• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2010.04a
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• pp.193-193
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• 2010

이전의 연구에서 우리는 선응집 기술을 적용한 중질탄산칼슘의 크기에 따른 수초지의 물성을 평가하였다. 이때 선응집 기술이 적용된 충전물의 입도와 분포를 측정하기 위해 light diffraction spectroscopy (LDS) 가 사용되었다. 경질탄산칼슘과 양이온성 고분자의 흡착 현상을 알아보기 위한 이번 연구에도 LDS가 사용되었으며, 일회성으로 입자의 크기와 분포를 측정하는 것에서 더 나아가 시간의 흐름에 따라 응집체의 형성과 파괴, 재성장을 관찰할 수 있는 도구로서 역할 하였다. 본 연구에서 우리는 세 가지 경우로 나누어 경질탄산칼슘의 응집 현상을 관찰하였다. 첫째로 경질탄산칼슘에 흡착되는 양이온성 고분자의 특성, 분자량과 전하밀도, 을 달리하여 응집체의 성장과 파괴를 관찰하였다. 둘째, 양이온성 고분자로 중질탄산칼슘을 응집시켜, 경질탄산칼슘 응집체의 경우와 입도와 전단 안정성 등을 비교하였다. 마지막으로 나노 크기의 실리카 투입이, 마이크로 크기의 경질탄산칼슘 응집체가 강한 전단에 의해 파괴되었을 때, 응집체의 전단 안정성이나 재성장 측면에 도움을 주는지 관찰하였다. 내첨용 충전물로써 경질탄산칼슘의 사용이 전 세계적으로 늘고 있는 시점에서 양이온성 고분자 첨가에 의한 경질탄산칼슘의 응집 현상을 관찰하는 것은 일반적인 제지 공정에서 경질탄산칼슘의 거동을 이해하는데 도움이 될 뿐만 아니라, 내첨용 충전물 첨가에 따른 종이의 강도 저하 방지를 위한 선응집 기술의 적용에도 도움이 될 수 있을 것으로 생각한다.

• Journal of Life Science
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• v.14 no.1
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• pp.17-20
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• 2004

Effects of monovalent cations were examined on the fast $\beta$reaction of $\alpha$D56N and $\alpha$D56G mutant tryptophan synthase. Reaction rates for the production and degradation of intermediates in the reaction were changed in the presence of cathons. The mutant proteins showed different reaction rates from those of wild-type protein, and additional changes occurred in the presence of cations. The results showed that monovalent cations and $\alpha$D56 are important in allosteric properties of this protein.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.138-144
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• 2011

Purpose: The purpose of this study was to evaluate the cleansing effect of recently developed alkaline ionized water, e-WASH, on microorganisms of the denture surface. Materials and methods: Removable partial and complete dentures were randomly assigned to the experimental group of 41 dentures, and the control group of 26. The denture was immersed in the e-WASH solution (experimental group), or tap water (control group) for 5 minutes. The plaque was collected from the denture surface before and after immersion, and smeared on the slide glass. Amount and motility of microorganisms were compared according to the morphology and strain of microorganisms, using the phase contrast microscope. Statistical analysis was accomplished with paired t-test and independent t-test at 95% confidence level (P<.05). Results: 1. The amount of cocci, bacilli, filamentous, spiral/comma, and the motility of bacilli, filamentous, and spiral/comma were decreased after denture cleansing with the alkaline ionized water, e-WASH (P<.05). But in the control group, only the amount of cocci showed a significant difference (P<.05), but no difference from the others. There were no differences in other analysis. 2. In the experimental group, the amount of cocci, bacilli, filamentous, spiral/comma, and the motility of bacilli, filamentous, and spiral/comma were smaller and more inactive compared to the control group (P<.05). Conclusion: These results indicated that the alkaline ionized water, e-WASH could effectively reduce the amount and motility of the experimented microorganisms on the denture surface, and that e-WASH could be recommended as an effective denture cleanser.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.633-638
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• 2016

