• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.558-562
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• 2006

We have synthesized a new p-type polymer, poly(9,9'-n-dioctylfluorene-alt-phenoxazine) (PFPO), via the palladium catalyzed coupling reaction. The number average molecular weight ($M_n$) of PFPO was found to be 23,000. PFPO dissolves in common organic solvents such as chloroform and toluene. The UV-visible absorption maximum of the PFPO thin film is clearly blue-shifted with respect to that of F8T2, poly-(9,9'-n-dioctylfluorene-alt-bithiophene). The introduction of the phenoxazine moiety into the polymer system results in better field-effect transistor (FET) performance than that of F8T2. A solution processed PFPO TFT device with a top contact geometry was found to exhibit a hole mobility of $2.7{\times}10^{-4}cm^2/Vs$ and a low threshold voltage of -2 V with high on/off ratio(${\sim}10^4$).

• Asian-Australasian Journal of Animal Sciences
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• 제31권8호
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• pp.1308-1314
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• 2018

Objective: Gut health improvements were monitored with respect to growth performance, diarrhea incidence, fecal bacterial population and intestinal morphology of suckling pigs orally supplemented with live Lactobacillus salivarius (L. salivarius) oral suspensions and challenged with $F4^+$ enterotoxigenic Escherichia coli (ETEC). Methods: Two groups of newborn pigs from 18 multiparous sows were randomly designated as non-supplemented (control: n = 114 piglets) and L. salivarius supplemented groups (treatment: n = 87 piglets). Treatment pigs were orally administered with 2 mL of $10^9$ colony-forming unit (CFU)/mL L. salivarius on days 1 to 3, then they were orally administered with 5 mL of $10^9CFU/mL$ L. salivarius on days 4 to 10, while those in control group received an equal amount of phosphate buffered saline solution. On day 24 (2 weeks post supplementation), one pig per replicate of both groups was orally administered with $10^8CFU/mL$ $F4^+$ ETEC, then they were euthanized on day 29 of experiment. Results: Results revealed that pigs in treatment group had a statistically significant increase in average daily gain, body weight and weight gain, and tended to lower diarrhea throughout the study. Numbers of Lactobacillus population in feces of treatment pigs were higher than control pigs, especially on day 10 of study. Numbers of total bacteria in intestinal contents of control pigs were also increased, but not Coliform and Lactobacillus populations. Histological examination revealed statistically significant improvements of villous height and villous/crypt ratio of duodenum, proximal jejunum and distal jejunum parts of treatment pigs compared with controls. Duodenal pH of treatment group was significantly decreased. Conclusion: Oral supplementation of live L. salivarius during the first 10 days of suckling pig promoted growth performance and gut health, reduced diarrhea incidence, increased fecal Lactobacillus populations and improved intestinal morphology.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 춘계학술발표회 초록집
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• pp.71-72
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• 2007

In this study, we investigated the fabrication of MLR (multi-layer resist) with a very thin diamond-like carbon (DLC) layer. ArF PR/$SiO_2$/DLC MLR structure was investigated and etching characteristics of the DLC layer was patterned using $SiO_2$ hard-mask by varying the process parameters such as different high-frequency/low-frequency combination ($f_{LF}/f_{HF}$), HF/LF power ratio ($P_{HF}/P_{LF}$), $O_2$ flow and $N_2$ flow rate in $O_2/N_2$/Ar plasmas. The results indicated an increased etch rate of DLC for the higher $f_{LF}/f_{HF}$ combination and for the increased low-frequency power ($P_{LF}$). And the etch rate of DLC was decreased with increasing the $N_2$ flow rate in $O_2/N_2$/Ar plasmas. In order to confirm the application of DLC MLR for the etching process of silicon oxide, the stack of ArF PR/BARC/$SiO_2$/DLC/TEOS/Si was investigated.

• 한국해양공학회지
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• 제5권2호
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• pp.198-198
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• 1991

Not only difference of fatigue crack growth and propagation behavior resulted from the grain size, the hardness ratio and volume fraction in M.E.F. dual phase steel composed of martensite in hard phase and ferrite in soft phase, but also the effects of the plastic constraint were investigated by fracture mechanics and microstructural method. The main results obtained are as follows: 1) The fatigue endurance of M.E.F. steel increases with decreasing the grain size, increasing the ratio of hardness and volume fraction. 2) The initiation of slip and crack occures faster as the stress level goes higher. These phenomena result from the plastic constraint effect of the second phase. 3) The crack propagation rate in the constant stress level is faster as the grain size gets larger, the ratio of hardness lower and volume fraction smaller.

