• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.100-107
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• 1994

A statistical methodology is developed for calculating the nuclear fuel pod internal pressure of Korean PWR fuel in order to reduce over-conservatism of the current KAERI deterministic methodology. The developed statistical methodology employs the response surface method and Monte Carlo calculation. The simple regression equation for the rod internal pressure is derived by taking into account the various fuel fabrication-related and fuel performance model-related parameters. The validity of the regression equation is examined by the F-test, $R^2$-method and Cp-test The internal pressure predicted by the regression equation is in good agreement with that calculated by he computer code using the KAERI deterministic methodology. The distribution of the internal pressure from the Monte Carlo calculation is found to be normal. Comparison of the 95/95 rod internal pressure predicted by the developed statistical methodology with the maximum rod internal pressure by the deterministic methodology shows that the developed statistical methodology reduces significantly over-conservatism of the deterministic methodology.

• Journal of the Korea Concrete Institute
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• v.19 no.3
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• pp.351-358
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• 2007

Unlike external bonded steel plate or carbon fiber, the external unbonded strengthening using hi-strength bar has some advantages in speed and simplicity of installation. It is not required surface preparations and not affected by environmental conditions. A set of nine laboratory tests on RC beams strengthened using the hi-tension bars are reported. Anchoring pin developed in former research is installed at the end of beam to connect the hish-tension bar to RC beam. The test results strengthened by hi-tension bars are compared with those of non-strengthened specimens. The main test parameters are the cross-sectional area of the high-tension bar, distance of stirrups and condition of supports. Test results show that the beams reinforced are superior to reference specimens, especially for the strength and deformation capacity. Also, shear resisting effect of hi-strength bar can be confirmed in the specimens which have lack of stirrups.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.10a
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• pp.198-202
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• 2009

Split Hopkinson pressure bar(SHPB) is used to obtain compressive stress-strain data and deformation characteristics of brittle materials such as rock and concrete. SHPB demands both dynamic stress equilibrium condition and nearly constant strain rate before the failure of the specimen. Pulse shape technique, which places a thin metal disk between launched impact bar and incident bar, should be adopted to satisfy both conditions. In this study, metallic disks with various shapes were used to control the incident impact wave. The results show that the peak value of stress and the length of waves increased with decreasing thickness and diameter of the pulse shaper. In order to investigate shape and strain rate-dependency of the pulse shapers, dynamic compressive stress-strain curves were obtained and analyzed.

• Nuclear Engineering and Technology
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• v.28 no.2
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• pp.162-174
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• 1996

The local hydraulic characteristics in a single phase flow of a 6$\times$6 rod bundle with neighboring different spacer grids were measured by using a LDV(Laser Doppler Velocimeter) system. 6$\times$6 rod bundle is formed by two 3$\times$6 rod bundles with different spacer grids. The objective of this study in a rod bundle is to investigate the thermal-hydraulic interactions between different spacer grids with different configurations and resistance. By using a LDV system, the velocity and turbulent intensity in axial and horizontal directions ore measured. Pressure drop measurements ore also performed to evaluate the loss coefficient for the spacer grid and the friction factor for rod bundles. Implications concerning thermal mining due to spacer grids were investigated based on the hydraulic test results. Swirl factor, which is assumed as a qualitative criteria for DNB(departure from nucleate boiling), was defined and estimated from the horizontal velocity result.

• The Journal of the Petrological Society of Korea
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• v.23 no.4
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• pp.325-336
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• 2014

Even though Mesozoic Mudeungsan tuff, located within Neungju Basin, has been named several rock names, it should be named as Mudeungsan tuff due to several evidences, such as fiamme, welded texture and rock fragments in the Mudeungsan tuff. Volcanic eruption boundary between the Cheonwangbong and Anyangsan areas is not clear, but petrochemical and mineral chemical evidences with different ages indicate clear petrological boundary between Cheonwangbong and Anyangsan. The Mudeungsan tuffs from Cheonwangbong and Anyangsan is welded crystal tuff with dacitic composition and were generated from cogenetic calc-alkaline magma in the volcanic arc environment. Geochemical events indicate that magma beneath Cheonwangbong was seems to have been evolved from the magma beneath Anyangsan due to fractional crystallization dominated by plagioclase.

