• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.25-28
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• 1962

The colorimetric estimation, by dithiol method, of the solubility of tin dissolved from the container the tin plate in some canned marine foods has been made on 200 cans of sample on the market. Some of them contained more than 150 ppm of Sn concentration were as follows; (1) ca. 50% of squid can, (2)ca. 30% of mackerel can, (3) ca. of saury can, (4) naught of crab, whale, clam(Japanese hard clams), fish meat ball, and Turbo cornutus one. (1) It had the tendency of increasing Sn concentration according to lowering or arising the value of pH. (2) No significant difference in Sn concentration was caused by the variation of the sort of tinning as H-D or E-T. (3) The longer the period of the storage the higher Sn concentration was found, and the concentration more than 150 ppm of Sn was generally found among the cans stored more than twelve months. (4) The concentration of Sn in the liquid was higher than in solid portion, and most of dissolved Sn was distributed in the liquid portion.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.227-236
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• 2018

Objective: The purpose of this study was to investigate the effects of a 12-week combined exercise program on gait parameters in elderly women with osteoarthritis. Method: The subjects of this study were 11 elderly women (age: $67.09{\pm}2.47$, height: $157.35{\pm}4.30cm$, weight: $62.49{\pm}6.36kg$) with knee osteoarthritis. The combined exercise program of this study was divided into aerobic exercise and lower extremity strengthening exercises. The exercises were performed for 60 minutes per session, three times a week, for a total of 12 weeks. The maximum joint moments of the hip, knee, and ankle joints with walking were obtained with 8-3D cameras (MX-T20, Vicon, USA) and 2-force plate (AMTI OR6-7-400, AMTI, USA). SPSS Windows version 23.0 was used for statistical analysis. A paired t-test was used for pre-post comparison. An alpha level of .05 was utilized in all tests. Results: The maximum extension moment was significantly higher in the hip joint after P1 on the X axis. The maximum joint moment of P3 in extension was statistically significantly lower after intervention. On the Z axis, the maximum joint moment was significantly lower after the exercise intervention at P3. There was a statistically significant increase in the extension moment of the left and right knee joints in the X axis after exercise intervention. In the right ankle joint, P1 (plantar flexion moment) showed a statistically significant high moment after exercise intervention. Conclusion: These results suggest that combined exercise, including lower limb and aerobic exercise, may have a positive effect on mobility and walking moments in patients with osteoarthritis of the knee.

• Industry Promotion Research
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• v.4 no.2
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• pp.1-8
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• 2019

This research is a technology for cutting the insulation of the busbar (busbar) installed in the distribution panel or switchboard, the results of the study, first, the cutting unit and frame of the cutting unit including a housing attached to the upper and lower cutters, respectively Busbar coating laser cutting machine is installed on the top, characterized by consisting of a stopper for adjusting the coating cutting distance of the busbar. Second, the frame is installed with the guide bar in the longitudinal direction at the top so as to be located at the rear side end of the table, the post is installed vertically at the front and rear at the upper middle part, respectively, and cut to the table at the outer side of the front post. It is characterized by the formation of holes. Third, the supporter is fixedly installed on the upper part of the guide bar arranged in the frame, and is characterized by consisting of a cylinder and a support plate. The meaning of this study is to prevent the safety accidents of workers, to improve the efficiency of cutting work, and to prevent the occurrence of scratches on the surface of the busbar.

• Corrosion Science and Technology
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• v.21 no.2
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• pp.130-137
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• 2022

In this work, the degradation of high-pressure superheater tubes exposed to the flame of a duct burner in a heat recovery steam generator of a district heating system was evaluated. To assess the deterioration of the used superheater tube, the microstructure, microhardness, and tensile properties were investigated by comparison to an unused tube. The study found that a fin bound at the outer surface of the used tube became fragile only in the location facing the flame. This indicates that the tube was directly exposed to the flame from the duct burner or underwent abnormal overheating. While the unused tube showed a uniform value in hardness and equiaxial grain structure, the used tube revealed a decrease in hardness up to 105 HV and an increase in grain size with a plate-like morphology in the location facing the flame. The coarsening of the grain structure by the flame weakened the mechanical properties of yield strength, tensile strength, and elongation.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.13-19
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• 2005

The radio-sensitivity of pathogens and the effect of irradiation on microbiologican safety and mutagenicity of meat products such as seasoned and cooked beef and ham were investigated. Samples were radiation-sterilized and inoculated at 10/sup 7/ cfu/g with each of the four pathogens including Salmonella typhimurium, Escherichia coli, Staphylcoccus aureus, and Listeria ivanovii. No viable cells of pathogens were observed in the sample irradiated with 3 kGy. The D/sub 10/ value of inoculated pathogens in seasoned and cooked beef and ham were 0.24∼0.48 and 0.39∼0.45, respectively. Results of Ames test performed with non-irradiated and irradiated seasoned and cooked beef and ham were both negative at the level of 625, 1,250, 2,500, 50,000, and! 10,000 ㎍ sample/plate, respectively. Results indicate that low dose (2∼3 kGy) irradiation is effective to ensure safety for seasoned and cooked beef and ham with toxicological wholesomeness.

