• Journal of the Society of Naval Architects of Korea
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• v.35 no.3
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• pp.1-13
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• 1998

In the present paper, the hydrodynamic characteristics of three dimensional hydrofoils moving with a constant speed below the free surface using a higher-order boundary element method based on 9-node Lagrangian curvilinear elements are investigated. A bi-quadratic spline scheme is employed to improve the numerical results on the free surface. To validate the present scheme, the calculated results are compared with the analytic solutions for a submerged sphere and a spheroid showing a good agreement. For the validation of the hydrofoil study, the computed lift and drag of a hydrofoil having $NACA64_{1}A412$ section with aspect ratio(A.R.) of 4 are compared with the experimental data by Wadlin et al.[28]. The comparison covers a number of variations of angle of attack and submergence depth. Then, using an A.R. hydrofoil with NACA0012 section, the free surface on the lift and drag are investigated and these are compared with the previous results. The wave elevations and patterns created by the aforementioned submerged bodies are also investigated with Froude numbers and submergences.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.10-17
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• 2020

Objectives: This study was performed to evaluate the total dust, size-selective dust, and heavy metal concentrations generated inside and outside toll booths on an expressway and to identify the source through analysis of the components of the deposited dust. Methods: A total of 32 samples were collected from eight expressway toll booths. Each total dust sample was collected using a 37 mm PVC filter attached to a personal air sampler. Heavy metal samples were collected according to NIOSH method 7300. The size-selective dust concentrations were identified using a DustMate, and deposited dust was analyzed by WD-XRF and UHR-FE-SEM. Results: The geometric mean concentrations of the total dust inside and outside the toll booths were 337.5 ㎍/㎥ and 342.7 ㎍/㎥, respectively. The overall concentrations of TSP, PM₁₀, PM_2.5, and PM1 were higher on the outside of the toll booths, as the particle size of dust was larger, and higher in the underground passage as the dust size was smaller. The real-time analysis of the dust concentrations of TSP, PM₁₀, PM_2.5, and PM1 revealed to be higher at morning and evening times than other times because of heavy traffic. The element components of deposited dust in the toll booth were related to natural sources rather than artificial sources. Among the chemical components in the deposited dust analyzed by WD-XRF, SiO₂ was the highest. For the elements analyzed by UHR-FE-SEM, C was the highest, followed by O, and Si. Conclusions: In order to reduce the dust concentrations around toll booths on an expressway, it is necessary to periodically clean surrounding areas such as underground passages, and it is also necessary to remove deposited dust inside the toll booth from time to time.

• Economic and Environmental Geology
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• v.33 no.4
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• pp.273-282
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• 2000

In order to investigate the extent and degree of arsenic and heavy metal contamination and the bioavailability of toxic elements around the abandoned mine in Korea, an environmental geochemical survey was undertaken in the Daduk mine. After appropriate preparation, tailings, soil, stream sediment, crop plant and fingernail samples were analysed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of 8,782 mg/kg As, 8.3 mg/kg Cd, 489 mg/kg Cu, 3,638 mg/kg Pb and 919 mg/kg Zn were found in tailings from the Daduk mine. These significant concentrations can impact on soils and sediments around the tailing ponds. Mean concentrations of As, Cd, Pb, Cu and Zn in soils are significantly higher than those in world average soil, especially for As and Pb. Element concentrations in sediments decrease with distance from the tailing ponds due to a dilution effect by the mixing of uncontaminated sediments. Arsenic and Cd are elevated in rice grains and stalks, and Cu and Zn concentrations in chinese cabbage, sesame and bean leaves are higher than the upper limit values for normal plant. Arsenic concentration in fingernails of farmers are higher than the normal level with a maximum value of 1.5 mg/kg. The post-ingestion bioavailability of toxic heavy metals in some paddy and farmland soils has been also investigated using the SBET (simple bioavailability extract test) method. The method utilises synthetic leaching fluids closelyanalogous to those of the human stomach. The quantities of As, Cd, Cu, Pb and Zn extracted from paddy soils after 1 hour indicated 15.9, 65.4, 46.2, 39.4 and 29.4% bioavailability, respectively and for farmland soils, 12.4, 26.0, 31.2, 29.3 and 19.4% bioavailability, respectively. The results of the SBET indicate that regular ingestion of soils by the local population could pose a potential health threat due to long-term toxic element exposure.

