• Korean Journal of Materials Research
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• v.19 no.11
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• pp.569-575
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• 2009

In this study, the effects of silver treatment and activation on the physical and chemical properties of spherical activated carbon (SAC) were studied. The textural properties of SAC were characterized by BET surface area, XRD, SEM, iodine adsorption, strength intensity, pressure drop and antibacterial effects. BET surface areas of SACs decreased with an increase of the amount of PR before and after activation, and the BET surface areas of SACs were found to be about 2-3 times the size of those before activation. The XRD patterns showed their existing state as stable Ag crystals and carbon structure. The Ag particles are seaweedlike and uniform, being approximately 5-10 μm in size deposited on the surface of activated carbon. All of the samples had much more iodine adsorption capability after activation than before activation. The strength values of SACs increased with an increase of the amount of PR, and there was a smaller drop in the strength values of SACs with silver treatment than with non-silver treatment after activation. The Ag-SAC composites showed strong antibacterial activity against Escherichia coli (E. Coli).

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.1 s.47
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• pp.33-39
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• 2006

Parameters including the seismic sources and the elastic wave propagation characteristics were analysed using the observed ground motions from 3 Kyoungju region earthquakes. The Levenberg-Marquardt algorithm was applied to invert all the variables non-linearly and simultaneously with S wave energy In frequency domain. Average stress drop of 3 events and local attenuation parameter ${\kappa}$ were estimated to about 48-bar and 0.0312 respectively. Regional attenuation parameter, Qo and ${\eta}$, were also estimated to be about 417 and 0.83. ${\kappa}$ values are much higher than that of EUS, even though smaller than that of WUS. All these values resultant from this study show that there are differences in some parameters of other studios due to differences in the governing equation. of acceleration motions

• Journal of the Korean Society of Physical Medicine
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• v.17 no.2
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• pp.1-10
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• 2022

PURPOSE: This study examined the effects of the low dye taping technique on the static and dynamic balancing ability and navicular bone drop when the low dye taping technique was divided into elastic and non-elastic taping. METHODS: The subjects of the study were 31 volunteers without musculoskeletal disorders. The length (L) and anterior (A), posteromedial, and posterolateral values of the arch in the NO (normal eyes open), NC (normal eyes closed), PO (pillow with eyes open), and PC (pillow with close eyes closed) states were evaluated when barefoot and when Kinesio tape and non-elastic tape were applied. The measurements were analyzed using repeated ANOVA and an independent t-test. Post hoc tests were performed using a Fisher's LSD. RESULTS: A significant difference was found in the arch L and A values using a foot scanner (p < .05). In addition, there was a significant difference in dynamic balance in the three directions (p < .05), and no difference was found in the case of static balance. As a result, non-elastic tape application helps improve the dynamic balance ability and arch of the foot. CONCLUSION: The non-elastic tape technique is helpful for the foot arch function, and there is no difference in the static balance ability between Kinesio tape and non-elastic tape. Nevertheless, non-elastic tape is more helpful for the dynamic balance ability than Kinesio taping.

• Journal of the Korea Fashion and Costume Design Association
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• v.25 no.4
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• pp.147-161
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• 2023

This study used 3D anthropometric data from the 8th Size Korea to type and analyze whole body shapes of obese women in their 20s and 30s, and constructed dimensional data for human body items needed to create a 3D human body model for each type. The data analysis used data from 148 obese women in their 20s and 30s, and a total of 48 index values, drop values, and angle items were subjected to factor analysis and one-way variance analysis to categorize body types and verify significant differences by type. As a result of the factor analysis, 12 factors were extracted and divided into 4 body types. Type 1 is a 'standard type with a curved torso with balanced upper and lower body lengths', Type 2 is a 'bending forward type with a short, thick lower body, and an uncurved torso', Type 3 is a 'lean back type with a long and thin lower body and an H-shape torso', Type 4 is a 'sway back type with a long and thick lower body and abdominal obesity'. The representative body type of obese women in their 20s and 30s was identified as Type 1. The constructed body shape information will be used as basic data for future 3D human body modeling.

• Atmosphere
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• v.22 no.1
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• pp.73-85
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• 2012

The collision efficiency data for collision between graupel or hail particles and cloud drops that take into account the differences of particle density are applied to the Takahashi cloud model. The original setting assumes that graupel or hail collision efficiency is the same as that of the cloud drops of the same volume. The Takahashi cloud model is run with the new collision efficiency data and the results are compared with those with the original. As an initial condition, a thermodynamic profile that can initiate strong convection is provided. Three different CCN concentration values and therefore three initial cloud drop spectra are prescribed that represent maritime (CCN concentration = 300 $cm^{-3}$), continental (1000 $cm^{-3}$) and extreme continental (5000 $cm^{-3}$) air masses to examine the aerosol effects on cloud and precipitation development. Increase of CCN concentration causes cloud drop sizes to decrease and cloud drop concentrations to increase. However, the concentration of ice particles decreases with the increase of CCN concentration because small drops are difficult to freeze. These general trends are well captured by both model runs (one with the new collision efficiency data and the other with the original) but there are significant differences: with the new data, the development of cloud and raindrop formation are delayed by (1) decrease of ice collision efficiency, (2) decrease of latent heat from riming process and (3) decrease of ice crystals generated by ice multiplication. These results indicate that the model run with the original collision efficiency data overestimates precipitation rates.

