• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.431-438
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• 2009

The main purpose of this research is to prepare and provide basic materials for the propagational strategy of eelgrass by investigating on the morphological adaptation of Korean Zostera marina to ocean currents. An eelgrass plant mainly consists of rhizome, leaf sheath, leaves and roots. The rhizome is the horizontal stem of the plant that serves as the backbone from which the leaves and roots emerge. The leaf sheath is the bundle at the base of the leaves that holds the leaves together, protecting the meristem, the primary growth point of the shoot. Leaves originate from a meristem which is protected by a sheath at the actively growing end of the rhizome. As the shoot grows, the rhizome elongates, moving across or within the sediment, forming roots as it progresses. The aggregated leaves from the leaf sheath are found to have two cell layers on one side and multiple layers of airy tissues called aerenchyma on the other. The aerenchyma tissues are developed in multi-layered cell structures surrounding the veins which are formed in the leaf sheath. Generative shoots are made of rhizomes, which are circular or ovoidal, stem, and spathe and spadix. The transverse section of rhizome and the stem and central floral axis is found to be circular, ovoid and in the shape of convex respectively, and the vascular bundle, which is a part of transport system, has one large tube in the center and two small tubes on both sides. The layers of collenchyma cells numbered from 12 to 15 in the stem, and from 7 to 12 in the rhizome. The seed coat is composed of sclereids, small bundles of sclerenchyma tissues, which prevent the influx of sea water from the outside and help endure the environmental stress. In conclusion, alternative multi-layer structure in circular, convex type aggregated leaf base are interpreted to morphological adaption as doing tolerable elastic structure through movement of seawater. The generative shoots develop long slim stem and branches in circular or ovoidal shapes to minimize the adverse impacts of sea current, which can be interpreted as the plant's morphological adaptation to its environment.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.243-256
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• 2007

The purpose of this paper is aimed at identifying the planting condition of greenbelt axis covering forests located at Sinhyeon-eup, Geoje-si and also establishing improvement plans for the ecological organization. The study was executed with buffer green space designed to mitigate noise, which is located at a halfway point linking Mt. Yukkyo(altitude of 50m) and Mt. Jungmae(altitude of 131m). The number of the biotope patterns was classified into 17 in total: the two are urbanized districts such as a townified district and streets and another 15 are greenbelts and open space such as forest biotope, inland water biotope, and landscaping tree plantations biotope. According to the analysis of biotope types, it was estimated that the making use of already established buffer greens as a linking medium with a foothold of Mt. Yukkyo and Jungmae, whose natural eco-system is well suited for habitation of living organism, is the one and only way to the influx of living organism into the downtown area. The green coverage rate of the base green area, sub-base green area and linkage green area was 160.29%, 128.37% and 44.37% respectively; the green capacity coefficient(i.e. GVZ[$Gr{\ddot{u}}nvolumezahl$]) for base green area, sub-base green area and linkage green area was $4.04m^3/m^2,\;3.95m^3/m^2\;and\;0.65m^3/m^2$ respectively. The base green area has constituted multi-layered vegetation structure and thus played a role as habitats for living organism and supply centre of species, whereas the sub-base green area has destroyed lower layer vegetation, and the linkage green area was in bad shape due to the lack of planting volume and damage of the shrub layer. Accordingly, this research paper intended to suggest detailed implementation plans for the improvement in landscape for city dwellers' use and relaxation; in other words, this paper focused on ecological build-up for the Influx of wild birds into the downtown area for the promotion of bio-diversity of species through the linkage of base green areas and the fostering of nature observing trails for citizens as well as the connecting of green areas through the build-up of roadside greens to make these green areas to be efficiently used as corridors for the influx of wild birds and bio-organism habitation and for citizens' using space.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.4-23
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• 2020

