• Title/Summary/Keyword: Heated substrate

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A Preponderant Enhancement of Conversion Efficiency by Surface Coating of $SnO_2$ Nanoparticles in Organic MK-2 Dye Sensitized Solar Cell

  • Son, Dae-Yong;Lee, Chang-Ryul;Park, Nam-Gyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.218-218
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    • 2012
  • Nanocrystalline $SnO_2$ colloids are synthesized by hydrolysis of $SnCl_4{\cdot}5H_2O$ in aqueous ammonia solution. The synthesized $SnO_2$ nanoparticles with ca. 15 nm in diameter are coated on a fluorinedoped thin oxide (FTO) conductive substrate and heated at $550^{\circ}C$. The annealed $SnO_2$ film is treated with aqueous $TiCl_4$ solution, which is sensitzied with MK-2 dye (2-cyano-3-[5'''-(9-ethyl- 9H-carbazol-3-yl)-3',3'',3''',4-tetra-n-hexyl-[2,2',5',2'',5'',2''']-quater thiophen-5-yl]). Compared to bare $SnO_2$ film, the conversion efficiency is significantly improved from 0.22% to 3.13% after surface treatment of $SnO_2$ with $TiCl_4$, which is mainly due to the large increases in both photocurrent density from 1.33 to $9.46mA/cm^2$ and voltage from 315 to 634 mV. It is noted that little change in the amount of the adsorbed dye is detected from 1.21 for the bare $SnO_2$ to $1.28{\mu}mol/cm^2$ for the $TiCl_{4-}$ treated $SnO_2$. This indicates that the photocurrent density increased by more than 6 times is not closely related to the dye loading concentration. From the photocurrent and voltage transient spectroscopic studies, electron life time increases by about 13 order of magnitude, whereas electron diffusion coefficient decreases by about 3.6 times after $TiCl_4$ treatment. Slow electron diffusion rate offers sufficient time for regeneration kinetics. As a result, charge collection efficiency of about 40% before $TiCl_4$ treatment is improved to 95% after $TiCl_4$ treatment. The large increase in voltage is due to the significant increase in electron life time, associated with upward shift of fermi energy.

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Preparation of $Gal^3Man_4(6^3-mono-{\alpha}-D-galacto-pyranosyl-{\beta}-mannotetraose)$ by Bacillus sp. ${\beta}-mannanase$ and Growth Activity to Intestinal Bacteria (Bacillus sp.유래 ${\beta}-mannanase$에 의한 $Gal^3Man_4(6^3-mono-{\alpha}-D-galacto-pyranosyl-{\beta}-mannotetraose)$ 조제 및 장내세균에 대한 생육활성)

  • Kim, Sang-Woo;Park, Gwi-Gun
    • Applied Biological Chemistry
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    • v.47 no.4
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    • pp.379-383
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    • 2004
  • For the elucidation of substrate specificity to the brown copra meal by Bacillus sp. ${\beta}-mannanase.$, the enzymatic hydrolysate after 24 hr of reaction was heated in a boiling water bath for 10 min, and then centrifuged to remove the insoluble materials from hydrolysates. The major hydrolysates composed of D.P 5 and 7 galactosyl mannooligosaccharides. For the separate of galactosyl mannooligosaccharides, the supernatant solution of 150 ml was put on a first activated carbon column. The column was then washed with 5 l of water to remove mannose and salts. The oligosaccharides in the column were eluted by a liner gradient of $0{\sim}30%$ ethanol, at the flow rate of 250 ml per hour. The sugar composition in each fraction tubes was examined by TLC and FACE analysis. The combined fraction from F3 was concentrated to 30 ml by vacuum evaporator. Then put on a second activated carbon column. The oligosaccharides in the column were eluted by a liner gradient of $0{\sim}30%$ ethanol (total volume: 5 l), at the flow rate of 250 ml per hour. The eluent was collected in 8 ml fraction tubes, and the total sugar concentration was measured by method of phenol-sulfuric acid. The major component of F2 separated by 2nd activated carbon column chromatography were identified $Gal^3Man_4(6^3-mono-{\alpha}-D-galactopyranosyl-{\beta}-mannotetraose)$. To investigate the effects of brown copra meal galactomannooligosaccharides on growth of Bifidobacterium longum, B. bifidum were cultivated individually on the modified-MRS medium containing carbon source such as $Gal^3Man_4$, compared to those of standard MRS medium.

