• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.403-410
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• 2021

There are positive effects, such as pain reduction, when rheumatism patients exercise in water, but the cause of the pain reduction is unclear, and research on this is inadequate. This study examined the flow of the surface of the foot and the principles of pain relief. Unsteady simulations were conducted to analyze the flow, which was performed by repeatedly setting the movement of the foot raising and descending three times. Pressure fluctuations and frequencies were analyzed by designating pressure points at the painful location. The results showed that a positive and negative pressure of approximately ±500Pa was applied overall. A pressure of approximately ±2000Pa was applied when the direction of movement was changed. A frequency of approximately 35 to 80Hz was generated in the area where rheumatoid arthritis pain frequently occurs. The effects of reducing pain could be predicted when continuous pressure fluctuations and frequencies are applied repeatedly to the painful location, blood circulation promotion. The results could be used as basic data to understand the principles of aquatic exercise and support the development of underwater exercise programs and developing related medical equipment.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.347-357
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• 2009

The purpose of this study was to compare EMG and GRF during a free throw. Seven pairs of surface electrodes were attached to the right-hand side of the body to monitor the flexor carpi radialis (FC), extensor carpi radialis longus (EC), biceps brachii (BB), triceps brachii (TB), rectus femoris (RF), tibialis anterior (TA) and medial gastrocnemius (GM). GRF data from two force platform were collected during a free throw. The results showed that the muscle activities in the unskilled group must be highly activated prior to the moment of release. This means that a skilled participant can shoot a free throw more efficiently while producing less muscle activeness than an unskilled participant. The DCP of unskilled group in the medio-lateral direction were greater than the corresponding values in skilled group. This showed that the unskilled group were not able to shoot the free throws stably. Thus, when a teacher or instructor teaches students how to shoot free throw, it is considered that the teacher show the learner how to use not only the upper limbs but also lower limbs on the basis of the efficent connecting movement and the flexibility in a stable procedure.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.403-412
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• 2001

The Present study analyzed the pressure-flow characteristics of a Korean shunt valve. Changes in the characteristic currie depending on the design parameters were also investigated. The Korean shunt valve used in the present study was constant pressure type and our analyses were validated through experiments. We applied fluid-structure interaction to solve the flow dynamic Problem because the small diaphragm in the valve was made from flexible silicone elastomers. Considering the material nonlinearity of the hyper-elastic material. the Mooney-Rivlin approximation was employed. The results of the numerical analyses were close to the experimental results The major Pressure drop was observed to happen in the small diaphragm. The slope of the pressure-flow characteristic curve was computed to be 0.37mm$H_2O$.hr/cc, which was similar to the average value of commercial shunt valves. 0.40mm$H_2O$.hr/cc. Therefore. our valves analyzed in the Present study showed a Proper Pressure control characteristics of the constant pressure type shunt valves. The opening pressure could be controlled by adjusting the amount of predeflection of the valve diaphragm. In order to obtain opening pressures of 25mm$H_2O$ and 80mm$H_2O$, respectively, and the required predeflection was found to be 10.2$\mu$m and 35.3$\mu$m. The flow orifice size was found to be within 10$\mu$m during valve operation Therefore, Precision design and manufacturing techniques are necessary for successful operations of the shunt valve. The study indicated the amount of predeflection as well as the magnitude of corner rounding of the diaphragm edge are important design parameters to influence the slope of the pressure-flow characteristic curve.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1810-1814
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• 2006

In this paper, the brightmess from inside gas pressure, applied voltages, and operation frequency conditions was measured and the discharge characteristics in FFL(Flat Fluorescent Lamp) also were measured and discussed. The brightness and lifetime after vacuum exhaust ($350^{\circ}C$ and 1 hour) ate remarkably developed. When the gas pressure of lamp-inside is high, the brightness is also increased automatically. But for the stabilization of operation and driving voltage, the highest values of brightness at about 1000[V], 300[Torr] and 64(kHz) are measured and the results are shown as the optimized driving conditions for FFL.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.134-139
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• 2003

