• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.96-101
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• 2015

In the previous study, we investigated the physical properties of new organic fillers made from major agricultural byproducts, including rice husks, peanut husks and garlic stems, and we estimated that rice husk was the best candidate for use as new organic fillers in paperboard. In this study, an organic filler prototype was produced with rice husk and the mill trials were carried out in a white liner chipboard (duplexboard) mill. The rice husk organic filler was added to the middle ply of SC $350g/m^2$ to determine the optimal conditions for the manufacture of rice husk organic fillers. The mill trials were performed three times and the bulk improvement and drying energy reduction were measured to identify the functionality of the rice husk organic filler compared to that of the commercial wood powder. In the first mill trial, the test failed because the surface roughness of the duplexboard had deteriorated after the rice husk organic filler was added to the OCC stock. As all of the particles remaining on the 60 mesh sieves were removed and the particle size was decreased by increasing the length of the grinding process, the surface roughness of the duplexboard did not be deteriorated in the second mill trial. However, the bulk improvement and drying energy reduction were not observed. In the final mill trial, as the particle size of the rice husk organic filler was controlled by increasing the portion of particles passing through the 60 mesh sieves and remaining 100 mesh sieves, higher bulk improvement and drying energy reduction were acquired compared to the commercial wood powder.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.750-759
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• 2016

The $MnO_2$ electrodeposited on the surface of the carbon nanofiber mats ($MnO_2$-LCNFM) were prepared from electrospun lignin-g-PAN copolymer via heat treatments and subsequent $MnO_2$ electrodeposition method. The resulting $MnO_2$-LCNFM was evaluateed for its potential use in a supercapicitor electrode. The increase of $MnO_2$ electric deposition time was revealed to increase diameter of carbon nanofibers as well as $MnO_2$ content on the surface of carbon nanofiber mats as confirmed by scanning electon microscope (SEM) analysis. The electrochemical properties of $MnO_2$-LCNFM electrodes are evaluated through cyclic voltammetry test. It was shown that $MnO_2$-LCNFM electrode exhibited good electrochemical performance with specific capacitance of $168.0mF{\cdot}cm^{-2}$. The $MnO_2$-LCNFM supercapacitor successfully fabricated using the gel electrolyte ($H_3PO_4$/Polyvinyl alcohol) showed to have the capacitance efficiency of ~90%, and stable behavior during 1,000 charging/discharging cycles.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.117-124
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• 2003

Reinforced concrete structures under sever conditions such as marine structures, bridges and structures constructed with aggregates(dredged from sea), can be deteriorated from corrosion of the reinforcing bars. The purpose of this study is to evaluate the anti-corrosive performance of coated steel using polymer cement slurry. Polymer cement slurry with various polymer dispersions and corrosion inhibiting agent were coated to the surface of bars, and tested for accelerated corrosion tests. Tests include immersion in NaCl 10% solution, chloride ion spray, autoclave cure, autoclave cure after carbonation, penetration of NaCl 10 % solution, carbonation after penetration of NaCl 10% solution. Test results, show that the anti-corrosive performace is considerably improved by using polymer cement slurry at surface of steel. And this trend is marked by adding of corrosion inhibiting agent. This difference of the anti-corrosive properties is hardly recognized according to types of polymer dispersions. The coated steel using polymer cement slurry will be improved to a great extent compared to those of plain steel when increasing content of chloride ion in cement concrete.

• Restorative Dentistry and Endodontics
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• v.27 no.4
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• pp.403-410
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• 2002

Several ways of curing are being tried to improve material's properties and reduce marginal gap. However, all are considering about the pattern of light intensity. It was noted from the preliminary study the change of light wavelength from filter changing may give an impact on material's property and microleakage. The object of this study was to verify the effect of filters with various wavelength width on the microhardness and microleakage of composite resin ; hybrid type of DenFil and submicron hybrid type of Esthet X. Composite resins were cured using 3 kinds of filter; narrow-banded(465-475 nm), mid-banded(430-470 nm), wide-banded(400-500 nm). After the estimation of microhardness. degree of dye penetration and the maximum gap from SEM evaluation were done between 4 groups that showed no difference in microhardness value of the lower surface . The results were as follows : 1 Adequate microhardness could not be gained with a narrow-banded filter irrespective of curing time. At the upper surface, DenFil should be polymerized with middle or wide-banded filter for 20 seconds at least, while Esthet X be col$.$ed with middle or wide-banded filter for 30 seconds at least to get simitar hardness value to control group. 2. There was little dye penetration in enamel margin, but all dentin margins skewed much more dye penetration irrespective of curing conditions. Although there was no statistical difference, groups cured with mid-banded filter for 40 seconds and with wide-width filter for 20 seconds showed relatively less dye penetration. 3. It was revealed from the SEM examination that group cured with wide-banded filter had the smallest gap without statistical significance. Spearman's rho test showed that the correlation between the results of dye penetration and SEM examination was very low. From these results, it could be concluded that curing with wide-width filter would be better than the other techniques, even though the curing technique using mid-width filter seems to have its own unique advantage.