Antioxidant Activity of Various Solvent Extracts Obtained from A Maillard-type Browning Reaction Mixture (각종용매(各種溶媒)로부터 추출(抽出)한 Maillard형(型) 갈색화반응(褐色化反應) 생성물(生成物)의 산화억제작용(酸化抑制作用))

  • Won, Jong-Tai;Kim, Dong-Hoon
    • Korean Journal of Food Science and Technology
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    • v.12 no.4
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    • pp.235-241
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    • 1980
  • Equal portions of a Maillard-type browning mixture (0.2 M glucose+0.2 M glycine), heated at $100^{\circ}C$ for 12 hr, were extracted with the same amounts of eight solvents, respectively. The extracts were then dissolved in equal amounts of an edible soybean oil, and the resulting substrates and a portion of the soybean oil (Control) were stored in an incubator kept at $45.0{\pm}1.0^{\circ}C$ for three weeks. Peroxide values and TBA values of Control and the substrates were determined regularly during the storage period. The POVs of Control and the substrates containing acetone, benzene, chloroform, ethanol, diethyl ether, methanol, methylene chloride, and petroleum ether extracts after 12 days of storage were respectively $60.0{\pm}3.6$, $31.9{\pm}0.9$, $37.6{\pm}2.2$, $48.1{\pm}1.1$, $11.9{\pm}1.3$, $4.85{\pm}0.4$, $11.5{\pm}1.0$, $45.3{\pm}0.3$, and $43.3{\pm}4.2\;m.\;mole/kg\;oil$. The TBA values after 16 days of storage were respectively $0.28{\pm}0.02$, $0.20{\pm}0.01$, $0.21{\pm}0.01$, $0.26{\pm}0.03$, $0.16{\pm}0.02$, $0.28{\pm}0.02$, $0.17{\pm}0.01$, $0.33{\pm}0.05$, and $0.31{\pm}0.02$. The induction periods (arbitrarily taken as the time in hours for a substrate to reach a peroxide value of 30 m. mole/kg oil) of Control and the substrates were respectively 193, 280, 252, 220, 478, 229, 455, 217, and 214 hr. The antioxidant activity of each extract estimated on the basis of the length of the induction periods was, in decreasing order, as follows; ethanol>methanol>acetone>benzene>diethyl ether>chloroform, pertroleum ether, methylene chloride.

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PHENOLOXIDASE AND ANTIOXIDANT IN KOREAN GINSENG (고려인삼에 있어서의 페놀 산화효소의 항산화물질)

  • Park E.Y.;Luh B.S.;Branen A.L.
    • Proceedings of the Ginseng society Conference
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    • 1984.09a
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    • pp.257-275
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    • 1984
  • Enzymatic browning is considered desirable in tea and tobacco processing but undesirable in many fruits processing at the present time. It is necessary to understand the nature of the enzyme, phenoloxidase, in order to control browning reactions, and extend its effects to formation of browning products as antioxidants in ginseng. Ginseng exhibits antioxidant activity when incorporated with turkey dark meat patties. The activity in red ginseng showed about two times stronger than white ginseng. One of the phenolic antioxidants from fresh, white and reprocessed white ginseng was identified as phenol 2.6 Bis(1.1 dimethyl ethyl) 4-methyl among several unknown compounds by GC/mass spectrometer. In red ginseng, no phenol 2.6 Bis (1.1 dimethyl ethyl) 4-methyl was detected, the compound may be polymerized by phenoloxidase and form some higher molecular compounds which may possess high antioxidant activity. Phenoloxidase isozymes in fresh Korean ginseng (panax ginseng C.A. Meyer) were extracted with phosphate buffer at pH 7.3. The isozymes were purified through ammonium sulfate fractionation, dialysis and chromatography on a DEAE-cellulose column. Two groups of phenoloxidase were shown to be present, one in the floating agglomerated group and the other in the precipitate. group from the 0.85 saturation ammonium sulfate. The DEAE-cellulose column chromatography, the phenoloxidase isozyme present in the precipitate appears as the first peak (I), and that in the agglomerate in the second peak (II). Isozyme I showed higher activity with catechin and catechal, and isozyme II showed higher activity with p-cresol. The isozyme showed two optimum pH activity one at pH 4.5 and the other at 8.5 with catechin as substrate. Korean ginseng phenoloxidase has high heat stability. When heated at $75^{\circ}C$ for 2 hours, its activity remained $90\%\;and\;80\%$ on phenoloxidase I and II respectively. Phenoloxidase I was most active on (+) catechin followed by p-cresal, catechol and epicatechin. Phenoloxidase II was most active on p-cresal followed by (+) catechin, catechol, p-coumanic acid and epicatechin. Sodium bisulfite, sodium cyanide, ascorbic acid glutachion in the oxidized form, sodium diethyl dithiocarbomate and ethylendiamine tetra acetate (EDTA) acted as inhibitors. Red ginseng color development was initiated by phenoloxidase and finished by a followed sun drying process. The antiaging activity of ginseng may be initiated by the antioxidant in the ginseng.

