• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.169-173
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• 1988

In order to find out the optimum seeding date of flax. this study was investigated ecological characters, yield components and yield of five varieties(Wiera, Taijungsun ＃$^1$, Storment Goss, CI 1763, 99403-Fiber). As seeding date was delayed, the maturing date was delayed also and stem length was longest in March 10 seeding but it grew short in the late seeding. Oil content was increased most in March 10 seeding, that is, increased to 34% in Taijungsun ＃$^1$, 32% in storment Goss, 30% in Wiera and 26% in 99403-Fiber, and it was decreased in the late seeding. Stem yield and seed yield were heaviest in March 10 seeding, and it was light in the late seeding, Judging from the results reported above. in optimum seeding date of flax seemed to be before the March 10.

• Korean Journal of Materials Research
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• v.9 no.11
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• pp.1083-1087
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• 1999

Microstructures and the gas-sensing characteristics of the $\textrm{SnO}_2$ thin films were studied, which were deposited at various conditions (rf power, sample temperature, $\textrm{O}_2$/Ar ratio) by the rf magnetron sputtering. As a result, six typical microstructures were derived, such as amorphous(A), amorphous mixed with polycrystalline grains (A+P), polycrystalline with random crystalographic orientation (P), fine columnar (FC), coarse columnar (CC) and Zone T (T) with dense fiberous structure. Typically, A, A+ P, and P structures were formed when no $\textrm{O}_2$ was added to the sputter gas, whereas FC, CC, and T structures were obtained when $\textrm{O}_2$ was added. The A structure formed at low rf power and low temperature, the A+P at high rf power and low temperature, and the P at high rf power and high temperature. The FC structure was obtained at low rf power and low temperature. the CC at low rf power and high temperature, and the T at high rf power and low temperature. Results of the gas-sensing test of the sensor chips fabricated from the typical films indicated that the fine columnar microstructure shows the highest sensitivity both at $300^{\circ}C$ and $400^{\circ}C$. It was proposed that this is due to the high specific surface area of the micro-columns.

• The Korean Journal of Zoology
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• v.28 no.3
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• pp.194-208
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• 1985

The ultrastructure of the integumental epidermis of Korean planaria (Dugesia japonica) is studied by light microscope, scanning electron microscope and transmission electron microscope. The planaria has mono-layered integumental epidermis in which most of cells exhibit irregularly columnar shape. The epidermal cells of the integument are classified into six types on the basis of cytochemical and ultrastructural characteristics. 1) Ciliated epithelial cells: These cells have cilia in their free surfaces. The axonemes of cilia exhibits fundamental 9+2 microtubular pattern. 2) Eosinophilic cells: These cells contain a few large eosinophilic granules. The core of eosinophilic granule is consisted of sparsely dispersed fibrillar structures in relatively electron-lucent ground material. 3) Mucous cells: These cells are filled with irregularly shaped, PAS-positive mucous granules which have an average size of $0.8\\times0.3 \\muM$. 4) Rhabdite-forming cells: These cells possess a few strongly-eosinophilic large rhabdite granules. The rhabdite granules are synthesized either in the rhabdite-forming cells which constitute integumental epidermis or in the corresponding cells which are developed in the parenchyma and later transferred to epidermal cells of integumental epidermis through basement membrane. 5) A-type of basophilic granule cells: These granule cells possess round or irregularly-shaped granules which are strongly stained with Alcian blue. These electron-dense granules have an average size of $1.5\\times1.0 \\muM$. This type of cells is derived from parenchymal tissue. 6) B-type of basophilic granule cells: These basophilic granule cells with PAS-positive granules, are found in the epidermis of lateral body wall. The granules, which are about $0.7\\times0.4 \\muM$ in size, occupying most part of this cell type are originated from the parenchyma.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.39-46
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• 2008

Due to the growth in industrialization, potential hazards in subsurface environments are becoming increasingly significant. The extraction of the contaminant from the soil and movement of the water are restricted due to the low permeability and adsorption characteristics of the reclaimed soils. There are a number of approaches to in-situ remediation that are used in contaminated sites for removing contaminants. These include soil flushing, dual phase extraction, and soil vapor extraction. Among these techniques, soil flushing was the focus of the investigation in this paper. Incorporated technique with PVDs has been used for dewatering from fine-grained soils for the purpose of ground improvement by means of prefabricated vertical drain systems. The laboratory model tests were performed by using the flushing tracer solutions for silty soils and recorded the tracer concentration changes with the elapsed time and flow rates. The modeling was intended to predict the effectiveness and time dependence of the remediation process. Modeling has been performed on the extraction, considering tracer concentration and laboratory model test characteristics. The computer model used herein are SEEP/W and CTRAN/W, this 2-D finite element program allows for modeling to determine hydraulic head and pore water pressure distribution, efficiency of remediation for the subsurface environment. It is concluded that the coefficient of permeability of contaminated soil is related with vertical velocity and extracted flow rate. The vertical velocity and extracted flow rate have an effect on dispersivity and finally are played an important role in-situ soil remediation.

