression ignition engine. The average charge temperature was calculated to analyze the emission formation. The ringing intensity was used for analysis of knock characteristics. The combustion and exhaust emission characteristics differed significantly depending on the liquefied petroleum gas injection and intake valve open timings. The CO emission increased as the intake valve open and liquefied petroleum gas injection timings were retarded. However, the particulate matter emission decreased and the nitrogen oxide emission increased as the intake valve open timing was retarded in the diffusion combustion regime. Finally, the combustion efficiency decreased as the intake valve open and liquefied petroleum gas injection timings were retarded.

• Membrane Journal
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• v.25 no.4
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• pp.367-372
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• 2015

In pressure-retarded osmosis (PRO) and forward osmosis (FO) processes, solvent (permeate) flux depends on which surface the draw solution faces. There are two operation modes. PRO mode indicates that the active layer faces the draw solution, and FO mode means that the porous substrate fronts the draw stream. It is often observed that the PRO mode produces higher flux than that of FO under the same operating conditions. The current work uses the method of proof by contradiction, and mathematically proves the intrinsic flux inequality between the two modes.

• The Journal of Korean Association of Computer Education
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• v.5 no.4
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• pp.147-154
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• 2002

In this paper, we investigated the effects of response technique which uses free tokens in the computer training for the mentally retarded person. We set wrong line entering. wrong space number entering, wrong line-type designation and wrong cell merger as the target behaviors in the research. The experiment period of the research was 36 sessions altogether, and the period was divided into four steps such as basic period I. treatment period I, basic period II, and treatment period II. We also conducted a follow up experiment to identify whether the experiment's effect is still maintained two weeks after the experiment finished. We know that the response cost technique which uses free tokens to the mentally retarded person is efficient in the computer training.

• Journal of The Korean Dental Society of Anesthesiology
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• v.5 no.1 s.8
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• pp.22-24
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• 2005

General anesthesia is often required for mentally retarded children undergoing extensive dental treatment. We experienced a case of dental treatment under general anesthesia in a 14-year-old boy with mental retardation. He was treated on an outpatient basis. He was diagnosed of Noonan syndrome and received heart surgery when he was six years old. Induction using thiopental and vecuronium was uneventful and nasotracheal intubation were carried out. General anesthesia was maintained with sevoflurane for 2.5 hours. After monitoring the patient for 2 hours and confirming his recovery, he was discharged from the day care unit. In summary, we report this successful anesthetic management of a mentally retarded child during dental treatment in as an out-patient.

• Journal of Environmental Health Sciences
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• v.32 no.6
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• pp.560-565
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• 2006

Extract of DNA for analysis of fragile X syndrome is usually performed by blood, the researches using hair root as specimen have been gradually spread. In this study, analyze fra X gene of the patients in mentally retarded children facilities was conducted using hair root DNA with molecular biologic test (PCR). The number of total subjects was 24, boys were 12, the average age was $17({\pm}3)$, and girls were 12, the average age was $18({\pm}2)$. In girls, normal size of band of 222 bp appeared in all lanes. Also, in all lanes except control in 517 bp, micro band appeared. Moreover, with appearance of band of 1198bp in lanes 2, 3, 4, 5, it is estimated that it is the band of full mutation whose CGG repeated sequences are more than 200. But it showed the peculiarity that it appeared with normal band in all the same lanes, thus it is not reasonable to judge it is the band of full mutation and further studies are needed. These results appeared in 50%, 6 of 12 mentally retarded girls. As the result of mentally retarded boys, normal band appeared in about 222 bp in control, however in experiment group, normal band did not appear. In 43%, 7 out of 12 boys, band did not either appeared in 1198bp, which showed different patterns from that of girls.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.321-325
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• 2016

The Pressure Retarded Osmosis (PRO) is the next generation desalination technique and is considered as a eco-friendly energy. This was conducted to evaluate the effect of the temperature and pressure on the PRO performance. The flux of the permeation was measured under different operating conditions and estimated the power density. An improvement of PRO performance is depend on increasing solution temperature and optimum pressure. The effect of increasing feed solution temperature has stronger impact on the PRO performance comparing to the draw solution temperature. The reason of the results was due to the change of osmotic power, viscosity, water permeability and structure parameter(s).

• Communications of the Korean Mathematical Society
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• v.8 no.2
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• pp.289-301
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• 1993

• East Asian mathematical journal
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• v.8 no.2
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• pp.189-197
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• 1992

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.259-260
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• 2015

• Cement Symposium
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• no.22
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• pp.130-137
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• 1994