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A study of apatite formation on NaOH treated Ti alloys with different Iron content (NaOH 처리한 Fe 첨가된 Ti alloys의 아파타이트 형성관찰)

  • Seung-Woo Lee;Yun-Jong Kim;Jae-Gyeoung Ruy;Taik-Nam Kim
    • The Journal of Engineering Research
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    • v.6 no.2
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    • pp.23-32
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    • 2004
  • Metals, ceramics and polymers are widely used as bioimplant materials. However, Ti and Ti alloys are widely used because of its high strength to weight ratio and good biocompatibility when implanted in the body. In this experiment, Ti alloys of Grade-4 (gr4), 0.2 wt % Fe, 0.5 wt % Fe and 2 wt % Fe were studied for their surface morphology and HAp forming ability on the metal substrate for different treatments. Intially, the samples were mechanically polished on silicone carbide paper (No.-2000). The polished samples were treated with 5M NaOH solution at $60^{\circ}C$ for 24 hours. The NaOH treated samples were washed gently with distill water and dried at $40^{\circ}C$ for 1 day. The dried samples were heated in air at $600^{\circ}C$ for 1 hour. The surface morphology of these samples were studied using SEM. The SEM studies showed network of pores in all samples. These samples were immersed in stimulated body fluids (SBF) kept at $36.5^{\circ}C$ for different periods over the length of 1 to 14 days. The apatite formation was confirmed on all Ti-alloys using EDAX.

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Antioxidative Effect of Methionine and Lysine on Oil Rancidity (유지의 산화에 대한 Methionine과 Lysine의 항산화 효과)

  • 박성원;안명수
    • Korean journal of food and cookery science
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    • v.10 no.1
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    • pp.57-62
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    • 1994
  • Soybean oil and lard containing different level (0.02, 0.1, 1%) of methionine, lysine and some antioxi-dants (TBHQ, a-tocopherol) were stored at 60$^{\circ}C$ and heated at 180$^{\circ}C$ to compare their antioxidative effects. Peroxide values (POV) and acid values (AV) of each oil were monitored. Methionine and Iysine showed antioxidative effects in all concentration and the higher concentration, the higher effect. In case of incubating antioxidative effect of methionine was similer to that of TBHQ and that of lysine was considerably higher than that of a-tocopherol, but was lower than that of methionine. In case of heating the antioxidative effects of methionine and lysine were showed higher than those of THHQ and u-tocopherol. Methionine and lysine also had higher antioxidative effects in animal fat than in vegetable oil. Synergistic effects among methionine, Lysine and some food antioxidants were shown to be available in all substrates and the best effect was shown in substrate added com-pound of methionine and a-tocopherol.

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A Study on the Effect of O$_2$ annealing on Structural, Optical, and Electrical Characteristics of Undoped ZnO Thin Films Deposited by Magnetron Sputtering (산소 어닐링이 마그네 트론 스퍼터링으로 증착된 undoped ZnO박막의 구조적, 광학적, 전기적 특성에 미치는 영향에 대한 연구)

  • Yun, Eui-Jung;Park, Hyeong-Sik
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.7
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    • pp.7-14
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    • 2009
  • In this paper, the effects of annealing conditions on the structural ((002) intensity, FWHM, d-spacing, grain size, (002) peak position), optical (UV peak, UV peak position) and electrical properties (carrier concentrations, resistivity, mobility) of ZnO films were investigated. ZnO films were deposited onto SiO$_2$/si substrates by RF magnetron sputtering from a ZnO target. The substrate was not heated during deposition. ZnO films were annealed in temperature ranges of $500\sim650^{\circ}C$ in the O$_2$ flow for 5$\sim$20 min. The film average thicknesses were in the range of 291 nm. The surface morphologies and structures of the samples were characterize by SEM and XRD, respectively. The optical properties were evaluated by photoluminescence (PL) measurement at room temperature (RT) using a He-Cd 325 nm laser. As the annealing temperature and time vary, the following relations were also observed: (1) proportional relationships among UV intensity (002) intensity, and grain size exist, (2) UV intensity is inversely proportional to FWHM, (3) there is no special relationship between UV intensity and electron carrier concentrations, (4) d-spacing is inversely proportional to (002) peak position, (5) UV peak position in the range of 3.20$\sim$3.24 eV means that ZnO films have a n-type conductivity which was consistent with that obtained from the electrical property, (6) the optimal conditions for the best optical and structural characteristics were found to be oxygen fraction, (O$_2$/(O$_2$+Ar)) of 0.2, RF power of 240W, substrate temperature of RT, annealing condition of 600$^{\circ}C$ for 20 min, and sputtering pressure of 20 mTorr.

