• 대한기계학회논문집B
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• 제27권12호
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• pp.1699-1707
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• 2003

Coriolis mass flowmeter(CMF), which can measure the mass flow directly, is getting rapid attention for the industrial and custody transfer purpose. In order to study the characteristics and the applicability of CMF, it is tested with the national flow standard system. Two types of sensing tube, U-type and straight type, are employed in the test. Water, spindle oil and viscosity Standard Reference Material whose viscosities are 1, 20 and, 67 $\textrm{mm}^2$/s, respectively, are studied. It is shown that the linearity of CMF is getting deteriorated as the fluid viscosity increases, which is due to the zero drift and the relaxation time of the fluid. To test its applicability in the case of high pressured gas, it is calibrated using compressed air, It shows 1∼l.6 % deviations compared to the calibration results using water. It concludes that the fluid velocity in CMF should be lower than the sonic velocity. In addition, the effects of the vibration from the pipeline and pump on CMF as well as the long term stability are studied.

• 한국입자에어로졸학회지
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• 제8권1호
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• pp.29-35
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• 2012

The Faraday cup electrode of different size has been developed and evaluated to investigate the diffusion effect of particles by Brownian motion in a particle beam mass spectrometer(PBMS). Particles which focused and accelerated by aerodynamic lens are charged to saturation in an electron beam, and then deflected electrostatically into a Faraday cup detector for measurement of the particle current. The concentration of particles is converted from currents detected by Faraday cup. Measurements of particle current as a function of deflection voltage are combined with measured relationships between particle velocity and diameter, charge and diameter, and mass and diameter, to determine the particle size distribution. The particle currents were measured using 5, 10, 20, 40 mm sized Faraday cup that can be move to one direction by motion shaft. The current difference for each sizes as a function of position was compared to figure out diffusion effect during transport. Polystyrene latex(PSL) 100, 200 nm sized standard particles were used for evaluation. The measurement using 5 mm sized Faraday cup has the highest resolution in a diffusion distance and the smaller particles had widely diffused.

• 동력기계공학회지
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• 제11권4호
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• pp.103-108
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• 2007

In general, the swing motion of the crane is controlled and suppressed by activating the trolley motion. In many papers reported by us, we suggested a new type of anti-sway control system of the crane. In the proposed control system, a small auxiliary mass(moving-mass) is installed on the spreader and the swing motion is controlled by moving the auxiliary mass. The actuator reaction against the auxiliary mass applies inertial control forces to the container in order to reduce the swing motion in the desired manner. The measuring system is based on laser sensor or others. However it is not so useful in real world. Especially, in this paper, the image sensor is used to measures the motions of the spreader and the measured data are fed back to the controller in real time. The applied image processing technique is a kind of robust template matching method which is named Vector Code Correlation (VCC) and devised to consider the real environmental conditions. And the $H_{\infty}$ based control technique is applied to suppress swing motion of the crane. And the experimental result shows that the proposed measurement system based on image sensor and control system is useful and robust to disturbances.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.447-447
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• 2011

We studied to detect the mass variation using micro mechanical resonator. For measuring the resonance frequency of the micro mechanical system, optical method using laser interference is selected. A simple resonator is prepared by attaching an AFM cantilever on the piezo stack. The piezo stack makes a the cantilever vibrated with its resonance frequency. To change the mass of the resonator, gold was evaporated on the cantilever. We measured how much resonance frequency was changed according to the amount of gold attached on cantilever. This resonator is able to perform the role of a mass sensor and has a resolution of the order of micrograms. The fabrication of the resonator and measurement setup for detecting the mechanical resonance will be introduced in this presentation.

• 대한기계학회논문집
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• 제17권10호
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• pp.2624-2633
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• 1993

Mass transfer experiment by naphthalene sublimation method has great advantages in measurement of local transfer coefficients in the region of a three dimensional flow or for a model of complex geometry, which is considered to be very difficult with conventional heat transfer measurements. Mass transfer data obtained by naphthalene sublimation technique are converted to the heat transfer data through heat/mass transfer analogy. This analogy is valid for a simple or laminar flow, but new insight is needed when applying to a turbulent flow or complex flow such as separation, reattachment and recirculation, The purpose of this research is to investigate how geometries and flow conditions incorporate heat/mass transfer analogy. Mass transfer experiments are performed using naphthalene sublimation technique for a flat plate, a circular cylinder, and rectangular cylinders. And mass transfer data are compared with earlier heat transfer measurements for the same geometries. Usefulness of analogy relation between heat and mass transfer is examined with these results.

