• Title/Summary/Keyword: 시료준비

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Evaluation of Long-Term Deformation Prediction Model on Frozen Sand Considering Fine Contents (세립분 함량을 고려한 동결 사질토의 장기변형 예측 모델 평가)

  • Hwang, Bumsik;Chae, Deokho;Cho, Wanjei
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.1
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    • pp.93-103
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    • 2017
  • Many countries are interested in the development of the Antarctic area because of the abundant resources and living things of high research value. Korea completed the second Antarctic research station in 2014 and spurring the development of the Antarctic area by constructing runway for the airplanes and a third Antarctic research station. However, frozen soils, unlike typical soils, are sensitive to creep behavior due to the influence of ice and unfrozen water. The creep tests for evaluating creep behaviors on the frozen soils require expensive laboratory equipments and large amount of time. Thus, various empirical models had been developed to describe the unconfined compressive creep behavior of frozen soils. In this study, new analytical creep model on frozen sands was proposed by modifying Ting's Tertiary creep model with a new parameter considering fine contents. Thus, the unconfined compressive creep tests were conducted with the frozen specimens of dense Jumoonjin sand with fine contents of 0, 5, 10 and 15% under various loads at -$5^{\circ}C$, -$10^{\circ}C$ and -$15^{\circ}C$. Consequently, the modified Tertiary creep model with a new parameter for fine contents are not enough for the description of the acutal creep behavior of the frozen sand and new framework should be developed.

Effects of Irradiation on Color Values of Food Colorants (감마선 조사가 식용색소의 색도에 미치는 영향)

  • Kim Byeong-Keun;Lim Sang-Yong;Song Hyun-Pa;Chung Jin-Woo;Sung Bo-Kyung;Kim Dong-Ho
    • Food Science and Preservation
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    • v.13 no.1
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    • pp.115-118
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    • 2006
  • As a study on the physico-chemical stability of irradiated food and cosmetics, the effect of gamma irradiation on the color values of some food colorants was evaluated. Amaranth, Fast Green FCF, and Indigo Carmine solutions were prepared with different concentration (0.01 and $0.10\%$), gamma irradiated (0.25, 0.5, 1 and 3 kGy), and then Hunters color (L, a, b, ${\Delta}E$) values were determined. The. gamma irradiation process induced decoloration of the coloring agents. In particular, $0.01\%$ solution showed significant differences in the overall color difference$({\Delta}E)$. The lightness (L value) of Amaranth and Indigo Carmine was increased in proportion to irradiation dose, and their redness (a value) and yellowness (b value) also were increased. The redness (a value) and yellowness (b value) of Fast Green FCF $(0.01\%)$ were increased by gamma irradiation. However, there were no significant spectroscopic differences in $0.10\%$ concentrations of the samples.

Direct Conversion of L-Selenomethionine into Methylselenol by Human Cystathionine ${\gamma}$-Lyase (인간 Cystathionine ${\gamma}$-Lyase에 의한 Selenomethionine의 Methylselenol로의 직접분해)

  • Cho, Hyun-Nam;Jhee, Kwang-Hwan
    • Microbiology and Biotechnology Letters
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    • v.42 no.1
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    • pp.11-17
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    • 2014
  • Selenium is an essential trace element for mammals, but it is very toxic. Therefore, the control of selenium concentrations should be precisely and effectively monitored. Selenium is naturally obtained through foods and seleno-L-methionine (LSeMet) is a major form of selenium. It has been reported that L-SeMet is only converted into Se-adenosyl-L-SeMet. However, a recent study suggested that L-SeMet was directly metabolized into methylselenol ($CH_3SeH$) in mouse liver extract by the reaction of cystathionine ${\gamma}$-lyase (CGL). The canonical reaction of CGL was known to catalyze the cleavage of L-cystathionine to L-cysteine, ${\alpha}$-ketobutyrate and $NH_3$. In the present study, we found that L-SeMet could be directly converted to $CH_3SeH$ using purified homogenous human CGL instead of mouse liver cytosol. Authentic $CH_3SeH$ was prepared by reduction of dimethyldiselenide with sodium tetrahydroborate. The gaseous product of the enzymatic reaction with L-SeMet was analyzed by GC/MS spectrometry. The GC/MS data was identical to that of authentic dinitrophenyl selenoether. We also analyzed the kinetic parameters for the formation of $CH_3SeH$ from L-SeMet by human and mouse CGL. These results suggest that human CGL is a critical enzyme which is responsible for L-SeMet metabolism.

