• International Journal of Oral Biology
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• v.32 no.3
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• pp.93-101
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• 2007

Cell behavior of the transformed cells is known to affect by interaction with extracellular matrix (ECM) proteins and integrin. To investigate the alterations of both integrin expression and cell-matrix interaction during neoplastic conversion of human oral kerationcytes, we studied expression levels of integrin subunits by flow cytometry and cellular responses to the ECM proteins in normal human oral keratinocytes (NHOKs), HPV-immortalized HOK-16B line, and three oral cancer cell lines established from HOK-16B line, CTHOK-16B-BaP, CTHOK-16B-DMBA, and CTHOK-16B-Dexa lines. The expression levels of ${\alpha}\;and\;{\beta}$ integrin subunits were shown decreased tendency in human oral keratinocytes undergoing immortalization and tumorigenic transformation except CTHOK-16B-DMBA line tested. Although ${\alpha}v{\beta}6$ integrin is known to be highly expressed in squamous cell carcinomas, and the altered integrin expression is suspected to be associated with cellular carcinogenesis, ${\alpha}v$ integrin subunit and ${\alpha}v{\beta}6$ integrin did not express in oral cancer cell lines tested. Cell behavior to the ECM proteins in HOK-16B line was generally similar to that of exponentially proliferating NHOKs. The adhesion activity profiles of type I collagen were very similar to that of its laminin counterparts, but fibronectin showed minimal adhesion activity under our conditions compared to the BSA control. The ability of the CTHOK-16B-BaP line to spread upon type I collagen and laminin markedly decreased, but migration was notably increased on type I collagen. In contrast, CTHOK-16B-DMBA and CTHOK-16B-Dexa lines spread less but migrated more upon type I collagen than immortalized HOK-16B line. These data indicate that downregulation of integrin subunits causes the changes of cellular responses to the ECM proteins during neoplastic conversion of human oral keratinocytes, and that cellular responses to the ECM proteins in oral cancer cell lines established by exposing different carcinogens are variable according to chemical carcinogens treatment.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.2
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• pp.69-74
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• 2005

Since the use of CFC and HCFC refrigerants is to be restricted due to the depletion of ozone layer, this experiment applies the $NH_{3}$ gas to study the performance characteristics from the superheat control for improving the energy efficiency. The experiments are carried out for the condensing pressure of refrigeration system from 1500kPa to 1600kPa by 50kPa and for degree of superheat from $0^{circ}$ to $1^{circ}$ by $10^{circ}$ at each condensing pressure. As a result of experiment, 1) As degree of superheat increased, evaporating pressure of the compressor decreased so equilibrium temperature decreased. And specific volume of refrigerant vapors increased so refrigerant mass flow and heat load of the evaporator decreased. 2) An influence of change of condensing pressure on heat load of the evaporator was insignificant. 3) With the identical degree of superheat, change of compressed temperature was insignificant according to each condensing pressure, so there was little change in enthalpy.4) when the degree of superheat is $0^{circ}$C at each condensing pressure, the refrigeration system has the hi띤est performance.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.100-109
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• 1994

In this study, it is investigated that the possibility of the numerical simulation for the incineration of the hazardous material, crbon tetrachloride($CCl_4$). A 3-dimensional numerical technology is applied for turbulent reacting flows of the full-scale Dow Chemical incinerator. The calculations are made by a CRAY-2S, super computer. The major parameters considered in this study are kiln revolution rate (rpm), filling ratio of the solid waste(f), burner Injection velocity and angle, and turbulent air jets for swirl. And the employed turbulent reaction model is the eddy break-up model which is a kind of fast chemistry model assuming general equilibrium and used for a premixed flame. The calculated flow fields are presented and discussed. 1) The presence of turbulent air nozzles for swirl gives rise to visible increase of the convective motion over the region of the solid waste. This implies the possibility to enhance the mixing of the waste with the surrounding all and thereby to reduce thermal and species stratification, which were reported in a large rotary kiln operation. 2) Considering that the location of the recirculation region has a strong relation with the heating rate of the solid waste, the control of the recirculation region by the burner injection angle Is quite desirable in the sense of the flexible design of the rotary kiln incinerator for a carbon tetrachloride. 3) Finally, it is found that the eddy break-up model Is not suitable for carbon tetrachloride($CCl_4$) because this model is not incorporated the flame inhibition trend due to the presence $CCl_4$compound.

