• Macromolecular Research
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• 제16권7호
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• pp.590-595
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• 2008

The pressure driven membrane process has been a breakthrough in the removal of pollutants from drinking water. These experiments examined the removal of chlorophenol compounds from water using low pressure membranes. The removal performance of the membranes was based primarily on size exclusion. Apart from size exclusion, the polarity and pKa of the compounds also influences the membrane performance. The molecular size and dipole moments of the respective molecules were calculated using a quantum chemical method. The rejection of pollutants also followed the same trend as salt rejection by the membranes.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.36-37
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• 2003

To increase the high-density data storage, a new technique of Super-resolution near-field structure (Super-RENS) consisted of glass／SiN／Sb or AgOx／SiN has been proposed and investigated intensively as a promising structure for near-field ultrahigh-density optical storage. Hence it is important to determine the optical properties of AgOx by using ellipsometry. AgOx thin films were prepared by using magnetron sputtering technique while oxygen flow rate was varied, and the film growth of AgOx were monitored by using in situ ellipsometer. (omitted)

• Journal of Korean Vacuum Science & Technology
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• 제6권1호
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• pp.30-35
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• 2002

We show that a combined technique of Cs$^{+}$ reactive ion scattering (Cs$^{+}$ RIS) and low-energy secondary ion mass spectrometry (LESIMS) provides a powerful means for probing molecular films and their surface reactions. Simple molecules, including HCI, NH$_3$, D$_2$O, and their mixtures, were deposited into a thin film of several monolayer thickness on Ru(001) at low temperature in vacuum, and the surface was characterized by Cs$^{+}$ RIS and LESIMS. On pure films, D$_2$O, HCI, and NH$_3$ existed in the corresponding molecular states. When HCI and NH$_3$ were co-deposited, ammonium ion(NH$_4$$^{+}$) was readily formed by proton transfer from HCI to NH$_3$. In the presence of water molecules, HCI ionized first to hydronium ion(H$_3$O$^{+}$), which subsequently transferred proton to NH$_3$ to form NH$_4$$^{+}$. The proton transfer, however, did not occur to a completion on ice, in contrast to the complete reaction in aqueous solutions.s solutions.

• 분석과학
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• 제15권3호
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• pp.229-235
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• 2002

폴리스티렌 시료의 표면을 플라즈마 이온주입(PSII) 기술로 처리하여 친수성을 향상시켰다. 친수성이 향상된 표면은 시간이 지남에 따라 원래 성질인 소수성으로 되돌아가려는 특성 (aging effect)이 있는데 본 연구에서는 각각 분자량이 다른 폴리스티렌 필름을 이용하여 분자량에 따른 에이징 효과를 살펴보았다. 무게평균 분자량이 각각 $M_w$ = 760, 2430, 31600, 115700, 280000, 903600 인 폴리스티렌을 가스종류와 펄스전압 등의 PSII 실험 변수에 따라 표면 친수성 변화를 측정하였고 PSII 처리 후 보관온도를 달리하여 분자량에 따른 에이징 정도를 관찰하였다. 분자량이 큰 폴리스티렌이 시간에 따른 에이징 현상이 적게 일어났으며 펄스전압과 보관온도가 높은 조건에서도 사슬이 긴 폴리스티렌이 에이징이 덜 되었다. 물 접촉각을 측정하여 표면 친수성을 나타내었으며 처리 후 표면 구조 변화를 관찰하기 위하여 SEM과 AFM을 이용하였고, TOF-SIMS와 XPS를 통하여 표면에 생성된 작용기들을 확인하였다.

• Korean Chemical Engineering Research
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• 제49권5호
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• pp.669-675
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• 2011

다공성 구조로 되어있는 차세대 저유전 박막(k<2.0)의 나노 기공의 초기 형성 과정을 이해하기 위하여 실세스퀴옥산(silsesquioxane; SSQ) 매트릭스에서 분산된 4-tert-butyl calix[4]arene-O,O',O",O"'-tetraacetic acid tetraethyl ester(CA[4]) 포로젠이 열분해에 의해서 나노 기공으로 전환되는 과정을 Fourier Transform Infrared Spectroscopy(FT-IR)와 in-situ Position Annihilation Lifetime Spectroscopy(PALS) 연구를 통해 분석하였다. SSQ/CA[4] 하이브리드 시스템은 열 경화에 따라 효과적인 기공 구조의 균일한 박막을 제공하였다. SSQ/CA[4] 10, 20% 두 종류의 하이브리드 박막을 in-situ PALS 분석을 시행한 결과, CA[4] 포로젠의 분해 거동이 달랐다. SSQ/CA[4] 10% 하이브리드 박막은 $300^{\circ}C$ 이상부터 단분자 포로젠으로부터 기인한 메조포어(~1.5 nm)가 생성되기 시작하였으나, SSQ/CA[4] 20% 하이브리드 박막은 상대적으로 낮은 온도인 $250^{\circ}C$부터 상태로 CA[4] 분자들이 자가 조립된 마이셀로부터 기인한 메조포어(2.5~3.0 nm)가 생성되었다. 이는 SSQ/CA[4] 20% 하이브리드 박막에서 생성된 기공의 구조가 매우 연결된 상태이기 때문에 초기에 포로젠이 분해되었을 때, 분해된 분자조각들이 쉽게 박막 외부로 빠져나올 수 있기 때문이라고 생각된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1247-1250
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• 2008