• Journal of Environmental Health Sciences
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• v.40 no.3
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• pp.255-263
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• 2014

Objectives: This study evaluated the fungicidal efficacy of a fumigant containing 20% ortho-phenylphenol against Trichophytone mentagrophytes (T. mentagrophytes), Candida albicans (C. albicans) and Aspergillus niger (A. niger). Methods: Five replicates of each carrier were contaminated by depositing 0.05 mL of each fungal suspension. After drying, two carriers without exposure to the fumigant and three carriers with exposure to the fumigant were left in a sealed room ($25m^3$) at $21{\pm}0.5^{\circ}C$ and $60{\pm}10%$ relative humidity for 15 hours. Immediately after removal from the test room, each carrier was transferred into recovery diluent and suspended, diluted and inoculated. After incubation, the numbers of each colony were counted, and the parameter values (N, T, d) were calculated. Results: The working culture suspension number (N value) of T. mentagrophytes, C. albicans and A. niger were $1.0{\times}10^8$, $1.2{\times}10^8$ and $5.7{\times}10^7CFU/mL$, respectively. All the colony numbers on the carriers exposed to the fumigant (n1, n2, n3) were higher than 0.5N1 (the number of fungal test suspensions by pour plate method), 0.5N2 (the number of fungal test suspensions by filter membrane method) and 0.5N1, respectively. In addition, all mean numbers of test strains recovered on the control-carriers (T value) were over $10^6CFU/mL$. For the fungicidal effect of the fumigant, all numbers of fungal reductions after exposure of the fumigant (d value) were 4 logCFU/mL. Conclusions: The present study showed that fumigant containing 20% ortho-phenylphenol has effective fungicidal activity against T. mentagrophytes, C. albicans and A. niger.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.131-134
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• 2011

We propose a spheroid chip that uses removable cell trapping barriers and that is capable of forming and extracting multicellular spheroids. By using a conventional well plate and flask, it is difficult to form small-sized spheroids, which resemble avascular 3D cell-cell interaction. It was difficult to extract spheroids using conventional microchips and fixed cell trapping barriers. The proposed chip, however, facilitates both formation and extraction of spheroids by using removable cell trapping barriers formed by membrane deflection. The cell trapping barriers, formed at the membrane pressure of 50 kPa, hold the cells in the trapping region at a cell inlet pressure of 145.155 Pa. After incubation for 24 h, the trapped cells form uniform spheroids. We successfully extract the spheroids at a cell inlet pressure of 5 kPa after removing the membrane pressure. The extracted spheroids have a diameter of $197.2{\pm}11.7Bm$ with a viability of $80.3{\pm}7.7%$. Using the proposed chip, uniform spheroids can be formed and these spheroids can be safely extracted for carrying out the post-processing of spheroids.

• The korean journal of orthodontics
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• v.25 no.6 s.53
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• pp.715-722
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• 1995

Orthodontic tooth movement in response to orthodontic force results from actions of osteoclasts and osteeoblasts in the cell level. Convincing evidence has now been provided to support the view that osteoclasts are derived from mononuclear cells that originate in the bone marrow or other hematopoietic organs and they migrate to the bones via vascular routes. Nitric oxide(NO), which accounts for the biological properties of endothelium-derived relaxing factor(EDRF), is the endogenous stimulator of soluble guanylate cylase. The discovery of the formation of nitric oxide(NO) from L-arginine in mammalian tissues and its biological roles has, in the last 7 years, thrown new light onto many areas of research. Data from experiments in vitro showed that N-metyl-L-arginine(L-NMA) and L-nitro-L- arginine(L-NAME) are competitive inhibitors of nitric oxide synthase. This study suggest that the multinucleated cells in our culture have characteristics of osteoclasts and that the potential bone cell activity of nitric oxide in vitro may be mediated in part by stimulation of marrow mononuclear cells to form osteoclast-like cells. Bone marrow cells were obtaineed from tibia of 19-days old chick embryo. After sacrifice, tibia was quickly dissected and the bone were then split to expose the medullary bone. The cells were attached for 4 hours and the nonadherent cells were collected. Marrow cells weere cultured in 96-well plate in medium 199. To examine the number of TRAP-positive multinucleated cells(MNCs), $10^{-8}\;M\;Vit=D_3$ and various concentration of L-NMA and L-NAME weere added at the beginning of cultures and with each medium change. After 7 days of culture. tartrate-resistant acid phosphatase(TRAP) staining was performed for microscopic evaluation. Cells haying more than three nuclei per cell were counted as MNCs. The obsrved results were as follows;1. 1,25-dihydroxyvitamine $D_3$ stimulated the osteoclast-like multinucleated cells in cultures of chick embryo bone marrow. 2. Nitric oxide synthase inhibitors(NOSI ; N-NMA, N-NAME) stimulated the osteoclast-like cells in cultures of chick embry bone marrow. 3. 1,25-dihydroxyvitamine$D_3$ and nitric oxide synthase inhibitors did not appear to have additive effect on the generation of TRAP-positive MNCs. These results suggest that nitric oxide synthase inhibitors may stimulate the osteoclast-like multinucleated cell formation and fusion in cultures of chick bone marrow.