• Polymer(Korea)
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• v.29 no.5
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• pp.501-507
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• 2005

Small intestinal submucosa (SIS) had been widely used as a biomaterial without immune rejection responses. SIS sponges prepared by crosslinking with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). SIS powders dissolved in $3\%(v/v)$ acetic acid aqueous solution for 48hrs and freeze-dried. EDC solution ($H_2O$ : ethanol = 5 : 95) as a crosslink agent was used in concentration of 100mM. In vitro, rat-BMSCs seeded in SIS sponges and induced the osteogenesis for 28 days. We have characterized the osteogenic potential of rat-BMSCs in SIS sponges by alkaline phosphatase activity(ALP), n assay, SEM and RT-PCR for osteogenic phenotype. In SEM, all morphology of SIS sponges was regular and showed interconnected pore structure. By RT-PCR analysis, we observed type I collagen expression. These results demonstrate osteogenic differentiation of rat-BMSCs. In conclusion, we confirmed that the morphology of surface, cross-section, and side of SIS sponges were highly porous with good interconnections between each pores, which can support the surface of cell growth, proliferation, and differentiation. This result indicates that SIS sponge is useful for osteogenesis of BMSCs.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.494-501
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• 2012

In the present paper, the ultrasound blood images were measured at both the human radial artery(RA) and common carotid artery(CCA), depending on the age, and the pulsatility index of blood echogenicity(PIBE) was analyzed. In addition, the ultrasound blood images were measured at both RA and CCA of both the stroke patients and the control group, and PIBE was compared. PIBE of RA for the young group was similar with that for the old group ($0.13{\pm}0.11$ and $0.16{\pm}0.03$). PIBE of CCA for the young group, however, was larger than that for the old group ($0.70{\pm}0.21$ and $0.32{\pm}0.01$), and was more variable depending on the subject. Similarly, the fibrinogen concentrations of the patients ($336{\pm}61$ and $340{\pm}126mg/dl$) were more than that of the control group ($264{\pm}38$ and $257{\pm}43mg/dl$), for both RA and CCA. The results indicate the possibility of the ultrasonic test on the correlation between erythrocyte aggregation and stroke, and it is expected that the in-vivo EA measurement would be clinically useful.

• Journal of Conservation Science
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• v.36 no.6
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• pp.562-577
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• 2020

In this study, to conserve the clay seated Vairocana Buddha triad in Seonunsa temple, Gochang (Treasure 1752), the primary materials employed for creating the clay Buddha statues were scientifically analyzed. By analyzing the soil layer constituting the Buddha statues, it is observed that the said layer comprises sand having particle size greater than that of medium sand and soil having particle size smaller than that of fine sand, which were used in a ratio of 7:3, along with the bast fibers of paper mulberry (Broussonetia kazinoki). Hence, the aforementioned soil layer is composed of a mixture of sand and weathered soil, along with bast fibers to prevent scattering. By analyzing the tree species, it is found that the wooden materials constituting the bottom board and the interior of Buddha's sleeves of the Amitabha Buddha statue, Vairocana Buddha statue, and Medicine Buddha statue are hard pines (Pinus spp.). Additionally, three layers are found in the cross section of the gold layer. Furthermore, each of the hair sections of the Buddha statues is composed of earthy materials such as quartz, albite, microcline, mica, and magnetite, and the hair surface was painted by incorporating black materials containing magnetite.

• Composites Research
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• v.36 no.3
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• pp.162-166
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• 2023

Although composite materials are increasingly utilized in general high-strength structures, the demand of performance characteristics as the multifunctional materials has been increased especially in the area of complex electronic devices. While the heat dissipation properties of devices are typically required properties, control of thermal property of composite material especially in the vertical direction is one of the problems to be solved due to its lamination process. In this study, CFRP was manufactured using the Vacuum filtration method for three types of solvent and CFs. In the composite material manufacturing process, the effect of solvent was examined using three solvents where solvents are most frequently used for the dispersion of fibers. Morphology of fiber was observed through a microscope to confirm the arrangement of CFs in the vertical direction. The alignment of fiber was examined through the measurement of the thermal conductivity of the manufactured specimen. For the thermal conductivity measurement, the higher thermal conductivity was obtained with the lower aspect ratio of CF. For the thermal conductivity in the through-plane direction, 8.687 W/m·K, 10.322 W/m·K, and 13.005 W/m·K of thermal conductivity was measured in the DMF, NMP and Acetone, respectively.

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.

• Journal of Korea Port Economic Association
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• v.31 no.4
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• pp.75-89
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• 2015

This study examines 31 import and export cargo items handled in each port to investigate which items face the most competition among the ports and how many of them are transited to other ports. The study aims to suggest implications for the future port policy of Incheon Port. It was found that the volume concentration in the Western Coast region from 2005 to 2014 became increasingly decentralized. The decentralization began in earnest in 2009 in particular, and the value was 0.448 in 2014, indicating fierce competition among the regions. According to the static and dynamic positioning analyses results for Incheon Port, Pyeongtaek and Dangjin Port, and Gunsan Port, using BCG Matrix, the static positioning analysis showed that Incheon Port belongs to the 3rd quadrant (Cash Cows), Pyeongtaek and Dangjin Port belongs to the 2nd quadrant (Question Marks), and Gunsan Port belongs to the (Dogs) group. This implies that Incheon Port has maintained its position with large shares compared to those of other ports, despite its low growth rate. However, the market position and growth rate of Incheon Port decreased according to the dynamic positioning analysis results. The shift-share analysis results indicated that the volumes of Incheon Port and Gunsan Port were shifting to Pyeongtaek and Dangjin Port. Moreover, the ratio of absolute growth to potential growth of Incheon Port and Gunsan Port turned out to be significantly lower than that of Pyeongtaek and Dangjin Port, implying that Incheon Port and Gunsan Port are declining as compared to Pyeongtaek Port and Dangjin Port. According to the LQ index analysis results, specialized items from Incheon Port that do not overlap with other ports included the following ten items: meat, fish and crustaceans, bituminous coals, crude oil and petroleum, petroleum-refined products, plastic rubber and products, textiles, nonferrous metal and products, electric machinery, and aircrafts and ships. In particular, it was confirmed that the bulk cargo of Incheon Port was actually shifting to Pyeongtaek and Dangjin Port following the policy of re-establishing port functions.