• Economic and Environmental Geology
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• v.33 no.6
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• pp.505-517
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• 2000

This study was undertaken to provide a drinking water quality on the basis of physicochemical properties. In this study, the 25 samples of supply waters of the Taejon area were sampled twice (February and August in 1999). Hydrochemistry of the supply water belongs to the $Ca^{2＋}$-${HCO_3}^{-1}$ type, whereas the supply water was characterized by the relatively significant enrichment of ${Ca}^{2+}$, ${Na}^{2+}$, ${K}^{2+}$, ${Cl}^{2+}$ ions and heavy metals compared to the original water from the Daecheong lake. Generally, the supply water has a mean values for $10.7^{\circ}C$ of temperature, 6.86 of pH, -12 mV of Eh, 88 ${\mu}S$/cm of EC and 70.379 mg/l of TDS in February, whereas the waters of the same sites in August are a slightly high temperature ($26.1^{\circ}C$), TDS (78.069 mg/l) and extremely high EC (442 ${\mu}S$/cm) value. These values are similar with physicochemical properties of the original lake water depending on the seasonal differences. Results of speciation calculation indicate that potentially toxic ions might exist mainly in the forms of free metal (${Cu}^{2+}$ or ${Zn}^{2+}$) and a small amount of ${CO_3}^{2-}$and ${OH}^{-}$in the supply water. The water seemed to be in equilibrium with kaolinite field of the normal stability diagrams for the natural water. Based on enrichment parameter of the supply water normalized by original lake water composition, the average value of those parameter can be calculated with nearly 1.00, but the those values for Cu＋Zn possible source of decrepit pipe lines are 126.75 in February and 115.63 in August samples. The parameter values varied with sampling sites, however, do not exceed by chemistry of drinking water standard. Solid compounds remained on the membrane filter papers after filtration are adhered to pale yellow or yellowish brown colored dissolved solids and precipitates, which are coated by 0.02 to 0.35 mm thick per 500 ml with colloidal particles of about 1 to 2${\mu}m$ size. The particles are mainly Fe-Cu-Zn compounds and partly detected to Mn and Pb.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.59-70
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• 2016

Packaging is thought to contribute to the consumers' purchasing choice of the powdered infant formula products. In Asian market, the products of international and local brands are competing. Evaluation and analysis of food package functions for a variety of brand products will be helpful for the innovative packaging development. Thus, the packaged products of powdered infant formula were collected in Chinese, Indonesian and Korean supermarkets as a typical Asian market and examined in terms of main food packaging functions. Metal cans were the most dominant type of big size package (800-1000 g) while flexible bags were often the common one of medium size (400 g). In general, convenience function was provided in forms of easy opening device and portioning take-out spoon. Information on primary and secondary shelf lives was given besides nutritional facts and use instruction for communication function. The combination of $N_2$ and $CO_2$ was usually employed to protect powdered infant formula in rigid packages, whereas only $N_2$ was used to protect product in most flexible packages.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.735-746
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• 2002

The task of plastic theory is twofold: first, to set up relationships between stress and strain that adequately describe the observed plastic deformation of metals, and second, to develop techniques for using these relationships in studying of the mechanics of metal forming processes, and the anlaysis and design of structures. One of the major problems in the theory of plasticity is to describe the behavior of work-hardening materials in the plastic range for complex loading histories. This can be achieved by formulating constitutive laws either in the integral or differential forms. To adequately predict the response of steel members during cyclic loading, the hardening rule must account for the features of cyclic stress-strain behavior. Neithe of the basic isotropic and kinematic hardening rules is suitable for describing cyclic streess-strain behavior, although a kinematic hardening rule describes the nearly linear portions of the stabilized hystersis loops. There is also a limited expansion of the yield surface as predicted by the isotropic hardening rule. Strong ground motions or wind gusts affect the complex and nonproportional loading histories in the inelastic behavior of structues rather than the proportional loading. Nonproportional loading is defined as externally applied forces on the structure, with variable ratios during the entire loading history. This also includes the rate of time-dependency of the loads. For nonproportional loading histories, unloading may take place along a chord instead of the radius of the load surface. In such cases, the shape of the stress-strain curve has to be determined experimentally for all non-radial loading conditions. The plasticity models including two surface models ae surveyed based on a yield surface and a bound surface that represent a state of maximum stress. This paper is concerned with the improvement of a plasticity models of the two-surface type for structural steel. This is follwed by an overview of plasticity models on structural steel. Finally the need for further research is identified.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.373-382
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• 2016

