• Applied Chemistry for Engineering
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• 제31권4호
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• pp.347-351
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• 2020

A material changes its physical and chemical properties through the interaction with radiation and also the neutrons, which is electronically neutral so that the penetration depth is relatively deeper than that of other radioactive way including alpha or beta ray. Therefore, the radiation damage by neutron irradiation has been intensively investigated for a long time with respect to the safety of nuclear power plants. The damage induced by neutron irradiation begins with the creation of point defects in atomic scale in the unit of picoseconds, and their progress pattern can be characterized by microstructural defects, such as dislocation loops and voids. Their morphological characteristics affect the properties of neutron-irradiated materials, therefore, it is very important to predict the microstructure at a given neutron irradiation condition. This paper briefly reviews the evolution of radiation damage induced by neutron irradiation and introduces a phase-field model that can be widely used in predicting the microstructure evolution of irradiated materials.

• Journal of the Korean Ceramic Society
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• 제51권3호
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• pp.170-176
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• 2014

Effective glass frit compositions enabled to absorb laser energy, and to seal a commercial dye-sensitized solar-cell-panel substrate were developed by using $V_2O_5$-based glasses with various amounts of $TeO_2$ substitution. The latter was intended to increase the lifetime of the solar cells. Substitution of $V_2O_5$ by $TeO_2$ provided a strong network structure for the glasses via the formation of tetrahedral pyramids in the glass, and changed the various glass properties, such as glass transition temperature ($T_g$), dilatometric softening point ($T_d$), crystallization temperature, coefficient of thermal expansion (CTE), and glass flowage without any detrimental effect on the laser absorption property of the glasses. The thermal expansion mismatch (${\Delta}{\alpha}$) between the glass frit and the substrate could be controlled within less than ${\pm}5%$ by addition of 10 wt% of ${\beta}$-eucryptite. An 810 nm diode laser was used for the sealing test. The laser sealing test revealed that the VZBT20 glass frit with 10 wt% ${\beta}$-eucryptite was successfully sealed the substrates without interfacial cracks and pores. The optimum sealing conditions were provided by a beam size of 3 mm, laser power of 40 watt, scan speed of 300 mm/s, and 200 irradiation cycles.

• Journal of Radiation Protection and Research
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• 제24권1호
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• pp.1-7
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• 1999

Using the TBP slovent extraction method, a simple and precise method for determining uranium isotopes in the environment samples was developed. The soil sample was decomposed with $HNO_3$ and HF. Uranium isotopes were extracted with 15% TBP in $CCl_4$ from aqueous phase to organic phase, and Th fraction was removed with 8M HCl. Uranium fraction was purified in back extraction step with 1M HCl. Optimized electrode position conditions of uranium Isotopes were set using a new electrode position solution including a DTPA chelating agent. The new method of uranium isotopes determination was validated with a result of application to IAEA Reference Soils.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제44권3호
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• pp.183-190
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• 2011

This study was performed to assess the antioxidative properties of lipid from aquacultured mackerel Scomber japonicus fed with a diet fortified with conjugated linoleic acid (CLA) and ascidian Halocynthia roretzi tunic extracts by radical scavenging assay. The fish were separated into squid oil (Control) and 2.5% CLA (CA25) groups during the 8-week feeding period. The reducing power of each sample showed high levels of activity compared with ${\alpha}$-tocopherol and butylated-hydroxyanisol (BHA) at 0.2-1.0 mg/mL of lipid. Inhibition of linoleic acid oxidation in samples from Control and CA25 groups showed similar activity after 2 days of incubation at $40^{\circ}C$. The 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide, and hydroxyl radical scavenging activities of CLA and carotenoid-deposited sample (CA25) were higher than those of the Control group. The results indicated that the lipid extracted from the viscera of mackerel showed slightly higher antioxidant activities than that from the muscle.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.259.1-259.1
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• 2014

Recently non-thermal plasma has been frequently applied to various research fields. The liquid plasma have received much attention lately because of interests in surgical and nanomaterial synthesis applications. Especially, intensive researches have been carried out for non-thermal plasma in liquid by using various electrode configurations and power supplies. We have developed a bioplasma source which could be used in a liquid, in which outer insulator has been covered onto the outer electrode. Also we have also put an insulator between the inner and outer electrode. Based on the surface discharge mode, the nonthermal bioplasma has been generated inside a liquid by using an alternating current voltage generator with peak voltage of 12 kV under driving frequency of 22 KHz. Here the discharge voltage and current have been measured for electrical characteristics. Especially, We have measured discharge and optical characteristics under various liquids of deionized (DI) water, tap water, and saline by using monochromator. We have also observed nitric oxide (NO), hydrogen peroxide (H2O2), and hydroxyl (OH) radical species by optical emission spectroscopy during the operation of bioplasma discharge inside various kinds of DI water, tap water, and saline. Here the temperature has been kept to be $40^{\circ}C$ or less when discharge in liquid has been operated in this experiment. Also we have measured plasma temperature by high speed camera image and density by using either H-alpha or H-beta Stark broadening method.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.328-329
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• 2012

