• Journal of Conservation Science
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• v.32 no.2
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• pp.261-271
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• 2016

We have investigated relationship between particle characteristics of oyster shell powder pigments and their performance such as workability and durability. Three types of the powder which have different particle size and shape(spherical, elliptical, columnar and irregular) distributions were made for this study and we evaluated spreadability and uniformity for workability, and adhesion and surface hardness for durability of painted films by each powder paints. As a result, we found out that the workability and durability of the paints were influenced by the particle shape distribution more than the particle size distribution. The durability, especially, was enhanced as the ratio of columnar particles in the powders was increased. This result verifying the important factor affecting the durability can be base data for selecting oyster shell white paint and assessing its quality for conservation and restoration of Dancheong, as well as to produce high quality traditional paints.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.433-439
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• 1986

Abundant amount of Chiamydia trachomatis could be amplified in mammalian McCoy cells and purified using descontinuous Uroarafin gradient centrifugation. As a chemical means io increase the Chlamydia trachomatis inclusions in McCoy cells IUdR treatment was found to be more effective than the cycloheximide treatment and was recommendanble for the proliferation of Chlamydia trachomatis. Centrifugation promoted Chlamydia trachomatis adhesion to McCoy cell surface, and maximal percentage of infected cells was obtained at about 3000g. The purified Chlamydia trachomatis could be kept in SPG solution for 48 hours at +4$^{\circ}C$ but for longer storage freezing to -7$0^{\circ}C$ was necessary.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.684-692
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• 2016

Acute respiratory virus infectious diseases are a growing health problem, particularly among children and the elderly. Much effort has been made to develop probiotics that prevent influenza virus infections by enhancing innate immunity in the respiratory tract until vaccines are available. Lactobacillus plantarum GB-LP2, isolated from a traditional Korean fermented vegetable, has exhibited preventive effects on influenza virus infection in mice. To identify the molecular basis of this strain, we conducted a whole-genome assembly study. The single circular DNA chromosome of 3,284,304 bp was completely assembled and 3,250 protein-encoding genes were predicted. Evolutionarily accelerated genes related to the phenotypic trait of anti-infective activities for influenza virus were identified. These genes encode three integral membrane proteins, a teichoic acid export ATP-binding protein and a glucosamine - fructose-6-phosphate aminotransferase involved in host innate immunity, the nonspecific DNA-binding protein Dps, which protects bacteria from oxidative damage, and the response regulator of the three-component quorum-sensing regulatory system, which is related to the capacity of adhesion to the surface of the respiratory tract and competition with pathogens. This is the first study to identify the genetic backgrounds of the antiviral activity in L. plantarum strains. These findings provide insight into the anti-infective activities of L. plantarum and the development of preventive probiotics.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.93-101
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• 2011

The evaluation of various color coating methods for color maintenance of color asphalt pavement is conducted using the laboratory and field tests on the bus lane. The surface of color asphalt constructed on the bus lane is deteriorated such as changing color and decoloration and abrasion due to the passing of the traffic and time. The total of 9 coating methods were evaluated in this study. The laboratory tests included Ultra violet test, adhesion test and Taber abrasion test and the field tests were british pendulum test and visual survey. The results of tests showed that the different methods showed the their own engineering characteristics and it is dependant upon the main material used. The rubber epoxy material for the main material showed the satisfactory result among the methods tested. However, the performance of the coating methods after 100days are not satisfactory, decoloration, abrasion and peeling up are investigated and need to be studied for the further application in the field.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.42.2-42.2
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• 2011

$TiO_2$ films were modified by adding a glass frit as a light scattering particle and applied to an anode electrode in dye-sensitized solar cells (DSSCs) to enhance the adhesion between $TiO_2$ and fluorine doped transparent oxide (FTO). Low melting point glass frits at contents of (3 to 7wt%) were added to the nano crystalline $TiO_2$ films. The light scattering properties, photovoltaic properties and microstructures of the photo electrodes were examined to determine the role of the low glass transition temperature ($T_g$) glass frit. Electrochemical impedance spectroscopy, Brunauer-Emmett-Teller method and scratch test were conducted to support the results. The DSSC with the $TiO_2$ film containing 3wt% low Tg glass frit showed optimal performance (5.1%, energy conversion efficiency) compared to the $TiO_2$-based one. The photocurrent density slightly decreased by adding 3wt% of the frit due to its large size and non conductivity. However, the decrease of current density followed by the decrease of electron transfer due to the large frit in $TiO_2$ electrode was compensated by the scattering effect, high surface area and reduced the electron transfer impedance at the electrolyte-dye-$TiO_2$ interface. The stability of the photo electrodes was improved by the frit, which chemically promoted the sintering of $TiO_2$ at relatively low temperature ($450^{\circ}C$).