Isolation of Bacteria with Protease Activity from Cheonggukjang and Purification of Fibrinolytic Enzyme (청국장으로부터 혈전용해 활성이 우수한 균주 분리 및 혈전용해효소정제)

  • Choi, Yeon Hee;Lee, Jun Seung;Bae, So Young;Yang, Keun Jae;Yeom, Kyu Won;Jo, Dong Hyeok;Kang, Ock Hwa;Baik, Hyung Suk
    • Journal of Life Science
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    • v.23 no.2
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    • pp.259-266
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    • 2013
  • To isolate the fibrinolytic enzyme, 268 strains from 21 samples were morphologically isolated from Cheonggukjang collected from Korea and Japan. Among the 268 strains, protease-producing bacteria were isolated in nutrient agar medium including 1% skimmed milk. As a result of this, 22 strains were isolated. Apiweb site was used to identify these strains based on their biochemical properties. In addition, 16S rRNA sequencing was performed to identify the strain. Most of the identified strains were Bacillus subtilis and B. amyloliquefaciens. Fibrinolytic enzyme activity was measured with the fibrin plate method. Five strains were finally selected: A2-14, A2-20, C1-05, C1-09, and F2-01. Of those five strains, the A2-20 strain, which is close to B. amyloliquefaciens, showed the strongest fibrinolytic activity. The fibrinolytic enzyme produced by the A2-20 strain was partially purified from culture supernatant by gel filtration and ion exchange chromatography. The optimal pH and temperature values of the partially purified enzyme were 7.0 and $35^{\circ}C$, respectively. Purified protein analysis was carried out with SDS-PAGE and zymography. A genetic analysis was also conducted by PCR based on the consensus sequence of fibrinolytic enzyme. Corresponding genes with a partial sequence of the A2-20 strain were identified.

Effect of Amino acids on the Oxidation of Linoleic acid (일부 아미노산이 Linoleic acid의 산화반응에 미치는 영향)

  • Lee, Joon Ho;Lee, Eun Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.12 no.4
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    • pp.336-341
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    • 1983
  • A study on the oxidation effect of some amino acids(glutamic acid, phenylalanine, alanine) addition to the linoleic acid emulsion was conducted. Amino acid solutions in concentrations of $10^{-2}$, $10^{-3}$ and $10^{-4}M$ were mixed with equal volume of linoleic acid emulsions. The prepared samples were incubated at $60{\pm}1^{\circ}C$ and the extent of diene conjugation and TBA values were measured by using the UV visible spectrophotometer. The results were as follows: 1) From the extent of diene conjugation, we found that the addition of phenylalanine and alanine prolonged the induction period and the addition of glutamic acid shortened. There was an optimum concentration for each amino acid to act as an antioxidant during the induction period. The optimum concentration of alanine was $10^{-3}M$ and that of phenylalanine was $10^{-2}M$. 2) The results of TBA values showed that three amino acids possesed antioxidant activity after the induction period. There was also an optimum concentration to act as antioxidant after the induction period. The optimum concentrations of glutamic acid, phenylalanine, and alanine were $10^{-2}$, $10^{-3}$, and $10^{-3}M$, respectively.

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Comparison of Shear Bond Strength of Veneer Ceramics to Co-Cr Alloys Produced by Selective Laser Melting and Casting Technique (선택적 레이저 용융 그리고 전통적인 주조 기술에 의해 제조된 Co-Cr 합금에 대한 전장용 세라믹의 전단 결합 강도 비교)

