• The Journal of the Acoustical Society of Korea
• /
• v.25 no.1E
• /
• pp.25-31
• /
• 2006

Two twin microphones may produce particular patterns of binaural directivity by time delays between the twin microphones. The boundary element method (BEM) was used for the simulation of the sound pressure field around the KEMAR head model in order to quantify the acoustic head effect. The sound pressure onto the microphone was calculated by the BEM to an incident sound pressure. Then a planar directivity pattern was formed by four sound pressure signals from four microphones. The optimal binaural directivity pattern may be achieved by adjusting time delays at each frequency while maintaining the forward beam pattern is relatively bigger than the backward beam pattern. The simulation results were verified by the experimental measurement.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.5 no.2
• /
• pp.14-19
• /
• 2008

Hydraulic excavator consists of booms, arms, bucket, and cylinder. The cylinder make these structures moved and the cushion parts of cylinder in operation absorb the great impact which is stemmed from high velocity and pressure at cushion parts of cylinders. The cushion technology of cylinders has a great effect on the operator's comfortable as well as protecting equipment from damage by suppressing the inertia of the hydraulic excavator. In this study, three hydraulic cylinders have different shapes of a cushion ring, respectively. we studied optimal cushion pattern by analyzing the change of cushion pressure and time, according to supply pressure and velocity variations.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.261-263
• /
• 1993

The effects of the magnetic field and gas pressure on the etching characteristics were investigated in the axial magnetic field enhanced RIE system. This system has many advantages compared with the conventional RIE system ; the capability of operating at low pressure, low self-bias voltage, high electron density and high etch rate in the low pressure, but also has disadvantages such as the nonconformity of plasma density which intensifies as the magnitude of magnetic field increases. To overcome this problem we made some grooved anode and tried to find the optimal pressure and B-field strength.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.2
• /
• pp.241-247
• /
• 2013

The doctor blade is equipped in a toner cartridge and is a device to maintain the uniform thickness of a toner by controlling the pressure on the developing roller. The contact pressure between the developing roller and the doctor blade is one of the significant factors for image quality and durability of toner cartridge. The purpose of this study is to develop approximation model in order to minimize the time and cost which are needed much required in making optimal design of the doctor blade. Central composite design was used for the design of experiment and response surface design was used for approximation. The data for contact pressure were acquired through finite element analysis and data of image density and toner weight were acquired through experiment. The approximation model developed in this study has presented very high fitness.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.5
• /
• pp.790-796
• /
• 2012

Chip curling occurred during cutting process for difficult-to-cut material detracts product qualities and productivity. Among of method preventing the phenomenon, high pressure injecting cutting oil is an alterative. In this study, the optimal nozzle was designed by CFD method and it was conducted to analyse on the effect of high pressure injection on chip shape generated during cutting process and wear of insert by experimental method. As the result, it could be confirmed that high pressure injection is favorable for preventing chip curling and insert from wearing.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.3E
• /
• pp.115-122
• /
• 2005

Two twin microphones may produce particular patterns of binaural directivity by time delays between twin microphones. The boundary element method (BEM) was used for the simulation of the sound pressure field around the head model in order to quantify the acoustic head effect. The sound pressure onto the microphone was calculated by the BEM to an incident sound pressure. Then a planar directivity pattern was formed by four sound pressure signals from four microphones. The optimal binaural directivity pattern may be achieved by adjusting time delays at each frequency while maintaining the forward beam pattern is relatively bigger than the backward beam pattern.

• Korean Journal of Food Science and Technology
• /
• v.34 no.5
• /
• pp.924-926
• /
• 2002

The effects of inlet air temperature and atomizing pressure on the coating efficiency were evaluated using peanuts. Broken peanut pieces were coated with dextrin and sodium caseinate solution by a fluidized bed coater. The coating efficiency was significantly influenced by inlet air temperature and atomizing pressure, with the optimal efficiency achieved at $70^{\circ}C$ and 3 bar, respectively. The coating material consisting of dextrin and sodium caseinate could be used for preventing rancidity of broken peanut.

• Journal of Advanced Marine Engineering and Technology
• /
• v.26 no.2
• /
• pp.192-199
• /
• 2002

In continuous galvanizing process, the mass of zinc deposited and its distribution are controlled by the air pressure, effective distance from the air knife nozzle to the steel strip surface and line speed. Coating defects are resulted from the unbalance of these control factors and the inaccuracy of coating equipments. This paper investigates the main cause of coating deviation and a new air knife system for control of coating thickness was developed. We investigate dynamic pressure variation by air knife types. It is found that the coating deviation is caused by the unbalance of dynamic pressure, the irregularity of strip position, and the strip vibration. Formulating a useful coating model by using present working condition, an optimal working condition is suggested. The productivity and coating quality are improved by applying the result of this research at the shop floor.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.6
• /
• pp.21-28
• /
• 2007

Injection molding process factors such as molding temperature, injection pressure, flow rate and flow velocity, must be controlled properly in filling and packing phases in the injection molding process. In this study, effects of these factors on the injection molding were investigated through the flow analysis for birefringence and refractive index for pickup lens. This paper presents the birefringence and refractive index reduced with increasing the holding pressure and also the holding pressure time. And there are interaction with birefringence and fill time in the injection process. The optimal conditions through DOE are validated by using injection molding analysis.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.147-149
• /
• 2004

Inductively coupled plasma is commonly used for electrodeless lamp due to its ease of plasma generation. Optical characteristics significantly depend on the RF power and gas pressure of the plasma. This paper describes the measurement of spectrum as a function of RF power and gas pressure with a goal of finding optimal operating conditions of the electrodeless lamp. The gas pressure was varied from 10 [mTorr] to 100 [mTorr] and the RF power was varied from 10 [W] to 120 [W]. It was found that the intensity of wavelength tends to be decreased when argon pressure is increased, and the intensity of wavelength is increased as RF power is increased.