• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.297-298
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• 2019

본 논문에서는 인덕터와 커패시터(LC)를 이용한 새로운 전압 밸런서(VB)를 제안한다. 제안한 VB는 하프-브리지 및 Neutral-Point-Clamped 구조처럼 이중 출력을 가진 Dual-Active-Bridge (DAB) 컨버터에 적용될 수 있다. 제안한 VB는 추가적인 스위칭 소자를 사용하지 않더라도 출력 부하 조건에 관계없이 출력 전압 평형을 유지할 수 있다. 제안한 VB를 사용할 때, 변압기와 출력의 중성점 사이에 LC가 추가되지만, 컨버터의 PWM 방식과 동작은 기존과 대부분 동일하다. 따라서, 제안한 VB를 사용하는 이중 출력 DAB 컨버터는 기존 이중 출력 DAB 컨버터의 장점을 대부분 유지한 상태로 출력 전압 평형을 달성할 수 있다. 3 kW 시제품을 제작하여 제안한 VB의 성능을 검증하였다.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.22-22
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• 2003

원자로에서 핵분열에 의해 생성된 고에너지 중성자는 감속재를 통해 열평형에 의해 에너지가 낮춰져 통계적 분포, 즉 Maxwell-Boltzman 운동에 따른 에너지 스펙트림을 갖게 된다. 중성자 산란장치는 통상 단색빔을 이용하므로 단색기(monochiomator)를 통해 이 분포에서 특정 파장의 중성자빔을 인출, 즉 단색화한다. 이때 단색기는 각각의 중성자 산란장치에 사용할 수 있는 특정 파장의 중성자빔을 인출하면서도, 파장의 퍼짐을 적절하게 조절하여 높은 중성자속(neutron flux)을 가지며 분해능도 또한 좋아야 한다. 전통적으로 많이 사용하는 단색화 방법은 결정의 내부결함을 유도하여 만든 모자익(mosaic) 결정을 이용하는 것이다. 이 방법은 특정 파장을 얻으면서도 좋은 분해능과 높은 중성자속을 갖는 모자익 결정을 만들기가 어렵고, 한번 결정된 단색기의 특성을 바꿀 수 없는 단점이 있다. 1980년대부터 몇몇 그룹이 거의 완전하게 성장된 단결정 슬랩을 미세하게 구부려서 탄성변형을 주어 effective 모자익 구조를 발생시킨 '구부린 완전결정(bent perfect crystal, BPC)' 단색기를 개발하여 특정 목적에 활용하는 시도를 하였다. BPC 단색기는 단색화된 중성자빔을 집속(focusing)할 수 있으며, 결정의 구부림 정도를 조절하고 배치 기하를 바꿈으로써 다양한 특성을 갖는 단색빔을 얻을 수 있는 장점이 있다. 이렇게 단색기의 기하학적 변수를 조절함으로써 회절빔의 집속도와 분해능을 조절할 수 있어서 잔류응력 측정이나 단결정 회절 및 집합조직 측정장치 등에 적용할 수 있다. 본 연구에서는 BPC 단색기의 원리와 여러 배치기하에 따른 빔의 특성을 소개하고자 한다.빔이 시료와 상호 작용하는 면적과 상호작용하지 않을 때의 빔을 회절모드에서 faraday cup으로 측정한 빔전류로 부터 계산하였다. Gibbsite에 대한 전자빔 조사 시 1분 이내에 급격한 Hydroxyl Ion(OH-)의 이탈로 인해 Cibbsite의 구조는 거시적 비정질화가 되며 시간증가에 따라 χ-alumina → ν-alumina → σ-alumina or δ-alumina의 순으로 상전이를 겪는다. 전자빔 조사 시 관찰된 회절자료의 가시적 변화를 통해 illumination angle 1.25mrad(Dose rate : 334 × 10³ e/sup -//sec·n㎡)일 경우 약 3초 이내에 비정질화가 시작됨을 알 수 있었고 이는 약 1 × 10/sup 6/ e/sup -//sec·n㎡ 의 전자선량에 해당되며 이를 기준으로 각각의 illumination angle에 대한 임계전자선량을 평가할 수 있었다. 실질적으로 Cibbsite와 같은 무기수화물의 직접가열실험 시 전자빔 조사에 의해 야기되는 상전이 영향을 배제하고 실험을 수행하려면 illumination angle 0.2mrad (Dose rate : 8000 e/sup -//sec·n㎡)이하로 관찰하고 기록되어야 함을 본 자료로부터 알 수 있었다.운동횟수에 의한 영향으로써 운동시간을 1일 6시간으로 설정하여, 운동횟수를 결정하기 위하여 오전, 오후에 각 3시간씩 운동시키는 방법과 오전부터 6시간동안 운동시키는 두 방법을 이용하여 품질을 비교하였다. 각 조건에 따라 운동시킨 참돔의 수분함량을 나타낸 것으로, 2회(오전 3시간, 오후 3시간)에 나누어서 운동시키기 위한 육의 수분함량은 73.37±2.02%를 나타냈으며, 1회(6시간 운

