• Journal of the Korean Society for Railway
• /
• v.15 no.5
• /
• pp.485-497
• /
• 2012

Recently, with increasing social interests on noise and vibration induced by railway traffic, the application of floating slab track that can efficiently reduce the railway vibration is increasing. In this study, to more accurately understand the dynamic behavior of the floating slab track, a laboratory mock-up test has been performed, and the static and dynamic behaviors at frequency range near the system resonance frequency were explored. Based on the test results, the design of the floating slab track and the structural analysis model used in the design have been verified. The analytic and test results demonstrate that the dominant frequency of the floating slab track occurs at the frequencies between vertical rigid body mode natural frequency and bending mode natural frequency, and the dominant deformation mode is close to the bending mode. This suggests that in the design of the floating slab track, the bending rigidity of the slab and the boundary conditions at slab joints and slab ends should be taken into consideration. Also, the analytic results by the two-dimensional finite element analysis model using Kelvin-Voigt model, such as static and dynamic deflections and force transmissibility, are found in good agreement with the test results, and thus the model used in this study has shown the reliability suitable to be utilized in the design of the floating slab track.

• Journal of the Korean Chemical Society
• /
• v.27 no.5
• /
• pp.353-360
• /
• 1983

The adsorption behavior of 8-hydroxyquinoline (8HQ) on Amberlite XAD-4 and-7 resins was investigated by measuring its distribution coefficients under various experimental conditions, such as shaking time, pH and concentration of methanol in the medium. The application of 8HQ-impregnated-XAD resins for the absorption and separation of metal ions was studied. The maximum adsorption of 8HQ on XAD resins was observed in the 30% methanol solution having pH range from 6.0 to 9.0. The impregnation capacities of XAD resins for 8HQ were 3.81${\times}$10-2mmol, 8HQ/g, XAD-4 resins and 2.60${\times}$10-2mmol, 8HQ/g, XAD-7 resin, respectively. The 8HQ-impregnated-XAD resins were stable in pH range from 6.0 to 10.0 and the amount of 8HQ leached from XAD-4 resin by eluting with hydrochloric acid(above 5M) was negligible. The optimum pH range for the adsorption of metal ions on 8HQ-impregnated XAD resin was also 6.0 to 10.0, and the adsorption mole ratio of metal ion to 8HQ were 1 : 2 for Cu(II), Cd(II) and Ni(II), and 1 : 3 for Fe(III) at the above pH range. It was found that the absorbed metal ions on 8HQ-impregnated-XAD resins were recovered quantitatively with 5M HCl and 8HQ-impregnated-XAD-4 resin could be reusable over 5 times without decrease in its impregnation capacity.

• Clean Technology
• /
• v.19 no.4
• /
• pp.388-392
• /
• 2013

Iindium-tin-oxide (ITO) material was had to use in display application as transparent electrode. However it would be problems comes up, the depletion of indium, tin and energy consumption of production process. Therefore recently trend was demanded alternative ITO material and recycling/reused ITO. In this conditions, the environmental impact have to express correct value about recycling/reused ITO process. The life cycle assessment was valuable method in this process. Thus first step was carried out separating in/out put (material) sources and then, exactive data base (DB) was applied. The result of environment impact was calculated by affect categories and recycling rate was set to 34% (This value was measured in previous project). The rate (g) of ITO material was calculated by chemical equivalent. In result, environmental impact were revealed acidification potential and abiotic depletion and if do not recycle/reuse ITO, $ 476 per 1 ton waste in land.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.33 no.5
• /
• pp.339-349
• /
• 2020

Double-leaf blast-resistant doors consisting of steel box and slab are application-specific structures installed at the entrances of protective facilities. In these structural systems, certain spacing is provided between the door and wall. However, variation in the boundary condition and structural behavior due to this spacing are not properly considered in the explosion analysis and design. In this study, the structural response and failure behavior based on two variables such as the spacing and blast pressure were analyzed using the finite element method. The results revealed that the two variables affected the overall structural behavior such as the maximum and permanent deflections. The degree of contact due to collision between the door and wall and the impact force applied to the door varied according to the spacing. Hence, the shear-failure behavior of the concrete slab was affected by this impact force. Doors with spacing of less than 10 mm were vulnerable to shear failure, and the case of approximately 15-mm spacing was more reasonable for increasing the flexural performance. For further study, tests and numerical research on the structural behavior are needed by considering other variables such as specifications of the structural members and details of the slab shear design.

