• Food Science and Biotechnology
• /
• 제14권3호
• /
• pp.392-398
• /
• 2005

Fresh, and sun- and oven-dried red peppers were analyzed for volatile components. Also, their odor-active compounds were determined using gas chromatography-olfactometry (GC-O). More diverse volatile components, such as aldehydes, ketones, acids, and esters, were found in dried samples than in fresh ones. They included hexanal, ethyl acetate, ${\alpha}$-ionone, and ${\beta}$-ionone. Some Strecker aldehydes, 2-methyl butanal and 3-methyl butanal, were found only in dried red peppers. More hydrocarbons of high volatility and terpene-type components, such as ${\gamma}$-terpinene and aromadendrene, were detected only in fresh red peppers. A considerable amount of naphthalene was formed during sun-drying, whereas 2-furancarboxaldehyde, 1-methyl-1H-pyrrole and benzeneethanol were detected only in oven-dried red peppers. Characteristic odor of fresh ones could be attributed to 3-penten-2-o1, 2-methyl-2-butenal, 2-methoxy phenol, 2-hydroxy-methyl-benzoate, and 2-phenoxy ethanol, whereas some odorants, including 2-pentyl furan, naphthalene, hexyl hexanoate, and ${\alpha}$-ionone, could be responsible for distinctive odor property of sun-dried red peppers. 2-Furancarboxaldehyde, benzeneethanol, 4-vinyl-2-methoxy phenol, and unknown played important roles in odor property of oven-dried red peppers.

• 한국연초학회지
• /
• 제19권2호
• /
• pp.124-128
• /
• 1997

Semivolatile components in mainstream smoke of cigarette attached the different type filter were analysed. Based on the main peak of GC profile, benzene, toluene, acetic acid, limonene, acetamide, pyridine, nicotine, phenol, pyrrole, and furfuryl alcohol were identified. The amount delivered of semivolatile components by each filter was evaluated with the ratio of areas of sample vs area% of ISTD. By comparing dual and triple filter to mono filter, the delivery amounts were 52% benzene, 62% toluene and 74% benzene, 84% toluene, respectively. The delivery amount of limonene which was known of tobacco taste component, were 52%, and 93% by dual and triple filter, respectively. Also, delivery amounts of acetic acid which was one of acidic compounds in smoke, were 86% and 83% by dual and triple filter, respectively. When adding the same amount of active carbon, the amounts delivered of vapour phase such as benzene and toluene by dual filter were lower than that of triple filter. But the delivery amounts of acetic acid and phenol by dual filter were higher than that of triple filter. This results assume that the pH of active carbon in filter affect to the adsorption or absorption of triacetin during filter making process.

• Biomolecules & Therapeutics
• /
• 제2권2호
• /
• pp.149-154
• /
• 1994

Anti-allergic and anti-inflammatory actions of the water extract from Cimicifuga heracleifolia were evaluated in mice and rats. Several criteria were employed to assess the anti-allergic and anti-inflammatory actions of Cimicifuga heracleifolia, such as hyaluronidase activity, mediators-induced vascular permeability changes, 48 hour homologous passive cutaneous anaphylaxis (PCA) histamine release from mast cells, and the carrageenan-induced rat paw edema. To further characterize the active components, the water extract was either extracted with organic solvent or fractionated according to molecular weight, and each fraction was tested for some of anti-allergic parameters. Hyaluronidase activities, both in activating and in activated states, were significantly inhibited by the water extract of Cimicifuga heracleifolia and by some of its subfractions, molecular weight less than 1,000. The water extracts (50~400 mg/kg) significantly inhibited 48 hr homologous PCA and vascular permeability changes induced by chemical mediators (histamine, serotonin, and leukotriene $C_4$) in mice. In the case of histamine-induced vascular permeability changes, more extensive studies were conducted; water extract was either fractionated according to molecular weight or extracted with butanol. Anti-histamine actions were observed only from the water layer, and these active components were of the molecular weight less than 1,000. These anti-allergic actions were observed mainly from mice than from rats. On the other hand, anti-inflammatory actions of the water extract from Cimicifuga heracleifolia were significant in rats.

• 전력전자학회논문지
• /
• 제27권5호
• /
• pp.391-396
• /
• 2022

In this study, a new voltage-balancing dual-active bridge converter that integrates a DAB converter with a voltage balancer is proposed for a bipolar DC distribution system. The proposed converter is configured to connect two loads to the transformer secondary center tap of the DAB converter, and no additional components are added. The proposed converter has the same operation as the conventional DAB converter, and it makes both output voltages similar. Moreover, the imbalanced current offset between the two loads is bypassed only on the secondary side of the transformer. Consequently, the proposed converter integrates a voltage balancer without any additional components, and no additional loss occurs in the corresponding components. Thus, high efficiency and high power density can be achieved. The feasibility of the proposed converter is verified using 3 kW prototypes under 380 V input and 190/190 V output conditions.