• 환경위생공학
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• 제22권4호
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• pp.119-130
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• 2007

Sea food wastewater including high concentration of organics and nutrients is hard to treat stably by established traditional activated sludge process. This research is aimed to obey more and more of strengthened the law and to secure stable effluents by using advanced treatment process applied membrane filter in aeration tank for treatment of wastewater from marine products. It must maintain pH of influent over 6.0 to keep up stably biological sludge of advanced treatment process. At 38hr of HRT, removal rates of TBOD and TCOD were 99.9% and 99.4% respectively and TSS also removed with high efficiency. Most organics in the effluent was constituted with soluble type materials, it caused that membrane filter installed aeration tank should remove minute suspended particles. The reactor was operated well to get stable treatment results for operation period, in spite of high loading of organics like that $0.67{\sim}1.67\;kgTBOD/m^3/day$ of organics loading and $0.10{\sim}0.21\;kgBOD_5/kgMLSS/day$ of F/M ratio. At $36{\sim}48hr$ of HRT, removal rates of T-N and T-P were $89.7{\sim}90.7%\;and\;91.5{\sim}96.0%$ respectively. It means this treatment process also work to remove nutrients of high concentration. Upon investigation of advanced treatment's operation factors, optimum SRT was about 30days and average SNR that showed tendency to increase according to increase water temperature was calculated 0.014 gN/g MLVSS/d. SDNR was risen in conformity to increase F/M ratio of Non-aeration tank and investigated as $0.038{\sim}0.051\;gN/gMLVSS/d$.

• Mass Spectrometry Letters
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• 제8권1호
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• pp.14-17
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• 2017

The effect of cationization agent concentration on glycan detection via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was investigated using $Na^+$ ions in the form of NaCl as the cationization agent. NaCl solution concentrations ranging from 1 mM to 1 M were investigated. Glycans from ovalbumin were mixed with the cationization agent solution and the 2,5-dihydroxybenzoic acid (2,5-DHB) matrix solution in a volume ratio of 1:1:1. The resulting mixture was loaded onto the MALDI plate. Two MALDI-TOF MS instruments (Voyager DE-STR MALDI-TOF MS and Tinkerbell RT MALDI-TOF MS) were used for detection of glycans. The best detection, in terms of the number of identified glycans, the peak intensity, and the signal-to-noise (S/N) ratio, was obtained with NaCl concentrations of 0.01-0.1 M for both MALDI-TOF MS instruments.

• Journal of Power Electronics
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• 제17권4호
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• pp.849-859
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• 2017

This paper illustrates the analysis and design of a multi-resonant converter applied to an electric vehicle (EV) charger. Thanks to the notch resonant characteristic, the multi-resonant converter achieve soft switching and operate with a narrowed switching frequency range even with a wide output voltage range. These advantages make it suitable for battery charging applications. With two more resonant elements, the design of the chosen converter is more complex than the conventional LLC resonant converter. However, there is not a distinct design outline for the multi-resonant converters in existing articles. According to the analysis in this paper, the normalized notch frequency $f_{r2n}$ and the second series resonant frequency $f_{r3n}$ are more sensitive to the notch capacitor ratio q than the notch inductor ratio k. Then resonant capacitors should be well-designed before the other resonant elements. The peak gain of the converter depends mainly on the magnetizing inductor ratio $L_n$ and the normalized load Q. And it requires a smaller $L_n$ and Q to provide a sufficient voltage gain $M_{max}$ at ($V_{o\_max}$, $P_{o\_max}$). However, the primary current increases with $(L_nQ)^{-1}$, and results in a low efficiency. Then a detailed design procedure for the multi-resonant converter has been provided. A 3.3kW prototype with an output voltage range of 50V to 500V dc and a peak efficiency of 97.3 % is built to verify the design and effectiveness of the converter.

• 한국자기학회지
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• 제14권6호
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• pp.236-239
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• 2004