The purpose of this study was to explore the diversity of Korea's iron casting technology and to examine various casting methods. The study involved a literature review, analysis of artifacts, local investigation of production tools and technology, and scientific analysis of casting and cast materials. Bellows technology, or Bulmi technology, is a form of iron casting technology that uses bellows to melt cast iron before the molten iron is poured into a clay cast. This technology, handed down only in Jeju Island, relies on use of a clay cast instead of the sand cast that is more common in mainland Korea. Casting methods for cast iron pots can be broadly divided into two: sand mold casting and porcelain casting. The former uses a sand cast made from mixing seokbire (clay mixed with soft stones), sand and clay, while the latter uses a clay cast, formed by mixing clay with rice straw and reed. The five steps in the sand mold casting method for iron pot are cast making, filling, melting iron into molten iron, pouring the molten iron into the cast mold, and refining the final product. The six steps in the porcelain clay casting method are cast making, cast firing, spreading jilmeok, melting iron into molten iron, pouring the molten iron, and refining the final product. The two casting methods differ in terms of materials, cast firing, and spreading of jilmeok. This study provided insight into Korea's unique iron casting technology by examining the scientific principles behind the materials and tools used in each stage of iron pot casting: collecting and kneading mud, producing a cast, biscuit firing, hwajeokmosal (building sand on the heated cast) and spreading jilmeok, drying and biyaljil (spreading jilmeok evenly on the cast), hapjang (combining two half-sized casts to make one complete cast), producing a smelting furnace, roasting twice, smelting, pouring molten iron into a cast, and refining the final product. Scientific analysis of the final product and materials involved in porcelain clay casting showed that the main components were mud and sand (SiO₂, Al₂O₃, and Fe₂O₃). The release agent was found to be graphite, containing SiO₂, Al₂O₃, Fe₂O₃, and K₂O. The completed cast iron pot had the structure of white cast iron, comprised of cementite (Fe₃C) and pearlite (a layered structure of ferrite and cementite).

• (The) Research of the performance art and culture
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• no.22
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• pp.93-121
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• 2011

This article is concerned with the withdrawal of the compositional principle of Jinogigut which has been performed in Seoul and the identification of its meaning based on the withdrawal. Jinogigut is a world where a god is connected to humans in complicated manners, this world and the world of the dead coexist, and it is a process of demonstrating that the dead, who have stayed in the world of humans, enter the world of a god. Jinogigut shows the process of leading the dead to the world of the dead one after another. First, the god-centered street is continued, and the gut displays through which process a god will guide the dead to the world of the dead. Next, is a human-centered street, which exhibits the appearance of the dead heading to the world of the dead following the death angel, more in detail. Finally, a human-centered structure shows how humans enter the world of the dead. Through this repetition, it reveals that the dead take a seat in the world of the dead, at last. The organization of the later part of the world of the dead-oriented gut in Jinogigut, which is god-centered, continues to a human-centered gut through the meeting between a god and humans. and , which are continued, followed by , are ceremonial rituals that confirm the dead entering the world of the dead without any problem. Begareugi shows that the entering of the dead into the world of the dead was completed with perfection by cutting hemp cloth, and informs the living that the dead expressed gratitude for holding the ritual for him/her by appearing at the venue of the gut once again and that the dead settled into the world of death. , which finally holds ancestral rites to the god of ancestors who is seated in the world of the dead, reveals that the dead, who had been a human, has been transformed into the god of ancestors through Jinogigut. Jinogigut also performs the function of comforting a client (who is the family of the dead) of the gut, who has faced a sudden death in his/her family. What is the most important for consoling the client is to display that the dead has entered the world of the dead without any problem. Jinogigut shows this process through a three-layered structure. It exhibits how the dead would be moved to the world of gods, as well as the safe entering of the dead who followed Jeoseung-saja(envoy from the world of the dead) and who had appeared to this world from the world of the dead. Then, it demonstrates again the appearance of the dead entering the world of the dead following Barigongu; thus, it placates the heart of the client's family.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.220-237
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• 2021