• 대한본초학회지
• /
• 제28권3호
• /
• pp.39-44
• /
• 2013

Objectives : The purpose of this study was to identify active fraction and components from antiplatelet Ulmi cortex extract. Methods : The 70% ethanol extract of Ulmi cortex was subjected to column chromatography over D101 resin and eluted with an 20% (W1), 30% (W2), 40% (W3), 50%(W4), 70% (W5), and 100% ethanol (W6) to yield 6 fractions. W6 was further fractioned and its active components were purified using semi-preparative HPLC. The isolated compounds were identified by MS and NMR, and their contents were simultaneously analyzed using HPLC/UV. Antiplatelet aggregation activities of the fractions and the compounds were evaluated using rat platelet-rich plasma in presence of collagen ($5{\mu}g/ml$), arachidonic acid (0.05 U/ml), or thrombin ($100{\mu}M$). Results : Among six fractions, W3 prominently inhibited platelet aggregation. At the concentration of $200{\mu}g/ml$, W3 strongly inhibited arachidonic acid- and collagen-induced platelet aggregations by 78.2% and 65.9%, respectivley, and weakly inhibited thrombin-inducded platelet aggregation by 32.6%. Catechin, epicatehin, and catechin-7-O-${\beta}$-D-glucopyranoside were isolated from W3 and their contents were revealed to be 15.1%, 0.87%, and 0.32%. Catechin and epicatechin at the concentrations of $100{\mu}M$ strongly inhibited collagen-induced platelet aggregation by 79.9% and 86.6%, respectively, but weakly inhibited arachidonic acid- and thrombin-induced platelet aggregations. Conclusions : A main active principle of anitplatelet Ulmi Cortex extract is W3 fraction, of which main active component is catechin considering its antiplatelet activity and content.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
• /
• pp.141-145
• /
• 2006

The possibility of an active-matrix carbon nanotube field emission display (AM-CNT FED) is discussed from the view points of display performance and cost. The critical issues for FED commercialization such as anode acceleration voltage, uniformity, stability and reliability can be solved through our AM-CNT FED technologies.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.907-911
• /
• 2000

In this study, a modified model for prediction of cutting force components in down end milling process is presented. Using this cutting force components of 4-tooth endmills with various helix angles have been predicted. Predicted values of cutting force components are well coincide with the measured ones. As helix angle increases overlapping effects of the active cutting edges increase and as a result the amplitudes of cutting force components decrease.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
• /
• pp.3-7
• /
• 2000

In this study, a modified model for prediction of cutting force components in up end milling process is presented. Using this cutting force components of 4-tooth endmils with various helix angles have been predicted. Predicted value of cutting force components are well coincide with the measured ones. As helix angle increases overlapping effects of the active cutting edges increase and as a result the amplitudes of cutting force components decrease and the specific cutting energy consumed also decreases

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제53권5호
• /
• pp.351-357
• /
• 2004

In this paper, we present an analytical method that provides fast and efficient evaluation of the conversion efficiency for switching power supplies. In the proposed method, the conduction losses are evaluated by calculating the effective values of the ideal current waveform first and incorporating them into an exact equivalent circuit model of the switching power supply that includes all the parasitic resistances of the circuit components. While the winding losses and core losses are accurately accounted for the magnetic components, the skin and proximity effects are assumed to be negligible in order to simplify the analysis. The validity and accuracy of the proposed method are verified with experiments on a prototype active-clamped forward converter with synchronous rectification. An excellent correlation between the experiments and theories are obtained for the input voltages of 36-75 V with 4-6 MOSFETs employed for the synchronous rectification.

• Journal of Dairy Science and Biotechnology
• /
• 제31권2호
• /
• pp.195-200
• /
• 2013

The ripening of cheese allows for the development of characteristic taste and flavour, nutritional substances, bio-active components and texture, helping to improve quality. Many different microbiological, biochemical and nutritional changes occur during the process depending on the quality of raw milk, added cultures and enzymes, as well as specific processing and ripening conditions. During the ripening lactose is hydrolyzed to lactic, propionic and acetic acid, helping to reduce potential effects of the problem of lactose intolerance. Fat is hydrolyzed to butyric, propionic and conjugated linoleic acid, which function as bio-active substances. Protein is hydrolyzed to different peptides and amino acids which all show various bio-activities. However, errors of cheese ripening can happen and affect the quality of the product. To guarantee good quality cheese the process needs to be managed carefully with the right microbes used and ensuring cleanliness of processing facilities, staff, ventilation and hazard analysis and critical control points (HACCP). Research into and controlling of ripening technology is crucial for producing high quality cheeses.