• 한국세라믹학회지
• /
• 제48권1호
• /
• pp.1-5
• /
• 2011

Silicon carbide (SiC) has recently drawn an enormous industrial interest because of its useful mechanical properties such as thermal resistance, abrasion resistance and thermal conductivity at high temperature. RF Thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) has been utilized for synthesis of high purity SiC powder from cheap inorganic solution (Tetraethyl Orthosilicate, TEOS). It is found that the powders by thermal plasma consist of SiC with free carbon and amorphous silica ($SiO_2$) and, by thermal treatment and HF treatment, the impurities are driven off resulting high purity SiC nano-powder. The synthesized SiC powder lies below 30 nm and its properties such microstructure, phase composition, specific surface area and free carbon content have been characterized by X-ay diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric (TG) and Brunauer-Emmett-Teller (BET).

• 한국수소및신에너지학회논문집
• /
• 제22권4호
• /
• pp.458-464
• /
• 2011

Recently, one of the hydrogen production methods has attracted using dense metallic membrane. It has high hydrogen permeation and selectivity which hardly could adopt industrial product because of high cost, hydrogen embrittlment and thermal stability. Meanwhile, vanadium has high hydrogen solubility and it use to instead of Pd-Ag amorphous membrane. Aluminum carried out blocking hydrogen diffusion on grain boundary therefore protecting hydrogen embrittlement. Most of dense metallic membrane is solution diffusion mechanism. The solution diffusion mechanism was very similar hydrogen storing steps such as steps of metal hydride. Thus, V-Al composites were fabricated to use hydrogen induced mechanical alloying. The fabricated V-Al composites were characterized by XRD, SEM, EDS and simultaneous TG/DSC analyses. The hydrogenation behaviors were evaluated using a Sievert's type automatic PCT apparatus. The hydrogenation behaviors of V-Al composites was evaluated too low hydrogen stored capacity and fast hydrogenation kinetics. In PCI results, V-Al composites had low hydrogen solubility, in spite of that, hydrogen kinetics was calculated very fast and hydrogen absorption/desorption contents were same capacity.

• Journal of Pharmaceutical Investigation
• /
• 제26권3호
• /
• pp.215-219
• /
• 1996

Active component was sought among three herb medicines, which are used in combination as a traditional medicine prescribed for patients with hyperlipidemia related diseases. Antihyperlipidemic effect of this remedy has previously been shown model by the authors on the animal model. Hyperlipidemia was induced on male Wistar rats by keeping them on high lipid diet for one week, as previously described by the authors. Blood lipid profile was verified on these rats by measuring total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL) and low density lipoprotein (LDL). Then, the diet was changed to normal. At the same time, methanol extracts of Scutellaris baicalensis Georg.(radix), Coptidis japonica Makino(rhizoma) or Rhei koreanum Nakai(rhizoma) were given on daily basis, and changes in the blood lipid profile were monitored for 4 weeks. Methanol extract of Scutellaris baicalensis Georg. significantly reduced the TC value, implying the in vivo antihyperlipidemic effect.

• 한국세라믹학회지
• /
• 제49권6호
• /
• pp.523-527
• /
• 2012

Silicon carbide (SiC) has recently drawn an enormous amount of industrial interest due to its useful mechanical properties, such as its thermal resistance, abrasion resistance and thermal conductivity at high temperatures. In this study, RF thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) was utilized for the synthesis of high-purity SiC powder from an organic precursor (hexamethyldisilazane, vinyltrimethoxysilane). It was found that the SiC powders obtained by the RF thermal plasma treatment included free carbon and amorphous silica ($SiO_2$). The SiC powders were further purified by a thermal treatment and a HF treatment, resulting in high-purity SiC nano-powder. The particle diameter of the synthesized SiC powder was less than 30 nm. Detailed properties of the microstructure, phase composition, and free carbon content were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), a thermogravimetric (TG) analysis, according to the and Brunauer-Emmett-Teller (BET) specific surface area from N2 isotherms at 77 K.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 가을 학술논문 발표대회
• /
• pp.133-134
• /
• 2021

