• 음성과학
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• 제5권2호
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• pp.77-91
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• 1999

The purpose of this paper is to investigate the phonetic characteristics of the 'focus' phrases associated with the particle '-man' in Korean. The particle '-man' is a bound morpheme which, like other postpositions such as the subject marker '-ka' and the object marker '-lil', the so-called 'case markers' in Korean, typically attaches to a noun (phrase). The semantics of '-man' roughly corresponds to that of only, its counterpart in English, and is thus classified as a 'delimiter' (Yang 1973). It is assumed in this paper that '-man', like only in English, should have a 'focus' associated with it (von Stechow 1991, Rooth 1992). In general, '-man' attached phrases get the focus, but sometimes the association is not clear-cut, especially in the cases of emphatic use of '-man' or when the context strongly favors other phrase as the focus (Choe 1996). In this paper, we compare the phonetic characteristics of the '-man' marked phrases with those to which '-ka'/'-lil' is attached, and conclude that the focused '-man' phrases show higher fundamental frequencies than their equally focused 'case' -marked counterparts. However, when the context clearly forces the focus to fall on phrases other than the '-man' or '-ka'/'-lil' attached ones, there is no meaningful difference in fundamental frequency between the '-man' and '-ka'/'-lil' attached phrases. We also compare the phonetic characteristics of the regular use of '-man' with those of the emphatic '-man'. According to our experiments, the emphatic '-man' does not bring forth its phonetic effects, namely, higher fundamental frequencies, on the' -man' attached words or phrases but rather in various other ways such as higher fundamental frequencies in '-man', lengthening of the following word-initial syllable, or the inclusion of the following word in the same accentual phrase. Finally, it is claimed that '-man' associated focus phenomena, especially the emphatic use of '-man', show some typical acoustic characteristics of the other well-known focus phenomena, namely, wh-interrogatives.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E1호
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• pp.13-21
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• 2005

Atmospheric concentrations of PCBs were monitored in Ansung-city, Kyonggi province during the 2001/2002 to characterize the concentration distribution and seasonal variation of particle polychlorinated biphenyls (PCBs). Average concentration of particle bound PCB showed maximum value for penta-CBs and minimum value for octa-CBs. Seasonal contributions $(%\)$ of total particle PCBs showed the highest value in winter months and lowest value in summer month, This result indicated that concentration of total particle PCBs increased with decreasing temperature in the atmosphere. Therefore, particle PCBs were easily formed by the condensation of gas phase PCBs in winter months. The total particle PCBs exhibited an inverse correlation with temperature (p<0.01) which suggested that particle PCBs were easily formed by condensation of gaseous PCBs in winter months.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1215-1217
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• 2005

One of the important problems in recent AC-PDP technology is the image sticking. In this research, we have investigated the PDP cell with constraint deposition MgO on phosphor, the electrical and optical properties in the PDP cell were examined. Also, we have investigated the correlation with image sticking and degraded MgO protective layer, phosphor in AC-PDP. As a result, we measured the secondary electron emission coefficient ${\gamma}$, discharge characteristics and Brightness for the constraint degraded phosphor are compared with those of nondegraded phosphor.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.416-421
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• 2000

We have developed a simple model for describing the non-spherical particle growth phenomena using modified 1-dimensional sectional method. In this model, we solve simultaneously particle volume and surface area conservation sectional equations which consider particles' irregularities. From the correlation between two conserved properties of sections, we can predict the evolution of the aggregates' morphology. We compared this model with a simple monodisperse-assumed model and more rigorous two dimensional sectional model. For the comparison, we simulated silica and titania particle formation and growth in a constant temperature reactor environment. This new model shows a good agreement with the detailed two dimensional sectional model in total number concentration, primary particle size. The present model can also successfully predict particle size distribution and morphology without costing very heavy computation load and memory needed for the analysis of two dimensional aerosol dynamics.

• 대한기계학회논문집B
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• 제20권5호
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• pp.1624-1638
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• 1996

A study of thermophoretic particle deposition has been carried out for a particle laden stagnation flow considering the effect of radiative heat transfer. Energy, concentration and radiative transfer equations are all coupled and have been solved iteratively assuming that absorption and scattering coefficients were proportional to the local concentration of particles. Radiative heat transfer was shown to strongly affect the profiles of temperature and particle concentration. e. g., radiation increases the thickness of thermal boundary layer and wall temperature gradients significantly. As the wall temperature gradients increase, the particle concentration at the wall decreases due to thermophoretic particle transport. The deposition rate that is thermophoretic velocity times particle concentration at the wall decreases as the effects of radiation increases. The effects of optical thickness, conduction to radiation parameter and wall emissivity have been determined. The effects of anisotropic scattering are shown as insignificant.