• Journal of Sensor Science and Technology
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• v.11 no.6
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• pp.342-349
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• 2002

New formation technique of metal oxide sensing film was proposed m this paper. Silicon wafer with Pt electrodes was used as a substrate for depositing metal Sn film. Metal Sn was deposited in the state of not continuous film but only island state. The samples were prepared to obtain the optimal condition of metal Sn deposition. The resistances of deposited Sn onto Pt electrodes amounted to $1\;k{\Omega}$, $5\;k{\Omega}$, $10\;k{\Omega}$ and $50\;k{\Omega}$, respectively. Also The sample with $1,500\;{\AA}$ thickness of Sn was prepared m order to compare sensing properties between conventional type and proposing type. After deposition of metal Sn, $SnO_2$ was formed by thermal oxidation method for 3 hrs. in $O_2$ ambient at $700^{\circ}C$. Surface morphology, crystal structure and surface roughness of oxidized-sensing film were examined by SEM, XRD, and AFM, respectively. From the results of these analyses, the optimal deposition condition of Sn was that the Pt electrode resistance became $10\;k{\Omega}(300\;{\AA})$. Also, the sensing characteristics of fabricated sensing film for various concentrations of butane, propane and carbon monoxide gases were measured at he operating temperatures of $250^{\circ}C$, $300^{\circ}C$ and $350^{\circ}C$, respectively. Although catalyst as not added to the sensing film, it has exhibited the high sensitivity to all the test gases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.42-50
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• 2016

Overlay welding affects the chemical components and weld hardness by dilution of the lamination layer thickness, which determines the surface properties. This study experimentally investigates different numbers of layers for overlay welding monel materials, which are anti-corrosion materials. The Fe content, weldability of the base metal and monel materials, hardness, and surface flatness were examined. Each evaluation was carried out after overlay welding with three layers on the base material and pipe base material of the plate. The Fe content was evaluated by analyzing the constituents of each layer. The Fe content was satisfactory in the three layers. The weldability of the laminate specimens was evaluated by a bending test. The hardness and bead flatness of the laminate specimens were evaluated by micro Vickers and 3D measurements. The hardness was highest in the heat-affected zone with one layer, and it decreased with increasing lamination. In the case of bead flatness, there is a sharp difference in the deviation with increasing numbers of laminations, which should be considered carefully.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.53-63
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• 1992

M/BM -series catalysts, $MoO_3$ supported on ${\alpha}-Bi_2Mo_3O_{12}$ were also prepared by impregnation method. BM/M-series catalysts, ${\alpha}-Bi_2Mo_3O_{12}$ supported on $MoO_3$ were also prepared by coprecipitation. Structure and catalytic properties of the two phase catalysts were studied by means of using nitrogen adsorption, X-ray diffraction, and scanning electron microscopy. The reaction test for the selective oxidation of propylene to acrolein over Bi-molybdate catalysts was studied using a fixed-bed reactor system. In M/BM-series catalysts, $MoO_3$ was dispersed on ${\alpha}-Bi_2Mo_3O_{12}$, and the crystal structure of ${\alpha}-Bi_2Mo_3O_{12}$ remains unchanged by the presence of excess $MoO_3$. However the surface morphology and bulk structure of BM/M-series catalysts were altered probably because the precipitated $Bi(OH)_3$ reacted with $MoO_3$ during the calcination to form ${\alpha}-Bi_2Mo_3O_{12}$ phase. The results of propylene oxidation on both series catalysts showed that the reaction took place over the surface of ${\alpha}-Bi_2Mo_3O_{12}$ particle and the role of excess $MoO_3$ was to supply oxygen to ${\alpha}-Bi_2Mo_3O_{12}$. These increasing effects on activity were also observed in the mechanical mixtures of ${\alpha}-Bi_2Mo_3O_{12}$ and $MoO_3$.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.349-357
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• 2011

