• 유공압시스템학회논문집
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• 제2권1호
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• pp.15-22
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• 2005

The purpose of this study is to find the effective dynamic characteristics of an improved pneumatic cushion cylinder with a spring type needle valve. The dynamic model represented the peak pressure control method when the pneumatic cushion cylinder is moving forward or backward in the horizontal direction. It was found from the simulation results that the peak pressure in the cushion chamber is affected by the spring, which helps to understand the performance of the pneumatic cushion cylinder and to improve or design a better cushion needle valve component. From the simulation results, the stability of pneumatic cushion cylinder with a spring type needle valve was superior and its cushion capability was also better than that without the spring.

• 오토저널
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• 제9권4호
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• pp.35-40
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• 1987

The experimental study, using constant pressure injection system, is carried out to investigate the effect of the geometrical shape changes of the needle valve of the effective flow area, the spray angle and the Sauter's Mean Diameter according to needle valve lift for a pintle-type injection nozzle. The results are as follows: 1) With the increase of the needle valve lift, the effective flow area is increased, the spray angle is at first increased and later decreased, and the Sauter's Mean Diameter is decreased. 2) It is also shown that the spray angle is maximum at the rapidly increased region of the effective flow area.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.745-752
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• 2003

Injection technology is one of the important technologies in a diesel engine. Many studies have done on the injection system. In this study, the fuel chamber geometry, the orifice ratio and the needle lift of the injection valve of a diesel engine for generating electricity are varied and tested. The injection pressure, duration and spray shapes are produced with pressure transducer, needle lift sensor and highspeed camera. The result shows that the nozzle hole size has influence on the rail pressure and injection duration sensuously.

• 한국분무공학회지
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• 제13권4호
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• pp.212-219
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• 2008

To develop the twin-fluid atomizer having the excellent performance of painting, the spray characteristics of how a wide area can be painted efficiently by one time spraying were studied in this paper. Spray phenomena are affected by the many factors determining the spray field such as the spraying pressure of gas, the spraying pressure and viscosity of liquid paints, the opening duration of needle valve, the design dimension of nozzle, and so on. As the results of experiments, these factors affecting on spray characteristics were suggested as followings; 1) The optimum spraying pressure of gas was $0.015{\sim}0.02\;kPa$, and the appropriate spraying pressure of liquid paint was 0.01kPa, In these situations, the setting up pressures must be compensated as much as the losing amount of pressure because a decompression occurred when operating valves. 2) The duration of opening the needle valve must be sustained for $1{\sim}2$ seconds to inject gas after spraying the liquid paint. This operating of the needle valve was necessary to avoid the affect on the changing of liquid column length, and to prevent the droplet deposit at the initial time of spraying. 3) The spray tip penetration was gained form the experimental equation, and the effective spraying angle was $85^{\circ}{\pm}5^{\circ}$ just at he appropriate spraying pressure of gas. The distribution of the area sprayed had the variation in $350{\pm}50\;mm$ because of the spraying pressure of gas, the its distance from the spray tip, and the lift of the needle valve.

• 한국분무공학회지
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• 제10권1호
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• pp.24-34
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• 2005

Injection technology is one of the important technologies in a diesel engine. Many studies have done on the injection system. In this study, the fuel chamber geometry, the orifice ratio and the needle lift of the injection valve for a marine diesel engine are varied, and simulated. The result shows that the nozzle hole size has influence on the rail pressure and injection duration sensitively. The decrease of the static pressure at the nozzle hole entrance and the increase of the dynamic pressure on the outlet surface are occurred with the increase of the nozzle hole diameter. The highest dynamic pressure of the outlet was occurred at the needle lift of 0.4mm and the nozzle hole diameter of 0.328mm in this test nozzle.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.24-30
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• 2013

This paper studies the comparative analysis on two different internal cushion devices (the types of needle and relief valve) used to absorb the energy which is generated when the pneumatic cylinder moves with the load at meter-out speed control system. The effect at varying the piston velocity under same driving condition is mainly investigated. The simulation results on pressure in the cushion chamber and the dynamic behavior of the relief valve type cushion device are compared with the needle valve type. Design and performance are improved with the cushion configuration of better quality at high-speed pneumatic cylinder. Based on the relation between absorbed energy and impact energy at cushion process, cushion performance at pneumatic cylinder is evaluated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.569-570
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• 2008

• 드라이브 ㆍ 컨트롤
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• 제11권4호
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• pp.61-67
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• 2014

When a manual transmission equipped car stops on an incline where the nose of the car is higher than the rear, hill-start control or hill-holder could prevent the vehicle from rolling backward as the car moves forward. The easy-hill assist valve consists of a check valve and a needle type ON/OFF solenoid valve connected in parallel; it is a hydraulic actuator that can maintain brake pressure using an electrical signal from the ECU. As the EHA valve is a safety-related component of the brake system, high reliability as well as superior dynamic performance is required for it to be applied in commercial vehicles. This paper presents the design of the EHA valve as a piece of equipment that can simulate the brake actuation pressure with a pressurizing piston. Following specific test standards, the experimental results validate the implemented functions of the test equipment, proving the test stand to be effective for the performance and endurance of the EHA valve.

• 대한의용생체공학회:의공학회지
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• 제33권4호
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• pp.202-206
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• 2012

In this study, we developed transdermal direct drug delivery device using micro-needle painlessly. We has fabricated micro-needle that is 130 ${\mu}m$ thickness and 250 ${\mu}m$length with 10 ${\mu}m$ spiral groove for rolling down drug. Head part of micro-needle device is composed of 20ea micro-needles, an on-off valve and a protective cap. Glass bottle for containing drug is connected to head part of micro-needle device. We examined the puncture characteristic testing using porcine skin and drug delivery testing using porcine, rat skin with Indian Ink.

• 오토저널
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• 제8권3호
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• pp.16-27
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• 1986

In this study, low emission gasoline engine system is developed utilizing an EGR valve, 3 way catalytic converter and electronic fuel injection system. EGR was controlled by a needle valve and optimized at the engine conditions. Throttle body fuel injection system is used for fueling. When the engine was operated at constant speed by the electronic engine control system with the 3 way catalytic converter, th emissions were reduced by 50 to 90% in volume depending on he engine operating conditions.