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Characteristics of Dental Restorative Composite Resins Prepared from 2,2-bis- [4- (2-hydroxy-3-rnethacryloyloxy propoxy) phenyl] propane Derivatives and Spiro Orthocarbonate (2,2-비스[4-(2-하이드록시-3-메타크릴로일옥시프로폭시)페닐] 프로판 유도체와 스파이로 오쏘카보네이트가 포함된 치아 수복재의 특성)

  • Kim Yong;Lee Juyeon;Park Kwangyong;Kim Chang Keun;Kim Ohyoung
    • Polymer(Korea)
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    • v.28 no.5
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    • pp.426-432
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    • 2004
  • To reduce volumetric shrinkage of the commercially available polymeric dental composite during curing reaction, (2,2-bis [4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane) (bis -GMA) derivatives, i.e., (2,2-bis[3-methyl, 4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propan) (DMBis-GMA) and (2,2-his [3,5-dimethyl ,4- (2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane) (TMBis-GMA) were synthesized and then new dental composite resin composed of Bis-GMA derivatives, diluent, spiro orthocarbonate (SOC), and inorganic filler was produced. Among the Bis-GMA derivative/Bis-GMA derivative/diluent mixtures, Bis-GMA/ TMBis-GMA/TEGDMA mixture exhibited the lowest volumetric shrinkage. Volumetric shrinkage of this mixture was further reduced by adding SOC. Volumtric shrinkage of dental composite prepared from commercially available resin monomer mixture was $2.5\%$, while that prepared from resin monomer mixture having minimum volumetric shrinkage was reduced to $0.7\%$. Mechanical strength of this dental composite was nearly the same with that of commercial products but the time required for the curing reaction was retarded.

A study on the removal characteristics of bisphenol in water by coagulation (응집에 의한 Bisphenol A의 제거특성)

  • Park, Jihyun;Shin, Daeyewn;Park, Sunku
    • Analytical Science and Technology
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    • v.19 no.2
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    • pp.181-187
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    • 2006
  • This study was carried to survey the removal characteristics of BPA using coagulation process by PAC and PAHCS. BPA removal for PAC and PAHCS was 20.4 with 8.7 Al mg/L and 6.8 Al mg/L, respectively. Removal of BPA was lower than $UV_{254}$ and DOC but removal characteristics were similar. BPA removal for PAC and PAHCS was most high in pH 6.5 and 7.0 respectively. The time for removal by mixing time was 40 min in PAC and 30 min in PAHCS. When powdered activated carbon 50 mg/L was added in coagulation process, a high remove of BPA (61%) was noticed. Specially BPA was highly increase powdered activated carbon 5 mg/L alone. These results will be appliable in the conventional water treatment plants for improvement of water treatment system.

Quality and Antioxidant Properties of Tofu Coagulated with 'Tsugaru' Apple (Malus domestica Borkh) Juice (쓰가루 사과즙을 이용한 두부의 품질 및 항산화 특성)

  • Kim, Dong-Ho;Hong, Kyeong-Nam;Lim, Yeo-Kyeong;Cha, Seung-Hyeon;Ryu, Ji-Eun;Cho, Jin-Ho;Kim, Dae-Il;Yoo, Do-Il;Jang, Keum-Il
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.8
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    • pp.1130-1137
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    • 2016
  • In this study, we investigated the quality, antioxidant properties, and sensory characteristics of tofu coagulated with 'Tsugaru' apple (Malus domestica Borkh) juice. Yield, $^{\circ}Brix$, pH, total acidity, total polyphenol content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 'Tsugaru' apple juice were 60%, 10.3, 3.89, 0.51%, 2.26 mg gallic acid equivalent (GAE)/g, $20{\mu}g$ L-ascorbic acid equivalent (AE)/g, and $75{\mu}g$ AE/g, respectively. In case of Tofu coagulated with 20% (w/v) 'Tsugaru' apple juice, yield, $^{\circ}Brix$, pH, total acidity, hardness, chewiness, cohesiveness, total polyphenol content, ABTS radical scavenging activity, and DPPH radical scavenging activity were 165%, 6.23, 0.27%, 513 g, 315, 0.61, 12.04 mg GAE/g, $80.67{\mu}g$ AE/g, and $92.32{\mu}g$ AE/g, respectively. Both the manufacture yield and pH of tofu decreased with increasing amount of 'Tsugaru' apple juice, whereas total acidity increased. Regarding the texture and chromaticity of tofu coagulated with increasing amounts of 'Tsugaru' apple juice, hardness, chewiness, and a- and b-values increased, whereas cohesiveness and L-value both decreased. In terms of antioxidant activities, total polyphenol content and DPPH radical scavenging activity increased, whereas ABTS radical scavenging activity was maintained within a certain range. Finally, concerning the sensory evaluation (taste, color, flavor, and overall preference) of tofu coagulated with 30% (w/w) 'Tsugaru' apple juice showed the highest scores. Taken together, these results support the possible use of 'Tsugaru' apple juice in producing various foods, as addition of juice enhanced quality, antioxidant properties, and sensory characteristics of tofu.

