• Transactions on Electrical and Electronic Materials
• /
• v.2 no.4
• /
• pp.1-6
• /
• 2001

In this paper, a 1.5 V high-gain high-frequency CMOS complementary operational amplifier is presented. The input stage of op-amp is designed for supporting the constant transconductance on the Input stage by consisting of the parallel-connected rail-to-rail complementary differential pairs. And consisting of the class-AB rail-to-rail output stage using the concept of elementary shunt stage and the grounded-gate cascode compensation technique for improving the low PSRR which was a disadvantage in the general CMOS complementary input stage, the load dependence of open loop gain and the stability of op- amp on the output load are improved, and the high-gain high-frequency operation can be achieved. The designed op-amp operates perfectly on the complementary mode with the 180° phase conversion for a 1.5 V supply voltage, and shows the DC open loop gain of 84 dB, the phase margin of 65°, and the unity gain frequency of 20 MHz. In addition, the amplifier shows the 0.1 % settling time of .179 ㎲ for the positive step and 0.154 ㎲ for the negative step on the 100 mV small-signal step, respectively, and shows the total power dissipation of 8.93 mW.

• Proceedings of the IEEK Conference
• /
• 2003.07b
• /
• pp.1117-1120
• /
• 2003

In this paper, a 1.5V CMOS high frequency operational amplifier for high frequency signal processing systems is presented. For obtaining the high gain and the high unity gain frequency with the 1.5V supply voltage, the op-amp is designed with simple two stages which are consisting of the rail-to-rail differential input stage and the class-AB output stage. The designed op-amp operates with the 1.5V supply voltage, and shows well the push-pull class-AB operation. The simulation results show the DC open loop gain of 77dB and the unity gain frequency of 100MHz for the 1㏁ ┃ 10pF load. When the resistive load R$_1$. is varied from 1㏁ to 1 ㏀, the DC open loop gain decreases by only 4dB.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.12
• /
• pp.1582-1590
• /
• 2004

The purpose of this study is to show the existence of optimal operation conditions for minimum fuel consumption of the gas turbine based combined cycle cogeneration power plant. Optimal operational condition means the optimal distribution of the power generated by each gas turbine and the heat generated by each HRSG. Total fuel consumption is calculated by the sum of the fuels for gas turbines and supplementary boiler. Fuel consumption is calculated by numerical methods of energy equations which contain the power generated from gas and steam turbines, the heat generated by HRSG and the heat extracted from high pressure steam turbine.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.13 no.4
• /
• pp.340-351
• /
• 1988

Up to now, hybrid torque/position control of robot manipulator have been researched under the assumption that link mass and/or load are known. This paper proposes a torque and position control method under unknown mass of links or load of a robot manipulator and the method extend control in joint space to control in operational space. In the method, known parameters are used to estimate unknown parameter. We illustrate the theory with some simulations and show that the result is effective.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.5
• /
• pp.326-333
• /
• 2009

Design life-time of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Bladed. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2880-2885
• /
• 2008

Design lifttime of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Blade. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.11a
• /
• pp.147-154
• /
• 2008

A simulation program is developed for the optimal design of small scale district heating and cooling system. Main features for the simulation program are the reliability and the easiness for the optimal design of the DHC(District Heating and Cooling) systems. In order for implementing those features, the operational characteristics according to the prime movers is modeled based on the materials of efficiency as a function of operational load. The unit energy load model is also developed extensively for several building types, of which the corresponding district consist, such as apartment complex, hotel, hospital, buildings for business and commercial use respectively. The specific features and the overall procedure of the simulation are described in brief in this paper. The results of the simulation for several test cases will be presented in subsequent study.

• Journal of Environmental Health Sciences
• /
• v.17 no.1
• /
• pp.13-19
• /
• 1991

Interest in the studies of diesel exhaust emission has been increasing by the expected increase in the use of diesel powered automobiles out of concideration of fuel economy. It was well known that diesel exhaust emission was mutagenic in the bioassay as Ames test. The authors tried to find out the cytogenetic effect of diesel exhaust emission by the operational condition of engine such as speed and load. For the investigation of those effects, 66 male mice of ICR strain were used. The benzene-ethanol extracts of diesel exhaust emission were injected intra peritoneum 25rng/kg and 50mg/kg respectively. To evaluate the cytogenetic effect, mouse bone marrow micronucleus test was carried out. The frequency of micronucleus was different among the various groups according to the operational conditions of engine. The frequency of micronucleus in idling group was the highest of all the groups the subgroup of 50mg/kg showed the rate of 1.30%, 25rng/kg subgroup 0.55%. And the group of 2000rpm with 50% load showed the lowest rate of micronucleus appearance as 0.20% and 0.15%. In general, the frequency of micronucleus was shown higher in propotion to load and was shown inversely proportional to speed.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.825-832
• /
• 2008

A simulation program is developed for analysing thermal networking process between the District heating and the CES(Community Energy Supply) systems. The effects of thermal networking on the District heating facilities previously being operated are implemented using mathematical correlations in terms of the fuel consumption and energy load such as heating and electricity. The operational characteristics according to the prime movers is modeled based on the materials of efficiency as a function of operational load. The unit energy load model is also developed extensively for several building types such as apartment complex, hotel, hospital, buildings for business and commercial use respectively. The specific features of the newly developed program in simulation of thermal networking process in district heating is described in terms of the reliability and the easiness for operating it etc.

• Aerospace Engineering and Technology
• /
• v.1 no.1
• /
• pp.1-7
• /
• 2002

This paper describes the analysis method about the dynamic characteristics and vibratory load through HDS(Helicopter Design Study). To analyze the dynamic characteristics of helicopter rotor blade, the natural frequencies and modes are calculated according to rotor operational speed(Ω). Generally the proximity of rotor natural frequency and N times of rotor operational speed is a dominant component to determine the helicopter vibration. Also we can predict the airframe vibration by calculating the airload of rotating blade exactly. We expect to establish the design procedure of rotor dynamics by describing the two major analysis methods necessary to rotor design.