  • Hong, Min-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.434-439
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    • 2020
  • Selective laser melting (SLM) manufactures an alloy using laser as a heat source, and has recently been introduced in the dental industry. However, there is a lack of analytical research on metal-ceramic restorations achieved by SLM. This study evaluates and compares the metal-ceramic bond strength of Co-Cr alloys produced by selective laser melting and casting methods. Co-Cr samples required for this study were produced through the sintering process of ceramics, by applying the SLM and CAST methods. The metal-ceramic bond strength was measured by applying the shear bond strength test. In order to determine the area fraction of adherent ceramic, Si content of the specimen was measured using scanning electron microscopy SEM/ EDS. Results of the metal-ceramic bond strength and AFAC were analyzed by t-test (α = 0.05). No significant difference was observed comparing the bond strength of SLM and CAST Co-Cr alloys (P> 0.05). However, the SLM group had much better ceramic adherence than the CAST group (P < 0.001). Moreover, oxidation characteristics were similar for both SLM and CAST Co-Cr alloys, but metal structures were different. These results imply that although the bond of ceramic and Co-Cr alloy is not related to the manufacturing method, SLM alloys impart better ceramic adherence. This indicates that alloys made with SLM can be used to fabricate upper implant prostheses in the future. In particular, it is expected to overcome the shortcomings of the CAST method, and save time and cost.

The Isolation of Agarolytic Agarivorans sp. HY-1 and the Characterization of Its Agarase (한천분해 Agarivorans sp. HY-1의 분리와 한천분해효소의 특성)

  • Lee, Dong-Geun;Cho, Ha-Yeon;Kim, Andre;Lee, Sang-Hyeon
    • Journal of Life Science
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    • v.32 no.4
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    • pp.285-289
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    • 2022
  • In this study, the growth characteristics of an agar-degrading bacterium isolated from seawater samples collected from Yeongheungdo, Incheon, and the characteristics of its agarase were analyzed. The 16S rRNA gene sequence of the isolated strain was 95% similar to that of the genus Agarivorans, and thus the isolated strain was named Agarivorans sp. HY-1. When Agarivorans sp. HY-1 was cultured in a marine broth 2216 medium at 27℃ and 250 rpm, it showed maximum growth on day 1 and showed maximum enzymatic activity on day 2. A crude enzyme solution was prepared from secreted agarase in the culture medium. The extracellular agarase of the Agarivorans sp. HY-1 strain showed maximal activity at 40℃ and pH 7.0 (20 mM Tris-HCl) with 591.91 U/l. The agarase exhibited relative activities of 64, 91, 100, 97, 89, and 60% at 20, 30, 40, 50, 60, and 70℃, respectively. At pH 5, 6, 7, and 8, the relative activities were 79, 95, 100, and 55%, respectively. Furthermore, the agarase exhibited >86% residual activity at 20, 30, and 40℃ for 2 hr and >44% residual activity at 50℃ after 2 hr. A TLC analysis confirmed that Agarivorans sp. HY-1 produced α-agarase. As the degradation products of α-agarase have anticancer and antioxidant effects, Agarivorans sp. HY-1 and its agarase may well prove useful.

Analysis of Taste Compounds in Traditional Korean Soy Sauce by Two Different Fermantation Jars (담금용기에 따른 한국 전통 간장의 맛 성분 분석)

  • Park, Ok-Jin;Sohn, Kyung-Hee;Park, Hyun-Kyung
    • Journal of the Korean Society of Food Culture
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    • v.11 no.2
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    • pp.229-233
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    • 1996
  • This study was carried out to analyze the changes in nitrogen compounds, free-amino acids and volatile organic acids of traditional Korean Soy Sauce with two different fermentation jars and varying Meju concentration. Total nitrogen content in the glass jar was higher than that of the clay jar. However, the glass jar contained more nitrogen in ammonia type nitrogen and less in amino type nitrogen than clay jar, resulting in inferior quality. Total free amino acids content was highest on the 150th day. Among free amino acids, the concentration of glutamic acids, aspartic acid, serine, alanine and lysine, which give sweet and savory taste, were higher than that of the others. Phenylalanine, valine, leucine and isoleucine, which give bitter taste, were also present in significant quantities. Among identified volitile organic acids, acetic acid was present in the hightest concentration, and it's concentration was higher in the jar than in the glass jar. Meju concentration 1:4 showed slow increse while 1.3:4 showed similar trends in the glass jar 1:4 and clay jar 1.3:4, and it's concentration decreased after the ripening period in all samples. In addition valerie acid and capric acid were also present in small quantities.