This study carried out the conservation treatment for the mattress put on the bed, which is one of 4 items in National Folklore Cultural Heritage, the Red-lacquered Furniture with the inlaid mother-of-pearl design used by Empress Sunjeonghyo (presumed), after identifying the characteristics of the manufacturing techniques and the used materials. And the study intends to compare it with the mattress placed in the Daejojeong in the Changdeokgung Palace in order to identify the characteristics of mattresses domestically used during the 1920s and 1930s. From the analysis of the mattress presumably used by Empress Sunjeonghyo, it was identified that the mattress frame was made of pinaceous hemlock spruce while the webbing and twine in the structural parts were made of jute. The findings are as follows: the burlap had a filling material that was made of jute; the straw mat was made from Oryza; and, the rest of the filling material was cotton. Rayon was used for the top cover while cotton was used for the bottom. As a result of research on the materials and the inner structure, it was found that mattress was manufactured in the form of the upholstery style mainly found in chairs and day-beds in Western furniture. Based on analysis results, materials identical to the original were adopted during the conservation treatment. Next, the process of dismantling, cleaning, repair, reinforcement and assembling was conducted. During the dismantling process, the top cover was newly discovered and some letters (Yokohama, Kobe, and Joseon) were found in the burlap filling, but there was no trace which can clarify its maker or production place. dry cleaning was carried out on the structural parts, filling materials, and the cover, and then the repair and reinforcement were done, preserving the existing materials in the upholstery structure and using the same materials for conservation. The webbing in the structural parts was reinforced using materials identical to the original, and the twine was used for arranging and fixing the springs into wooden frames. For the damaged cotton cloth and burlap, reinforcement materials identical to the original were put over it and sown. For the damaged area of the top cover, reinforcement cloth was cut and then added inside and the damaged area was sown. Assembling was carried out in the reverse order of the dismantling. After the burlap identical to the original material was inserted into the areas in contact with the springs and then fastened, a filling pad, reinforcement cloth, a straw mat, cotton cloth, cotton felt, wide cotton cloth for protecting the cover, and the cover were layered and fastened with tacks. The two mattresses used by Empress Sunjeonghyo differed only by the period of production and followed the same Western upholstery style consisting of the frames, filling materials, and covers. During the conservation treatment process, a velvet cover was newly discovered and the traces of repair in the past were found. Furthermore, identifying straw mats, straw bags, and straws for filling material, this study confirmed changes in the materials used according to the production environment. In the future, it is expected to see changes in the conservation materials during the conservation treatment and manufacturing techniques used for chairs and sofas in the upholstery style belonging to the modern cultural artifacts.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.292-292
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• 2016

