• Natural Product Sciences
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• 제1권1호
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• pp.5-9
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• 1995

The metabolites of marine mollusk Mytilus edulis were isolated and characterized, revealing the presence of the rare free fatty acids and proteinogenic amino acids together with a non-proteinogenic free amino acid, taurine. The free fatty acids in this organism were particularly interesting for the presence of both unusual n-6 acid [20:4 (n-6)] and triple bond containing acid (2,5-octadecadiynoic acid). In addition to the proteinogenic amino acids commonly found in proteins, non-proteinogenic free amino acid taurine was isolated and the structure was determined by its physicochemical properties. Recently taurine has been given much interest in the molecular level because of diverse biological activities and the medicinal properties. Furthermore, the result of the analyses of analyses of free amino acids showed that glycine, glutamic acid, serine and alanine, which were considered to be related to the taste of this organism, are predominantly present.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.717-722
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• 2003

To improve the shock resistance of the microdrive under non-operating conditions, an isolator was attached to the contacting part of the microdrive. Through FE analysis, design parameters for satisfying the allowable acceleration level of the spindle motor bearing part were presented, which is a most possible critical part of the microdrive.

• Archives of Pharmacal Research
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• 제26권11호
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• pp.902-905
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• 2003

Five compounds of terpenoids and coumarins were isolated from the non-polar fraction of Artemisia apiacea by open column chromatography. Their structures were elucidated as $\alpha$-amyrin (1), $\beta$-amyrin (2), $\beta$-sitosterol (3), 5,6,7-trimethoxycoumarin (4) and 6-methoxy-7,8-methylenedioxycoumarin (5) by chemical and spectroscopic analysis. This is the first report of the isolation of $\alpha$-amyrin, $\beta$-amyrin, 5,6,7-trimethoxycoumarin and 6-methoxy-7,8-methylene-dioxycoumarin from this plant.

• 소음진동
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• 제9권3호
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• pp.472-476
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• 1999

The effect of static preload on the dynamic properties of rubber materials is rather important, especially when good isolation characteristics are required at high frequencies. However, there are still few papers for dynamic characteristics of compressed rubber components. It was demonstrated in reference (4) that for bonded rubber material of a cylindrical shape, a simplified theory equation between linear dynamic and nonlinear static behavior of rubber material was useful to predict their combined effects. This paper presents the second part of the study. It is confirmed that for the compressed rubber material, the stress can be factored into a function of frequency and a function of strain(stretch). The finite element methodis applied to analyze non-linear large deformation of rubber material and its results are compared with those of a simplified theory equation. The predicted dynamic material properties based on non-linear static finite element analyses have a good agreement of experimental results and those based on simplified theory equation.

• 생약학회지
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• 제48권4호
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• pp.280-284
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• 2017

Lion's Mane Mushroom, Hericium erinaceum, is a traditional edible mushroom widely used in culinary applications. It has been also used as a medicine in East Asian countries due to its various biological activities. Chemical investigation of fruiting bodies of this mushroom afforded many aromatic compounds, which were mostly isolated from polar fraction of its extracts. Herein we tried to investigate non-polar compounds from the extracts of this mushroom. $CHCl_3$-soluble fraction of the extracts was subjected to chemical investigation, which resulted in isolation of four compounds. Their chemical structures were elucidated as ircicerebroside (1), cortenuamide A (2), 1-D-arabinitol-monolinoleate (3), and cinnamic acid (4) on the basis of spectroscopic data. To the best of our knowledge, this is the first report of compounds 1, 2, and 4 from Hericium erinaceum.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.340-346
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• 1994

