• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.3
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• pp.389-396
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• 1986

A pulsed ultrasonic doppler flowmeter for mesurements of velocity profils in man is described. The device projects a beam of ultrasound in burst of 570 ns duration at 3.5 MHz. The back-scattered signals are processed to produce a signal oxrresponding to the mean velocity over a small region of the flowing stream. The observation range of 112mm is divided into 128 depth channels. The size of this sample volume determines the flowmeter sensitivity and accuracy. The device uses a quadrature detector to detect the direction of the moving target(hemoglobin). The main feature of the novel instrumnet is its simple hardware structure due to sequential signal processing.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1037-1042
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• 1990

The air-fuel ratio of an internal combustion engine must be controlled with accuracy for the improvements of exhaust emission and fuel consumption. Therefore, it is necessary to measure the exact instantaneous amounts of fuel and suction air, so we carried out the experiments for measuring the air flow velocity in a suction pipe of an internal combustion engine using three types of instantaneous air flowmeter. The results obtained can be summarized as follows: (1) The laminar-flow type flowmeter is able to measure both the average and the instantaneous flow rate, but it is necessary to rectify the pulsating air flow in the suction pipe. (2) The a spark-discharge type flow velocity meter is able to measure the instantaneous air velocity, but it is necessary to choose the suitable electrode form and the spark character. (3) The tandem-type hot-wire flow velocity meter indicates the instantaneous flow velocity and its flow direction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.4
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• pp.561-571
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• 2001

The standard uncertainty of flowrate measurement is obtained by combining that of independent variables. Gravimetric and volumetric method were applied to determine the flowrate and the standard uncertainties of flowrate measurement by both methods were evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainties of determining the flowrate were estimated from the sensitivity coefficient and the standard uncertainty of independent variables. For practical application, the methods for evaluating and expressing uncertainty in flow measurement were discussed. It was found that the uncertainties of the weighing and time measurement in gravimetric method, the volume and time measurement in volumetric method have dominant influence on that of flowrate measurement. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of flowrate measurement is shown clearly.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.601-606
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• 2005

This research presents a modeling and a manufacturing method of screw flow meter. This paper introduces the efficient design and manufacturing method of screw type flow meter using reverse engineering and test technology. The methods introduced this paper utilize the reverse engineering that is increasing accuracy of modeling and manufacturing of reverse model. And then it can be used in performance test with hydraulic test equipment. Hence this can be used in the basic document for development of the quite accurate flowmeter.

• The Korean Journal of Pain
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• v.8 no.1
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• pp.55-59
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• 1995

Stellate ganglion block (SGB) is applicated frequently to increase the blood flow and to reduce the pain in head, neck and upper extremity. The effects of SGB are able to be estimated by clinical signs and symptoms of Horner's syndrome, skin warmth, anhydrosis, etc. The effects are also estimated by sympathetic function and the blood flow. Blood flow velocities and pulsatility indices of common carotid,d axillary, brachial and radial artery were measured by Doppler flowmeter after SGB with 1% lidocaine at C6 level. Blood velocities of all arteries were increased and pulsatility indices of all arteries were decreased. This results suggest that SGB increase the blood flow of head and upper extremity and Doppler flowmeter is a good indicator of the effects of SGB.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.133-138
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• 1999

In this pager, the authors have implemented a blood flow simulator and a LDF(laser Doppler flowmeter) probe using self-mixing effect of the laser diode. The purpose of the blood flow simulator is to simulate microvascular blood flow in tissue. It consists of melinex film (thickness = $123\;{\mu}m$) which has similar optical characteristics to epidermis and porous polyethylene filter (Vyon, porosity 35%, mean pore size $50\;{\mu}m$, thickness=1 mm) which has similar optical characteristics to dermis. The blood flowmeter probe consists of laser diode(5 mW, 780 nm wavelength), CD lens(focal length 12 mm). current-to-voltage converter, highpass filter, and premplifier. It doesn't need optical fiber, therefore, implementation of the probe is simpler than conventional probe using optical fiber.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.109-113
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• 1999

Thermal mass flow meter (TMF) is used measuring the small mass flow rate of gases. Generally, flow rate measuring accuracy of TMF is $\pm2{\%}$ of full scale. TMF is manufactured for specified working pressure and specified working gas by customer. If it were applied for different working pressure and gases, flow rate measurement accuracy decreased dramatically. In this study, a TMF tested with three different gases and pressure range of 0.2 MPa to 1.0 MPa. Effect of specific heat cause to increase flow measurement error as much as ratio of specific heat compare with reference gas. Pressure change cause to increase flowrate measurement deviation about $-0.2{\%}$ as the working pressure decreased 0.1 MPa.

• 한국가시화정보학회:학술대회논문집
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• 2006.12a
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• pp.73-77
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• 2006

Flow rate measurement is one of the difficult problems in the industrial applications. Especially, flow rate in a partially filled pipeline is affected by many parameters such as water level, channel slop, etc. In the present study, prior to the development of a flowmeter, the flow characteristics has been investigated by particle image velocimetry (PIV) measurements. Three-dimensional velocity distributions were obtained from sectional measurements of velocity profiles according to the water level. As a result, it is found that there is no similarity in the velocity profile when the lateral position is changed. In addition, the maximum velocity does not always occur on the free surface. It depends on the water level. In the aspect of flow rate measurement, the previous calculus based upon point measurement techniques is proved to be inaccurate because of the lack of whole flow information.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.123.2-123
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• 2001

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.466-467
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• 2009