• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.332-335
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• 2011

Electro-Mechanical Ignition Safety Device(EMISD) for solid rocket motor is designed and manufactured. The EMISD utilizes a true rotary solenoid for arming mechanism and an electric squib(initiator) for generating ignition energy. In order to prove the ignition capability of the EMISD, 10-cc Closed Bomb Test(CBT) is performed, which measures the pressure built by high temperature and high pressure gas generated by operating EMISD.

• Composites Research
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• v.27 no.6
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• pp.254-259
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• 2014

In this study, a device and pressure press process that is able to substitute autoclave process is developed. This process complements disadvantages of autoclave process which are long process-time and high production cost. The developed device provides air pressure as well as the vacuum which are greatest feature of autoclave process. The device is sealed using hydraulic pressure to keep the air pressure inside the mold. The transfer of the heat is designed to be direct. The heating and pressure charging time are decreased by reducing the interior space. Tooling cost is reduced dramatically compared to autoclave process. Spring-back phenomenon is measured and compared. The temperatures of several parts of the mold during molding are measured. The fiber volume fraction of the parts molded by autoclave process and by the developed process are compared.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.209-214
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• 2011

This study suggests a Healthcare System for elderly and disabled who have mobility impairment and use a wheelchair for long time. Seating long time in a wheelchair without reducing pressure causes high risk of developing pressure sores. Pressure sores come with great deal of pain and often lead to develop complication. Not only it takes time and effort to treat pressure sores but also increases medical expenses. Therefore, we will develop a device to help to prevent pressure sores by measuring pressure distribution while seating in a wheelchair and wirelessly send information to user device to check pressure distribution in real time. The equipment to measure body pressure is composed of FSR sitting mat which is a sensor measuring part and an user terminal which is a monitoring part. The designed mat is matrix formed FSR sensor to measure pressure. The sensor send measured data to the controller which is connected to the end of the mat, and then the collected data are sent to an user terminal through a bluetooth. Developing a pressure monitoring system will help to prevent those who have mobility impairment to manage pressure sores and furthermore relieve their burden of medical expenses.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.679-684
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• 2017

Recently, the speed of high-speed railway has been rapidly increase with the development of high-speed train design and operating technology. This causes a lot of complaints related the environmental noise in residential areas near the high-speed railway. In order to operate the high-speed railway in accordance with the design speed, noise reduction technology should be developed to meet the noise characteristics of high-speed railway. And it is important to develop the prediction technology by grasping the noise radiation characteristics. In order to meet these requirements, in recent years, infra-research for 400 km/h high speed railway has been conducted. Reliable noise prediction and noise reduction techniques have been developed through this study. This paper is concerned with wind pressure safety and noise performance evaluation of the newly developed 400 km/h noise reduction device. The wind pressure safety and The noise performance of the developed device was confirmed by this paper.

• Journal of Magnetics
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• v.18 no.2
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• pp.168-172
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• 2013

We have developed a high-field and high-frequency ESR system using a commercially available magnetometer equipped with the superconducting quantum interference device (SQUID). This is magnetization detection type ESR and ESR is observed as a change of the magnetization at the resonance condition under irradiation of the electromagnetic wave. The frequency range is from 70 to 315 GHz and the maximum magnetic field is 5 T. The sensitivity is estimated to be $10^{13}$ spins/G. The advantage of this system is that the high-field ESR measurements can be made very easily and quantitatively. Moreover, this high-field ESR can be applied to the measurements under pressure by using a widely used piston-cylinder pressure cell.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.2
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• pp.93-99
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• 2019

A pressure sensor is a device that converts an applied physical pressure into an electrical signal. Such sensors have a range of applications depending on the pressure level, from low to high pressure. Sensors that use physical pressure, when compared to those operating under air pressure, are not widely applied as they are inefficient. To solve this problem, graphene oxide, which exhibits good mechanical and electrical characteristics, was used to increase the efficiency of these pressure sensors. Graphene oxide has properties that control the movement of charges within the dielectric. Exploiting these properties, we evaluated the change in electrical characteristics when pressure was applied according to the ratio and thickness of the oxidation graph added to the pressure sensor.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.1-6
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• 2014

When the fluid energy convert into kinetic energy due to water hammer, the propagation velocity of pressure wave appear. The propagation velocity of pressure wave(1050 m/s) of very fast could be damage to the pipeline system. If the occurrence of water hammer is due to down-pressure, the faster the air exhaust or supply device is needed. it is high Speed Air Valve. In this paper, Each 3.12, 3.13, 3.72, $3.74kg/cm^2$ pipeline pressure were setting, and then executed pressure rapid drop for obtaining a high Speed Air Valve Operating time and pressure change data. the result was that pipe line pressure stabilization time were each 0.98, 1, 1.22, 1.25 sec. In other words, that pressure drop experimental results pipe line pressure was equal to atmospheric pressure without negative pressure After about one second. The study result would be useful to pipe line system stability design because this data could be foresee pressure stabilization time.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.64-67
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• 2004

The present study describes an experimental work to reduce supersonic jet noise using a control wire device that is placed into the supersonic jet stream. The jet pressure ratio is varied to obtain the supersonic jets which are operated in a wide range of over-expanded to moderately under-expanded conditions. The wire device is composed of long cylinders with a very small diameter. X-type wire device is applied to control the supersonic jet noise, and its location is varied to investigate the effect of the control wire device on supersonic jet noise. A high-quality Schlieren optical system is used to visualize the flow field of supersonic jet with and without the control wire device. Acoustic measurement is performed to obtain the overall sound pressure level and noise spectra. The results obtained show that the present wire device destroys the shock-cell structures, reduces the shock strength, and consequently leading to a substantial suppression of supersonic jet noise.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.2
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• pp.61-66
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• 2020

Recently, a variety of electric anesthetics devices have been developed and used in clinical practice to reduce the fatigue of the operator during local anesthesia for dental procedures and to compensate for the disadvantages of manual anesthesia device. In this electric anesthesia injection device, the accurate and constant delivery of pressure for drug infusion is a very important performance factor. In order to evaluate the accuracy of the transfer pressure, a small pressure gauge using a load cell is often used, but since the elastic body inside the load cell may not be able to accommodate a sufficient displacement, an error may occur when evaluating pressure performance. For these reasons, in this study, we proposed and evaluated a silicon-chrome steel (Si-Cr steel) spring jig that can accommodate relatively large displacements that can be used when evaluating the performance of a pressure-controlled pressure application device using a load cell type pressure gauge. As a result of the pressure transmissibility test and repeated measurement results using a commercial dental anesthesia injection device, a more stable result was obtained when using a spring jig, and it was confirmed that the frequency of abnormally high measurement was reduced.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.367-372
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• 2005

This study primarily is concerned with a new device which has been developed following the international standards to measure the ventilation performance at elevated temperature. This device can measure duration of ventilation, performance of electricity, static pressure at elevated temperature and also it is having provision to measure reversible performances during fire hazards. Invented device is closed circuit type system which is best suited for korean industrial environment with low cost and high efficiency. International standards has been compared and performance testing has been major using BS 7346 which is tested by Warrington Fire Research Centre.