• Journal of Korea Foundry Society
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• v.20 no.2
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• pp.97-103
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• 2000

In this study, a design of experiment, Taguchi method, was applied to optimize gating system design of escalator step die casting parts. Six shape factors which affect filling sequence of melt are adopted and divided into two levels respectively. Initial feeding differences of melt which were calculated by using S/N(signal-to-noise) ratio in each condition were demonstrated with the simulation of Flow-3D software program. Variations of S/N ratio according to shape factors were obtained and the optimal condition of gating system could also be obtained. It could be found that width of gate, contact angle of gate, thickness of runner are more effective factors on the filling sequence of melt than the others in this case of escalator step die casting parts. It showed that the economical gating system and sound filling sequence of melt were obtained by using Taguchi method.

• Journal of Nutrition and Health
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• v.36 no.8
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• pp.801-810
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• 2003

Chronic alcoholism is considered a common cause of malnutrition. Especially, micronutrient deficiency may playa critical role in the incidence of alcoholic liver diseases. This study was conducted to investigate the effect of folate deficiency and ethanol consumption on cholesterol metabolism and the antioxidative system in rats. Plasma concentration of total cholesterol was increased by ethanol administration in folate-fed rats. HDL-cholesterol tended to be higher in the folate-fed group, but it was not significant. The plasma and hepatic levels of malondialdehyde were increased after chronic ethanol feeding, but dietary folate depressed the plasma malondialdehyde content of rats. Ethanol or folate feeding did not significantly change alcohol dehydrogenase activity. But folate feeding increased catalase activity in ethanol-fed rats. There was no significant change in superoxide dismutase activity among the experimental groups. Glutathione peroxidase activity tended to decrease by chronic ethanol feeding, but dietary folate did not affectthe glutathione peroxidase activity of chronic ethanol-fed rats. Glutathionine-S-transferase activity was not affected by ethanol feeding or folate deficiency. The plasma and hepatic levels of retinol decreased after chronic ethanol feeding. The hepatic level of retinol significantly decreased in ethanol-fed rats by folate deficiency. The plasma level of $\alpha$-tocopherol tended to be low in the folate deficient group with ethanol feeding, but there was no difference among the experimental groups in the hepatic level of $\alpha$-tocopherol. These results demonstrate that chronic ethanol consumption changes the plasma cholesterol metabolism and antioxidative system of rats, and optimal folate feeding in ethanol-fed rats exerts protective effects to some extent.

• Journal of Life Science
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• v.20 no.6
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• pp.811-818
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• 2010

Optimal agitation speed and aeration rate for the production of gellan by Sphingomnas paucibilis NK2000 in a 7 l bioreactor were found to be 400 rpm and 1.0 vvm. The best time for glucose feeding into the medium for enhanced production of gellan by S. paucibilis NK2000 was 36 hr after cultivation. The concentrations of gellan produced by S. paucibilis NK2000 from 1) 20.0 g/l glucose without additional feeding, 2) 20.0 g/l glucose with feeding of 200.0 g/l glucose at 36 hr, in which the final concentration in the medium was 10.0 g/l, 3) 20 g/l glucose with feeding of 200.0 g/l glucose and a shift in an agitation speed from 400 to 600 rpm, 4) 20.0 g/l glucose with feeding of 200.0 g/l glucose at 36 hr and shifts in an agitation speed from 400 to 600 rpm and an aeration rate from 1.0 to 1.5 vvm, 5) and 20.0 g/l glucose with feeding of 200.0 g/l glucose at 36 hr and shifts in an agitation speed from 400 to 600 rpm and an aeration rate from 1.0 to 2.0 vvm, were 5.19, 5.74, 6.73, 7.93, and 9.40 g/l, respectively, and their conversion rates from glucose were 26.0, 19.1, 22.4, 26.4, and 31.3%, respectively. Compared to those developed using a normal process, production of gellan by S. paucibilis NK2000 from 20.0 g/l glucose was 1.81 times higher, and and its conversion rate was 1.20 times higher when the optimized process developed in this study was used.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.908-913
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• 1999

