• 한국태양에너지학회 논문집
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• 제26권4호
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• pp.55-61
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• 2006

Titanium oxide ($TiO_2$) films are deposited on the indium tin oxide (ITO) substrate in an $Ar/O_2$ atmosphere by using reactive RF (Radio Frequency) magnetron sputtering technique, and Electrochromic properties and durability of $TiO_2$ films deposited at different preparation conditions are investigated by using UV-VIS spectrophotometer and cyclic voltammetry Li+ interalation/deintercalation in $TiO_2$ films shows that the electrochromic properties and durability of as-deposited films strongly depend on gas pressure $TiO_2$ films formed in our sputtering conditions are found to remain transparent, irrespective of their Li+ ion contents. The optimum sputtering conditions for film as passive counter electrode in electrochromic devices are working pressure of $1.0\;{\times}\;10^{-2}\;torr$ and oxygen flow raes of $10{\sim}15\;sccm$, respectively.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1860-1865
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• 2019

The confinement degradation of the energetic particles during RMP would be a key issue in success of realizing the successful energy production using fusion plasma, because a 3.5 MeV energetic alpha particle should be able to sustain the burning plasma after the ignition. As KSTAR recent results indicate the generation of high-performance plasma(${\beta}_p{\sim}3$), the confinement of the energetic particles is also an important key aspect in neutral beam driven plasma. In general, the measured absolute value of the neutron intensity is generally used for to estimating the confinement time of energetic particles by comparing it with the theoretical value based on transport calculations. However, the availability of, but for its calculation process, many accurate diagnostic data of plasma parameters such as thermal and incident fast ion density, are essential to the calculation process. In this paper, the time evolution of the neutron signal from an He3 counter during the beam blank has permitted to facilitate the estimation of the slowing down time of energetic particles and the method is applied to investigate the fast ion effect on ELM suppressed KSTAR plasma which is heated by high energy deuterium neutral beams.

• Bulletin of the Korean Chemical Society
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• 제15권6호
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• pp.424-427
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• 1994

Effects of iron compounds in known biomimetic oxidation systems (Gif IV and GoAgg II) have been studied on activity and ketone/alcohol selectivity of cyclohexane oxidation. Both ketone/alcohol ratio and cyclohexane conversion were affected by counter-ion Z of iron compounds Z-Fe. When Z has a more electron withdrawing property, the reactivity is increased and the formation of ketone is favored. From these experimental results, a new mechanism is proposed for the biomimetic oxidation system.

• 대한화학회지
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• 제34권1호
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• pp.44-50
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• 1990

페놀류의 구조 이성질체의 액체 크로마토그래피적 머무름거동을 이동상의 성질을 변화시켜 조사했다. 역상 액체 크로마토그래피에서 페놀류의 구조이성질체에 대한 머무름거동은 첨가한 용리액의 전해질에 영향을 받았다. 이 머무름거동은 Langmuir의 흡착등온선과 페놀이온과 전해질 이온으로 코우팅 된 정지상 사이의 이온교환과정으로 설명할 수 있다. 이 거동은 전해질의 농도에 따라 두 영역으로 나누어져서 반대이온효과가 나타나는 부분과 동종이온효과가 나타나는 부분으로 설명할 수 있다. 머무름값이 극대가 나타나는 것은 유기용매의 종류에는 관계없이 전해질의 종류와 농도에 따라 다르게 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 춘계학술대회 논문집
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• pp.86-90
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• 1992

We have studied the characteristics of n-and p-channel FETs with submicron channel length fabricated by twin-well process. Threshold voltage variation and potential distribution with channel ion implantation conditions and impurity profile of n-and p-channel region wee simulated using SUPREM-II and MINIMOS 4.0 simulater, P-channel FET had buried-channel in the depth of 0.15 $\mu\textrm{m}$ from surface by counter-doped boron ion implantation for threshold voltage adjustment. As a result of device measurement, we have obtained good drain saturation characteristics for 3.3 [V] opreation, minimized short channel effect with threshold voltage shift below 0.2[V], high punchthrough and breakdown voltage above 10[V] and low subthreshold value.

• 한국환경과학회지
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• 제14권2호
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• pp.241-249
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• 2005

