• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.261-265
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• 2007

A climatic feature, growth condition and incidence phase of disease and pest in Korean ginseng (Panax ginseng C. A. Meyer) were surveyed, both the conventional cultivation and culture in the forest located in Jinan. The results were as follows. The forest field was lower $1^{\circ}C$ in the air temperature, lower $1.9^{\circ}C$ in the soil temperature and 11.8% lower in the soil temperature compared with the conventional field. The wind velocity of the forest field was three times slower, but the dew condensation time was 3.3 hours longer than the conventional field. Particularly, the amounts of solar radiation in the forest was remarkably lower, while the rainfall was little lower with no significance. The incidence of disease and pest in the forest field was severe compared with that of the conventional field. Among them, Colletotrichum gloeosporioides, Cylindrocarpon destructans, and Alternaria panax was severe in the forest field while, Botrytis cinerea was severe in the conventional field. The growth condition of forest field in Panax ginseng C. A. Meyer was 50% worse in general and the root weight was 87.2% less than the 3-year-old ginseng in the conventional field.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.199-202
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• 2017

Silicon carbide (SiC) is being spotlighted as a next-generation power semiconductor material owing to the characteristic limitations of the existing silicon materials. SiC has a wider band gap, higher breakdown voltage, higher thermal conductivity, and higher saturation electron mobility than those of Si. When using this material to implement Schottky barrier diode (SBD) devices, SBD-state operation loss and switching loss can be greatly reduced as compared to that of traditional Si. However, actual SiC SBDs exhibit a lower dielectric breakdown voltage than the theoretical breakdown voltage that causes the electric field concentration, a phenomenon that occurs on the edge of the contact surface as in conventional power semiconductor devices. Therefore in order to obtain a high breakdown voltage, it is necessary to distribute the electric field concentration using the edge termination structure. In this paper, we designed an edge termination structure using a field plate structure through oxide etch angle control, and optimized the structure to obtain a high breakdown voltage. We designed the edge termination structure for a 650 V breakdown voltage using Sentaurus Workbench provided by IDEC. We conducted field plate experiments. under the following conditions: $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $75^{\circ}$. The experimental results indicated that the oxide etch angle was $45^{\circ}$ when the breakdown voltage characteristics of the SiC SBD were optimized and a breakdown voltage of 681 V was obtained.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.10a
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• pp.151-151
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• 1997

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.107-110
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• 2002

The electrophoretic deposition (EPD) technique have been applied to fabricating superconducting films and wires in former researches of our Lab. However, the particles of EPD films were usually deposited random1y on the metal substrate, the vertically combined a.c and d.c fields were applied to the EPD electrodes for orienting and densifying the particles of high $T_{c}$ superconducting deposition film on the substrate metal. Therefore, the surface states of EPD films by this combined fields could be oriented and affect to the electric properties increasing of superconducting films. The proposed method modified by a.c. assisted field to the conventional electrophoresis system was suitable to obtain improved properties with particle oriented deposition and densification.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.212-214
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• 2003

A passive loop is considered to be a cheap and easy way to be realized among the magnetic field mitigation methods. So this paper evaluates and quantizes systematically the effectiveness of a passive loop on mitigating magnetic field(M-field) and examines the feasibility and problems in adoption. To do so, first, we explain the principles of M-field mitigation through a passive loop and derive formulas for 2-D M-field analysis. Next this paper simulates the M-field mitigation patterns for a flat type 1-circuit transmission line installed a passive loop.