In this study, we used three kinds of commercially available cation, anion, and mixed-ion exchange resins to separate radioactive ions from a polluted water containing Cs, I, and other radioactive ions. The experiment was conducted at a room temperature with a batch method, and a comparative analysis on the decontamination ability of each resin for the removal of Cs and I was performed by using different quantities of resins. The concentration was analyzed using ion chromatography and the ion exchange resin product from company D showed an overall high ion exchange ability. However, for most of the experiments when the amount of ion exchange resin was decreased, the decontamination ability of the resins against mass increased. When the mass of company D's cation exchange resin was small, the ion exchange ability against Cs and I ions were measured as 0.199 and 0.344 meq/g, respectively. When the mixed ion exchange resin was used, the ion exchange ability against I ions was measured as 0.33 meq/g. All in all, company D's ion exchange resins exhibited a relatively higher ion exchange ability particularly against I ions than that of other companies' exchange ions.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.219-219
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• 1999

플라즈마 이온 주입은 진공 chamber 내에 주입하려는 이온이 포함된 플라즈마를 발생시킨 후 처리하고자 하는 시편에 negative high voltage pulse를 인가함으로써 시편 주위에 형성되어 있는 이온들을 시편에 주입하는 방법이다. 이러한 플라즈마 이온 주입 방법은 금속의 내마모성, 내부식성, 강도 및 경도를 증가시키고, 고분자 화합물의 표면 개질에 있어서 친수성 또는 소수성과 같은 표면 처리를 쉽고 간단하게 처리할 수 있다. 그리고 반도체 공정의 shallow junction doping을 효과적으로 처리할 수 있으며 특히, 대면적의 시편에 균일하게 이온을 주입할 수 있다. 플라즈마 이온 주입 방법에서 중요한 요소는 dose, 즉 이온 주입한 양과 처리하려는 시편에 주입되는 이온의 에너지이다. 여기서, 플라즈마내에 생성된 이온들의 비율을 정확히 안다면 시편에 주입되는 이온의 양과 주입되는 이온의 에너지를 충분히 예견할 수 있다. 질소 플라즈마의 경우에는 N+와 N2+가 생성되므로, 시편에 주입된 질소 이온의 실질적인 이온당 질소 원자수는 1$\times$N+% + 2$\times$N+%가 되고, N2+의 경우는 N+ 주입 에너지의 1/2 로 시편내에 주입되게 된다. 또한 질소 플라즈마의 경우 N2+ 이온이 상대적으로 N+이온보다 많다면 N+가 많은 경우보다 이온 주입 깊이는 얕아지게 된다. 본 실험에서는 Dycor M-100 residual gas analyzer와 potical emission spectrometer (Ocean Optics SQ 2000)를 사용하여 압력과 RF power를 변화시키며 플라즈마내에 생성되어지는 질소 이온의 비율을 측정하였다. 또한 Langmuir probe를 이용하여 속도차에 의한 각 이온들의 존재비율을 계산하였다. 여기에서 질소 가스의 압력이 낮을수록 N+보다 N2+의 존재비율이 높음을 보였다. 이것은 압력이 낮은 영역에서 일반적으로 전자의 평균온도가 높기 때문으로 여겨진다.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.694-699
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• 2012

To examine the EC model in a culture medium, basic culture medium of Rush (2005) and EC model of Robinson and Strokes (1959) were applied analyzing the equivalence ion total amount, the EC variable of cation and anion. Following the experiential translation by Steiner (1980), 130 optimized domestic and foreign culture media for crop growth were utilized, and estimated EC model was also demonstrated. Results from basic culture medium of Rush (2005) suggests an estimated EC by equivalence ion total amount and high reliable regressive model with 0.96 y = 1.33x - 0.23 of 0.96 as value $R^2$. It was found out that the change in concentration of positive ion and anion did not differ significantly with the increase and decrease of EC, however, there occurred a slight variable range. The change brings about a bigger anion influence than the previously reported positive ion, seemingly like those based on nitride ion and sulfur ion. The above EC estimated models confirmed that with optimized 130 domestic and foreign culture media for crop growth, the value derived will be as follows: $R^2$ = 0.98 with y = 1.23x - 0.02. In addition, the contour analysis of positive ion and anion for EC, with popularly known concentration range of EC $1.5-2.5dS{\cdot}m^{-1}$ reveals an equivalent of more than $11meq{\cdot}L^{-1}$ for positive ion and $15meq{\cdot}L^{-1}$ for anion. On the other hand, the left bottom, low concentration $1.5dS{\cdot}m^{-1}$ and the right above, high concentration $2.5dS{\cdot}m^{-1}$, for both positive ion and anion existed differently in a proper culture medium concentration. This study adapted variables of both positive ion and anion of EC simultaneously, unlike in the previous culture medium by ion ratio in mutual ratio of Steiner (1980), and offers an EC model that can estimate levels or positive ion and anion in proper concentration, EC $1.5-2.5dS{\cdot}m^{-1}$, with distributed features of ions.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.1-5
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• 2006

