• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.9 no.1
• /
• pp.40-47
• /
• 2013

The capacity factor of nuclear power plant in Korea is the highest level in the world. However, the integrity assessment of nuclear power plant is depended on foreign country. Especially, most eddy current testing systems for inspecting steam generators in nuclear power plant are currently imported from USA, Canada, and so on. Therefore, the eddy current testing system can react more active and adaptive from economic and managerial standpoint for actual nuclear power plants in Korea is required. In this paper, an eddy current testing system for inspecting steam generators in nuclear power plants is introduced. Frequency generator, analog circuit, analog digital converter circuit, and digital control circuit are composed in eddy current testing system. A benchmarking of acquisition system and acquisition software, eddynet 11i made by Zetec, and modifications are carried out based on the test environment of Korea nuclear power plants. Finally, all eddy current apparatus are integrated to inspect steam generator tubes in nuclear power plants.

• Herbal Formula Science
• /
• v.15 no.2
• /
• pp.89-98
• /
• 2007

Kyungisan (KGS) has been used in oriental medicine for many centuries as a therapeutic agent for treatment of stroke caused by deficiency of qi(氣虛). This study was performed to evaluate effects of KGS extract on the regional cerebral blood flow(rCBF) and mean arterial blood pressure(MABP) in rats. The result of this study were as follow ; 1. KGS significantly increased rCBF irrelevant to MABP in normal rats, 2. To prescribe KGS after pretreatment with indomethacin(IDN) decreased rCBF as compared with control group to administered only KGS in normal rats. But the change of MABP is not significantly as compared with control group. 3. To prescribe KGS after pretreatment with methylen blue( MTB) decreased MABP and rCBF as compared with control group to administered only KGS in normal rats. Especially, it significantly decreased rCBF. These results suggest that KGS increase rCBF by enlargement diameter of pial artery in brain. The active mechanism of KGS is related with prostaglandin activated by cyclooxygenase. So, I suggest that KGS has an anti-ischemic effect through the improvement of cerebral blood flow and can be used for stroke.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.12 no.1
• /
• pp.78-84
• /
• 2016

The FHX (Forced-draft sodium-to-air Heat Exchanger) employed in the ADHRS (active decay heat removal system) is a shell-and-tube type counter-current flow heat exchanger with M-shape finned-tube arrangement. Liquid sodium flows inside the heat transfer tubes and atmospheric air flows over the finned tubes. The unit is placed in the upper region of the reactor building and has function of dumping the system heat load into the final heat sink, i.e., the atmosphere. Heat is transmitted from the primary cold sodium pool into the ADHRS sodium loop via DHX (decay heat exchanger), and a direct heat exchange occurs between the tube-side sodium and the shell-side air through the FHX tube wall. This paper describes the DHRS and the structural design of the FHX.

• Journal of Nutrition and Health
• /
• v.30 no.3
• /
• pp.277-285
• /
• 1997

The purpose of this study was to investigate the relationship among nutrient intake, life style, and serum lipids level in 108 healthy middle-aged men in Taegu. A convenient method was to assess nutritional intake. Anthropometric measuement of body weight and hight were measured and average energy expenditure was calculated. The mean body mass index(BMI) was 22.8$\pm$2.4 and it was in the middle of the mean BMI of Korean men. Obesity rate of study subject were 13.2%. Daily energy intake was not sufficient as 88.4% of recommended dietary allowances and the energy percentage of carboydrate, fat protein was 65 : 21 : 14. Mean intake of vitamin A, B1, C and Ca were lower than RDA. There was a highly significant negative correlation between the systolic blood pressure and calcium intake(r=-0.28, p<0.05). Smokers showed significantly higher blood glucose than non-smokers. Skipping meals and uneven diurnal distribution(no breakfast and large evening meals) are associated with high triglyceride level in this population. There was a highly significant correlation between body weight and plasma lipids. Energy expenditure was negatively correlated with plasma triglyceride level. Especially, atherogenic index was significantly lower in job-time physically active worker than that in sedentary worker. Above data provides valuable imformation to the community for program planning as well as to health providers who work individual male adults to meet their nutrition needs and to control blood lipids.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.7
• /
• pp.647-651
• /
• 2005

We studied the external pressure-stable advanced frnge field switching (FFS) pixel design with 3 slit sructue. In this mode, a patterned pixel slit is partitioned into 3 areas, namely, two edges and a center, where the edge slit angle is larger than the center slit angle. Thus the reverse twist region in the pixel edge is reduced comparing to the conventional FFS mode so that the LC dynamics in this region becomes very stable. And also, when the external pressure is applied to the panel at the high voltage, the disclination lines (DLs) were barely intruded into active area. Therefore, the structure is use for the pen based system such as the tablet personal computer (PC), personal digital asistant (PDA).

