• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.301-307
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• 2017

The purpose of this study is to investigate the electrical properties of thick-film resistor (TFR) prepared from $CaO-ZnO-B_2O_3-Al_2O_3-SiO_2$ (CZBAS) glass containing $RuO_2$ particles. $RuO_2$-glass composite powder was made by mixing and melting oxide powders of constituents. For comparison, $RuO_2$ powder was simply mixed with glass powder. $RuO_2$-40wt% glass composite and mixture were dispersed in an organic binder to obtain printable resistor paste and then thick-film was formed by screen printing, followed by sintering at the range between $750^{\circ}C$ and $900^{\circ}C$ for 10 min with a heating rate of $50^{\circ}C/min$ in an ambient atmosphere. $RuO_2$-glass composite sample showed much higher resistance compared to the simple mixed sample. This could be attributed to the difference in conducting mechanism. After sintering at $850^{\circ}C$, temperature coefficient of resistance of composite sample was lower than that of simple-mixed sample. TFR with dense and homogeneous microstructure could be obtained by using $RuO_2$-glass composite powder.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.51-58
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• 2016

Concrete structure is a construction material with durability and cost-benefit, however the corrosion in embedded steel causes a critical problem in structural safety. This paper presents an evaluation of chloride resistance and pull-off performance with various corrosion level. For the work, OPC(Ordinary Portland Cement) concrete and GGBFS(Ground Granulated Blast Furnace Slag) concrete are prepared with normal steel. Artificially notch induced FRP Hybrid Bar is also prepared and embedded in OPC concrete and accelerated corrosion test is performed. Through the test, FRP Hybrid Bar with notch is evaluated to have insignificant effect on pull-off capacity when corroded steel shows only 21% level of pull-off capacity. Furthermore GGBFS concrete with normal steel shows over 70% level of pull-off capacity due to reduced corrosion currency.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.241.2-241.2
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• 2013

최근, 비정질 산화물 반도체 thin film transistor (TFT)는 수소화된 비정질 실리콘 TFT와 비교하여 높은 이동도와 큰 on/off 전류비, 낮은 구동 전압을 가짐으로써 빠른 속도가 요구되는 차세대 투명 디스플레이의 TFT로 많은 연구가 진행되고 있다. 한편, 기존의 MOSFET 제작 시 우수한 박막을 얻기 위해서는 $500^{\circ}C$ 이상의 높은 열처리 온도가 필수적이며 이는 유리 기판과 플라스틱 기판에 적용하는 것이 적합하지 않고 높은 온도에서 수 시간 동안 열처리를 수행해야 하므로 공정 시간 및 비용이 증가하게 된다는 단점이 있다. 따라서, 본 연구에서는 RF sputter를 이용하여 증착된 비정질 InGaZnO pesudo MOSFET 소자를 제작하였으며, thermal 열처리와 microwave 열처리 방식에 따른 전기적 특성을 비교 및 분석하고 각 열처리 방식의 열처리 온도 및 조건을 최적화하였다. P-type bulk silicon 위에 산화막이 100 nm 형성된 기판에 RF 스퍼터링을 이용하여 InGaZnO 분말을 각각 1:1:2mol% 조성비로 혼합하여 소결한 타겟을 사용하여 70 nm 두께의 InGaZnO를 증착하였다. 연속해서 Photolithography 공정과 BOE(30:1) 습식 식각 과정을 이용해 활성화 영역을 형성하여 소자를 제작하였다. 제작 된 소자는 pseudo MOSFET 구조이며, 프로브 탐침을 증착 된 채널층 표면에 직접 접촉시켜 소스와 드레인 역할을 대체하여 동작시킬 수 있어 전기적 특성을 간단하고 간략화된 공정과정으로 분석할 수 있는 장점이 있다. 열처리 조건으로는 thermal 열처리의 경우, furnace를 이용하여 각각 $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$에서 30분 동안 N2 가스 분위기에서 열처리를 실시하였고, microwave 열처리는 microwave를 이용하여 각각 400 W, 600 W, 800 W, 1000 W로 20분 동안 실시하였다. 그 결과, furnace를 이용하여 열처리한 소자와 비교하여 microwave 를 통해 열처리한 소자에서 subthreshold swing (SS), threshold voltage (Vth), mobility 등이 개선되는 것을 확인하였다. 따라서, microwave 열처리 공정은 향후 저온 공정을 요구하는 MOSFET 제작 시의 훌륭한 대안으로 사용 될 것으로 기대된다.