This study deals with micellar effects on dephosphorylation of diphenyl-4- nitrophenylphosphate (DPNPPH), diphenyl-4-nitrophenylphosphinate (DPNPlN) and isopropylphenyl-4-nitrophenyl phosphinate (IPNPlN) mediated by $OH^\Theta$ or o-iodosobenzoate ion $(IB^\Theta)$ in aqueous and CTAX solutions. Dephosphorylation of DPNPPH, DPNPIN and IPNPIN mediated by $OH^\Theta$ or o-iodosobenzoate ion $(IB^\Theta)$ is relatively slow in aqueous solution. The reactions in CTAX micellar solutions are, however, much accelerated because CTAX micelles can accommodate both reactants in their Stem layer in which they can easily react, while hydrophilic $OH^\Theta\;(or\;IB^\Theta)$ and hydrophobic substrates are not mixed in water. Even though the concentrations $(>10^{-3}\;M)\;of\;OH^\Theta\;(or\;IB^\Theta)$ in CTAX solutions are much larger amounts than those $(6\times10^{-6}\;M)$ of substrates, the rate constants of the dephosphorylations are largely influenced by the change of concentration of the ions, which means that the reactions are not followed by the pseudo first order kinetics. In comparison to effect of the counter ions of CTAX in the reactions, CTACI is more effective on the dephosphorylation of substrates than CTABr due to easier expelling of $Cl^\Theta$ ion by $OH^\Theta\;(or\;IB^\Theta)$ ion from the micelle, because of easier solvation of $Cl^\Theta$ ion by water molecules. The reactivity of IPNPlN with $OH^\Theta\;(or\;IB^\Theta)$ is lower than that of DPNPlN. The reason seems that the 'bulky' isopropyl group of IPNPIN hinders the attack of the nucleophiles.

• 대한화학회지
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• 제38권10호
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• pp.753-762
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• 1994

OH-이온이나 o-iodosobenzoate 이온($IB^-$)에 의한 diphenyl- 및 isopropylphenyl-4-nitrophenylphosphinate (DPNPIN or IPNPIN)의 탈인산화반응은 비교적 느리나, CTAX 미셀용액속에서는 매우 촉진된다. 그 이유는 수용액속에서는 친수성인 $OH^-$(또는 $IB^-$)와 소수성인 포스피네이트가 서로 섞일 수 없으나 CTABr 및 CTACl 미셀은 이들 양쪽을 모두 수용할 수 있기 때문이다. 이때 유사 1차속도상수는 미셀의 농도가 증가함에 따라 증가하다가 최대에 이르고 다시 서서히 감소한다. 또한, 기질인 포스피네이트들의 농도가 증가함에 따라 증가하다가 최대에 이르고 다시 서서히 감소한다. 또한, 기질인 포스피네이트들의 농도($6.0{\times}10^{-6}$ M)보다 $OH^-$ 또는 $IB^-$ 등의 친핵체의 농도(> $10^{-3}$ M)가 과량으로 사용되었기 때문에 이들 반응은 유사 1차 반응속도식(kinetics)을 따를 것으로 예상하였으나, 실제 이들 친핵체의 농도의 영향을 받고 있다. 한편, CTABr 용액속에서의 반응과 CTACl 용액속에서의 반응은 같은 모양으로 진행되나, CTACl 용액속에서의 반응이 훨씬 빠르다. 이것은 다 같은 $CTA^+$ 양이온성 미셀이지만, 반대 이온(counter ion)인 $Br^-$과 $Cl^-$의 $OH^-$(또는 $IB^-$)와의 교환 능력의 차이 때문이다. 즉 수화 능력이 큰 $Cl^-$이온이 물층으로 더 쉽게 이행되고, 그로 말미암아 더 많은 $OH^-$(또는 $IB^-$)가 미셀속으로 들어가게 되어 포스피네이트와 더 많이 반응하게 된다. 두 포스포네이트의 탈인산화반응은 DPNPIN이 IPNPIN보다 훨씬 빠르다. 이것은 phenyl기가 덩치가 큰 isopropyl기보다 반응 전이상태에서 입체장해를 덜 주기 때문인 것으로 판단된다. 그리고 IPNPIN의 탈인산화반응에서 $IB^-$이온이 일반염기로 작용하는지 친핵체로 작용하는지를 밝히고자 반응 생성물인 p-nitrophenoxide 이온을 외부에서 가해서 반응속도의 감소 효과를 관찰함으로써, 이 반응이 친핵체의 공격에 의해 진행됨을 밝혔다. 이와 같은 함정 실험(trapping experiment)은 매우 느린 수용액에서의 반응에 비해, 본 연구에서와 같이, 미셀 용액속에서의 빠른 반응에 더욱 효과적이라 판단된다. 아울러 반응속도론적 동위원소효과(kinetic isotope effect)도 관찰하였다.

• Korea-Australia Rheology Journal
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• 제17권4호
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• pp.157-164
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• 2005

Hydrodynamic characteristic of surfactant drag-reducing flows is still not fully understood. This work investigated the temperature and diameter effect on hydrodynamic characteristic of cationic surfactant drag reducing flows in pipes. Solution of oleyl bishydroxyethyl methyl ammonium chloride (Ethoquad O/12), 900 ppm, as a cationic surfactant and sodium salicylate (NaSal), 540 ppm, as a counter-ion was tested at 12, 25, 40, and $50^{\circ}C$ in pipes with diameter of 13, 25, and 40 mm. Drag reduction effectiveness of this surfactant solution was evaluated in 25 mm pipe from 6 to $75^{\circ}C$. Rheological characteristic of this solution was measured by stress control type rheometer with cone-and-plate geometry. Scale-up laws proposed by previous investigators were used to evaluate the flow characteristic of the solution. It was found that this surfactant solution has clear DR capability until $70^{\circ}C$. Result of this work suggested that temperature has a significant influence in changing the hydrodynamic entrance length of surfactant drag reducing flows. From rheological measurement, it was found that the solution exhibits Shear Induced Structure at all temperatures with different degree of peak viscosity and critical shear rate.

