• 한국환경과학회지
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• 제21권6호
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• pp.695-704
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• 2012

The application of disinfection models on the plasma process was investigated. Nine empirical models were used to find an optimum model. The variation of parameters in model according to the operating conditions (first voltage, second voltage, air flow rate, pH) were investigated in order to explain the disinfection model. In this experiment, the DBD (dielectric barrier discharge) plasma reactor was used to inactivate Ralstonia Solanacearum which cause wilt in tomato plantation. Optimum disinfection models were chosen among the nine models by the application of statistical SSE (sum of squared error), RMSE (root mean sum of squared error), $r^2$ values on the experimental data using the GInaFiT software in Microsoft Excel. The optimum model was shown as Weibull+talil model followed by Log-linear+ Shoulder+Tail model. Two models were applied to the experimental data according to the variation of the operating conditions. In Weibull+talil model, Log10($N_o$), Log10($N_{res}$), ${\delta}$ and p values were examined. And in Log-linear+Shoulder+Tail model, the Log10($N_o$), Log10($N_{res}$), $k_{max}$, Sl values were calculated and examined.

• 한국세라믹학회지
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• 제50권5호
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• pp.326-332
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• 2013

In this study, we prepared yttria stabilized zirconia granules for thermal barrier coatings using a spray drying process. First, we characterized the properties of granules such as flow rate and packing density for utilizing the air plasma spray process. The flow rate and packing density data showed 0.732 g/sec and 2.14 $g/cm^3$, respectively, when we used larger and denser particles, which are better than hollow granules or smaller spherical granules. Second, we chose larger, spherical granules fabricated in alcohol solvent as starting powders and sprayed it on the bondcoat/nimonic alloy by an atmospheric plasma spray process varying the process parameters, the feeding rate, gun speed and spray distance. Finally, we evaluated representative thermal and mechanical characteristics. The thermal expansion coefficients of the coatings were $11{\sim}12.7{\times}10^{-6}/^{\circ}C$ and the indentation stress measured was 2.5 GPa at 0.15 of indentation strain.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.768-775
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• 2022

In this study we aimed to derive the response surface models for Escherichia coli reduction in wheat flour using atmospheric cold plasma (ACP) with three types of gas. The jet-type atmospheric cold plasma wand system was used with a 30 W power supply, and three gases (argon, air, and nitrogen) were applied as the treatment gas. The operating parameters for process optimization considered were wheat flour mass (g), treatment time (min), and gas flow rate (L/min). The wheat flour samples were artificially contaminated with E. coli at a concentration of 9.25 ± 0.74 log CFU/g. ACP treatments with argon, air, and nitrogen resulted in 2.66, 4.21, and 5.55 log CFU/g reduction of E. coli, respectively, in wheat flour under optimized conditions. The optimized conditions to reduce E. coli were 0.5 g of the flour mass, 15 min of treatment time, and 0.20 L/min of nitrogen gas flow rate, and the predicted highest reduction level from modeling was 5.63 log CFU/g.

• 한국양식학회지
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• 제14권1호
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• pp.57-64
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• 2001

In Paralichthys olivaceus and Nibea japonica, response to live air (5hr) or ship (25hr) transportation was assessed, by determining the levels of plasma cortisol, glucose, lactic acid and osmolality, as well as hematological parameters namely hematocrit (Ht), red blood cell (RBC) count, hemoglobin (Hb), corpuscular volume (MCV), corpuscular hemoglobin (MCH) and corpuscular hemoglobin concentration (MCHC). In the experimental series I, the olive flounder was subjected to stress or no stress for 1hr, prior to its air transportation for 5hr. The stress suffered by the flounder prior to air transportation resulted in significant reduction in Ht, but increases in MCH and MCHC. Air transportation led to increases in MCV and MCH in both the stressed and non stressed groups. In the non stressed group it led to significant increase in Ht but decrease in MCHC. In the stressed group, the air transportation led to significant increases in osmolality and plasma cortisol from 5 to 38.5ng/$m\ell$. Non stressed groups did not show significant differences in this before and after transportation. In the experiment II, the red blood cell (RBC) count ranged from 2.5$\times$10$^{6}$ /${mu}ell$ to 2.7$\times$10$^{6}$ /${mu}ell$ in the flounder and 1.9$\times$10$^{6}$ /${mu}ell$ to 2.1$\times$10$^{6}$ /${mu}ell$ in the croaker during the pre- and post-transportation, respectively. In the croaker the shipping led to significant increase in plasma cortisol from 26 to 35ng/$m\ell$ but decrease in glucose from 91.0 to 26.4mg/㎗. For glucose the reverse (39.0 to 51.0mg/㎗) was true for the flounder.

