• KSBB Journal
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• v.15 no.3
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• pp.299-306
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• 2000

Concern for the effects of toxic chemicals on the environment leads the search for better bioassay test organisms and test procedures. Photobacterium phosphoreum was used successfully as a test organism and the luminometer detection technique was an effective and simple method for determining the concentration of toxic chemicals. With EC50 a total of 14 chlorine substituted phenols benzenes and ethanes were used for the experiments. The test results showed that the toxicity to P. phosphoreum increased in the order of phenol > benzene > ethane and the toxicity also increased with the number of chlorine substitution. Quantitative structure activity relationship (QSARO) model can be used to predict EC50 to save time and endeavor. Correlation was well established with the QSAR parameters such as log P, log S and solvatochromic parameter(Vi/100 $\pi$, ${\beta}$m and am). The QSAR modeling was used with multi-regression analysis and mono-regression analysis. These analyses resulted in the following QSAR : $log EC_{50} =2.48 + 0.914 log S(n=9 R2=85.5% RE=0.378) log EC_{50}=0.35 - 4.48 Vi/100 + 2.84 \pi^* +9.46{\beta}m-4.48am (n =14 R2=98.2% RE=0.012) log EC_{50} =2.64 -1.66 log P(n=5, R2=98.8% RE=0.16) log EC_{50}=3.44 -1.09 log P(n=9 R2= 80.8% Re=0.207)$

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.37-38
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• 2007

This paper reports the characteristics of piezoelectric microspeakers that are audible in open air with high quality piezoelectric AlN thin film according to the materials properties. When we use a tensile-stressed silicon nitride diaphragm as a supporting layer, the Sound Pressure Level (SPL) is relatively small. However, the SPL of the fabricated microspeakers that have compressive-stressed composite diaphragm show higher output pressure than those of tensile-stressed diaphragm. It produces more than 60dB from 100Hz to 15kHz and the highest SPL is about 100dB at 9.3kHz with 20 Vpeak-to-peak sinusoidal input biases and at 10 mm distances from the fabricated microspeakers to the reference microphone.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.485-498
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• 2008

This study was conducted to evaluate effects of dietary rare earth on growth performance, blood immune- related cell population, meat quality and fecal odor emitting gases in finishing pigs. The total of sixty four (Landrace×Yorkshire×Duroc) pigs(65.42±1.16kg in average initial body weight) were used for feeding trial during 10 weeks of experimental period. Dietary treatments included 1) NC(antibiotic free diet), 2) PC (NC diet+6 weeks 44ppm of tylosin/ 4 weeks 22ppm of tylosin) 3) RE1 (NC diet + 100ppm of RE), 4) RE2 (NC diet+200ppm of RE). There were four dietary treatments with four replicate pens per treatment and four pigs per pen. During the overall periods, there were no significant differences in ADG(Average daily gain), ADFI (Average daily feed intake) and gain/feed ratio among treatments(P>0.05). Dry matter and nitrogen digestibility were higher in RE2 treatment group than other groups(P<0.05). Also, energy digestibility was higher in RE2 treatment group than PC and RE1 treatment groups(P<0.05). At the 6th week WBC(white blood cell) was significantly increased(P<0.05) in RE1 treatment group than NC and RE2 treatment groups. L* value of M. logissimus dorsi muscle color was significantly increased(P<0.05) in rare earth supplemented groups compared to NC treatment group(P<0.05). However, a* value was lower in RE1 treatment group than PC treatment group (P<0.05). In fatty acid composition of Intramuscular fat, total MUFA was significantly higher in RE2 treatment group than other groups(P<0.05). Also, total UFA was significantly increased in RE2 treatment group compared with NC and PC treatment groups(P<0.05). In fatty acid composition of back fats, total SFA of rare earth supplemented groups were lower than in PC treatment group(P<0.05). UFA:SFA ratio was significantly higher in rare earth supplemented groups than PC treatment group(P<0.05). In fecal odor emission, NH3 was significantly decreased(P<0.05) in rare earth supplemented groups compared to NC and PC treatment groups. In conclusion, the results of the experiment was affected by rare earth supplementation on digestibilities, meat quality, fatty acid and fecal odor emission gases in finishing pigs.