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1079-1085
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• 2006

Purpose : The purpose of this study was to evaluate factors affecting hematologic recovery and infection in high-dose chemotherapy(HDCT) and autologous stem cell transplantation(ASCT) in patients with high-risk solid tumor. Methods : From January 2004 to December 2005, 72 HDCTs and ASCTs were applied to children with high-risk solid tumor at Samsung Medical Center. Medical records of these 72 HDCTs and ASCTs were retrospectively analyzed. Results : The single most powerful predictor of neutrophil and platelet recovery was the number of transplanted $CD34^+$ cells. The duration of high fever was significantly longer in young patients, in patients treated with total body irradiation and/or thiotepa, and in patients transplanted with lower $CD34^+$ cell dose(<$2{\times}10^6/kg$). However, the difference in the duration of high fever according to the number of $CD34^+$ cells was not clinically significant. Conclusion : Findings in this study suggest that HDCT and ASCT with low $CD34^+$ cell dose is clinically feasible despite delayed hematologic recovery, especially at a dose >$1{\times}10^6/kg$ per transplantation. Therefore, it is important not to defer the appropriate time for HDCT for an additional collection of hematopoietic stem cells if the number of collected $CD34^+$ cells is >$1{\times}10^6/kg$ per transplantation.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.39-46
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• 2015

Objective of this research was to investigate the influence of compositions and concentrations of fertilizer solutions on the vegetative growth and nutrient uptake of 'Seolhyang' strawberry. To achieve this, the solutions of acid fertilizer (AF), neutral fertilizer (NF), and basic fertilizer (BF) were prepared at concentrations of 100 or $200mg{\cdot}L^{-1}$ based on N and applied during the 100 days after transplanting. The changes in chemical properties of the soil solution were analysed every two weeks, and crop growth measurements as well as tissue analyses for mineral contents were conducted 100 days after fertilization. The growth was the highest in the treatments with BF, followed by those with NF and AF. The heaviest fresh and dry weights among treatments were 151.3 and 37.8 g, respectively, with BF $200mg{\cdot}L^{-1}$. In terms of tissue nutrient contents, the highest N, P and Na contents, of 3.08, 0.54, and 0.10%, respectively, were observed in the treatment with NF $200mg{\cdot}L^{-1}$. The highest K content was 2.83%, in the treatment with AF $200mg{\cdot}L^{-1}$, while the highest Ca and Mg were 0.98 and 0.42%, respectively, in BF $100mg{\cdot}L^{-1}$. The AF treatments had higher tissue Fe, Mn, Zn, and Cu contents compared to those of NF or BF when fertilizer concentrations were controlled to equal. During the 100 days after fertilization, the highest and lowest pH in soil solution of root media among all treatments tested were 6.67 in BF $100mg{\cdot}L^{-1}$ and 4.69 in AF $200mg{\cdot}L^{-1}$, respectively. The highest and lowest ECs were $5.132dS{\cdot}m^{-1}$ in BF $200mg{\cdot}L^{-1}$ and $1.448dS{\cdot}m^{-1}$ in BF $100mg{\cdot}L^{-1}$, respectively. For the concentrations of macronutrients in the soil solution of root media, the AF $200mg{\cdot}L^{-1}$ treatment gave the highest $NH_4$ concentrations followed by NF $200mg{\cdot}L^{-1}$ and AF $100mg{\cdot}L^{-1}$. The K concentrations in all treatments rose gradually after day 42 in all treatments. When fertilizer concentrations were controlled to equal, the highest Ca and Mg concentrations were observed in AF followed by NF and BF until day 84 in fertilization. The BF treatments produced the highest $NO_3$ concentrations, followed by NF and AF. The trends in the change of $PO_4$ concentration were similar in all treatments. The $SO_4$ concentrations were higher in treatments with AF than those with NF or BF until day 70 in fertilization. These results indicate that compositions of fertilizer solution should to be modified to contain more alkali nutrients when 'Seolhyang' strawberry is cultivated through inert media and nutri-culture systems.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1595-1603
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• 2010

