• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.271-277
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• 2004

As one of the concepts of the laser/electric hybrid propulsion system, a feasibility study on possibilities of electrostatic acceleration of a laser ablation plasma induced from a solid target was conducted. Energy distributions of accelerated ions were measured by a Faraday cup. A time-of-flight measurement was also conducted for ion velocity measurement. It was found that an average speed of ions from a pure laser ablation in this case was about 20 km/sec for pulse energy of 40 $\mu$J/pulse with pulse width of 250 psec. On the other hand, through an electrostatic field with a + I ,000 V electrode, the speed could be accelerated up to 40 km/sec. It was shown that the electrode with positive potential was more effective than that with negative potential for positive-ion acceleration in laser induced plasma, or pulsed plasma, in which ions were induced with the Coulomb explosion following electrons. In addition, the ion-acceleration or deceleration strongly depended on conditions of pairs of inner diameter and electrodes gap.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.570-571
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• 2005

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1\rightarrow6^3P_2$) were larger than 404.8nm ($6^3S_1\rightarrow6^3P_1$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the L1F signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.111-115
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• 2009

We present a study on the reflection of optically controlled microwave pulses from non uniform plasma layers in semiconductors. The transient response of the microwave pulses in different plasma layers has been evaluated by means of the reflection function of dielectric microstrip lines. The lines were used with an open-ended termination containing an optically induced plasma region, which was illuminated by a light source. The reflection characteristics impedance resulting from the presence of plasma is evaluated by means of the equivalent transmission line model. We have analyzed the variation of the transient response in a 0.01 cm layer with a surface frequency in the region of 128 GHz. In the reflection the variation of the diffusion length $L_D$ is large compared with the absorption depth $1/{\alpha}_l$. The variation of the characteristic response of the plasma layer with differentially localized pulses has been evaluated analytically. The change of the reflection amplitude has been observed at depths of 0.1 cm, 0.01 cm and $0.1{\times}10^{-5}$ cm respectively.

• Preventive Nutrition and Food Science
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• 제2권2호
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• pp.149-154
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• 1997

The ability of exercise and buckwheat diet to modify plasma glucose and cholesterol levels in streptozotocin-induced diabetic rats has been studied. Diabetic rats were fed corn starch as a control diet or buckwheat as an experimental diet for 4 weeks. One group of rats were exercise-trained to swim for 60 min/day, 6 days a week. Plasma glucose levels of sedentary rats both on the control diet and on the buckwheat diet were significantly increased from 367.0$\pm$33.6 mg/dl to 545.0$\pm$38.7 mg/dl and from 380.3$\pm$18.9 mg/dl to 540.5$\pm$36.6 mg/dl, respectively. However, this large increase of plasma glucose was not seen in exercised rats on the buckwheat diet (from 345.0$\pm$25.6 mg/dl to 391.4$\pm$34.7 mg/dl). The total plasma cholesterol level was not affected by either diet or exercise. The HDL-cholesterol level tends to increase due to the buckwheat diet or an exercise, but not with a significant increase. Our results suggest that the buckwheat diet is beneficial in lowering the plasma glucose level only when diabetic rats ar exercised.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.121.1-121.1
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• 2014

Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.

• Journal of Nutrition and Health
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• 제33권7호
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• pp.703-711
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• 2000

The purpose of this study was to investigate the effect of butanol(BuOH) fraction of Polygonatum odoratum with selenium tr-eatment on blood glucose levels and lipid peroxidations in streptozotocin(STZ) induced diabetric rats. Male Sprague-Dawly rats weighing(180-200g) were divided into five groups : normal STZ-control and three expreimental groups(P, odoratum group P, odo-Se group and Se group) Diabetes mellitus was induced by injection STZ in the tail vein at the dose of 45mg/kg B.W The BuOH fraction of Polygonatum odoratum(500mg/kg. B,W) given orally administered for 14 days. The Se treated group were fed a AIN-76 recommendation diet mixed with Na2Seo3(2mg/kg diet). Diabetic rats showed the lower weight gain compared to the normal rats. the plasma glucose levels of the P. odo-Se group were significantly lower than the other experimental groups. The plasma cholesterol levels were higher in STZ-control and Se groups compared toP.odoratum and P. odo-Se groups and HDL-cholesterol levels were increased in the diabetic experimental groups fed on BuOH fraction of P. odoratum with Se supplementation. The liver and muscle glycogen levels were not significantly differ among all groups. The plasma free fatty acid levels were lower in diabetic experimental groups fed on BuOh fraction of P. odoratum or Se sup-plementation than STZ-control and Se groups. Diabetics rats showed the higher levels of triglyceride in plasma andlower levels in liver compared with the normal group. Supplementation with Se decreased significantly the liver triglyceride level. The MDA levels in liver and kidney were significantly reduced in all the experimental groups. In conclusion administration of BuOH fraction of Polygonatuum odoratum with selenium supplementation reduced blood glucose levels and peroxdative tissue damage in STZ induced diabetic rats showing the possibility of preventiave and therapeutic use of the wild edible plant to the diabetes mellitus.

