• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.129-133
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• 2000

Boron nitride films were synthesized with $N_2$ion flux of low energy, up to 100 eV, at different substrate temperatures of no heating, 200, 400, 500, and $800^{\circ}C$, respectively. Boron was supplied by e-beam evaporation at the rate of $1.5\AA$/sec. For all the conditions, hexagonal BN (h-BN) phase was mainly synthesized and high resolution transmission electron microscopy (HRTEM) showed that (002) planes of h-BN phase were aligned vertical to the Si substrate. The maximum alignment occurred around $400^{\circ}C$. In addition to major h-BN phase, transmission electron diffraction (TED) rings identified the formation of cubic BN (c-BN) phase. But HRTEM showed no distinct and continuous c-BN layer. These results suggest that c-BN phase may form in a scattered form even when h-BN phase is mainly synthesized under small momentum transfer by bombarding ions, which are not reconciled with the macro compressive stress model for the c-BN formation.

• Progress in Superconductivity
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• v.9 no.2
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• pp.162-166
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• 2008

We are developing a sensitive gamma ray spectrometer based on superconducting transition edge sensors. The detector consists of a small piece of high purity Sn as an absorber and a Ti/Au bilayer as a temperature sensor. It is designed to measure the thermal signal caused by absorption of gamma rays. The mechanical support and the thermal contact between the absorber and the thermometer were made with Stycast epoxy. The bilayer was formed by e-beam evaporation and patterned by wet etching on top of a $SiN_X$ membrane. A sharp superconducting transition of the film was measured near 100 mK. When the film was biased to the edge of the transition, signals were observed due to single photon absorption emitted from an $^{241}Am$ source. The measured spectrum showed several characteristic peaks of the source including 59.5 keV gamma line. The full with at half maximum was about 900 eV for the 59.5 keV gamma line. The background was low enough to resolve low energy lines. Considerations to improve the energy resolution of the gamma ray spectrometer are also discussed.

• 한국전기화학회:학술대회논문집
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• 2004.11a
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• pp.75-108
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• 2004

The market, development and trend of Lithium ion Batteries in China are introduce briefly. Early, Chinese manufactories were busy to expand and many new battery factories have been built up. Now, the relatively large companies pay more attentions on comprehensive quality improvement, therefore the production processing and facilities have been also modified in some extent. The recent technology progresses focus on High capacity (energy density), High rate, High average voltage, High safety, High temperature properties, Long cycle life, Low temperature properties, Low self discharge, Low cost, Super-large, Super-small, Super-thin, Consistency, Customization, and Environment friendly processing, simply $H_5L_4S_3C_2E_1$. Lithium ion polymer batteries which all batteries packaged with soft lamination film are named as in China have a quick growth and emphasized here because of their advantages ins $H_5L_4S_3C_2E_1$ for which it is quite difficult to be realized at the same time. Some of research works such as listed above are introduced. The other contends related to application trend of Lithium ion batteries and projects carrying out are also included.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.101-109
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• 2002

The electrical properties of polyethylene are changed by the superstructure. Such crystalline polymer as polyethylene or polypropylene changes crystallinity and products spherulite or trans-crystal when it is cooled slowly. In this study, after thermal treatment of LDPE at 100[${circ}C$], in silicone oil for an hour, we made specimens in order of slow cooling, water cooling, quenching according to cooling speed. Also, to study the influence of electrical properties due to the superstructure change, we analyzed physical properties and performed dielectric breakdown experiments using DC and impulse voltage Moreover we measured space charges in bulk using Laser Induced Pressure Pulse(LIPP) method. Trap level of specimen is 0.064[eV] at the low temperature region 0.31[eV] at the high temperature region in DC dielectric strength, 0.03[eV] at the low temperature region 0.0925[eV] at the high temperature region in impulse dielectric strength. As its result shows that the quantity of charges induced from the electrode surface increases with applied voltage time, and the distribution of space charges in samples increases the quantity of charges in proportion to applied voltage.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.524-524
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• 2006

For decades, the pursuit of volume commercialization of low-power reflective displays with a paper-like look has been an unfulfilled dream. While steady technical progress was made throughout the late 1990s, there were still no volume products incorporating electronic paper displays (EPD) on the market. Now, microencapsulated electrophoretic display technology, also called electronic ink, has moved into volume production with a frontplane laminate (FPL) display component called E Ink Imaging Film™. This film is coated roll to roll on a flexible plastic substrate and integrated into a display module. Today, all-plastic segmented displays are being shipped as well as displays with electronic ink FPL being driven by glass TFT backplanes. A roadmap to active matrix flexible electrophoretic displays is being enabled by rapid technical progress on flexible TFT backplanes by a variety companies. Each of the approaches to these backplanes and flexible active matrix displays has different advantages for the various market segments being pursued including large format flexible displays for e-news and other reader applications, rollable displays for compact readers, and high resolution small format displays up to 400 ppi that can have fully integrated drive electronics to reduce size and drive down costs. Backplane approaches include Si on plastic, organic transistors on plastic, and Si transistors on flexible stainless steel substrate. Progress is also being made on next generation inks, including more reflective inks with higher contrast ratios. A full color 6 inch, 170 pixel per inch (PPI) active matrix display using a newer generation ink has been developed and this will be described and demonstrated. Large format segmented flexible displays will also be described.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.262-263
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• 2001

