• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.302-307
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• 2007

In this paper, a flap valve micropump with an ionic polymer-metal composite (IPMC) actuator was designed, fabricated, and experimentally characterized. A multilayered IPMC based on Nafion/layered silicate and Nafion/silica nanocomposites was fabricated for the actuation section of the micropump. The IPMC diaphragm, a key element of the mircopump, was designed so that the IPMC actuator was supported by a flexible polydimethylsiloxane (PDMS) structure at its perimeter. This design feature enabled a significantly high displacement of the IPMC diaphragm. The overall size of the micropump is $20{\times}20{\times}5$ ${mm}^3$. Water flow rates of up to 760 ${\mu}l$/min and a maximum backpressure of 1.5 kPa were recorded. A significant advantage of the proposed micropump is its low driven voltage from only 1-3 V. In addition, a simple and effective design, and an ease of manufacturing are other advantages of the present micropump.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.16-21
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• 2015

The body structure of diaphragm type preaction valve was improved in order to reduce the pressure drop. The pressure drop must be kept within 20.7 kPa to pass the revised (2012. 2. 9) standard for alarm valve and preaction valve. The pressure drop test was carried out by KFI (Korea Fire Institute) standard. The pressure drop of a preaction valve was higher than that of an alarm valve. Causes for increasing the pressure drop were investigated with the fluid flow in the valve. The preaction valve had more pressure drop factors (changes in velocity and direction) compared with the alarm valve. Inner structure of the preaction valve was changed to the clapper type to remove the pressure drop factors. In 80A and 100A size of preaction valves, the pressure drop was reduced from 80.9 and 171.0 kPa to 14.4 and 14.2 kPa respectively, after the change of the structure.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.413-418
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• 2001

We developed shunt valves used to treat patients with hydrocephalus. The valves under development were constant Pressure type ventriculoperitoneal (VP) calves made of silicone elastomer. In vitro experiments showed that our valves had similar Pressure-flow control characteristics to the valved currently available in the market. Our valves also showed competent performance in the 28 days of continuous pumping tests acording to the IS07197 specifications. We artificially inducted hydrocephalus to a 10kg beagle do9. The size of the ventricles of the dog was substantially increased and the dog showed abnormal behavior. After our valve being implanted, the ventricles recovered regular size with the normal behavior observed in the dog. The flow orifice of the shunt valve diaphragm was in the older of 10$\mu$m during calve operation and hence the pressure-flow control characteristics tended to change by a small chance in the valve dimension. Therefore, precision design and manufacturing techniques were necessary for successful operations of the shunt valves .

• KSTLE International Journal
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• v.3 no.2
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• pp.101-109
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• 2002

This paper presents the fabrication and performance inspection of a peristaltic micropump by flow simulation. The valve-less micropump using the diffuser/nozzle is consists of base plate, mid plate, top plate and connection tubes fur inlet and outlet. In detail, the base plate is composed of two diffuser nozzles and three chambers, the mid plate consists of a glass diaphragm for the volumetric change of the pumping chamber. The inlet and outlet tubes are connected at the top plate and the actuator fur pressing the diaphragm is located beneath the top plate. The micropump is fabricated on the silicon wafer by DRIE (Deep Reactive ion Etching) process. The pumping performances are tested by the pneumatic test rig and compared with the simulated results fur various dimensions of diffuser nozzles. The pumping characteristics of the micropump by the volumetric change at the pumping chamber is modeled and simulated by the commercial software of FLOW-3D. The simulated results shows that reverse flow is the inherent phenomena in the diffuser nozzle type micropump, but it can be reduced at the dual pumping chamber model.

• Journal of the Semiconductor & Display Technology
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• v.7 no.3
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• pp.29-34
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• 2008

This paper describes the fabrication and characterization of a differential pressure type integrated mass-flow controller made of stainless steel for reactive and corrosive gases. The fabricated mass-flow controller is composed of a normally closed valve and differential pressure sensor. A stacked solenoid actuator mounted on a base-block is utilized for precise and rapid control of gas flow. The differential pressure flow sensor consisting of four diaphragms can detect a flow rate by deflection of diaphragm. By a feedback control from the flow sensor to the valve actuator, it is possible to keep the flow rate constant. This device shows a fast response less than 0.3 sec. Also, this device shows accuracy less than 0.1% of full scale. It is confirmed that this device is not attacked by toxic gas, so the integrated mass-flow controller can be applied to advanced semiconductor processes which need fine mass-flow control corrosive gases with fast response.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.886-891
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• 2008

