• Title/Summary/Keyword: N.D.C method

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Cu/Si/Cu Ohmic contacts to n-type 4H-SiC (n형 4H-SiC의 Cu/Si/Cu 오옴성 접합)

  • 정경화;조남인;김민철
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.11a
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    • pp.73-77
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    • 2002
  • Characteristics of Cu/Si/Cu ohmic contacts to n-type 4H-SiC were investigated systematically. The ohmic contacts were formed by rf sputtering of multi layer Cu/Si/Cu sputtered sequentially. The annealings were peformed With 2-Step using RTP in vacuum ambient. The specific contact resistivity($\rho$c), sheet resistance(Rs), contact resistance(Rc), transfer length(L$_{T}$) were calculated from resistance(R$_{T}$) versus contact spacing(d) measurements obtained from TLM(transmission line method) structure. Best results were obtained for a sample annealed at vacuum as $\rho$c = 1.0x10$^{-6}$ $\Omega$$\textrm{cm}^2$, Rc = 2$\Omega$ and L$_{T}$ = 1${\mu}{\textrm}{m}$. The physical properties of contacts were examined using XRO and AES. The results showed that copper silicide was formed on SiC and Cu was migrated into SiC.o SiC.

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A Case of Peripheral Neuropathy after Acupuncture (의인성(醫因性) 말초신경병증(末梢神經病症) 치험(治驗) 1례(例))

  • Lee, Kyung-Min;Seo, Jung-Chul;Lim, Seong-Chul;Jung, Tae-Young;Han, Sang-Won
    • Korean Journal of Acupuncture
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    • v.21 no.3
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    • pp.137-146
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    • 2004
  • Objective : The purpose of this study is to report the patient with peripheral neuropathy, who improved by Oriental medical treatment. Methods : The patient was managed by acupuncture, moxibustion, physical treatment and herbal medicine. We checked digital infrared thermographic imaging(D.I.T.I.), electromyography(E.M.G.), nerve conduction velocity(N.C.V.), deep tendon reflex(D.T.R.), sensory recover area and range of motion(R.O.M.) of knee & ankle. Results : After 6 week treatment, clinical sign(the movement and sense of leg) of improvement was appeared. Also E.M.G., N.C.V., D.T.R. and D.I.T.I. was recovered to nearly normal range. Conclusion : The results suggest that combination of acupunture, moxibustion and herbal medicine is good method for treatment of peripheral neuropathy. But further studies may be required to concretely prove the effectiveness of this methods for treating peripheral neuropathy.

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Development of Partial Discharge Measuring Sensor and System for Mold Transformer (몰드변압기용 부분방전 측정 센서 및 시스템 개발)

  • Kang, D.S.;Sun, J.H.;Cho, K.H.;Lee, S.M.;Yun, Y.H.;Lee, D.Z.;Oeu, S.Y.;Kim, J.H.;Choi, K.N.
    • Proceedings of the KIEE Conference
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    • 2005.11c
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    • pp.99-102
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    • 2005
  • In order to development of diagnosis system for mold transformer, partial discharge measurement technique is recommended the best effective method for the evaluation of insulation condition on high voltage winding part. However, this technique was not applied to mold transformer yet. The purpose of this paper is to describe the method of partial discharge measurement for mold transformer with coupling sensor and measuring system. As we reviewed and developed the on-line partial discharge test technique, ceramic coupling sensor, measuring system, terminal box and index parameters.

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The Error and the Graphical Presentation form of the Binocular Vision Findings (양안시기능 검사 값의 오차와 그래프 양식)

