• Journal of the Korean Society of Safety
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• v.3 no.1
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• pp.21-29
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• 1988

Conventional pwm switching power supply have the disadvantage some aspects of size, light weight, noise and system stability. High frequency Series Resonant Converter (SRC), described in this paper, almost improve above disadvantages. We use the state plane technique as analysis method. This technique is powerful tool which can clearly analyze the peak stress of the state variables inside the converter, Here, we can define each operation mode from frequency ratio Fsn, switching frequency to resonant frequency, and we analyze the output performance in each operation mode. To verify the theoretical analysis, we compose the actual converter, and the experimental results are compared with analysis.

• Proceedings of the KIEE Conference
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• summer
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• pp.1260-1262
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• 2004

Direct Load Control(DLC) system is a load management program for stablization of electric power supply-demand. It is a series of acts limiting the demand of selected demand side at peak load or other time periods. Recently, power supply-demand instability due to dramatic increase in power usage such as summertime air-conditioning load has brought forecasts of decrease in power supply capability. Therefore heightening the load factor through systematic load management, in other words, Direct Load Control became necessary. By examining the composition and operation of the DLC system, this paper provides conceptional understanding of the DLC system and help in system research.

• Journal of the Korean Society of Visualization
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• v.17 no.1
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• pp.10-18
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• 2019

In this study, the temperature behavior of Pulsating Heat Pipe (PHP) according to the diameter change were studied by limiting the diameter change to only the evaporator. To investigate operation of PHP in various heat input, heat input power was increased from 10 to 120 W. The results show operation can be divided into 3 regimes by temperature behavior. Thermal resistance was increased before start-up and decreased with increasing heat input. At 110 W heat input, thermal conductivity of 2 mm PHP was 8 .times higher compare to thermal conductivity of copper. Further, to investigate details of temperature behavior in higher heat input, FFT analysis was conducted. Based on the results, when the deviation of peak frequency in each section is lowest, the thermal resistance has lowest value.

• Journal of Energy Engineering
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• v.28 no.2
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• pp.36-46
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• 2019

Through the application of ESS-based fusion products to the demonstration site of the urban distribution logistics facilities for designing the peak control and the substitution before the emergency generator operation by product application and the effective application method by the product application and the data analysis by overcoming the spatial limitation of ESS installation and distribution, And the expansion of distribution and logistics facilities.

• Nuclear Engineering and Technology
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• v.50 no.7
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• pp.1190-1197
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• 2018

Analysis of the GRSW-A model coupled into the FALCON code is extended by simulation of central void formation in fuel pellets due to high-temperature fuel restructuring. The extended calculation is verified against published, well-known experimental data. Good agreement with the data for a central void diameter in pellets of the rod irradiated in an Experimental Breeder Reactor is shown. The new calculation methodology is employed in comparative analysis of modern BWR fuel behavior under assumed high-power operation. The initial fuel porosity is shown to have a major effect on the predicted central void diameter during the operation in question. Discernible effects of a central void on peak fuel temperature and Pellet-Cladding Mechanical Interaction (PCMI) during a simulated power ramp are shown. A mitigating effect on PCMI is largely attributed to the additional free volume in the pellets into which the fuel can creep due to internal compressive stresses during a power ramp.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.780-788
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• 1986

1.3\ulcorner GaInAsP BH(Buried Heterostructure) lasers were fabricated on the p-InP substrate. Two step chemical etching processes and melt-back etching technique during 2nd epitaxy were used for BH active layer. BH laser had the threshold current, Ith, of 72mA(23\ulcorner), peak wavelength of 1.2937\ulcorner, nd of 10-20%, and To of 85K. They operated in single mode under pulse condition up to 1.4 Ith. CW(DC) operation was successfully performed at room temperature.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.66-70
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• 1998

