• 한국기계가공학회지
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• 제17권5호
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• pp.70-75
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• 2018

This study analyzes the change of Al 6061-T6 specimen surface shape when undergoing microparticle spraying and analyzes the influence of factors on the experiment. Fine particle spraying is applied to the specimen and the surface shape of the processed surface is measured through a surface shape measuring device. The measured data was analyzed by the ANOVA method to investigate the effect of factors such as particle, nozzle diameter, pressure, injection height, and injection time on the injection depth and injection diameter.

• Environmental Engineering Research
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• 제20권3호
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• pp.237-245
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• 2015

Particulate matter in indoor environments has caused public concerns in recent years. The objective of this research is to explore the influence of radiators on particle size distributions and concentrations. The particle size distributions as well as concentrations above radiators and in the adjacent indoor air are monitored in forty-two indoor environments in Xi'an, China. The temperatures, relative humidity and air velocities are also measured. The particle size distributions above radiators at ten locations are analyzed. The results show that the functional difference of indoor environments has little impact on the particle size distributions above radiators. Then the effects of the environmental parameters (particle concentrations in the adjacent indoor air, temperatures, relative humidities and air velocities) on particle concentrations above radiators are assessed by applying multiple linear regression analysis. Three multiple linear regression models are established to predict the concentrations of $PM_{10}$, $PM_{2.5}$ and $PM_1$ above radiators.

• 대한기계학회논문집B
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• 제20권6호
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• pp.2005-2013
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• 1996

Particle paths and flow fields in a prototype differential mobility analyzer (DMA) were numerically analyzed solving Navier-Stokes equation, electric field equation and particle motion considering viscous drag force, Coulomb force and polarization force. Analytically predicted particle diameters for the prototype DMA are in good agreement with the measured particle diameters within $\pm$1%. And the analytically predicted particle diameters are also in good agreement with numerical results for the prototype DMA.

• 한국분말재료학회지
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• 제22권5호
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• pp.337-343
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• 2015

Powder compaction is a continually and rapidly evolving technology where it is a highly developed method of manufacturing reliable components. To understand existing mechanisms for compaction, parameter investigation is required. Experimental investigations on powder compaction process, followed by numerical modeling of compaction are presented in this paper. The experimental work explores compression characteristics of soft and hard ductile powder materials. In order to account for deformation, fracture and movement of the particles, a discrete-finite element analysis model is defined to reflect the experimental data and to enable investigations on mechanisms present at the particle level. Effects of important simulation factors and process parameters, such as particle count, time step, particle discretization, and particle size on the powder compaction procedure have been explored.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.860-863
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• 2005

The microcapsules containing fragrant oil as functional material were prepared by in-situ polymerization with prepolymer that was made from melamine-formaldehyde (MF) as wall material of microcapsules. The effects of polymerization variables, such as the nature and concentration of surfactants, stirring rate, and stirring time, on the size and distribution of the particles were investigated. Fourier transform-infrared spectroscopy (FT-IR), thermal analysis, particle size analysis, scanning electron microscopy (SEM) observation were used to investigate the characteristics of microcapsules. Through the FT-IR and SEM analysis, we found that the prepared microcapsules were containing fragrant oil and the shape of particle was spherical. The nature and concentration of surfactants, stirring rate, and stirring time had profound effects on the particle size and particle size distribution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1925-1928
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• 1996

In this work, the behavior of conducting wire type particles existing inside the cylinder type coaxial electrode has been systematically investigated by charge simulation method and electrostatic force analysis from the view point of the acquired charging before being lifted off into the gap under the high ac voltage. Spheroidal charge are adopted as a image charge for the CSM analysis in order to calculate the acquired charges of the particles which are erected on the surface of the outer electrode. For this purpose, different material of the particle and their lengths and diameters have been considered in view to calculate their lift-off field, acquired charge and to understand their effect on the lift-off voltage. The results imply that the particle lengths and diameter have an different influence on the particle behavior in GIS system.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.67-72
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• 2003

For the analysis of Kirchhoff plate bending problems, a new meshless method is implemented. For the satisfaction of the $C^1$ continuity condition in which the first derivative is treated an another primary variable, Hermite interpolation is enforced on standard reproducing kernel particle method. In order to impose essential boundary conditions on solving $C^1$ continuity problems, shape function modifications are adopted. Through numerical tests, the characteristics and accuracy of the HRKPM are investigated and compared with the finite element analysis. By this implementatioa it is shown that high accuracy is achieved by using HRKPM for solving Kirchhoff plate bending problems.