• Korean Journal of Materials Research
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• v.21 no.1
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• pp.21-27
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• 2011

A nano-porous structure of tin oxide was prepared using an anodic oxidation process and the sample's electrochemical properties were evaluated for application as an anode in a rechargeable lithium battery. Microscopic images of the as-anodized sample indicated that it has a nano-porous structure with an average pore size of several tens of nanometers and a pore wall size of about 10 nanometers; the structural/compositional analyses proved that it is amorphous stannous oxide (SnO). The powder form of the as-anodized specimen was satisfactorily lithiated and delithiated as the anode in a lithium battery. Furthermore, it showed high initial reversible capacity and superior rate performance when compared to previous fabrication attempts. Its excellent electrode performance is probably due to the effective alleviation of strain arising from a cycling-induced large volume change and the short diffusion length of lithium through the nano-structured sample. To further enhance the rate performance, the attempt was made to create porous tin oxide film on copper substrate by anodizing the electrodeposited tin. Nevertheless, the full anodization of tin film on a copper substrate led to the mechanical disintegration of the anodic tin oxide, due most likely to the vigorous gas evolution and the surface oxidation of copper substrate. The adhesion of anodic tin oxide to the substrate, together with the initial reversibility and cycling stability, needs to be further improved for its application to high-power electrode materials in lithium batteries.

• Geotechnical Engineering
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• v.12 no.4
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• pp.47-60
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• 1996

Of the classical theories on lateral earth pressure, the Coulomb's and the Rankine's theories, which have been usually used in practice for design of retaining walls, assumed that the lateral earth pressure was a triangular distribution. However, the experimental results obtained by Terzaghi(1934), Tsagreli(1967), Fang & Ishibashi(1986), etc showed that lateral pressure were not triangular distribution. ' In this study, for rigid walls with inclined backfaces and inclined surfaces backfilled by $C-\phi$ soils, an analytical method of earth pressure distribution has been newly suggested by using the concept of the flat arch. The results calculated by the newly suggested equations were compared with ones by the existed theories. And'the influence factors of the earth pressures by the suggested equations were investigated. As a result, the thrusts obtained by this method agree well with those by the existing theories, except the Rankine's solution. It was showed that the height to the centre of pressure(h) depends mainly upon the inclinations of the backface and the backfilled surface, the angle of internal friction, and the adhesion between the wall and the backfilled soil, instead of 0.33H, where H is the wall height.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.374-378
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• 2010

The effects of $O_2$ plasma pretreatment on the properties of Ga-doped ZnO films on polyimide substrate were studied. GZO films were fabricated by RF magnetron sputtering process. To improve surface energy and adhesion between the polyimide substrate and the GZO film, $O_2$ plasma pretreatment process was used prior to GZO sputtering. As the RF power and the treatment time increased, the crystallinity increased and the contact angle decreased significantly. When the RF power was 100 W and the treatment time was 120 sec, the resistivity of GZO films on the polyimide substrate was $1.90{\times}10^{-3}{\Omega}-cm$.

• Composites Research
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• v.29 no.4
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• pp.203-208
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• 2016

Metal and polymer sandwich composites, which are made of sheet metal sheath and polymer or fiber reinforced plastic core, have been reconsidered as an alternative to sheet metal due to their lightness and multifunctional properties such as damping and sound-proof properties. For the successful applications of these composites, the delamination prediction based on the adhesion strength is important element. In this study, the numerical simulation of the delamination behavior of polymeric adhesive tapes with metallic surfaces was performed using cohesive zone elements and finite element software. The traction-separation law of the cohesive zone element was defined using the fracture energy derived from peel mechanics and experimental results from peel test and implemented in finite element software. The peel test of the polymeric adhesive film against steel surface was simulated and compared with experiments, demonstrating reasonable agreement between simulation and experiment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.6
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• pp.665-674
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• 2015

A TSL (Thin Spray-on Liner) which consists of polymers has a higher initial strength, faster construction time and higher waterproofing performance than the conventional cementitious shotcrete. Main supporting mechanism of TSL is the adhesion and tensile strength which is distinct from the conventional shotcrete. Even though highly in demand due to its outstanding characteristics, TSL is not yet well-known support material. In this study, to evaluate contact behavior of TSL, numerical analysis was performed with comparing result from laboratory tests. From the analysis, cohesive behavior at the contact surface between TSL and rock can be evaluated by using combination of cohesive and the damage model. In addition, results show that the cohesive stiffness controled slope between force and displacement, the fracture energy controled level of force at the contact.