The present study was conducted to investigate the effect of dietary grape pomace on lipid metabolism and hepatic morphology of rats fed a high fat diet. The high fat diet contained additional 15% lard to AIN 93-based diet. Male Sprague-Dawley rats were fed experimental diets containing 5% grape pomace for 4 weeks. Serum activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) were not changed by high fat and grape pomace feeding. Serum concentration of triglyceride in rats fed a high fat diet was decreased significantly by dietary grape pomace. Hepatic concentrations of total lipid, total cholesterol and triglyceride were reduced in grape pomace groups with a high fat diet. Fecal concentrations of total cholesterol and triglyceride were increased in grape pomace groups with a high fat diet. The fecal content of coprostanol was not different among the groups. Dietary grape pomace increased the fecal excretion of cholesterol and coprostanone in rats fed a high fat diet. The fecal excretion of bile acid was not affected by feeding grape pomace in rats fed a high fat diet. Light micrographs of liver tissue revealed lipid droplets were increased by a high fat diet, but dietary supplementation of grape pomace tended to alleviate such changes.

• Economic and Environmental Geology
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• v.35 no.4
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• pp.325-337
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• 2002

We examined the contamination of stream water and stream sediments by heavy metal elements with respect to distance from the abandoned Backun Au-Ag-Cu mine. High contents of heavy metals (Pb, Zn, Cu, Cd, Mn, and Fe) and aluminum in the waters connected with mining and associated deposits (dumps, tailings) reduce water quality. In the mining area, Ca and SO$_4$ are predominant cation and anion. The mining water is Ca-SO$_4$ type and is enriched in heavy metals resulted from the weathering of sulfide minerals. This mine drainage water is weakly acid or neutral (pH; 6.5-7.1) because of neutralizing effect by other alkali and alkaline earth elements. The effluent from the mine adit is also weakly acid or neutral, and contains elevated concentrations of most elements due to reactions with ore and gangue minerals in the deposit. The concentration of ions in the Backun mining water is high in the mine adit drainage water and steeply decreased award to down stream. Buffering process can be reasonably considered as a partial natural control of pollution, since the ion concentration becomes lower and the pH value becomes neutralized. In order to evaluate mobility and bioavailability of metals, sequential extraction was used for stream sediments into five operationally defined groups: exchangeable, bound to carbonates, bound to FeMn oxide, bound to organic matter, and residual. The residual fraction was the most abundant pool for Cu(2l-92%), Zn(28-89%) and Pb(23-94%). Almost sediments are low concentrated with Cd(2.7-52.8 mg/kg) than any other elements. But Cd dominate with non stable fraction (68-97%). Upper stream sediments are contaminated with Pb, and down area sediments are enriched with Zn. It is indicate high mobility of Zn and Cd.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.672-677
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• 2012

Lipids in microalgal biomass were recovered by using pyrolysis method. The pyrolysis experiments of two Chlorella sp. KR-1 samples, which have triglyceride contents of 10.8% and 36.5%, respectively were carried out at $600^{\circ}C$ to investigate the effects of lipid contents in the cells on the reaction characteristics. The conversion and liquid yield of the lipid-rich sample were higher than those of the lipid-lean sample since its carbon to hydrogen ratio was low. There were low molecular weight organic acids, ketones, aldehydes and alcohols in the liquid products from both KR-1 samples, but the pyrolysis oil of the lipid-rich sample was abundant in free fatty acids, particularly palmitic acid, oleic acid and stearic acid while the content of nitrogen containing organic compounds was low. The microalgal pyrolysis oil had two layers composed of the light hydrophobic fraction and the heavy hydrophilic fraction. The light fraction might be originated from triglycerides and the heavy fraction might be from carbohydrates and proteins. In the light fraction of the liquid products, there were considerable linear alkanes such as pentadecane and heptadecane as well as free fatty acids, implying that deoxygenation reaction including decarboxylation was occurred during the pyrolysis. The yield of the liquid products from the pyrolysis of the KR-1 sample having triglyceride content of 36.5% was 56.9% and the light fraction in the liquid products was 68.2%. Also more than 80% of the light fraction was free fatty acids and pure hydrocarbons, thus showing that most triglycerides could be extracted in the form of suitable raw materials for biofuels.