• Composites Research
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• v.13 no.2
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• pp.30-39
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• 2000

It is difficult for civil engineer to apply composite materials of laminated type to structure for civil construction because of complicated theory although those have much merit. A simple method by which one can predict "exact" values of the natural frequency of vibration of laminated plates is presented. Many laminates with particular orientations have negligible values of $B_{16}$ and $B_{26}$ as the number of plies increases. Such laminates, with $D_{16}$ = $D_{26}$ ->0 can be solved by the same equation as for the special orthotropic laminates(1991,1995). If the quasi-isotrpic constants are used, It is possible to simplify analysis procedure since the equations for isotropic plates can be used. Use of some coefficients can produce "exact" values for laminates with such configuration. This coefficient, in fact, represents the effect of the anisotropy of the laminate. D. H. Kim proposed to use a correction factor, he developed, to produce "exact" solution out of the approximate solution obtained by using the quasi-isotropic constants(1995). In this paper, the fiber orienation studied is [$\alpha$/$\beta$/$\beta$/$\gamma$/$\alpha$/$\alpha$/$\beta$]r, with $\alpha$=-$\beta$, and $\gamma$${\gamma}$=$0^{\circ}$ or $90^{\circ}$ and the above-mentioned method is used to obtain the natural frequencies of plates with such orientations, and detailed result is presented for the use of engineers.nted for the use of engineers.

• Bulletin of the Korean Chemical Society
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• v.18 no.8
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• pp.831-840
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• 1997

Core/shell structured composite metal oxides of Fe2O3/MgO were prepared by thermal decomposition of Fe(acac)3 adsorbed on the surface of MgO cores. The morphology of the composites conformed to that of the MgO used as the cores. Broad powder X-ray diffraction peaks shifted toward larger d, large BET surface area (∼350 m2/g), and the size of crystalline domains in nano range (4 nm), all corroborate to the nanocrystallinity of the Fe2O3/MgO composite which was prepared by using nanocrystalline MgO as the core. By use of microcrystalline MgO as the core, microcrystalline Fe2O3/MgO composite was prepared, and it had small BET surface area of less than 35 m2/g. AFM measurements on nanocrystalline Fe2O3/MgO showed a collection of spherical aggregates (∼80 nm dia) with a very rough surface. On the contrary, microcrystalline Fe2O3/MgO was a collection of plate-like flat crystallites with a smooth surface. The nitrogen adsorption-desorption behavior indicated that microcrystalline Fe2O3/MgO was nonporous, whereas nanocrystalline Fe2O3/MgO was mesoporous. Bimodal distribution of the pore size became unimodal as the layer of Fe2O3 was applied to nanocrystalline MgO. The macropores in a wide distribution which the nanocrystalline MgO had were absent in the nanocrystalline Fe2O3/MgO. The decomposition of CCl4 was largily enhanced by the overlayer of Fe2O3 on nanocrystalline MgO making the reaction between nanocrystalline Fe2O3/MgO and CCl4 be nearly stoichiometric. The reaction products were environmentally benign MgCl2 and CO2. Such an enhancement was not attainable with the microcrystalline samples. Even for the nanocrystalline MgO, the enhancement was not attained, if not with the Fe2O3 layer. Without the layer of Fe2O3, it was observed that the nanocrystalline domain of the MgO transformed into microcrystalline one as the decomposition of CCl4 proceeded on its surface. It appeared that the layer of Fe2O3 on the particles of nanocrystalline Fe2O3/MgO blocked the transformation of the nanocrystalline domain into microcrystalline one. Therefore, in order to attain stoichiometric reaction between CCl4 and Fe2O3/MgO core/shell structured composite metal oxide, the morphology of the core MgO has to be nanocrystalline, and also the nanocrystalline domains has to be sustained until the core was exhausted into MgCl2.