• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.879-884
• /
• 2007

Flywheel energy storage systems have advantages over other types of energy storage devices in such aspects as unlimited charge/discharge cycles and environmental friendliness. In this paper we propose a millimeter scale flywheel energy storage device. The flywheel is supported by a pair of passive magnetic bearings and rotated by a toroidally wound electric motor/generator. The geometry of the bearings is optimized for the maximum dynamic performance.

• 전기의세계
• /
• v.13 no.3
• /
• pp.8-12
• /
• 1964

The study of the research for Random process have been recently increasing rapidly. There are many methods in generating of Random signal, however, mainly these are dependent upon utilizing of hot noise of resistance and noise of discharge tube. Consequently, it is not easy to obtain of Random Noise of stabilized low frequency. Therefore, I like to study over the result of principle and design in the method of obtaining the Random Noise with faint radiations of fluoresence materials.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.11
• /
• pp.1658-1665
• /
• 1989

Reactor design considerations over several critical parameters for a planar type reactive ion etcher are given. The etch uniformity is taken as a principal design constraint. The characteristics of economicaly available vacuum pumping system are taken as practical design constraints. A set of theoretical conditions on the chamber geometry and on the gas delivery and vacuum system, that satisfy the design constraints, are derived from basic properties of RF glow discharge and gas dynamics. The theoretical results are applied to decide design parameters of a practical single-wafer-per-chamber planar type reactive ion etching machine.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.701-707
• /
• 1999

This study was initiated to collect background pollutant data for rural watersheds. The effluent/run-off polutant load and run-off ratio of the study areas were calculated and the two types of regression equations, L=a$.$Q+b and L=c$.$Qd where L and Q are the pollutant load(L) and discharge (Q), were derived. We acquired that the correlation coeffcients of the two types of regression equations were over than 90% except for BOD . Therefore, L-Q equations would be a measure to predict water quality of rural watersheds.

• Journal of Korean Society of Disaster and Security
• /
• v.16 no.2
• /
• pp.15-32
• /
• 2023

There are some difficulties such as safety problem and need of manpower in measuring discharge by submerging the instruments because of many floating debris and very fast flow in the river during the flood season. As an alternative, microwave water surface current meters have been increasingly used these days, which are easy to measure the discharge in the field without contacting the water surface directly. But it is also hard to apply the method in the sudden and rapidly changing field conditions. Therefore, the estimation of the discharge using the surface velocity in flood conditions requires a theoretical and economical approach. In this study, the measurements from microwave water surface current meter and rating curve were collected and then analyzed by the discharge estimation method using the surface velocity. Generally, the measured and converted discharge are analyzed to be similar in all methods at a hydraulic radius of 3 m or over or a mean velocity of 2 ㎧ or more. Besides, the study computed the discharge by the index velocity method and the velocity profile method with the maximum surface velocity in the section where the maximum velocity occurs at the high water level range of the rating curve among the target locations. As a result, the mean relative error with the converted discharge was within 10%. That is, in flood season, the discharge estimation method using one maximum surface velocity measurement, index velocity method, and velocity profile method can be applied to develop high-level extrapolation, therefore, it is judged that the reliability for the range of extrapolation estimation could be improved. Therefore, the discharge estimation method using the surface velocity is expected to become a fast and efficient discharge measurement method during the flood season.

