• Title/Summary/Keyword: pinch effect

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Numerical calculations of characteristics of Argon arc plasma using the control volume method (제어체적법에 의한 Ar 아크 플라즈마의 특성 계산)

  • Kim, Oe-Dong;Ko, Kwang-Cheol;Kang, Hyung-Boo
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1404-1406
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    • 1995
  • In this paper, argon gas was used for numerical analysis of an arc in a cutting plasma torch driven by constant current. We established nozzle-constricting type torch domain and calculated steady state characteristics of argon arc plasma using the control volume method(CVM). For simplicity, we assumed that the flow field is laminar and the local thermodynamic equilibrium(LTE) prevails in all domain regions. We also neglected cathode-fall and anode-fall effects. Considering magnetic pinch effect and viscosity effect, we solved the momentum equation. Voltage drop in the arc column due to input current was calculated from the temperature field obtained by the energy balance equation.

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The skin effect and current distribution characteristics of a coil streaming with high frequency (초고주파전류가 흐르는 코일의 표피효과와 전류분포특성 - 핀치효과 개선용 4각단면 중공코일의 전류흐름특성 -)

  • Jang, S.M.;Seo, J.H.;Lee, H.G.;Hong, J.P.;Lee, J.H.
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.222-224
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    • 1996
  • This paper treats the stream phenomena of high frequency current on the solid-loop coil of which consists the hollow conductor. The governing equation is derived from electromagnetic field theory and the characteristics are analyzed by FEM with 2-D and 3-D. The results may be available data on designing the optimum shape of the coil for the improved pinch effect.

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Deformation of the AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistor characteristics by UV irradiation

  • Lim, Jin Hong;Kim, Jeong Jin;Yang, Jeon Wook
    • Journal of IKEEE
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    • v.17 no.4
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    • pp.531-536
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    • 2013
  • The impact of UV irradiation process on the AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistor was investigated. Due to the high intensity UV irradiation before the gate dielectric deposition, the conductivity of AlGaN/GaN structure and the drain saturation current of the transistor increased by about 10 %. However, the pinch off characteristics of transistor was severely deformed by the process. By comparing the electrical characteristics of the transistors, it was proposed that the high intensity UV irradiation formed a sub-channel under the two dimensional electron gas of AlGaN/GaN structure even without additional impurity injection.

Direct Numerical Simulation of Flow Characteristics of the Fluid Laden with Many Particles (입자가 포함된 유체의 유동특성에 대한 직접수치해석)

  • Cho, Sang-Ho;Choi, Hyoung-Gwon;Yoo, Jung-Yul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.9
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    • pp.1327-1334
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    • 2003
  • Flow characteristics of the fluid laden with many particles in the two-dimensional channel are investigated using the Navier-Stokes equations coupled with the equation of motion of particles by direct numerical simulation. A four-step fractional step method with Crank-Nicolson scheme and ALE technique is used for P2P1 mixed finite element method. The motion and distribution of particles in the fluid is virtually described as a result of direct numerical simulation and the increase of viscosity is compared with theoretical equations. The effect of channel height on the relative viscosity and the tubular pinch effect are discussed.

Effects of Ginseng Total Saponins on the Analgesia and Tolerance Development of Pentazocine (펜타조신의 진통작용 및 내성형성에 미치는 인삼 사포닌의 효과)

  • Kim, Hack-Seang;Ann, Sun-Hee;Seong, Yeon-Hee;Kim, Sun-Hye;Oh, Ki-Wan
    • Journal of Ginseng Research
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    • v.16 no.2
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    • pp.93-98
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    • 1992
  • This study examined the Influence of ginseng total saponins (GTS) on the analgestic action and tolerance development of pentazocine in mice. Pentazocine prolonged the latency to response in the tail flick rather than in the tail pinch test. The analgesic effect of pentaEocine was antagonized by naloxone and completely eliminated by pretreatment u·ith f-chlorophenylalanine (PCPA). GTS provented the pentasocine-incuced analgesia ann inhibited the development of tolerance to pentazocine. The antagonistic effect of GTS on the pentazocine-induced analgesia was abolished by 5-HTP, but not by L-DOPA. These results suggest that GTS inhibits the analgesic action of pentazocine by the interaction with serotonergic neuron.

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Analysis of the skin effect on the coil with high frequency current source (고주파 전원에 의한 코일의 표피효과 해석)

  • Jang, S.M.;Seo, J.H.;Kim, H.K.;Lee, J.H.
    • Proceedings of the KIEE Conference
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    • 1997.07a
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    • pp.288-290
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    • 1997
  • The electromagnetic theory is applicated on the field of electromagnetic continuous casting(EMC). This paper treats the stream phenomena of high frequency current on the solid-loop coil of which consists the hollow conductor. The governing equation is derived from elctromagnetic field theory and the characteristics are analyzed by FEM. The results may be availabe data on designing the optimum shape of the coil for the improved pinch effect.

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A Study on Breakdown Voltage of GaAs Power MESFET's (GaAs Power MESFET의 항복전압에 관한 연구)

  • 김한수;김한구;박장우;기현철;박광민;손상희;곽계달
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.7
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    • pp.1033-1041
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    • 1990
  • In this paper, under pinch-off conditions, the gate-drain breakdown voltage characteristics of GaAs Power MESFET's as a function of device parameters such as channel thickness, doping concentration, gate length etc. are analyzed. Using the Green's function, the gate ionic charge induced by the depleted channel ionic charge is calculated. The impact ionization integral by avalanche multiplication between gate and drain is used to investigate breakdown phenomena. Especially, the localized excess surface charge effect as well as the uniform surface charge effect on breakdown voltage is considered.

