• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.123-128
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• 2004

Numerous novel ingredients have been introduced for the higher functionality of whitening cosmetics. Through the preliminary research, we have found Trichosanthes kirilowii root, Prunella vulgaris leaf and Clematis chinensis root have high whitening efficacy. But they are insoluble. Moreover the discoloration of and decrease in content take place when they are exposed to light, heat or oxygen. From Trichosanthes kirilowii root, Prunella vulgaris leaf and Clematis chinensis root, efficacious ingredients were ethanol-extracted by heating to 75∼85$^{\circ}C$ for 6∼8 h. These extracts have the inhibitory activity of tyrosinase and B16 melanin formation, thus enhancing whitening effect. We made liposomes using propylene glycol (PG)/hydrogenated lecithin/middle chain triglycerides (MCT)/glycerin/water and microfuidizer to stabilize extracts. The stability against heat and light was enhanced by 3∼5 times compared with untreated extracts. Particle size analyzer, freeze fracture transmission electron microscopy (FF-TEM), chromameter and HPLC are used for the analysis.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.341-347
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• 1998

We analyzed photoreflectance (PR) characterization of the $Al_xGa_{1-x}As$ epilayer grown by molecular beam epitaxy (MBE) method. The band-gap energy $(E_0)$ satisfying low power Franx-Keldysh (LPFK) due to GaAs buffer layer is 1.415 eV, interface electricall field $(E_i)$ is 1.05$\times$$10^4$V/cm, carrier concentration (N) is $1.3{\times}10^{15}\textrm{cm}^{-3}$. In PR spectrum intensity analysis at 300 K the $A^*$ peak below $(E_0)$ signal is low and distorted because of residual impurity in sample growth. The trap characteristic time ${\tau}_i$ of GaAs buffer layer is about 0.086 ms, and two superposed PR signal near 1.42eV consist of the third derivative signal of chemically eteched GaAs substrate and Franz-Keldysh oscillation (FKO) signal due to GaAs buffer layer.

• Fire Science and Engineering
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• v.28 no.1
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• pp.52-57
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• 2014

In this paper, the unsteady incompressible Navier-Stokes equations coupled with energy equation were solved to find out the optimal location of electrical heat trace for anti-freeze of water inside the pipe for fire protection. Since the conduction equation of pipe was coupled with the natural convection of water, the analysis of conjugate heat transfer was conducted. A commercial code (ANSYS-FLUENT) based on SIMPLE-type algorithm was used for investigating the unsteady flows and temperature distributions in water region. From the numerical experiments, the isotherms and the vector fields in water region were obtained. Furthermore, it was found that the lowest part of the pipe cross-section was an optimal position of electrical heat trace assuming the constant thermal expansion coefficient of water since the minimum temperature of the water with the position is higher than those with the other positions.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.325-331
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• 2007

A series of experiments were performed to evaluate effects of lettuce seed treatment with low temperature and dry heat treatment (DHT) on bolting response in the case of spring cultivation. During spring production in greenhouse, bolting response of the plants produced from the treated seeds was faster in the order of low temperature treatment, control and DHT. Plant height was increased 5-10 cm higher by low temperature treatment, but plant growth of some cultivars was inhibited by DHT. Difference on lettuce plant growth between low temperature treatment and DHT was gradually diminished with the lapse of time after transplanting. Fresh weight of plant was not significantly different among all treatments. 'Red Gyeolku' showed very early bolting response and plant height was significantly promoted by low temperature treatment. However, 'Cheongchima' showed low bolting percentage after various seed treatments, so it is considered late-bolting cultivar.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.65-73
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• 2006

This paper presents speed control of IPMSM drive using neural network(NN) PI controller. In general, PI controller in computer numerically controlled machine process fixed gain. They may perform well under some operating conditions, but not all. To increase the robustness of fixed gain PI controller, NNPI controller proposes a new method based neural network. NNPI controller is developed to minimize overshoot rise time and settling time following sudden parameter changes such as speed, load torque and inertia. Also, this paper is proposed speed control of IPMSM using neural network and estimation of speed using artificial neural network(ANN) controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Korean Journal of Materials Research
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• v.24 no.2
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• pp.116-122
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• 2014

