• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.4
• /
• pp.8-14
• /
• 2015

This study has been done as a preliminary work in the process of confirming the modeling and calculation results on the dynamic characteristics of closed-type swirl injector which were performed by Ismailov et al. in Purdue university. Closed-type swirl injectors with replaceable swirl chamber parts were designed and manufactured. The steady state spray characteristics of closed-type swirl injector with varying swirl chamber length and diameter were verified. Mass flow rate was measured with a mass flow meter installed in front of the injector, and liquid film thickness was measured by Lefebvre's method with electrodes installed at the orifice of the injector. Variation of spray cone angle and break-up length were investigated from the spray images captured under different manifold pressure conditions.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.911-920
• /
• 2010

A closed-type erosion control dam were suggested as an effective method to protect from debris flow damages caused by seasonal rainstorm, typhoon, and local heavy rain. However, design method on a closed-type erosion control dam currently practiced in the engineering is not well established with respect to type of the dam, design parameters, maintenance and so forth. In this study, design parameters for closed-type erosion control dam were evaluated and the comparison of design parameters used in Korea and Japan was performed. Based on the results of this study, modification of design method for closed-type erosion control dam are recommended.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.897-902
• /
• 2007

The turnover-type sluice gate is typically actuated by the open circuit hydrauic system since the single-rod cylinder is used rather than the double-rod cylinder. However, here the closed circuit hydrauic system is applied for the operation of turnover-type sluice gate for the purpose of convenient operation. The closed circuit hydraulic system of turnover-type sluice gate is composed of a bi-directional pump, single-rod cylinders, pilot operated check valves, check valves and a counter balance valve. The usefulness of the closed circuit hydraulic system is verified for the several operational conditions by the computer simulations.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.34 no.5
• /
• pp.43-50
• /
• 2018

The temperature of underground water generally remains constant regardless of the season. therefore, it is possible to get plenty of energy if we use characteristics of underground water for both cooling and heating. This study evaluates efficiency of real size coaxial and U-tube type complex geothermal system which is combined with underground water well. This study also evaluates relative efficiency/adaptability through comparison with existing geothermal systems(vertical closed loop system, open loop system(SCW)). The heat exchange capacity of complex geothermal system according to temperature difference between circulating water and underground water shows very high significance by increasing proportionally. The temperature change of underground water according to injection energy, shows very high linear growth aspect as injection thermal volume heightens. As a result of evaluation of heat exchange volume between complex geothermal system and comparative geothermal system, coaxial type has 26.1 times greater efficiency than comparative vertical closed type and 2.8 times greater efficiency than SCW type. U-tube type has 26.5 tims greater efficiency than comparative vertical closed type and 2.8 times greater than SCW type as well. This means complex geothermal system has extremely outstanding performance.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.1
• /
• pp.197-207
• /
• 2015

A new communication revolution such as social networking service (SNS) has been transforming the way of interaction between people in both of individual level and organizational level. Recently many people have switched to closed type SNS such as Naver Band and Kakao group due to the several reasons. The purpose of this study is to investigate the usage motivation and satisfaction of closed type SNS based on use and gratifications perspectives. Based on prior studies on use and gratifications of Internet-related media and SNS, information motivation, relationship motivation, pleasure/entertainment motivation, self-expression motivation, work motivation were identified as usage motivation of closed type SNS. According to the results, relationship motivation and work motivation were found to be significantly related to the satisfaction. But other motivation factors(information motivation, pleasure/entertainment motivation, self-expression motivation) are not significantly related to the satisfaction. Then satisfaction was found to be significantly related to the intention to use. This study contributes to give companies providing closed type SNS and using it as a marketing tool with the base of activation strategies and practical implications.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.2
• /
• pp.181-192
• /
• 2015

