• Title/Summary/Keyword: 토크비

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Effects of lidocaine on haematology and blood chemistry in the carp(Cyprinus carpio) (Lidocaine이 잉어(Cyprinus carpio)의 혈액성상에 미치는 영향)

  • Chung, Joon-Ki;Chung, Soon-Yoon;Lee, Tae-Woong;Choi, Dong-Lim
    • Journal of fish pathology
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    • v.7 no.1
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    • pp.53-62
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    • 1994
  • The effects of lidocaine on the parameters of haematology and blood chemistry were investigated in the carp(Cyprinus carpio). At low concentrations(100 and 200 ppm) of lidocaine, no significant changes in the parameters of haematology and blood chemistry were observed during recovery period from the treatment of lidocaine. However, at high concentrations(300 and 400 ppm) of lidocaine, red blood cell(RBC) and hematocrit(Ht) value, plasma glucose concentration, and the activity of lactate dehydogenase(LDH) were markedly increased compared with the controls. These increases were maintained for up to 60 min. Based on these results, it is suggested that lidocaine is generally not toxic to fish but has shown the physiological stress responses at high concentrations.

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Effects of Dietary Protein and Calcium Levels on Hematological Properties and Renal Functions of the Pb-administered Rats. (식이내 단백질과 칼슘의 수준이 납중독된 흰쥐에 혈액학적 성상 및 신기능에 미치는 영향)

  • 이정숙;조수열
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.20 no.4
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    • pp.337-345
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    • 1991
  • This study was designed to investigate the effects of dietary protein ana calcium levels on hematological properties and renal functions of the Pb-administered rats. Male Sprague-Dawley rats were assigned to a 3$\times$3$\times$2 factorial design with 3 levels of protein (40%, 16%, 6%), 3 levels of Ca (1.2%, 0.6%, 0.12%) and 2 feeding Periods (3 and 7 Weeks). The Control group was included separately, The rats were exposed to the drinking water containing 2, 000ppm of lead. Hematocrit, hemoglobin content and RBC count were lower in the Pb-added groups than in the control group and were reduced with decreasing dietary protein and Ca levels. Urinary-aminolevulinic acid was higher in the Pb-added groups than in the control group and increased with decreasing dietary Ca level. However, urinary glucose was higher in the Pb-added groups than in the control group and enhanced with decreasing dietary protein and Ca levels. Creatinine celarance was not affected by the Pb administration when the rats fed the diet containing sufficient protein and Ca.

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Optimal Design of Five-Phase Permanent Magnet Assisted Synchronous Reluctance Motor for High Speed Railroad Traction System (고속철도 추진용 5상 영구자석 저감형 동기전동기의 최적설계)

  • Baek, Jeihoon;Kim, Myung Yong;Yi, Kyung-Pyo
    • Journal of the Korean Society for Railway
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    • v.20 no.5
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    • pp.588-594
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    • 2017
  • Permanent magnet assisted synchronous reluctance motors (PMa-SynRM) show higher efficiency and power density compared to conventional induction motors for high speed railroad traction systems. Furthermore, 5-phase PMa-SynRMs have lower torque ripple and higher power density than 3-phase systems. Therefore, the 5-phase PMa-SynRM is suitable for high-speed railway traction systems. In this study, 3kw 3-phase and 5-phase PMa-SynRM models were optimized using lumped parameter model and genetic algorithm, and their characteristics were compared. The optimized models are fine-tuned using finite element analysis. The final models of the 3-phase and 5-phase PMa-SynRMs are fabricated and tested to verify the analysis results.