Processing of Leaflike and Powder Tea Using Sea Tangle (다시마를 이용한 엽상 및 분말차 개발)

  • 배태진;곽지만;김해섭;김귀식
    • Journal of Life Science
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    • v.12 no.1
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    • pp.16-25
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    • 2002
  • To summarize our interpretation of the results, we can explain shown below. Optimum con dictions in order to soften of sea tangle leafs were treated in the solutions of 0.05% $CH_3$COOH at 9$0^{\circ}C$ for 0.5 hour, 0.2% $K_2$HPO$_4$at 10$0^{\circ}C$ for 0.5 hour and 0.3% NaHCO$_3$at 10$0^{\circ}C$ for 0.5 hour. After sea tangle leafs were treated in the solutions of 0.05% $CH_3$COOH at 9$0^{\circ}C$ for 0.5 hour and added 10% seasoning agent of 0.5% glutamic acid, 3% glycine, 5% sorbitol and 1.5% soy sauce. Contents of free amino acid in the leaflike tea were a large amount as alanine of 707.2 $\mu$mo1/100$m\ell$ and glutamic acid of 343.6 $\mu$mo1/100 $m\ell$. And contents of mineral were order Na of 49.38 ppm, Mg of 10.72 ppm, K of 10.56 ppm and Ca of 6.55 ppm. Powder tea was added 0.05% glutamic acid, 5% glycine, 5% glucose and 4% sodium chloride in sea tangle powder, and then pressure treatment at 11$0^{\circ}C$ for 1.5 hours. Contents of free amino acid in the powder tea were a large amount as glycine of 222.04 $\mu$mo1/100$m\ell$ and glutamic arid of 208.58 $\mu$mol/100$m\ell$. And contents of mineral were order Na of 104.24 ppm, Mg of 14.31 ppm, K of 9.68 ppm, Fe of 2.36 ppm, Ca of 2.00 ppm, Zn of 0.13 ppm, Cu of 0.10 ppm and Mn of 0.01 ppm.

Synthesis and Characterization of Layered Copper Hydroxides in Highly Concentrated Solution (고농도 용액에서 Layered Copper Hydroxides의 합성 및 특성)

  • Nam, Dae-Hyean;Choi, Choong-Lyeal;Kim, Kwang-Seop;Seo, Young-Jin;Park, Man
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.872-879
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    • 2010
  • Layered copper hydroxides [LCHs, $Cu_2(OH)_3{\cdot}NO_3$] has the agricultural potentials as a fungicide because of its high crystallinity, excellent anion exchange capacity, and its regular layered particle size. The study, for the first time, has synthesized LCHs in highly concentrated solution and evaluated its physicochemical properties including the crystallinity and suspension stability. Optimal synthetic condition of LCHs was determined by crystallinity and stability of suspension as follow; 1) concentrations of $Cu(NO_3)_2$ and NaOH solutions were 3.0 M respectively, 2) reaction temperature and solution pH were $25^{\circ}C$ and 6.0, respectively, and 3) aging time after reaction was 2hr. Crystallinity of LCHs enhanced with increase in pH up to 9.0. Whereas, stability of suspension was decrease by increase in crystal size. Especially, increase in reaction temperature decreased stability of suspension. XRD patterns and SEM images exhibited that LCHs had regular layered particle size with 0.2~0.8 ${\mu}m$ and high crystallinity in optimal synthetic condition. The particle size was increased with increase in reaction temperature and pH. These results showed that LCHs synthesized in highly concentrated solution exhibited high stability of suspension as well as high crystallinity suitable to their potential as a fungicide.