• Journal of Preventive Medicine and Public Health
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• 제33권1호
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• pp.45-50
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• 2000

Objectives : This study was undertaken to evaluate correlation between the levels of hippuric acid in blood plasma (HAP) and those of toluene concentration in the workplace air. Methods : Study subjects were composed of two groups; 21 workers who were occupationally exposed to toluene and 25 rural-area residents who were not exposed to any known occupational toluene source, as an exposed group and a reference group, respectively. Mean age and work duration of the exposed was 42 years and five years, respectively. Mean age of the reference was 42 years. To determine toluene concentrations in the workplace air, air sampling has been conducted for more than six hours using a personal sampler, and analyzed by a gas chromatography-flame ionization detector. Concentrations of hippuric acid in biological samples were determined by a high performance liquid chromatography-ultraviolet detector. Results : Geometric mean(geometric standard deviation) of HAP and hippuric acid in urine(HAU) for the exposed was 1.39(2.21) mg/L and 2.77(1.46) g/L, respectively, which were significantly different from those of the reference [HAP, 9.45(2.94); HAU, 0.37(0.45)]. Teluene concentration in the workplace air was 86.92(range: $45.18\sim151.23$)ppm. The level of HAP or HAU was significantly correlated (r=0.70 and r=0.63, respectively) with that of toluene in the workplace air. The estimated regression equation was logHAP(mg/L)=-3.60+1.93 log(toluene, ppm) or logHAU(g/L)=-0.85+0.67 log(toluene, ppm). The magnitude of correlation was further enhanced when analyzing relationship between toluene concentrations lower than 100 ppm and its corresponding HAP levels. Conclusion : Overall, plasma hippuric acid levels were well correlated with toluene concentrations in the workplace air, and a statistically significant correlation was observed for the samples with toluene concentration lower than 100 ppm.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권3호
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• pp.143-154
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• 2013

Purpose: This study was to find efficacy of integrin alpha2 (${\alpha}_2$) and epidermal growth factor receptor (EGFR) as tumor marker of oral squamous cell carcinoma (SCC) and clarify the selective cell death effect of anti-integrin ${\alpha}_2$ and anti-EGFR on SCC cells, additionally testify conjugated gold nanoparticles (GNP) with air plasma for selective cell death of oral SCC. Methods: Expression of integrin ${\alpha}_2$, EGFR on human SCC cells (SCC25) were examined by western blot. SCC25 cells were treated with anti-integrin ${\alpha}_2$, anti-EGFR and analysed by Hemacolor staining, immunoflorescence staining, FACS flow cytometry. Conjugated GNP with integrin ${\alpha}_2$, EGFR antibody were treated by air plasma on SCC cells. Results: Integrin ${\alpha}_2$ and EGFR were over-expressed on SCC25 cells than normal lung WI-38 cells. The cell viability rate of SCC25 cells treated with anti-integrin ${\alpha}_2$, anti-EGFR was lower than WI-38 cells. The concentration changes of nucleus, releasing cytochrome c and apoptosis inducing factor (AIF) from mitochondria to cytosol were observed. The changes of proteins related with apoptosis were observed. Increase of bax, bcl-xL, activation of caspase-3, -7, -9, and fragmentation of PARP, DFF45 and decrease of lamin A/C in SCC25 cells were observed. In FACS, increase of sub-$G_1$ and S phase was observed. Cell cycle related proteins, Such as cyclin D1, cyclin dependent kinase (CDK) 4, cyclin A, cyclin E, CDK 2, p27 were decreased. After SCC25 cells treated with conjugatged GNP-Integrin ${\alpha}_2$, GNP-EGFR, additionally air plasma, the cell death rate was significantly increased. Conclusion: Integrin ${\alpha}_2$, EGFR were over-expressed in oral SCC cells. Anti-integrin ${\alpha}_2$, anti-EGFR in SCC25 cells induced apoptosis selectively. When GNP-anti integrin ${\alpha}_2$, GNP-anti EGFR were treated with air plasma on SCC25 cells, cancer cells were died more selectively. GNP-anti integrin ${\alpha}_2$, GNP-anti EGFR with air plasma could be treatment choice of oral SCC.

