• 전기화학회지
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• 제13권1호
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• pp.45-49
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• 2010

The rechargeable Zn-air battery is considered as one of the potential candidates for the next generation secondary batteries due to its many advantages. However, its further applications and commercialization have been limited by the complexity of the reactions on air electrode which are oxygen reduction and evolution reactions (ORR/OER) upon discharging and charging processes, respectively. In the present study, lanthanum was impregnated into a commercial Pt/C gas diffusion electrode, and it clearly verified significantly enhanced cycling stability and reversibility. The results presented in this study show the possibility of repeated charge/discharge processes for Zn-air batteries with a La-loaded air electrode, and they demonstrate the potential as a promising next generation secondary battery.

• 한국진공학회지
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• 제9권4호
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• pp.428-435
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• 2000

정전 탐침을 이용하여 유도 결합형 반응기에서 발생하는 산소 플라즈마의 음이온 발생 특성을 관찰하였다. 입력전력과 운전압력 조건에 따른 산소 플라즈마에서 electronegative 음이온 플라즈마의 입력전력과 운전압력에 따른 정전 탐침에 흐르는 포화 양 전류 대 포화 음 전류(전자 전류와 음 이온 전류의 합)의 전류 비율과 플라즈마 부유 전위와 플라즈마 전위 차의 변화로부터 음이온 발생 특성관찰을 하였다. 전류비의 증가와 전위차 값의 감소는 입력전력이 증가함에 따라 약 30∼60 mTorr 운전압력 영역에서 나타났으며 이 조건에서 음이온의 발생량이 증가함을 의미하고, 플라즈마내의 이온들은 음이온과 재결합에 의한 손실이 증가하여 플라즈마 밀도가 감소함을 알 수 있었다.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.373-377
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• 2016

Background: Experiments with small electrochemical apparatus were previously carried out for detecting low-energy neutrinos under irradiation of reactor neutrinos and under natural neutrino environment. The experimental result indicated that the output current of reactor-neutrino irradiated detector was appreciably larger than that of natural environmental one. Usual interaction cross-sections of neutrinos are quite small, so that they do not explain the experimental result at all. Materials and Methods: To understand the experimental data, we propose that some biological products may generate AV-type scalar field B0, leading to a large interaction cross-section. The output current generation is ascribed to an electrochemical process that may be assisted by weak interaction phenomena. Dissolved oxygen concentrations in the detector solution were measured in this study, for the purpose of understanding the mechanism of the detector output current generation. Results and Discussion: It was found that the time evolution of experimental output current was mostly reproduced in simulation calculation on the basis of the measured dissolved oxygen concentration. Conclusion: We mostly explained the variation of experimental data by using the electrochemical half-cell analysis model based on the DO concentration that is consistent to the experiment.

• 조명전기설비학회논문지
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• 제29권12호
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• pp.77-82
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• 2015

Ozone is a powerful disinfectant and oxidizing agent, and it is used in a wide range of applications, such as waste water treatment, food processing, etc.. There is also a great potential of using ozone in new emerging medical applications, such as ozone dentistry and ozone oxygen therapy. For these purposes, simple, small, compact and efficient sources of ozone are needed. In this study, in order to increase the current-voltage range of the discharge and to avoid the overheating of the gas in the ozonizer we suggested ozonizer of injection needle and plate electrode type(INP Type) with the gas through the needle. A ozonizer of INP type have been investigated by focusing on ozone concentration and yield according to flow rates and Gap of two electrodes. The results of studies of ozone production for DC corona discharge in oxygen at atmospheric pressure about the ozonizer of INP type. The ozone concentration and the generation yield increased as the gap of two electrodes and gas flow were decreased. Also, when the gap of two electrodes and gas flow with no change, the ozone concentration and generation yield each have variation of direct proportion and inverse proportion with discharge voltage.

