• Journal of Korean Academy of Fundamentals of Nursing
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• v.3 no.1
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• pp.96-107
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• 1996

Automated blood pressure monitors have gained acceptance in many clinical settings with the increasing demand, the accurate BP measuring devices reguire the need for validation. We have evaluated the Dinamap 8100, an oscillometric automated blood pressure monitor, using the Mercury sphygmomanometer as a reference. Comparison of sphygmomanometers was conducted 60 patients (30-Normotensive group, 30-Hypertensive group at Seoul National University Hospital. Two trained observers took measure blood pressure(systolic/diastolic) at the same time using the Dinamap 8100 on one arm and the Mercury on the other. For each measurement, the device was randomly selected from a group of devices repetively used for the experiment. Mean readings for systolic pressure with the Dinamap 8100 in normotensive group were lower(mean difference ; 4.26mmHg) than the Mercury type. Mean readings for systolic pressure with the Dinamap 8100 in hypertensive group were lower(mean difference ; 9.05mmHg) than the Mercury type. Mean readings for diastolic pressure with the Dinamap 8100 in normotensive group were lower (mean difference ; 7.46mmHg) than the Mercury type. Mean readings for diastolic pressure with the Dinamap 8100 in hypertensive group were lower(mean difference ; 9.03mmHg) than the Mercury type. We have found that blood pressure readings with the Dinamap 8100 were lower than those with the Mercury type. we are using the Mercury type in clinics, although it has observer bias and terminal digit preference. But the Dinamap 8100 is readily portable, simple to use, and capable of preventing observer bias and terminal digit preference. The Dinamap 8100 is acceptable for blood pressure determination in subjects who are normotensive or hypertensive ones.

• Journal of Drive and Control
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• v.11 no.4
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• pp.53-60
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• 2014

This paper proposes a control scheme to reduce the power consumption of a variable displacement swash-plate type piston pump supplying oil to a valve-controlled hydraulic cylinder at constant pressure. Whenever flow rate demand was absent, the swash plate angle and the pump speed were changed to the minimum values required to compensate for the internal leakage flow. In response to command signals, the pump speed was changed in proportion to the absolute mean value of the speed component for position commands. At the same time, a pressure regulator was activated to maintain constant system pressure by precisely adjusting the pump speed with the swash plate angle fixed at the maximum. The conventional system consisting of a pressure-compensated variable displacement type pump is driven at a constant speed of 1,800rpm. By comparison, computer simulation and experimental results showed that idling power at stand-by status could be reduced by up to 70% by reducing the pump speed from 1,800rpm to 300rpm and the swash plate angle to the minimum.

• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.51-58
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• 2013

Recently, there has been an increase in the demand for natural gas as a source of clean energy, which has increased the demand for LNG carriers. However, LNG carriers require a capital investment to obtain equipment for the regasification process, which prevents fires and explosions. Thus, on account of NIMBY, a CNG carrier is suggested that eliminates the need for regasification equipment. Meanwhile, carbon dioxide emissions are more and more regulated by international conventions such as the Kyoto Protocol. Because of this, $CO_2$ carriers have also received international attention as a methodology to transport and store $CO_2$ cargoes. Several vessels or tanks to transport and store $CO_2$ gas have been studied in various countries. This paper proposes a conceptual design for a 20ft container shaped tank to effectively transport small cargoes of $CO_2$ and CNG. The proposed pressure vessel or tank will be carried by a conventional containership or special cargo ship. The influences of the design parameters for proposed pressure vessel or tank. Including the materials, scantlings, and shape of the pressure vessel, are studied theoretically and computationally.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.64-68
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• 2016

High Temperature Superconductor power cable systems are being developed actively to solve the problem of increasing power demand. With increases in the unit length of the High Temperature Superconductor power cable, it is necessary to develop highly efficient and reliable cryogenic pumps to transport the coolant over long distances. Generally, to obtain a high degree of efficiency, the cryogenic pump requires a high pressure rise with a low flow rate, and a partial emission type pump is appropriate considering its low specific speed, which is different from the conventional centrifugal type, full emission type. This paper describes the design of a partial emission pump to circulate subcooled liquid nitrogen. It consists of an impeller, a circular case and a diffuser. The conventional pump and the partial emission pump have different features in the impeller and the discharge flow passage. The partial emission pump uses an impeller with straight radial blades. The emission of working fluid does not occur continuously from all of the impeller channels, and the diffuser allows the flow only from a part of the impeller channels. As the area of the diffuser increases gradually, it converts the dynamic pressure into static pressure while minimizing the loss of total pressure. We used the known numerical method for the optimum design process and made a CFD analysis to verify the theoretical performance.

