• Journal of the Korean Vacuum Society
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• v.3 no.4
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• pp.449-456
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• 1994

산업용 주요 냉간금형 소재인 STD 11 강에 질소이온주입하여 이온조입조거에 따른 질화물형성 거동, 경도 및 내마모성 변화에 관해 연구하였다. XRD분석결과 90keV 에너지로 5$\times$1017 ions/cm2 조사 량 이상에서 Fe2N형태의 질화물이 형성되었으며 3$\times$1016 ions/cm2 범위의 모든 조사량에서 경도 및 조 사량에서 경도 및 내마모성 향상효과를 얻었다. Al2O3와의 ball-on-disc 마모거동 분석결과 STD 11모재 는 응착마모와 산화마모의 혼합형태로 마모되는 반면 질소이온주입한 경우 산화마모 경향이 강하게 나 타났다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.255-258
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• 2004

In order to provide a useful data for combustion chamber design, a numerical analysis for spray combustion of liquid fuel and oxidizer in combustion chamber has been conducted. High temperature nitrogen gas in low speed has been conveyed for the ignition of the liquid fuel and oxidizer mixture. Temperature and velocity distributions affected by characteristics of liquid fuel and oxidizer combustion have been investigated.

• Journal of the Korean Vacuum Society
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• v.3 no.3
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• pp.322-330
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• 1994

다결정실리콘 위에 저압 화학 증착법으로 비정질 WSix를 증착시킨 후에 질소 분위기, 87$0^{\circ}C$ 온 도에서 2시간 동안 열처리를 실시하여 결정화를 이룩한 다음 표면의 산화막을 희석된 불산용액으로 제 거한 후 산화를 실시하면 이상산화막이 형성이 되었다. 이와 같은 이상산화막 형성은 산화 공정전에 P 또는 As 이온 주입을 실시함으로써 억제되고 있었으며 P이온 주입 처리가 As 이온조입보다 이상산화 막 발생 억제에 보다 효율적임이 확인되었다. P이온 주입처리가 보다 효과적인 것은 산화시 산화막내에 형성되는 P2O5 가 산화막의 용융점을 크게 낮추어 양질의 산화막을 형성하는 데 기인하는 것으로 여겨 진다. 마지막으로 이온주입 처리에 의하여 비정질화된 텅스텐 실리사이드 표묘의 산화 기구에 대하여 제안하였다.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.487-494
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• 2017

Since nitrate nitrogen is quite stable in aqueous solution, considerable skill is required to remove it. Low concentrations of nitrate nitrogen are easily removed, while high concentrations of nitrate nitrogen are difficult to remove. This study is to show that nitrate nitrogen in the form of gaseous nitrogen can be removed by using zinc ball with a diameter of about 3mm and to test the removal characteristics of nitrate nitrogen under various reaction conditions. As a result of this study, the treatment efficiency of nitrate nitrogen by continuous treatment with zinc ball was about 80%. However, there is a problem that the wastewater must be maintained in an acidic atmosphere of about pH 2, and the treated wastewater must be neutralized and discharged.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.190-196
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• 2007

This study examined the nitrate removal efficiency which uses an electrowinning, and also analyzed the nitrate removal efficiency under a variety of operating conditions such as nitrate concentrations, pH, current densities, electrodes, reducing agents in order to determine optimal conditions. In addition, the multi-step electro-chemical process test has been also analyzed. During the electrowinning, the identical Zn-Zn and Pt-Ti electrodes in the insoluble oxidation electrode(Pt) has shown the highest nitrate removal efficiency in the 100 mg $NO_3^{-}$ -N/L concentration. In the concentration of 150 mg $NO_3^{-}$ -N/L, the efficiency of the Zn-Zn electrode were 70~85%, and that of Pt-Ti electrode were 40~50% without any change of pH. In the high concentration of 500 and 1,000 mg $NO_3^{-}$ -N/L, the higher the concentration, the more decrease of its nitrate removal efficiency decreased. However, the energy consumed for nitrogen removal increased when the nitrate concentration was high. As a result of the multi-step electro-chemical process test, We chose the Test 4. Because the first, most of the zinc consumed from 1 step was recovered from over the 2 step. The second, amount of consumption anode decreased with insoluble anode Pt from over the 2 step. And the third, Zn cathode increased the possibility of reusing Zn deposited. In view of the results so far achieved, the multi-step electro-chemical process would be applied to treat nitrogen involved in metal finishing wastewater.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.471-475
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• 1999

The metal plasma-etch damage immunity of nMOSFET with $N{_2}O$ gate oxide is found to be improved comparing to that with regular pure oxide of similar thickness. With increasing the antenna ratio (AR), the characteristics of nMOSFETs with $N{_2}O$ oxide shows tighter initial distribution and smaller degradation under constant field stress, which is explained by the effect of the nitrogen at the substrate $Si/SiO_2$ interface. Also, if $N{_2}O$ gate oxide is used, the maximum allowable size of metal AAR and PAR may be increased to the much larger values. These improvements of nMOSFETs with $N{_2}O$ gate oxide are attributed to the effect of the interface hardness improved by the nitrogen included at the substrate-Si/$N{_2}O$-oxide interface.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.05a
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• pp.55-58
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• 1997

대기오염의 주요원인은 소각로 연소가스와 자동차의 배기가스로 이들 이동 오염원에서 배출되는 오염가스는 일산화탄소, 탄화수소, 질소 및 황산화물 둥이고 이들은 공기중의 산소와 반응하여 광화학반응을하여 오존을 생성하며 기타 미세먼지, 수분과 반응하여 스모그를 생성하여 인체의 호흡기 계통 질병을 유발케한다. (중략)

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.172-183
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• 1999