This experiment was conducted in three trials to evaluate optimal ambient temperature for a novel milk replacer feeding system designed for early-weaned pigs, compared to commercial dry diets fed within a conventional hot nursery. A total of 165 PIC genotype pigs were weaned at $13.89{\pm}0.7$ days of age and allotted to one of two dietary treatments in three trials based on weight and litter origin. Each trial consisted of pigs fed dry diets (DD) and pigs fed milk replacer (MR) which was offered in one of 3 different ambient temperatures. Pigs fed milk replacer were housed in a specialized nursery building in which one half of each pen contained an enclosed hover that was thermostatically maintained at $32^{\circ}C$ while the exterior ambient temperature (where milk was fed) was set at either 17 (trial 1), 24 (trial 2) or $32^{\circ}C$ (trial 3). Pigs fed dry diets with the conventional nursery were maintained at $30^{\circ}C$ for each trial. From d 21 to d 49, all pigs were fed DD within a standardized hot nursery environment. During the first week (d 14-21), pigs fed MR showed increased ADG from 214% to 228% over control pigs fed DD (p<0.001), regardless of ambient temperature. As ambient temperature was increased from 17 to 24 to $32^{\circ}C$, ADG of MR-fed pigs was increased by 214%, 220% and 228% over those of pigs fed DD, respectively. ADFIs of MR-fed pigs at $17^{\circ}C$, $24^{\circ}C$, and $32^{\circ}C$ compared with pigs fed DD were increased by 108%, 139% and 164% from d 14 to d 21, respectively. Fed efficiency (G/F) of MR-fed pigs at $17^{\circ}C$, $24^{\circ}C$, and $32^{\circ}C$ compared with pigs fed DD were 199%, 162% and 139% of those of pigs fed DD, respectively. As ambient temperature increased, diarrhea scores showed a slight tendency to increase. The advantage of MR feeding was greater when the ambient temperature was higher, but G/F was impaired with increased ambient temperature. We conclude that ambient temperature within the specialized nursery influenced behavior, MR feed intake, and probably piglet energy expenditure. There were no differences between MR-fed and DD-fed pigs for ADG, ADFI and G/F in the subsequent growth period (d 21 to d 49, p>0.05). Maximal advantage of MR feeding was obtained at the intermediate ($24^{\circ}C$) ambient temperature during the overall period (p<0.05). Results from this experiment indicate that a milk replacer feeding system utilized in the early postweaning period can maximize pig growth performance, and that ADG, ADFI and G/F were affected by different ambient temperatures within MR-fed pigs. The high or low temperatures could not support the maximal growth of pigs fed MR.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.515-525
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• 1998

In this paper, for both transmission and reception with single antenna system of satellite communication, dual-frequency antennas which operate simultaneously at 12.5 GHz and at 14.25 GHz are designed, constructed and measured. Also by using dual feeding structure, the problems of single-fed dual-frequency antenna such as the separation of transmitting and receiving signals and single polarization, are solved. Microstrip patch as a radiation element of dual-fed dual-frequency antenna has width and length which are the resonance lengths of the corresponding frequencies for transmission and reception, respectively. The effects of the feed line on the other frequency feeding are minimized with the optimal matching scheme for the feed lines. For solving the space problems of dual-fed two-dimensional array antennas, microstrip-line and coaxial probe feedings are used for each frequency and a two-dimensional $2\times2$ array antenna was designed and measured their characteristics. The experimental results show that errors of resonance frequencies are less than 1.44%, the return losses are less than -21 dB and the isolations between two feeding ports are less than -21 dB. The characteristics of radiation patterns of dual frequency microstrip antenna are measured and evaluated. The directivities, sidelobe levels and cross polarizations are also measured and compared with the simulations. The results show some errors due to the misalignment of coaxial probe feeding.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.273-279
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• 1990

