• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.381.2-381.2
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• 2014

In this study the amorphous carbon films were deposited by PECVD at the substrate temperature range of 250 to $600^{\circ}C$, and the process conditions of higher and lower precursor flow rate, respectively. The temperature was a main parameter to control the density and mirco-structures of carbon films, and their's properties depended with the process temperatrue are changed by controlling precursor flow rate. The precursor feeding rate affect on the plasma ion density and a deposition reactivity. This change of film properties was obtained the instrinsic stress, FT-IR & Raman analysis, refractive index (RI) and ext. coef. (k) measured by ellipsometer. In the process conditions of lower and higher flow rate of precursor it had a different intrinsic stress as a function of the substrate temperature.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.504-507
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• 2002

We investigated electro-optic and ionic properties of twisted nematic cells by using control of chiral pitch. These properties are observed in practical experiment and simulations. C-V and V-T curve characteristics were obtained from three types of cells with d/p. It is shown that d/p ratio of short cells exhibit faster response time improved by 20% than normal cell. Also, inter-gray response time is improved each rise time and decay time. And, the increase of saturation voltage is happened because of the small twist angel change from initial state at high voltage near 5V. To compensate for longer black level tail, gamma curve index was varied from g = 2.2 to g = 2.7 in module status. Additionally, adding chiral dopant into TN cells improved ionic characteristics such as increasing VHR, Ion density and DC Hysteresis were decreased..

• 한국표면공학회지
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• 제29권6호
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• pp.788-796
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• 1996

$TiO_2$ films prepared by RF magnetron sputtering, electron beam evaporation, ion assisted deposition (IAD) and sol-gel method are prepared on c-Si substrate and vitreous silica substrate respectively. From the transmission spectra of $TiO_2$ films on vitreous silica substrate in the spectral region from 190 nm to 900 nm, k($\lambda$) of $TiO_2$ is obtained. Using k($\lambda$) in the interband transition region the coefficients of the quantum mechanical dispersion relation of an amorphous $TiO_2$ and hence n($\lambda$) including the optically opaque region of above fundamental transition energy are obtained. The spectroscopic ellipsometry spectra of $TiO_2$ films in the spectral region of 1.5-5.0eV are model analyzed to get the film packing density variation versus i) substrate material, ii) film thickness and iii) film growth technique. The complex refractive index change of these $TiO_2$ films versus water condensation is also studied. Film micro-structures by SE modelling results are compared with those by atomic force microscopy images and X-ray diffraction data.

• 한국광학회지
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• 제9권2호
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• pp.70-75
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• 1998

동시증착법을 이용하여 ZnS와 SiO$_{2}$를 증착시켜 혼합 박막을 제작하고, 제작된 ZnS-SiO$_{2}$ 혼합 박막의 광학적 특성과 결정구조를 분석하였다. 혼합 박막의 Zn:Si의 원소조성비에 따른 광학적 특성은 Drude 모델을 잘 만족함을 알 수 있었다. 이러한 혼합 박막의 굴절률 특성을 이용하여 단층의 무반사코팅을 설계.제작하였다. 한편, 이온 보조 증착하지 않은 혼합 박막은 비정질 구조를 보였으며, 이온 보조 증착한 혼합 박막은 Zn의 함유량이 43.0%, 56.6%일 때 결정질 구조를 보였다.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 제4회 하계분리막 Workshop (초순수 제조와 막분리 공정)
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• pp.121-147
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• 1996

Since 1980, the water quality of ultra-pure water has been rapidly improved, and presently ultra-pore water producing equipment for 64Mbit is in operation. Table 1 shows the degree of integration of DRM and required water quality exlmple. The requirements of the ultra-pure water for 64Mbit are resistivity: 18.2 MQ/cm or higher, number of particulates: 1 pc/ml or less (0.05 $\mu$m or larger). bacteria count: 0.1 pc/l or less. TOC (Total Organic Carbon, index of organic snbstance) : 1ppb or less, dissolved oxygen: 5ppb or less, silica: 0.5ppb or less, heavy metal ions: 5ppb or less. The effect of metals on the silicon wafer has been well known, and recently it has been reported that the existence of organic substance in ultra-pure water is closely related to the device defect, drawing attention. It is reported that if organic substance sticks to the natural oxidation film, the oxide film remaims on the organic substance attachment in the hydrofluoric acid treatment (removal of natural oxidation film). The organic substance forms film on the silicon wafer, and harmful elements such as metals and N.P.S., components contained in the organic substance and the bad effect due to the generatinn of silicon carbide cannot be forgotten. In order to remove various impurities in raw water, many technological develoments (membrane, ion exchange, TOC removal, piping material, microanalysis, etc.) have been made with ultra-pure water producing equipment and put to practical use. In this paper, technologies put to practical use in recent ultra-pure vater producing equimeut are introduced.