• 한국지반신소재학회논문집
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• 제12권1호
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• pp.1-10
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• 2013

본 연구는 포천에서 채취된 화강풍화토를 불산용액을 이용하여 인공적으로 풍화를 진행시켜서 풍화도 변화에 따른 화강풍화토의 입자파쇄 특성을 연구하였다. 이를 위해 조성광물 분석을 통한 풍화지수 결정 후, 입도분석, 표준다짐시험 및 변수위 투수시험을 실시하였다. 본 연구결과는 풍화가 진행되면서 전체입경분포에서 입자파쇄가 진행되었으며, 입경 $D_{10}$과 $D_{50}$에 대한 비표면적을 비교한 결과 입경 $D_{50}$ 이하의 작은 입경분포에서 입자파쇄가 활발하게 진행된 것으로 나타났다. 또한 다짐에 의한 입자파쇄 결과는 최적함수비 부근에서 입자파쇄가 최대치를 보였고 풍화가 진행됨에 따라서 비표면적 증분비가 감소하는 것으로 보아 풍화지수가 높을수록 입자파쇄에 둔감한 것으로 나타났다.

• 한국의류학회지
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• 제25권6호
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• pp.1037-1045
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• 2001

This research is done to design and manufacture prototype clean room garments to improve the product yield of the clean room processing. To assist the research, other papers and references on the same subject were collected for analysis. Also the researcher made interviews with the workers at the clean room. The prototype garments made for this project was compared against the commercially available clean room garments used in the industry. A set of test was conducted to measure particle release from the garments. The prototype clean room garments was manufactured after having considered all the aspects stated above, and tested for the level of particle release. The test subjects performed 4 different movements(marching, arms stretch, squat and rise, and jogging) while wearing the prototype garments and commercially available clean room garments. Particle counts produced by each movement were measured. The data collected was statistically analyzed. The followings are the result of the test. 1) Overall, the prototype garments yielded less particle release.(p<0.001) 2) It showed greatest difference of particle counts for jogging(p<0.001) and squat and rise(p<0.001). In the arms stretch test. the prototype garments was also more effective in controling the particle, however, in the marching test. no significant difference was detected. 3) The prototype garments had less particle release in upper(p<0.001), middle(p< 0.001), and lower level(p<0.01) than the commercially available clean room garments. Manufacturing a new fabric for the clean room processing is important, but this research proves that the design of the clean room garments also determines the efficiency garments in the particle control. Therefore the same fabric can perform differently according to how it is designed. Improving the design will also improve the 7article control and reduce the cost of research. Eventually, the manufacturers will increase the product yield.

• 한국입자에어로졸학회지
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• 제13권2호
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• pp.53-63
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• 2017

As semiconductor process was highly integrated, particle contamination became a major issue. Because particle contamination is related with process yields directly, particles with a diameter larger than half pitch of gate should be controlled. PBMS (Particle beam mass spectrometry) is one of powerful nano particle measurement device. It can measure 5~500 nm particles at ~ 100 mtorr condition in real time by in-situ method. However its usage is restricted to research filed only, due to its big device volume and high price. Therefore aperture changeable aerodynamic lenses (ACALs) which can control particle focusing characteristics by changing its aperture diameter was proposed in this study. Unlike conventional aerodynamic lenses which changes particle focusing efficiency when operating condition is changed, ACALs can maintain particle focusing efficiency. Therefore, it can be used for a multi-monitoring system that connects one PBMS and several process chambers, which greatly improves the commercialization possibility of the PBMS. ACALs was designed based on Stokes number and evaluated by numerical method. Numerical analysis results showed aperture diameter changeable aerodynamic lenses can focus 5 to 100 nm standard particles at 0.1 to 10 torr upstream pressure.