• Journal of Mechanical Science and Technology
• /
• v.17 no.9
• /
• pp.1358-1370
• /
• 2003

The effects of anode, cathode, and cooling channels for a Proton Exchange Membrane Fuel Cell (PEMFC) on flow fields have been investigated numerically. Continuous open-faced fluid flow channels formed in the surface of the bipolar plates traverse the central area of the plate surface in a plurality of passes such as a serpentine manner. The pressure distributions and velocity profiles of the hydrogen, air and water channels on bipolar plates of the PEMFC are analyzed using a two-dimensional simulation. The conservation equations of mass, momentum, and energy in the three-dimensional flow solver are modified to include electro-chemical characteristics of the fuel cell. In our three-dimensional numerical simulations, the operation of electro-chemical in Membrane Electrolyte Assembly (MEA) is assumed to be steady-state, involving multi-species. Supplied gases are consumed by chemical reaction. The distributions of oxygen and hydrogen concentration with constant humidity are calculated. The concentration of hydrogen is the highest at the center region of the active area, while the concentration of oxygen is the highest at the inlet region. The flow and thermal profiles are evaluated to determine the flow patterns of gas supplied and cooling plates for an optimal fuel cell stack design.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.679-682
• /
• 2002

Energy dissipations in a general PHE flow are the compounded effects of the piled corrugate geometries and its wall pressure and temperature distributions. In addition, although the exchangers are substantial pieces of engineering equipment, they are composed of a very large number of nominally identical and small geometrical elements. In the present numerical study, the three-dimensionally complicated energy dissipation fields and those wall-shape-induced flow destabilization are investigated in the cross-corrugated passages, which result in high energy transports with comparatively low pressure drop. We revealed the critical conditions as $Re=157.3 for the wall-shape-induced flow destabilization in a general PHE element by initial value method, or shooting method, and compare its value to that of analytical solution of plane Poiseille flow, two-dimensional grooved flow and so on. We also observed the detailed variation of flow field and energy transportation with changes in time and flow variables such as Reynolds number. Lastly, we considered the flow natural frequency, or Strouhal number, with variation of hydrodynamic conditions for the best use of active control, such as forced mass flow rate pulsative flow, to enhance energy transportation.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.147-151
• /
• 2007

A serpentine channel geometry often used in a polymer electrolyte membrane fuel cell has a strong pressure gradient between adjacent channels in specific regions. The pressure gradient helps some amount of reactant gas penetrate through a gas diffusion layer(GDL). As a result, the overall serpentine flow structure is slightly different from intention of a designer. The purpose of this paper is to examine the effect of serpentine flow structure on current density distribution. By using a commercial code, STAR-CD, a numerical simulation is performed to analyze the fuel cell with relatively high aspect ratio active area. To increase the accuracy of the numerical simulation, GDL permeabilities are measured with various compression conditions. Three-dimensional flow field and current density distribution are calculated. For the verification of the numerical simulation results, water condensation process in the cathode channel is observed through a transparent bipolar plate. The result of this study shows that the region of relatively low current density corresponds to that of dropwise condensation in cathode channels.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.3
• /
• pp.313-318
• /
• 2001

To establish nondestructive test method for aerospace composite materials, various composite specimens were tested and analyzed using acoutic emission. The hit rate of acoustic emission closely was rotated with crack initiation and propagation. This report also presents defection capability of crack initiation pressure, initial crack active location, and crack propagation using acoustic emission.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.9
• /
• pp.1369-1373
• /
• 2003

ACE (Angiotensin-I converting enzyme) inhibitory peptides derived from foods are thought to suppress high blood pressure by inhibiting ACE. We tried to make efficient production of the ACE inhibitory hydrolysate from egg albumen. A hydrolysate digested by neutrase presented the highest ACE inhibitory activity ($IC_50\;value=256.35{\mu}g/ml$) and the proper proteolysis was occurred by 1.0% enzyme addition and 4 h incubation at $47^{\circ}C$. Antihypertensive effect of neutrase hydrolysate was investigated in spontaneously hypertensive rats (SHR, n=5). Systolic blood pressure (SBP) was decrease by 6.88% (-14.14 mmHg, p<0.05) at 3 h after oral administration of 300 mg/kg body weight, and by 13.33% (-27.72 mmHg, p<0.05) by emulsified hydrolysate. These results showed that it is very effective to utilize egg albumen as a protein source for the production of ACE inhibitory peptides. However, further studies are required to investigate the methods to increase recovery yield and the isolation of active peptide is necessary for determining its sequence responsible for ACE inhibitory activity.