• 폴리머
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• 제38권5호
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• pp.557-565
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• 2014

Sodium alginate and chitosan are added to a $CaCl_2$ solution to prepare calcium-alginate-chitosan and calciumalginate gels. After dehydration through stoving, two types of adsorbent particles are obtained. The adsorption process of the particles obtained for low concentrations of $Sr^{2+}$ satisfies a second-order kinetic equation and the Freundlich adsorption model. The thermodynamic behaviors of the particles indicate that adsorption occurs via a spontaneous physical process. XPS pattern analysis is used to demonstrate the adsorption of $Sr^{2+}$ by calcium alginate and chitosan. By building an interaction model of the molecules of chitosan and alginate with $Ca^{2+}$ and $Sr^{2+}$ to calculate energy parameters, Fukui index, Mulliken charge, and Mulliken population, adsorption of $Sr^{2+}$ on the molecular chains of chitosan as well as the boundary of calcium-alginate-chitosan is observed to show weak stability; by contrast, adsorption between molecular chains is high.

• 멤브레인
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• 제9권1호
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• pp.10-16
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• 1999

본 연구에서는 pellet 상태의 polyetherimide (PEI)를 carbon tetrachloride(CCl4)와 1 ,2-dichloro-ethane (DCE) 의 부피비 5:1 하에서 PEI를 불균일한 상태로 유지시키고, chlorosulfonic acid (CSA)를 이용하여 PEI의 표면을 sulfonation 시킴으로써 , 음이온성을 띠며 친수성이 향상된 sulfonated polyetherimide (SPEI)를 제조하였다. 불균일한 상태가 유지되면서 가장 적합한 sulfonation 반응조건은 PEI: CSA 의 1 : 1 mole ratio, 온도 $10^{\circ}$, 3 시간이었다. 이온교환용량이 0.2~1.2meq/g을 갖는 SPEI를 합성할 수 있었고, FT-IR 측정을 통하여 sulfonic acid peak가 1020$cm^{-1}$ 와 1170$cm^{-1}$부근에서 관찰되었다. 분자량 분포는 sulfonation을 시킴으로써 좀 더 넓게 나타났고, 접촉각 측정을 통하여 친수성이 향상되었음을 확인하였다.

• Journal of Electrochemical Science and Technology
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• 제8권1호
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• pp.35-42
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• 2017

In this study, the effect of electrolyte addition on the removal of organics and nutrients in electrochemical wastewater using a copper electrode, and the characteristics of the by-product of electrolysis were investigated. The removal of organics increased significantly as shorter reaction times upon the addition of chloride ion, and most of the electrolysis reaction was completed within 20 min. The reaction rate gradually increased in proportion to the $Cl^-$/COD ratio, whereas the highest removed mass of organic matter per mass of added electrolyte was observed at a $Cl^-$/COD ratio of 1. After the addition of electrolyte, significant removal of ammoniacal nitrogen was observed as a result of the enhanced generation of oxidizers such as hypochlorite. Excellent phosphorus removal was also achieved in a very short reaction time (within 2 min) by electro-coagulation. As the electrolysis progressed, the amount of by-product increased gradually, whereas a decrease of sludge volume index was observed after the addition of electrolyte. This indicated that the settling performance of the by-products was better, and their removal would be easily achieved.

• 한국광학회지
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• 제8권3호
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• pp.245-249
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• 1997

본 논문에서는 모드 결합을 최적화하기 위해 수정된 결합 영역을 갖는 전기광학 폴리머 디지탈 광스위치를 제작하였다. 분기형 도파로는 반응이온식각 방법을 이용하여 만들었다. 그리고, 수정된 결합 영역은 두 광도파로의 분기점에서부터 광파의 진행 방향을 따라 점진적으로 도입하였으며, 소자 제작 이후에 광표백 방법을 이용하여 구현하였다. 분기 영역에서 두 도파로 간의 모드 결합이 최적화 되도록 수정된 결합 영역의 구조와 굴절률 분포를 조절함으로써, 소자의 길이가 고정되어 있는 상태에서 스위칭 성능을 향상시켰다. 측정 결과에 의하면, 구동 전압은 약 30%이상 감소되었으며 누화는 4~6 dB정도 개선되었다.

• 한국자원식물학회지
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• 제28권4호
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• pp.533-540
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• 2015

Germination properties, leachate electrical conductivity (EC), and inorganic compound leaching were analyzed to ascertain the storage ability and change of physiological characteristics during storage of Hippophae rhamnoides seeds. Seeds were placed in an incubator at 25℃ and sown in different soil media (sand, vermiculite and horticultural substrate) after being stored for 6, 18 and 30 months at 2℃. All germination properties decreased in accordance to an increase of the seed storage period. Compared with the seed storage for 18 months, germination percentage (GP), germination performance index (GPI), and germination value (GV) of seeds stored for 30 months decreased by more than 50%. When the seeds were sown in different soil media in a greenhouse, those germination properties were similar to the seeds germinated in an incubator, and mean germination time, GPI and GV had a significant difference except GP among soil media. EC and inorganic ion concentration had a strong positive correlation with the seed storage period, but the ratios of inorganic ions from stored seeds revealed that K⁺/Mg²⁺ and Na⁺/Mg²⁺ were inversely correlated with the storage period.