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.3
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• pp.107-120
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• 2011

The increased availability of store brand suppliers now provides retailers with opportunities to create their own lines of vertically differentiated multiple store brands within a product category. As the number of store brands increase, the retailer's shelf space becomes more crowded, which may force the retailer to consider dropping some national brands from its assortment. Despite these trends, the problem of product line design in a vertically differentiated product category has been analyzed mainly from a manufacturer's perspective in the marketing literature and it is not known to what extent the findings of the existing product line design literature provide applicable strategic guidelines for the new problem faced by retailers. In this study, we address this deficiency in the literature and conduct an in-depth study of the retailer's strategic design of a line of store brands and its assortment decision within the context of retail category management. We analyze the retailer's decision about not only how to design a line of store brands but also which national brand to drop from its assortment. The results of our analysis are as follows. First, if the retailer has to drop one of national brands from its assortment, it is the best for the retailer to drop the low-quality national brand rather than the high-quality national brand. Second, the retailer has to position the high-quality store brand relatively close to the high-quality national brand, remained on its shelf, in terms of quality so as to maximize the size of retail margin from the national brand. On the other hand, the retailer should set the quality of the low-quality store brand at a lower level than that of the low-quality national brand to increase the total category demand by attracting more price sensitive consumers. By doing so, the retailer can also minimize cannibalization between two store brands. Lastly, our analysis shows that the introduction of a line of store brands improves consumer welfare by increasing real values of all products on the shelf.

• Carbon letters
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• v.21
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• pp.23-32
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• 2017

A drop weight impact test was conducted in this study to analyze the mechanical and thermal properties caused by the changes in the ratio of carbon fiber reinforced plastic (CFRP) to ethylene vinyl acetate (EVA) laminations. The ratios of CFRP to EVA were changed from 10:0 (pure CFRP) to 9:1, 8:2, 6:4, and 5:5 by manufacturing five different types of samples, and at the same time, the mechanical/thermal properties were analyzed with thermo-graphic images. As the ratio of the CFRP lamination was increased, in which the energy absorbance is dispersed by the fibers, it was more likely for the brittle failure mode to occur. In the cases of Type 3 through Type 5, in which the role of the EVA sheet is more prominent because it absorbs the impact energy rather than dispersing it, a clear form of puncture failure mode was observed. Based on the above results, it was found that all the observation values decreased as the EVA lamination increased compared with the CFRP lamination. The EVA lamination was thus found to have a very important role in reducing the impact. However, the strain and temperature were inversely propositional.

• Journal of the Korean Institute of Gas
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• v.11 no.3
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• pp.1-6
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• 2007

The heat transfer coefficient and pressure drop during gas cooling process of $CO_2$ (R-744) in inclined helical coil copper tubes were investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube, which is specified as the inner diameter of 4.55 mm. The refrigerant mass fluxes were varied from 200 to $600kg/m^2s$ and the inlet pressures of gas cooler were done 7.5 to 10.0 (MPa). The heat transfer coefficients of $CO_2$ in the inclined helical coil tubes increase with the increase of mass flux and gas cooling pressure of $CO_2$. The pressure drop of $CO_2$ in the gas cooler shows relatively good coincidence with those predicted by Ito's correlation developed for single-phase in a helical coil tube. The local heat transfer coefficient of $CO_2$ is well coincident with the correlation by Pitla et al. However, at the region near pseudo-critical temperature, the experiments indicate higher values than the Pitla et al. correlation.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.94-100
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• 2002

During the last years, great progress has been made in the fields of welding power sources and filler materials for the MIG-welding of magnesium alloys. This advice resulted in a better welding process, md, therefore, in highly improved welding results. Furthermore the gap between short-circuiting- and spray-arc-trunsfer could be closed by the triggered short-circuiting- and the short-circuiting-arc with pulse overlay. A crucial contribution to the welding process is the energy input into the filler material. Many problems result from the physical properties of magnesium, for instance its narrow interval between melting point 600$^{\circ}C$ and vaporization point 1100$^{\circ}C$. The energy input into the filler material has to be regulated in such a way that the wire will melt but not vaporize. For th is reason, special characteristics of power sources hue been examined and optimized with the help of high-speed-photographs of the welding process with particular consideration of the drop detachment. An important improvement of the weld seam profile has been achieved by using filler material of only 1.2 mm in diameter. The experiments hue been made with 2.5 mm thick extruded profiles of AZ31 and AZ6l. The results of tensile testing showed strength values of 80 to 100% of the base metal. B ending angles up to 60$^{\circ}$ have been reached. The fatigue strength under reversed bending of the examined magnesium alloys after welding reaches 50% of the strength of the base metal. When the seam reinforcement is ground of the fatigue strength can be raised up to 75% of the base metal.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.519-527
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• 1997

AISI 316 steel has been used extensively for heater and boiler tube of the structural plants such as power, chemical and petroleum plants under severe operating conditions. Usually, material degradation due to microcrack or precipitation of carbides and segregation of impurity elements, is occured by damage accumulated for long-term service at high temperature in this material. In this study, the effect of aging time on fracture toughness was investigated to evaluate the measurement of material degradation. The elastic-plastic fracture toughness behaviour of AISI 316 steel pipe aged at $550^{\circ}C$for 1h-10000h (the aged material) was characterized using the single specimen J-R curve technique and eletric potential drop method at normal loading rate(load-line displacement speed of 0.2mm/min) in room temperature and air environment. The fracture toughness data from above experiments is compared with the $J_{in}$ obtained from predicted values of crack initiation point using potential drop method.