• 대한가정학회지
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• 제29권4호
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• pp.37-43
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• 1991

Oxidative stability of crude wheat germ oil (WGO) was determined by the active oxygen method(Rancimat, hrs at 98$^{\circ}C$). The induction time of crude WGO was 7.6hrs as compared to 23.7hrs of crude soybean oil. However, the induction time of WGO could be extended by 2-3 times with 300ppm of mixed tocopherols and 200ppm of organic acids. The antioxidant effect of organic acids increased in the order of L-ascorbic acid > tartaric acid > citric acid > malic acid. Especially, the induction time of WGO could be extended by ca. 38hrs with 500ppm of L-ascorbic acid. This antioxiative effect of 500ppm L-ascorbic acid with mixed tocopherol(100, 200, 300 or 500ppm). It seems that the synergistic effect of L-ascorbic acid was due to the high content of tocopherols(0.4%) in WGO.

• 한국염색가공학회지
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• 제6권1호
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• pp.19-27
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• 1994

Mimosa and Quebracho are, in general, tanned with leather skin, finished silk fabrics according to temperature, treatment time, tannin concetration, pH, and studies that relation between tannin weighting and various factors. This makes fundamental study on characteristic of tannin treated fabrics. and the results are as fallows : 1. λ$_{max}$ was found at 278.5nm for Mimosa. 279.5nm for Quebracho. Also a stability was good in standing time and heating. 2. The higher tannin treatment temprature was, the better tannin weighting effect was. But they were slightly decreased at over 8$0^{\circ}C$, and K/S was slowly increased. 3. As tannin treatment time increased, tannin weighting effect increased but they were decreased at over 8$0^{\circ}C$, 90min. 4. As tannin concentration increased, tannin weighting was increased. 5. In tannin weighting effect according to various pH conditions, the it's best range of pH were 3.5~5.5 of Mimosa, 2.5~3.5 of Quebracho.o.

• International Journal of Contents
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• 제16권1호
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• pp.44-56
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• 2020

The purpose of this study was to examine how the presentation mode (sequential- vs. simultaneous-mode) of information influences its evaluation. Three experiments revealed the interaction effect between the presentation mode and the valence of the product information. When respondents read about the positive aspects of the product, the evaluation was higher in the simultaneous presentation mode than in the sequential presentation mode. For negative product information, respondents' evaluation was higher in the sequential presentation mode than in the simultaneous presentation mode. The simultaneous presentation mode intensified the impact of the information valence on evaluation. This study proposed that the sequential and the simultaneous presentation modes prime high and low construal levels, respectively. The mediation analysis provides support for such a prediction. Finally, the mediating effect of construal levels in evaluation was shown to disappear when respondents focused on the product information for a longer duration, while the mediation effect remained when the response time was short.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.16-24
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• 2007

The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.775-784
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• 2010

In this paper we propose a design method of X band frequency hopping synthesizer in terms of phase noise and settling time with DDS driven PLL architecture, which has the advantages of high frequency resolution, fast settling time and small size. In addition, a noble method is proposed to remove the synthesizer output spurious signals due to superposition effect of DDS. The spurious signal which depend on its normalized frequency of DDS, can be dominant if they occur within the PLL loop bandwidth. We verify that the sources of that spurious signals are quasi-amplitude modulation and superposition effect, and suggest that such signals can be eliminated by intentionally creating frequency errors in the developed synthesizer.

• Geomechanics and Engineering
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• 제32권5호
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• pp.475-482
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• 2023

This paper studies the effect of the relaxation time on a two-dimensional thermoelastic medium which has a doubly porous structure in the presence of diffusion and gravity. The normal mode analysis is used to obtain the analytic expressions of the physical quantities, which we take the solution form in the exponential image. We have discussed a homogeneous thermoelastic half-space with double porosity with the effect of diffusion and gravity. The equations of generalized thermoelastic material with double porosity structure with one relaxation time have been developed. Moreover, the expressions of many physical quantities are explained. The general solutions, under specific boundary conditions of the problem, were found in some detail. In addition, numerical results are computed.

• 한국정밀공학회지
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• 제11권6호
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• pp.5-11
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• 1994

We have investigated the variation of dwell and warm-up time for effects of positioning accuracy of the CNC machine tools with an laser measuring system. Also, we strdied the effect of improvement of the positioning accuracy by variation of the temperature for hollow ball screw, which mostly used as drive mechanism of CNC machine tools. We dbtained the effectiveness of cooling effect of the new cooling system, compared with the conventional cooling system.

• Advances in materials Research
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• 제2권1호
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• pp.51-64
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• 2013

Enantioselective macromer of trimesic acid was prepared using S(-) menthol with trimesoyl chloride on polyimide (PI) ultrafiltration membrane. The chemical composition of macromer as well as polyimide ultrafiltration membrane was determined by ATR-FTIR Spectroscopy. The optical resolution of chiral alcohols was performed in pressure driven process. The effect of monomer solutions concentration, effect of air-drying time of S(-) menthol solution, effect of reaction time, effect of operating pressure, effect of feed concentration of racemate on the performance of macromer was studied. The synthesised material exhibits separation of chiral alcohols (menthol ~23% and sobrelol ~21%).

• 말소리와 음성과학
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• 제1권4호
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• pp.105-109
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• 2009

This thesis describes the method for well voice announcement using the TTS(Text-To-Speech) technology in the shop music broadcasting service. Offering a high quality TTS sound service for each shop requires a great expense. According to a report on the architectural acoustics the room acoustic indexes such as reverberation time and early decay time are closely connected with a subjective awareness about acoustics. By using the result the customers will be able to recognize better the voice announcement by applying sound effect to speech files made by TTS. The result of an aural comprehension examination has shown better about almost all of the parameters by applying reverb effect to TTS sound.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.924-927
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• 2007

In this study, adaptation of two-way shape memory effect of SMA wire to the actuator is examined. Therefore the SMA characteristics which are training, material properties, response time at different thermal cycling rates are tested. During training, permanent deformation is accumulated till a certain number of cycle and then saturated. The amount of two-way strain is unchangeable over all cycle and the slope of strain(or stress)-temperature curve is slower as the increase of applied stress. The rate effect is observed resulted from the thermal distribution which heating profile differs from cooling as thermal cycling time. Using the estimated SMA properties, an experimental test for the simple smart wing is performed.