저방출 코팅(low-e coating)이란 열 방출에 해당하는 적외선 파장이 가능한 작게 투과하도록 기판 위에 박막을 증착하는 방법이다. 그러므로 유리 기판 위에 저방출 코팅을 하는 것은 냉방시설을 갖춘 건축물 내부에서 에너지 절약과 쾌적한 환경을 구현하거나 자동차 내부의 빠른 온도상승을 저하시키는데 이용될 수 있다. 본 연구에서는 원격 조정 장치의 적외선 파장이 디스플레이의 광원에서 나올 수 있는 동일 파장에 의해 간섭을 받지 않도록 적외선 영역의 투과율은 낮추고 가시광선 영역의 투과율은 높이는 설계를 하고 최적화 하였다. (중략)

• Journal of the Korean Chemical Society
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• v.14 no.1
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• pp.29-35
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• 1970

Chacterization of MMA/AN organosol copolymer and subsequent comparison with the prior art latex copolymers has been accomplished. By means of NMR analyses, we found both types of copolymers to be random. The GPC analyses show that the organosol copolymers have a singnificantly broader MW spread than latex copolymers. This is due to the low MW stabilizer which is present as a physical mixture. As a result, the MW distribution is bimodal. Fractionation of a typical organosol copolymer yields a low MW(33,000-100,000), MMA rich fraction and a high MW (250,000-330,000), AN rich fraction. Solubility-wise, the organosol copolymers are readily soluble in the lacquer solvent MEK to give a colorless film. The prio rart copolymers, hewever, were imcompletely soluble and gave yellow, hazy film.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.245-250
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• 2006

The effects of aliphatic hydrocarbons (n-hexadecane and n-dodecane) on the volumetric oxygen mass transfer coefficient $(k_L\;a)$ were studied in flat alveolar airlift reactor and continuous stirred tank reactors (CSTRs). In the flat alveolar airlift reactor, high aeration rates (>2vvm) were required in order to obtain efficient organic-aqueous phase dispersion and reliable $k_La$ measurements. Addition of 1% (v/v) n-hexadecane or n-dodecane increased the $k_La$ 1.55- and 1.33-fold, respectively, compared to the control (superficial velocity: $25.8{\times}10^{-3}m/s$, sparger orifice diameter: 0.5 mm). Analysis of the gas-liquid interfacial area a and the liquid film mass transfer coefficient $k_L$ suggests that the observed $k_La$ increase was a function of the media's liquid film mass transfer. Addition of 1% (v/v) n-hexadecane or n-dodecane to analogous setups using CSTRs led to a $k_La$ increase by a factor of 1.68 and 1.36, respectively (superficial velocity: $2.1{\times}10^{-3}m/s$, stirring rate: 250 rpm). These results propose that low-concentration addition of oxygen-vectors to aerobic microbial cultures has additional benefit relative to incubation in purely aqueous media.

• Journal of the Korean institute of surface engineering
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• v.46 no.1
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• pp.16-21
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• 2013

CIGS (Cu-In-Ga-Se) films were deposited on the Mo coated soda lime glass (Mo/SLG) by RF magnetron sputtering using a single sintered target with different chemical compositions. Heat treatment of the CIGS films were carried out under three different conditions, 1step ($350^{\circ}C$ for 2 hour and $550^{\circ}C$ for 2 hour) and 2step ($350^{\circ}C$ for 1 hour and $550^{\circ}C$ for 1 hour). In the case of CIGS films post-annealed on 2step method, grain size remarkably increased compared to other methods, indicating that chemical composition [Cu/(Ga+In) = 1] of CIGS films was same as CIGS target. After heat treatment by 2step method, band gap energy of the CIGS film deposited at RF 80 W showed 1.4 eV which is broadly similar to identical band gap energy (1.2 eV) of CIGS film prepared by evaporation method. Therefore, 2step heat treatment method could be expected to low temperature process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.47-47
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• 2008

P-type transparent semiconductor $SrCu_2O_2$ thin films have been prepared by RF sputtering using low-alkali glass for LCD and quartz as substrates. Single phase of $SrCu_2O_2$ powder was obtained by heating a stoichiometric mixture of CuO and $SrCO_3$ at 1223K for 96h under N2 gas flow, and target was fabricated at 1243K for 24h. Room temperature conductivity of the sintered body was about 0.02S/cm, and the activation energy in the temperature range of $-50^{\circ}C$~RT and RT~$150^{\circ}C$ were 0.18eV, 0.07eV, respectively. Effects of deposition pressure and post-annealing temperature on the electrical and optical properties of the obtained thin film have been investigated.