• Nuclear Engineering and Technology
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• 제56권1호
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• pp.70-77
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• 2024

A low energy ion irradiation system based on the deuterium arc ion source with a high perveance of 1 µP for a single extraction aperture has been successfully developed for the investigation of ion irradiation on plasma-facing components including the first mirror of plasma optical diagnostics system. Under the optimum operating condition for mirror testing, the ion source has a beam energy of 200 eV and a current density of 3.7 mA/cm². The ion source comprises a magnetic cusp-type plasma source, an extraction system, a target system with a Faraday cup, and a power supply control system to ensure stable long time operation. Operation parameters of plasma source such as pressure, filament current, and arc power with D₂ discharge gas were optimized for beam extraction by measuring plasma parameters with a Langmuir probe. The diode electrode extraction system was designed by IGUN simulation to optimize for 1 µP perveance. It was successfully demonstrated that the ion beam current of ~4 mA can be extracted through the 10 mm aperture from the developed ion source. The target system with the Faraday cup is also developed to measure the beam current. With the assistance of the power control system, ion beams are extracted while maintaining a consistent arc power for more than 10 min of continuous operation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.203-203
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• 2013

Low pressure plasmas play a key role in many areas including electronic, aerospace, automotive, biomedical, and toxic waste management industries, and the advantages of the plasma are well known the processing procedure is established. However, the insight behavior of the discharges remains a mystery, even though a simple geometry as capacitive discharges. In this work, we measured RF power dissipation in capacitively coupled plasma (CCP) at various experiment conditions with potential probe and RF current probe. Through the results, we will have a clearer view of the inner nature of the CCP.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.579-579
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• 2013

We study on Argon metastable and 4p state neutral atom density in magnetized ICP Helicon plasmas by Laser Induced Fluorescence and plasma emission. The results show that metastable density is too low at the center of chamber due to significant neutral depletion. Otherwise, 4p state is high at the center of chamber because electron density is very high. Power and pressure dependence of metastable and 4p state neutral atom have been spatially measured in the radial direction of cylindrical chamber.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.136.1-136.1
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• 2015

In the present study, UHF (320 MHz) in combination with RF (13.56 MHz) plasmas was used for the synthesis of hydrogenated silicon nitride (SiNx:H) films by PECVD process at low temperature. RF/UHF hybrid plasmas were maintained at a fixed pressure of 410 mTorr in the N2/SiH4 and N2/SiH4/NH3 atmospheres. To investigate the radical generation and plasma formation and their control for the growth of the film, plasma diagnostic tools like vacuum ultraviolet absorption spectroscopy (VUVAS), optical emission spectroscopy (OES), and RF compensated Langmuir probe (LP) were utilized. Utilization of RF/UHF hybrid plasmas enables very high plasma densities ~ 1011 cm-3 with low electron temperature. Measurements using VUVAS reveal the UHF source is quite effective in the dissociation of the N2 gas to generate more active atomic N. It results in the enhancement of the Si-N bond concentration in the film. Consequently, the deposition rate has been significantly improved up to 2nm/s for the high rate synthesis of highly transparent (up to 90 %) SiNx:H film. The films properties such as optical transmittance and chemical composition are investigated using different analysis tools.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.208-208
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• 1999

It is found that with increasing power, the measured electron energy distribution by Langmuir probe evolves into a Druyvesteyn-like electron energy distribution in the low-pressure regime of 1mTorr in a small inductively coupled plasma. Electron bounce resonance is introduced to explain the transition of the electron energy distribution against the rf power, The energy diffusion coefficients which determine the shape of the electron energy distribution in elastic range are calculated with and without electron bounce resonance. This electron energy distribution transition is well explained by the electron bounce resonance.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.586-589
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• 2002

The Ultra Violet(UV) emission characteristics of Neon + Nitrogen gas-mixture discharge was investigated in AC plasma display panel. The firing voltage of Ne+$N_2$ gas-mixture discharge increased with increasing nitrogen concentration. The UV intensity emitted from the gas discharge also increased with increasing nitrogen concentration. The UV efficiency increase with increasing $N_2$ partial pressure at low $N_2$ concentration, and then UV efficiency is saturated at high $N_2$ concentration.

• Membrane and Water Treatment
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• 제4권2호
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• pp.109-126
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• 2013

Surface modification by low-pressure ammonia ($NH_3$) plasma on commercial thin-film composite (TFC) membranes was investigated in this study. Surface hydrophilicity, total surface free energy, ion exchange capacity (IEC) and zeta (${\zeta}$)-potentials were determined for the TFC membranes. Qualitative and quantitative analyses of the membrane surface chemistry were conducted by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy. Results showed that the $NH_3$ plasma treatment increased the surface hydrophilicity, in particular at a plasma treatment time longer than 5 min at 50 W of plasma power. Total surface free energy was influenced by the basic polar components introduced by the $NH_3$ plasma, and isoelectric point (IEP) was shifted to higher pH region after the modification. A ten (10) min $NH_3$ plasma treatment at 90 W was found to be adequate for the TFC membrane modification, resulting in a membrane with better characteristics than the TFC membranes without the modification for water treatment. The thin-film chemistry (i.e., fully-aromatic and semi-aromatic nature in the interfacial polymerization) influenced the initial stage of plasma modification.

