• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.179-179
• /
• 2012

Low pressure radio-frequency glow discharges are investigated using theoretical modeling and various experimental diagnostic methods. In the calculations, global models and transformer models are developed to understand the chemical kinetics as well as the electrical properties such as the effective collision frequency, the heating mechanism and the power transferred to the plasma electrons. In addition, Boltzmann equation solver is used to compensate the effect of the electron energy distribution function (EEDF) shape in the global model, and the general expression of energy balance for non-Maxwellian electrons is developed. In the experiments, a number of traditional plasma diagnostic methods are used to compare with calculated results such as Langmuir probe, optical emission spectroscopy (OES), optical absorption spectroscopy (OAS) and two-photon absorption laser-induced fluorescence (TALIF). These theoretical and experimental methods are applied to understand several interesting phenomena in low pressure ICP discharges. The chemical and physical properties of low pressure ICP discharges are described and the applications of these methods are discussed.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.11a
• /
• pp.292-293
• /
• 2002

대기 중에서 HOx(OH, H $O_2$) 라디칼은 가장 중요한 산화제로서 광화학 반응의 핵심적 역할을 한다. 이러한 OH 라디칼의 정확한 농도를 측정하기 위한 여러 가지 시도가 있었으나, 그 존재량이 적고 수명이 짧기 때문에 측정에 많은 어려움이 있다. 간접적인 측정에 근거한 모델링과 계산적인 이론 값에 의하면 대류권에서의 전 지구적 평균 OH 라디칼의 농도는 대략 $10^{6}$molecules $cm^{-3}$이고, H $O_2$ 라디칼의 농도는 $10^{8}$molecules $cm^{-3}$정도로 추정된다. (중략)

• Bulletin of the Korean Chemical Society
• /
• v.25 no.8
• /
• pp.1130-1132
• /
• 2004

Photodissociation dynamics of tert-butyl isocyanide at 193 nm has been investigated by measuring rotationally resolved laser induced fluorescence spectra of CN fragments that were exclusively produced in the ground electronic state. From the spectra, internal energies of CN and translational energy releases in the products were obtained. The dissociation takes place in the excited triplet states which are strongly repulsive along the dissociation coordinate via curve crossing from the initially prepared state.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.9
• /
• pp.1685-1688
• /
• 2008

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.1-14
• /
• 2004

Experiments were performed in order to examine the stability of hydrocarbon-fueled flames in cavity flameholders in supersonic airflows. Methane and ethylene were burned in two different cavity configurations having aft walls ramped at 22.5 and 90$^{\circ}$. Air stagnation temperatures were 590 K at Mach 2 and 640 K at Mach 3. Lean blowout limits showed dependence on the air mass flowrates. Visual observations, planar laser induced fluorescence (PLIF) of nitric oxide (NO), and Schlieren imaging were used to investigate these phenomena. Large differences were noted between cavity floor and cavity ramp injection schemes. Cavity ramp injection provided better performance in most cases. Ethylene pilots have a wider range of stable operation than methane. Fuel flowrates at ignition showed similar trends as lean blowout limits, but higher flowrates were required.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.10
• /
• pp.1076-1082
• /
• 1997

The infrared, Raman, and jet-cooled laser-induced fluorescence excitation spectra of 1,2,3,4-tetrahydronaphthalene have been recorded and analyzed. The observed vibrations have been assigned to understand the conformational behaviors in its electronic ground (S0) and excited (S1) states. Ab initio at the HF/6-31G** level and molecular mechanics (MM3) force field calculations have been carried out to generate the complete normal mode frequencies of the molecule in its S0 state. The vibrational frequencies calculated from the ab initio method show a better agreement with the observed infrared and Raman frequencies than those calculated from the MM3 method. In several cases, the normal mode calculations were very helpful to clarify some ambiguities of previous assignments. In addition, the ring inversion process between two twisted conformers of 1,2,3,4-tetrahydronaphthalene has been reexamined utilizing ab initio calculation. The results show that the ring inversion energy is in the range of 3.7-4.3 kcal/mol which is higher than the previously reported AM1 value of 2.1 kcal/mol.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.4
• /
• pp.341-344
• /
• 1995