This experimental investigation is concerned with the relationship between the electrical-on time of a solenoid which is located on the top of a pulse valve and air consumption of a dust collector. For the air consumption per pulse would be one of major factors affecting the operating cost of a dust collector, more attention is needed on the behaviour of a pulse valve. A pulse jet is blasted into a bag filter as the diaphragm valve opens and inflates a bag filter. This air-blast breaks up the dust layer and cleans the filter by dislodging dust cake. It is interpreted in this research that the cleaning filter is done by the impulse of a pulse jet. Hence, the magnitude and fluctuation of the dynamic pressure is measured using by a dynamic pressure sensor and the impulse is obtained by integrating dynamic pressure variation against time. Through this experimental work, conclusions are drawn implementing magnitude of averaged impulsive pressure per pulse or pressure impulse per unit volume of consumed air.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.4
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• pp.27-32
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• 2005

Liquid valve is divided into cylinder and liquid part or composed of a single body structure. It becomes a connected structure to cylinder head after inserting stainless(STS) shaft to Teflon packing. In injecting and intercepting fluid, working efficiency becomes low because of the top and bottom round trip operation the friction between Teflon packing and STS shaft fluid leakage, decline of working environment, and each part replacement. And so target value is unattainable in productivity liquid valve design, quality, and structure change are studied. In this paper, designed to solve the existing problems basically, to prevent friction of Piston by developing diaphragm linked with piston, to satisfy long life, and to provide the prevention of leakage. The objective of the study is also to prevent remains fluid at nozzle tip after dispensing fluid, and bell close with the suction function in piston retreating.

• Journal of Chest Surgery
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• v.34 no.11
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• pp.865-869
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• 2001

Operations for extensive aortic aneurysm are generally performed as staged operations with or without elephant trunk technique. However, we must consider single stage replacement in cases that are unsuitable for elephant trunk technique. We report a case of successful sing1e stage replacement of the entire thoracic aorta from the aortic valve to the level of diaphragm. The patient was a 35-year-old male who had Marfanoid features and had previously undergone replacement of the ascending aorta for aortic dissection. He recovered without neurologic complication and was discharged on 29th day after the operation. .

• Journal of Chest Surgery
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• v.18 no.1
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• pp.13-18
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• 1985

Cortriatriatum is rare congenital heart disease characterized by the presence of a fibromuscular diaphragm that subdivides the left atrium into a proximal or "accessory" and a distal or "true" left atrial chamber. A 15 year old girl with cortriatriatum underwent surgical correction at the department of Thoracic and Cardiovascular Surgery, Soonchunhyang College in November, 1984. This case was preoperatively diagnosed as a single atrium with functional tricuspid regurgitation But on operation, we found that there were transverse septum in the left atrium through large ASD, low chamber receives the pulmonary veins, and the upper chamber gives rise to the left atrial appendage and leads to the mitral valve. And the anomalous membrane has no fenestrations. We excised completely the anomalous septum, reconstructed atrial septal defect with dacron patch and performed the tricuspid annuloplasty with DeVega method. Postoperative course was uneventful during follow up, during follow up.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.523-528
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• 1999

Subaortic stenosis in a 2.9kg, 3-month-old pug dog and a 11 kg, 4-month-old Rott -weiler dog showing signs of dyspnea, tachypnea, anorexia, exercise intolerance and depression was diagnosed with electrocardiography, thoracic radiography and ultrasonographic evaluation. In electrocardiography, PR interval widening, R wave amplitude increase in lead II in case 2, ST segment depression and left axis deviation in case 1 and 2 were identified. In thoracic radiographs, enlarged left ventricle and atrium, caudal displacement of left crus of diaphragm and caudal part of cranial mediastinum widening were identified in ventrodorsal view. In lateral view, left ventricular enlargement, secondary dorsal deviation of trachea and post-stenotic dilation of aorta were seen. Also, edematous pulmonary changes were shown in peri-hilar area. In ultrasonographic examination, left ventricular dilatation, pericardial effusion and subaortic valvular ridge were seen with real time B-mode in right parasternal long axis view. Aortic valve regurgitation was identified in color-Doppler mode.