• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.581-581
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• 2018

• Journal of IKEEE
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• v.20 no.1
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• pp.61-67
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• 2016

In this paper, a hardware design method is proposed for high speed high precision neutron radiation measurements. Our system is fabricated to use a high performance A/D Converter for digital data conversion of high precision and high speed analog signals. Using a neutron sensor, incident neutron radiation particles are detected; a precision microcurrent measurement module is also included: this module allows for more precise and rapid neutron radiation measurement design. The high speed high precision neutron measurement hardware system is composed of the neutron sensor, variable high voltage generator, microcurrent precision measurement component, embedded system, and display screen. The neutron sensor detects neutron radiation using high density polyethylene. The variable high voltage generator functions as a 0 ~ 2KV variable high voltage generator that is robust against heat and noise; this generator allows the neutron sensor to perform normally. The microcurrent precision measurement component employs a high performance A/D Converter to precisely and swiftly measure the high precision high speed microcurrent signal from the neutron sensor and to convert this analog signal into a digital one. The embedded system component performs multiple functions including neutron radiation measurement for high speed high precision neutron measurements, variable high voltage generator control, wired and wireless communications control, and data recording. Experiments using the proposed high speed high precision neutron measurement hardware shows that the hardware exhibits superior performance compared to that of conventional equipment with regard to measurement uncertainty, neutron measurement rate, accuracy, and neutron measurement range.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.286-293
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• 2004

This paper presents the result of a study on the starter control for a turbo generator. Because a starter in gear box type turbo-generator system is composed of gearbox and brush DC motor, it should be replaced with High Speed Generator(HSG)) in HSG type Turbo-generator. There-ore, it is necessary to design a new starting algorithm and starter. In gearbox type system, brush DC motor is rotated to the designed speed using low voltage-high current battery power. After brush DC motor speed is increased to several times by gearbox, gas turbine engine can be rotated to designed starting speed. If we implement a starter with High Speed Generator(HSG), it is necessary to drive high-speed generator to high-speed motor. High-speed generator with permanent magnet on rotor has a low leakage inductance fur driving high-speed rotation, and it is necessary high DC link voltage for inverter when High-speed generator is driven to high speed. This paper presents result of development of the boost converter for converting high voltage DC from low battery voltage and design of the inverter for controlling a high frequency current to be injected to motor winding. Also, we show performance of the designed starter by driving the turbo generator.

• Clinical and Experimental Pediatrics
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• v.57 no.2
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• pp.79-84
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• 2014

Purpose: Overweight can be defined by the body mass index (BMI) and is likely associated with an increased cardiovascular disease risk. However, waist circumference (WC), a central adiposity index, may be a better indicator of cardiovascular disease risk. Studies comparing the effects of BMI and WC on cardiovascular risk factors, such as high blood pressure (BP), are rare in adolescents. Methods: We analyzed the correlations of BMI and WC with BP in 3,363 Korean adolescents (aged 10-19 years), using data from the Korean National Health and Nutrition Examination Surveys (2009-2011). Results: Systolic BP (SBP) in both sexes and diastolic BP (DBP) in boys were higher in the high BMI (>85th percentile) and high WC (>90th percentile) groups. High BMI and high WC were positively correlated with high SBP (>90th percentile) in both sexes, and high DBP (>90th percentile), in boys. BMI maintained its positive associations with SBP, DBP, high SBP, and high DBP in the normal weight ($BMI{\leq}85th$ percentile) and overweight (BMI>85th percentile) groups in both boys and girls, as well as in all subjects of both sexes, even after adjustment for WC. However, WC did not correlate with SBP, DBP, high SBP, or high DBP after adjustment for BMI in any group in either sex. Conclusion: In Korean adolescents, BMI correlated better with BP and high BP levels than WC. Further, BMI was positively associated with BP and high BP in the normal weight group as well as in the overweight group.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.2
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• pp.393-404
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• 2013

In order to improve the employment rate of graduates in maritime and fisheries high schools, we investigated the employment situations of the those graduates for the last 8 years. The results were as follows, The ratio of graduates in maritime and fisheries high schools to total graduates of on-board departments are 69.1% and 30.9% respectively. The on-board employment rate of maritime high schools and fisheries high schools graduates are 63.2% and 26.7% respectively. Nearly all of the maritime high schools students were employed to merchant ship and fisheries high schools students were employed to merchant ship 77.2% and only 22.8% of them got a job on fisheries ship. The ratio of getting a job in maritime high schools to ocean-going ship was 76.7%, that was the highest ratio and the ratio of fisheries high schools got a job to ocean-going ship was 55.1%. The on-board career of maritime high schools graduates was 1~5 years, which took 86.4% of all careers and that of fisheries high schools was less than 1 year, which took 60.0% of all careers. We should make the various efforts to improve the employment rate of getting job to fisheries ship in the fisheries high school graduates.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.215-221
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• 2014

