• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.710-713
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• 2003

The wall charge is major factor to determine the discharge characteristics. The minimum sustain voltage related to the wall charge decay were investigated as a function of aging time in AC plasma display panel. For the long time scale, the wall charge decay time is dependent on the aging time. The inverse time scale of the wall charge decay has the maximum value at around 3 hours aging time and then fell down.

• Phonetics and Speech Sciences
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• v.4 no.2
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• pp.135-143
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• 2012

Discourse is regarded as an important component of communication assessment, but studies about the discourse characteristics of the elderly are scant. The purpose of this study was to confirm the effects of aging, gender, and educational level on discourse in elderly people with normal cognitive function. Forty normal elderly and forty young people participated in this study. A picture description task (Boston Cookie-Theft picture) was used to examine discourse function. The description task was analyzed for both productivity (total number of sentences, total number of syllables, and syllables per sentence) and semantics (CIU ratio). The results were as follows: 1) Only CIU ratio differed significantly according to age. 2) In the total number of syllables and syllables per sentence, females demonstrate a higher number than males. 3) The CIU ratio differed significantly according to educational level. These results suggest that impairment of communicative function is an aspect of cognitive impairment that can be related to aging. Also, discourse performance in the elderly is associated with their gender and educational level.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1615-1618
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• 1994

This paper studied the streaming electrification of the U.H.V. transformer with the spinning cylinder system, and compared and analyzed it with the conventional forced flowing system which uses a pump or gas for oil flowing. Also, accumulated surface voltage in its electrified material was measured with the electrostatic voltmeter, and the effect of insulation oil aging was measured. As results, in spinning cylinder system, characteristics of the streaming electrification to its rotational speed and oil temperature are same tendency as those of tile forced flowing system and it showed the spinning cylinder system is useful to study the streaming electrification. And, aging of insulation oil increases the electricity of streaming electrification at initial stage of aging.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.492-497
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• 2017

In this study, we investigated the effect of thermal aging on mechanical characteristics of Inconel 600 nickel-based alloy. The thermal aging was conducted up to 1000 hours at an atmosphere of $650^{\circ}C$. The microstructure of thermally aged specimens was investigated by an optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). In addition, tensile test (strain rate: 2 mm/min) and micro Vickers hardness test were conducted to evaluate mechanical properties with time. As a result of the experiment, Cr-rich carbide continuously precipitated during thermal aging, leading to the change of the mechanical characteristics and fracture mode. With the increase of aging time, tensile strength, yield strength, and hardness gradually decreased. The fracture mode changed from ductile to brittle with the increase of grain boundary carbide.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.49-53
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• 2006

In this paper the thermal aging characteristics of transformer fluid were considered. First, the temperature rise characteristic in transformer winding was discussed. The temperatures were rapidly increased immediately with applying load and then the temperature was followed the exponential temperature rise model. Next, Capacitance and leakage current characteristics of the transformer fluid were measured during the over-loading operation. The capacitance of vegetable fluid and leakage current were evidently increased wit aging time. So the simple methods could be applied to diagnosis of the transformer aging

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.449-452
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• 2004

The life of power transformer is basically dependent on the aging deterioration of insulating paper. Analysis of insulating paper for its DP value or tensile strength requires removal of a few strips of paper but direct measurement of this properties is not practical for in-service transformers. For this reason furfural analysis by HPLC has gained increasing favor as a means of estimating degradation of insulating papers in power transformers and this paper reports on the analysis of data on the concentration of furfural in oil samples from about 50 power transformers and the case study. The data showed that furfural content can estimate more accurately aging characteristics compared to concentration of CO, $CO_2$. We expect that these results can be useful to predict the aging characteristics and life diagnosis of power transformers and further the study must be continued.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1175-1179
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• 2009

We analyze voltage characteristics of charged particle type display according to particle layers and cell gap between two electrodes and ascertain the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of charged particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for charged particle type display.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1169-1181
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• 2021