• Journal of Korean Society of Forest Science
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• v.97 no.5
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• pp.547-551
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• 2008

The study aimed to develop a cryopreservation method for long-term storage using mature somatic embryo of Japanese larch. In this study, desiccation treatments significantly affected re-induction rates of embryogenic tissue (ET) from dried somatic embryos. In the effect of different dehydration temperature and duration on the re-initiation ET. the highest frequency was shown when somatic embryos were dehydrated at $25^{\circ}C$ for 2 (45.5%) or 1 day (43.3%), respectively. In addition, low temperatures [$4^{\circ}C$, 2 days (44.2%) or 3 days (43.5%)] were marked higher ET initiation. After that, the initiation value was declined with dehydration duration. For comparison of different relative humidity on re-induction frequency of ET, the best re-induction (43.5%) was obtained from somatic embryos pre-dried at $(NH_4)_2SO_4$ (RH 79%). Both $Na_2HPO_4$ (RH 97%) and $Na_2CO_3$ (RH 88%) treatments were showed the similar rate, 34.6, 34.2%, respectively. However the lowest rate (19.6%) was observed in distilled water (RH 100%). In comparison of the various storage temperatures and duration of the dried somatic embryos, the highest frequency (66.9%) of re-initiation was obtained when somatic embryos were cryopreserved for one day. However, the frequency was gradually decreased as the time length of storage increased regardless of types of storage. None of ET re-initiated when stored at $4^{\circ}C$ for 1, 2 and 84 days.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.3
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• pp.566-573
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• 2016

Sustainability in fashion cannot ignore fashion attributes required for the design of rapidly changing and innovative products. This study examines "Re-Birth Design" development and provides a means to apply academic and industry perspectives to the investigation of Re-Birth fashion product development. This study defines "Re-Birth Design" as stock that has been designed and launched through distribution channels, subsequently returned unused, then improved and reborn into a new product for redistribution. This study analyzed specific cases. We selected 100 designs for Re-Birth from 11 brands of "K" fashion company in Korea, to be successfully sold in 2014. These cases are used in the analysis and are categorized into design types. As a result of the analysis, "Re-Birth Design" had five levels: Level 1. Changes in supplementary materials such as adding or removing decoration, Level 2. Changes in patterns or materials (changes within the product), Level 3. Partial changes in design (leading to a new design), Level 4. Complete deconstruction and rebirth of the design, and Level 5. Complete deconstruction followed by the use of the design source for a new product that is not a garment. This study analyzed products owned by brands, as well as successful cases of Re-Birth designs that reused existing resources, reduced energy consumption, and increased environmental and economic efficiency by recreating new products that could be resold.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1013-1021
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• 2024

A series of experiments were performed to produce a fuel source for a molten salt reactor (MSR) through pyroprocessing technology. A simulated LiCl-KCl-UCl₃-NdCl₃ salt system was prepared, and the U element was fully recovered using a liquid cadmium cathode (LCC) by applying a constant current. As a result, the salt was purified with an UCl₃ concentration lower than 100 ppm. Subsequently, the U/RE ingot was prepared by melting U and RE metals in Y₂O₃ crucible at 1473 K as a surrogate for RE-rich ingot product from pyroprocessing. The produced ingot was sliced and used as a working electrode in LiCl-KCl-LaCl₃ salt. Only RE elements were then anodically dissolved by applying potential at - 1.7 V versus Ag/AgCl reference electrode. The RE-removed ingot product was used to produce UCl₃ via the reaction with NH4Cl in a sealed reactor.