Limestone-calcined clay-Cement (LC3) concrete provides a solution for sustainability, durability, and profitability of concrete industry. This study shows experimental studies of the macro properties (residual compressive strength), the meso properties (mesoscopic images), and micro properties (thermogravimetric (TG) analysis, X-ray powder diffraction (XRD), FTIR spectra, Raman spectra, Mercury intrusion porosimetry, and SEM) of LC3 paste with various mixtures and at high elevated temperatures (20 ℃, 300 ℃, 550 ℃ and 900 ℃). We find (1) Regarding to macro properties, LC3 cementitious materials are at a disadvantage in compressive strength when the temperature is higher than 300 ℃. (2) Regarding to meso properties, when the temperature reached 550 ℃, all samples generated more meso cracks. (3) Regarding to micro properties, first, as the substitution amount increases, its CH content decreases significantly; second, at 900 ℃, for samples with calcined clay, a large amount of gehlenite crystalline phase was found; third, at elevated temperatures (20 ℃, 300 ℃, 550 ℃ and 900 ℃), there is a linear relationship between the residual compressive strength and the cumulative pore volume; fourth, at 900 ℃, a large amount of dicalcium silicate was generated, and damage cracks were more pronounced. The experimental results of this study are valuable of material design of fire resistance of LC3 concrete.

• 한국식품영양과학회지
• /
• 제43권4호
• /
• pp.491-497
• /
• 2014

본 연구는 고콜레스테롤 식이를 급여한 마우스의 지질대사에 알긴산 올리고당이 미치는 영향을 조사하였다. 실험동물은 4주령 된 수컷 apoE 마우스를 사용하였으며, 정상군, 고콜레스테롤 식이대조군, 알긴산 올리고당 5%와 10% 첨가군으로 나누어 6주간 급여하였다. 실험식이는 AIN-93G 식이를 기본으로 하여 콜레스테롤(1%, w/w)을 혼합하였으며, 알긴산 올리고당을 각각 5%와 10% 수준으로 혼합하였다. 실험기간 동안 증체량은 고콜레스테롤 식이대조군에 비해 알긴산 올리고당 10% 첨가군이 약 7.6% 유의적으로 감소하였다(P<0.05). 장기조직 중 신장 주변지방과 부고환지방의 무게는 고콜레스테롤 식이대조군이 정상군에 비해 각각 42.6%, 27.6% 유의적으로 증가하였다(P<0.05). 반면 알긴산 올리고당 첨가군은 신장 주변지방과 부고환지방 무게가 고콜레스테롤 식이대조군보다 2배 이상 유의적으로 감소하였다(P<0.05). 고콜레스테롤 섭취는 혈청 중 총 콜레스테롤, 중성지방, LDL-콜레스테롤 수준을 정상군보다 각각 16%, 12%, 47.1% 유의적으로 증가시켰으며, 반면에 알긴산 올리고당 10%를 섭취한 경우 고콜레스테롤 식이대조군보다 각각 57.5%, 51.4%, 82.9% 유의적으로 감소시켰다 (P<0.05). 혈청 HDL-콜레스테롤 함량은 실험군간 유의적 차이는 크게 나타나지 않았으나, 전체 콜레스테롤에 대한 HDL-콜레스테롤 비율에서 알긴산 올리고당 첨가군이 유의적으로 높았다(P<0.05). 간 조직 내 지질 수준은 고콜레스테롤을 섭취했을 경우 정상군에 비해 유의적으로 증가하였으나, 알긴산 올리고당 10%를 섭취했을 때 고콜레스테롤 식이대조군보다 총 콜레스테롤 함량은 3배 이상, 중성지방 함량은 33.5% 유의적으로 감소하였다(P<0.05). 고콜레스테롤 식이군에서 나타난 분변 내 총 콜레스테롤 함량은 알긴산 올리고당 10% 첨가군에서 정상군보다 21% 유의적으로 증가하였다(P<0.05). 이상의 실험 결과 고콜레스테롤 식이와 알긴산 올리고당을 함께 섭취한 마우스는 체중 감량과 장기 내 지방의 중량을 감소시켜 비만 예방효과가 있고, 혈액, 간지질 및 분변 지질 수준의 개선 효과가 높아 지질대사와 관련된 만성질환 예방에 효과가 있을 것으로 기대된다.