오늘날 산업용 차량은 대부분 유압식 클러치를 채택하여 사용하고 있다 유압식 클러치는 운전자가 손쉽게 엔진으로부터 동력을 바퀴까지 전달 또는 차단하는 기능을 갖고 있기 때문이다. 차량속도에 대한 운전자의 다양한 요구는 다수의 변속 단수를 갖는 기어트레인이나 연속가변식 변속기(CVT) 원하고 있다. 그 중에 기어단을 단속하는 클러치는 엔진의 회전력과 차량 관성력을 효과적으로 연결 또는 차단을 위해 다수의 마찰판과 유체압력을 이용하여 작동된다. 유압식 클러치는 동작방식에 따라서 유체압력이 작동하면 동력을 전달하는 POSITIVE방식과 자체 탄성 스프링력에 의해서 동력을 전달하는 NEGATIVE방식이 있다. POSITIVE방식 유압식 클러치는 동력전달시 어큐뮬레이터를 이용하여 충격을 줄이고, 부하 변동시 승차감각을 향상할 수 있는 장점이 있다 TRX500 트랙터에 사용되는 유압식 클러치는 POSITIVE방식을 채택하고 있다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.132-135
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• 2005

본 연구에서는 반도체 제조 공정에 이용되는 가스의 흐름을 감지하고 제어하는 장치를 제안하였다 압력센서를 MFC(Mass Flow Controller)에 의해 제어되는 다음 단의 파이널밸브(Final Valve)와 챔버사이의 가스관에 부착시켜, 이 압력센서의 신호와 공압밸브의 동작 신호를 디지털 회로를 이용하여 실시간으로 제어하도록 하였다. 이로써 반도체 제조 공정 중에 발생할 수 있는 2차 소성물로 인한 가스의 흐름 제어와 관련된 시스템 고장을 LED를 통해 실시간으로 확인 가능하다. 또한 가스누출고장발생 시 반도체 제조 공정의 프로세스를 중단시켜 장비의 손상 및 안전사고를 예방하는 기능도 있다. 본 연구에서 개발된 모듈을 이용함으로써 가스밸브의 오동작에 의한 반도체/디스플레이 제조장비의 신뢰성 향상을 기할 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.65-70
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• 2001

This paper presents a Receiver MMIC for the CDMA terminal. The complete circuit is composed of Low Noise Amplifier, Down Conversion Mixer, Intermediate Frequency Amplifier and Bias circuit. The Bias circuit implementation, which allows for compensation for threshold voltage and power supply voltage variation are provided. The proposed topology has high linearity and low noise characteristics. Results of the designed circuit are as follows: Overall conversion gain is 28.5 dB, input IP3 of LNA is 8 dBm, input IP3 of down conversion mixer is 0 dBm and total DC current consumption is 22.1 mA.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.269-272
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• 2001

실리콘 마이크로머시닝 기술과 바이폴라 공정으로 집적화된 압력센서를 제작하고 동작특성 평가를 수행하였다. 센서부 보상파라미터를 추출하였고 트리밍 공정을 통하여 출력전압의 보상을 수행하였다. 센서 특성은 압저항 위치, 마스크 정렬 오차, 다이어프램 정밀두께제어 정도, 보호막의 과도식각 정도 등에 의하여 민감하게 좌우됨을 알 수 있었다. 웨이퍼별 샘플추출을 통하여 센서부 감도는 평균 0.653mV/kPa, 감도의 온도계수는 -2078.8ppm/℃, 옵셋 전압은 30.78mV, 옵셋전압의 온도계수는 32.11㎶/℃로 측정되었다. 추출된 샘플의 다이어프램 두께오차는 27±2.5㎛였다. 센서부 특성평가 결과를 통하여 신호처리회로의 옵셋 및 스팬보상, 온도보상을 위한 트리밍 공정을 수행한 결과 개발사양을 만족하는 결과를 얻을 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.5
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• pp.373-377
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• 2005

In this paper the gas leakage controller in processing chamber for semiconductor manufacturing is proposed. A pressure sensor is connected between the final valve and the numeric valve. A pressure sensor signal and a numeric valve signal are controlled by a proposed digital circuit module. Gas leakage condition, producing by 2nd plasticity in semiconductor process, display at LED. The proposed controller module is useful for monitoring the gas flow for preventing the critical process gas leakage.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.171-172
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• 2007

PDP의 luminous efficacy의 향상을 위해서는 동작가스의 연구가 매우 중요하다. 본 논문에서는 bolsig simulator를 사용하여 여러 비율의 Xe+Kr+Ne 3원가스 시뮬레이션을 통하여 각 가스입자들에 전달되는 이온화에너지, 여기에너지를 조사하였다. 실험에서 short discharge gap과 long discharge gap을 가진 7인치 테스트 패널 2개를 사용하여 가스압력과 Xe+Kr+Ne 혼합비를 변화시켜가며 discharge voltage, luminance, luminous efficacy를 측정하여, 방전특성을 연구하였다.