Laser-induced fluorescence (LIF) excitation spectra were measured for fluorene (FR) cooled in pulsed supersonic expansions of He in the range 283.7-296.7 nm. Ab initio studies of FR have also been carried out for determining the electronic and vibrational structures by using the standard 3-21G basis sets. In the LIF excitation spectra of FR, highly resolved vibronic bands are observed having the band origin of 33,791 cm-1. The vibrational bands above the electronic origin were assigned on the basis of the well-characterized electronic vibrational bands reported previously and of normal modes of vibrations derived by our HF/3-21G calculations.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.36 no.3
• /
• pp.215-219
• /
• 2010

In this study, we investigated effects of Monegy (mixture of Sophorae Radix, Panax ginseng, Salvia miltiorrhiza BUNGE) on epilate-induced hair-loss in dorsal region of C57/BL6 mice and external structure of human hair. For morphological and histological analysis in scalp of epilate-induced hair-loss animal model, we utilized several microscopic techniques, such as confocal laser scanning microscopy (CLSM) and LAS 4000. Confocal analysis showed the distribution of FITC-conjugated Monegy and penetration depth compared with normal and control group. Furthermore, when Monegy was topically administrated onto a C57BL6 mouse, it penetrated very well. The fluorescence intensity was increased upto 205 and 113 folds compared to normal and control group, respectively. Also, area of fluorescence was increased to upto 255 to 127 folds compared to normal and control group. Broad scale area of fluorescence in dermis region was observed in the Monegy-treated mice. Furthermore, Monegy induced upto 75% hair repair against depilation. It might be promoted via the induction of growth factors in hair follicle.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.8 no.4
• /
• pp.233-239
• /
• 2003

For the quantitative analysis of an unknown sample a calibration curve should be obtained, as analytical instruments give relative, rather than absolute measurements. Therefore, researchers should make standard samples with various known concentrations, measure each standard and the unknown sample, and then determine the concentration of the unknown by comparing the measured value to those of the standards. These procedures are tedious and time-consuming. Therefore, we developed a polymer based microfluidic device from polydimethylsiloxane, which integrates serial dilution and capillary electrophoresis functions in a single device. The integrated microchip can provide a one-step analytical tool, and thus replace the complex experimental procedures. Two plastic syringes, one containing a buffer solution and the other a standard solution, were connected to two inlet holes on a microchip, and pushed by a hydrodynamic force. The standard sample is serially diluted to various concentrations through the microfluidic networks. The diluted samples are sequentially introduced through microchannels by electro-osmotic force, and their laser-induced fluorescence signals measured by capillary electrophoresis. We demonstrate the integrated microchip performance by measuring the fluorescence signals of fluorescein at various concentrations. The calibration curve obtained from the electropherograms showed the expected linearity.

• The Journal of Internal Korean Medicine
• /
• v.21 no.4
• /
• pp.621-631
• /
• 2000

Objective : In this study, the medicine herbs above were directly treated to cultured normal lung cells and lung carcinoma cells, and the effects were investigated to develope new cancer treatments with increased anti-cancer efficiency as well as decreased side-effects and to suggest more useful clinical therapies. Materials and Methods : In the experiment, WI-26 VA lung normal cell line and A-427 lung carcinoma cell line were cultured. To observe the morphological change of the treated cells, were subjected to Giemsa staining and observed under Reflected Fluorescence microscope. To examine whether cell death occurred, cells observed under Reflected Fluorescence microscope, To investigate the degree of cell death in the nucleus, cells were screened by Laser cytometry ACAS 570. Results : Samgibopye-tang(Shenqibufei-tang) stimulated not only the growth of the normal cells but also that of the carcinoma cells, Wikyeung-tang(Weijing-tang) induced morphological change such as cytoplasmic constriction in the normal cells and the carcinoma cells, but it did not show any strong inhibitory effect on the cell growth. Samso-eum(Shensu-yin) caused severe cell damage in both cell lines, Eunkyo San(Yinqiao-san) significantly damaged the nuclei and caused weak cytoplasmic constriction in both cell lines, Normal cells treated with Gilgyeung-tang(Jingeng-tang) did not show any significant morphological change while some Gilgyeung-tang(Jingeng-tang) treated carcinoma cells were observed to have a normal cell-like shape, interestingly, conclusions : As the results above, Samgibopye-tang(Shenqibufei-tang), Wikyeung-tang(Weijing-tang), and Gilgyeung-tang(Jingeng-tang) helped the growth of both cell lines, and especially Samgibopye-tang(Shenqibufei-tang) showed the best effect, However, Samso-eum(Shensuyin) and Eunkyo-san(Yinqiao-san) caused lethal damage in the normal cells and also showed strong toxicity in the carcinoma cells.