• Advances in nano research
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• v.5 no.3
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• pp.261-279
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• 2017

Spectroscopic investigation of Si quantum dots (Si-QDs) embedded in silicon nitride was performed over a broad stoichiometry range to optimize light emission. Plasma-enhanced chemical vapor deposition was used to grow the $SiN_x$ films on Si (001) substrates. The film composition was controlled via the flow ratio of silane ($SiH_4$) and ammonia ($NH_3$) in the range of R = 0.45-1.0 allowed to vary the Si excess in the range of 21-62 at.%. The films were submitted to annealing at $1100^{\circ}C$ for 30 min in nitrogen to form the Si-QDs. The properties of as-deposited and annealed films were investigated using spectroscopic ellipsometry, Fourier transform infrared spectroscopy, Raman scattering and photoluminescence (PL) methods. Si-QDs were detected in $SiN_x$ films demonstrating the increase of sizes with Si excess. The residual amorphous Si clusters were found to be present in the films grown with Si excess higher than 50 at.%. Multi-component PL spectra at 300 K in the range of 1.5-3.5 eV were detected and nonmonotonous varying total PL peak versus Si excess was revealed. To identify the different PL components, the temperature dependence of PL spectra was investigated in the range of 20-300 K. The analysis allowed concluding that the "blue-orange" emission is due to the radiative defects in a $SiN_x$ matrix, whereas the "red" and "infrared" PL bands are caused by the exciton recombination in crystalline Si-QDs and amorphous Si clusters. The nature of radiative and no radiative defects in $SiN_x$ films is discussed. The ways to control the dominant PL emission mechanisms are proposed.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.77-86
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• 2005

A monitoring study has been conducted to identify hydrologic conditions, water quality and nutrient loading characteristics of small watershed in Juam Lake. Climate data of the watershed were collected; flow rate was measured and water quality sampling was conducted at the watershed outlet for this study. Water quality data revealed that T-P concentrations meet I grade of lake water quality standard during non-storm period, but degraded up to II-III grade of lake water quality standard during storm period. The observed T-N concentrations always exceeded lake water quality standard. Therefore, T-P was identified as limiting chemical constituent for eutrophication of Juam Lake. T-P concentration of non-storm period also revealed that point source pollution is not serious in the watershed. Three year monitoring results showed that the observed T-N losses were $10.85\~18.88$ kg/ha and T-P losses were $0.028\~0.323$ kg/ha during six month (Mar. - Oct.), respectively. Major portion of runoff amount discharged by a few storm events a year and nutrient load showed apparent seasonal variation. Huge runoff amounts were generated by intense storms, which make application of water treatment or detention facilities ineffective. Monitoring results confirmed that water quality improvement by abating nonpoint source pollution in rural watershed of monsoon climate should be focused on source control. T-P losses from paddy field seemed to consist of significant amount of total load from study watershed. Therefore, management of drainage from paddy field is considered to be important for preventing algal blooming problem in Juam Lake.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.683-688
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• 2016

The effects of dietary supplementing natural additives [yacon (YC), ginger (GG), and blueberry (BB)] on growth, feed utilization, and body composition of juvenile rockfish were compared to those of ethoxyquin (EQ), which is commonly used to prevent rancidity of fish feed. A total of 480 fish were distributed randomly into 12 50-L flow-through tanks (40 fish/tank). Four experimental diets were prepared: the control diet (Con) with 0.01% EQ, and the YC, GG and BB diets containing 1% YC, GG, and BB instead of wheat flour. Each diet was assigned randomly to triplicate tanks of fish, which were hand fed to satiation twice daily for 8 weeks. Weight gain of fish fed the YC diet was higher than that of fish fed all other diets. Feed efficiency (FE), protein efficiency ratio (PER), and protein retention (PR) in fish fed the YC diet were higher than those in fish fed the other diets. Whole-body chemical composition of the fish was affected by the additive sources. In conclusion, dietary supplementation with GG effectively improved weight gain and feed utilization (FE, PER, and PR) of juvenile rockfish.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.144-144
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• 2013