A new communication revolution such as social networking service (SNS) has been transforming the way of interaction between people in both of individual level and organizational level. Recently many people have switched to closed type SNS such as Naver Band and Kakao group due to the several reasons. The purpose of this study is to investigate the usage motivation and satisfaction of SNS based on use and gratifications perspectives. Based on prior studies on use and gratifications of Internet-related media and SNS, information motivation, relationship motivation, pleasure/entertainment motivation, self-expression motivation, work motivation were identified as usage motivation of SNS. This empirical study explores how these motivations vary between open type SNS(facebook and twitter) and closed type SNS(band and kakao group). This study contributes to provide the base of activation strategies and practical implications for companies using SNS as a marketing tool.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.1
• /
• pp.39-47
• /
• 2006

Recent trend in pursuit of high performance and effectiveness for automotive cooling system has changed the application of material for impeller of automotive water pump from metal to high ability engineering resin, which can achieve optimization of design of impeller geometry and realize lightweight high efficiency water pump. Closed type water pump improves hydraulic loss of fluid through the clearance between volute casing and impeller compared with that of the existing open type water pump(Although closed type is heavier than open type for the same size and same material, adoption of plastics can solve the problem.). In the present study, the characteristics of hydraulic performance of closed type water pump were investigated with respect to the angle between shroud and hub of impeller and the shape of discharge port of volute casing. Performance tests were carried out for 4 cases, that is, for 2 impellers and 2 casings. The modification of shape of only discharge port can enhance the hydraulic performance by 10 percent and the pump efficiency by 4-6 percent.

• Journal of the Korean Society of Costume
• /
• v.53 no.6
• /
• pp.25-43
• /
• 2003

This study is to classify the types of Jikryung and to look into formative . periodic Characteristics. Results of analyzing can be described as follows. 1. Jikryung in the Chosun Era was classified according to whether it had a side hem. Jikryung which had side hem was reclassified according to the position of the side hem into inside, inside and outside and outside fold types and backward leaning type. Jikryung with no side hem was reclassified into types of closed and opened sides. 2. Concerning formative Characteristics, the type of inside fold was coexisted with the types of short front and long rear, the same front and rear, and narrow sleeves, bean chaff typed sleeves. Inside and outside fold type was used the type of short front and long rear, narrow sleeves. Outside fold type was used the type of same front and rear, bean chaff typed sleeves. Backward leaning type was used the same front and rear, wide sleeves. The types of closed and opened sides transformed from double Sup to single Sup and from narrow sleeves to bean chaff in its form and wide sleeves. 3. Concerning periodic Characteristics, the 1st period of Jikryung with side hem showed up the type of inside and outside fold, the 2nd period did the type of outside fold, The 3rd period did the type of backward leaning. Regarding Jikryung with no side hem, its 1st and 3rd periods saw the type of closed side, while its 2nd period coexisted with the types of closed and opened sides.

• Bulletin of the Korean Mathematical Society
• /
• v.31 no.1
• /
• pp.125-132
• /
• 1994

• Archives of Craniofacial Surgery
• /
• v.9 no.1
• /
• pp.12-16
• /
• 2008

Purpose: Closed reduction is most common treatment method for nasal bone fracture but it requires secondary correction operation commonly. For preventing secondary revision, we applied ultrasonography during closed reduction of nasal bone fracture and examined the result of operation. Methods: 80 patients were sorted into 2 groups, ultrasound-guided closed reduction group(n=40) and manual closed reduction group(n=40). We classified the unilateral fracture involving lower 1/2 of nasal bone into type I, the bilateral fracture involving lower 1/2 of nasal bone into type III and the fracture of upper 1/2 of nasal bone into type III. The occurrence rate of overcorrection and undercorrection were evaluated by comparing preoperative and postoperative MDCT(Multi Direction Computed Tomography). Results: In manual closed reduction group, overcorrection were found in 4 patients and undercorrection were found in 3 patients. In ultrasound-guided closed reduction group, overcorrection was not observed and undercorrection was observed in 2 patients. Conclusion: Intraoperative ultrasound evaluation of nasal bone fracture resulted in reduced occurrence rate of secondary nasal deformities, showed easier detection of the fractured site and have superiority upon simple physical examination or simple x-ray.