• Journal of Environmental Impact Assessment
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• v.16 no.5
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• pp.319-325
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• 2007

Recently, since the risk on natural disasters is increasing due to abnormal weather such as the global warming, a need for a system on prior review on the influence of disasters has emerged in order to establish a solution by analyzing elements of disaster in advance. However, since the inherently destroying business namely the quarrying business is excluded from the range of subject business of Prior Review System on the influence of disasters, a correction for this is required. In order to actually explore how much risk it contains, actual outflow of soil and flood in the quarrying block where quarrying is being currently carried out was examined and the required undercurrent facility capacity which is also used as a grit chamber was investigated. In addition, by comparing the soil outflow of industrial complexes and golf courses which are current subject businesses of Prior Review on the Influence of Disasters and that of rock mountains relative risk level was examined. After investigation, it was found that the risk on occurrence of disasters was increased due to increase in outflow of soil and flood because of the change of land condition during and after development thus an adequate solution to decrease is required. In addition, after comparison with other business groups it was found that a significantly higher amount of soil is outflown in case of rock mountains thus it was analyzed that a solution to decrease is required. Therefore, a correction is immediately required in order to include quarrying business in the subject business of Prior Review System on the Influence of Disasters.

• The Research Journal of the Costume Culture
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• v.4 no.3
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• pp.305-323
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• 1996

The purpose of this sty is to forecast the tendency of clothing colors, to provide materials useful for making the color plan for a better costume, and suggest new information in the apparel industry. To achieve these purposes, this study was carried out by suggesting vogue colors of recent apparel, along with the 20 standard colors of Muncell to 350 men and women in their 20s residing in Taegu.. We analysed and compared their preferred colors in suits vidual factor ;age, sex, education ,skin color, and body shape, and additionally classifying their interest in clothing colors, cause for color selection , degree of interest in color of clothes, color satisfaction of apparel market, and color combination of clothing, color satisfaction of apparel market, and color combination of clothing. We compared these elements according to their age, sex, and education. The results of this study is summarized as follows; 1. It was shown that both men and women in their 20s preferred warm colors the first colors mentioned being the most popular ; Pastels, Red, Blue and Black. They disliked dark and sordid colros in the order of Mauve, Khaki and Red. They preferred wearing Pastels and Yellow in the Spring, White, Blue, and Pastels were the favorites for summer, Beige in autumn, and black, Gray, and Beige in winter. The repugnated colors they chose two wear were Black, Red, Mauve, Khaki in spring and summer. Mauve, Red, Yellow were favorites for autumn, and Blue·White, Yellow·Green, and Pastels in winter. 2. The preferred colors for T-shirts were Yellow, Pastels, White in spring. White and Pastels were summer favorites, Beige an Red for autumn, and Black, Red, Beige in Winter. As for suits, the preferred colors in spring were in the order of Pastels, Beige and Yellow. The preferred colors of upper garments in summer were in the order of White and pastels. for lower summer garments Pastels, White and Blue were favorites. In autumn, Beige was shown to be highly preferred, and in winter, the order of preferred colors was Black, Gray and Beige. 3. On of those individual factors showing the greatest difference was sex. 4. Those factors having the greatest impact on the selection of clothing color were the season and their preference color. 5. The in vogue color of men in their 20s was at a higher level than hat of women. The groups that had an upper college level education showed a significant difference in their choices thant hose who were highschool graduates and technical college student and graduates. The consideration of inteterest in color of clothes, holding clothes during new purchasing, body shape and skin color was higher for women than men. In buying and wearing accessaries, women tend to take into consideration the harmony with the garment, and there was shown a significant difference between highschool graduates and the groups above the level of college education.

