• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.72-79
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• 2008

To meet demand of big capacity and high speed rotation for washing machine, more stress from bending and twisting are complexly loaded onto the shaft supporting the horizontal drum, causing problems in fracture strength and fatigue life. Shafting system is mainly divided into flange and shaft. Shaft and flange connected by inserting shaft serration into flange on the process of die casting. When the system is operating, the gap is formed between serration and flange. But, Serration has various design factors and the optimal values can't be easily determined. Using a design of experiment (DOE) based on the FEM (Finite Element Method), this study was performed investigating the interaction effect between the various design factors as well as the main effect of the each design factor under bending, twist and vibration and proposed optimum design using box-behnken method among response surface derived from regression equation of simulation-based DOE.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.2 no.2
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• pp.131-137
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• 1995

Improving validity and reliability is the important components of clinical laboratory tests. And the quality control of the test should be started with the accurate collection of specimen. Urinalysis is one of the useful and common tests in diseases diagnosis and determining the process of medical treatment. Since urinalysis is requested routinely in hospital setting, the importance of the quality control for urine specimen is often ignored. To improve the validity of urinalysis, a clinical trial was done on the method of collecting urine specimen. The result was as follows : 1. The rate of presumtive UTI(urinary tract infection) was decreased in 21.6% with experiment method for collecting urine specimen. 2. The rate of presumtive UTI in female patients was decreased in 43.2% with the experiment method. 3. The rate of negative urine culture was decreased in 6.6% with the experiment method.

• Environmental Mutagens and Carcinogens
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• v.15 no.2
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• pp.106-114
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• 1995

A method was developed to detect total mutagenicity of fried fish for S. typhimurium TA98, using Ames assay. Method described herein circumvented problems associated with the sample preparation for Ames assay, i.e., a multi-purification step of sample and interference with solvent residuals. Experiment A, the best method developed in the present study, consisted of two important steps: pH adjustment of the aqueous sample solution from fried fish samples to remove impurities, and simultaneous distillation extraction (SDE) for partially purified samples to remove volatile compounds from solvents. The procedure and results were described as below. Fillet of gizzard shad (Konosirus punctatus) fish sample fried for 10 min each side on the temperature-controlled fry-pan (210$\circ$C) was homogenized in an aqueous acidic solution (pH 2) with a homogenizer, followed by filtration through Celite. The tiltrate (pH 2), removed some impurities by extraction with chloroform:methanol (2:1, v/v) mixture, was adjusted pH to 10 and then centrifuged to remove precipitate. The ethylacetate extract from the tiltrate of pH 10 was rotoevaporated and purified by SDE apparatus for 2 hours. Experiment A revealed significantly higher revertants (1928 per 25 g fried sample) than other Experiment (B, C, or D) tested. Experiment A gave good results in the mutagenicity test of fried fish sample with few purification steps using only 25 g fried sample and 650 ml of solvents; and thus this method could be a useful tool for the screening the mutagenicity or antimutagenicity of other foods as well.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.19-25
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• 1998

The bulk curing experiment to the improve the quality of flue-cured leaves were carried out to evaluate relationship between cyclic curing and conventional curing method. We studied the effect of the cyclic change of wet bulb temperature at the yellowing stage of flue curing on chemical properties of cured leaves. The wet bulb temperature was automatically controlled between preset high($38^{\circ}C$) and low point ($35^{\circ}C$) everyone hour cyclically during 12 hours after starting luring. As a result, the acceleration of the increase in the chemical properties of cured leaves were observed. As to the chemical properties, there was decreased in citric acid, increased in malic acid of the nonvolatile organic acids and all higher fatty acids content of leaves cured by this method compared with in that of conventional curing method, while a major chemical compounds in relation to aromatic essence of cigarette smoke in essential oil components of lured leaves was mostly higher in this method than those of conventional ones, and it was evaluated that there was decreased in CO, TPM, Tar, and $CO_2$ content of the cigarette smoke comparing to the conventional luring method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.167-171
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• 2006