The crystallographic properties and cation distribution of oxyspinels ferrite $Co_xFe_{1-x}O_4$ thin films have been explored by X-ray diffraction, vibrating sample magnetometer (VSM), and conversion electron $M\"{o}ssbauer$ spectroscopy (CEMS). Thin films are prepared by sol-gel method. Normal spinel structure is transformed to inverse spinel structure with increasing Co concentration CEMS results indicate that most of $Fe^{3+}$ ions are substituted to $Co^{3+}$ions. Accordingly $Co^{2+}$ ions on octahedral site migrate to tetrahedral site. Magnetic moment is decreased with increasing Co concentration, which means high spin $Fe^{3+}$ ions are replaced by low spin $Co^{3+}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.192.1-192.1
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• 2013

본 연구는 기존의 Sputtering 방식에 Modulation 방식을 적용한 Modulated Sputtering System (MSS)에 관한 특성 관찰과 이를 이용한 박막 증착 및 분석에 관한 내용이다. MSS에 인가하는 전압은 pulse on 시간동안 타겟에 음의 전압이 인가되어 sputtering에 의한 박막이 증착되고, pulse off 시간동안에는 양의 전압을 인가하여 증착된 박막에 양이온을 입사시켜 에너지 전달에 의한 박막의 특성을 향상시키고 자한다. MSS에 인가되는 전압과 주파수, 그리고 펄스폭을 변화시키며 전압과 전류, 그리고 기판에 입사하는 이온에너지 특성을 관찰하였다. 또한 MSS를 이용하여 티타늄(Ti), 탄소(C), 알루미늄이 도핑된 산화아연(AZO) 박막을 증착하였다. 증착된 박막은 a-step, SEM, XRD, AFM, 4 point probe를 이용하여 박막의 두께, 결정성장면, 표면 거칠기, 비저항 등을 분석하였다. Ti 박막에서는 기판에 입사되는 양이온의 에너지가 증가함에 따라 결정 방위면이 (002)에서 (001)로 변화함을 확인하였고 탄소 박막과 AZO 박막의 경우에는 기판에 입사되는 양이온의 에너지 변화에 따라 박막의 전도도를 조절할 수 있음을 확인하였다.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.593-597
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• 2015

Tricyclopentadiene (TCPD) as a next generation high density fuel was synthesized by Diels-Alder oligomerization reaction of DCPD. TCPD was prepared by ionic liquid (IL) catalysts with combination of cationic and anionic precursors. Two kinds of anionic precursors such as copper(I) chloride (CuCl) and iron(III) chloride ($FeCl_3$) and cationic precursors such as triethylamine hydrochloride (TEAC) and 1-butyl-3-methylimidazolium chloride (BMIC) were used. The preparation of TCPD using IL catalyst was superior to that using Diels-Alder reaction in terms of DCPD conversion and TCPD yield. In addition, TCPD yield was correlated with Lewis acidity by changing the ratio of anionic and cationic precursors. The TCPD yield was higher when using CuCl as anionic precursor than that of using $FeCl_3$. Control of Lewis acidity by changing the molar ratio of anionic and cationic precursors could further improve TCPD yield as well.

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.127-132
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• 1983

The catalytic activity of ZSM-5 catalyst for the disproportionation of toluene is dependent on the type of cation exchanged, the degree of ion-exchange and the reaction temperature. The activity increases in the order of alkaline-, alkali earth-, hydrogen, and rare-earth-exchanged ZSM-5 and decreases with increasing degree of cation exchange. Among the ion-exchanged ZSM-5 catalyst, only Cs-ZSM-5 shows predominant selectivity for p-xylene. The selectivity increases with increasing degree of $Cs^+$-exchange and decreasing reaction temperature. This phenomenon is interpreted in terms of shape selectivity arising from the partial blocking of channel intersections by large cesium ions.