• The Journal of Korean Medicine
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• v.31 no.5
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• pp.64-81
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• 2010

Objectives: The object of this study was to observe the suppressive effects of Yijintang-gamibang (YJGMB), Yijintang being traditionally used in the Korean Medicine for treating various digestive diseases, on the rat reflux esophagitis (RE) as compared with omeprazole, a well-known proton pump inhibitor. Methods: Three different dosages of YJGMB, 50, 100 and 200 mg/kg, were orally pretreated once a day for 28 days before pylorus and forestomach ligation. Seven groups of 8 rats each were used in the study. Six hrs after pylorus and forestomach ligation, changes to the stomach and esophagus lesion areas, gastric volumes, acid and pepsin outputs, invasive lesion percentages, fundic mucosa, esophageal submucosa and total thicknesses were measured by histomorphometry. The results were compared with omeprazole 10 and 30 mg/kg treated groups in which the effects on RE were already confirmed. Results: As results of pylorus and forestomach ligation, marked increases of esophageal and gastric mucosa lesion areas, gastric volumes, acid outputs, pepsin outputs were observed with histopathological changes of RE, such as hemorrhages, ulcerative lesions and edematous changes on the esophageal and fundic mucosa. However, these pylorus and forestomach ligation induced RE were dose-dependently inhibited by treatment of 50, 100 and 200 mg/kg of YJGMB. YJGMB 50 mg/kg showed similar suppressive effects as 30 mg/kg of omeprazole, but more favorable effects were observed as compared with omeprazole 10 mg/kg. Conclusion: The results suggest that YJGMB showed favorable suppressive effects on the RE induced by pylorus and forestomach ligation. It is therefore expected that YJGMB will show favorable effects on RE as corresponds to the suggestion of traditional Korean medicine. However, more detailed mechanism studies should be conducted in future with the screening of the biological active chemical compounds in herbs.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.255-255
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• 2016

Resistive random access memory (ReRAM)는 낮은 동작 전압, 빠른 동작 속도, 고집적화 등의 장점으로 인해 차세대 비휘발성 메모리 소자로써 많은 관심을 받고 있다. 최근에 ReRAM 절연막으로 NiOx, TiOx, AlOx TaOx, HfOx와 같은 binary metal oxide 물질들을 적용하는 연구가 활발히 진행되고 있다. 특히, HfOx는 안정적인 동작 특성을 나타낸다는 점에서 ReRAM 절연막 물질로 적합하다고 보고되고 있다. ReRAM 절연막을 형성할 때, 물리 기상 증착 방법 (PVD)이나 화학 기상 증착법 (CVD)과 같은 방법이 많이 이용된다. 이러한 증착 방법들은 고품질의 박막을 형성시킬 수 있는 장점이 있다. 하지만, 높은 온도에서의 공정과 고가의 진공 장비가 이용되기 때문에 경제적인 문제가 있으며, 기판 또는 금속에 플라즈마 손상으로 인한 문제가 발생할 수 있다. 따라서 이러한 문제점들을 개선하기 위해 용액 공정이 많은 관심을 받고 있다. 용액 공정은 공정과정이 간단할 뿐만 아니라 소자의 대면적화가 가능하고 공정온도가 낮으며 고가의 진공장비가 필요하지 않은 장점을 가진다. 따라서 본 연구에서는, 용액공정을 이용하여 HfOx 기반의 ReRAM 제작하였고 $25^{\circ}C$와 $85^{\circ}C$에서 ReRAM의 동작특성에 미치는 compliance current의 영향을 평가하였다. 실험 방법으로는, hafnium chloride (0.1 M)를 2-methoxyethanol에 충분히 용해시켜서 precursor를 제작하였다. 이후, p-type Si 기판 위에 습식산화를 통하여 300 nm 두께의 SiO2 절연층을 성장시킨 후, 하부전극을 형성하기 위해 electron beam evaporation을 이용하여 10/100 nm 두께의 Ti/Pt 전극을 증착하였다. 순차적으로, 제작된 산화물 precursor를 이용하여 Pt 위에 spin coating 방법으로 1000 rpm 10 초, 6000 rpm 30초의 조건으로 두께 35 nm의 HfOx 막을 증착하였다. 최종적으로, solvent 및 불순물을 제거하기 위해 $180^{\circ}C$의 온도에서 10 분 동안 열처리를 진행하였으며, 상부 전극을 형성하기 위해 electron beam evaporation을 이용하여 Ti와 Al을 각각 50 nm, 100 nm의 두께로 증착하였다. ReRAM 동작에서 compliance current가 미치는 영향을 평가하기 위하여 compliance current를 10mA에서 1mA까지 변화시키면서 측정한 결과, $25^{\circ}C$에서는 compliance current의 크기와 상관없이 일정한 메모리 윈도우와 우수한 endurance 특성을 얻는 것을 확인하였다. 한편, $85^{\circ}C$의 고온에서 측정한 경우에는 1mA의 compliance current를 적용하였을 때, $25^{\circ}C$에서 측정된 메모리 윈도우 크기를 비슷하게 유지하면서 더 우수한 endurance 특성을 얻는 것을 확인하였다. 결과적으로, 용액공정 방법으로 제작된 ReRAM을 측정하는데 있어서 compliance current를 줄이면 보다 우수한 endurance 특성을 얻을 수 있으며, ReRAM 소자의 전력소비감소에 효과적이라고 기대된다.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.215-220
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• 2002