• Journal of Surface Science and Engineering
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• v.50 no.3
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• pp.164-169
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• 2017

Ni-Cr-X ternary interlayers were investigated to improve the adhesion of Cu/Ni-Cr/Polyimide flexible copper clad laminates. The ternary compounds are sputtered Ni-Cr-X films (where X is one of Nb, V, Mo, or Ti), and the effect of third elements on the adhesion was evaluated and investigated chemically and mechanically. The feel strength was higher in the order of Ni-Cr-Nb > Ni-Cr-V > Ni-Cr > Ni-Cr-Mo > Ni-Cr-Ti. Nb, which has a comparable standard electrode potential to Cr, increased the adhesion, while Ti, with a low standard electrode potential, degraded the adhesion. The Ni-Cr-Nb interlayer was amorphous, while Ni-Cr-Ti was partially crystalline. The similar morphology structure of the Ni-Cr-Nb interlayer with polyimide resulted in a better adhesion.

• Applied Biological Chemistry
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• v.32 no.4
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• pp.332-337
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• 1989

Rheological properties of rehydrated freeze dried instant rice were investigated in comparison with that of cooked rice. The time changes in reciprocal hardness of instant rice grains at various rehydration temperatures$(60{\sim}90^{\circ}C)$ could be expressed by the first order reaction rate equation regardless of rehydration temperature and reaction rate constant increased as the rehydration temperature increased. Activation energy for rehydrating instant rice was 6.1 kcal/g-mol. Analysis of compressive stress relaxation test showed that the viscoelastic properties of both rehydrated instant rice and cooked rice grains could be expressed by 6-elements generalized Maxwell model. Rehydrated instant rice revealed higher relaxation decay than that of cooked rice and showed the elastic property increased by increasing the rehydration temperature.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.30.3-31
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• 2015

We present a kinematic analysis of 172 likely member galaxies of the Ursa Major Cluster. In order to understand the dynamical state of the cluster, we investigate the correlation of the cluster morphology with rotation, the velocity dispersion profile, and the rotation amplitude parallel to the global rotation direction. Both the minor axis and the rotation are very well-aligned with the global rotation axis in the outer region at half radius (> 0.5 $R_{max}$), but not in the inner region. The cluster exhibits low velocity dispersion and rotation amplitude profiles in the inner region, but higher in the outer. Both profiles exhibit outwardly increasing trends, suggesting an inside-out transfer of angular momentum of dark matter via violent relaxation, as revealed by a recent off-axis major-merging simulation. From Dressler-Schectman plots in the plane of galactic positions, and velocity versus position angle of galaxy, we are able to divide the Ursa Major Cluster into two substructures: Ursa Major South (UMS) and Ursa Major North (UMN). We derive a mass of $3.2{\times}10^{14}M_{\odot}$ for the cluster through the two-body analysis by the timing argument with the distance information (37 for UMN and 36 for UMS) and the spin parameter of ${\lambda}=0.049$. The two substructures appear to have passed each other 4.4 Gyr ago and are moving away to the maximum separation.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.99-103
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• 2003

This paper presents lens optimization of the resolution and the distortion for a four-element lens design. In order to have compact optical system, we used the tele-photo type lens composed of a positive and a negative power elements instead of retro-focus lens. The specifications of optical lens design are the focal length of 7.2 mm, the F/number of 2.8 and the field angle of $54.7^{\circ}C$. The MTF values are higher than 0.5 in the spatial frequency range up to 110 lp/mm for all of the designed object heights. Also, it is expected to fulfill all the requirements of a digital still camera lens and especially suited for building low-cost, compact digital cameras because of the low-profile property of the lens design.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.77-88
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• 2017

Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.