• Korean journal of applied entomology
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• v.30 no.3
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• pp.180-186
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• 1991

This study was carried out to acquire some basic biochemical informations on the granulosis virus(GV) of Pieris rapae and Pieris brassicae. The capsule protein was composed of a single polypeptide with a molecular weight of 30,000 dalton for P. rapae GV and 31,000 dalton for P. brassicae GV. The major amino acids of capsule protein were glutamic acid, aspartic acid and lysine. When the capsule protein was partially digested with trypsin, chymotrypsin, papain or Staphylococcus aureus V8 protease, the digested products of the two viruses showed no difference in electrophoretic mobility. The patterns of the polypeptides of the two virus particle on SOS-polyacrylamide gel showed a little difference in high molecular weight region(over MW 100 kd).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.791-799
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• 2016

To ensure the reliability and safety of various mechanical systems in accordance with their high-speed usage, it is necessary to evaluate the dynamic deformation behavior of structural materials under impact load. However, it is not easy to understand the dynamic deformation behavior of the structural materials using experimental methods in the high strain-rate range exceeding $10^4\;s^{-1}$. In this study, the Taylor bar impact test was conducted to investigate the dynamic deformation behavior of metallic materials in the high strain-rate region, using a high-speed photography system. Numerical analysis of the Taylor bar impact test was performed using AUTODYN S/W. The results of the analysis were compared with the experimental results, and the material behavior in the high strain-rate region was discussed.

• The Journal of the Petrological Society of Korea
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• v.18 no.3
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• pp.181-194
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• 2009

The Cheongryangsan Formation was reported to stratigraphically overlie the Gasongdong Formation and underlie the Dogyedong Formation in the northern part of the Yeongyang subbasin, and be divided into the lower Cheongryangsan Member and the Osipbong Member. But the members have more widely called as the Cheongryangsan Conglomerate and the Osipbong Basalt, because the latter have initially meant that thin basalt flows several times intercalate sedimentary rocks in the northern part but later must consider that they have a very dominant volume in the eastern one. Both formations are based on classifying the stratigraphy and play a role of an excellent key bed for stratigraphic correlation between local spaces in the subbasin dominant absolutely for reddish beds. Both formations play a role of excellent key bed in the northern and northwestern areas of the subbasin; the Osipbong Basalt, the midwestern, eastern and southern ones; the Cheongryangsan Conglomerate, the southeastern one.

• Membrane Journal
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• v.19 no.4
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• pp.285-290
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• 2009

The permeation experiments were carried out for the nominal pore size $0.1\;{\mu}m$ and 5 mm inner diameter microfiltration tubular membrane equipped with self-designed discharging rod in order to determine the effect of fouling reduction. Dioctyl tinoxide (DOTO) latex particle was used to prepare up to 0.5 wt% concentration of feed solution, and the experiments were operated within 1.6 bar. The permeation flux effect on the discharged rod was measured as a result of flux comparison between the cases of equipped and non-equipped discharge rod modules for every experiment. The permeation flux for the case using the discharged rod was enhanced to 20% at 1.6 bar operating pressure. The improvement on permeation flux for using the discharged rod was greater as the concentration of feed increased, and reached up to 43% under 0.5 wt% concentration of feed solution.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.1
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• pp.63-70
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• 1983

Recently, many studies for developing the underwater welding techniques have been carried out in the advanced countries as a manufacturing process and a repairing method according as a great deal of interest in development for various marine industrial fields has been gradually increased. But no study on such underwater welding is available at present in our country. In this study, underwater welding was carried out for welding of domestic structural steel plates (SM41A) of 10 mm thickness, using six types of domestic coated arc welding electrodes on a self-made gravity type underwater welding device, resulting in investigation for the underwater weldability of the domestic structural steel plates as well as for the underwater welding properties and practicability of the domestic welding electrodes.