  • Yoon, Seok-Hyun
    • Journal of Korean Ophthalmic Optics Society
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    • v.12 no.3
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    • pp.39-48
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    • 2007
  • The stimulus of accommodation A, the stimulus of convergence C and the prism diopter ${\Delta}$ are reviewed and redefined more obviously. How the A and C are managed in the practice are reviewed and summarized. As a result, the common practical process of the binocular vision findings is most suitable in the case of the $l_c=26.67mm$, where the near distance is measured from the test lens to the near target and its value is 40 cm and the average of the P.D equal to 64 mm. The $l_c$ is the distance between the test lens and the center of rotation. Those values were used at calculating the various values in this paper. The error of the stimulus of accommodation values which are evaluated by the practically used formula (5) are calculated. Where the distance between lens and the principle point of eye is 15.07 mm ($=l_H$). The incremental stimulus of convergence values P' caused by the addition prism $P_m$ are evaluated by the recursion computation method. The P' are varied with the $P_m$, the distance $p_c$ between the prism and the center of rotation, the initial convergence value (or inverse target distance) $C_o$ and the refractive index n of the prism material. The recursion computation method and the other formulas are described in detail. In this paper n=1.7 is used. The two factors by which the P' is increased are exist. The one which is major is the property by which the values of convergence whose unit is ${\Delta}$ are not added in the generally way. The other is the that the actual power of the prism is varied with the angle of incidence light. And the P' is decreased remarkably by an increase in the $p_c$ and $C_o$. The $P^{\prime}/P_m$ are calculated and graphed which are varied with the $p_c$ and $C_o$, where the $P_m=20{\Delta}$, P.D=64 mm and n=1.7. The index n dependence of the $P^{\prime}/P_m$ is negligible (refer to fig. 6). The $p_c$ are evaluated at which the P' equal to the $P_m$ for various $P_m$ (refer to table 1). The actual values of the stimulus of convergence and accommodation which are manipulated simply in the practice are calculated. Two graphical forms are suggested. The one is like as the commonly used one. But the stimulus of convergence and of accommodation values in the practice are positioned at the exact positions when the graphic is made (refer to fig. 9). The other is the form that the incremental stimulus of convergence values caused by the addition prisms are represented at actual positions (refer to fig. 11).

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Estimation of Energetic and Charge Transfer Properties of Iridium(III) Bis(2-phenylpyridinato-N,C2')acetylacetonate by Electrochemical Methods

  • Cha, Joeun;Ko, Eun-Song;Shin, Ik-Soo
    • Journal of Electrochemical Science and Technology
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    • v.8 no.2
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    • pp.96-100
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    • 2017
  • Iridium(III) bis(2-phenylpyridinato-$N,C^{2^{\prime}}$)acetylacetonate ($(ppy)_2Ir(acac)$), a green dopant used in organic light-emitting devices (OLEDs), was subjected to electrochemical characterization to estimate its formal oxidation potential ($E^{o^{\prime}}$), HOMO energy level ($E_{HOMO}$), electron transfer rate constant ($k^{o^{\prime}}$), and diffusion coefficient ($D_o$). The employed combination of voltammetric methods, i.e., cyclic voltammetry (CV), chronocoulometry (CC), and the Nicholson method, provided meaningful insights into the electron transfer kinetics of $(ppy)_2Ir(acac)$, allowing the determination of $k^{o^{\prime}}$ and $D_o$. The quasi-reversible oxidation of $(ppy)_2Ir(acac)$ furnished information on $E^{o^{\prime}}$ and $E_{HOMO}$, allowing the latter parameter to be easily estimated by electrochemical methods without relying on expensive and complex ultraviolet photoemission spectroscopic (UPS) measurements.

A Study on the Oxide Semiconductor $ITO_{(n)}/Si_{(p)}$ Solar Cell(II) (산화물 반도체 $ITO_{(n)}/Si_{(p)}$ 태양전지에 관한 연구(II))

  • Kim, Y.W.;Jo, Y.H.;Son, J.H.;Lee, D.C.
    • Proceedings of the KIEE Conference
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    • 2002.06a
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    • pp.184-186
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    • 2002
  • $ITO_{(n)}/Si_{(p)}$ solar cell was fabricated by vaccum deposition method under the resistance heating with substrate temperature kept about 200[$^{\circ}C$] and than their properties are investigated. The cell charateristics can be improved by annealing but are deteriorated at temperature above 650[$^{\circ}C$] for longer than 15[min].