• Neonatal Medicine
• /
• v.17 no.1
• /
• pp.13-20
• /
• 2010

Purpose : Because infants who have been hospitalized in the neonatal intensive care unit (NICU) are usually ill or premature, they are hospitalized repeatedly after their discharge. We intended to survey the frequencies and the medical costs of those rehospitalizations. Methods : The NICUs of 7 major hospitals were included. The subjects were 3,451 infants that were admitted to the NICU from July 2005 to June 2006, and discharged to home. The frequency, causes, mean cost and distribution and proportion of National Health Insurance coverage and non covered costs were analyzed. Results : The rate of rehospitalization after discharge from the NICU over 1 year was 14.8%. If multiple cases are considered as individual cases, it is 21.7%. The major causes of admission were pneumonia (15.8%), bronchiolitis (14.5%), gastroenteritis (10.4%), urinary tract infection (6.3%) and sepsis (6.3%). The mean cost for each admission was 1,652 thousand won. The mean cost of National Health Insurance coverage was 1,170 thousand won and non covered coat were 472 thousand won 70.9% and 28.6% respectively. Conclusion : The ratio of rehospitalization of infants after their discharge from the NICU over 1 year was approximately 20% and it means that follow-up management of these infants is very important and meticulous concerns after discharge should be given. However the rehospitalization and the non-coverage proportion of National Health Insurance cost is considerably high. It strongly implies that National Health Insurance should cover much more proportion, and personal cost exemption should be proceeded in case of rehospitalization of infants after discharge from the NICU.

• 한국전산유체공학회:학술대회논문집
• /
• 2000.05a
• /
• pp.14-19
• /
• 2000

A coupled general circulation model (GCM) of the global atmosphere, oceans and lands is used for finding the future climate at times of doubled carbon dioxide concentration (DCDC) of the atmosphere. Two runs of the model were made in order to find the future change. Global changes at times of DCDC may be characterized by a global warmig of $1.4^{\circ}C$, a $3\%$ global precipitation increase, and an increase in the surface available water (SAW) over the global land among others. The estimated increase in SAW over the land implies that river discharge is likely to increase with increased chance of severe weather as a result of the future global warming.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.5
• /
• pp.340-344
• /
• 2012

Protected Circuit Module protects battery from over-charge and over-discharge, also prevents accidental explosion. Therefore, power MOSFET is essential to operate as a switch within the module. To reduce power loss of MOSFET, the on state voltage drop should be lowered and the switching time should be shorted. However there is trade-off between the breakdown voltage and the on state voltage drop. The TDMOS can reduce the on state voltage drop. In this paper, effect of design parameter variation on electrical properties of TDMOS, were analyzed by computer simulation. According to the analyzed results, the optimization was performed to get 65% higher breakdown voltage and 17.4% on resistance enhancement.

• Ocean and Polar Research
• /
• v.25 no.1
• /
• pp.1-7
• /
• 2003

The purpose of this study was to determine changes in the growth rates and the degree of shell bioerosion exhibited by endolithic organisms of the Japanese scallop family, Patinopecten (Mizuhopecten) yessoensis, on the coast of Furugelm Island (Peter the Great Bay, northwest of East Sea = Sea of Japan) over the last three decades. The areas studied are affected by lumen (Tumangang) River run-off, which is enriched by organic matter and polluting agents. It was found that the linear growth rates of the Japanese scallops living along the coasts of Furugelm Island have decreased over the last three decades. The degree of bioerosion of scallop shells has significantly increased for the same period. These phenomena may be explained by a gradual increase in bottom sediment silting, organic enrichment and pollution of the areas being studied. It was found that the degree of scallop shell bioerosion increased with the scallop's age. At present, In each age group, the shells of the scallops sampled from the muddy sand showed greater erosion than the shells of individuals collected from the sandy substrate.

• Tribology and Lubricants
• /
• v.3 no.2
• /
• pp.68-71
• /
• 1987

This paper deals with some thermal Characteristics of journal bearing such as the behaviour of the maximum bearing temperature, the lubricant's carry-over in the inlet region and so on. Temperatures of the bearing and the lubricants being supplied and discharged were measured along with shaft speed and bearing load. The results showed that with the increase of the Shaft speed, the maximum temperature rose at any shaft speed at a defferent rate of change defending on the flow regime of the lubricant film. And the lower eccentricity ratio is the more lubricant's carry-over occur. Additionally it was partially proved that the oil discharge temperature and the maximum temperature changed in quite different each other.