• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.530-533
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• 1998

In this paper, a new scheme of a boosted voltage generator (BVG) is designed for low powr DRAM's. The designed BVG can supply stable $V_{pp}$ using a new circuit operting method. This method controls charge pumping capability by switching the supply voltage and ring oscillator frequency of driving circuit, so the BVG can save area and reduce the powr dissipation during $V_{pp}$ maintaining period. The charge pumping circuit of the BVG suffers no $V_{T}$ loss and is to be applicable to low-voltage DRAM's. $V_{pp}$ level detecting circuit can detect constant value of $V_{pp}$ against temperature variation. The level of $V_{pp}$ varies -0.55%~0.098% during its maintaining period. Charge pumping circuit can make $V_{pp}$ level up to 2.95V with $V_{cc}$ =1.5V. The degecting level of $V_{pp}$ level detecting circuit changes -0.34% ~ 0.01% as temperature varies from -20 to 80.deg. C. The powr dissipation during V.$_{pp}$ maintaining period is 4.1mW.W.1mW.

• 한국항공우주학회지
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• 제43권9호
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• pp.838-844
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• 2015

본 논문은 고체 로켓 모터 연소실 내의 연소과정 중 발생하는 연소 불안정 현상을 억제하는 여러 요소들 중 입자에 의한 감쇠와 유동방향 변환 감쇠에 대한 선행연구의 연구결과를 정리 분석하였다. 입자에 의한 감쇠는 연소실 내에서 발생하는 고주파 연소불안정을 억제하는데 있어 가장 효과적이며 입자의 직경과 질량 분율에 영향을 받는다. 한편 입자에 의한 감쇠에 비해 적은 감쇠량을 갖는 유동방향 변환 감쇠는 추진제의 구조에 따라 변하며, 추진제 표면에서 생성된 와도를 고려한다면 펌핑에 의한 증폭을 고려해야한다. 그러나 추진제의 형상이 원통형일 경우 유동방향 변환 감쇠와 펌핑에 의한 증폭의 크기는 같아지고 상쇄가 일어나 연소 안정성을 보다 쉽게 평가할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1899-1903
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• 1991

This paper presents a water level control method using Z-80 microcomputer. The process considered in this paper is one tank system which is described by an unknown nonlinear differential equation. The water level is measured by the end of bar installed at a float passing through 8 pair of photointerrupters located at equal distance. Therefore, the input data to 8255 which is interface between Z-80 and photointerrupters is discrete value, namely, value under 1. values from 1 to 8, and value upper 8. The water is pumped into the tank from a reservoir by switching on a relay connected to a moter and pump driving system. The pumping is stopped by switching off the relay. Experimental studies for two types of controllers are performed in order to investigate the control performance of water level of the water pumping system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권4호
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• pp.257-263
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• 2006

New charge pump circuits with low area and high power efficiency are proposed and verified in this paper. These pump circuits do not suffer the voltage stress higher than $V_{DD}$ across their pumping capacitors. Thus they can use the thin-oxide MOSFETs as the pumping capacitors. Using the thin-oxide capacitors can reduce the area of charge pumps greatly while keeping their driving capability. Comparing the new pump (NCP-2) with the conventional pump circuit using the thick-oxide capacitors shows that the power efficiency of NCP-2 is the same with the conventional one but the area efficiency of NCP-2 is improved as much as 71.8% over the conventional one, when the $V_{PP}/V_{DD}$ ratio is 3.5 and $V_{DD}$=1.8V.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 2부
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• pp.525-528
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• 2011

Noise emitted by driving cars affects our daily life, penetrating wherever man lives or works. There are three types of possible sound emitting processes that are aerodynamic sources, air pumping and tire vibration. In this paper, a theoretical model has been studied to describe the sound radiation by the surface vibration of running tires and experimental verification has been conducted to evaluate sound radiation characteristic due to tire vibration.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.346-350
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• 1996

This paper presents a Neural Network Identification (NNI) method for modeling of highly complicated nonlinear and time varing human system with a pneumatically driven mock circulation system of Left Ventricular Assist Device(LVD). This system consists of electronic circuits and pneumatic driving circuits. The initation of systole and the pumping duration can be determined by the computer program. The line pressure from a pressure transducer inserted in the pneumatic line was recorded. System modeling is completed using the adaptively trained backpropagation learning algorithms with input variables, Heart Rate(HR), Systole-Diastole Rate(SDR), which can vary state of system, and preload, afterload, which indicate the systemic dynamic characteristics and output parameters are preload, afterload.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.291-295
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• 2004

New valve driving system to control for the best volumetric efficiency at each load of an internal combustion engine within one engine cycle has been developed. The system needs to reduce pumping loss that cause by throttle valve during the intake valve is opened. In this system the intake valve is driven by a linear DC electromagnetic actuator which is controlled by personal computer. The result is compared both installed and uninstalled actuator into the cylinder head. By both of experimental and numerical calculation, the responsibility of the valve driving system to the engine speed was examined

• Applied Science and Convergence Technology
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• 제26권6호
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• pp.189-194
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• 2017

Effects of gas injection scheme and rf driving current configuration in a dual turn inductively coupled plasma (ICP) system were analyzed by 3D numerical simulation using CFD-ACE+. Injected gases from a tunable gas nozzle system (TGN) having 12 horizontal and 12 vertical nozzles showed different paths to the pumping surface. The maximum velocity from the nozzle reached Mach 2.2 with 2.2 Pa of Ar. More than half of the injected gases from the right side of the TGN were found to go to the pump without touching the wafer surface by massless particle tracing method. Gases from the vertical nozzle with 45 degree slanted angle soared up to the hottest region beneath the ceramic lid between the inner and the outer rf turn of the antenna. Under reversed driving current configuration, the highest rf power absorption region were separated into the two inner islands and the four peaked donut region.

• 동력기계공학회지
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• 제4권3호
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• pp.34-39
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• 2000

Performance data in the literature on air lift pumps have been based primarily on pumps of long length and large diameter (high lift pumps). Since mariculture operations involve pumps of relatively short length and small diameter, performance data are required for efficient operation. To provide such data, an experimental apparatus was designed and fabricated to test all lift pumps from 2.1 to 3.4 cm inside diameter and from 40 to 300 cm in length. Instrumentation was provided to measure water flow rate and air flow rate as well as water temperature, air temperature, and pressure throughout the system. Results from this study correlate well with high lift pump data in that, for a given pump geometry, maximum water flow occurs for a specific air flow rate. Driving the pump with air flows larger or smaller than this optimum flow rate will decrease the pumping rate. The optimum flows are significantly different for low lift pumps compared to high lift pumps. However, the pumping rate for low lift pumps approaches that for high lift pumps with increasing length.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.105-106
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• 2008

As a carrier of malaria and sneak of blood, mosquitoes are an unpleasant insect. However, there are several unknown natural secretes related with mosquitoes. Among them, we focused on the blood sucking process of a female mosquito. The main objective of this study is to understand the mosquito's blood sucking mechanism that can be used to resolve the problem encountered in the injection or transport of infinitesimal biological fluids in a micro-chip. At first, the velocity fields of blood-sucking flow in a proboscis were measured using a micro-particle image velocimetry (PIV) technique. The velocity signals of flow in the proboscis show periodic variation. This seems to be resulted from the beating of the pharyngeal pump which works as driving power. To analyze the pumping mechanism, the temporal variation of the pharyngeal pump was visualized using the synchrotron X-ray micro-imaging technique. The volume variation was estimated by the help of digital image processing techniques. Once the main mechanism of blood sucking process was found, a effective micro-pumping system with high efficiency would be developed in near future.