$SF_6$ gas는 반도체 및 디스플레이 제조공정 중 Dry etch과정에서 널리 사용되는 gas로 자연적으로 존재하는 것이 아닌 사용 목적에 맞춰 인위적으로 제조된 gas이다. 디스플레이 산업에서 $SF_6$ gas가 사용되는 Dry etch 공정은 주로 ${\alpha}$-Si, $Si_3N_4$ 등 Si계열의 박막을 etch하는데 사용된다. 이러한 Si 계열의 박막을 식각하기 위해서는 fluorine, Chlorine 등이 사용된다. fluorine계열의 gas로는 $SF_6$ gas가 대표적이다. 하지만 $SF_6$ gas는 대표적인 온실가스로 지구 온난화의 주범으로 주목받고 있다. 세계적으로 온실가스의 규제에 대한 움직임이 활발하고, 대한민국은 2020년까지 온실가스 감축목표를 '배출전망치(BAU)대비 30% 감축으로' 발표하였다. 따라서 디스플레이 및 반도체 공정에는 GWP (Global warming Potential)에 적용 가능한 대체 가스의 연구가 필요한 상황이다. 온실가스인 $SF_6$를 대체하기 위한 방법으로 GWP가 낮은 $C_3F_6$가스를 이용하여 $Si_3N_4$를 Dry etching 방법인 RIE (Reactive Ion Etching)공정을 한 후 배출되는 가스를 측정하였다. 4인치 P-type 웨이퍼 위에 PECVD (Plasma Enhanced Chemical Vapor Deposition)장비를 이용하여 $Si_3N_4$를 200 nm 증착하였고, Photolithography공정을 통해 Patterning을 한 후 RIE공정을 수행하였다. RIE는 Power : 300 W, Flow rate : 30 sccm, Time : 15 min, Temperature : $15^{\circ}C$, Pressure : Open과 같은 조건으로 공정을 수행하였다. 그리고 SEM (Scanning Electron Microscope)장비를 이용하여 Etching된 단면을 관찰하여 단차를 확인하였다. 또한 Etching 전후 배출가스를 포집하여 GC-MS (Gas Chromatograph-Mass Spectrophotometry)를 측정 및 비교하였다. Etching 전의 경우에는 $N_2$, $O_2$ 등의 가스가 검출되었고, $C_3F_6$ 가스를 이용해 etching 한 후의 경우에는 $C_3F_6$ 계열의 가스가 검출되었다.

• Science of Emotion and Sensibility
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• 제3권2호
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• pp.17-28
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• 2000

Psychoacoustic characteristics of automobile horns play significant role in resulting subjective evaluation and psychphysiological reactions. However, comparison and differentiation of physiological responses to commercially available horns is a complicated task due to the small contrast in technical features of horns and the influence of such processes as habituation on physiological outcome with the increased number of auditory stimulation trials. In a study on 10 college students, there was performed comparative analysis of reactivity of physiological responses mediated by central and autonomic nervous systems in order to identify the role of habituation on decrement of psychophysiological responsivity and assess the ability to differentiate subjectively most and least preferred, as well as most and least appropriate horns according to physiological manifestations. The EEG and autonomic responses to 7 automobile horns were analyzed during 3 blocks of trials, with varying order of stimuli and changed acoustic parameters of horns in each block. Thus, responses were analyzed for totally 21 trials of auditory stimulation. It was shown that electrodermal and cardiovascular responses have different reactivity patterns to repeated stimulation: skin conductance measures habituated, cardiac reactivity showed no signs of habituation, and the vascular response demonstrated sensitization. The temporal EEG exhibited marked habituation of fast beta band power, while alpha-blocking effect did not habituate during the course of experiment. Differentiation of physiological responses of most and least preferred and appropriate horns was possible in our study, however, some cardiovascular reactivity measures differentiated during the entire course of the experiment, while EEG and electrodermal parameters showed significant differences only during first block of trials, and were later affected by the habituation.