• 폴리머
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• 제25권5호
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• pp.671-678
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• 2001

Sodium 또는 zinc로 중화된 poly(ethylene-co-methacrylic acid)의 아이오노머는 ethylene 사슬 부분들로만 이루어진 결정상, acid 그룹이 존재하는 amorphous 영역, 그리고 ionic aggregate의 세 가지 상으로 나누어진다. Soaking에 의하여 흡수된 nonionic dye 분자들은 결정상을 제외한 amorphous 부분이나 ionic aggregate 분근에 존재하는데, 주위 사슬의 극성에 따라 dispersion force (ethylene 사슬 부분), polar force (acid 부분), ionic dipole (ionic aggregate 부분)의 세 가지 다른 힘의 영향 아래 놓이게 된다. 극성이 적은 ethylene 사슬부분의 dispersion force 영향 아래에 존재하는 Nile Red의 UV/Vis 흡수피크는 500nm 부근에서, polar한 acid 그룹의 영향을 받는 dye 피크는 525 nm, 그리고 ionic aggregate의 영향에 의한 dye는 Na+-아이오노머의 경우 550 nm, divalent이어서 더 큰 ionic dipole을 가지는 $Zn^{2+}$-아이오노머의 경우 610nm에서 각각 피크가 나타났다.

• 대한약리학회지
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• 제26권1호
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• pp.35-49
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• 1990

A highly purified $(Na^+,\;K^+)-ATPase$ from the rectal gland of Squalus acanthias and from the electric organ of Electrophorus electricus has been used to raise antibodies in rabbits. The 97,000 dalton catalytic subunit and glycoprotein derived from the rectal gland of spiny shark were also used as antigens. The two $(Na^+,\;K^+)-ATPase$ holoenzymes and the two shark subunits were antigenic. In Ouchterlony double diffusion experiments, these antibodies formed precipitation bands with their antigens. Antibodies prepared against the two subunits of shark holoenzyme also formed precipitation bands with their antigens and shark holoenzyme, but not with eel holoenzyme. These observations are in good agreement with inhibitory effect of these antibodies on the catalytic activity of $(Na^+,\;K^+)-ATPase$ both from the shark and the eel, since there is very little cross-reaction between the shark anticatalytic subunit antibodies and the eel holoenzyme. The maximum antibodies titer of the anticatalytic subunit antibodies is found to be 6 weeks after the initial single exposure to this antigen. Multiple injections of the antigen increased the antibody titer. However, the time required to produce the maximum antibody titer was approximately the same. These antibodies also inhibit catalytic activity of $(Na^+,\;K^+)-ATPase$ vesicles reconstituted by a slow dialysis of cholate after solubilization of the enzyme in a presonicated mixture of cholate and phospholipid. In these reconstituted $(Na^+,\;K^+)-ATPase$ vesicles, effects of these antibodies on the fluxes of $Na^+$, $Rb^+$, and $K^+$ were investigated. Control or preimmune serum had no effect on the influx of $^{22}Na^+$ or the efflux of $^{86}Rb^+$. Immunized sera against the shark $(Na^+,\;K^+)-ATPase$ holoenzyme, its glycoprotein or catalytic subunit did inhibit the influx of $^{22}Na^+$ and the efflux of $^{86}Rb^+$. It was also demonstrated that these antibodies inhibit the coupled counter-transport of $Na^+$ and $K^+$ as studied by means of dual labeling experiments. However, this inhibitory effect of the antibodies on transport of ions in the $(Na^+,\;K^+)-ATPase$ vesicles is manifested only on the portion of energy and temperature dependent alkali metal fluxes, not on the portion of ATP and ouabain insensitive ion movement. Simultaneous determination of effects of the antibodies on ion fluxes and vesicular catalytic activity indicates that an inhibition of active ion transport in reconstituted $(Na^+,\;K^+)-ATPase$ vesicles appears to be due to the inhibitory action of the antibodies on the enzymatic activity of $(Na^+,\;K^+)-ATPase$ molecules incorporated in the vesicles. These findings that the inhibitory effects of the antibodies specific to $(Na^+,\;K^+)-ATPase$ or to its subunits on ATP and temperature sensitive monovalent cation transport in parallel with the inhibitory effect of vesicular catalytic activity by these antibodies provide direct evidence that $(Na^+,\;K^+)-ATPase$ is the molecular machinery of active cation transport in this reconstituted $(Na^+,\;K^+)-ATPase$ vesicular system.