Epoxy-coated re-bar was partly used to the structures and put to practical use, but were not economical and appeared to have defects such as the diminishing of long term bond strength between concrete. The study of polymer cement slurry coated re-bar was started in order to complement the defect of epoxy coated re-bar, and ever since the basic properties appeared to be excellent. But, study of bond properties embedded in concrete specimens was insufficient until now. This study attempts to examine the possibility of improving the bond strength of polymer cement slurry coated re-bar between concrete specimens in accordance with ACI Code and KS Code through pull-out test of 150mm$\times$150mm$\times$150mm substrates with polymer cement slurry coated re-bar having polymer cement ratios of 50%, 75% and 100%, coating thickness 250${\mu}{\textrm}{m}$, 450 ${\mu}{\textrm}{m}$ and with curing ages of 3, 7 and 28 days. High strength concrete was designed having a compressive strength of 500kgf/cm2 as specified. Practical bond length ranges of 55 and 85mm were applied to each of specimen. The bond strength of polymer cement slurry coated re-bar using St/BA-1 and St/BA-2 was compared to that of plain re-bar. The results of this study showed that the bond strength of 55mm bond length was much higher than that of 85mm bond length.

• Fashion & Textile Research Journal
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• v.24 no.2
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• pp.241-248
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• 2022

This study aims to provide basic data to suggest guidelines for re-education and work improvement of modelists based on the analysis of the current status of modelist work and education. A survey was conducted from January 4 to May 15, 2020, targeting 44 people working in pattern, pattern CAD, and grading in domestic apparel companies. Descriptive statistical analysis and frequency analysis using SPSS 25 were employed to analyze the status of work type, work difficulties, and re-education. For pattern production, the rate of using pattern CAD for business was high. It was found that companies mainly use YUKA CAD (63.8%), and branded companies use pattern CAD (100%). It was found that 3D CAD is mostly employed by vendors (88.9%), and CLO (90%) is mainly used. Regarding difficulties in pattern making, it was found that they experienced difficulties with stretchable materials owing to the amount of shrinkage and sagging of the fabric. The work problem was the lack of requisite working hours owing to the volume of work. Regarding future re-education, 63.6% of the total respondents indicated that they required a course related to pattern correction and material. Moreover, it was found that re-education was necessary to upgrade technology and acquire new knowledge, however, information on re-education was insufficient.