• Korean Journal of Food Science and Technology
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• 제35권1호
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• pp.44-51
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• 2003

찹쌀가루와 메주가루의 배합비율(무게비)을 달리한 고추장(찹쌀가루 : 메주가루 = 1:1, 1:2, 1:3, 2:1, 3:1)의 숙성 중 품질 변화를 평가하기 위해 12주 동안 숙성시키면서 고추장의 이화학적 특성, 효소 활성 및 레올로지 특성을 연구하였다. 숙성 중 고추장의 수분함량은 $47.4{\sim}47.9%$에서 점차 증가하여 8주에는 최대 수분함량을 보였다. 환원당 함량은 $2{\sim}4$주에 가장 높았으며 이후에서는 점차 감소하는 경향을 보였다. 아미노태 질소 함량은 지속적으로 증가하였다. ${\alpha}-amylase$와 ${\beta}-amylase$ 활성은 숙성 $2{\sim}4$주에 최대 역가를 나타냈다. Acidic protease와 neutral protease는 각각 숙성 2주와 4주에 가장 높은 활성을 보였다. Power law 모델에 의한 유동성 측정에서 고추장은 낮은 유동성지수(flow behavior index, $n=0.21{\sim}0.36$)를 가진 전단담화(shearing-thinning)거동을 보여주었으며, 점조도 지수(consistency index, K)와 겉보기점도 $({\eta}_{a,10})$는 숙성 2주에 급격히 증가하고 이후에는 감소하였다. Casson 모델식에 의한 항복응력$({\sigma}_{oc})$은 숙성 2주에 급격히 증가하고 이후에는 감소하였다. 동적 점탄성 측정에서는 저장 탄성률 (G#)이 손실탄성률 (G') 보다 높은 수치를 나타내었고 주파수(frequency, ${\omega}$)가 증가함에 따라 증가하는 경향을 보여주었다. 또한 숙성기간이 경과함에 따라 (G#)과 (G@)이 증가하는 경향을 나타냈다.

• Journal of the Korean Home Economics Association
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• 제30권3호
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• pp.33-43
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• 1992

The objective of this study were to (1) investigate the relationship between evaluations of apparel advertising, fashion involvement, and social attitudes, (2) examine how evaluation of apparel advertising, fashion involvement, and social attitudes vary according to gender, and (3) investigate the possible differences in purchase attitudes toward the advertised apparels according to gender and advertisement slogan. Questionnaire for evaluations of apparel advertising was comprised of four sections; apparel advertising acceptance, evaluation of advertisement slogan, purchase attitude toward the advertised apparels, and perception of effective media for apparel advertising. For evaluation of advertisement slogan, 5 sets of apparel advertisements were selected. Each set had two advertisements; one advertisement contained an image-oriented slogan, while the other had a quality-oriented slogan. "The Social Attitude Scale' by Kerlinger and 'Fashion Involvement Index' by Tigert, Ring & King were used. All the items were selected on the Cronbach's alpha reliability. The subjects were 217 college male and famale students in Seoul; 60 were asked about purchase attitude toward the image-oriented slogan, 60 purchase attitude toward the quality-oriented slogan, and 97 all the items included in evaluation of the two slogans. The data were analyzed using Pearson's correlation coefficient, X2-test, t-test, two-way ANOVA, and multiple regression analysis. The results of the study were the followings. 1. Fashion involvement had positive relationship with apparel advertising acceptance. The higher the level of conservative attitude males had, the more positive attitude they had in fashion involvement and apparel advertising acceptance. Subjects high in conservative attitude, fashion involvement, and apparel advertising acceptance. Subjects high in conservative attitude, fashion involvement, and apparel advertising acceptance had more positive in purchase of the advertised apparels. 2. Females high in apparel advertising acceptance were more favorable toward image-oriented advertisements. 3. Fashion involvement and apparel advertising acceptance were significantly higher in females than in males. Liberal attitude was significantly higher in males than in females. Evaluation of advertisement slogan did not differ according to gender. 4. Males perceived 'TV' was the most effective media for apparel advertising while females perceived 'display' was the most effective. 5. No significant interactions between advertisement slogan and gender were found in purchase attitude of the advertising apparels. 6. Apparel advertising acceptance was influenced by fashion involvement, social attitude, and sex. The explanatory power of the three variables was 17%.

• Journal of the Korean Dietetic Association
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• 제10권4호
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• pp.428-441
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• 2004

This study focused on developing and assessing the effectiveness of maternal and child nutrition education materials that can be used conveniently at health centers. Focus group interviews with pregnant women, research of websites for pregnant women, and questionnaire-based surveys on community residents' needs for maternal and child nutrition services were conducted as preliminary study. The focus group interviews were conducted ten times, with five or six women, and the needs assessment was carried out on 884 pregnant or lactating women. The contents of the education materials developed based on the preliminary study were made up of the pregnant women section and the lactating women section. The entire material was composed of lecture materials, guidelines for educators, and handout materials for mothers, in the form of CD and booklets. The lecture materials were made using MS Power Point and the guidelines were wrote specifically, including basic information, main points to the lectures, and lesson plans, so that even non-professionals can easily use them. The effectiveness of the education materials was assessed based on a pretest and posttest method. The reliability of the test instrument was measured by Cronbach alpha, which was 0.75. The results were that the participants' nutrition knowledge scores showed a significant increase(p<0.05) from 3.79$\pm$0.33 to 3.96$\pm$0.34, and their attitudes changed positively after the education (p<0.05).