• Journal of the Korean Ceramic Society
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• v.34 no.12
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• pp.1254-1260
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• 1997

Influence of applied electric field on the low temperature degradation of 3 mol% YaO3 stabilized tetragonal zirconia polycrystals(3Y-TZP) was investigated using X-ray diffractometry of specimens aged under the dc field of 1.1 kV/mm in silicone oil both of 12$0^{\circ}C$-21$0^{\circ}C$. After the aging, the tetragonal to monoclinic phase transformation was observed only on the specimen surface of 3Y-TZP faced to the anode. This indicated that the surface was overcrowded with oxygen ions as a result of diffusion of oxygen vacancies toward the cathode-sided surface. To elucidate an influence of the applying time of the electric field on the extent of the degradation of 3Y-TZP in air, specimens were aged fore 0-2 hours under the electric field in the oil bath of 12$0^{\circ}C$ and then subsequently aged for 3h at 22$0^{\circ}C$ in air. The longer the specimens were aged under the field, the more extensive the transformation to the monoclinic phase was on the specimen surface faced to the cathode, probably originated from a high diffusion rate of oxygen ions due to a steep oxygen vacancy concentration gradient.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.3
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• pp.115-120
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• 2002

This Paper describes an algorithm for the design of axi-symmetrical spacer under specified field conditions. The electric field alas been calculated by combination method of Integral Equation Method(IEM) and Charge Simulation Method(CSM). The contour of spacer is represented with NURB(Non-Uniform Rational B-spline) curve of which effectiveness has been proved. This algorithm introduces a design process in the aspect of electrical field, when a spacer in airtight cylinder is designed. Also various field conditions for obtaining optical shapes have been proposed. Due to the algorithm, the entire process shows a stable convergence. Both tangential and total electrical field are taken into consideration as specified field criteria.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.1
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• pp.10-16
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• 2015

In this study, we suggest a method to predict probability distribution of a new customer's degree of loyalty using C-CRF that reflects the RFM score and similarity to the neighbors of the customer. An RFM score prediction model is introduced to construct the first feature function of C-CRF. Integrating demographical similarity, purchasing characteristic similarity and purchase history similarity, we make a unified similarity variable to configure the second feature function of C-CRF. Then parameters of each feature function are estimated and we train our C-CRF model by training data set and suggest a probabilistic distribution to estimate a new customer's degree of loyalty. An example is provided to illustrate our model.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.6
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• pp.486-492
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• 1998

The amorphous Co-based magnetic films have a large saturation flux density, a low coercive force, and a zero magnetostriction constant. Therefore, they have been studied for application to magnetic recoding heads and micro magnetic devices. However, it was found that the magnetic anisotropy was changed for each film fabrication processes. In this study, we investigated how to control the anisotropy of sputtered amorphous $Co_{89}Nb{8.5}Zr{2.5}$ films. After deposition, the rotational field annealing ant the uniaxial field annealing were performed under the magnetic field of 1.5 kOe. the annealing was done at the temperature range from 400 to $600^{\circ}C$ for one hour. As-deposited amorphous $Co_{89}Nb{8.5}Zr{2.5}$ thin film had saturation magnetization ($4\piM_5$) of 0.8 T, coercive force($_IH_C$) of 1.5 Oe, and anisotropy field($H_k$) of 11 Oe. The amorphous $Co_{89}Nb{8.5}Zr{2.5}$ thin films annealed by rotational field annealing at $500^{\circ}C$ for one hour was found to be isotropy, and $4\piM_5$ of 0.9 T was obtained from these films, Also, the magnetic anisotropy of as-deposited films could be controlled by uniaxial field annealing at $400^{\circ}C$ for one hour. Anisotropy field($H_k$) of 17 Oe and $4\piM_5$ of 1.0 T were obtained by this method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.157-162
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• 2003

For fabricating high T$\sub$c/ superconducting deposition film, novel electrophoretic deposition (EPD) technique applied to deposit surface charged particles on metal substrate with only d.c field has been studied. However, the electric properties of superconducting film could not be improved easily by this way, because the particles of EPD film were usually deposited randomly on metal substrate without any directional orientation affected to its critical current density. For the purpose of obtaining partcle orientation on the EPD films, the new method modified by a.c. assisted field to the conventional electrophoresis system was investigated to improve the particle deposition density and to increase the contacting area among the particles with highly oriented particle deposition of BSCCO superconducting film.