• Nutrition Research and Practice
• /
• 제9권6호
• /
• pp.619-627
• /
• 2015

BACKGROUND/OBJECTIVES: Colitis is a serious health problem, and chronic obesity is associated with the progression of colitis. The aim of this study was to determine the effects of natural raw meal (NRM) on high-fat diet (HFD, 45%) and dextran sulfate sodium (DSS, 2% w/v)-induced colitis in C57BL/6J mice. MATERIALS/METHODS: Body weight, colon length, and colon weight-to-length ratio, were measured directly. Serum levels of obesity-related biomarkers, triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL), insulin, leptin, and adiponectin were determined using commercial kits. Serum levels of pro-inflammatory cytokines including tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$, and IL-6 were detected using a commercial ELISA kit. Histological study was performed using a hematoxylin and eosin (H&E) staining assay. Colonic mRNA expressions of TNF-${\alpha}$, IL-$1{\beta}$, IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were determined by RT-PCR assay. RESULTS: Body weight and obesity-related biomarkers (TG, TC, LDL, HDL, insulin, leptin, and adiponectin) were regulated and obesity was prevented in NRM treated mice. NRM significantly suppressed colon shortening and reduced colon weight-to-length ratio in HFD+DSS induced colitis in C57BL/6J mice (P < 0.05). Histological observations suggested that NRM reduced edema, mucosal damage, and the loss of crypts induced by HFD and DSS. In addition, NRM decreased the serum levels of pro-inflammatory cytokines, TNF-${\alpha}$, IL-$1{\beta}$, and IL-6 and inhibited the mRNA expressions of these cytokines, and iNOS and COX-2 in colon mucosa (P < 0.05). CONCLUSION: The results suggest that NRM has an anti-inflammatory effect against HFD and DSS-induced colitis in mice, and that these effects are due to the amelioration of HFD and/or DSS-induced inflammatory reactions.

• 한방비만학회지
• /
• 제9권2호
• /
• pp.33-45
• /
• 2009

Objectives This study was performed to evaluate the relation between hair tissue mineral elements(HTME) and Heart rate variability(HRV) of the metabolic syndrome(MS). Methods 89 persons(41-69 ages) who visited Oriental hospital for medical examination were divided MS group(n=22) and control group(n=67). HTME and HRV were compared, and were analyzed correlation with five contents of the MS. Results (1) In total subjects, waist circumference had a positive correlation with Pb. Blood pressure had a negative correlation with Mg. High density lipoprotein cholesterol(HDL-chol) had a negative correlation with Pb, Sb and K, while positive correlation with Ca/K. Triglyceride(TG) had a negative correlation with Mg and Na/K, while positive correlation with K and Ca/Mg. (2) In total subjects, TG and fasting blood sugar(FBS) had negative correlation with high frequency(HF), while positive correlation with low frequency/high frequency ratio(LF/HF). (3) In MS group, most of the level of toxic minerals were higher, and the level of major nutritional minerals were lower, but there were no statistical signficance. In two groups, there is no contrast between the correlations of the MS contents and HTME. (4) In MS group, HF was significantly lower and LF/HF was higher than normal group. LF/HF had a negative correlation with waist circumference in MS group, while positive correlation in normal group. (5) In total subjects, TP had a positive correlation with Mg. In two groups, there is no contrast between the correlations of the MS contents and HRV. However LF/HF had a positive correlation with Na in MS group, TP and LF had negative correlation with Ca, while RMSSD and HF had negative correlation with Cu in normal group. Conclusion These results may suggest that HTME and HRV are useful in diagnosing and preventing the metabolic syndrome.