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Geochemical Characteristics of the Hydrocarbons from the Block 6-1, Ulleung Basin (울릉 분지 6-1 광구에서 발견된 탄화수소의 지화학적 특성)

  • Lee, Young-Joo;Cheong, Tae-Jin;Oh, Jae-Ho;Park, Se-Jin;Yi, Song-Suk
    • The Korean Journal of Petroleum Geology
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    • v.11 no.1 s.12
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    • pp.1-8
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    • 2005
  • Seventeen exploratory wells have been drilled in the Block VI-1 of offshore Korea, which is located in the southern part or the Ulleung Basin. Gas show has been recognized from most of the wells, and gas and condensate have been accompanied in some wells. Commercial discovery of gas, accompanied by condensate, has been made from Gorae V well. The reservoir gases or the Dolgorae III, Gorae I, and Gorae V wells in the Ulleung Basin mainly consists of hydrocarbon gases (>93%). These gases are thermogenic wet gases which contain more than 96% of the methane and result from the cracking of petroleum or kerogen. Based on the chemistry and composition of the gases and stable isotope data, they seem to be generated from different source rocks. The condensates from the Gorae I and V wells are mostly generated from terrestrial organic matter. Lacustrine organic matter may not play an important role for the generation of these condensates. The condensates from the Gorae V wells consist predominantly of terrestrial organic matter but with minor subsidiary input from marine organic matter. The condensates from Gorse I and V wells may be generated from different source rocks. The thermal maturity level of the condensates from the Gorae V well ranges from early to middle oil generation zone and condensate from Gorae I reaches middle oil window. Correlation or the thermal maturation level of the condensates and organic matter in the sediments reveals that a depth of the generation of liquid hydrocarbons can be inferred to 3,000 m and 3,900 m for the Gorae V and I wells, respectively. Gorae V well, however, did not reach the target depth and the geochemical data of the Gorae I well were obscured due to the severe sediment caving in.

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Analysis of Indicator Microorganism Concentration in the Rice Cultural Plot after Reclaimed Water Irrigation (하수처리수 관개후 벼재배 시험구에서 지표미생물 거동 분석)

  • Jung, Kwang-Wook;Jeon, Ji-Hong;Ham, Jong-Hwa;Yoon, Chun-Gyeong
    • Korean Journal of Ecology and Environment
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    • v.37 no.1 s.106
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    • pp.112-121
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    • 2004
  • A study was performed to examine the effects of UV-disinfected reclaimed water on microorganism concentration during rice culture. Four treatments were used and each one was triplicated to evaluate the changes of microorganism concentrations: stream water irrigation (STR), biofilter effluent irrigation (BE), UV-disinfected water irrigation with dose of 6 mW ${\cdot}$ s $cm{-2}$ (UV-6), and UV-disinfected water irrigation with dose of 16 mW ${\cdot}$ s $cm{-2}$ (UV-16). The indicator microorganisms of interest were total coliform (TC), fecal coliform (FC), and E. coli. The biofilter effluent from 16-unit apartment sewage treatment plant was used as reclaimed water and flowthrough type UV-disinfection system was used. Concentrations of indicator microorganisms in the treatment plots ranged from $10^2$ to $10^5$ MPN/100 mL during 24 hours after irrigation in May and June, where initial irrigation water for transplanting reparation was biofilter-effluent without UV-disinfection. It implies that initial irrigation using only non-disinfected reclaimed water for puddling in paddy field can be health-concerned because of more chance of farmer's physical contact with elevated concentration of microorganisms. The concentrations of microorganisms varied widely with rainfall, and treatments using UV-disinfected water irrigation showed significantly lower concentrations than others and their levels were within the range of paddy rice field with normal surface water irrigation. The mean concentrations of STR and BE during growing season were in the range of 4 ${\times}\;10^3$ MPN/100 mL for TC, and 2${\times}\;10^3$ MPN/100 mL for FC and E, Coli, While mean concentrations of UV-S and UV-lS were less than 1${\times}\;10^3$ MPN/100 mL for all the indicator microorganisms. Overall, UV-disinfection was thought to be feasible and practical alternative for agricultural reuse of secondary level effluent in Korea.