Painting or thermally sprayed metal coating is often used in corrosion protection of steel structures. In recently, duplex coating system which combines thermally sprayed metals with paint is selected as a new generic type of coatings on steel structures under the highly corrosive environments. In this study, the structural steel specimens were surface treated, thermally sprayed with zinc, zinc-15%aluminum alloy, aluminum and aluminum-5%magnesium alloy, and finally sealing or painted with acrylic urethane. And as a reference specimens, steel specimens were painted with acrylic urethane after surface treatment. Circular defects with 1.0, 3.0 and 5.0 mm in diameters and line defect with 2.0 mm width, which reach the steel substrate were created on all specimens. The specimens were exposed into an environmental testing chamber controlled by the ISO 20340, which is a laboratory cyclic accelerated exposure test condition of spraying/UV/low temperature, for up to 175 days. Based on the corrosion tests, corrosion deterioration from the initial defects were evaluated and weathering performance of the specimens are compared.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.525-532
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• 2014

Since mine wastes were merely dumped in the mine waste dump, they have produced acid mine drainage (AMD). Therefore, main objective of this study was to evaluate the effect of coal combustion products (CCPs) on heavy metal stabilization and detoxification for mine wastes. Total six treatments for incubation test were conducted depending on mixing method (completely mixing and layered). Also, lysimeter experiment was conducted to examine efficiency of polyacrylamide (PAM) on reduction of mine wastes erosion. Result of incubation test showed that concentrations of soluble aluminium (Al) and iron (Fe) in leachate decreased compared to control. The lowest soluble Al and Fe in leachate was observed in 50% mixed treatment (14.2 and $1.03mg\;kg^{-1}$ for Al and Fe respectively) compared to control treatment (253.0 for Al and $52.6mg\;kg^{-1}$ for Fe). The pH of mine wastes (MW) and leachate increased compared to control after mixing with CCPs and ordered as control (MW 6.4, leachate 6.3) < 10% (MW 7.7, leachate 7.1) < 20% (MW 9.0, leachate 7.8) < 30% (MW 9.5, leachate 8.3) < 40% (MW 9.9, leachate 8.5) < 50% (MW 10.5, leachate 8.6). Application of PAM, both in liquid and granular type, dramatically decreased the suspended solid (SS) concentration of CCPs treatments. Reduction of SS loss was ordered as MW70CR30L ($24.4mg\;L^{-1}$) > MW70CR30LPL ($6.7mg\;L^{-1}$) > NT ($3.1mg\;L^{-1}$) > MW70CR30M ($1.6mg\;L^{-1}$) > MW70CR30MPL ($1.1mg\;L^{-1}$) > MW70CR30PGM ($0.7mg\;L^{-1}$) > MW70CR30LPG ($0.5mg\;L^{-1}$) > MW70CR30MPG ($0.4mg\;L^{-1}$). Overall, application of CCPs can be environmental friendly and cost-effective way to remediate coal mine wastes contaminated with heavy metals. In addition, use of PAM could help to prevent the erosion coal mine wastes in mine waste disposal area.

• Korean Journal of Materials Research
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• v.4 no.6
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• pp.681-686
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• 1994

Microwave Detector Using $YBa_{2}Cu_{3}O_{7-x}$, Grain Boundary Junction $YBa_{2}Cu_{3}O_{7-x}$ superconductor thin films were deposited on $LaAIO_{3}$ (100) single crystal substrates using a metal organic chemical vapor deposition (MOCVD) method. These films showed the critical temperature of about 9OK and critical current density of over $10^5/A \textrm{cm}^2$at 77K. These films showed granular structure with 0.5~1.5$\mu \textrm{m}$ grains. Bridge-type junctions, 6$\mu \textrm{m}$ in width and 6pm in length, were fabricated using the photolithography and the Ar ion milling techniques. Current-voltage (I-V) characteristics of these junctions with the microwave irradiation at 77K were studied. The critical current densities decreased as the irradiated microwave power increased. When microwaves were irradiated on the bridge at 77K. the I-V charateristics showed constant voltage stcp(Shapiro steps) at $\Delta$=nho/2e.

• Journal of Energy Engineering
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• v.15 no.1 s.45
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• pp.52-59
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• 2006

This paper examined the conversion of methane to hydrogen and other higher hydrocarbons using dielectric barrier discharge with AC pulse power. Two metal electrodes of a coaxial-type plasma reactor were separated by gas gap and an alumina tube. The inner electrode was located inside the alumina tube. The alumina tube was located inside the stainless steel tube, which was used as the outer electrode. Effect of feed gas composition (methane, oxygen, argon, water and helium), flow rate, applied frequency, input volt-age on methane conversion and product distribution were studied. The major products of plasma chemical reactions were ethylene, ethane, propane, buthane, hydrogen, carbon monoxide and carbon dioxide. The increment of applied voltage and the usage of inert gas as the background (helium and argon) enhanced the selectivity of hydrocarbons and methane conversion. The addition of water in the feed stream enhanced the conversion of methane and yield of hydrogen. Higher voltage leads to higher yield of $C_2H_6,\;C_3H_8,\;C_4H_{10}$ and yield or $C_2H_2\;and\;C_2H_4$ appeared highly in lower voltage.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.588-601
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• 2013