• 동의생리병리학회지
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• 제32권3호
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• pp.157-164
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• 2018

This study was designed to investigate the mechanism of the synergistic anticancer effect of Astragalus membranaceus (AM) and Adenophora triphylla var. japonica (AT) in H1299 human lung carcinoma cells. A combined treatment of ethanol extract of AM (EAM) and AT (EAT) explosively increased the reactive oxygen species (ROS) generation in H1299 cells compared to the single treatment of each of them. Co-treatment of N-acetyl-L-cysteine (NAC) with EAM and EAT markedly enhanced the cell viability and suppressed apoptosis in H1299 cells, suggesting that ROS generation contributed to the anticancer effect of EAM and EAT. Interestingly, the combined treatment of EAM and EAT down-regulated p-AKT in H1299 cells, which was abrogated by NAC treatment. These results clearly indicated that ROS generation mediated the inactivation of AKT. Co-treatment of LY294002 with EAM and EAT significantly reduced the cell viability at a concentration which EAM and EAT didn't show any cytotoxicity. In addition, the recovery of cell viability by co-treatment of NAC with EAM and EAT was quite reversed by LY294002 treatment, which confirmed that the inactivation of AKT played a pivotal role in ROS-mediated apoptosis. Taken together, our results demonstrated that the synergistic anticancer effect of EAM and EAT was mediated by ROS generation and inactivation of AKT. We provide a valuable preclinical data for the development of more effective combination of AM and AT to treat lung cancer.

• 한국작물학회지
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• 제33권4호
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• pp.370-374
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• 1988

Clark type의 산소전극장치를 이용하여 기 선발된 oxyfluorfen 및 bensulfuron-methyl 에의 내성 및, 감수성 수도품종에 대한 광합성 및 호흡반응차이를 비교한 목적으로 본 시험이 수행되었다. 결과를 요약하면 다음과 같다. Oxyfluorfen 농도증가로 $O_2$ 발생율은 저하하는 반면에 호흡율은 상승하였다. 벼 풍종간에는 $10^{-3}$M에서 감수성이었던 Mushakdanti 의 광합성율이 무처리의 43%까지 떨어졌으나 내성이었던 Aichiasahi 는 56%까지로서 상대적으로 덜 떨어졌으며 호흡에서의 품종차이는 거의 없었다. Bensulfuron-methyl 농도증가에 따라서 $O_2$ 발생율은 저하(감수성인 IR 1846은 광합성에서 무처리의 55%까지, 내성인 Chinsurah Boro II 는 77%까지만 저하) 하였고 호흡율은 상승(품종간에 140~149% 내외의 차이)하는 양상으로서 역시 내성품종이 광합성에서 덜 떨어지는 반면 호흡에선 품종간 차이가 인정되지 않는 경향이있다.

• 식품저장과 가공산업
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• 제7권1호
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• pp.9-18
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• 2008

The health benefits of garlic (Allium sativum L.) are derived from a wide variety of components and from the different ways it is administered. The known health benefits of garlic include cardiovascular protective effects, stimulation of immune function, reduction of blood glucose level, protection against microbial, viral and fungal infections, as well as anticancer effects. In the present study, it was examined the effects of water extract of A. sativum (WEAS) on the growth of cultured human tumor cells in order to investigate its anti-proliferative mechanism. Treatment of WEAS to tumor cells resulted in the growth inhibition, especially in leukemia cells, which was associated with induction of G2/M arrest of the cell cycle and apoptosis. In order to further explore the critical events leading to apoptosis in WEAS-treated U937 human leukemia cells, the following effects of WEAS on components of the mitochondrial apoptotic pathway were examined: generation of reactive oxygen species (ROS), alteration of the mitochondrial membrane potential (MMP), and the expression changes of Bcl-2 and IAP family proteins. The cytotoxic effect of WEAS was mediated by its induction of apoptosis as characterized by the occurrence of DNA ladders, apoptotic bodies and chromosome condensation in U937 cells. The WEAS-induced apoptosis in U937 cells was correlated with the generation of intracellular ROS, collapse of MMP, activation of caspase-3 and down-regulation of anti-apoptotic proteins. The quenching of ROS generation with antioxidant N-acetyl-L-cysteine conferred significant protection against WEAS-elicited ROS generation, caspase-3 activation, G2/M arrest and apoptosis. In conclusion, the present study reveals that the cellular ROS generation plays a pivotal role in the initiation of WEAS-triggered apoptotic death in U937 cells.