• Journal of Environmental Science International
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• v.27 no.12
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• pp.1299-1303
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• 2018

This study was conducted to evaluate the growth performance of broilers fed different levels of Hermetia illucens powder. A total of 400 broiler chicks (1-day old Arbor Acres) were fed commercial diets containing H. illucens powder at 0%, 0.1%, 0.5%, and 1% with four replicates (25 chicks per replicate), for 35 days. Weight gain in broilers fed diets containing different levels of H. illucens powder increased significantly at 28 and 35 days, compared with that of the control (p<0.05). However, feed intake and mortality showed no differences among the treatments as a function of time. At 21, 28, and 35 days, broilers fed different levels of H. illucens powder had lower feed conversion rates (p<0.05) than their counterparts fed the control diet. In conclusion, 0.5% H. illucens powder is the optimal level for improved weight gain and feed conversion.

• Journal of the Korean Geosynthetics Society
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• v.22 no.4
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• pp.51-61
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• 2023

In this study, in order to improve the fire resistance performance of structures in case of fire in buildings and structures, PVA fibers and the ZnO particles combined with mesoporous nano silica (MSNs) were mixed with cement mortar, and the specimen was exposed to a temperature range of 20~1100℃. Then the residual compressive strength and weight change rate were measured to determine whether the fire resistance performance changed. As a result of the study, it was found that mixing mesoporous nano silica and PVA fiber together did not contribute to improving the fire resistance performance of cement mortar. On the other hand, mixing 0.5% of mesoporous nano silica and 0.1 vol% of PVA fiber showed the best improvement test results, showing that it was advantageous for fire resistance performance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.540-548
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• 2015

This study examined the cultural characteristics and biological activities of fermented rice and amaranth with Bacillus subtilis KMKW4. These samples were made with various amounts of rice and amaranth [100:0 (R100), 90:10 (R90), 80:20 (R80), and 70:30 (R70)]. B. subtilis KMKW4 was used as starter for the fermentation, and its cultures at the lated logarithmic growth were inoculated for final concentration of 2% (v/v). Number of viable cells of fermented R80 (7.67 log CFU/mL) was greater than those of R100, R90, and R70 (7.48 log CFU/mL, 7.38 log CFU/mL, and 7.09 CFU/mL, respectively) during the fermentation period (120 h). Amylase activities of fermented R80 and R100 were 57.77 U/mL and 19.91 U/mL, respectively. Furthermore, amylase activities of fermented freeze-dried powders of R100 and R80 were 24.31 U/g and 9.12 U/g, respectively. Free sugar contents of R100 and R80 increased after fermentation, and that of R80 (5,454.15 mg/100 g) significantly increased compared to that of R100 (4,274.85 mg/100 g). The free amino acid content of R80 was higher than that of R100. DPPH and superoxide radical scavenging activities of 5 mg/mL of fermented freeze-dried powder (R80) were 44.21% and 89.76%, respectively. ACE inhibition rates and ${\alpha}$-glucosidase inhibitory activities were significantly higher in R80 than R100. This study suggested that fermentation of R80 might be a new potential source of antioxidant, anti-diabetic, and anti-hypertensive agents applicable to grain enzyme-containing foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.674-682
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• 2009

This study was designed to examine the effects of Compositae plants on plasma glucose and lipid levels in streptozotocin (STZ) induced diabetic rats. Sprague-Dawley rats were randomly assigned to 5 groups: normal, STZ-control and three experimental groups [Artemisia iwayomogi (A. iwayomogi), Atractylodes lancea (A. lancea), and Taraxacum mongolicum (T. mongolicum)]. Normal and STZ-control group were fed an AIN-93 diet and three experimental groups were each fed a modified diet containing 10% compositae powder for 4 weeks. The plasma glucose levels at 4 weeks of A. iwayomogi, A. lancea, and T. mongolicum groups were significantly lower than STZ-control group. The A. iwayomogi and A. lancea groups had significantly suppressed hypertrophy of liver and kidney. The hematocrit levels of A. lancea and T. mongolicum group were significantly lower than STZ-control groups. The total cholesterol and triglyceride levels and atherogenic index (AI) of A. lancea group were significantly lower than STZ-control group. Intake of Compositae plants may be effective in antihyperglycemia by lowering blood glucose levels. The A. iwayomogi, A. lancea, and T. mongolicum can be beneficial for the diabetic complications and damage from the lipid peroxidation.