This presentation highlights work from the authors' laboratories on the various kinds of oxide optical materials, mainly luminescence and pigment materials with different forms (powder, core-shell structures, thin film and patterning) prepared by the Pechini-type sol-gel (PSG) process. The PSG process which uses the common metal salts (nitrates, acetates, chlorides etc) as precursors and citric acid (CA) as chelating ligands of metal ions and polyhydroxy alcohol (such as ethylene glycol or poly ethylene glycol) as cross-linking agent to form a polymeric resin on molecular level, allowing the preparation of many forms of luminescent materials.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.299-304
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• 2003

We discuss several key technologies of liquid crystal displays (LCDs) that share common features of all organic displays (AODs). An overview of the morphological effects associated with molecular ordering at interfaces on the Crystallinity and the carrier mobility in organic thin film transistors (OTFTs) is given from the viewpoint of the alignment mechanism for LCDs. Recent progress of improving the carrier mobility in the OTFTs is also reviewed.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 춘계 총회 및 학술발표회
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• pp.82-85
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• 2004

Flux-enhancement mechanism of thin-film-composite (TFC) membranes for the reverse comosis (RO) process was newly explained by positron annihilation lifetime spectroscopy (PALS) that has been found to be applied for detecting molecular vacancies or pores having sizes that are equivalent to salt or hydrate ions in RO membrane.(omitted)

• 전기학회논문지P
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• 제57권2호
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• pp.140-145
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• 2008

The purpose of this paper is to discuss the fabrication of $\beta$-PVDF($\beta$-Polyvinylidene fluoride, ${\beta}-PVF_2$) organic thin films using the vapor deposition method. Vapor deposition was performed under the following conditions: the temperature of evaporator, the applied electric field, and the pressure of reaction chamber were $270^{\circ}C$, 142.4 kV/cm, and $2.0{\times}10^{-5}\;Torr$, respectively. The molecular structure of the evaporated organic thin films were evaluated by a FT-IR. The results showed that the characteristic absorption peaks of $\beta$-form crystal increase from 72% to 95.5% with an increase in the substrate temperature. In the analysis of the electric characteristics, the abnormal increases in the relative dielectric constant and the dielectric loss factor in the regions of low frequency and high temperature are known to be caused by inclusion of impurity carriers in the PVDF organic thin films. In order to analyze quantitatively the abnormalities in the conductivity mechanism caused by ionic impurities, the product of the ion density and the mobility that affect the electrical property in polymeric insulators is analyzed. In the case of a specimen produced by varying the substrate temperature from $30^{\circ}C$ to $105^{\circ}C$, the product of mobility and the ion density decreased from $4.626{\times}10^8$ to $8.47{\times}10^7/V{\cdot}cm{\cdot}s$. This result suggests that the higher the substrate temperature is maintained, the better excluded the impurities are, and the more electrically stable material can be obtained.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.161-164
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• 2001

Transmuted impurity atoms formed in neutron-irradiated ZnO thin films were theoretically identified first and then experimentally confirmed by Photoluminescence (PL). ZnO thin films grown by plasma-assisted molecular beam epitaxy were irradiated by neutron beam at room temperature. Among eight isotropes naturely exiting in ZnO films, only $^{64}Zn$, $^{68}Zn$, $^{70}Zn$ and $^{18}O$ were expected to transmute into $^{65}Cu$, $^{69}Ga$, $^{71}Ga$ and $^{19}F$, respectively. The concentrations of these transmuted atoms were estimated by considering natural abundance, neutron fluence, and neutron cross section. The neutron-irradiated ZnO thin films were characterized by PL. In the PL spectra of these ZnO thin film, the Cu-related PL peaks were seen, but the Ga- or F-associated PL peaks were absent. This observation demonstrates the existence of $^{65}Cu$ in the ZnO. In this paper, emission mechanism of Cu impurities wil1 be described and the reason for the absence of the Ga- or F-associated PL peaks will be discussed.