• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.4
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• pp.121-128
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• 2000

When RC beams are strengthening in flexure with steel plate, they have initial strain due to dead load. Strain of steel used in strengthening member is zero. The effect of strengthening in flexure at member changes in accordance with the quantity of initial strain. But in most cases, Quantity of reinforcement is determined without regard to the difference of initial strain when there are calculated the strengthening in flexure at beams. Such method is possible to suggest inadequate quantity of reinforcement. Thus, the object of the study is to suggest practical design equation and reinforcement proposal using comparison and analysis reinforcement efficiency about fexural strength in case with regard and without regard to the initial strain when Re beams are strengthening in flexure with steel plate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.153-162
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• 2001

This paper presents the fundamental study on rational manufacture of Ultra High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the UHS concrete(target compressive strength : over $1,000kgf/cm^2$) which is easily workable (target slump flow : $60{\pm}10cm$). The main variables are studied: 1) to find the optimum replacement ratio of mineral admixture. 2) to find a rational water-binder ratio and a proper binder content. 3) to find the method for reduction of slump loss. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume. We found that compressive strength of UHS concrete increases according to decreasing W/B ratio but in W/B ratio 18~20%, the difference is vague and the compressive strength does not necessarily increase according to increasing binder content over 700kg.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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• pp.193-203
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• 2002

The results of an experimental study on Saemangeum dredged sands are presented. Undrained triaxial compression tests were performed with there different initial relative densities, namely 18, 34, and 50%, intend to evaluate undrained Behavior. All undrained triaxial compression tests were performed under static loading conditions. Undrained triaxial compression tests were exhibited complete static liquefaction, zero effective confining pressure and zero stress difference at lower confining pressures. As confining pressures were increased, the effective stress paths indicated increasing resistance to static liquefaction by showing increasing dilatant tendencies. The fines and larger particles create a particle structure with high compressibility at lower confining pressure. The effect of increasing relative density was to increase the resistance of the sand against static liquefaction by making the sand more dilatant.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.95-105
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• 2009

In this study, we presented the periodic inspection method of the Certified Missile Round Concepts usuing M&S(Modeling and Simulation) techniques. Firstly, We drew up the scenario from the application concepts and the predicted dormant reliability Secondly, we performed the modeling for a simulation program based on the scenario. Lastly we embodied the simulation program. After comparing and examining the difference between the simulation results and the theoretical estimates, we present the best periodic inspection plan for achieving the probability of success.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.87-91
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• 2015

Eight minerals (Ca, Cu, Fe, K, Mg, Mn, Na and Zn) were determined in Schizandra chinensis fruits and their infusions in Seoul. The average mineral contents per Schizandra chinensis fruits (100 g) were K (966.08 mg), Mg (87.20 mg), Ca (15.19 mg), Mn (6.19 mg), Fe (3.99 mg), Zn (2.78 mg), Na (2.15 mg) and Cu (0.31 mg) respectively by Inductively Coupled Plasma-Mass Spectrometer. The quantity of K and Zn were found significantly higher in Korean fruits than the Chinese fruits (p < 0.05). The other 6 minerals did not reveal remarkable difference. In the case of processed Schizandra chinensis tea, it had K (217 mg), Mg (20.40 mg), Ca (7.16 mg), Na (2.95 mg), Mn (1.34 mg), Fe (0.95 mg), Zn (0.25 mg) and Cu (0.09 mg) per 100 g respectively. In extraction of Schizandra chinensis fruits, as it took a longer extraction time, and in a powder form rather than a raw form, it had a higher contents of minerals. When a powder type of Schizandra chinensis fruits was extracted for 24 hours at $25^{\circ}C$, the transfer rate appeared with Ca (36.27%), Mn (25.44%), K (22.43%), Zn (21.00%), Na (19.91%), Mg (19.55%) Cu (13.78%) and Fe (6.45%) respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.107-115
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• 2014

