• 제목/요약/키워드: a.c field

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인삼 임간재배시 병해충 발생율 및 생육 특성 (Growth Characteristics and Occurrence Rate of Disease and Pest According to the Forest Field in Panax ginseng C. A. Meyer)

  • 정성수;박종숙;양재춘;류정;김희준;임주락;김동원
    • 한국약용작물학회지
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    • 제15권4호
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    • pp.261-265
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    • 2007
  • 인삼재배가 가능한 임간의 기후적 특성과 임간재배지내에서의 병해충 발생상황 및 생육상황을 관행재배지와 비교해본 결과는 다음과 같다. 가. 임간재배지의 온도는 관행재배지보다 $1^{\circ}C$ 정도 낮고 습도는 2% 정도 높았으며 토양온도는 $1.9^{\circ}C$ 낮고 토양수분도 11.8%가 낮았다. 임간재배지의 풍속은 관행재배지보다 3배 정도 늦었으며 결로시간은 3.3시간 긴 것으로 나타났다. 특히 일사량은 현저히 부족하였고 강우량도 약간 부족한 것으로 나타났으나 큰 차이는 없었다. 나. 2003년이 2004년과 2005년보다 병해의 발생이 많았고 임간재배지에서의 병해발생이 관행재배지보다 심하였다. 때문에 8월 중순경에 지상부가 거의 다 고사되었다. 임간재배지의 주요 병해충으로는 탄저병, 점무늬병 및 뿌리썩음병이었고, 관행재배지는 위의 병해와 잿빛곰팡이병의 발생이 주를 이루는 것으로 나타났다. 해충으로는 잎별레와 나방류가 가해하는 것으로 조사되었다. 3년근의 생육상황을 비교한 결과 임간재배지에서 자란 인삼의 생육상황이 전반적으로 50% 이상 불량하였고 특히 근중은 87.2% 정도 가벼운 것으로 나타났다.

Study on Electrical Characteristics According Process Parameters of Field Plate for Optimizing SiC Shottky Barrier Diode

  • Hong, Young Sung;Kang, Ey Goo
    • Transactions on Electrical and Electronic Materials
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    • 제18권4호
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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.

수직보조전계 인가방식에 의한 전기영동 전착막의 제작 (Fabrication of EPD Films by Applying a.c Field Assisted Method)

  • 전용우;박성범;소대화
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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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.

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수동루프에 의한 가공송전선로 자계 저감효과 해석 (Analysis of magnetic field mitigation by a passive loop around an overhead power transmission line)

  • 김종형;신명철;이복구;박철원
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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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.

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인가 전압이 Y-TZP의 저온열화에 미치는 영향 (Influence of Applied Electric Field on Low Temperature Degradation of Y-TZP)

  • 장주웅;이홍림;김대준;오남식;이득용
    • 한국세라믹학회지
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    • 제34권12호
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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.

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가스절연 원통형 관로 내의 스페이서 전계 최적화 알고리즘에 관한 연구 (Investigation on Electric Field Optimization Algorithm of Spacer in Gas Insulated System)

  • 김웅식;민석원
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제51권3호
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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.

Continuous Conditional Random Field에 의한 인터넷 쇼핑몰 신규 고객등급 예측 (Prediction of New Customer's Degree of Loyalty of Internet Shopping Mall Using Continuous Conditional Random Field)

  • 안길승;허선
    • 대한산업공학회지
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    • 제41권1호
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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.

$Co_{89}Nb{8.5}Zr{2.5}$ 비정질 박막의 이방성에 미치는 열처리 효과 (Effect of Annealing on the Magnetic Anisotropy of Amorphous $Co_{89}Nb{8.5}Zr{2.5}$Thin Films)

  • 김현식;민복기;송재성;오영우
    • 한국전기전자재료학회논문지
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    • 제11권6호
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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.

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보조전계를 이용한 전기영동 초전도 막의 제작 (Superconducting film fabrication using field Assisted Electrophoresis)

  • 소대화;전용우
    • 한국전기전자재료학회논문지
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    • 제16권2호
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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.