• Applied Science and Convergence Technology
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• 제24권5호
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• pp.196-202
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• 2015

Human blood consists of 55% of plasma and 45% of blood cells such as white blood cell (WBC) and red blood cell (RBC). In plasma, there are many kinds of promising biomarkers, which can be used for the diagnosis of various diseases and biological analysis. For diagnostic tools such as a lab-on-a-chip (LOC), blood plasma separation is a fundamental step for accomplishing a high performance in the detection of a disease. Highly efficient separators can increase the sensitivity and selectivity of biosensors and reduce diagnostic time. In order to achieve a higher yield in blood plasma separation, we propose a novel fluid wing structure that is optimized by COMSOL simulations by varying the fluidic channel width and the angle of the bifurcation. The fluid wing structure is inspired by the inertial particle separator system in helicopters where sand particles are prevented from following the air flow to an engine. The structure is ameliorated in order to satisfy biological and fluidic requirements at the micro scale to achieve high plasma yield and separation efficiency. In this study, we fabricated the fluid wing structure for the efficient microfluidic blood plasma separation. The high plasma yield of 67% is achieved with a channel width of $20{\mu}m$ in the fabricated fluidic chip and the result was not affected by the angle of the bifurcation.

• 한국세라믹학회지
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• 제39권4호
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• pp.409-412
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• 2002

대기압 하에서 정상적으로 저온 플라스마가 발생 가능한 장치를 개발했다. 개발한 장치는 접지전극을 유전체로 피복한 용량결합형 전극구조로 되어 있다. rf(13.56 M Hz)을 여기 원으로서 사용한 아르곤(Ar) 또는 헬륨(He)은 플라스마 가스로서 사용했다. 발생한 플라스마는 발광분광법, 플로브 진단법에 의해 특성을 검토했다. 그 결과 전자온도>여기온도>가스온도 관계에 있는 비평형 상태의 플라스마였다. 본 장치를 사용하여 발생한 플라스마에 반응가스(CF4)을 첨가해서 대기 개방 계에서 Si(100)식각($1.5{\mu}m$/min)에 적용하여 높은 처리속도를 실현했다.

• Korean Chemical Engineering Research
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• 제48권5호
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• pp.556-560
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• 2010

부타디엔 고무 소재의 접착력을 향상시키기 위하여 대기압 표면개질방식을 적용시켰다. 평판형 플라즈마반응기의 최적의 반응조건을 구하기 위하여 반응기체(질소, 아르곤, 산소, 공기), 기체유량(30~100 mL/min), 플라즈마 처리시간(0~30초) 및 선처리제의 개질방법(GMA, 2-HEMA)을 변화시켜 실험하였다. 처리 전후의 소재의 표면변화는 SEM과 ATR-FTIR로 측정하였다. 기체의 유량과 처리시간이 증가함에 따라 접촉각이 감소하였고, 반응 기체는 공기로 유량 60 mL/min, 처리시간 5초 및 2-HEMA 첨가 선처리제를 사용하였을 때 최대의 접착박리강도를 나타내었다. 결과적으로 대기압식 평판형 플라즈마 처리방식으로 고무소재 표면의 젖음성과 접착박리강도가 개선되었음을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2918-2922
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• 2007

This is a report of a feasibility study on the reduction of harmful substances such as particulate matters and nitric oxides emitted from diesel engines by using a plasma reforming system that can generate hydrogen-rich gas. In this paper, an exhaust reduction mechanism of the non-thermal plasma reaction was investigated to perform its efficiency and characteristics on producing hydrogen-rich gas. Firstly, we explain briefly the chemistry of hydrocarbon reforming. The experimental system is showed in the second part. Finally, we demonstrate the feasibility of producing hydrogen using non-thermal plasma. The experimental results are focused on the influence of the different operating parameters (air ratio, inlet flow rates, voltage) on the reformer efficiency and the composition of the produced gas.