• Korean Journal of Rural Living Science
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• v.8 no.2
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• pp.83-91
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• 1997

In this study, the dyeability of natural dye extracted from chesnut shell was investigated in order to explore the using of discarded chesnut shell in natural dyeing. Dyeing experiments were done in various dyeing conditions which were different in dyeing temperature, concentration of dyebath, dyeing time, repitition of dyeing. pH of dyebath and mordant with 3 kinds of experimental fabrics silk, nylon and cotton. Color and color difference ($\Delta$ E) of every dyed fabrics were measured and color fastness to drycleaning, washing, perspiration and light were measured. The results were as follows ; 1. The dyebath became thicker with time and temperature of extraction and the characteristics of dyebath prepared chesnut shell 1g : distilled water 30㏄ after 3 hrs-boiling were 32,400ppm and 3.7pH. 2. The dyeabilities of silk and nylon fabrics were good and color difference was increased with dyeing temperature, concentration of dyebath, dyeing time, number of repitition and acidity of dyebath. But the dyeability of cotton was very poor compared to silk and nylon. 3. Without the treatment of mordant, the dyeability of silk was little lower than that of nylon, but after the treatment of mordants it became higher than nylon. After the treatment of mordant Cu and Fe, the dyeability of cotton was increased although the natural dye from the chesnut shell was hardly absorved in cotton without mordant. 4. On the whole, the colorfastness of dyed silk and nylon were very good except the colorfastness to washing in silk and the colorfastness to light in nylon.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.107-114
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• 2015

Large spatial structures can not easily predict the dynamic behavior due to the lack of construction and design practices. The spatial structures are generally analyzed through the numerical simulation and experimental test in order to investigate the seismic response of large spatial structures. In the case of analysis for seismic response of large spatial structure, the many studies by the numerical analysis was carried out, researches by the shaking table test are very rare. In this study, a shaking table test of a small-scale arch structure was conducted and the dynamic characteristics of arch structure are analyzed. And the dynamic characteristics of arch structures are investigated according to the various column cross-section and length. It is found that the natural vibration periods of the small-scaled arch structure that have large column stiffness are very similar to the natural vibration period of the non-column arch structure. And in case of arch structure with large column stiffness, primary natural frequency period by numerical analysis is very similar to the primary natural frequency period of by shaking table test. These are because the dynamic characteristics of the roof structure are affected by the column stiffness of the spatial structure.

• Korean Journal of Pharmacognosy
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• v.16 no.3
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• pp.129-135
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• 1985

In order to search for potential antidotes for T-2 toxin poisoning, seven Chinese herbal drug extracts and five natural constituents were tested on mice intoxicated with T-2 toxin. When extracts of Panax ginseng and Atractylodes japonica (500 mg/kg) were administered p.o. once 3 hrs before and once 1 hr after T-2 toxin treatment, a 30% complete survival rate was noted. In case of Paeonia albiflora var. typica, a 30% complete survival rate was also produced at a dose of 250 mg/kg. Other extracts, Glycyrrhiza uralensis, Scutellaria baicalensis, Rehmannia glutinosa and Plantago asiatica exhibited no significant protection from the T-2 toxin poisoning. A nucleoside, thymidine showed protective activity against T-2 toxin toxicity and it produced a 40% complete survival rate when administered i.p. once 0.5 hr after T-2 toxin treatment. Other natural constituents, aucubin, vitamin C and E, and lipoic acid did not show any significant protective activities.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.2
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• pp.51-64
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• 1986

There has been considerable interest over the last twenty years in the subject of the elastic properties of the cord-rubber laminate. This has been due to the rather intensive study of the composites materials characteristics brought about by the increased use of rigid composites materials characteristics brought about by the increased use of rigid composites in many structural applications. The object of this study is to obtain the natural frequencies and modes of the simply supported cord-rubber laminate plates prior to the study on the analysis of the dynamic properties of the pneumatic tire. To obtain these natural frequencies and modes, the 12 degrees of freedom orthotropic rectangular plate finite elements are developed. By using classical lamination theory, the stress-strain relations are represented. The governing equation for the finite element is derived by energy method. To find the natural frequencies and modes, he eigenvalues and corresponding eigenvectors are computed by the well known Jacobi power method. In order to verify the capability of this present finite element, the results of the specially orthotropic plate and the angle-ply laminate plate are compared with the analytical solution. The analytical and numberical results are in good agreement. The following problems of the simply supported plate are analyzed by the present finite element. a) the natural frequencies and mode shapes of the cord-rubber laminate plate for various aspect ratio. b) The natural frequencies and mode shapes of the orthotropic plate with the rectangular hole in its center.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1092-1099
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• 2009

Landslide researches are divided to a method of interrelationship for various factors, method of predicting landslide possibility, and method of estimating landslide risk which are occurring landslides in the natural slope. Most of landslides occurred in natural slope are caused by a heavy rainfall in summer season. Weathered soil layer located in upper side of rock mass was occurred. As well as, they are announced to have an influence to geometry, geology, soil characteristics, and precipitation in the natural slope. In order to investigate and interpret the variety of landslides from field investigation to risk analysis, landslide analysis process due to geotechnical and geological opinions are systematically demanded. In this research, the study area is located in Macheon area, Gyeongsangnam-do and performed the landslide investigation. From the results of landslide investigation and analysis, optimized standard model based on natural landslide is proposed to high technical method of landslide investigation and interpretation.