In this study, we examined the seismic isolation effects due to the difference between the center of mass of the building and the center of stiffness of isolation layer. Because the base isolation technique is a technique that is highly dependent on the performance of seismic isolation devices installed on the seismic isolation layer, we have to examine the horizontal stiffness of seismic isolation devices after making them. If difference between the design stiffness and the actual stiffness of the seismic isolation device occurred, a big problem may be generated in the upper members on the seismic isolation layer. The analytical results show that the more eccentricity increases, the more maximum response acceleration, story shear and the member forces of the upper part of the structure increases, and the damage is expected to be in excess. Therefore, it is recommended that if possible, isolation devices have to be designed to coincide the center of mass of the building with the center of stiffness of isolation layer. If not after making isolation devices, they need to be relocated to prevent the eccentricity.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.482-486
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• 2000

The purpose of the present study was first, to evaluate the relationship between composite surface conversion and surface discoloration, second, to know if there was difference in surface discoloration between celluloid-strip-finished composite surface and polished surface. In addition, the discoloration of composite surface was also evaluated with visual inspection or digital camera with high resolution monitor, Z100, Tetric Ceram, Spectrum, and Aelitfil were used. The composite surfaces were celluloid-strip finished (group 1), polished (group 2), celluloid-strip finished under nitrogen gas purging (group 3) or only light cured without finishing or polishing under nitrogen gas purging (group 4). The microhardness of each samples were also measured in each group. The samples of each group were also divided into 4 subgroup whether they were immediately placed in disclosing solution (0.2% Elythrosin, pH 7.0) (subgroup1), 1 day after light curing(subgroup 2), 3day after light curing(subgroup 3) or 7 day after light curing(subgroup 4). The computer controlled spectrophotometer was used to determine CIELAB coordinates ($L^*$, $a^*$, $b^*$). The amounts of color difference were compared. The results were as follows; 1. There was no difference in discoloration between celluloid strip finished composite surface and polished surface. 2. The samples discolored more when they were placed in disclosing solution immediately after polymerization than other groups. 3. When the samples were light cured under nitrogen gas purging and without polishing process, they discolored more than other groups even though they showed higher micro hardness. 4. With visual inspection or digital camera, only a limited information was available in detecting composite surface discoloration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.445-453
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• 2013

This paper was calculated the earthquake load using ELFP(Equivalent Lateral Force Procedure) and RSA(Response Spectrum Analysis) for PSC Box Girder representative bridges by the Phase of KTX designed by ELFP and verified the difference of these analyses. It have been modeled 3 dimensional FE model of 5 bridges using a commercial FEM program for the comparison of these analyses using a commercial FEM program and were compared the earthquake load. It has been to confirm the increase of the difference ELFP of RSA calculated to seismic ground acceleration according to the ground condition and natural period. It is mean that the necessity of seismic reinforcement due to the application of a larger of earthquake load than designed earthquake load form the seismic performance evaluation result according to the difference of calculated earthquake loads.

• The Journal of the Korea Contents Association
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• v.7 no.10
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• pp.302-310
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• 2007

This research, through an empirical analysis of the management of food materials in the super deluxe and deluxe hotels in Seoul, verified the difference, and established strategies according to the difference. According to the study, to enhance the level of the food material management, the introduction of scientific methods and system of the deluxe hotels has to be preceded, the training of special inspectors and the utilization of inspection methods needs improvement, and the purchasing contracts and effective purchasing methods have to be renewed. As for the storing management, the difference between hotel grades was low. The implication of this study as follows. First, to enhance the efficiency of man power operation, we have to introduce computer systems. Second, training based on the food materials purchasing manual has to be achieved. Third, we have to increase inspectors' specialty through the arrangement of man power rotation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.185-191
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• 2003

This paper presents the thermal problems of steel-concrete composite structure and the basic references in placing concrete into the structure. Based on the analytical investigation, application of the composite structure has the effect of highly decreasing the temperature difference between the center section and the surface section of the structure, though its application has little influence on the decrement of the maximum temperature under the same using material and placing temperature. Meanwhile, its application causes the section decrement of a concrete structure, and in the section which the decrement ratio is relatively large, the restraint action by a old concrete structure takes place highly tensile stresses over a tensile strength. And, the stress is concentrated on sharp edges of the steel-concrete boundary. Both restraint action and stress concentration considerably decrease the reduction effect of the temperature difference. Therefore, the prediction of thermal response and the reasonable steps are required through the simulation considering the factors and the sections related to those problems.