Mushroom Production Technology with Crop Residues (농산부산물(農産副産物)을 이용(利用)한 식용(食用)버섯 재배(栽培))

  • Cha, Dong-Yeul;Park, Jeong-Sik
    • Applied Biological Chemistry
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    • v.27
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    • pp.47-55
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    • 1984
  • The results of series studies on the ratio of supplements, out-door composting and out-door fermentation induced by using the rice straw as a main substrates at the cultivation of Agaricus bisporus, and the cultivation of Pleurotus ostreatus using the rice straw bundles on its compost are as follows; When rice straw for cultivation of A. bisporus was used as the main substrates in synthetic compost as a carbon source, yields were remarkably high. Fermentation was more rapid than that of barley straw or wheat straw and the total nitrogen content was high in rice straw compost. Use of barley straw compost for cultivation of A. bisporus was shown of low yield compared with rice straw, but when a 50% barley straw and 50% rice straw mixture was used, the yield was almost the same as that using only rice straw. The total organic nitrogen on the compost were shown the positive relation to the yield of A. bisporus, but the ammonium nitrogen negative relation to the mycelial growth and yield of A. bisporus. When rice straw was used as the main substrate for compost media, urea was the most suitable source of nitrogen. Poor results were obtained with calcium cyanamide and ammonium sulfate. When urea was applied three separate times, nitrogen loss during composting was decreased and the total nitrogen content of compost was increased. The supplementation of organic nutrient activated compost fermentation and increased yield of A. bisporus. The best sources of organic nutrients selected were as follows: perilla meal, sesame meal, wheat bran and poultry manure, etc. Soybean meal, tobacco powder and glutamic acid fermentation byproducts which were industrial wastes, could be substituted for perilla meal, sesame meal and wheat bran as organic nutrient sources for compost media. During out door composing of rice straw for cultivation of A. bisporus, using of tuner, composter and tunnel system increased up to 13% of its yield, and also cut down 34% of production Cost. The cultivation of P. ostreatus and utilizing of rice straw and wheat straw was established and its yield was high on the rice straw pots. When the substrates 'Rice straw' was heated by steam at $60^{\circ}C$ for 6 hr. mycelial growth of P. ostreatus was moderately rapid and its yield was high.

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Effect of Lipid on the Protein Denaturation in Cooking Fish Meat (어육 조리시 지질이 단백질 변성에 미치는 영향)

  • LEE Kang-Ho;CHOI Byeong-Dae;RYU Hong-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.19 no.5
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    • pp.493-501
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    • 1986
  • The present work aims to estimate the effect of heat treatment on the in vitro protein digestibility and formation of trypsin inhibitor or trypsin indigestible substrate(TIS) of raw and defatted flounder. It was also carried out to assess the formation of lipid-protein complexes under the conditions of different ratio of lipid addition. The in vitro protein digestibility increased when steamed for 5 min showing $88.09\%$ in raw and $90.56\%$ in defatted samples, respectively. After 40 min steaming, the digestibility decreased by $2{\sim}4\%$. As for microwaving, heating for 1 min resulted in slight increase of digestibility, however, heating for 7 min did decrease of digestibility by $3{\sim}4\%$ for both raw and defatted materials. There was no difference in fatty acid composition found with heat treatment. The major fatty acids of flounder meat were $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{20:5},\;C_{22:6}$ and the ratio of the unsaturated to saturated was 67.3:32.6. Fat oxidation and nonenzymatic browning were enhanced by heat treatment and protein solubility decreased necessarily as the brown pigment formation increased. On the other hand, the effects on the digestibility and TIS of the complexes formed from interaction of lipid and myofibrillar or meat protein of flounder were examined. The interaction of protein with lipid was considered to mostly contribute to the drop of digestibility of fish products. The digestibility of myofibrillar protein was $93.72\%$ for flounder, and it generally decreased as the amount of lipid added to protein and reaction time increased. Also mixed and heated samples were more active in digestibility decline than those mixed after heating. The result probably indicated that lipid-protein interaction was involved in the drop of digestibility which coincided with protein denaturation.

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