Properties of SBR Nanocomposites Reinforced with Organoclay/Carbon Black Dual Phase Fillers (카본 블랙/유기화 클레이로 보강된 SBR 나노 복합재료: 모폴로지와 기계적 물성)

  • Kang, B.S.;Kim, W.
    • Elastomers and Composites
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    • v.42 no.1
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    • pp.9-19
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    • 2007
  • In this study, SBR (Styrene-butadiene rubber: solid content: 25 wt%) nanocomposites reinforced with carbon/organoclay(C18-MMT) were manufactured by a latex method. The SBR nanocomposites was made with the dual phase fillers. The mixing ratios, i.e. carbon black/C18-MMT, were 50/0, 49/1, 48/2, 47/3, 45/5, 44/6, 40/10. Total filler content of compounds was restricted to 50 phr. Cure characteristics and mechanical properties of SBR nanocomposites with carbon black and C18-MMT were evaluated. The SBR nanocomposites containing 49/1 ratio of carbon black/C18-MMT showed good dispersity and excellent values of ODR torque, tensile strength, modulus and tear energy. It was found that the improvement of the mechanical properties was mainly due to the reinforcing effect, i.e., the improvement of dispersion of silicates in the rubber matrix.

A Study on Simulation-based Optimization for Wind Turbine Controller Tuning (시뮬레이션 기반의 풍력발전제어시스템 최적화 기법에 관한 연구)

  • Jeon, Gyeong-Eon;No, Tae-Soo;Kim, Guk-Seon;Kim, Ji-Yon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.16 no.5
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    • pp.503-510
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    • 2011
  • This paper presents a method of optimizing the blade pitch and generator torque controllers which have been already designed for an existing wind turbine generator system. Since the highly nonlinear and uncertain characteristics of the wind turbine generator can not be fully considered in the controller design phase, some parameters such as control gains must be tuned during the field implementation phase. In this paper, nonlinear simulation software, which is based high fidelity wind turbine model, and optimization technique are effectively combined and used to tune a set of gains for the blade pitch and the generator torque controllers. Simulation results show that the baseline controllers can be effectively optimized to reduce the errors in wind turbine rotor speed and generator power output controls as well as twisting of the high and low speed shafts.

Structure Design and Experimental Appraisal of the Drag Force Type Vertical Axis Wind Turbine (수직축 항력식 풍력터빈의 구조설계 및 실험평가)

  • Kim Dong-Keon;Keum Jong-Yoon;Yoon Soon-Hyun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.3 s.246
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    • pp.278-286
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    • 2006
  • Experiments were conducted to estimate the performance of drag force type vertical axis wind turbine with an opening-shutting rotor. It was operated by the difference in drag force generated on both sides of the blades. The rotational speed was measured by a tachometer in a wind tunnel and the tunnel wind speed was measured by using a pilot-static tube and a micro manometer. The performance test for a prototype was accomplished by calculating power, power coefficient, torque coefficient from the measurement of torque and rpm by a dynamometer controller. Various design parameters, such as the number of blades(B), blade aspect ratio(W/R), angle of blades$(\alpha)$ and drag coefficient acting on a blade, were considered for optimal conditions. At the experiment of miniature model, maximum efficiency was found at N=15, $\alpha=60^{\circ}$ and W/R=0.32. The measured test variables were power, torque, rotational speed, and wind speeds. The data presented are in the form of power and torque coefficients as a function of tip-speed ratio V/U. Maximum power was found in case of $\Omega=0.33$, when the power and torque coefficient were 0.14 and 0.37 respectively. Comparing model test with prototype test, similarity law by advance ratio for vertical axis wind turbine was confirmed.

Flow Characteristics and Drag Reduction at Different Pressures of Counterflow Air Jets in Supersonic Flow (초음속 환경에서 역분사 공기 제트의 압력 변화에 따른 유동 특성 및 항력 감소)

  • Choi, Jongin;Lee, Jaecheong;Kang, Seungwon;Huh, Hwanil
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.1
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    • pp.58-65
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    • 2018
  • To improve the performance of high-speed vehicles, various studies have been carried out on the head of vehicles. In this study, tests are conducted on flow characteristics and drag reduction using counterflow air jets in supersonic flow. The flow is visualized by the Schlieren method using a high-speed camera, and the drag is measured using a torque sensor according to the injection pressure conditions. The results of the measurements indicate that the flow changes from unsteady state to steady state for injection pressure ratios between 1.58 and 1.70, and drag reduction is observed as the pressure of the counterflow air jets increases.