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Loop Suture Technique for Flexor Digitorum Profundus Tendon Repair in the Insertion Site (고리 봉합법을 이용한 심부 수지 굴건 종지부에서의 건봉합)

  • Lee, Kyu-Cheol;Lee, Dong-Chul;Kim, Jin-Soo;Ki, Sae-Hwi;Roh, Si-Young;Yang, Jae-Won
    • Archives of Plastic Surgery
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    • v.37 no.5
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    • pp.650-658
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    • 2010
  • Purpose: In the case of repair for far distal parts of FDP (Flexor digitorum profundus) division, the method of either pull-out suture or fixation of tendon to the distal phalanx is preferred. In this paper, the results of a modified loop suture technique used for the complete division of FDP from both zone 1a and distal parts of zone 1b in Moiemen classification are presented. Methods: From July 2006 to July 2009, the modified loop suture technique was used for the 10 cases of FDP in complete division from zone 1a and distal parts of zone 1b, especially where insertion sites were less than 1 cm apart from a tendon of a stump. In a suture technique, a loop is applied to each distal and proximal parts of tendon respectively. Core suture of 2-strand and epitendinous suture are done with PDS 4-0. Out of 10 patients, the study was done on 6 patients who were available for the followup. The average age of the patients was 49.1 years (in the range from 26 to 67). 5 males and 1 female patients were involved in this study. There were 3 cases with zone 1a and distal parts of zone 1b. The average distance to the distal tendon end was 0.6 cm. There were 5 cases underwent microsurgical repair where both artery and nerve divided. One case of only tendon displacement was presented. The dorsal protective splint was kept for 5 weeks on average. The results of the following tests were measured: active & passive range of motion, grip strength test, key pinch and pulp pinch test. Results: The follow-up period on average was 11 months, in the range from 2 to 20 months. There was no case of re-rupture, but tenolysis was performed in 1 cases. In all 6 cases, the average active range of motion of distal interphalangeal joint was 50.8 degree. The grip strength (ipsilateral/contralateral) was measured as 88.7% and the pulp pinch test was 79.2% as those of contralateral side. Flexion contracture was presented in 2 cases (15 degree on average) and there was no quadrigia effect found. Conclusion: Despite short length of tendon from the insertion site in FDS rupture in zone 1a and distal parts of zone 1b, sufficient functional recovery could be expected with the tendon to tendon repair using the modified loop suture technique.

Eco-Industrial Park (EIP) Development and Key Technologies for Clean Production (청정 생산을 위한 생태산업단지 구축과 주요기술)

  • Yoo, ChangKyoo;Heo, Soon-Ki;Yoo, Dong Joon;Lee, SeungJun;Shin, Ji Na;Park, Yong Joon;Yoon, Hack Mo;Chun, Hee Dong;Moon, Jeong Ki;Lee, In-Beum
    • Korean Chemical Engineering Research
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    • v.43 no.5
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    • pp.549-559
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    • 2005
  • Sustainable industrial development which can minimize an ecological effect by the mankind exertion is recently interested due to an environmental contamination and a resource exhaustion problem. An eco-industrial park (EIP) is a community of manufacturing and service businesses seeking enhanced environmental and economic performance through collaboration in managing environmental and resource issues, including energy, water, and materials. EIP developments which improve a production plant within an eco-friendly greenfield and design a new industrial ecosystem are accomplished recently, which can efficiently re-use the waste and resources from each company within EIP. In this review, the outside and domestic case studies of EIP and cornerstone technologies to develop the EIP, such as energy integration, waste reuse, mass flow analysis, water pinch, and life cycle assessment, are summarized.

The Effect of Upper Extremity Exercise Program for Hemiplegic Stroke Patients (뇌졸중 편마비 환자를 위한 상지운동프로그램의 효과)

  • Park, Young-Rye;Kim, Keum-Soon;Choi, Kyung-Sook
    • Korean Journal of Adult Nursing
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    • v.16 no.4
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    • pp.626-635
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    • 2004
  • Purpose: The purpose of this study was to explain the effects of upper extremity exercise program on hemiplegic stroke patients. Method: The research was designed by a non-equivalent pretest-posttest way. The data were collected from February to August 2003 at a community health center located in Seoul. The study subjects were a conveniently selected group of 27 hemiplegic patients. The subjects were divided into two groups, the experimental group and the control group. 14 subjects were assigned to the experimental group in which the subjects did the upper extremity exercise training for 2 hours once a week during four weeks, while 13 subjects were assigned to the control group. The outcomes were evaluated on the basis of the upper extremity motor ability(hand power, pinch power, upper extremity ROMs), amount of motor use and the degree of depression. Result: 1. After treatment, the motor abilities of the affected upper extremity(hand power, pinch power, ROMs of wrist flexion/extension, shoulder extension) were significantly different between the two groups. However, there were no significant differences in elbow and shoulder flexion between experimental and control group. 2. After treatment, amount of motor use of affected upper extremity were significantly different between the two groups. 3. After treatment, the degree of depression were significantly different between the two groups. Conclusion: In considering these results, the upper extremity exercise program could be effective for hemiplegic patients by improving the function of their upper extremity. Long-term studies are needed to determine the effects of upper extremity exercise program.

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