Background: Nitric oxide is a short-lived effector molecule derived from L-arginine by the nitric oxide synthase(NOS). Nitric oxide plays a role in a number of physiologic and pathophysiologic functions including host defense, edema formation, and regulation of smooth muscle tone. Some kinds of cells including macrophage are known to produce large quantities of nitric oxide in response to inflammatory stimuli such as interleukin-$1\beta$(IL-$1\beta$), tumor necrosis factor-$\alpha$(TNF-$\alpha$), interferon-$\gamma$(IFN-$\gamma$) and lipopolysaccharide(LPS). Reactive oxygen species are also known to be important in the pathogenesis of acute cell and tissue injury such as acute lung injury model Methods: Using the RA W264.7 cells, we have examined the ability of oxidant hydrogen peroxide($H_2O_2$) to stimulate nitric oxide production and inducible NOS mRNA expression. Also, we have examined the effects of NOS inhibitors and antioxidants on $H_2O_2$ induced nitric oxide production. Results: Stimulation of RAW264.7 cells with combinations of 100 ng/ml IL-$1\beta$, 100 ng/ml TNF-$\alpha$, and 100 U/ml IFN-$\gamma$ or 100 U/ml IFN-$\gamma$ and $1{\mu}g/ml$ LPS induced the synthesis of nitric oxide as measured by the oxidation products nitrite($NO_2^-$) and nitrate($NO_3^-$). Addition of $250 {\mu}M-2$ mM $H_2O_2$ to the cytokines significantly augmented the synthesis of $NO_2^-$ and $NO_3^-$(p<0.05). When cells were incubated with increasing concentrations of $H_2O_2$ in the presence of IL-$1\beta$, TNF-$\alpha$ and IFN-$\gamma$ at constant level, the synthesis of $NO_2^-$ and $NO_3^-$ was dose-dependently increased(p<0.05). $N^G$-nitro-L-arginine methyl ester(L-NAME), dose dependently, significantly inhibited the formation of $NO_2^-$ and $NO_3^-$ in cells stimulated with LPS, IFN-$\gamma$ and $H_2O_2$ at constant level(p<0.05). Catalase significantly inhibited the $H_2O_2$-induced augmentation of cytokine-induced $NO_2^-$ and $NO_3^-$ formation(p<0.05). But, boiled catalase did not produce a significant inhibition in comparison with the native enzyme. Another antioxidant 2-mercaptoethanol and orthophenanthroline dose-dependently suppressed $NO_2^-$ and $NO_3^-$ synthesis(p<0.05). Northern blotting demonstrated that H:02 synergistically stimulated the cytokine-induced iNOS mRNA expression in RA W264.7. Conclusion: These results suggest that $H_2O_2$ contributes to inflammatory process by augmenting the iNOS expression and nitric oxide synthesis induced by cytokines.

• Journal of Life Science
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• v.19 no.5
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• pp.625-632
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• 2009

The purpose of this study was to examine the effect of exercise training on nitric oxide (NO) levels, mean arterial pressure (MAP), blood pressure (BP), and heart rate (HR) in college students. 5 subjects were randomly assigned to two experimental groups; an aerobic training group (ATG) and a resistance training group (RTG). In aerobic training, based on measured maximum oxygen consumption rate, 70% exercise intensity was applied and conducted for 60 min. In resistance training, 70% of 1-RM was performed for 90 min. Blood sampling was conducted 3 times during resting state, post-exercise, and after 30 minutes of recovery. The results are as followed. For the post training values of $VO_2max$, % body fat and MAP, there were significant differences in the ATG compared to pre training (p<0.05). However, there were no differences in the RTG between pre and post training. NO increased post training, during rest and at the end of exercise compared to pre training in the ATG (p<0.05). Also, the HR decreased in post training at the end of exercise (p<0.05), however, there were no significant differences in SBP and DBP between pre and post training in the ATG. The HR, SBP and DBP did not change at all in post training compared to pre training in the RTG. In conclusion, an increase in the production of Nitric Oxide (NO) concentration and $VO_2max$, decrease of body fat% and physiological variables (HR, BP, MAP) were shown to be more effective in aerobic training (AT) than resistance training (RT).

• Journal of Life Science
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• v.24 no.10
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• pp.1137-1143
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• 2014

Doxorubicin is a general chemotherapy drug widely used for a number of cancers. However, the correlation between endogenous nitric oxide ($NO^{\bullet}$) levels and chemoresistance to doxorubicin remains unclear. In this study, we investigated the effect of endogenous $NO^{\bullet}$ on the anticancer activity of doxorubicin in human colon cancer cell lines HCT116 and HT29 with different p53 status. The cells were treated with either doxorubicin alone or in combination with the $NO^{\bullet}$ synthase (NOS) inhibitor $N^G$-monomethyl-L-arginine (NMA). Doxorubicin differentially inhibited the growth of both the HCT116 (p53-WT) and HT29 (p53-MUT) cells, which was mitigated by cotreatment with NMA. Further studies revealed that inhibition of endogenous $NO^{\bullet}$ mitigated doxorubicin-induced apoptosis in the HCT116 and HT29 cells, as evidenced by apoptotic DNA fragmentation and the sub-G1 peak of apoptotic markers. Apoptosis was delayed in the HT29 cells, and its magnitude was greatly reduced, underscoring the importance of the modulation of p53 in the response. RT-PCR analysis revealed that doxorubicin down-regulated levels of inhibitors of the apoptosis family (cellular IAP-1 and-2). Collectively, these data show that induction of apoptosis by doxorubicin in human colon cancer cells is possibly related to modulation of endogenous $NO^{\bullet}$, the expression of the IAP family of genes, and the status of p53. The underlying mechanisms may represent potential targets for adjuvant strategies to improve the efficacy of chemotherapy for colon cancer.