$Bi_2Sr_2CaCu_2O_x$(Bi-2212) and $Bi_2Sr_2Ca_2Cu_3O_y$(Bi-2223) high-Tc superconductors(HTS) have been manufactured by plasma spraying, partial melt process(PMP) and annealing treatment(AT). A Bi-2212/2223 HTS coating layer was synthesized through the peritectic reaction between a 0212 oxide coating layer and 2001 oxide coating layer by the PMP-AT process. The 2212 HTS layer consists of whiskers grown in the diffusion direction. The Bi-2223 phase and secondary phase in the Bi-2212 layer were observed. The secondary phase was distributed uniformly over the whole layer. As annealing time goes on, the Bi-2212 phase decreases with mis-orientation and irregular shape, but the Bi-2223 phase increases because a new Bi-2223 phase is formed inside the pre-existing Bi-2212 crystals, and because of the nucleation of a Bi-2223 phase at the edge of Bi-2212 crystals by diffusion of Ca and Cu-O bilayers. In this study the spray coated layer showed superconducting transitions with an onset Tc of about both 115 K, and 50 K. There were two steps. Step 1 at 115 K is due to the diamagnetism of the Bi-2223 phase and step 2 at 50 K is due to the diamagnetism of the Bi-2212 phase.

• Korean journal of applied entomology
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• v.41 no.1
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• pp.61-65
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• 2002

This study was conducted to investigate percentage of parasitism and control effect of Liriomyza trifolii by Hemiptarsenus zilahisebessi on tomato. Percentages of parasitism on L. trifolii larva by ectopatasitoids war e 26∼45% Among them the parasitism by H. zilahisebessi was highest as 47∼75% in tomato. The parasitoids preferred 1 st to 3rd instar of host larvae. In laboratory test, the parasitoids showed high parasitism on 3rd instar larvae of host by 89.8∼93.1% when the female parasitoids were introduced by the ratios of 1 : 10, 1 : 20, and 1 : 30. In field test, 3 or 5 female parasitoids were introduced per plant. In the case, the parasitism increased to 80% 4 weeks after introduction of the parasitoids. This increased parasitism was resulted from density reduction of the host larvae There were no significant differences in parasitism, density of alive host, and percentage of damaged leaf between inoculation density.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.40-49
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• 2008

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications and so of due to their excellent power to weight ratio. To obtain maximum efficiency in these applications, this paper proposes the neural network control method. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the error back propagation algorithm(EBPA) of neural network. The minimization of loss is possible to realize eHciency optimization control for the IPMSM drive. This paper proposes high performance and robust control through a real time calculation of parameter variation such as variation of back emf constant, armature resistance and d-axis inductance about the motor operation. Proposed algorithm is applied IPMSM drive system, prove validity through analysis operating characteristics con011ed by efficiency optimization control.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.467-476
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• 2013

Freeze concentration method has advantages of high thermodynamic efficiency, low energy consumption and purified water re-use. In this study, freeze concentration waste-water system which was designed as the small and medium sized capacity was analyzed about the rate of electric power consumption and the daily treatment capacity to suggest the direction of system development. At first, power consumption and operation time of the system with fresh water precooler or without it was calculated by computer modeling and analysis. Subsequently, the change of design treatment capacity was applied to the system with fresh water cooler. As a result, the rate of electric power consumption was higher as 0.6 Wh/kg but daily treatment capacity increased in quantity as 19 % in the system with fresh water precooler. As design treatment capacity increased, the rate of electric power consumption was lower and daily treatment capacity was larger in quantity.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.243-250
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• 2020

Systematic farming can be planned and managed if long-term agricultural weather information of the plantation is available. Because the greatest risk factor for crop cultivation is the weather. In this study, a method for long-term predicting of agricultural weather using the GloSea5 and machine learning is presented for the cultivation of Chinese cabbage. The GloSea5 is a long-term weather forecast that is available up to 240 days. The deep neural networks and the spatial randomforest were considered as the method of machine learning. The longterm prediction performance of the deep neural networks was slightly better than the spatial randomforest in the sense of root mean squared error and mean absolute error. However, the spatial randomforest has the advantage of predicting temperatures with a global model, which reduces the computation time.