Non-thermal atmospheric pressure plasmas have recently garnered much attention due to their unique physical and chemical properties that are sometimes significantly different from those of low pressure plasmas. It can offer many possible application areas including nano and bio/medical areas. Many different types of plasma sources have been developed for specific needs, which can be one of the important merits of the atmospheric pressure plasmas since characteristics of the produced plasma depend significantly on operating parameters such as driving frequency, supply gas type, driving voltage waveform, gas flow rate, gas composition, geometrical factor etc. Among many source configurations, parallel plate type geometry is one of the simplest configurations so that it can offer many insights for understanding basic underlying physics. Traditionally, the parallel plate type set up has been studied actively for understanding low pressure plasma physics along with extensive employment in industries for the same reason. By considering that understanding basic physics, in conjunction with plasma-surface interactions especially for nano & bio materials, should be pursued in parallel with applications, we investigated atmospheric pressure discharge characteristics in a parallel plate type capacitive discharge source with two parallel copper electrodes of 60 mm in diameter and several millimeters in gap distance. In this presentation, some plasma characteristics by varying many operating variables such as inter-electrode distance, gas pressure, gas composition, driving frequency etc will be discussed. The results may be utilized for plasma control for widening application flexibility.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.6
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• pp.767-773
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• 2017

Infrared stealth is an important technology for naval ships. This technology helps improve the anti-detection performance and survivability of naval ships. In general, the infrared signature of naval ships are categorized into internal and external heat source. External signature are generated by ship surface heating by solar flux as well as the complicated heat transfer process with the surrounding weather condition. Modern naval ships are equipped with seawater injection nozzles on the outside for nuclear, biological and, chemical, and these nozzles are used to control external signature. Wide nozzle placement intervals and insufficient injection pressure, however, have reduced seawater dispersion area. To address this problem, nozzle installation standards must be established. In this study, an actual-scale experimental system was implemented to provide the evidence for nozzle installation standards in order to reduce the infrared signature of naval ships. In addition, the environmental conditions of the experiment were set up through computational fluid dynamics considering the ocean climate data and naval ship management conditions of South Korea. The dispersion distance was measured using a high-resolution thermography system. The flow rate, pipe pressure, and dispersion distance were analyzed, and the evidence for the installation of seawater injection nozzles and operation performance standards was suggested.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.499-504
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• 2009

Erythrosine is used a food coloring, ink and dye, etc. but erithrosine is rarely used in United States due to its known hazards. The adsorption characteristics of erythrosine by granular activated carbon were investigated in the batch adsorber and the packed column. The adsorptivity of activated carbon for erythrosine were largely improved by pH control. When the pH was 11 in the sample, the erythrosine could be removed 98% of initial concentration. It was estabilished that the adsorption equilibrium of erythrosine on granular activated carbon was successfully fitted by Freundlich isotherm equation in the concentration range from 10mg/L to 1,000mg/L. The characteristics of breakthrough curve of activated carbon packed column depend on the design variables such as initial concentration, bed height, and flow rate.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.475-481
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• 2006

The major problem in closing water like lakes and ponds in Korea is that because they are exposed to surrounding, so easily polluted. The pollution in closing water can be caused by not only artificial factor like sewage but also natural factor like elution from sediment. For insurance of safe and satisfied water source, lots of studies and projects are now going on. In this study, we examined the behavior and effect of microbubble ($3{\sim}10{\mu}m$) produced by device called O.S.D (Oxygen Solubillization Device) in small size pond. The value of oxygen transfer coefficient ($K_La$) was 0.68/min independently of air flow rate, 6.5 times higher than commercial aeration stone and the variation of nitrogen concentration was $0.008NO_3/O_2$, DO concentration was potentially saturated for 24 hr. From the results of pilot plant, SOD of experiment (O.S.D) and control were $12.18gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ and $47.95gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ respectively. In conclusion, because O.S.D has extraordinary physico-chemical characteristics, it can contribute to improvement of both the waterbody and the sediment environment.