• Korean Journal of Food Science and Technology
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• v.17 no.1
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• pp.15-21
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• 1985

This study was designed to elucidate the lipid and its fatty acid composition in various tissues of cat fish, Parasilurus asotus. The free lipid contents in meat, skin and viscera were 5.62%, 26.34% and 19.27%, whereas the bound lipid contents in those tissues were 2.34%, 2.30% and 19.27%, respectively. The neutral lipid contents in free lipid were 5 times higher than those in bound lipid, while the phospholipid contents in bound lipid were 4 times higher than those in free lipid. The neutral lipid was mainly composed of triglyceride (79.84%-99.86%) in free lipid, and esterified sterol & hydrocarbon (55.12-64.33%) in bound lipid. The phospholipid was mainly composed of phosphatidyl choline (52.38-69.98%) and phosphatidyl ethanolamine (24.09-40.48%) in free lipid, and phosphatidyl choline (53.03-58.54%) and phosphatidyl ethamolamine (13.80-19.23%) in bound lipid. The major fatty acids of polar lipid in free and bound lipids were C16:0 (28.37%, 21.99%), C18:1 (12.01%, 11.52%), C18:2 (17.93%, 14.12%) and C22:6 (17.22%, 20.63%), and those of nonpolar lipid in free and bound lipids were C16:0 (14.81%, 18.94%), C18: 1 (25.93%, 10.89%) and C22:6 (9.95%,23.44%), respectively. The total essential fatty acid (TEFA) content in skin was slightly higher than that in meat. In both polar and nonpolar lipids in meat ${\omega}3-HUFA$ contents of polar lipid were 1.5-2.0 times higher than nonpolar lipid and also ${\omega}3-HUFA$ content of bound lipid was slightly higher than that of free lipid. There were significant differences in the lipid classification and its fatty acid composition between free and bound lipids and/or in various tissues.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.686-696
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• 1997

This is a cross-sectional study to evaluate the serum lipid levels of children living in Pusan in 1996. The distribution of age is from 2 years old to 12 years old. In female children mean total cholesterol is $171.4{\pm}26.2mg/dl$, triglyceride is $104.7{\pm}50.6mg/dl$, HDL-cholesterol is $54.4{\pm}14.8mg/dl$, and LDL-cholesterol is $95.4{\pm}32.9mg/dl$. In male children mean total cholesterol is $167.9{\pm}25.2mg/dl$, triglyceride is $6{\pm}45.5mg/dl$, HDL-cholesterol is $55.4{\pm}11.7mg/dl$, and LDL-cholesterol is $94.4{\pm}23.6mg/dl$. The percentile of serum lipid levels is measured in children. The 95th percentile of serum total cholesterol is 210mg/d1 in male children, and 214mg/d1 in female children. And, the 95th percentile of serum triglyceride is 184mg/d1 in male children, and 191mg/d1 in female children. And, the 95th percentile of LDL-cholesterol is 133mg/d1 in male children, and 135mg/d1 in female children. Serum total cholesterol is positively .Elated to age(r=0.18), height(r=0.08), weight (r=0.17), obesity index(r=0.12), and negatively .elated to father's education level (r=-0.13), mother's education level(r=-0.13). Serum triglyceride is positively related to weight(r=0.23), age(r=0.31) and negatively .elated to father's education level(r=-0.12), mother's education level(r=-0.18). Serum HDL-C was positively reated to mother's education level(r=0.07) and negatively .elated to height(r=-0.12), weight(r=-0.09). Conclusively, the serum lipid levels of children living in Pusan is generally so high that the family and school must try to control the serum lipid levels.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.409-415
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• 2011

This study was performed to investigate the effects of Cheonggukjang added with Job's tears (CAJT) on antiobesity and lipid profiles on diet-induced obese rats. Male Sprague-Dawley rats were fed high-fat diet only (A, control), and high-fat diet with Cheonggukjang powder 10% (B), CAJT powder 10% (C), Cheonggukjang powder 20% (D), CAJT powder 20% (E) for 5 weeks. Body weight gains were similar in the experimental groups, but FER was significantly lower in the group E than group A (p<0.05), and adipose tissue weights in groups with Cheonggukjang and CAJT powder were similar to those in the group A. The lengths of small intestine were significantly longer in the groups B, C, D, and E than the group A (p<0.05). Hepatic concentrations of total cholesterol (TC) and triglyceride (TG) were similar to each other. Fecal weights were not significantly different among the groups. Fecal TC concentrations were similar in the experimental groups, but fecal TG concentrations were greatly increased in the groups B, D, and E (p<0.05). The serum TC, HDL-C and LDL-C levels varied slightly among the groups, but serum TG levels were decreased in the group D and E than in the group A (p<0.05). The AI and CRF were marginally decreased in the groups B, D, and E than in the group A (p<0.05). However, blood glucose levels were not significantly different among the groups. From the findings, it had shown that Job's tears Cheonggukjang could improve lipid profiles.