• Proceedings of the KSME Conference
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• 2001.06d
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• pp.104-109
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• 2001

The time to measure the size distribution using Condensation Nuclei Counter(CNC) and Differential Mobility Analyzer(DMA) can be shortened by classifying particles ramping the DMA voltage exponentially and continuously. In measurement, particles sampled at different time are mixed together going through sampling tube and CNC. Because the size distribution is inversed by using detector responses to sampling time intervals in this accelerated method, the mixing effects give inversion errors to the size distribution. The mixing effects can be considered by appling the transfer function with mixing effects to the data inversion. The inversion considering this effects gives birth to the size distribution shifted to the opposite direction of the size scanning.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.4
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• pp.380-391
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• 2010

Airborne in-situ measurements of aerosol/cloud number concentrations were analyzed to investigate the effects of aerosols on warm cloud formation in the Pacific Dust Experiment (PACDEX) during April and May 2007. In the air masses originating from the Asian continent, high concentrations of fine particles including black carbon (BC) were observed when compared to other regions. A strong correlation (r=0.88) between condensation nuclei (CN) having sizes ranging from 0.1 to 1.0 mm ($CN_{0.1-1.0}$) and cloud condensation nuclei (CCN) at 0.4% supersaturation ($CCN_{0.4%}$) suggests that most of the $CN_{0.1-1.0}$ can contribute to cloud formation. The possibility of a cloud droplet formation by BC particles was expected at the high water vapor mixing ratio (WVMR) and the abundance of water-soluble components at the low altitude less than 3 km.

• Atmosphere
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• v.22 no.1
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• pp.87-96
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• 2012

Aerosol number concentration ($N_{CN}$), size distribution and cloud condensation nuclei (CCN) concentration ($N_{CCN}$) were measured during 16-21 August 2008 at Daegwallyeong (DG) located in the eastern rural region of the Korean Peninsula. In the very next week (22-29 August 2008) the same aerosol properties were measured at Yeongjong Island (YJ) in the Yellow Sea. $N_{CN}$ for all 3 size cuts (above 3, 6 and 10 nm) was significantly higher at DG than YJ, but $N_{CCN}$ was significantly lower at the former and resulted in the $N_{CCN}/N_{CN}$ ratio more than twice higher at YJ ($0.94{\pm}0.09$ vs. $0.35{\pm}0.15$ at 0.53% supersaturation). The geometric mean diameter at DG, $53{\pm}15nm$, was much smaller than that at YJ, $91{\pm}6nm$, due to the particle formation events that were likely to have occurred continuously at DG. For given mean diameter, aerosols were more likely to act as CCN at YG compared to those at DG.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.579-584
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• 2001

Agglomerated and nonagglomerated SiO2 particles are synthesized in furnace by the electrohydrodynamic spraying method and the vapor feeding method for the test particle generator this study. These polydispersed particles are classified with DMA to extract equal mobility particles. Then these particles are introduced into CNC (Condensation Nuclei Counter) to see the pulse height using Multi-channel Analyzer. The response characteristics of these two kinds of particles in CNCs (TSI CNC 3022 and 3025A) have been studied as a function of particle size using mono disperse particles classified by DMA. The results show that the higher drag resistance particles, so called agglomerated particles have generated a lower CNC pulse height than the spherical particles for these two different CNCs, which means the nonagglomerated particles may start to grow larger than the agglomerated particles.

• Animal cells and systems
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• v.9 no.2
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• pp.65-73
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• 2005

In this study, we found that sperm ball of Urechis unicinctus consisted of a somatic cell and spermatogenic cells. After separation from the sperm ball, individual spermatid floated freely in the coelomic fluid and differentiated into a mature sperm. Because of many nuclear vacuoles, spermatid nucleus was observed to be heterogeneous. Later, the spermatid nucleus condensed into the homogeneous round nucleus of the mature sperm. Perinuclear microtubules could be seen but did not seem to be organized into manchette microtubules. To understand the nature of nuclear condensation during spermiogenesis, the sperm and spermatids (spermiogenic cells) were treated with FITC-phalloidin, or anti-actin-FITC, or labeled with antiactin immunogold particles (AAIP; 10 nm) followed by transmission electron microscopy or confocal laser scanning microscopy. The anti-actin-FITC and FITC-phalloidin reactions occurred distinctly in the nuclei of both spermiogenic cells. FITC-phalloidin reacted more intensely with acrosomes. The AAIP were incorporated mainly into nuclei of both cells sometimes showing local distribution in the nucleus. Nuclear vacuoles of spermatids disappeared progressively with condensation of the nucleus, as the number of incorporated $AAIP/{\mu}m^2$ increased. These results suggest that nuclear actin microfilaments might be closely related to nuclear condensation.