• 한국항공우주학회지
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• 제48권12호
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• pp.1013-1020
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• 2020

스파크 유도 플라즈마 분광법 (SIBS)은 전기 스파크를 사용하여 강력한 플라즈마를 유도한 후 원자 방출 스펙트럼 신호를 수집하는 방법이다. 이 연구는 우주 탐사에 활용되는 기존의 레이저 유도 분해 분광법 (LIBS) 대신 SIBS를 사용할 수 있는지의 잠재력을 보기 위해 진행되었다. 과거에는 SIBS를 사용하여 부피가 큰 고체 샘플을 대상으로 실험하는 것이 성공적이지 않았기 때문에, 본 연구에서는 전극 위치 및 전극 재료의 SIBS의 최적화 연구가 수행되었다. LIBS를 사용할 때에 비해 SIBS의 검출 한계 (LOD)가 78에서 20ppm으로 최대 4배 향상되어 있음을 볼 수 있었다. 생성된 플라즈마의 더 높은 에너지로 인해, SIBS에 의한 신호 세기는 동일한 분광계 설정에서 LIBS보다 3배 정도 높았다.

• Journal of Advanced Marine Engineering and Technology
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• 제20권5호
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• pp.93-102
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• 1996

Laser-induced plume and laser-target interaction during pulsed laser deposition are demonstrated for a lead zirconate titanate (PZT). A KrF excimer laser (wavelength 248nm) was used and the laser was pulsed at 20Hz, with nominal pulse width of 20ns. The laser fluence was~$16J/cm^2,$ with 100mJ per pulse. The laser-induced plasma plume for nanosecond laser irradiation on PZT target has been investigated by optical emission spectra using an optical multichannel analyzer(OMA) and by direct observation of the plume using an ICCD high speed photography. OMA analysis showed two distinct ionic species with different expansion velocities of fast or slow according to their ionization states. The ion velocity of the front surface of the developing plume was about $10^7$cm/sec and corresponding kinetic energy was about 100eV. ICCD photograph showed another kind of even slower moving particles ejected from the target. These particles considered expelled molten parts of the target. SEM morphologies of the laser irradiated targets showed drastic melting and material removal by the laser pulse, and also showed the evidence of the molten particle ejection. The physics of the plasma(plume) formation and particle ejection has been discussed.

• Biomolecules & Therapeutics
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• 제21권6호
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• pp.476-480
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• 2013

Obesity is one of the most serious health problems in developed countries. It negatively affects diverse aspects of human wellbeing. Of these, a relationship between obesity and depression is widely recognized but biomarkers for assessment of obesity-associated mood changes in animal obesity models are rarely known. Here we explored the link between obesity and the plasma levels of monoamine neurotransmitters involved in mood control using a sensitive UPLC/MSMS technique in high fat diet (HFD)-induced obesity model in male C57BL/6 mice to explore the potential utility of plasma tests for obesity-associated mood change. HFD (60% of total calories, 8 weeks) induced significantly higher weight gains in body (+37.8%) and fat tissue (+306%) in male C57BL/6 mice. Bioanalysis of serotonin, dopamine and norepinephrine in plasma at 8 weeks of HFD revealed that serotonin decreased significantly in the obese mice when compared to normal diet-fed mice ($2.7{\pm}0.6$ vs $4.3{\pm}2.0ng/ml$, N=8). Notably, a negative correlation was found between the levels of serotonin and body weight gains. Furthermore, principal component analysis (PCA) with the individual levels of neurotransmitters revealed that plasma levels of dopamine and serotonin could apparently differentiate the obese mice from lean ones. Our study demonstrated that blood plasma levels of neurotransmitters can be employed to evaluate the mood changes associated with obesity and more importantly, provided an important clue for understanding of the relationship between obesity and mood disorders.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.214-215
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• 2000

레이저로 발생시킨 플라즈마의 분광학적인 분석은 유용한 분석기술로 평가되고 있다. 이러한 플라즈마를 발생시키는데 있어서 Q-switched 레이저를 많이 사용되고 되고 있으나, Q-switch된 레이저로 발생시킨 플라즈마 복사광의 특성은 주변 분위기에 의해 매우 큰 영향을 받는다. 특히 대기압인 공기분위기에서 레이저로 발생된 플라즈마의 분광특성은 강하고 연속적인 background가 포함되고, 자체적으로 흡수되고, 넓게 퍼진 분광선들이 생성된다. 이는 레이저 발생 플라즈마를 통해 성분을 분석할 경우에 적합하지 않다. (중략)