Transition metal dichalcogenides (TMDs) with a two-dimensional layered structure have been considered highly promising materials for next-generation flexible, wearable, stretchable and transparent devices due to their unique physical, electrical and optical properties. Recent studies on TMD devices have focused on developing a suitable doping technique because precise control of the threshold voltage ($V_{TH}$) and the number of tightly-bound trions are required to achieve high performance electronic and optoelectronic devices, respectively. In particular, it is critical to develop an ultra-low level doping technique for the proper design and optimization of TMD-based devices because high level doping (about $10^{12}cm^{-2}$) causes TMD to act as a near-metallic layer. However, it is difficult to apply an ion implantation technique to TMD materials due to crystal damage that occurs during the implantation process. Although safe doping techniques have recently been developed, most of the previous TMD doping techniques presented very high doping levels of ${\sim}10^{12}cm^{-2}$. Recently, low-level n- and p-doping of TMD materials was achieved using cesium carbonate ($Cs_2CO_3$), octadecyltrichlorosilane (OTS), and M-DNA, but further studies are needed to reduce the doping level down to an intrinsic level. Here, we propose a novel DNA-based doping method on $MoS_2$ and $WSe_2$ films, which enables ultra-low n- and p-doping control and allows for proper adjustments in device performance. This is achieved by selecting and/or combining different types of divalent metal and trivalent lanthanide (Ln) ions on DNA nanostructures. The available n-doping range (${\Delta}n$) on the $MoS_2$ by Ln-DNA (DNA functionalized by trivalent Ln ions) is between $6{\times}10^9cm^{-2}$ and $2.6{\times}10^{10}cm^{-2}$, which is even lower than that provided by pristine DNA (${\sim}6.4{\times}10^{10}cm^{-2}$). The p-doping change (${\Delta}p$) on $WSe_2$ by Ln-DNA is adjusted between $-1.0{\times}10^{10}cm^{-2}$ and $-2.4{\times}10^{10}cm^{-2}$. In the case of Co-DNA (DNA functionalized by both divalent metal and trivalent Ln ions) doping where $Eu^{3+}$ or $Gd^{3+}$ ions were incorporated, a light p-doping phenomenon is observed on $MoS_2$ and $WSe_2$ (respectively, negative ${\Delta}n$ below $-9{\times}10^9cm^{-2}$ and positive ${\Delta}p$ above $1.4{\times}10^{10}cm^{-2}$) because the added $Cu^{2+}$ ions probably reduce the strength of negative charges in Ln-DNA. However, a light n-doping phenomenon (positive ${\Delta}n$ above $10^{10}cm^{-2}$ and negative ${\Delta}p$ below $-1.1{\times}10^{10}cm^{-2}$) occurs in the TMD devices doped by Co-DNA with $Tb^{3+}$ or $Er^{3+}$ ions. A significant (factor of ~5) increase in field-effect mobility is also observed on the $MoS_2$ and $WSe_2$ devices, which are, respectively, doped by $Tb^{3+}$-based Co-DNA (n-doping) and $Gd^{3+}$-based Co-DNA (p-doping), due to the reduction of effective electron and hole barrier heights after the doping. In terms of optoelectronic device performance (photoresponsivity and detectivity), the $Tb^{3+}$ or $Er^{3+}$-Co-DNA (n-doping) and the $Eu^{3+}$ or $Gd^{3+}$-Co-DNA (p-doping) improve the $MoS_2$ and $WSe_2$ photodetectors, respectively.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.206-211
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• 2003

Effects of substrates and buffer layer upon the formation of crystalline phases and ferroelectricity of $YMnO_3$ thin films were investigated. The hexagonal $YMnO_3$ was easily formed on Si(100) while the mixed phases, hexagonal and orthorhombic $YMnO_3$, on $Pt(111)/TiO_2/SiO_2/Si$ substrate. When the $Y_2O_3$ buffer layer of 70 nm thick was inserted between the substrates and the $YMnO_3,$ the c-axis oriented hexagonal single phase formed on both substrates, Si(100) and $Pt(111)/TiO_2/SiO_2/Si$. The leakage current density of the hexagonal $YMnO_3$ thin films was lower than that consisting of mixed phases, hexagonal and orthorhombic. Furthermore the hexagonal $YMnO_3$ with c-axis preferred orientation showed the lowest leakage current density. The remnant polarization from a P-E hysteresis curve for the $YMnO_3$ formed on Si(100) was 0.14 without buffer layer and $0.24_{mu}C/cm^2$ for that with buffer layer. For the $Pt(111)/TiO_3/SiO_3/Si$ substrates, the specimen without $Y_2O_3$buffer layer did not show the hysteresis curve, while the buffer-layered has the remnant polarization of $1.14_{mu}C/cm^2$. It was concluded that the leakage current density and the ferroelectricity for the $YMnO_3$ thin films could be controlled by varying crystalline phases and their preferred orientation which depend on the kind of substrates and whether the $Y_2O_3$buffer layer exist or not.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.1 s.55
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• pp.45-51
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• 2006

