• 제목/요약/키워드: Current pulse

검색결과 1,868건 처리시간 0.034초

Inactivation of N-Type Calcium Current in Rat Sympathetic Neurons

  • Goo, Yong-Sook;Keith S. Elmslie
    • 한국생물물리학회:학술대회논문집
    • /
    • 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
    • /
    • pp.52-52
    • /
    • 1999
  • Inactivation of N-type calcium current has been reported to be voltage dependent (Jones & Marks, 1989) and $Ca^{2+}$ dependent(Cox & Dunlap, 1994). We examined inactivation by recording currents from the same cell both in [B $a^{2+}$]$_{o}$ and [C $a^{2+}$]$_{o}$ in rat sympathetic neurons. With 11 mM internal EGTA, fractional inactivation[l-(current amplitude at the end of 5 sec pulse/peak current amplitude [1-(current amplitude at the end of 5 sec pulse/peak current amplitude)] was larger in $Ca^{2+}$(0.80$\pm$0.07) than in $Ba^{2+}$(0.69$\pm$0.10)(n=31, p<0.001), but the current traces were nicely fitted with two exponential components both in $Ba^{2+}$ and $Ca^{2+}$.(omitted)ted)ted)

  • PDF

6 펄스 사이크로콘버터의 새로운 전류제어법 (A New Current Control Method of the Six-pulse Cycloconverter)

  • 조규민;김영석
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1993년도 하계학술대회 논문집 B
    • /
    • pp.800-802
    • /
    • 1993
  • This paper presents a new current control method of the six-pulse cycloconverter for a variable speed drive system of a large capacity ac mortor. It is necessary for a high performance control as a vector control that the output current scheme of the cycloconverter has a good charistic in transient state. A new proposed current control method is that the output current of the cycloconverter is followed after the current reference directly as fast as possible under any condition. Simulation resualts with the proposed new current control method are shown. As a result the validity of the proposed method is confirmed.

  • PDF

주석-아연 합금도금층의 조성 및 조직에 미치는 파형전류전해의 영향 (The effect of pulse current electrolysis on the composition and themicrostructure of Tin-Zinc electrodeposits)

  • 예길촌;박성진;김대영
    • 한국표면공학회지
    • /
    • 제34권4호
    • /
    • pp.303-312
    • /
    • 2001
  • Composition and microstructure of the tin-zinc alloys electroplated in gluconate bath were studied according to pulse current parameters. The cathode current efficiency increased with both the mean current density and the off-time decrease. Zinc content of the alloy deposits increased with increasing mean current density, while it decreased noticebly with increasing the off-time from 10-30ms to 100-150ms. The preferred orientation of the alloy deposits changed with the increase of peak current density in the sequence of (220)longrightarrow(220)+(420) or (220)+(420)+(321) mixed structure. The equiaxed grain size of the alloy increased with the increase of off-time and the decrease of mean current density.

  • PDF

팔라디움-니켈 합금전착층의 조성 및 조직에 미치는 파형전류인자의 영향 (The effect of pulse parameters on the composition and the structure of Palladium-Nickel alloy electrodeposits)

  • 예길촌;오유청
    • 한국표면공학회지
    • /
    • 제27권5호
    • /
    • pp.285-291
    • /
    • 1994
  • The effects of pulse current parameters on the composition and the microstructure of Pd-Ni alloy electrodeposits were studied. The cathode current efficiency of p.c. electrolysis conditions decreased with increasing both mean and peak current density and was lower than those under D.C. electrolysis condition. Palladium content of Pd-Ni alloy increased with increasing both peak current density and on-time, while it decreased with increasing mean current density and duty cycle. The preferred orientation of Pd-Ni alloys changed with increasing mean current density in the sequence of (111)+(110).(100) or (110)longrightarrow(111)longrightarrow(100) or random distribution of crystal structure. The surface morphology of Pd-Ni alloy changed mainly according to the mean current density and was related to the preferred orientation.