• Journal of Nutrition and Health
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• 제32권6호
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• pp.671-680
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• 1999

In order to investigate the relationship between plasma renin activity and metabolism of Ca and Na in blood pressure, the habitual dietary intakes of Na and Ca urinary excretion of Ca, Na and K, and plasma level of renin activity, aldosterone, and indices of Ca metabolism were measured in 27 untreated hypertensive women and 30 age-matched normal women on a free diet. Hypertensive subjects were classified into high renin hypertensive (HH), medium renin hypertensive(HM) and low renin showed no significant difference among normotensive, LH, MH and HM groups. It appeared that 25-(OH) Vit D3 level of HH group was significantly higher than LH group(p<0.05). There was significant difference in habitual intake of Ca between normotensive and LH groups. However, habitual intake of Na showed no significant difference among normotensive, LH, MH and HH group. Positive correlation of systolic and diastolic blood pressure with PTH(r=0.324, r=0.375) and urinary Ca(r=0.496, r=0.278) and a negative correlation of systolic blood pressure with habitual Ca intake(r=-0.371) existed(p<0.05). A relative magnitude of factors affecting hypertension was analyzed by multiple regression analysis. Overall results about relative influence of independent variables to dependent variable (systolic blood pressure) indicated that urinary Ca was the higher correlation in all subjects(p<0.0001), followed by age and aldosterone. PTH showed a significant correlation for relative influence on diastolic blood pressure in all subjects. The above results indicated that renin-aldosterone system and Ca regulating hormone had a mutual relationship in hypertension.

• The Korean Journal of Physiology
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• 제24권2호
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• pp.261-268
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• 1990

It has long been suggested that the cardiac atrium is a low pressure volume receptor controlling body fluid volume and blood pressure. Recently, the cardiac atrium has been found to contain a family of powerful peptides. To clarify the relationship between high blood pressure and the biologically active atrial peptides, experiments were done to define the characteristics of atrial natriuretic peptide secretion in the isolated perfused atria of renal hypertensive rats. Higher concentrations of plasma atrial natriuretic peptide and renin activity were observed in the two-kidney, one clip hypertensive rat compared to the normotensive rat. Atrial volume changes in response to pressure elevations were attenuated in hypertensive rats compared to normotensive rats. Incremental response to atrial volume changes in ANP secretion was accentuated in hypertensive rats. These date suggest that the accentuated atrial natriuretic peptide response to volume changes of hypertensive rats may be a physiological or pathphysiological adaptation to the high blood pressure and may be, at least in part, responsible for the elevated levels of plasma atrial natriuretic peptide observed in hypertensive rats.

• 동물자원연구
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• 제30권2호
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• pp.69-78
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• 2019

본 연구는 대기압 플라즈마 처리 자소엽 추출물이 첨가된 소시지의 품질 특성을 알아보기 위해 수행되었다. 본 연구를 위해 자소엽 추출물에 대기압 플라즈마를 처리하여 7.5g kg^-1의 아질산 이온이 함유된 자소엽 추출물 분말을 제조하였으며, 아질산염(Control), 셀러리 분말(Celery) 및 자소엽 추출물 분말(PTP)를 이용 아질산 이온이 70mg kg^-1첨가된 소시지를 제조하였다. 소시지의 잔존 아질산 이온 함량 측정결과 PTP에서 저장 21일 동안 잔존 아질산 이온 함량이 가장 낮았으며, Control 및 Celery와 비교하여 PTP에서 저장 중 총 호기성 미생물수가 높은 것으로 확인되었다(p<0.05). 소시지의 저장 중 malondialdehyde 함량은 PTP에서 Control 및 Celery에 비해 유의적으로 낮음이 확인되었다(p<0.05). 소시지의 육색 측정 결과 모든 저장일차에서 PTP가 낮은 L^* 값과 높은 b^*값을 보였다(p<0.05). 이로 인해 소시지의 관능평가에서 PTP가 Control 및 Celery와 비교하여 낮은 육색 선호도를 보였으며, 풍미 또한 가장 낮은 점수를 받았다. 본 연구의 결과 대기압 플라즈마 처리 자소엽 분말은 천연 아질산 소재로서 염지식육 가공식품 제조에 이용이 적합하지 않음이 확인되었다. 하지만 천연물 추출물에 대기압 플라즈마 처리를 통해 아질산 이온을 생성하여 천연 아질산 소재의 제조가 가능함을 알 수 있었다. 따라서 염지 식육 가공식품의 관능적 품질에 부정적인 영향이 없는 천연물을 탐색하고 이를 플라즈마 처리를 통해 천연 아질산 소재로 개발하면 합성 아질산염 대체가 가능한 천연 아질산 소재로서 육가공품의 염지 공정에 이용이 가능할 것으로 생각된다.