• 한국동물학회:학술대회논문집
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• 한국동물학회 1996년도 한국생물과학협회 국제학술대회
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• pp.92.1-92
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• 1996

No Abstract, See Full Text

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.313-314
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• 2005

• 한국광물학회:학술대회논문집
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• 한국광물학회.한국암석학회 2003년도 공동학술발표회 논문집
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• pp.11-14
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• 2003

• 한국재료학회:학술대회논문집
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• 한국재료학회 2002년도 추계학술발표강연 및 논문개요집
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• pp.178-178
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• 2002

• 대한화학회지
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• 제68권3호
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• pp.135-138
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• 2024

• 한국환경생태학회지
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• 제12권2호
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• pp.131-137
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• 1998

공단지역과 일반지역의 대기오염 및 산성비가 수목피해에 미치는 영향을 파악하기 위하여 경남, 울산지역을 중심으로 산림내 유입되는 강우에 대한 오염물질의 이온특성을 분석하고, 대기중 S $O_2$농도와 수목의 쇠퇴도를 비교하였다. 강우의 pH는 공단지역이 일반지역보다 낮아 산성비가 내리고 있었고, EC는 pH와 강한 부의 상관(r=-.7861$^{**}$ )이었다. 용존성분중 양이온과 음이온 농도는 공단지역이 높았으며, 음이온에서는 S $O_{4}$$^{2-}$ 와 N $O_{3}$$^{-}$ 가 높았다. 대기중 S $O_2$농도는 공단지역이 높고, 계절별로는 겨울과 봄이 높았다. 수목쇠퇴와 변수들의 상관분석결과 편상관계수는 S $O_{4}$$^{2-}$ ＞ pH ＞ EC(Electrical conductivity) ＞ N $O_{3}$$^{-}$ ＞ S $O_2$＞ C $l^{-}$ 순이었으며, 추정회귀식은 Y = 5.1007-0.7811 $X_2$(pH) + 0.0253 $X_{5}$ (S $O_{4}$$^{2-}$ ) + 0.0275 $X_{6}$(NON $O_{3}$$^{-}$)로서, 대기오염과 산성비가 함께 영향을 미치는 것으로 나타나 산림생태계 쇠퇴 및 토양산성화는 계속될 것으로 생각된다.

• 대한수의학회지
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• 제33권3호
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• pp.393-406
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• 1993

Antibacterial substances produced by Lactobacillus casei subsp. and Streptococcus faecium were examined for its antibacterial effects against some pathogenic bacteria. They were partially purified with ammonium sulfate precipitation, methanol-acetone extraction, G-50 gel filtration and examined its characteristics. When L casei subsp. and Str faecium were cultivated in MRS broth, stationary phase of L casei is until 24 hours and Str faecium is 20 hours. pH change of the cultured medium was both decreased after 12 hours and then constant at pH 4.5~4.6 after 28 hours. MRS broth culture fluids of L casei subsp. and Str faecium appeared the antibacterial effects by the spot-on-the-lawn method against ETEC, Sal pullorum and Sta aureus. Culture filtrates of L casei subsp. and Str faecium also appeared the antibacterial effects by the disc diffusion method. Culture filtrates of L casei sub. rhamnosus 7469 produced 0.032M of lactic acid and 0.01M of acetic acid. Str faecium 27273 also produced 0.027M of lactic acid and 0.01M of acetic acid. Protein concentrations of culture filtrates produced by L casei sub rhamnosus 7469 and Str faecium 27273 was $495{\mu}g/m{\ell}$ and $594{\mu}g/m{\ell}$, respectively. Antibacterial substances which are partially purified by ammonum sulfate precipitation, methanol-acetone extraction and G-50 gel filtration inhibit the growth of ETEC, Sal pullorum and Sta aureus. Characteristics of purified antibacterial substances was examined. Its molecular weight was about 31Kd, stabilized at $100^{\circ}C/20min.$ and some of proteolytic enzyme treatment.

• Translational and Clinical Pharmacology
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• 제26권3호
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• pp.134-140
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• 2018

This study aimed to develop a UPLC-MS/MS method for determining plasma levels of L-aspartic acid and L-asparagine and the activity of L-asparaginase. L-aspartic acid, L-asparagine, and L-aspartic acid-2,3,3-$d_3$ were extracted from human plasma by protein precipitation with sulfosalicylic acid (30%, v/v). The plasma samples were analyzed using an Imtakt Intrada amino acid analysis column with 25 mM ammonium formate and 0.5% formic acid in acetonitrile as the mobile phase with step gradient method at a flow rate of 0.5 mL/min. The injection volume was $5{\mu}L$, and the total run time was 15 min. Inter- and intra-batch accuracies (%) ranged from 96.62-106.0% for L-aspartic acid and 89.85-104.8%, for L-asparagine, and the coefficient of variation (CV%) did not exceed 7%. The validation results for L-aspartic acid and L-asparagine satisfied the specified criterion, however, the results for L-asparaginase activity assay showed a borderline validity. This study could be a foundation for further development of therapeutic drug monitoring systems using UPLC-MS/MS.

• 대한화학회지
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• 제4권1호
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• pp.44-50
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• 1957

Fibrous cellulose triacetate prepared from purified cotton under various temperatures was dissolved in the solution of 70%, monochloroacetic acid and it was fractionated using water as a precipitant. Eight fractions were obtained through the stepwise precipitation. Degree of polymerization and molecular weight of each fraction were measured viscometrically. Integral and differential molecular weight distribution curve were drawn for each sample prepared under various temperatures and were carefully observed. On this experimental study, following conclusions were obtained: Fractional precipitation can be carried out for fibrous cellulose triacetate in the solution of 70% monochloroacetic acid using water as a precipitant. The differences on the shapes of molecular weight distribution curve were occured on account of the various acetylation temperatures. At the relatively higher acetylation temperatures, the cellulose was randomly degraded and the portion of low degree of polymerization was increased. Commercial acetate, therefore, may not be prepared at above 40$^{\circ}C$ according to the molecular weight distribution curve regardless of higher viscosity and average degree of polymerization. It was concluded that the optimum acetylation temperature for commercial acetate was approximately 30$^{\circ}C$.

• 한국기계가공학회지
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• 제12권2호
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• pp.49-54
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• 2013

Recently welding of aluminum material is actively carried out to make lightweight in the fields of LNG vessels, aircraft, chemical plants, etc. To obtain high strength, hardness and elongation, elements such as manganese, zinc, silicon, etc should be added in aluminum alloy, which has been improved on the mechanical properties like precipitation hardening, age hardening, loosening, corrosion resistance acid resistance. Ar gas is used as a shielding gas of MIG welding for aluminum, also $N_2$, $O_2$, $CO_2$, $H_2$ etc can be added depending on the composition of the alloy. In this study, Ar + $O_2$, Ar, and He were used for welding, hardness, penetration status and changes in composition of penetrated parts were compared and analyzed. This made it possible to know the status and changes of the process in the penetrated parts depending on used gas throughout this study.