Microbial Desulfurization of a Bituminous Coal by Iron-Oxidizing Bacteria Thiobacillus ferooxidans (철산화 박테리아 Thiobacillus ferrooxidans에 의한 역청탄의 생물학적 탈황)

  • 류희욱
    • KSBB Journal
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    • v.11 no.2
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    • pp.238-245
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    • 1996
  • Microbial desulfurization characterlstics of a bituminous coal have been determined by using Thiobacillus ferrooxidans. The effects of process variables (such as coal pulp density, particle size and addition of surfactants) on pyrite removal have been investigated in both shake and airlift-bioreactor culture experiments. In shake experiments, pyrite could be removed over 78% for pulp densifies below 20% (w/v) and removed below 40% for pulp densities over 30% (w/v) in 8 days. Pyrite removal decreased with increasing pulp densities, and it also decreased sharply with increasing particle sizes. In airlift bioreactor experiments, pyrite at 50% (w/v) pulp density could be removed about 50%. Its value is much higher than 15% at the same pulp density in a shake experiment. With addition of surfactants, pyrite removal was enhanced in shake experiments significantly, whereas it was slightly decreased in an airlift bioreactor experiment.

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Mass Reduction and Physicochemical Properties of the Produced Compost during Composting Domestic Food Wastes in a Small Composter (소형 퇴비화용기에서 가정 음식물쓰레기의 퇴비화 과정 중 감량화 및 생산 퇴비의 물리화학적 특성)

  • Park, Ju-Won;Seo, Jeoung-Yoon
    • Korean Journal of Environmental Agriculture
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    • v.20 no.4
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    • pp.238-243
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    • 2001
  • Mass reduction and physicochemical properties of the produced compost were investigated during composting domestic food wastes without additive. A small composter used in this study had the height of 15 cm from the center of bottom half circle (diameter 24 cm) up to under the lid, the side length of 50 cm and the horizontal lid angle of $50^{\circ}$ and was operated at the heating unit temperature of $85^{\circ}$. It was mixed by the rotating arm for two minutes in every half hour while supplied with air flow at 3 L/min for 10 minutes in every half hour. This condition was found in a preliminary experiment as optimal for keeping the water content of composting material in the optimal range without adding any bulking materials. The domestic food wastes were added into the composter at the rate of 1 kg/day without additives during composting. The results were as follows; during the composting process, water content maintained in the range of $51.0{\sim}53.5%$. Hemicellulose and lignin contents did not show any tendency, but cellulose content decreased. During the composting process, $NH_3-N$ and $NO_2-N$ were not detected due to nitrification. The contents of inorganic compounds did not increase during the composting process. They were in the range of $1.32{\sim}1.71%\;P_2O_5$, $1.29{\sim}1.48%\;CaO$, $0.41{\sim}0.49%\;MgO$, and $0.38{\sim}0.74%\;K_2O$. For 20 days, weight reduction rate was 67.5% in wet basis, and decomposition rate was 48% in dry basis. Concentration of heavy metals (Cu, Cr, Cd, Pb, Zn, Hg, As) was less than the limiting value of the compost. Maturity of the produced compost was 3 grade through reaching maximum temperature of $46{\sim}48^{\circ}C$.

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Sorptive Removal of Radionuclides (Cobalt, Strontium and Cesium) using AMP/IO-PAN Composites (AMP/IO-PAN 복합체를 이용한 방사성 핵종(코발트, 스트론튬, 세슘)의 흡착 제거)