In this study, for the establishment of the performance evaluation methods of repair material and method for reinforced concrete structure and the quality control standards of durability recovery method, the quantitative exposure data by exposure experiment under the coastal and normal atmosphere environment is accumulated and analyzed. Investigating and evaluating the result of exposure experiment during 30 months of exposure age under the coastal and normal atmosphere environment, carbonation depth and chlorideion penetration depth very little penetrated than cover depth. It seems reasonable to conclude that main cause of corrosion of reinforcing bar are inner chloride-ion and macro cell from the result of corrosion area and corrosion velocity. Accordingly, it is considered that fundamental data on the performance evaluation and quality control standards of repair material and method could be presented through continuous exposure test in the future.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.175-179
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• 1999

Grape seed oil was extracted using different preparatory treatments as follows: (1) grinding, (2) grinding and roasting, (3) grinding and wet- roasting, (4) grinding, roasting, and wet-roasting, and (5) grinding, wet-roasting, and wet-roasting. The highest antioxidant activity was obtained from the sample with the method (2). Initial states of oxidation were similar except method (1) that showed more oxidized state, being P.O.V.8. Acid values were observed in the range from 1.42 to 1.89. The lowest acid value was found as 1.42 in method (1) and those of others were somewhat higher, indicating that heating process of roasting produced some free fatty acids. From the results of sensory evaluation, the best odor and taste were obtained from the methods (2) and (3). Repetitive procedure of wet-roasting, like method 5, caused some loss of flavor components and decrease in the sensory evaluation score. Addition of grape seed oil (method 2) to soybean and perilla oil at the level of 20% retained considerable antioxidant activities as much as 4.3 and 5 times, respectively, than 100% soybean or perilla oil stored for 12 weeks. When soybean or perilla oil was mixed with 20% grape seed oils, P.O.V. decreased to half of that of unmixed oils.

• Korean Journal of Medicinal Crop Science
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• v.17 no.6
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• pp.427-433
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• 2009

Volatile flavor compounds from the shoot and root of Angelica gigas Nakai were extracted by HE (Hydrodistillation extraction), SDE (Simultaneous steam distillation & extraction), and SFE (Supercritical fluid extraction system), and analyzed by GC-MS. The amount and the number of chemical components in essential oils from shoot and root by SFE was the higher than those by other extraction methods. Respectively, thirty one constituents were identified from the essential oil of the shoot and root by HE, twenty seven and twenty three constituents were identified from the essential oil of shoot and root by SDE, thirty one and forty five constituents were identified from the essential oil of shoot and root by SFE. The result showed large differences in extraction methods and in plant parts of Angelica gigas Nakai. Also, the bioactive compounds in root part was identified as nodakenin and decursinol (11.95% and 8.42%, respectively) by SFE. These results suggested that SFE was the best extraction method for the increasing of extraction yield, the determination of volatile components and the increasing of bioactive compounds in the shoot and root of Angelica gigas Nakai.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.655-658
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• 1999

In this paper, Parallel operation of two DC-DC converters which we have ever done before need two CTs to do load current sharing. However, we have proposed a new method called ZCT method that can share load current with only a CT as doing parallel operation two converters with same converter capacity. To confirm parallel performance by a proposed DC-DC converter parallel operation method, we have done computer simulation and experiment. It is certain that we have showed to achieve two converters current sharing performance efficiently through simulation and experiment at result.

• Communications of Mathematical Education
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• v.20 no.4 s.28
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• pp.575-586
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• 2006

Both theory and experiment are very important parts in sciences. Especially in mathematics, theory seems to be very important, but experiment or practice doesn't. Numerical analysis of many parts in mathematics needs practice in computer. In this paper, I suggest that computer-practicing in teaching power method, inverse power method and deflation to calculate eigenvalues and eigenvectors is good in understanding the theory. It also makes students sure that mathematics is helpful.

• Journal of the Korean Society for Nondestructive Testing
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• v.10 no.1
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• pp.91-95
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• 1990

Welding residual stress was measured by Barkhausen noise method. The calibration experiment was done for the quantitative analysis. The specimen for the calibration experiment must has the same thermo-mechanical history as the actual material to be tested. The Barkhausen noise were analysed by the pulse-height distribution. The results show that the distribution and magnitude of welding residual stress from Barkhausen noise method are in good agreement with those from blind hole method.