• 생명과학회지
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• 제25권2호
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• pp.231-236
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• 2015

Angiotensin II (AngII)는 혈관평활근세포의 수축을 통해 혈관을 수축시키는 강력한 작용을 나타낼 뿐만 아니라 혈관세포의 성장 등에 중요한 역할을 한다. 본 연구에서는 AngII에 의해 형성되는 활성산소가 phosphatidylinositol 3-kinase (PI3K)에 유리되는 칼슘에 의해 조절된다는 것을 검증하였다. 쥐의 대동맥으로부터 분리된 혈관평활근세포에서 AngII에 의해 활성산소가 농도 의존적, 그리고 시간 의존적으로 형성됨을 관찰하였다. AngII에 의해 형성되는 활성산소는 PI3K의 억제제에 의해 봉쇄되었으나 EKR의 억제제에 의해서는 봉쇄되지 않음을 알 수 있었다. AngII에 의해 유리되는 칼슘은 L-type 칼슘이온통로 봉쇄제인 Nifedipine 또는 배양액에 칼슘이 제거된 환경에서 억제됨을 확인할 수 있었다. 마지막으로 AngII에 의해 형성되는 활성산소는 배양액에 칼슘이 없는 조건이나 L-type 칼슘이온통로 억제제를 전처리 하였을 경우 억제되는 것을 확인하였다. 이러한 결과들을 바탕으로 쥐의 대동맥으로부터 분리된 혈관평활근세포에서 AngII에 의한 활성산소의 형성은 PI3K/L-type 칼슘이온통로를 통한 기전을 통해 조절됨을 제안한다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.508-508
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• 1996

;The growth of films have considerable interest in the field of superlattice structured multi-layer epitaxy led to realization of new devices concepts. Molecular beam epitaxy (MBE) with in situ observation by reflection high-energy electron diffraction (RHEED) is a key technology for controlled layered growth on the atomic scale in oxide crystal thin films. Also, the combination of radical oxygen source and MBE will certainly accelerate the progress of applications of oxides. In this study, the growth process of single crystal films using by MBE method is discussed taking the oxide materials of Bi-Sr-Ca-Cu family. Oxidation was provided by a flux density of activated oxygen (oxygen radicals) from an rf-excited discharge. Generation of oxygen radicals is obtained in a specially designed radical sources with different types (coil and electrode types). Molecular oxygen was introduced into a quartz tube through a variable leak valve with mass flowmeter. Corresponding to the oxygen flow rate, the pressure of the system ranged from $1{\;}{\times}{\;}10^{-6}{\;}Torr{\;}to{\;}5{\;}{\times}{\;}10^{-5}$ Torr. The base pressure was $1{\;}{\times}{\;}10^{-10}$ Torr. The growth of Bi-oxides was achieved by coevaporation of metal elements and oxygen. In this way a Bi-oxide multilayer structure was prepared on a basal-plane MgO or $SrTiO_3$ substrate. The grown films compiled using RHEED patterns during and after the growth. Futher, the exact observation of oxygen radicals with MBE is an important technology for a approach of growth conditions on stoichiometry and perfection on the atomic scale in oxide. The oxidization degree, which is determined and controlled by the number of activated oxygen when using radical sources of two types, are utilized by voltage locked loop (VLL) method. Coil type is suitable for oxygen radical source than electrode type. The relationship between the flux of oxygen radical and the rf power or oxygen partial pressure estimated. The flux of radicals increases as the rf power increases, and indicates to the frequency change having the the value of about $2{\times}10^{14}{\;}atoms{\;}{\cdots}{\;}cm^{-2}{\;}{\cdots}{\;}S^{-I}$ when the oxygen flow rate of 2.0 seem and rf power 150 W.150 W.

• 설비공학논문집
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• 제15권8호
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• pp.697-703
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• 2003

Cogeneration is the simultaneous generation of heat and electricity in a single unit, and is a highly energy-efficient technology compared to the independent generation of both products. Therefore, cogeneration has been widely introduced in many countries for use in industrial, commercial and residential applications. However, there have been few models with an output of less than 100 kilowatt. In the present study, a spark ignited gas engine with electric generation output of 10 kilowatts was developed for micro cogeneration package. The gas engine shows 26.7% of electric generation efficiency, NOx emission less than 10 ppm at 13% oxygen, 82 dB of Noise level, and about 3 seconds of switching time from idling to nominal power.