We investigated the comparative physicochemical attributes, oxidative stability, and microbial characteristics of 28 days dry-aged meat in between boneless sirloin (gluteus medius) and bone-in T-bone steaks (infraspinatus) muscles from Korean Native Hanwoo Steer (KNHS). Results reveal that regardless of the muscles, dry-aging increased protein content and water-holding capacity (WHC) (p < 0.05). Meat from infraspinatus-aged muscle led to darker meat with higher pH values than un-aged meat (p < 0.05). However, fat content, CIE a^*, and CIE b^* remained unchanged in both muscles at aging. At aged meat, thiobarbituric acid reactive substances (TBARS) values from bone-in infraspinatus muscle was 2.5-fold higher than boneless gluteus medius muscle (p < 0.05). Dry-aging led to an increase in the contents of total unsaturated fatty acids (UFAs), monounsaturated fatty acids (MUFAs), and UFA/saturated fatty acids (SFA) in both muscles (p < 0.05). Furthermore, gluteus medius aged muscle concentrated with olic acid (C18:1) compared to infraspinatus aged muscle. Irrespective of the muscles, dry-aging enhanced the total free amino acids (FAAs) as well as tasty, and bitter amino acid contents whereas decreased the tasty/bitter amino acids (p < 0.05). Aromatic amino acid, tryptophan that converted to serotonin was 2-fold higher in boneless gluteus medius muscle than bone-in infraspinatus muscle at pre and post aging processes (p < 0.05). Aged Infraspinatus muscle increased total bacteria (p < 0.05) while no salmonella spp. was detected in both muscles. Taken together, our study confirms that 28 days dry-aging profiling the quality characteristics of boneless sirloin (gluteus medius) and bone-in T-bone steaks (infraspinatus) distinctly while gluteus medius aged steak performs better owing to oxidative stability and functional compounds than infraspinatus aged steak.

• The Korean Journal of Food And Nutrition
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• v.34 no.1
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• pp.58-68
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• 2021

This study investigated the microbial community and quality characteristics of traditional soybean pastes (doenjang) based on the aging period in Gyeongnam province. The samples were collected from seven regions in Gyeongnam Province (Goseong, Hadong, Haman, Hamyang, Sacheon, Sancheong and Uiryeong). Contents of moisture, salinity, pH, and acidity of doenjang after 210 days aging were 56.40~65.21%, 9.05~16.08%, 4.88~6.86 and 0.64~2.14%, respectively. Lightness significantly decreased over the aging period, while the redness tended to increase over the aging period. Yellowness was from 21.39~26.81 to 21.10~28.36. Reducing sugar content was from 0.31~1.45% to 0.11~3.13%. The amino-type content increased from 141.87~495.13 mg/100 g to 328.53~823.67 mg/100 g. In contrast, the ammonia-type content declined from 136.74~364.70 mg/ 100 g to 128.62~331.00 mg/100 g. The overall total microbial count did not significantly differ, but it tended to decrease in sample GD4. Fungus declined overall or was not detected. Coliform groups were not detected in all samples. Lactobacillus and Bacillus cereus tended to decrease over the aging period. The common fungus and bacterium were Aspergillus oryzae and Tetragenococcus halophilus, respectively. After the aging period, the predominant fungi were Candida versatilis, Candida apicola, and Debaryomyces hansenii. The predominant bacteria were Tetragenococcus halophilus and Cronobacter sakazakii.

• Composites Research
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• v.22 no.6
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• pp.39-44
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• 2009

The effect of exposure times on the aging characteristics of carbon fiber/epoxy composite ring specimen was evaluated using an accelerating aging tester. Combined exposure conditions, such as temperature, moisture, and ultraviolet, were applied up to 3000 hours. Tensile properties and flexural properties including the effect of curvature were evaluated on the specimens subject to various exposure times through a material testing system. Their aging surfaces were observed through a scanning electron microscope. According to the results, tensile modulus was little affected by the exposure times. However, tensile strength, at the early stage of the exposure times, increased due to physical aging and curing reaction, but tensile strength slightly decreased due to degradation as the exposure times increased. The flexural modulus and flexural strength increased at the early stage of the exposure times, but slightly decreased as the exposure times increased. Aging surfaces of the specimens examined using the scanning electron microscope revealed a different morphology in various exposure times and provided useful information for identifying the degradation in mechanical properties of the composite subject to various exposure times.