• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권9호
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• pp.408-413
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• 2005

This paper presents the basic design technology on the hybrid type GCB(gas circuit breakers) through the test results. The three type hybrid interrupters according to the arrangement of the thermal expansion chamber and the puffer cylinder(they are called 'serial type', ' parallel/exchanged type ,' and ' parallel/separated type ' respectively in this work) were designed and manufactured and then the tests of operating characteristics and interrupting were performed using a simplified synthetic test facility. The interruption capability with the type and the opening speed and the pressure rise which is required to interrupt were examined. The change of pressure rise with the number of interruption was given quantitatively and therefore the pressure rise can be predicted. Finally, it was shown that the interruption capability tends to increase with the increasing of opening speed in the puffer type; however, the hybrid type interrupter has a different interruption characteristic.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.5-8
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• 2013

The ignition of aluminum particles under high pressure and temperature conditions is studied. The laser ablation method is used to generate aluminum particles exposed to pressures ranging between 0.35 and 2.2 GPa. A continuous wave $CO_2$ laser is then used to heat surface of the aluminum target until ignition is achieved. We confirm ignition by a spectroscopic analysis of AlO vibronic band of 484 nm wavelength. The radiant temperature is measured with respect to various pressures for tracing of required heating energy for ignition. Then the ignition temperature is deduced from the radiant temperature using the thermal diffusion equation. The established ignition criteria for corresponding temperature and pressure can be used in the modeling of detonation behavior of heavily aluminized high explosives or solid propellants.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.114-121
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• 2013

High efficiency operation is required for motors of vehicle to increase fuel efficiency due to the regulation of exhaust gas. This paper presents a control method of fuel pressure to increase fuel efficiency and a sensorless control method of BLDC motor to get higher efficiency than conventional brushed DC motor. Initial rotor position of BLDC motor is detected from current value that is occurred by test voltage pulse and rotor is accelerated by defined sequence to enter sensorless operation mode. The algorithm to control flow rate of fuel pump uses PI controller that is control motor speed to maintain the target fuel pressure commanded by ECU.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.301-306
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• 2008

A pyrogen igniter was designed to satisfy the required condition of kick motor system for the space launch vehicle. We analyzed the ignition characteristics and performed the combustion tests to verify the internal ballistic performance. In the design process, the arc-image test was carried out to find the sufficient heat flux as varying the initial pressure from 10 to 700kPa. The analysis indicated that the initial pressure condition would delay ignition time within a range from 100 to 500ms. The combustion test with an inert chamber was also performed to understand the ignition characteristics with the variation of the initial pressure of free chamber volume. Finally, we confirmed that the igniter could provide the acceptable energy to ignite the propellant of kick motor at the ground test. The result of the ground tests showed that the ignition delay time was within the design range at the atmospheric pressure condition.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권1호
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• pp.40-49
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• 2003

Dynamic characteristics of water hammer arresters installed in a building water supply system have been investigated numerically by utilizing a commercial code that employs the method of characteristics. Some preliminary results with those arrester models produced in this study agree well with the previously reported. Then, the arrester models have been incorporated into a water supply pipe system of a 59 $m^2$apartment unit constructed by a leading construction company, and their dynamic characteristics have been investigated, especially on the reduction in the water hammer pressure. It is found that the setting of the arresters in the pipe system, which is recommended by the company, may not be proper for reducing the pressure down below 1,082.0 kPa (10.0 kg$g_f$/$cm^2$) when quick-closure valves in the pipe system are closed within 30 ms at the static pressure of 542.6 kPa (4.5 kg$g_f$/$cm^2$). More arresters in the system may be required to meet pressure criteria stated on the related standards and codes.

• Journal of the Optical Society of Korea
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• 제17권4호
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• pp.300-304
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• 2013

Novel breakthrough random-hole optical fibers (RHOFs) are fabricated in a draw tower facility, by tapering an optical fiber preform packed with a silica powder mixture capable of producing air holes in situ at the high temperature of tens of hundreds in degrees Celsius. Structural and propagation characteristics of the porous RHOF are explained briefly. Experimental investigations of the invented RHOF are performed for pressure sensor applications. Remarkable results are obtained for the RHOF with desirable pressure sensitivity independent of temperature, as is required for harsh conditions as in oil reservoirs.