  • Park, Younjin;Kim, Chorong;Shin, Won Sik;Choi, Sang-June
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.11 no.4
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    • pp.259-269
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    • 2013
  • Applicability of ammonium molybdophosphate/iron oxides-polyacrylonitrile (AMP/IO-PAN) composites on the removal of radionuclides in the radioactive wastewater generated from nuclear power plants was investigated. The composites were characterized using the following analytical techniques: X-ray diffraction (XRD), Fourior transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), particle size analyzer (PSA), nitrogen adsorption-desorption and magnetic property measurement system (MPMS). 10wt% of AMP/IO-PAN composite has a saturation magnetization of 2.038 emu/g. Single-solute sorptions of Co, Sr and Cs onto 10wt% of AMP/IO-PAN composite were investigated. The maximum sorption capacities ($Q^0$) predicted by the Langmuir model on 10wt% of AMP/IO-PAN composite were 0.097, 0.086 and 0.66 mmol/g for Co, Sr and Cs, respectively. The maximum sorption capacities ($Q^0$) of Cs predicted by Langmuir model on 0, 10, 20 and 30wt% of AMP/IO-PAN composites were 0.702, 0.655, 0.602 and 0.559 mmol/g, respectively. The maximum sorption capacities ($Q^0$) of Cs decreased with increasing the iron oxide content in the AMP/IO-PAN composites.

Purification and Utilization of Industrial Waste Water Using Microorganism -(Part 1) Isolation of the yeast strain from organic waste water and its use on waste water treatment- (산업폐수의 처리 및 이용에 관한 연구 -(제 1 보) 효모균주의 분리와 이에 의한 유기성폐수의 처리에 관하여-)

  • Lee, Kang-Heup;Yim, Sung-Sam;Park, Tai-Won
    • Applied Biological Chemistry
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    • v.20 no.2
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    • pp.228-235
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    • 1977
  • The yeast strain was isolated from food industry waste water and its identification and biological characteristics were investigated. The optimum condition for cultivations and its activities for the reduction of B.O.D. on the food industry waste water were also confirmed. The results are as follows; 1) The isolated was identified as Candida curvata. 2) Candida curvata grew well in all of the experimented media, so and it can be regarded as a useful strain in the treatment of food industry waste water. 3) There was only a slight difference in the induction period between sterilized cultivation and unsterilized cultivation. But in the ice cream waste water, the period was considerably longer in unsterilized cultivation. 4) Specific rate of growth of Candida curvata in sugar waste water was 0.50/hr, ice cream waste water 0.50/hr, and beer waste water 1.0/hr. 5) Increasing of innoculum reduced the induction period in unsterilized cultivation. 6) The amount of dried yeast from sugar waste water were $175mg/{\ell}$, ice cream waste water $628mg/{\ell}$, and beer waste water $857mg/{\ell}$. Crude protein content in the dried yeast from sugar waste water were 52%, ice cream waste water 54%, and beer waste water 54%. 7) The rate of BOD reduction in sugar waste water were 49%, ice cream waste water 80%, and beer waste water 64%.

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Effects of Coal Fly Ash on Composting Process of Household Garbage (음식쓰레기 퇴비화 과정에서 석탄회 첨가 효과)

  • Seong, Soon-Hee;Kim, Woo-Seong;Seo, Jeoung-Yoon
    • Korean Journal of Environmental Agriculture
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    • v.15 no.3
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    • pp.282-288
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    • 1996
  • Because of the high water content of the household garbage, it is difficult to compost it. Therefore, this study was conducted to investigate the possibility of using coal fly ash as humidity conditioner for the household garbage composting. The summarized results are as follows : 1. The maximum temperatures were $35^{\circ}C$ in spring, $47^{\circ}C$ in summer, and $43^{\circ}C$ in winter during the composting periods. 2. The mass was reduced to 70.5% after 60 days. The average volume reduced down to 74.7% after 60 days. 3. The seasonal variation of pH values showed a similar tendency and reached 8.5 after 60 days. 4. The water content was reduced at an early stage of composting and not much changed thereafter. It had 49.7% in spring, 33.9% in summer, and 56.5% in winter after 60 days. Ash contents were not much changed during the composting periods. 5. The contents of inorganic compounds were in the range of $0.06{\sim}4.03%$ $P_2O_5$, $0.01{\sim}2.87%$ CaO, $0.18{\sim}1.43%$ MgO, and $0.39{\sim}2.03%$ $K_2O$. Heavy metal contents were in the range of $ND{\sim}14.08$ Hg ${\mu}g/kg$, $ND{\sim}0.80$ Cd mg/kg, $4.99{\sim}28.95$ Cu mg/kg, $ND{\sim}242.62$ Cr mg/kg, $ND{\sim}20.24$ Pb mg/kg, and $ND{\sim}59.87$ Zn mg/kg.

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