Background and Objectives : The managements of unilateral vocal cord palsy include type Ⅰ thyroplasty and arytenoid adduction. One type operation has been shown no satisfactory effect. We evaluated preoperative and postoperative speech of unilateral vocal cord palsy patients who received combined operation of type Ⅰ thyroplasty and arytenoid adduction to help for the management plan of unilateral vocal cord palsy patients. Materials and Methods : We reviewed the postoperative results and complication of 17 surgically treated patients of unilateral vocal cord palsy at Severance hospital from Nov. 1996 to Dec. 1997 retrospectively. They were received combined operation of type Ⅰ thyroplasty and arytenoid adduction. Their pre and post-operative speech were analyzed with MDVP(Multi-Dimension-Voice analysis Program) of CSL(Computerized Speech Lab). Results : After the operation, MPT(Maximal Phonation Time) was increased and MFR(Mean Flow Rate) was decreased in all patients. NHR(Noise to Harmonic Ratio) and VTI(Voice Turbulence Index) were decreased : liner, RAP(Relative Average Perturbation Quotient), PPQ(Pitch Period Perturbation Quotient), sPPQ(smoothed Pitch Period Perturbation Quotient), vFo(fundamental frequency Variation) were decreased : Shimmer, APQ(Amplitude Perturbation Quotient), sAPQ(Smoothed Amplitude Perturbation Qoutient), vAm(Peak Amplitude Variation) were decreased in all the patients. Conclusions : In unilateral vocal cord pals), combined operation of type Ⅰ thyroplasty and arytenoid adduction could obtain satisfactory postoperative voice. MDVP has many parameters and good method for evaluation of voice surgery.

• Journal of Nutrition and Health
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• v.32 no.2
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• pp.150-157
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• 1999

This study explored the effects of dietary calcium levels and/or ovariectomy on bone formation, bone composition and calcium metabolism using female Sprague-Dawley weanling rats(mean body weight$\pm$SEM : 232.3$\pm$6.7g) as a model. Rats received high(1.5%) calcium diets for eight weeks during the growth period and were randomly assigned to ovariectomy and sham groups. The two groups were than each randomly divided into three sub-groups and fed 0.1%, 0.5% and 1.5% calcium diets for eight weeks after operation. The results indicate that body weight gain was higher in ovariectomy groups than sham groups regardless of dietary calcium levels and food intakes. Serum Ca concentration was decreased in low Ca groups after operation and serum P concentration increased in ovariectomy groups. Serum Ca concentration was decreased in low Ca groups after operation and serum P concentration increased in ovariectomy groups. Serum alkaline phosphatase activity was increased in ovariectomy groups and was not influenced by dietary calcium levels after operation. Urinary hydroxyproline decreased in high Ca intake groups regardless of whether rats had received an ovariectomy or not. The weight, length and breaking force of the femur were not significantly different in all groups. Ash, calcium, phosphate and magnesium contents in the femur and lumbar were not significantly different regardless of ovariectomy operation and dietary calcium levels. But high/normal calcium intake after ovariectomy and sham operation increased the weight and calcium content in bone. Therefore, high calcium intake influenced the formation of peak bone mass during the growth period and calcium levels and calcium levels and calcium levels continued to influence bone growth and composition after ovariectomy.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.197.2-197.2
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• 2010

The study on the operation characteristics of solar space and water heating system with ground source heat pump (GSHP) as a back-up device was carried out. This system, called solar thermal and geothermal hybrid system (ST/G), was installed at Zero Energy Solar House II (KIER ZeSH-II) in Korea Institute of Energy Research. This ST/G hybrid system was developed to supply all thermal load in a house by renewable energy. The purpose of this study is to find out that this system is optimized and operated normally for the heating load of ZeSH-II. Experiment was continued for seven months, from October to April. The analysis was conducted as followings ; - the contribution of solar thermal system. - the appropriateness of GSHP as a back-up device. - the performance of solar thermal and ground source heat pump system respectively. - the adaptation of thermal peak load - the operation characteristics of hybrid system under different weather conditions. Finally the complementary measures for the system simplification was referred for the commercialization of this hybrid system.

• Tunnel and Underground Space
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• v.7 no.2
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• pp.116-129
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• 1997

The objective of this study is to predict the minimization effect of the noise and vibration during the construction and the train operation regarding to the design modification of the Taegu Subway Line No. 1. It was suggested optimal control blasting methods to reduce the causing vibration Nuance to the resident in City Taegu and also proposed the better governing method to decrease the environmental hazard to the near buildings and residents during the train operation. When the high-density gaseous reaction of explosion products exerts a high pressure in motion outward, a dynamic stress field will be created in the surrounding buildings. Therefore, in the region close to the charge, permanent damage begins to occur at a great critical level of partial velocity, that is difficult from different structure as working conditions. It is reliable to predict that the damages could be reduced if we know the peak velocity and the exact reasons through the conducting of detail studies of structural analysis of the related buildings with the optimal blasting designs. A blasting technique should be deemed to take advantage of the reduction of damage of the surrounding rocks and structures to improve the in-city blasting. This is a typical in-city blasting operation where success depends on closely controlling the ground vibrations in case of better designed blasting methods. There are techniques that can be applied to prevent large vibrations from damaging the important buildings through the Route Modification of the Taegu Subway Line No. 1.