• Journal of Nutrition and Health
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• v.51 no.4
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• pp.275-286
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• 2018

Purpose: Our previous study demonstrated that persimmon (Diospyros kaki Thumb.) at different stages of ripening provided different protective effects against high-fat/cholesterol diet (HFD)-induced dyslipidemia in rats. In this study, we compared the metabolites profile and gene expressions related to triglyceride (TG)/cholesterol metabolism in vitro and in vivo after treating with persimmon water extracts (PWE) or tannin-enriched persimmon concentrate (TEP). Methods: Primary and secondary metabolites in test materials were determined by GC-TOF/MS, UHPLC-LTQ-ESI-IT-MS/MS, and UPLC-Q-TOF-MS. The expression of genes related to TG and cholesterol metabolism were determined by RT-PCR both in HepG2 cells stimulated by oleic acid/palmitic acid and in liver tissues obtained from Wistar rats fed with HFD and PWE at 0, 150, 300, and 600 mg/d (experiment I) or TEP at 0, 7, 14, and 28 mg/d (experiment II) by oral gavage for 9 weeks. Results: PLS-DA analysis and heatmap analysis demonstrated significantly differential profiling of metabolites of PWE and TEP according to processing of persimmon powder. In vitro, TEP showed similar hypolipidemic effects as PWE, but significantly enhanced hypocholesterolemic effects compared to PWE in sterol regulatory element-binding protein 2 (SREBP2), HMG-CoA reductase (HMGCR), proprotein convertase subtilisin/kexin type 9 (PCSK9), cholesterol $7{\alpha}-hydroxylase$ (CYP7A1), and low density lipoprotein receptor (LDLR) gene expression. Consistently, TEP and PWE showed similar hypolipidemic capacity in vivo, but significantly enhanced hypocholesterolemic capacity in terms of SREBP2, HMGCR, and bile salt export pump (BSEP) gene expression. Conclusion: These results suggest that column extraction after hot water extraction may be a good strategy to enhance tannins and long-chain fatty acid amides, which might cause stimulation of hypocholesterolemic actions through downregulation of cholesterol biosynthesis gene expression and upregulation of LDL receptor gene expression.

• Journal of the Korean Society of Food Culture
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• v.21 no.3
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• pp.297-302
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• 2006

This study has examined the physicochemical properties of the Pleurotus eryngii, including their proximate components, amount mineral content, total dietary fiber, total sugar, reducing sugar and free sugar. Additionally, it measured the P. egii ethanol extracts and the total amounts of polyphenol compounds as well as its electron donating ability (EDA) of the substance fraction (SF). The P. eryngii powder's moisture content was 9.0% and each of the other element content such as carbohydrate, crude protein, crude ash and crude fat was found to be 63.06%, 20.70%, 5.20% and 2.0% respectively. Potassium (K) was shown to be the greatest inorganic content and manganese (Mn) was the lowest. Furthermore fructose, galactose, glucose lactose and maltose free sugar content was found in this order. 387 mg% of the total amounts of polyphenol was found in the P. eryngii whole body ethanol extract, 158 mg% in the stipe extract, 593 mg% in the pileus extract and 607 mg% in the substance fraction (SF). Electron donating ability (EDA) was highest at 91.12% in the whole body extract and lowest at 62.90% in the stipe extract. Additionally, the EDA for substance fraction (SF) 0.02%-0.1% was found to be 57.78-77.33%, which was lower than the 0.02%-tocopherol (93.92%) and BHT (96.72%). From these results, it can be assumed that P. eryngii offers superior antioxidative effects with its high content of fiber, inorganic materials and total amounts of polyphenol as well as high electron donating ability (EDA), thereby making it ideal for use in functional foods and industrial materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.862-868
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• 2005

Korean mountain ginseng roots were freeze-dried at $-70^{\circ}C$ and extracted by different extracting solution conditions to investigate chemical compositions of extracts. The soluble solid content of the extract from $7.04\~13.45\%\;and\;50\%$ EtOH and MeOH extracts were higher than those of other extracts. $100\%\;water\;and\;90\%$ EtOH extracts gave the highest Brix with $19.98\%$\;and\;19.65\%$, respectively. pH of the extracts were ranged from $5.82\~6.60$. Browning color at 470 nm of the extract were high value in 50$\%$ EtOH extract. In case of Hunter's color value, L value of extract was higher in $100\%$ water extract (21.28) than EtOH extract $(17.18\~21.02)$, a and b values of extract were the highest in $100\%$ water (-0.12) and $90\%$ MeOH extract (1.34). The contents of free sugars in the EtOH extract were increased with the ethanol concentration. Sucrose contents of $90\%$ EtOH and MeOH extracts were 6,159 mg/100 g and 5,238 mg/100 g. Major organic acids of the extract were citric and malic acids. Major free amino acids of the extract were L-arginine, L-proline, $\gamma$ -amino-n-butyric acid, alanine and aspartic acid. The highest ginsenoside content was shown to be about $10.50\%\;in\;90\%$ MeOH extract. Major minerals of extract were P, K, Na, Mg and Ca.