• 제목/요약/키워드: high-purity

검색결과 1,299건 처리시간 0.044초

졸-겔법에 의한 여러 상의 고순도 Alumina 제조에 관한 연구 (A Study on the Preparation of Various Phase Alumina in High Purity by Sol-Gel Method)

  • 황규민;박승수;이희철
    • 대한화학회지
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    • 제33권2호
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    • pp.263-270
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    • 1989
  • 금속알루미늄 조각과 alcohols을 반응시켜 Al-alkoxides를 합성하였으며 이것을 가수분해하여 얻은 Al-hydroxides와 시약 AlCl3로부터 얻은 Al-hydroxides를 여러 온도에서 소성하여 여러 상의 고순도 $Al_2O_3$를 제조하였다. 제조한 ${\gamma}$${\eta}$상 알루미나의 촉매적 특성을 알아보았고, $Al(OH)_3$로부터 ${\alpha}-Al_2O_3$의 생성과정을 속도론적으로 고찰하였다.

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Mineralogical Analysis and Mechano-Chemical Purification of Natural Silica Ore for High Purity Silica Powder

  • Park, Jesik;Lee, Churl Kyoung;Lee, Hyun-Kwon
    • 한국재료학회지
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    • 제26권6호
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    • pp.306-310
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    • 2016
  • To produce 4N grade high-purity silica powder from natural ore, the mineralogical characteristics of natural silica ore were investigated and their effects on the purification process were revealed. The Chinese silica mineral ore used was composed of iron and aluminum as main impurities and calcium, magnesium, potassium, sodium, and titanium as trace impurities; these trace impurities generally exist as either single oxides or complex oxides. It was confirmed that liberation and acidic washing of the impurities were highly dependent on the particle size of the ground silica ore and on its mineralogical characteristics such as the distribution and phases of existing impurities. It is suggested that appropriate size reduction of silica ore should be realized for optimized purification according to the origin of the natural silica ore. A single step purification process, the mechano-chemical washing (MCW) process, was proposed and verified in comparison with the conventional multi step washing process.

A Comparison of Analytical Methods for the Content and Purity of Cefradine

  • Hyun, Myung-Ho;Jeong, Euh-Duck;Shin, Min-Seob;Jin, Jong-Sung
    • Bulletin of the Korean Chemical Society
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    • 제29권6호
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    • pp.1185-1189
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    • 2008
  • Two HPLC methods such as cefadroxil and cefalexin methods were compared in their performance for the quantitative analysis of the content and purity of $\beta$ -lactamic antibiotic, cefradine, for six bulk drug samples. Between the two methods, the cefadroxil method prescribed by the European Pharmacopoeia (EP) for the determination of impurities in cefradoxil was superior to the cefalexin method prescribed by the EP and by the United States Pharmacopeia (USP) for the determination of cefalexin impurity in cefradine in terms of the greater stability of the chromatogram baselines and the higher precision, i.e., the lower % relative standard deviation (RSD). Based on the comparison of the two HPLC methods, the cefadroxil method was recommended to replace the TLC method, which has been prescribed by the EP as the official method for determination of extraneous impurities in cefradine.

Ethyl Silicate를 고순도 $\beta$-SiC미분말 합성에 관한 연구(I) 반응조건과 $\beta$-SiC의 생성율 및 특성 (A Study on Synthesis of High Purity $\beta$-SiC Fine Particle from Ethylsilicate(I) -Reaction Conditon, Yeild and Properties of $\beta$-SiC-)

  • 최용식;박금철
    • 한국세라믹학회지
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    • 제25권5호
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    • pp.473-478
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    • 1988
  • In order to obtain the high purity $\beta$-SiC powder that possesses the excellent sinterability and is close to the spherical shape, the carbon black was mixed into the composition of Si(OC2H5)4-H2O-NH3-C2H5OH which the monodispersed spherical fine particles is formed the hydrolysis of Ethylsilicate and the mixture was carbonized under an argon atmosphere. Particle shpae, size and the yield of $\beta$-SiC powder were investigated according to the molar ratio of carbon/alkoxide and variations of reaction temperature and reaction time. The results of this study are as follow ; 1) The yield of $\beta$-SiC gained from the reaction for one hour at 150$0^{\circ}C$ almost got near 100% and the particle size of $\beta$-SiC from the reaction for 15 hrs at 150$0^{\circ}C$ was 0.2${\mu}{\textrm}{m}$ on the average and close to the spherical shape agglomerate state. 2) When the molar ratio carbon/alkoxide is over 3.1 and the reaction occurs at 145$0^{\circ}C$ for 5hrs, the carbon content has not an effect on the kind of crystal of product.

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Solvent/Detergent Inactivation and Chromatographic Removal of Human Immunodeficiency Virus During the manufacturing of a High Purity Antihemophilic Factor VIII concentrate

  • Kim, In-Seop;Park, Yong-Woon;Woo, Hang-Sang;Chong E. Chang;Lee, Soungmin
    • Journal of Microbiology
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    • 제38권3호
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    • pp.187-191
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    • 2000
  • A validation study was conducted to determine the efficacy of solvent/Detergent (S/D) inactivation and Q-Sepharose column chromatographic removal of the human immunodeficiency virus (HIV) during the manufacturing of a high purity antihemopilic factor VIII (GreenMono) from human plasma. S/D treatment using the organic solvent, tri (n-butyl) phosphate, and the detergent, Trition X-100, was a robust and effective step in eliminating HIV-1. The HIV-1 titer was reduced from an initial titer of 8.3 log10 TCID50 to undetectable levels within one minute of S/D treatment, HIV-1 was effectively partitioned form factor VIII during Q-Sepharose column chromatography with the log reduction factor of 4.1 . These results strongly assure the safety of GreenMono From HIV.

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천연가스 개질 방식 중소형 고순도 수소제조 장치 개발 연구 (Study on the development of small-scale hydrogen production unit using steam reforming of natural gas)

  • 서동주;주국택;정운호;박상호;윤왕래
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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    • pp.720-722
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    • 2009
  • This work is mainly focused at developing the hydrogen production unit with the capacity of 20 $Nm^3/h$ of high purity hydrogen. At present steam reforming of natural gas is the preferable method to produce hydrogen at the point of production cost. The developed hydrogen production unit composed of natural gas reformer and pressure swing adsorption system. To improve the thermal efficiency of steam reforming reactor, the internal heat recuperating structure was adopted. The heat contained in reformed gas which comes out of the catalytic beds recovered by reaction feed stream. These features of design reduce the fuel consumption into burner and the heat duty of external heat exchangers, such as feed pre-heater and steam generator. The production rate of natural gas reformer was 41.7 $Nm^3/h$ as a dryreformate basis. The composition of PSA feed gas was $H_2$ 78.26%, $CO_2$ 18.49%, CO 1.43% and $CH_4$ 1.85%. The integrated production unit can produce 21.1 $Nm^3/h$ of high-purity hydrogen (99.997%). The hydrogen production efficiency of the developed unit was more than 58% as an LHV basis.

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