• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.91-94
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• 2003

We studied the effect of barrier rib height variation using ray-optics code incorporated with three-dimensional plasma simulation to analyze the effects of cell geometry for varying pressure conditions. The optimal barrier rib height decreased as the Xe partial pressure increased which resulted in due to the formation of local, strong sheath under high Xe partial pressure condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.181-183
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• 1994

This paper presented the developments and operations of control system for Inverter-controlled air pressure type water-supply systems. The developed controller that enables regular speed and variable speed. In addition, an air supplement control system was developed to establish a utility model of water supply facility system as well as a method to optimize its operation.

• 한국전산유체공학회지
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• 제4권1호
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• pp.34-40
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• 1999

Drag reduction on vehicles are the main concern for the body shape designers in order to lower the fuel consumption rate and to aid the driving stability. The drag of bluff bodies like transportation vehicles is mostly pressure drag due to the flow separation, which can be minimized by controlling the location and size of the separation bubble. In the present study, the TURBO-3D code is incorporated with optimal algorithm based on analytical approximation method to obtain an optimal afterbody shape of the MIRA Model corresponding to the lowest drag coefficient. For this purpose three mutually independent afterbody angles are chosen as design variables, while the drag coefficient is chosen as an objective function. It is demonstrated in the present study that an optimal body shape having the lowest drag coefficient which is about 6% lower than that of the original shape has been successfully obtained within number of iterations of tile optimal design loop.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제18권1호
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• pp.1-15
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• 2014

We have investigated optimal control strategies for prevention of ecstasy use. Ecstasy use has continued at raves and nightclubs in recent years and the reduction of ecstasy use has become one of the important issues in society. We apply optimal control theory to a model of the peer-driven dynamics of ecstasy use. Our goal is to minimize the ecstasy use class and the intervention cost. Optimal control is characterized in terms of the solution of optimality system, which is the state system coupled with the adjoint system and the optimality equations. The numerical simulations show the optimal prevention policies of ecstasy use in various scenarios.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.191-202
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• 1998

An electronic-hydraulic controlled line pressure system was suggested based on the mechanical controlled CVT base model. As a high level control strategy, a 3-D optimal line pressure map was obtained considering the driver's desire, driving conditions. Also, PID type low level controller was designed. Using the high level control strategy and the dynamic models of the base model CVT with electronic controlled line pressure system, performance simulations were carried out. It is seen from the simulation results that fuel economy of the electronic controlled strategy keeps the line pressure low, which results in the improved efficiency of the hydraulic system.

• 동력기계공학회지
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• 제10권1호
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• pp.83-89
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• 2006

Recently, the seriousness of high blood pressure was appeared as the most frequent disease of a the whole sickness in the world. However, the treatment of this disease is uncertain and produces an adverse reaction of a medicine therapy. Also, the patients are burdened with a fee for medical treatment. Therefore, in this paper, we studied effectively and financially to execute the treatment of high blood pressure using the Chinese medicine theorem that is recently arousing the great interest of the people. The main theories in this paper are blood vessel theory and acupuncture, respectively. Especially, the composed circuit systems are classified the blood pressure depressor part and the meridian points discrimination part, respectively. The blood pressure depressor part is composed generally of low-frequency generation circuit, charging-discharging circuit, and micro-computer circuit. Finally, this research have the advantage of discrimination parts such as regular voltage generating circuit, stimulus circuit, amplifying circuit, and alarm circuit.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.7.1-7.4
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• 2024

The document "Understanding the Relationship Between Particle Size, Performance, and Pressure" explores the impact of particle size on chromatographic performance and system pressure. The study highlights how smaller particles can improve separation efficiency by providing higher resolution and faster analysis times. However, this comes at the cost of increased backpressure, which can challenge the system's hardware and require higher operating pressures. The document discusses the balance needed between particle size, column dimensions, and system pressure to optimize performance without exceeding the pressure limits of chromatographic systems. It outlines the advantages of using superficially porous particles (SPPs) over fully porous particles (FPPs) in achieving high efficiency with lower backpressure. The study also emphasizes the importance of selecting appropriate column dimensions and flow rates to manage system pressure while maintaining optimal performance. In conclusion, understanding the interplay between particle size, performance, and pressure is crucial for optimizing chromatographic separations, ensuring system longevity, and achieving high-quality analytical results.

• Neonatal Medicine
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• 제25권1호
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• pp.1-6
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• 2018

Extremely low birth weight infants remain at increased risk of intraventricular hemorrhage from the fragile vascular bed of the germinal matrix; the roles of hypotension (ischemia) and reperfusion (hyperemia) in the development of intraventricular hemorrhage are still debated. Cerebrovascular pressure autoregulation protects the brain by maintaining constant cerebral blood flow despite changes in blood pressure. The ontogeny of cerebrovascular pressure autoregulation has not been well established and uncertainty remains about the optimal arterial blood pressure required to support brain perfusion. Another important aspect of premature cerebral hemodynamics is the critical closing pressure--the arterial blood pressure at which cerebral blood flow ceases. Interestingly, in premature infants, the critical closing pressure approximates the mean arterial blood pressure. Often in this unique population, cerebral blood flow occurs only during systole when the diastolic arterial blood pressure is equal to the critical closing pressure. Moreover, the diastolic closing margin, a metric of cerebral perfusion that normalizes diastolic arterial blood pressure to the critical closing pressure, may be a better measure than arterial blood pressure for defining cerebral perfusion in premature infants. Elevated diastolic closing margin has been associated with intraventricular hemorrhage. This review summarizes the current state of understanding of cerebral hemodynamics in premature infants.

• Journal of Advanced Marine Engineering and Technology
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• 제27권1호
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• pp.57-64
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• 2003

The characteristics of fuel spray have an important effect on engine performance such as power, specific fuel consumption and emission because fuel spray controls the mixing and combustion process in an engine. Therefore, if the characteristics of fuel spray can be measured, they can be effectively used for improving engine performance. The major factors controlling fuel spray are injection pressure, ambient pressure and engine speed. In this study, the experiment is performed in a high temperature and high pressure chamber. In experiments, spray tip penetration, spray angle and spray tip velocity are measured at various injection pressure (10 and 14 MPa), ambient pressure(3,4 and 5 MPa), fuel pump speed(500, 700 and 900 rpm). Experimental results are useful for deriving an experimental spray equation and design an optimal engine. The results showed that injection pressure, ambient pressure and fuel pump speed are important factors influencing on the characteristics of spray. 1) Injection pressure influences on the characteristics of spray. That is, as injection pressure is increased, spray angle is decreased but spray penetration and spray tip velocity is increased. 2) Spray angle and spray penetration are increased as fuel pump speed is increased.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.277-285
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• 1998

This paper presents the deformation characteristics of the moving pressure plate in a balanced type vane pump that widely used automotive power steering systems. Moving pressure plate can control the clearance between rotor and plate in accordance with load pressure variation; it always guarantees that pump to have optimal volumetric efficiency. In this paper, firstly, we calculate the acting force on the pressure plate, which is used to determine the angular position and load condition for analyzing the deformation of pressure plate. Secondary, finite element method is used for the deformation analysis. As results of acting force analysis, it is found that maximum difference of forces occurs at angular position 28$\circ$ from the small arc center of cam ring and load pressure is a dominant factor to affect acting force variation. The deformation of pressure plate increases as load pressure increases. At high load pressure, the deformation of pressure plate becomes larger than the initial clearance between rotor and plate. Therefore, it is required to design the plate for controlling the deformation.