Ultra-high strength concrete and high tensile steel are becoming very attractive materials for high-rise buildings because of the need to reduce member size and structural self-weight. However, limited test data and design guidelines are available to support the applications of high strength materials for building constructions. This paper presents significant findings from comprehensive experimental investigations on the behaviour of tubular columns in-filled with ultra-high strength concrete at ambient and elevated temperatures. A series of tests was conducted to investigate the basic mechanical properties of the high strength materials, and structural behaviour of stub columns under concentric compression, beams under moment and slender beam-columns under concentric and eccentric compression. High tensile steel with yield strength up to 780 MPa and ultra-high strength concrete with compressive cylinder strength up to 180 MPa were used to construct the test specimens. The test results were compared with the predictions using a modified Eurocode 4 approach. In addition, more than 2000 test data samples collected from literature on concrete filled steel tubes with normal and high strength materials were also analysed to formulate the design guide for implementation in practice.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.265-269
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• 2008

Output voltage value of AC high voltage source has usually been obtained by measuring the low arm voltage of high voltage divider or the secondary voltage of high voltage transformer. In this study, we have fabricated the AC 400 kV high voltage divider using high voltage electrode and electric field measurement sensor. The dividing ratio of the fabricated 400 kV high voltage divider was evaluated using reference 400 kV capacitive divider. The dividing ratio of 400 kV high voltage divider is found to be 12,322 and has the good linearity within 0.63 % against AC high voltage up to 400 kV. Therefore, the developed 400 kV high voltage divider could evaluate 400 kV high voltage supply and voltage divider used in industry.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1409-1418
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• 2001

Two trials were carried out during two different grazing seasons to evaluate effect of grass silage supplementation, when amount of pasture is limited on dry matter intake (DMI), milk production, and gross energetic efficiency (GEE) of grazed lactating cows on a high forage-based diet. Fifty-one Holstein cows were randomly assigned to one of two dietary treatments: high pasture group or high silage group. In the spring flush, pasture and silage DMI, milk yield, milk fat percentage, and GEE were not different between the dietary groups. After the spring flush, pasture and silage DMI were higher for the high silage group than for the high pasture group. After the spring flush, although these were the higher total DMI of the high silage group than the high pasture group, milk yield was significantly (p<0.05) higher for the high pasture group than the high silage group. Milk fat percentage tended to be higher for the high silage group than the high pasture group. The GEE was significantly (p<0.05) higher for the high pasture group than the high silage group during after the spring flush. This study indicated that supplementation of grass silage, especially after the spring flush, can have a significant effect of increasing of forage intake and maintenance of the milk fat percentage; but not increase milk yield and GEE.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.105-111
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• 2012

High speed machining is the core technology that influences the performance of machine tools, and the high speed motor spindle is widely used for the high speed machine tools. The important problem in high speed spindle is to minimize the thermal effect by motor and bearing and frequency effect. This paper presents the thermal characteristic analysis and frequency experiment for a high speed spindle considering the flow rate of cooling oil. A high speed spindle is composed of angular contact ceramic ball bearings, high speed built-in motor, oil cooling jacket and so on. The thermal analyses of high speed spindle need to minimize the thermal effect and maximize the cooling effect and they are carried out under the various cooling conditions. Heat generations of the bearing and the high speed motor are estimated from the theoretical and experimental data. To find out the characteristic of vibration, the high speed spindle is excited in operational range. This result can be applied to the design and manufacture of a high speed tapping spindle.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.71-74
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• 2005

The viscosity of high-flowability paste is very high compared to normal concrete for the low water-binder ratio(W/B). Therefore, high-flowability concrete is positively necessary to high-range water reducing agent. High-Flowability paste can make much higher fluidity with no occurrence of segregation, by its higher viscosity and lower yield value than normal concrete. The flowability of high-flowability paste must be evaluated not only by convention consistency test such as slump test but also by the base of the rheological properties of the fresh concrete. The purpose of this study is to analyze the fluidity of high-flowability paste according to the addition ratio of the Melamine Sulphonate high-range water reducing agent.; high-flowability paste is considered as Bingham plastic fluid with the rheology parameters of the plaste viscosity and yield value.