• Journal of Aerospace System Engineering
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• v.3 no.3
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• pp.39-44
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• 2009

Humans rely on the availability of a supply of gaseous oxygen for survival. If the minimal requirements for oxygen are not met, both mental and physical abilities and performance are degraded rapidly. So oxygen systems are required for the aircraft operating at high altitude to prevent physical and psychological problems, or loss of consciousness in an aircraft pilot, flight crew, or passengers. If oxygen system and equipments are to be included in the type design of an airplane, applicant should consider applicable airworthiness requirements and operating rules. In this paper we analyze the various oxygen system requirements for the type of aircraft, oxygen system, and operating conditions.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.7
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• pp.82-88
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• 1993

This paper describes fabrication of relative type capacitive pressure sensor to be in great demand for many fields. The fabricated sensor consists of two parts` a sensing diaphragm and a pyrox glass cover. The sensor size is 4.5${\times}3.4mm$^{2})$ and 400$\mu$m thick. To improve the nonlinearity, this sensor is designed a rectangular silicon diaphragm with a center boss structure, and in order to improve the temperature characteristics of the sensor in a packaging process, the sensing element is mounted on the pyrex glass support. Some suggestions toward the design and fabrication of improved sensors have been presented. The zero pressure capacitance, Co of sensor is 26.57pF, and the change of capacitance, ${\Delta}$C is 1.55pF from 0Kgf/Cm$^{2}$ to 1Kgf/Cm$^{2}$ at room temperature. The nonlinearity of the sensor output with center boss diaphragm is 1.29%F.S., and thermal zero shift and thermal sensitivity shift is less than 1.43%F.S./$^{\circ}C$and 0.14% F.S./$^{\circ}C$, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1091-1096
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• 2004

It is necessary to consider the stability, economic environmental-friendly problems by the development of the road, supply of the automobile, environmental problem as designing the exhaust system. To reduce the noise and the vibration of the automobile. The need for stricter regulation limits emission and demand for lower fuel comsumption. According to motor vehicle company develop variable type muffler, dual muffler and active intelligence exhaust system unit. Improvement in engine performance and fuel consumption for demand information of pressure fraction and heat characteristics. To be able to determine these factor for we experiment on each case of exhaust system unit. In this study, in order to establish the optimized conditions design factors which are taking many performance as the variable valve, it shows how the standard performance and the additional element of the exhaust system effects on the engine performance.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.192-198
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• 2005

Recently, Automobile manufacturers regarding stability, economic environmental-friendly problems by the development of automobile. This reason is increasingly strict environmental regulations to lower fuel consumption and reduce emission. Designing more efficient and low emission control exhaust system results in more efficient Performance, reduced back Pressure and higher convert efficiency. Also to reduce the noise and the vibration of the automobile. According to develop variable type muffler, dual muffler and active intelligence exhaust system unit. Improvement in engine performance and fuel consumption rate, higher conversion efficiency demand information of pressure fraction and heat characteristics. To be able to determine these factor fur we experiment on each case of exhaust system unit. In this study, how back pressure is distributed in flow-through in exhaust system and how to design exhaust system flexibleness, efficiency, lower back pressure and optimal performance. This study furnish basic data for engineers, technicians.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.1-9
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• 2009

Noise reduction for hydraulic pump is strongly demanded in the market with its efficiency and durability. In order to meet this demand, it is necessary to reveal mechanism for noise and relationship between the important factors. In this paper, mathematical model for cylinder pressure which is primary reason of pulsation and sound noise were established, and examined its pressure profile by simulation. Also, the valve plate of three kind types are manufactured and tested for piston pressure, pressure pulsation, and sound power level based on the tentative standard which is officially recognized.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1154-1160
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• 2015

This paper describes the thermal characteristics of underground power cable system terminations according to the change of ambient temperature as well as operating temperature. Recently, the failure has been gradually increasing in outdoor termination during winter season because the power demand was increased by electricity heating system. The power demand and outdoor temperature is difference between day time and night time. The temperature difference has an influence on conductor extension and shrinkage due to conductor force as well as thermal mechanical characteristics. These phenomena have daily repeated during heating and cooling period of conductors. In these cases, the insulation of outdoor terminations might be degraded by the reduced interface pressure surrounding stress relief cone. Therefore, in this paper, the thermal characteristics are variously analysed by simulation considering power demand and ambient temperature condition during winter season at epoxy type termination as well as slip-on type termination