In the field of makeup cosmetics, especially, powder-based foundations such as two-way cake, pact and face powder, the quality of which is known to be strongly influenced by the properties of powder, surface treatment technology is widely used as a method to improve the various characteristics of powder texture, wear properties, dispersion ability and so on. The two-way cake or pressed-powder foundation is one of the familiar makeup products in Asian market for deep covering and finishing purpose. In spite of the relent progress in surface modification method such as composition of powders with different characteristics and application of a diversity of coating ingredient (metal soap, amino acid, silicone and fluorine), this product possess a technical difficulty to enhance both of the adhesion power and spreadability on the skin in addition to potential claim of consumer about heavy or thick feeling. This article is covering the preparation and coating method of nano-vesicle that mimic the double-layered lipid lamellar structure existing between the corneocytes of the stratum corneum in the skin for the purpose of improving both of two important physical characteristic of two-way cake, spreadability and adhering force to skin, and obtining better affinity to skin. Nano-vesicle was prepared using the high-pressure emulsifying process of lecithin, pseudo ceramide, butylene glycol and tocopheryl acetate. This nano-sized emulsion was added to powder-dispersed aqueous phase together with bivalent metal salt solution and then the filtering and drying procedure was followed to yield the nano-vesicle coated powder. The amount of nano-vesicle coated on the powder was able to regulated by the concentration of metal salt and this novel powder showed the lower friction coefficient, more uniform condition of application and higher adhesive powder comparing with the alkyl silane treated powder from the test result of spreadability and wear properties using friction meter and air jet method. Two-wav cake containing newly developed coated powder with nano-vesicle showed the similar advantages in the frictional and adhesive characteristics.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.41-47
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• 2003

For the development of low temperature anode-supported planar solid oxide fuel cell, the planar anode supports with the thickness of 0.8 to 1 mm and the area of 25, 100 and $150\;cm^2$ were fabricated by the tape casting method. The strength, porosity, gas permeability and electrical conductivity of the planar anode support were measured. The porosity of anode supports sintered at $1400^{\circ}C$ and then reduced in$H_2$ atmosphere was increased from $45.8\%\;to\;53.9\%$. The electrical conductivity of the anode support was $900 S/cm\;at\; 850^{\circ}C$ and its gas permeability was 6l/min at 1 atm in air atmosphere. The electrolyte layer and cathode layer were fabricated by slurry dip coating method and then had examined the thickness of $10{\mu}m$ and the gas permeability of 2.5 ml/min at 3 atm in air atmosphere. As preliminary experiment, cathode multi-layered structure consists of LSM-YSZ/LSM/LSCF. At single cell test using the electrolyte layer with thickness of 20 to $30{\mu}m$, we achieved $300\;mA/cm^2$ and 0.6V at $750^{\circ}C$

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.587-609
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• 2019

Short-and long-term stabilities of bentonite, favored material as buffer in geological repositories for high-level waste were reviewed in this paper in addition to alternative design concepts of buffer to mitigate the thermal load from decay heat of SF (Spent Fuel) and further increase the disposal efficiency. It is generally reported that the irreversible changes in structure, hydraulic behavior, and swelling capacity are produced due to temperature increase and vapor flow between $150{\sim}250^{\circ}C$. Provided that the maximum temperature of bentonite is less than $150^{\circ}C$, however, the effects of temperature on the material, structural, and mineralogical stability seems to be minor. The maximum temperature in disposal system will constrain and determine the amount of waste to be disposed per unit area and be regarded as an important design parameter influencing the availability of disposal site. Thus, it is necessary to identify the effects of high temperature on the performance of buffer and allow for the thermal constraint greater than $100^{\circ}C$. In addition, the development of high-performance EBS (Engineered Barrier System) such as composite bentonite buffer mixed with graphite or silica and multi-layered buffer (i.e., highly thermal-conductive layer or insulating layer) should be taken into account to enhance the disposal efficiency in parallel with the development of multilayer repository. This will contribute to increase of reliability and securing the acceptance of the people with regard to a high-level waste disposal.