• Mass Spectrometry Letters
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• 제2권1호
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• pp.1-7
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• 2011

China's rapid economic growth has resulted in significant environmental side effects. Therefore, China has been interested in reducing her dependence on foreign oil and gas by developing technologies needed for hydrogen, in addition to her increasing energy mix of nuclear and renewable energy form, such as solar and wind power. There are three isotopes of hydrogen, i.e. protium (P or H), deuterium (D), and tritium (T). Both deuterium and tritium are important materials in nuclear fuel cycle industry. Tritium is one of the critical radioactive nuclides. Planning for and implementing contamination control as a part of normal operation and maintenance activities is an important function in any hydrogen facility, especially tritium facility. The development of hydrogen isotopes analysis is the key issues in this area. Mass spectrometry (MS) with medium (about 600) and high resolution (> 1,400) is commercially available; however, the routine analysis of hydrogen isotopes is done with low-resolution MS (< 200) in China. This paper summarizes the progress of MS measurement technology for hydrogen isotope abundance in China, focusing on our lab's research program and technical status. An analyzing method has been introduced for accurate measurement of tritium abundance in the H.D.T system by low resolution MAT-253 MS. The quotient of compression ratio coefficient is determined by building up equipment for laboratory-scale preparation of secondary standard gases and by considering the difference in sensitivity between hydrogen isotopes. The results show that the measured value is reproducible within the relative error range of 0.8% for gas samples of different tritium abundance.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.118-122
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• 1999

Thermal mass flow meter was developed using principle of convective heat transfer. The advantage of thermal mass flow meter is measuring mass flow directly, therefore, it is not required to use densitometer or temperature/pressure and DP gages. The final accuracy of this thermal mass flow meter is $\pm1.0{\%}$ or better, reproducibility is $\pm0.2{\%}$, and the response time is 600 ms. The thermal mass flow meter was developed from a single point to multi-points (maximum is 9 points), and the number of points is determined according to desired accuracy and size of piping/duct. Since this thermal mass flow meter adopted microprocessor based design, it is intrinsically accurate, self-error detectable, and has self-diagnosis function. The applications of this thermal mass flow meter are for measurement and control of HVAC air flow, other gas flow, and liquid flow.

• Asian Journal of Atmospheric Environment
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• 제10권1호
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• pp.1-12
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• 2016

Numerous researchers have proposed that surface area is a more appropriate indicator than mass for evaluating pulmonary inflammatory responses caused by exposure to fine and ultrafine particles. In this study, measurements of surface area concentrations of aerosols were conducted in Yokohama, Japan, using the diffusion charging method. $PM_{2.5}$ mass concentration and black carbon concentration in $PM_{2.5}$ were also measured. The 24-hour continuous measurement campaigns were conducted 39 times from March to November, 2014. The surface area concentration was more closely correlated with the black carbon concentration than with the $PM_{2.5}$ mass concentration. It is considered that the abundance of black carbon particles significantly affects the surface area concentration of $PM_{2.5}$. The strength of the correlation between the surface area and black carbon concentrations varied considerably among the measurement campaigns. A relatively weaker afternoon correlation was observed compared with the other time zones (morning, evening, and night). We consider that these phenomena are due to the transportation/formation of the particles other than black carbon that affects surface area concentration and/or the variation of the surface condition of the black carbon particles.

• 한국생산제조학회지
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• 제20권5호
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• pp.623-631
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• 2011

Light emitting diodes (LEDs) which can produce uniform luminescence need a very difficult and complex procedure because LEDs have strong and straight optical property. One of the major parameters for LED production is the determination of the viewing angle. However, in the present, there is still no available production technology to measure LED viewing angle and optical property. In this study, we developed a five-side LED viewing angle and optical property measurement system, having a source meter that uses a high speed switching photo relay instead of a mercury relay. This new measurement system can measure the viewing angle at a very high accuracy of ${\pm}0.66^{\circ}$. This new technology presents a great potential for fast and reliable LED mass production, which can significantly cut down the cost from savings in production time.

• 대한조선학회논문집
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• 제45권1호
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• pp.73-80
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• 2008

An improved method to measure the dynamic viscoelastic properties of elastomers is proposed. The method is based on the analysis of forced oscillation of a cylindrical sample loaded with inertial mass. No special equipment or instrumentation other than the ordinary vibration measurement apparatus is required. Typical measurement of the viscoelastic properties of a silicone rubber $Silastic^{(R)}$ S2 were measured over the wide frequency range from 10 Hz to 3 kHz under the action of wide region of deformation from $10^{-4}%$ to 5%. It was shown that modulus of elasticity and loss tangent fall on the single curves when the ratio of load mass to sample mass changed from 1 to 20.