• The Journal of Dong Guk Oriental Medicine
• /
• v.8 no.2
• /
• pp.47-67
• /
• 2000

The purpose of this study is to assess the usefulness of thermography in patients with musculoskeletal disease. Thermography is noninvasive, easy to reading, objective and physiologic instrument by measuring and imaging infrared energy emitted from skin surface. Thermography can show the skin temperature changes in various conditions of the body with musculoskeletal disease. This literature review was done for the usefulness of thermography in diagnosing musculoskeletal disease. In conclusion, thermography was adapted in radiculopathy, MPS, peripheral neuropathy, RSD, Raynaud's phenomen, TMJ dysfunction, etc. It was useful as a secondary diagnostic method in those diseases, also possible as a primary diagnostic method in RSD, Raynaud's phenomen. And, it might be reliable tool for estimating disease procedure and consequence after treatment. But, the objectivity of the reading and the development of the operating method are required for further adaptation in musculoskeletal disease.

• The Korean Journal of Mycology
• /
• v.42 no.3
• /
• pp.225-230
• /
• 2014

Sclerotinia sclerotiorum, a plant pathogenic fungus, can cause serious yield and quality losses in the winter lettuce field. For biological control of S. sclerotiorum, soil-born microorganisms that inhibit the mycelia growth of S. sclerotiorum and Fusarium oxysporum were isolated from diseased soil. Among the isolates, bacterial isolate, GG95, which was identified as Bacillus subtilis according to the morphological, physiological characteristics and by 16S rRNA similarity, showed the highest level of inhibitory activity. The growth conditions for B. subtilis GG95 were optimized in TSB media (pH 7) by culturing at $28^{\circ}C$ for 24 hrs. Maltose or fructose and peptone were selected as the best carbon and nitrogen sources, respectively. Greenhouse experiment was performed to test effectiveness of B. subtilis GG95 in the control sclerotinia rot. Drench application ($1{\times}10^8cfu/mL$, 3 times) of the bacterial culture broth to lettuce showed an effectiveness value of 88%, suggesting that B. subtilis GG95 would be a promising biocontrol agent for control of sclerotinia rot.

• 한국균학회소식:학술대회논문집
• /
• 2018.05a
• /
• pp.44-44
• /
• 2018

Fusarium head blight (FHB) caused by infection with Fusarium graminearum leads to enormous losses to crop growers, and may contaminate grains with a number of Fusarium mycotoxins that pose serious risks to human and animal health. Antagonistic bacteria that are used to prevent FHB offer attractive alternatives or supplements to synthetic fungicides for controlling FHB without the negative effects of chemical management. Out of 500 bacterial strains isolated from soil, Bacillus amyloliquefaciens JCK-12 showed strong antifungal activity and was considered a potential source for control strategies to reduce FHB. B. amyloliquefaciens JCK-12 produces several cyclic lipopeptides (CLPs) including iturin A, fengycin, and surfactin. Iturin A inhibits spore germination of F. graminearum. Fengycin or surfactin alone did not display any inhibitory activity against spore germination at concentrations less than 30 ug/ml, but a mixture of iturin A, fengycin, and surfactin showed a remarkable synergistic inhibitory effect on F. graminearum spore germination. The fermentation broth and formulation of B. amyloliquefaciens JCK-12 strain reduced the disease incidence of FHB in wheat. Furthermore, co-application of B. amyloliquefaciens JCK-12 and chemical fungicides resulted in synergistic in vitro antifungal effects and significant disease control efficacy against FHB under greenhouse and field conditions, suggesting that B. amyloliquefaciens JCK-12 has a strong chemosensitizing effect. The synergistic antifungal effect of B. amyloliquefaciens JCK-12 and chemical fungicides in combination may result from the cell wall damage and altered cell membrane permeability in the phytopathogenic fungi caused by the CLP mixtures and subsequent increased sensitivity of F. graminearum to fungicides. In addition, B. amyloliquefaciens JCK-12 showed the potential to reduce trichothecenes mycotoxin production. The results of this study indicate that B. amyloliquefaciens JCK-12 could be used as an available biocontrol agent or as a chemosensitizer to chemical fungicides for controlling FHB disease and as a strategy for preventing the contamination of harvested crops with mycotoxins.

