Polyethylene Glycol과 Dextran이 포함된 고분자 수용액의 액-액 상평형

조정모,강춘형 전남대학교 촉매연구소 2000 觸媒硏究 論文集 Vol.21 No.-

The extraction using an aqueous two-phase polymer solution (ATPS) is a promising technique for separation of biologically active materials. Since ATPS contains mainly water, it provides a mild environment to the biological materials so that their biological activities can be preserved during the process. Among the factors that influence the phase behavior of ATPS, the molecular weight distributions(MWD) of the phase forming polymers have long been ignored. With special attention to the effects of MWD of the polymers, the liquid-liquid equilibrium(LLE) phase diagrams of ATPS containing polyethylene glycol(PEG) and dextrin(Dex) are experimentally determined using the gel permeation chromatography(GPC) and the polymer fractionation in the phase separation is observed. Namely, we observe that the MWDs of both polymers in the coexisting phases are different from each other as well as from the original distribution. Furthermore it is found that while the average molecular weight of Dex in the top phase decreases with the increase of the tie-line length(TLL), that of the bottom phase asymptotically approaches that of the original. The continuous dilution method is examined for the complete determination of the phase diagrams.

Dextran-based Hydrogel의 제조 및 특성에 관한 연구

조정모,노선균,강춘형 전남대학교 촉매연구소 2001 觸媒硏究 論文集 Vol.22 No.-

Due to their sensitivity to external condition, adjustable permeability and high water content, hydrogels have widespread applications in medical, pharmaceutical, biochemical and other industrial fields. In this work, the dextran-based hydrogel was prepared by derivatization of polysaccharide with methacryloyl groups followed by polymerization of an aqueous solution of this methacrylated dextral(dex-MA) in presence of an initiator system consisting of potassium peroxydisulfate(KPS ) and N,N,N',N'-tetramethylethylene diamine(TEMED). The hydrogel and dex-MA thus prepared were characterized by 1H NMR, 13C NMR, FT-IR, and gel permeation chromatography(GPC). Degrees of substitution of MA groups in the glucopyranosyl ring(DS) estimated from peak intensities in 1H NMR spectra were found to be comparable with the prescribed values. Furthermore, the liquid-liquid equilibrium(LLE) phase diagrams of dex-MA/poly (ethylene glycol) (PEG)/water systems at 25℃ were experimentally determined for several dex-MAs of different DS. Finally, the swelling behavior of the hydrogels prepared with dex-MA of different DS was characterized by means of the blue-dex solution method as well as the gravimetric method.

상접촉법에 의한 BSA의 역추출 효율 : pH와 염의 효과 Effects of pH and Salts

노선균,김승재,신재순,강춘형 한국공업화학회 2003 응용화학 Vol.7 No.1

In this work, the effects of pH and salt and its concentration in the excess aqueous phase on the back extraction efficiency of BSA(Boivne Serum Albumin) using a reverse micellar system of the organic phase contains AOT(sodium di(2-ethlhexy) and iso-octane, was extensively examined. In this effort, BSA solubilized in the reverse micells by means of the phase-transfer method was back-extracted by bringing an excess aqueous phase into contact, When 1:1 salt such as KCL or NaCl was added, BSA could be effectively back-extracted to the wxcess aqueous phase at a pH higher than its isoelectric point pI.

연구발표초록 - 특강 ( 열역학 )

강춘형 ( Choon Hyoung Kang ) 한국화학공학회 1992 춘계학술발표회 Vol.- No.-

암모니아 재순환 침출공정을 이용한 볏짚의 전처리

강춘형 ( Choon Hyoung Kang ) 한국화학공학회 2009 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.47 No.1

Poly (dimethylsiloxane) - Solvent 계의 역 기체 크로마토그래피 연구

강춘형,조정모 한국공업화학회 1999 응용화학 Vol.3 No.1

In this work, Inverse Gas Chromatography(IGC) at finite concentration is employed for the study of the interaction characteristics of poly (dimethylsiloxane) (PDMS) with various solvents such as water, ethanol, and iso-propanol. By measuring the specific retention volumes of the probes, the interaction parameters are calculated using the Flory-Huggins equation. From the results, the interaction parameters of the probes are, as expected due to the hydrophobicity of the polymer, found to be of large positive values(2$lt;x$lt;5). With the increase of alkyl chain length of the solvents, the interaction parameter decreases implying the relative favorite interaction with the PDMS. The IGC study is repeated for the cross-linked PDMS, which is prepared in our lab. By measuring the specific retention volumes of the probes, the cross-linking density is found to be about 2.0×10^(-3) mol/g according to the Flory-Rehner equation.