For poly- $\beta$ -hydroxybutyrate (PHB) production, a pink-pigmented facultative methylotrophic bacterium (PPFM) P-10 was newly isolated from soils through methanol-enrichment culture. The optimal medium composition for cell growth was 1.0% (vlv) of methanol as carbon source and l.Og/l of ,TEX>$NH_4Cl$, equivalent to C/N ratio of 13.2 at pH 7.0 and $30^{\circ}C$. To investigate the optimal condition for YHB accumulation, two-stage culture technique was adopted; first stage for cell growth and second stage for accumulation of PHB providing unbalanced growth conditions. The optimal PHB accumulation was 1.0% (vIv) of methanol and 0.26gll of $NH_4Cl$, C/N of 50.8 at pH 6.0. To overcome methanol inhibition on cell growth, intermittent feeding fed-batch culture technique was employed, and the cell concentration as high as 14gll with 40% of PHB was achieved. The purified PHB was identified using IR and $1^H NMR$ as homopolymer of 8hydroxybutyric acid. The absorption spectrum of extracted pink colored microbial pigment was alsa investigated.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.15 no.2
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• pp.79-84
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• 2012

Pediatric patients in hospital are at risk of malnutrition at admission and even during their hospitalization. Although the concept of nutritional support team (NST) was introduced to hospitals for optimal nutritional care since 1960s and the benefits of pediatric NST have been proven by many studies and reports in terms of patient clinical outcome and cost saving, the pediatric NST is not widespread yet. The pediatric NST composed of pediatricians, dieticians, pharmacist, and nutrition support nurses as core members dedicated to nutritional care in children should be independent of central NST or other disciplines, but closely cooperate with other teams in hospitals. There is no doubt that a multidisciplinary NST is an effective way to provide appropriate nutritional support to an individual patient. Therefore, the implementation of the pediatric NST in hospitals should be recommended to provide optimum nutritional support including enteral tube feeding and parenteral nutrition and to assess pediatric patients at risk of malnutrition.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.241-244
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• 2003

The productivity of hydroforming process can be increased by combining pre-forming process and post-forming process such as the bending, piercing and the embedding process. Therefore in this study, integrated studies on the hydro-embedding technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters. In the case of the embedding test the characteristics of the embedded parts, such as the shape of the screw tip, screw thread and shape of thread were investigated at various process conditions. To measure the clamping force between the embedded part and the tube, special measuring device was used.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.145-147
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• 1996

Traction Motor is being transferred to the squirrel cage induction motor from D.C motor, by the improved power semiconductors like GTO, IGBT, etc. In the Induction Motor, inverter system must be used for delivering variable voltage variable frequency. But, by pulsating in the system the harmonics would be produced, and that cause the torque ripple and enfeeble the dynamic characteristics of the motor. So, to use the inverter system, we should take the torque ripple into consideration. To minimize the torque ripple in the VSI fed Traction Motor, the optimal pulsating was presented in this paper. By using the SPWM(Sinusoidal Pulse Width Modulation) method, feeding the appropriate pulse, we can minimize the torque ripple and improve the transient response.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.81-84
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• 2001

A real time optimization algorithm for fed-batch cultures of recombinant yeast to determine the optimal substrate feed rate profile has been developed. Its development involved four key steps: (1) development of reliable adaptive model. (2) development of optimization algorithm. (3) design of on-line model update algorithm to be incorporated into the optimization algorithm and (4) experimental validation. A recombinant Saccharomyces cerevisiae producing human parathyroid hormone (hPTH) was chosen as the model strain. It was found to be very successful in maintaining cell growth and galactose consumption at leigh levels, thus resulting in significant improvements in the productivity (up to 2.1 times) and intact hPTH concentration (up to 1.5 times) compared with the case of an intermittent glucose and galactose, or galactose feeding.