• Polymer(Korea)
• /
• v.31 no.3
• /
• pp.215-220
• /
• 2007

The control of the surface energy by electrohydrodynamic force provides electrospraying with various potential advantages such as simple particle size control, mono-dispersity, high recovery, and mild processing conditions. The advantages are quite helpful to improve the stability of protein drug and control its release. Herein, the nano-encapsulation of protein drugs using electrospraying was investigated. Albumin as a model protein was processed using uniaxial and co-axial electrospraying, and chitosan, polycaporlactone (PCL), and poly (ethylene glycol) (PEG) were used as encapsulation materials. The major processing parameters such as the conductivity of spraying liquids, flow rate, the distance of electrical potential gradient, etc were measured to obtain the maximum efficiency. In the chitosan systems, mean particles size decreases as flow rate and the distance between nozzle and the collecting part decreases. In the uniaxial technique of the PCL systems, mean particles size decreases as flow rate decreases. In the coaxial technique of the PCL systems, it was found that the particles size gets larger under the application of the higher ratio of inner-to-outer liquid flow rates. The primary particles formed out of an electrospraying nozzle showed narrow particle size distribution, but once they arrived to the collecting part, aggregation behavior was observed obviously. Efficient nano-encapsulation of albumin with PCL, PEG, and chitosan was conveniently achieved using electrospraying at above 12 kV.

• Korean Journal of Weed Science
• /
• v.15 no.3
• /
• pp.214-223
• /
• 1995

Tolerant corn cultivars to bentazon were selected and tolerance mechanism of corn cultivars to bentazon was studied by determining bentazon 6-hydroxylase(B6H) activity which was known to detoxify bentazon to 6-hydroxy bentazon at induced enzyme conditions with treatments of 1,8-naphthalic anhydride, ethanol and phenobarbital. Tolerant cultivars to bentazon were selected by growth response of corn by foliar application of bentazon to corn cultivars. Kwanganok, GA 209, IK 2, DB 544, and Suwon 19 were tolerant to bentazon, but KSS 3, KSS 4, KS 5, and Danok 2 were susceptible. Pretreating corn seeds with 1,8-naphthalic anhydride increased B6H activity at all cultivars, but the tendencies were more remarkable at Suwon 19 and GA 209, tolerant cultivars, than at Danok 2 and KS 5, susceptible cultivars. Treating corn shoots with ethanol increased B6H activity at Suwon 19 and GA 209. B6H activity was enhanced by treatments of ethanol at 1.0 or 2.5%, but decreased at ethanol 2.5 or 5.0% at Danok 2 and KS 5. Treating corn shoots with phenobarbital increased B6H activity at Suwon 19, GA 209, Danok 2, and KS 5 by treatments of phenobarbital at 2.0mM, but decreased at 4.0 or 8.0mM at all cultivars. Therefore, the tolerant mechanism of corn cultivars to bentazon may be explained partially by the activity of bentazon 6-hydroxylase which detoxifies bentazon to 6-hydroxy bentazon.

• Korean Journal of Materials Research
• /
• v.8 no.12
• /
• pp.1146-1151
• /
• 1998

The crystallization behaviour of perovskite $PbTiO_3$ for the samples heat- treated at various temperatures for various times in the $PbO-TiO_2-A1_2O_3-SiO_2$, glass system has been investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Higher crystallinity obtained in the sample heat-treated at higher temperature for longer time. With increasing heat-treatment time, dielectric constant of the samples heat-treated at $610^{\circ}C$ and $650^{\circ}C$ increased, but that of the sample heat- treated at $800^{\circ}C$ decreased. Loss tangent of the heat-treated samples was not much influenced by heat-treatment conditions. Piezodielectric charge constant was approximately $1.0\times10^{-12}~8.0$\times$10^{-12}C/N$ in the samples heat-treated at $800^{\circ}C$ for 1h, 2h, and 8h.