  • PDF

Detection of Deep Subsurface Cracks in Thick Stainless Steel Plate

  • Kishore, M.B.;Park, D.G.;Jeong, J.R.;Kim, J.Y.;Jacobs, L.J.;Lee, D.H.
    • Journal of Magnetics
    • /
    • 제20권3호
    • /
    • pp.312-316
    • /
    • 2015
  • Unlike conventional Eddy Current Test (ECT), Pulsed Eddy Current (PEC) uses a multiple-frequency current pulse through the excitation coil. In the present study, the detection of subsurface cracks using a specially designed probe that allows the detection of a deeper crack with a relatively small current density has been attempted using the PEC technique. The tested sample is a piece of 304 stainless steel (SS304) with a thickness of 30mm. Small electrical discharge machining (EDM) notches were put in the test sample at different depths from the surface to simulate the subsurface cracks in a pipe. The designed PEC probe consists of an excitation coil and a Hall sensor and can detect a subsurface crack as narrow and shallow as 0.2 mm wide and 2 mm deep. The maximum distance between the probe and the defect is 28 mm. The peak amplitude of the detected pulse is used to evaluate the cracks under the sample surface. In time domain analysis, the greater the crack depth the greater the peak amplitude of the detected pulse. The experimental results indicated that the proposed system has the potential to detect the subsurface cracks in stainless steel plates.

전착법을 이용한 Co계 합금박막의 표면형태와 자기특성과의 관계 (Relation between Magnetic Properties and Surface Morphology of Co-Base Alloy Film by Electrodeposition Method)

  • 한창석;김상욱
    • 한국재료학회지
    • /
    • 제27권11호
    • /
    • pp.624-630
    • /
    • 2017
  • In this study, we investigated the overpotential of precipitation related to the catalytic activity of electrodes on the initial process of electrodeposition of Co and Co-Ni alloys on polycrystalline Cu substrates. In the case of Co electrodeposition, the surface morphology and the magnetic property change depending on the film thickness, and the relationship with the electrode potential fluctuation was shown. Initially, the deposition potential(-170 mV) of the Cu electrode as a substrate was shown, the electrode potential($E_{dep}$) at the $T_{on}$ of electrodeposition and the deposition potential(-600 mV) of the surface of the electrodeposited Co film after $T_{off}$ and when the pulse current was completed were shown. No significant change in the electrode potential value was observed when the pulse current was energized. However, in a range of number of pulses up to 5, there was a small fluctuation in the values of $E_{dep}$ and $E_{imm}$. In addition, in the Co-Ni alloy electrodeposition, the deposition potential(-280 mV) of the Cu electrode as the substrate exhibited the deposition potential(-615 mV) of the electrodeposited Co-Ni alloy after pulsed current application, the $E_{dep}$ of electrodeposition at the $T_{on}$ of each pulse and the $E_{imm}$ at the $T_{off}$ varied greatly each time the pulse current was applied. From 20 % to less than 90 % of the Co content of the thin film was continuously changed, and the value was constant at a pulse number of 100 or more. In any case, it was found that the shape of the substrate had a great influence.

Study of Pulse Generation Technique for Serial dual Electrode Detection of Amino Acids and Proteins in Flow Injection Analysis