• Korean Journal of Animal Reproduction
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• v.21 no.3
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• pp.229-238
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• 1997

Chromosome condensation and swelling of the donor nucleus have been known as the early morphological indicators of chromatin remodelling after injection of a foreign nucleus into an enucleated recipient cytoplasm. The effects of non-preactivation and electrical preactivation of recipient cytoplasm, prior to fusing a donor nucleus, on the profile of nuclear remodelling in the nuclear transplant rabbit embryos were evaluated. The embryos of 16-cell stage were collected and synchronized to G1 phase of 32-cell stage. The recipient cytoplasms were obtained by removing the first polar body and chromosome mass by non-disruptive microsurgical procedure. The separated G1 phase blastomeres of 32-cell stage were injected into non-preactivated recipient cytoplasms. Otherwise, the enucleated recipient cytoplasms were preactivated by electrical stimulation and the separated G1 phase blastomeres of 32-cell stage were injected. After culture until 20h post-hCG injection, the nuclear transplant oocytes were electrofused by electrical stimulation. The nuclei of nuclear transplant embryos fused into non-preactivated and/or preactivated recipient cytoplasm were stained by Hoechst 33342 at 0, 1.5, 2, 4, 6, 8, 10 hrs post-fusion and were observed under an fluorescence microscopy. Accurate measurements of nuclear diameter were revealed with an ocular micrometer at 200$\times$. Upon blastomere fusion into non-preactivated recipient cytoplasm, a prematurely chromosome condensation at 1.5 hrs post-fusion and nuclear swelling at 8 hrs post-fusion were occurred as 91.6% and 86.1%, respectively. But the nuclei of nuclear transplant embryos fused into preactivated recipient cytoplasm, as o, pp.sed to non-preactivated recipient cytoplasm, were not occurred chromosome condensation and extensive nuclear swelling. Nuclear diameter fused into non-preactivated and preactivated recipient cytoplasm at hrs post-fusion was 30.2$\pm$0.74 and 15.2$\pm$1.32${\mu}{\textrm}{m}$, respectively. These results indicated that onset of unclear condensation and swelling which was associated with oocytes activation were critical steps in the process of chromatin swelling. Futhermore, complete reprogramming seemed only possible after remodelling of the donor nucleus by chromosome condensation and nuclear swelling.

• Asian Journal of Atmospheric Environment
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• v.8 no.4
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• pp.175-183
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• 2014

To visually and chemically verify the rainout of soot particles, a model experiment was carried out with the cylindrical chamber (0.2 m (D) and 4 m (H)) installing a cloud drop generator, a hydrotherometer, a particle counter, a drop collector, a diffusing drier, and an artificial soot particle distributer. The processes of the model experiment were as follows; generating artificial cloud droplets (major drop size : $12-14{\mu}m$) until supersaturation reach at 0.52%-nebulizing of soot particles (JIS Z 8901) with an average size of $0.5{\mu}m$-counting cloud condensation nuclei (CCN) particles and droplets by OPC and the fixation method (Ma et al., 2011; Carter and Hasegawa, 1975), respectively - collecting of individual cloud drops - observation of individual cloud drops by SEM - chemical identifying of residual particle in each individual droplet by SEM-EDX. After 10 minutes of the completion of soot particle inject, the number concentrations of PM of all sizes (> $0.3{\mu}m$) dramatically decreased. The time required to return to the initial conditions, i.e., the time needed to CCN activation for the fed soot particles was about 40 minutes for the PM sized from $0.3-2.0{\mu}m$. The EDX spectra of residual particles left at the center of individual droplet after evaporation suggest that the soot particles seeded into our experimental chamber obviously acted as CCN. The coexistence of soot and mineral particle in single droplet was probably due to the coalescence of droplets (i.e., two droplets embodying different particles (in here, soot and background mineral particles) were coalesced) or the particle capture by a droplet in our CCN chamber.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.221-222
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.227-228
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• 2006

• Particle and aerosol research
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• v.9 no.1
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• pp.7-21
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• 2013

Twelve-hour size-resolved atmospheric aerosols were measured to determine size distributions of water-soluble organic carbon(WSOC) during daytime and nighttime, and to investigate sources and formation pathways of WSOC in individual particle size classes. Mass, WSOC, ${NO_3}^-$, $K^+$, and $Cl^-$ at day and night showed mostly bimodal size distributions, peaking at the size range of $0.32-0.55{\mu}m$(condensation mode) and $3.1-6.2{\mu}m$(coarse mode), respectively, with a predominant condensation mode and a minor coarse mode. While ${NH_4}^+$ and ${SO_4}^{2-}$ showed unimodal size distributions which peaked between 0.32 and $0.55{\mu}m$. WSOC was enriched into nuclei mode particles(< $0.1{\mu}m$) based on the WSOC-to-mass and WSOC-to-water soluble species ratios. The sources and formation mechanisms of WSOC were inferred in reference to the size distribution characteristics of inorganic species(${SO_4}^{2-}$, ${NO_3}^-$, $K^+$, $Ca^{2+}$, $Na^+$, and $Cl^-$) and carbon monoxide. Nuclei mode WSOC was likely associated with primary combustion sources during daytime and nighttime. Among significant sources contributing to the condensation mode WSOC were homogeneous gas-phase oxidation of VOCs, primary combustion emissions, and fresh(or slightly aged) biomass burning aerosols. The droplet mode WSOC could be attributed to aqueous oxidation of VOCs in clouds, cloud-processed biomass burning aerosols, and small contributions from primary combustion sources. From the correlations between WSOC and soil-related particles, and between WSOC and sea-salt particles, it is suggested that the coarse mode WSOC during daytime is likely to condense on the soil-related particles($K^+$ and $Ca^{2+}$), while the WSOC in the coarse fraction during nighttime is likely associated with the sea-salt particles($Na^+$).