미소 자유자성층에 인접한 스핀필터층 (SFL; spin filter layer)을 갖는 Ta3/NiFe2/IrMn7/CoFe1/(NOL1)/CoFe2/Cu 1.8/CoFe( $T_{f}$)/Cu( $t_{SF}$ )/(NOL2)/Ta3.5 (두께단위 nm) 구조의 스페큘라 스핀밸브 (SSV; specular spin valve)를 마그네트론 스퍼터링 장치를 사용하여 제작하였다. 반강자성체 I $r_{22}$M $n_{78}$을 속박층으로 한 스핀필터 스페큘라 스핀밸브 (SFSSV; spin filter specular spin valve) 박막에 대하여 자유자성층의 두께 ( $t_{F}$)와 SFL의 두께 ( $t_{SF}$ )가 각각 1.5nm일 때 극대 자기저항 (MR; magnetoresistance)비 11.9%를 얻었으며, $t_{SF}$ 가 1.0nm으로 감소하여도 11%이상의 MR비를 유지하였다. 이것은 나노산화층 (NOL; nano-oxide layer)에 의한 스페큘라 전자와 SFL에 의한 전류분류효과의 증가 때문이다. 또한, 자유자성층과 피속박층 사이의 층간결합장 ( $H_{int}$; interlayer coupling field)은 RKKY력과 정자기결합력으로 설명할 수 있다. 자유자성층의 보자력 ( $H_{cf}$ ; coercivity of the free layer)은 기존의 스핀밸브 (TSV; traditional spin valve)에 비해 현저히 감소했으며, $t_{F}$가 1nm에서 4nm로 변하여도 4 Oe이하의 값을 유지하였다. 따라서 SFL의 삽입으로 자유자성층의 연자성 특성을 떨어뜨리지 않으면서 자유자성층 두께의 감소와 MR비의 향상을 가능하게 하였다.

• Transactions on Electrical and Electronic Materials
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• 제15권2호
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• pp.81-86
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• 2014

The process parameter in optimized KOH alkali activation of soft carbon series coke material in high purity was set with DOE experiments design. The activated carbon was produced by performing the activation process based on the set process parameters. The specific surface area was measured and pore size was analyzed by $N_2$ absorption method for the produced activated carbon. The surface functional group was analyzed by Boehm method and metal impurities were analyzed by XRF method. The specific surface area was increased over 2,000 $m^2/g$ as the mixing ratio of activation agent increased. The micro pores in $5{\sim}15{\AA}$ and surface functional group under 0.4 meq/g were obtained. The contents of the metal impurity in activated carbon which is the factor for reducing the electrochemical characteristics was reduced less than 100 ppm through the cleansing process optimization. The electrochemical characteristics of activated carbon in 38.5 F/g and 26.6 F/cc were checked through the impedance measuring with cyclic voltammetry scan rate in 50~300 mV/s and frequency in 10 mHz ~100 kHz. The activated carbon was made in the optimized activation process conditions of activation time in 40 minutes, mixing ratio of activation agent in 4.5 : 1.0 and heat treatment temperature over $650^{\circ}C$.

• BMB Reports
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• 제35권3호
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• pp.313-319
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• 2002

N-Acetyl-$\beta$-D-hexosaminidase ($\beta$-HexNAc'ase) (EC 3.2.1.52) was purified from rice seeds (Oryza sative L. var. Dongjin) using ammonium sulfate (80%) precipitation, Sephadex G-150, CM-Sephadex, and DEAE-Sephadex chromatography, sequentially. The activities were separated into 7 fractions($F_1-F_7$) by CM-Sephadex chromatography. Among them, F6 was further purified to homogeneity with a 13.0% yield and 123.3 purification-fold. The molecular mass was estimated to be about 52 kDa on SDS-PAGE and 37.4 kDa on Sephacryl S-300 gel filtration. The enzyme catalyzed the hydrolysis of both p-nitrophenyl-N-acetyl-$\beta$-D-hexosaminide (pNP-GlcNAc) and p-nitrophenyl-N-acetyl-$\beta$-D-hexosaminide (pNP-GalNAc) as substrates, which are typical properties of $\beta$-HexNAc'ase. The ratio of the pNP-GlcNAc'ase activity to the pNP-GalNAc'ase activity was 4.0. However, it could not hydrolyze chitin, chitosan, pNP-$\beta$-glucopyranoside, or pNP-$\beta$-glucopyranoside. The enzyme showed $K_m$, $V_{max}$ and $K_{cat}$ for pNP-GlcNAc of 1.65 mM, $79.49\;mM\;min^{-1}$, and $4.79{\times}10^6\;min^{-1}$, respectively. The comparison of kinetic values for pNP-GlcNAc and pNP-GalNAc revealed that the two enzyme activities are associated with a single binding site. The purified enzyme exhibited optimum pH and temperature for pNP-GlcNAc of 5.0 and $50^{\circ}C$, respectively. The enzyme activity for pNP-GlcNAc was stable at pH 5.0-5.5 and $20-40^{\circ}C$. The enzyme activity was completely inhibited at a concentration of 0.1 mM $HgCl_$ and $AgNO_3$, suggesting that the intact thiol group is essential for activity. Chloramine T completely inhibited the activity, indicating the possible involvement of methionines in the mechanism of the enzyme.