  • Fung, Ying-Sing;Mo, Song-Ying
    • 분석과학
    • /
    • 제8권4호
    • /
    • pp.575-582
    • /
    • 1995
  • A new analytical procedure using a serial dual electrode detector was developed for the analysis of amino acids and proteins. Bromine was generated at the upstream electrode and detected by the downstream electrode. The presence of amino acids and proteins was shown to lower the downstream current but with no apparent effect on the upstream current. This indirect mode of detection can be applied to the determination of amino acids and proteins which are electrochemically inactive or too large to be accessible to the electrode surface for electron exchange. The method is shown capable to determine various amino acids (cystine, tyrosine, lysine, tryptophan, glycine, methionine and arginine) and proteins (cytochrome c, hemoglobin, HAS, a-Amylase, Conalbumin I, Catalase and Myglobin) with linear working range for amino acids between $10^{-6}$ to $10^{-3}M$ and total proteins between $10^{-7}$ to $10^{-3}M$. The method has been applied for the analysis of amino acids and total protein in food using Flow Injection Analysis with results obtained comparable to those using the traditional analytical procedure. Use of pulse generation technique was shown to produce a more stable flow injection analysis peaks for repetitive determination than the use of conventional constant current method which showed increase of the background current after determination over 200 minutes. The pulse method was found to give stable baseline even after 400 minutes. Thus, the method is shown able to provide a suitable analytical procedure for automatic analysis of amino acids and proteins in food by flow injection analysis.

  • PDF

직류 전원과 펄스 전원을 이용하여 오염된 토양에서의 중금속과 페놀 처리 (Treatment of Heavy Metals and Phenol in Contaminated Soil Using Direct Current and Pulse Voltage)

  • 최창식;홍범의;최희영;이은실;최석순
    • 공업화학
    • /
    • 제27권6호
    • /
    • pp.606-611
    • /
    • 2016
  • 본 연구에서는 오염된 토양 속에 함유된 중금속과 페놀의 처리에 대하여 직류 전원과 펄스 전원을 적용하여 고찰하였다. 직류 전원을 사용하여 오염된 토양을 처리하였을 때 구리, 아연, 비소, 납의 제거 효율은 각각 70, 87, 12, 11%를 나타내었고, 페놀은 85% 이상이 제거되었다. 그리고 펄스 전원을 사용하였을 때 구리, 아연, 비소, 납의 제거효율이 각각 87, 91, 37, 38%이었으며, 페놀은 88% 제거되었다. 이러한 결과들은 펄스 전원을 오염된 토양에 적용하였을 때, 전기삼투 현상은 낮아졌지만 중금속들의 전류이동 속도가 증가함을 알 수 있었다. 또한 토양의 점토 성분에 의한 흡착 능력의 향상으로 인하여 비소와 납의 제거효율이 증가되었다. 따라서 이러한 직류 전원과 펄스 전원을 이용하는 동전기 실험 결과들은 여러 가지 중금속들과 페놀을 처리하는 복원 기술로 유용하게 활용될 수 있을 것이다.

전류인가 방법이 3D-SiP용 Through Via Hole의 Filling에 미치는 영향 (The Effects of Current Types on Through Via Hole Filling for 3D-SiP Application)

  • 장근호;이재호
    • 마이크로전자및패키징학회지
    • /
    • 제13권4호
    • /
    • pp.45-50
    • /
    • 2006
  • 3D package의 SiP에서 구리의 via filling은 매우 중요한 사항으로 package밀도가 높아짐에 따라 via의 크기가 줄어들며 전기도금법을 이용한 via filling이 연구되어왔다. Via filling시 via 내부에 결함이 발생하기 쉬운데 전해액 내에 억제제, 가속제등 첨가제를 첨가하고 펄스-역펄스(PRC)의 전류파형을 인가하여 결함이 없는 via의 filling이 가능하다. 본 연구에서는 건식 식각 방법 중 하나인 DRIE법을 이용하여 깊이 $100{\sim}190\;{\mu}m$, 직경이 각각 $50{\mu}m,\;20{\mu}m$인 2가지 형태의 via을 형성하였다. DRIE로 via가 형성된 Si wafer위에 IMP System으로 Cu의 Si으로 확산을 막기 위한 Ta층과 전해도금의 씨앗층인 Cu층을 형성하였다. Via시편은 직류, 펄스-역펄스의 전류 파형과 억제제, 가속제, 억제제의 첨가제를 모두 사용하여 filling을 시도하였고, 공정 후 via의 단면을 경면 가공하여 SEM으로 관찰하였다.

  • PDF