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New Crystal form of Valsartan Dipotassium Salt (발사르탄 이칼륨염의 신규 결정형)

  • Seo, Sung-Ki;Kim, Dae-Duk;Oh, Eui-Chaul
    • Journal of Pharmaceutical Investigation
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    • v.39 no.3
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    • pp.173-176
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    • 2009
  • A new crystal form of valsartan dipotassium was isolated by recrystallization using the one-pot method. The new crystal form was identified as a monohydrate form ($C_{24}H_{27}N_5O_3K_2.H_2O$) and characterized by diffential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray powder diffractometry (PXRD). The new crystal data demonstrated to be clearly different from those known for the tetrahydrate form ($C_{24}H_{27}N_5O_3K_2.4H_2O$). It was observed that the monohydrate of vasartan dipotassium salt was completely dissolved in water within 1 hour and its dissolution rate was much faster than anhydrous free form of valsartan.

Copper Ohmic Contact on n-type SiC Semiconductor (탄화규소 반도체의 구리 오옴성 접촉)

  • 조남인;정경화
    • Journal of the Microelectronics and Packaging Society
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    • v.10 no.4
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    • pp.29-33
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    • 2003
  • Material and electrical properties of copper-based ohmic contacts on n-type 4H-SiC were investigated for the effects of the post-annealing and the metal covering conditions. The ohmic contacts were prepared by sequential sputtering of Cu and Si layers on SiC substrate. The post-annealing treatment was performed using RTP (rapid thermal process) in vacuum and reduction ambient. The specific contact resistivity ($p_{c}$), sheet resistance ($R_{s}$), contact resistance ($R_{c}$), transfer length ($L_{T}$), were calculated from resistance (RT) versus contact spacing (d) measurements obtained from TLM (transmission line method) structure. The best result of the specific contact resistivity was obtained for the sample annealed in the reduction ambient as $p_{c}= 1.0 \times 10^{-6}\Omega \textrm{cm}^2$. The material properties of the copper contacts were also examined by using XRD. The results showed that copper silicide was formed on SiC as a result of intermixing Cu and Si layer.

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Hydrogen Permeance of Silica Membrane Prepared by Chemical Vapor Deposition Method on an $\alpha$-Alumina Support Tube (기상 화학증착법에 의해 $\alpha$-Alumina 지지관 상에 제조한 Silica막의 수소투과 특성)

  • 김성수;이재홍;서동수;박상욱;서봉국
    • Journal of Environmental Science International
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    • v.7 no.5
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    • pp.669-677
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    • 1998
  • A porous $\alpha$-alumina tube of 2.5 mm O.D. and 1.9 mm I.D. was used as the support of an inorganic membrane. Macropores of the tube, about 150 nm in size, were plugged with silica formed by thermal decomposition of tetraethylorthosilicate at $600^{\circ}C$. The forced cross-flow CVD method that reactant was evacuated through the porous wall of the support was very effective in plugging macropores. The H$_2$ permeance of the prepared membrane was of the order of $10^{-8}/ molㆍs^{-1}/ㆍm^{-2}/. Pa{-1}$/, while the $N_2$ permeance was below $10^{-11}/ molㆍs^{-1}/ㆍm^{-2}/ㆍPa^{-1}$/ at $600^{\circ}C$. This was comparable to that of silica-modified Vycor glass whose size was 4 nm.

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High frequency partial discharge measurement by metal foil electrode (박전극을 이용한 고주파 부분방전 측정 연구)

  • Kim, C.S.;Shin, D.S.;Lee, C.Y.;Kim, J.N.;Baek, J.H.;Kim, D.W.;Park, W.K.
    • Proceedings of the KIEE Conference
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    • 1999.11d
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    • pp.1081-1083
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    • 1999
  • The capacitive coupling technique has been used as conventional method for PD detection on the power cable line. Recently, however PD measurement using by high frequency is known to have an excellent sensitivity comparison with low frequency on-site. In this paper, the high frequency characteristic of two type of metal foil sensor was studied and the technique was proved to be more effective diagnostic method than conventional method for qualification of EHV cable and accessories.

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