Six bacterial strains capable to grow on medium containing cholesterol as sole carbon source were isolated from soil, pork fat and cheese. Three of them were tentatively identified as Rhodococcus species, Rhodococcus sp. CD-1, R. sp. CD-2, and R. sp. CD-3. All the isolates showed a varying amount of cholest-4-en-3-one as the degradation product, and three strains of Rhodococcus spp. showed rapid degradation of cholesterol. Radioisotopic studies revealed that cholesterol was degraded to non-sterol hydrophilic compounds via cholest-4-en-3-one, and presumably to C0$_{2}$- These strains showed two distinct patterns in further degradation of cholest-4-en-3-one. By one group, R. sp. CD-1 and R. sp. CD-3, cholest-4-en-3-one was rapidly converted to non-sterol inter- mediates without significant accumulation of sterol derivatives in the culture broth. In contrast, by another group, R. sp. CD-2, the substantial amount of cholest-4-en-3-one was accumulated indica- ting a lower conversion of the compound to the next metabolites.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권11호
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• pp.663-669
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• 1999

This paper presents new self excited DC-DC converters such as Buck-boost type, Buck type and also non-inverting Buck-boost type. The proposed converters has the following advantages: simple topology, small number of circuit components, easy control method. Therefore, these converters are suitable for the portable appliances with battery source. It is especially suited for low power DC-DC conversion applications where non isolation output power is usually required. The steady state characteristics of proposed self exciting Buck-boost DC-DC converter are analysis and the result shows good agreement with experimental value. Furthermore the experimental results for 50W class self oscillating Buck-boost DC-DC converter have been obtained, which demonstrate the high efficiency and good performance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1468-1476
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• 2006

The goal of this thesis is to support safety and reliability characteristics of software intensive critical systems. The verification method developed is innovative from current state of the art in what concerns the verification viewpoint adopted: focusing on software faults, and not, like many other approaches purely on fulfilling functional requirements. As a first step and based on a number of well defined criteria a comparison was made of available literature in the area of static non formal non probabilistic software fault removal techniques. But, None of the techniques evaluated fulfilled all criteria set in isolation. Therefore a new technique was developed based on a combination of two existing techniques: the FMEA and FTA. These two techniques complement each other very well. It is possible to integrate both techniques with commonly used techniques at system level. The resulting new technique can be shown to combine nearly all aspects of existing fault removal techniques.

• Journal of Power Electronics
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• 제15권4호
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• pp.920-928
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• 2015

Transformerless solar inverters have a higher efficiency than those with an isolation link. However, they suffer from a leakage current issue. This paper proposes a family of single phase six-switch transformerless inverter topologies with an ac bypass circuit to solve the leakage current problem. These circuits embed two unidirectional freewheeling current units into the midpoint of a full bridge inverter, to obtain a freewheeling current path, which separates the solar panel from the grid in the freewheeling state. The freewheeling current path contains significantly fewer devices and poor performance body diodes are not involved, leading to a higher efficiency. Meanwhile, it is not necessary to add a voltage balancing control method when compared with the half bridge inverter. Simulation and experiments are provided to validate the proposed topologies.

• Journal of Digestive Cancer Research
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• 제4권2호
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• pp.77-82
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• 2016

The 26^th World Congress of the International Association of Surgeons, Gastroenterologists and Oncologists (IASGO) was held in Seoul, Korea from September 8 to 10, 2016. In this congress, I gave a State-of-the-Art Lecture II entitled "Mesenteric Approach in Pancreatoduodenectomy." The ideal surgery for pancreatic head cancer is isolated pancreatoduodenectomy, which involves en bloc resection using a non-touch isolation technique. My team has been developing isolated pancreatoduodenectomy for pancreatic cancer since 1981, when we developed an antithrombogenic bypass catheter for the portal vein. In this operation, the first and most important step is the use of a mesenteric approach instead of Kocher's maneuver. The mesenteric approach allows dissection from the non-cancer infiltrating side and determination of cancer-free margins and resectability, followed by systematic lymphadenectomy around the superior mesenteric artery. This approach enables early ligation of the inferior pancreatoduodenal artery and total mesopancreas excision. It is the ideal surgery for pancreatic head cancer from both oncological and surgical viewpoints. The precise surgical techniques of the mesenteric approach are herein described.