In geophysics and geophysical exploration fields, we can use information about inclination and azimuth in various ways. These include borehole deviation logging for inversion process, real-time data acquisition system, geophysical monitoring system, and so on. This type of information is also necessarily used in the directional drilling of shale gas fields. We thus need to develop a subminiature, low-powered, multi-functional inclination and azimuth measurement system for geophysical exploration fields. In this paper, to develop real-time measurement system, we adopt the high performance low power Micro Control Unit (made with state-of-the-art Complementary Metal Oxide Semiconductor technology) and newly released Micro Electro Mechanical Systems Attitude Heading Reference System sensors. We present test results on the development of a multifunctional real-time inclination and azimuth measurement system. The developed system has an ultra-slim body so as to be installed in 42mm sonde. Also, this system allows us to acquire data in real-time and to easily expand its application by synchronizing with a depth encoder or Differential Global Positioning System.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.186-195
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• 2011

Historically, Korea has made and weaved beautiful jewelry based on delicate metal craft technique. Especially jewelries in Chosun dynasty among these jewelry shows practicality, fanciness and social symbolism at the same time, which is one of representative cultural origins to express characteristics of Korean culture. Since jewelry of imperial princess YEONG, an object of a study herein, was made for a court ceremony although it is an artifact of the end of Chosun dynasty after the time of enlightenment, it is expected be made based on traditional shape and standard in accordance with strictly respected court dress code in Chosun dynasty. It is also an important data of research for a court style and system as well as its artistry in its diversity of type, preservation condition similar to original form and its producers who are master craftsman parted in Sang-Uiwon (an institute in charge of dress and accessaries of court) at the end of dynasty. Thus, a study herein aims to research formatively valuable 11 selected jewelries among jewelries of imperial princess YEONG used at the end of Chosun dynasty, and search for industrial application method with digitalization of the shape and design and preservation of original form of traditional culture. Moreover, in accordance with proposing design data through review of traditional women jewelry, it aims to suggest possibility of application into modern jewelry design and cultural industry.

• Journal of the Korean Society of Costume
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• v.35
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• pp.17-44
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• 1997

Medieval European practical art and style of costume is studied through referring to the literatures. The type of clothing that was seen on tapestries arts and crafts paintings and wall paintings and appeared in the architecture such as church. There were symbolic aspects of color motifs at this period and some restraints for clothing according to the social class, It was a period that draped garments due to the War of Crusades is appeared. Be-cause the medieval taste and decorative character is not only 'formative art' but also the taste beyoud 'mode' and atomsphere of that times it could be seen the strong reflec-tion of customs in the clothing of that times which is shown in works of art. 1) The purpose of Christian art which was found in mosaics stained glasses wall pain-tings and statues of architecture was not just the revival of natural phenomena but visuali-zation of sacred and invisible things. It was valuable to understandin of the spiritual through the sense organ It was a monumental art that was combined with decorative func-tion and role of the Bible. It revealed what was about the religious spiritual miracle, 2) In the medieval European painting characteristic and beautiful creativity was the basis of an argument. Both "Worship of East-ern" that is painted ion a parchment and "Cor-onation of Charles VI" were described decor-ation motifs on the edge of buildings geo-metric patterns and others with outstanding skill. there were precise technologic skill of architect and glassmen and lots of patience of craftsmen. " The Labour of the Months" and the scene of"A Trial at the Court" is also de-scribed elaborately. 3) Tapestry was developed in France Ger-many Swiss at the 14th century. Religionary and historical themes unicorn lady bird flowering plants and others were major motifs. It was very important as decorative wall coverings and as practical door arch and bed hangings. It was made through patient hard work with simple technique and it was con-sidered as an art for practical use. Tapestry was what everyone wish to have. It is reckoned for the item of the best gift. The royalty and nobility ordered and used custom-made tapestries. Sometimes the subject of motifs consisted of series which were deeply related to living 4) Decorative arts and crafts was the art that used materials such as precious metals jewels and others and that accorded with the luxurious and gorgeous taste of the royalty and nobility. Christian considered splendid and beautiful color of light as a symbol of glory. They used also for church appliances, There were metal crafts wood crafts textile crafts and others, As was stated above the costume appeared on the arts and crafts for living revealed the process of changes saw how the politic econ-omic and social organizations were developed.and social organizations were developed.