The Numerical Analysis of the Aeroacoustic Characteristics for the Coaxial Rotor in Hovering Condition (동축반전 로터의 제자리 비행 공력소음 특성에 관한 수치 해석적 연구)

  • So, Seo-Bin;Lee, Kyung-Tae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.49 no.8
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    • pp.699-708
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    • 2021
  • In this paper, the aerodynamic and aeroacoustic characteristics that vary depending on the rotation axial distance between the upper and lower rotor, which is one of the design parameters of the coaxial rotor, is analyzed in the hovering condition using the computational fluid dynamics. Aerodynamic analysis using the Reynolds Averaged Navier Stokes equation and the aeroacoustic analysis using the Ffowcs Williams ans Hawkings equation is performed and the results were compared. The upper and lower rotor of the coaxial rotor have different phase angle which changes periodically by rotation and have unsteady characteristics. As the distance between the upper and lower rotors increased, the aerodynamic efficiency of the thrust and the torque was increased as the flow interaction decreased. In the aeroacoustic viewpoint, the noise characteristics radiated in the direction of the rotational plane showed little effect by axis spacing. In the vertical downward direction of the axis increased, the SPL maintains its size as the frequency increases, which affects the increase in the OASPL. As the axial distance of the coaxial rotor increased, the noise characteristics of a coaxial rotor were similar with the single rotor and the SPL decreased significantly.

Study on the Shift Characteristics of a 2speed Manual Transmission apply to V-Blet (V-blet를 적용한 2단 수동변속기의 변속특성에 관한 연구)

  • Youm, Kwang-wook
    • Journal of the Korean Institute of Gas
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    • v.24 no.6
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    • pp.55-60
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    • 2020
  • As research and development of eco-friendly vehicles are expanding worldwide, additional devices of vehicles are reduced or deleted to increase the mileage, or research is being conducted to reduce weight. Among them, the multi-stage transmission that was applied to the internal combustion engine vehicle was deleted and replaced with a reducer, and the initial driving power is secured by increasing the torque through the control of the motor output value. However, since frequent motor speed change can result in a load increase, this study attempts to develop a compact and lightweight manual two-stage reducer with a general reducer structure. Therefore, a two-speed transmission with two gear ratio was designed by inserting a large gear and a small gear in a structure with a parallel shaft to connect the gears with a V-belt in the form of a parallel shaft reducer, and setting the gear ratio of the low and high gears respectively. In addition, power performance according to the rotational speed and load of the transmission was checked through a test, and the heat generation characteristics generated during driving were checked to verify the validity of the transmission.

Validation for Performance and Hub Vibratory Load Analyses of Lift-offset Coaxial Rotors in Wind-Tunnel Tests (풍동 시험용 Lift-offset 동축 반전 로터에 대한 성능 및 허브 진동 하중 해석의 검증 연구)

  • Lee, Yu-Been;Park, Jae-Sang
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.7
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    • pp.497-505
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    • 2022
  • Performance and hub vibratory load analyses for a lift-offset coaxial rotor are conducted using a rotorcraft comprehensive analysis code, CAMRAD II. The lift-offset coaxial rotor is trimmed to match the total rotor thrust(lift-offset coaxial rotor's thrust) or the individual rotor thrust(upper and lower rotor thrusts, respectively) in this study. The individual rotor's lift and torque, and effective rotor lift to drag ratio for the total rotor are investigated for various advance ratios and lift-offset values. The two result sets with different trim methods are similar to each other and they are correlated well with the wind-tunnel test results. Therefore, the present study using CAMRAD II validates successfully the aeromechanics modeling and analysis techniques for the lift-offset coaxial rotor.