• Macromolecular Research
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• v.11 no.4
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• pp.250-255
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• 2003

We prepared the photorefractive sol-gel glass based on organic-inorganic hybrid materials containing a charge transporting molecule, second-order nonlinear optical (NLO) chromophore, photosensitizer, and plasticizer. Carbazole and 2-{ 4-[(2-hydroxy-ethyl)-methyl-amino]-benzylidene}-malononitrile were reacted with isocyanato-triethoxy silane and the functionalized silanes were employed to fabricate the efficient photorefractive media induding 2,4,7-trinitrot1uorenone (TNF) to form a charge transfer complex. The prepared sol-gel glass samples showed a large net gain coefficient and high diffraction efficiency at a certain composition. As the concentration of photosensitizer increased, the photorefractive properties were enhanced due to an increment of charge carrier density. Dynamic behavior of the diffraction efficiency was also investigated with the concentration of the photosensitizer.

• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.319-328
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• 2010

Bonded tendons have been used in reactor buildings at some operating nuclear power plants in Korea. Assessing prestress force on these bonded tendons has become an important pending problem in efforts to assure continued operation beyond their design life. The System Identification (SI) technique was thus developed to improve upon the existing indirect assessment technique for bonded tendons. As a first step, this study analyzed the sensitivity of the key parameters to prestress force, and then determined the optimal parameters for the SI technique. A total of six scaled post-tensioned concrete beams with bonded tendons were manufactured. In order to investigate the correlation of the natural frequency and the displacement to prestress force, an impact test, a Single Input Multiple Output (SIMO) sine sweep test, and a bending test using an optical fiber sensor and compact displacement transducer were carried out. These tests found that both the natural frequency and the displacement show a good correlation with prestress force and that both parameters are available for the SI technique to predict prestress force. However, displacements by the optical fiber sensor and compact displacement transducer were shown to be more sensitive than the natural frequency to prestress force. Such displacements are more useful than the natural frequency as an input parameter for the SI technique.

• The Journal of Korean Academy of Prosthodontics
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• v.19 no.1
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• pp.47-54
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• 1981

Dental porcelains are widely used for restorative material because of its excellent esthetic property. But according to contact with natural teeth or metal in oral cavity, the porcelain may be worn and may effect on masticatory physiology and prosthetic function. The purpose of this experiment was to study on wear of porcelain surface which treated in different method. Using the abrasion device which was designed and constructed by myself, the different porcelain surface were abraded by gold alloy, nickel-chrome alloy and natural teeth in order to compare roughness. Results were as follows. 1. The group of porcelain abraded by gold alloy showed less surface roughness change (t=2.92, p<0.05), and the group of porcelain abraded by natural teeth had high surface roughness. change (t=6.84, p<0.05). 2. According to the method of surface treatment, the surface roughness were very significant (F=9.12, p<0.05). 3. After abrading, the porcelain surface roughness change was very significant (F=54.49, p<0.05). 4. There was no significant between surface treatment method and the kind of abrading materials. (F=1.01, p>0..05). 5. The group of natural glazing had the most smooth surface ($2.1{\pm}1.13{\mu}m$).

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.315-321
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• 1994

In order to prevent the postharvest decay and to promote the freshness retention of fruits and vegetables grapefruit seed extract(GFSE), natural microorganism control agent, was applied to the preservation of fresh fruits and vegetables. Freshfruits and vegetables treated with GFSE and stored in polyethylene film (0.1mm) at 1$0^{\circ}C$-15$^{\circ}C$ of natural low temperature low kept better qualities in color and texture than the GFSE -not- treated control. The treatment using GFSE ina 250ppm to 500ppm concentration seemed to be an effective one for the control of Botrytis cinerea isolated in red wine grapes. After 4 weeks of storage the firmness rate of cucumbers treated with the dilute GFSE was four times higher than that of non-treated ones. GFSE showed effective inhibitory action towards plant pathological bacteria and fungi which were involved in the decay of fruits and vegetables. Minimum inhibitory concentrations of GFSE towards them were in the range of 250ppm to 500ppm .Direct visualization of microbial cells and spores using electron microscopy showed microbial cells and fungal spores the function of which was destroyed by treating with the dilute solutions of GFSE. It was observed that GFSE would reduced disease damages and have bactericide & fungicide properties during the storage of such fruits and vegetables as egg plant, wild edible greens , kumquat, and kiwi fruit.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1241-1245
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• 2005

Solvolyses of trifluoromethanesulfonyl chloride (TFMSC) in water and in aqueous binary mixtures of acetone, ethanol and methanol are investigated at 25, 35 and 45 ${^{\circ}C}$. The Grunwald-Winstein plot of first-order rate constants for the solvolytic reaction of TFMSC with YCl (based on 2-adamantyl chloride) shows marked dispersions into three separate curves for three aqueous mixtures. The extended Grunwald-Winstein plots for the solvolysis of TFMSC show better correlation. The large negative ${\Delta}S^{\neq}$ and relatively small positive ${\Delta}H^{\neq}$ reveals that the solvolytic reaction proceeds via a typical bimolecular reaction mechanism. The l and m values determined in various solvents are consistent with the proposed mechanism of the general base catalysis $S_AN/S_N2$reaction mechanism for TFMSC solvolyses based on mass law and stoichiometric solvation effect studies.