• Neurospine
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• 제15권4호
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• pp.394-399
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• 2018

Subarachnoid pleural fistula (SPF) is an aberrant communication between the pleural cavity and subarachnoid space, resulting in uncontrolled cerebrospinal fluid drainage. The negative pressure of the pleural cavity creates a continuous suctioning effect, thereby impeding the spontaneous closure of these fistulas. Dural tears or punctures in cardiothoracic procedures, spinal operations, and trauma are known to cause such abnormal communications. Failure to recognize this entity may result in sudden neurological or respiratory complications. Hence, a high index of suspicion is required for early diagnosis and prompt management. Noninvasive positive pressure ventilation has been described to be effective in managing such fistulas, thus mitigating the high morbidity associated with exploratory surgery for primary repair. Herein, we describe the typical presentation of SPF and the clinical course, treatment, and follow-up of a patient who sustained SPF following anterior thoracic spinal surgery.

• 유공압시스템학회논문집
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• 제3권2호
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• pp.1-6
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• 2006

The pressure regulator which is used for controlling the reducing pressure in the piezoelectrically driven pneumatic valve has been studied. The pneumatic valve of this study object is 2-stage type and consists of a piezoelectric actuator, a controller, a poppet valve and a pressure regulator. Nominal flow of 50 lpm, maximum operating pressure of 0.9MPa and frequency characteristic of 10Hz and over are required in this pneumatic valve, but the pressure regulator is needed because piezoelectric actuator has no ability to control the pressure of 0.9MPa directly. In this study, bimorph type PZT actuator of $25.2mm(L){\times}7.2mm(W){\times}0.5mm(H)$ with constant of $-220{\times}10-12$ CN-1 was proposed and investigated. Maximum operating force of 0.052 N and maximum displacement of $63{\mu}m$ were gotten from the fabricated PZT actuator. From the analysis results, the orifice diameter of 0.6mm for a piezoelectric actuator was derived and then the pressure regulator which can be operated under 0.15 MPa easily was designed and manufactured. Performance and effects of design parameters were simulated by the Simulink of Matlab software, and it was confirmed that the performance characteristics of manufactured pressure regulator are superior in the common use pressure range of 0.5 MPa to 0.7 MPa. The results show that the proposed pressure regulator is suitable for the pneumatic valve with a PZT actuator.

• Journal of Korean Biological Nursing Science
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• 제16권4호
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• pp.342-348
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• 2014

Purpose: The purpose of this study was to examine the effects of pressure ulcer classification system education on hospital nurses' knowledge and visual discrimination ability of pressure ulcer classification system and incontinence-associated dermatitis. Methods: One group pre- and post-test was used. A convenience sample of 96 nurses participating in pressure ulcer classification system education, were enrolled in single institute. The education program was composed of a 50-minute lecture on pressure ulcer classification system and case-studies. The pressure ulcer classification system and incontinence-associated dermatitis knowledge test and visual discrimination tool, consisting of 21 photographs including clinical information were used. Paired t-test was performed using SPSS/WIN 18.0. Results: The overall mean difference of pressure ulcer classification system knowledge (t=4.67, p<.001) and visual discrimination ability (t=10.58, p<.001) were statistically and significantly increased after pressure ulcer classification system education. Conclusion: Overall understanding of pressure ulcer classification system and incontinence-associated dermatitis after pressure ulcer classification system education was increased, but tended to have lack of visual discrimination ability regarding stage III, suspected deep tissue injury. Differentiated continuing education based on clinical practice is needed to improve knowledge and visual discrimination ability for pressure ulcer classification system, and comparison experiment research is required to evaluate its effects.

• Journal of Acupuncture Research
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• 제37권1호
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• pp.28-34
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• 2020

This is a systematic review of the clinical use of cupping therapy. Four domestic databases and 2 foreign databases were searched. Studies that reported the cupping pressure used during cupping therapy were included in this study. The types of cupping, cupping site, pressure, and duration of cupping were the main parameters analyzed. A total of 27 studies, including 24 experimental studies were analyzed. There were 12 constant negative pressure (domestic) studies with a range between 60 mmHg and 600 mmHg. There were 5 maximum negative pressure (domestic) studies and the maximum negative pressure was 620 mmHg. Three studies used a maximum negative pressure of 600 mmHg. There were 4 constant negative pressure (foreign) studies with a range between 75 mmHg to 750 mmHg. There were 3 maximum negative pressure (foreign) studies with a maximum pressure of 420 mmHg. The studies differed with regards to the materials used and the amount of pressure applied. Many studies had limited information and therefore generalizability of the results in this review is limited. Further experimental studies are required to establish the correlation between cupping pressure and treatment effects so that cupping therapy can be standardised.