• 한국유체기계학회 논문집
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• 제5권1호
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• pp.7-12
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• 2002

As the first step to investigate the fundamental mechanism of a dispersed two-phase flow, we studied the detailed interactions between bubble or particle motion and flow around it. Experiments were carried out with a rising bubble or particle in stagnant water in a vertical pipe. Particles with different densities, and/or different shapes were used for comparison with a bubble. We adopted 3D-PTV (Three-Dimensional Particle Tracking Velocimetry) for measuring the bubble or particle motions, and PIV (Particle Image Velocimetry) for measuring the water flow simultaneously (Hybrid PIV). The experimental results showed that the oblate spheroidal solid particle rose along the longer axis direction at the point that the inclination of the longer axis reached the maximum, and the inclination direction changed after moving. The bubble moved to the direction that the spheroid's projected width grew up to the largest, and the minor axis of the oblate spheroidal body of the bubble was parallel to the moving direction. The trajectory of the center of the particle/bubble which was measured with 3D-PTV, was marked on the section (x-y) of the pipe. It exhibited the pattern of the particle/bubble motion.

• 한국세라믹학회지
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• 제50권6호
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• pp.528-532
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• 2013

Well-dispersed slurries of submicron-sized alumina powders were pressure-infiltrated in 3D preforms of mullite fibers and the effects of the particle size and infiltration pressure on the particle packing characteristics were investigated. Infiltration without pressure showed that the packing density increased as the particle size decreased due to the reduction of the friction between the particles and the fibers. The infiltrated preforms contained large pores in the large voids between the fiber tows and small pores in the narrow voids between the individual fibers. Pressure infiltration resulted in a packing density of 77% regardless of the particle size or the infiltration pressure(210 ~ 620 kPa). Pressure infiltration shortened the infiltration time and eliminated the large pores in preforms infiltrated with the slurries of smaller particles. The slurry pressure-infiltration process is thus an efficient method for the packing of matrix materials in various preforms.

• 대한기계학회논문집B
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• 제24권7호
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• pp.1020-1027
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• 2000

A simple model for describing the non-spherical particle growth phenomena has been developed. In this model, we solve simultaneously particle volume and surface area conservation sectional equations that consider particles' non-sphericity. From the correlation between two conserved properties of sections, we can predict the evolution of the aggregates' morphology. This model was compared with a simple monodisperse-assumed model and more rigorous two-dimensional sectional model. For comparison, formation and growth of silica particles have been simulated in a constant temperature reactor environment. This new model showed good agreement with the detailed two-dimensional sectional model in total number concentration and primary particle size. The present model successfully predicted particle size distribution and morphology without costing very heavy computation load and memory needed for the analysis of two dimensional aerosol dynamics.

• 한국입자에어로졸학회지
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• 제6권3호
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• pp.123-129
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• 2010

As the indoor activity increases in recent years, the indoor air quality becomes more important. One of the major contaminants in office space is the copy machines and the laser based printers. These devices usually emit nano-particles and chemical species that may give some health effect. The amount of particles generated by the printers and copy machines depend on printer models, printing speed, toners, papers, humidity and so on. To evaluate the emission rate of nano-particles from Laser Printers, the mass concentration measurement method has been used (BAM, 2004). However, the mass concentration measurement method for nano-particles is tedious and time consuming. Therefore, for the development of a new nano-particle counting method, the nano-particle emission characteristics and size distributions are evaluated.

• 대한기계학회논문집B
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• 제21권3호
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• pp.380-391
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• 1997

A numerical study has been done on the evolution of particle size distribution in particle laden high temperature jet flows undergoing convection, diffusion, thermophoresis and coagulation. The dynamic behavior of these particles have been modelled by approximating the particle size distribution by a lognormal function throughout the process and the moments of the particle size distribution have been used to solve the general dynamic equation. The size distributions of spherical particles in the radial and axial direction have been obtained including the effect of buoyancy. Of particular interests are the variations of geometric mean diameter, number concentration and polydispersity. Results show that buoyancy significantly alters the size distribution in both axial and radial direction. One dimensional analysis for non-spherical particles has also been done and the results have been compared with the existing experimental data.