• Journal of Energy Engineering
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• v.22 no.2
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• pp.169-174
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• 2013

An experimental study has been conducted for the design of the regenerative oxy-fuel combustion system with ceramic ball. Various design parameters are considered such as ball size, regenerator weight, and combustion load. Regenerative system with a pair of oxygen burners and regenerators is set up and the temperature of oxygen and exhaust gas passing through ball regenerator is measured. It is shown that the temperature distributions with time are affected by ball diameter and regenerator weight, and the significant temperature change is observed by combustion load. As the ball size decreases and the regenerator weight increases, the regenerating temperature efficiency increases. It is found that the heat recovery ratio is low despites of high regeneration temperature efficiency.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.164-170
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• 2007

In this paper, the development results of electromechanical TVC actuation system is described in the aspect of design, analysis, manufacturing and test. The kinds of prime power for TVC actuation system is classified by the variety of propulsion system of launch vehicle. The electric power by battery is the sole candidate for prime power of TVC actuation system at the view point of feasible domestic infra technologies for the present. The characteristic analysis study is performed between electromechanical and electrohydraulic actuation system with respect to power efficiency, performance and weight efficiency. The electromechanical actuation system has superiority of power and weight efficiency according to less opportunity of power conversion process.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.177-187
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• 2002

In this paper, we consider a multi-factor, multi-cause decision making problem of supply chain. And we show how to measure the operational efficiency of the components in supply chain and also how to improve the efficiency of each component and whole supply chain. As a methodology, the data envelopment analysis (DEA) is adopted to measure the efficiency by considering weight factors such as flexibility, information sharing, logistics level, etc. The proposed algorithm allows whole supply chain to have the improved efficiency rate.

• KSBB Journal
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• v.13 no.5
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• pp.518-523
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• 1998

A large quantity of ethylene glycol(EG) is remained in the effluent after pretreating polyester weight-loss wastewater physicochemically in the fist stage and must be treated biologically in the second stage. Therefore, an excellent EG-utilizing bacteria strain was isolated from the natural system and the optimal culture conditions of the strain were investigated. The optimal culture conditions of temperature, pH, and nitrogen source were found to be 35$^{\circ}C$, 7.5 and ammonium chloride, respectively, when CODCr removal efficiency was more than 90%. The growth of stains and EG removal efficiency was slightly improved by adding elements such as niacin and biotin. With increasing inoculation size in a batch culture, the removal efficiency of EG was conspicuously increased. Growth rate was inhibited when the initial concentration of EG was more then 30g/L. The strain was identified as Pseudomonas sp. based on morphological and biological characteristics and named as Pseudomonas sp. EG1.

• Journal of environmental and Sanitary engineering
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• v.19 no.1
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• pp.37-41
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• 2004

The removal efficiency of cadmium by chitosan complex isolated from Aspersillus oryzae was investigated through laboratory experiments. The results of the study are as follows. The adsorption kinetics of cadmium was reached the adsorption equilibrium in approximately 20 minutes and the removal efficiency was showed 95.8%. The effect of temperature on cadmium adsorption by chitosan complex shows that as the temperature increased, the amount of cadmium adsorption per unit weight of chitosan complex increased. The correlation between amount of cadmium adsorption per unit weight of chitosan complex and temperature was obtained through the coefficient of determination($R^2$). $R^2$ values was 0.854(p<0.05). A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constant, the adsorption intensity(1/n) was 0.550, and the measure of adsorption(k) was 2.181. So, it was concluded that adsorption of cadmium by chitosan complex is effective.

• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.401-405
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• 2012

Corrosion inhibition efficiencies of holy basil on Al in HCl solution were studied by weight loss and thermometric methods in presence and in absence of stem extract of three different varieties of holy basil viz. ocimum basilicum ($E_B$), ocimum canum ($E_C$) and ocimum sanctum ($E_S$). Inhibition efficiency increases with the increasing concentration of stem extract and decreases with increases in acid strength. Results show that all varieties under study are good corrosion inhibitors, among which, $E_B$ is most effective. Maximum inhibition efficiency was found 97.09% in 0.5N HCl solution with 0.6% stem extract. The Langmuir adsorption isotherm indicates that surface coverage also increases with increasing in the concentration of extract of stem in HCl solution.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_3
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• pp.1223-1231
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• 2023

In the case of internal combustion engine vehicles, transmissions are essential for various reasons, such as vehicle starting and speed control. However, in the case of electric vehicles, unlike internal combustion engine vehicles, a transmission is not necessarily required. Of course, considering the efficiency of electric vehicles, a transmission is necessary, but installing the existing transmission as is has the opposite effect due to increased vehicle weight, so it has not been considered so far. In this paper, a non-contact reducer type using the Arago disc effect is proposed rather than a transmission using a conventional gear train, and the aim is to examine whether this can increase the driving efficiency of electric vehicles while minimizing weight. In addition, the effectiveness of the proposed reducer will be verified by manufacturing and testing it.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.2
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• pp.82-89
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• 1985

A new non-inferior solution is obtained by investigating method of weight p- norm to explain the conception of MCO (multiple criterion optimization) problem. And then the optimum non-inferior solution is obtained by the weight minimization method applied to objective function of MOSFET NAND rATEAlso this weight minimization method using weight P- norm methods can be applied to non-convex objective function. The result of this minimization method shows the efficiency in comparison with that of Lightner.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.486-491
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• 2002

Spikelet number and its components of rice plant are closely associated with nitrogen accumulation and biomass production during panicle formation stage. To elucidate this relationship and also compare the differences of the sink formation efficiency among cultivars, spikelet number, its components, nitrogen content, nonstructural carbohydrate content, and plant dry matter were investigated under 5 nitrogen levels with two split application methods and shading treatments by using three rice varieties. The nitrogen amount in shoot at panicle initiation stage and at 15 days after panicle initiation showed significant positive correlation with primary rachis branches per square meter, and that at 15 days after panicle initiation and at heading stage with secondary rachis branches per square meter, Primary and secondary rachis branches per square meter showed positive significant correlation with the shoot dry weight at panicle initiation stage and at 15 days after panicle initiation stage, respectively, The amount of degenerated secondary rachis branches and spikelets per square meter showed significant negative correlation with the dry weight and nonstructural carbohydrate increase of stem during 15days after panicle initiation, and the contents of nonstructural carbohydrate at 15 days after panicle initiation. Spikelets per unit area showed significant positive correlation with nitrogen amount in shoot and shoot dry weight at heading stage. The sink formation efficiency expressed as the spikelet number produced by the unit amount of nitrogen in shoot at heading stage was higher in Nampoongbyeo than Choocheongbyeo and Hwaseongbyeo. Sink formation efficiency was negatively correlated with the dry weight increase of shoot and stem during reproductive stage. but not significantly with that of leaf in all varieties. Sink formation efficiency was not significantly correlated with nonstructural carbohydrate, but was significantly negatively correlated with structural carbohydrate increase during reproductive stage.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.49-54
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• 2003

This study was carried out to investigate the effects of the inoculated diet with Paecilomyces japonica on weight gain, feed efficiency and cordycepin contents in the breast and thigh meats of broilers. One hundred and twenty broiler chicks were divided into four dietary groups ; 1) control (basal diet), 2) T1 (substituted with 5% inoculated diet), 3) T2 (substituted with 10% inoculated diet) 4) T3 (substituted with 20% inoculated diet) during 4 weeks. Cordycepin contents of inoculated diet with Pacilomyces japonica was significantly higher than before inoculation (P<0.05). Body weight gain and feed efficiency were highest in T1 group when fed starter diet (P<0.05) but these were lowest in T3 group fed when fed finished diet (P<0.05). Body weight gain and feed efficiency were the lowest in T2 group for overall period than other groups. Cordycepin contents of breast and thigh meats were significantly higher in Pacilomyces japonica groups than control at 5 weeks of age (P<0.05). However, it was similar among the T1, T2 and T3 groups. These results indicated that body weight gain and feed efficiency tended to increase in birds fed replaced 5% inoculation diet Cordycepin contents of breast and thigh meats would be increased significantly in birds fed inoculated diet (P<0.05).