A Study on Prioritization of Urban Forest Composition Using Needs Analysis - Targeting Paju Heyri Village

Kang, Byong-Rho,Koo, Ja-Houng,Kim, Hyoung-Tae,Woo, Jong-Choon Institute of Forest Science 2018 Journal of Forest Science Vol.34 No.1

This study proposes a strategy for the creation and management of urban forests in Paju Heyri art village. Urban forest composition attributes (4 categories and 16 items) were extracted and the questionnaire was asked to the level and the current level for tourists, local residents and workers in Paju Heyri art village. And the priority order for the creation of urban forests was derived through the difference between the present level (performance) and the required level (importance) and the requirements analysis procedure. In this study, the priorities of each item of urban forest formation attributes were determined. The t-test alone had limitations, so we calculated the Borich needs which were not covered by the existing Importance - Performance Analysis (IPA). We used the Locus for Focus Model, which is a method for visually confirming the difference between the current level and the required value for the required level in the 4-quadrant coordinate plane. The results of this study show that the seven priorities can be used as a useful tool for the formulation of urban forests and operational strategies and can be a basic research for the activation of urban forests in the future.

A New Waxy Wheat Cultivar "Sinmichal"

Choon Ki Lee,Moon Seok Kang,Kwang Geun Park,Bon Cheol Koo,Hwa Young Heo,Hyoung Ho Park,Jae Chul Kim,Jung Hyun Nam,Jae Hwan Seo,Hyun Tae Kim,Young Seok Yun,Jung Bae Kweon,Young Woong 한국육종학회 2003 한국육종학회지 Vol.35 No.5

Type 1 삼성분계 액액평형의 임계점 추산방법

강춘형 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.2

Type 1인 삼성분계 액액평형의 임계점을 추산하기 위한 새로운 방법을 제안한다. 일반적으로 열역학 model을 이용하여 대응선을 상관 관계시킨 결과로부터 추산한 임계점은 실험적으로 결정한 용해도 곡선위에 위치하지 않는다. 또 상관 관계식을 이용하는 경우에는 대응선뿐만 아니라 용해도 곡선의 data도 필요하게 된다. 본 연구에서 제안한 방법에서는 대응선 길이의 대수값과 임계점까지의 거리의 대수값의 관계가 Widom의 order parameter식을 만족할 때까지 추정한 임계점에서의 한 성분의 중량분율과 나머지 두 성분의 중량분율비를 변화시킨다. 이 방법으로 여러 삼성분계의 임계점을 추산하였으며, 그 결과들은 Treybal 등의 방법을 이용하여 얻은 결과와 비슷한 만족도를 보였다. 그러나, 이 논문에서 제안한 방법에서는 대응선 data만을 사용하는 반면에 Othmer와 Tobias의 상관 관계식을 이용한 Treybal 등의 방법을 사용하기 위해서는 대응선 data뿐만 아니라 용해도 곡선 data도 필요하다는 것을 강조할 필요가 있다. To estimate plait points of ternary liquid-liquid equilibria(LLE) of type 1, a novel method is proposed. In general, the plait points resulting from correlation of the tie lines with the thermodynamic models are not located on the experimentally determined binodal curves. In addition, determination of the plait points using the correlation methods requires binodal curve data as well as the tie line data. In the proposed method, two parameters, weight fraction of a component and the ratio of weight fractions of remaining two components, are varied until linearity between logarithmic tie-line length and logarithmic distance of the tie-line from the plait point is attained so that the order parameter equation of Widom is satisfied. With this method, plait points of several ternary systems are estimated and it turns out that the results are favorably comparable with the results obtained by the method proposed by Treybal et al. However, it needs to emphasize that the method proposed in this paper uses only tie-line data while the method of Treybal et al. with the correlation of Othmer and Tobias requires experimental binodal curve data in addition to the tie-line data.

공비혼합물을 형성하는 삼성분계의 액 - 액 평형

강춘형 한국화학공학회 1995 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.33 No.2

Entrainer로써 각각 ethyl acetate, N-propyl acetate, N-butyl acetate를 포함하며 공비혼합물을 형성하는 물-초산-entrainer의 삼성분계에 대하여 25℃와 40℃에서 적정법과 cross-section method를 이용하여 용해도 곡선과 tie-line을 결정하였다. 또 이들 액-액 평형 실험결과들을 UNIQUAC model을 이용하여 잘 correlation할 수 있었고 물과 초산의 이성분계짝의 UNIQUAC parameter들은 entrained의 종류에는 별 영향이 없으나 상분리가 일어나는 온도에는 민감함을 보였다. For the azeotropic ternary systems which contain water, acetic acid, and either ethyl acetate, or N-propyl acetate, or N-butyl acetate as the entrainer, the binodal curves and the tie-lines are, respectively, determined using the titration method and the cross-section method at 25℃ and 40℃. With the UNIQUAC model, these experimental equilibrium data are correlated with good accuracy. The UNIQUAC parameters for the binary pair of water and acetic acid are almost entrainer-independent. However those model parameters appear to be influenced by the temperature of phase separation to a considerable extent.