Purpose: In this study, for the reasons of observing the changes when using bonding agent with Ni-Cr alloy and Co-Cr alloy and using VM13 and Vintage MP ceramic which have the disparity in coefficient of thermal expansion, it is carried out to evaluate the characteristics of the bonding agent through the analysis of the interface between metal and ceramic and the analysis of bond strength by variable. Methods: The surface treatment was performed on the two kinds of alloy(Ni-Cr alloy and Co-Cr alloy) specimens, which were sandblasted and were treated with bonder application. The metal-ceramic interfaces were analyzed with EPMA in order to ionic diffusion, and the shear test was performed. Results: As a result of observation of metal-ceramic interfacial properties, it was observed that Cr atoms were spread from the alloy body to the ceramic floor in the specimen of Group B. It was also seen that Cr, W atoms were spread from the alloy body to the ceramic floor in the specimen of Group S. In consequence of observing Shear bond strength, it was calculated that the specimen of BSV was 27.75(${\pm}11.21$)MPa, BSM was 27.02(${\pm}5.23$)MPa, BCV was 30.20(${\pm}5.99$)MPa, BCM was 27.94(${\pm}10.76$)MPa, SSV was 20.83(${\pm}2.58$)MPa, SSM was 23.98(${\pm}3.94$)MPa, SCV was 32.32(${\pm}4.68$)MPa, and SCM was 34.54(${\pm}10.63$)MPa. Conclusion: In the metal-ceramic interface of Bellabond plus sample group, diffusion of Cr atoms was incurred and diffusion of C Cr atoms and W atoms in the sample group of $Starloy{(R)}\;C$ was observed. Using bonding agent showed the higher bond strength than using the sand blasting treatment. In the Bellabond plus alloys, the specimen group with the use of binding materials showed higher shear bond strength, but didn't show statistically significant differences (p>0.05). In the $Starloy{(R)}\;C$ alloys, the specimen group with the use of binding materials showed higher shear bond strength and statistically significant differences(p<0.05). In terms of VM13 ceramic, it was in the Bellabond plus alloys that the high shear bond strength was showed, but there's no statistically significant differences(p>0.05). In terms of Vintage MP ceramic, it was in the $Starloy{(R)}\;C$ alloys that the high shear bond strength was showed and statistically significant differences(p<0.05). Metal-ceramic to fracture of the shear strength measurements and an analysis of all aspects of military usage fracture of the composite, respectively.

• Journal of the Korean Wood Science and Technology
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• v.18 no.4
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• pp.65-78
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• 1990

For the purpose of Improving the sounding boards for the conventional GAYAKUM, I was making approximately 202 specimens of radial board, 371 specimens of tangential board by cutting along the grain and the part of stem and 31 specimens of the disjointed traditional GAYAKUM made in Paulownia coreana. And it was conducted to measure specific gravity, dynamic Young's modulus, internal friction, resonant frequency, velosity of sound and width of annual ring by the method of the frexural vibration in a free-free bar in the audio frequency range. And it confirmed the juvenile wood by measuring wood fiber length of specimens. It was also conducted to investigate dynamic properties and moisture absorption by various heat-treatment and to test dynamic Young's modulus and internal friction for the disjointed conventional GAYAKUM. The results obtained were summarized as follow: 1. The Juvenile wood is located within about 7 annual rings from the pith in Paulownia coreana. 2. As increased with the specific gravity, the dynamic Young's modulus had more and more increased, but the internal friction had slightly decreased. 3. I think that radial board would be good for sounding board wood. because radial board is higher than tangential board in dynamic Young's mudulus and internal friction is lower than tangential board. 4. The value of mean dynamic Young's modulus on the conventional GAYAKUM, radial board and tangential board of 604 samples is $0.4283\pm0.037(\times10^{11}dyne/cm^2)$, $0.4316\pm(\times10^{11}dyne/cm^2)$ and $0.4234\pm0.112(\times10^{11}dyne/cm^2)$ respectively. The value of the radial board showed little higher than that of conventional GAYAKUM, but It had a similar tendency between conventional GAYAKUM and tangential board. 5. The annual ring width by four aspect is more narrow in north and west than that of others. 6. The values of specific gravity and dynamic Young's modulus in the mature wood showed higher than those of juvenile wood. 7. As the grain angle in the butt wood more increased to bark from pith, the dynamic Young's modulus were low. Then it was not good for sounding board. 8. It appeared that the heat-treatment for sounding board wood had a more effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature. 9. As increased with the temperature, the rate of moisture absorption of heat-treatment wood had decreased. In conclusion, I thought that the sounding board wood for GAYAKUM would had the most effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature using the radial board of mature wood.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.707-716
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• 2010

Germinated brown rice is a useful material that contains natural nutrients and biologically active substances. This study was conducted to develop a optimal composite recipe for functional germinated brown rice cookie with added spinach (spinacia oleracea L) powder and with high preference in all age groups. The experimental design utilized herein was based on the Central composite design methodology of response surface, which included 16 experimental points, including 2 replicates for spinach, sugar, and butter. The physical, mechanical, and sensory properties of the test were measured, and these values were applied to the mathematical models. A canonical form and perturbation plot showed the influence of each ingredient on the mixed final product. The results of spread ratio decreased significantly with increases in spinach powder, sugar, and butter(p<0.01). L value shows that lightness decreased significantly with an increase in sugar(p<0.05), but the a and b values were not significant. Sensory evaluation found significant values for color(p<0.05), flavor(p<0.05), texture(p<0.05) and overall quality(p<0.05) in the predicted model. The optimum formulation by the numerical and graphical methods was calculated as follows: spinach powder 3 g, sugar 35.5 g butter 54.4 g.