• 한방재활의학과학회지
• /
• 제24권2호
• /
• pp.1-13
• /
• 2014

Objectives The purpose of this study was to investigate the effects of Cheunggihwadamhwan (CGHDH) extract on lowering lipid, antioxidation and production of proinflammatory cytokines in rats fed on high fat diet. Methods 40 Male Sprague-Dawley rats were fed on high fat diet for 8 weeks and 32 rats (above 400 g) were randomly divided into 4 groups (8 mice in each group) : control group, 100 mg/Kg CGHDH group, 200 mg/Kg CGHDH group, 300 mg/Kg CGHDH group. We fed a control group of rats a basal diet and administered normal saline(100 mg/kg, 1 time/1 day) for 4 weeks. And We fed each experimental group of rats basal diet and administered an extract of Cheunggihwadamhwan extracts (100 mg/kg, 200 mg/kg, 300 mg/kg, 1 time/1 day) for 4 weeks. At the end of the experiment, the rats were sacrificed to determine their chemical composition. We measured lipid in plasma and liver, concentration of proinflammatory cytokines, antioxidative activity and gene expression. The gene expression level was investigated by the way of reverse transcription-polymerase chain reaction (RT-PCR). Results 1. Concentration of plasma FFA, plasma TG, plasma total cholesterol and plasma LDL-cholesterol showed a significant decrement in Cheunggihwadamhwan groups. However, concentration of plasma HDL-cholesterol showed a significant increment in 200, 300 mg/kg Cheunggihwadamhwan groups. 2. Concentration of liver total cholesterol and liver TG showed a significant decrement in Cheunggihwadamhwan groups. 3. Concentration of plasma TBARS showed a significant decrement in all Cheunggihwadamhwan groups. Concentration of liver TBARS showed a significant decrement in 200, 300 mg/kg Cheunggihwadamhwan groups. Concentration of liver GSH-Px, SOD and CAT showed a tendency to decrease in all Cheunggihwadamhwan groups. 4. Concentration of plasma IL-$1{\beta}$, plasma IL-6, TNF-$\alpha$ and NO, showed a tendency to decrease in all Cheunggihwadamhwan groups. Concentration of plasma IL-10 showed a tendency to increase in all Cheunggihwadamhwan groups. 5. In the analysis of reverse transcription-polymerase chain reaction (RT-PCR), the gene expression of Apo-B and Apo-E in the Cheunggihwadamhwan groups showed a low expression than that of control group. The ratio of Apo-B expression per $\beta$-actin expression in the showed a significant decrement in all Cheunggihwadamhwan groups. The ratio of Apo-E expression per $\beta$-actin expression in the showed a significant decrement in 300 mg/kg Cheunggihwadamhwan groups. Conclusions According to this study, the extract of Cheunggihwadamhwan showed a positive effect of lowering lipid, antioxidation and a control of producing proinflammatory cytokines.

• 마이크로전자및패키징학회지
• /
• 제21권1호
• /
• pp.31-39
• /
• 2014

최근 모바일 응용 제품에 사용되는 반도체 패키지는 고밀도, 초소형 및 다기능을 요구하고 있다. 기존의 웨이퍼 레벨 패키지(wafer level package, WLP)는 fan-in 형태로, I/O 단자가 많은 칩에 사용하기에는 한계가 있다. 따라서 팬 아웃 웨이퍼 레벨 패키지(fan-out wafer level package, FOWLP)가 새로운 기술로 부각되고 있다. FOWLP에서 가장 심각한 문제 중의 하나는 휨(warpage)의 발생으로, 이는 FOWLP의 두께가 기존 패키지에 비하여 얇고, 다이 레벨 패키지 보다 휨의 크기가 매우 크기 때문이다. 휨의 발생은 후속 공정의 수율 및 웨이퍼 핸들링에 영향을 미친다. 본 연구에서는 FOWLP의 휨의 특성과 휨에 영향을 미치는 주요 인자에 대해서 수치해석을 이용하여 분석하였다. 휨을 최소화하기 위하여 여러 종류의 epoxy mold compound (EMC) 및 캐리어 재질을 사용하였을 경우에 대해서 휨의 크기를 비교하였다. 또한 FOWLP의 주요 공정인 EMC 몰딩 후, 그리고 캐리어 분리(detachment) 공정 후의 휨의 크기를 각각 해석하였다. 해석 결과, EMC 몰딩 후에 발생한 휨에 가장 영향을 미치는 인자는 EMC의 CTE이며, EMC의 CTE를 낮추거나 Tg(유리천이온도)를 높임으로서 휨을 감소시킬 수 있다. 캐리어 재질로는 Alloy42 재질이 가장 낮은 휨을 보였으며, 따라서 가격, 산화 문제, 열전달 문제를 고려하여 볼 때 Alloy 42 혹은 SUS 재질이 캐리어로서 적합할 것으로 판단된다.