• Korean Chemical Engineering Research
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• 제43권2호
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• pp.243-248
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• 2005

분리막 투과증발은 증류에 비하여 낮은 에너지를 요구하기 때문에 물/유기물 혼합물의 분리에 이용될 수 있으며 공비 혼합물이나 이성질체의 분리에 선호되는 방법이다. 제올라이트 분리막은 고분자 분리막에 비하여 열적, 기계적, 화학적 안정성이 우수하며 NaA 제올라이트 분리막은 큰 친수성을 나타내므로 물/유기물 혼합물로부터 효율적인 물 분리에 적합하다. 본 연구에서는 NaA 제올라이트 분리막을 이용한 투과증발 막분리 공정을 이용하여 물/에탄올 혼합물에서 선택적으로 물을 분리하고자 하였다. 에탄올의 공급 농도가 증가함에 따라 총투과플럭스는 감소하였으며 선택도는 증가한 후 높은 에탄올 농도에서 감소하는 것을 관찰할 수 있었다. 실험 온도의 증가에 따라 총투과플럭스는 증가하였으며 선택도 또한 증가하였지만 높은 에탄올 농도에서는 감소하였다. 160시간 이상의 장기간 실험을 통하여 총투과플럭스와 선택도가 안정적으로 일정함을 확인할 수 있었다. 또한, 본 연구를 통하여 얻어진 NaA 제올라이트 분리막은 증류 및 PVA 계열 고분자 분리막보다 우수한 성능을 나타냄을 알 수 있었다.

• 멤브레인
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• 제15권1호
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• pp.44-51
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• 2005

유기증기에 대한 PDMS의 단점을 보완하기 위해 4,4'-diphenylmethane diisocyanate (MDI)와 1,4-butanediol(BD)를 이용하여 poly(dimethylsiloxane)를 기초로 한 polyurethane-polysiloxanes (PU/PDMS)를 합성하였다. 그리고 poly(tetrafluoroethylene) (PTFE)를 다공성 지지체로 이용하여 복합막을 제조하여 SEM 분석으로 코팅층의 존재와 두께를 확인하였다. 증기투과실험에서 투과온도와 feed의 농도가 증가할수록 flux는 점차 증가하였고, separation factor는 이와 반대로 점차 감소하는 'trade-off'현상을 보였다. 본 연구에서의 PU/PDMS는 soft segment의 함량보다는 비교적 hard segment의 함량이 높기 때문에 투과온도의 증가에 따른 영향이 크지 않았던 것으로 사료된다. PU/PDMS막은 VOCs와 상대적으로 높은 친화도를 가지고 있기 때문에 PU/PDMS 균질막과 비교하여 복합막의 형태에서도 향상된 flux와 높은 separation factor를 나타내었다.

• 공업화학
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• 제9권5호
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• pp.698-703
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• 1998

실리콘고무 (polydimethylsiloxane, PDMS)막에 의한 trichloroethylene (TCE)과 chlorobenzene (CB)수용액의 투과증발실험을 수행하고 농도분극이 분리특성에 미치는 영향을 연구하였다. 경계층저항은 직렬저항모델을 사용하여 설명하였으며, 수용액으로부터 미량의 유기염화물을 제거하는 투과증발에서는 농도분극현상이 투과거동에 중요한 영향을 미치고 있음을 확인할 수 있었다. 같은 막두께에서, 막에 대한 친화력이나 선택투과성이 더 큰 TCE가 CB수용액보다 경계층저항의 영향이 더 크게 나타났다. 막두께가 증가할수록 경계층저항의 영향은 감소하고 막저항이 지배적이 되며, 겉보기분리계수는 증가하여 막의 고유분리계수에 가까워졌다.

• 가정과삶의질연구
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• 제28권2호
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• pp.17-26
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• 2010

This study aimed to explore psychological separation from parents, family adaptability, and child's adjustment to college, in order to assess general standards and sex difference. It also investigated explaining variables on children's adjustment to college. The study subjects were 243 college students(male students; 123, female students; 120).The data collected from questionnaire were analyzed by descriptive statistics, t test, Pearson's correlation and hierarchical multiple regression. The main results were as follows: Firstly, psychological separation from parents of college students were lower than those of average score. But family adaptability and adjustment to college of students were higher than those of average score. Secondly, psychological separation from parents was negatively correlated to adjustment to college, but family adaptability was positively correlated to adjustment to college. Finally, variables that explain child's adjustment to college was cohavitation with parents and family adaptability. In addition to these variables, psychological separation from parents was a major factor for female students.

• 한국주거학회논문집
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• 제12권4호
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• pp.105-113
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• 2001

This research indicates to controversial point that store equipments were not applying correct development factor in the each apartment house by that change rate by scale and uniformity of form and inefficiency, effect of discount store is increasing in apartment house and progressed research. The result are as follows; First, interior main point of store of that influence greatly to change rate number of store be. Second, being lot area in jar in outside factor of store. Third, discount store separation appeared by leading person who influence greatly to change rate in middle who is contiguity market singleness residential quarter and contiguity existence of commercial district and nonexistence and discount store separation of only outside right near at hand. Construction of commerce equipment may have to consist in practical apartment house after examine various kinds factor such as store indoor, store outside and only outside while plan practical use of systematic and efficient commerce equipment focusing more in efficient utilization of commerce institution that consist after plan that is not planed commerce equipment focusing in development in plan of commerce equipment in apartment house hereafter accordingly.

• 약학회지
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• 제33권2호
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• pp.129-139
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• 1989

New diamide chiral stationary phases of four systematically substituted optically active N-(N-benzoyl-L-amino acid)-anilide synthesized from L-valine, L-leucine, L-isoleucine, and L-phenylalanine were described. The behaviors of these diamides as optically active stationary phases for the separation of N-trifluoroacetyl-D,L-amino acids were examined with respect to separation factors(${\alpha}$) and thermodynamic properties of interaction. The separation of twelve N-trifluoroacetyl-D,L-amino acid isopropyl esters were improved by the order of N-(N-benzoyl-L-leucyl)-anilide>N-(N-benzoyl-L-isoleucyl)-anilide>N-(N-benzoyl-L-valyl)-anilide>N-(N-benzoyl-L-phenylalanyl)-anilide. Eight amino acid derivatives with non-polar R-group and threonine, serine, aspartic acid, and glutamic acid enantiomers were separated on N-(N-benzoyl-L-leucyl)-anilide as chiral stationary phase with good separation factor between 1.07-1.25. The separation factors decreased with respect to increasing column temperature. Possible working temperature of diamide phase was between $130-190^{\circ}C$ for N-(N-benzoyl-L-phenylalanyl)-anilide and $130-180^{\circ}C$ for other three diamide phases. The differential Gibb's free energy (${\Delta}{\Delta}G$) of enantiomers was in the range of -100--180 cal/mol for ten amino acids and -40--60 cal/mol for alanine and aspartic acid.

• Structural Engineering and Mechanics
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• 제14권5호
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• pp.565-574
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• 2002

This paper presents a method for predicting premature separation of carbon fiber reinforced plastic (CFRP) plates from strengthened steel beams. The fracture criterion based on material-induced singularity is formulated in terms of a singular intensity factor. Static test on double strap joints was selected to provide the critical stress intensity factor in the criterion because good degree of accuracy and consistency of experimental data can be expected compared with the unsymmetrically loaded single lap joints. The debond/separation loads of steel beams with different CFRP lengths were measured and compared with those predicted from the criterion. Good agreement between the test results and the prediction was found.

• Journal of Oral Medicine and Pain
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• 제25권1호
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• pp.9-28
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• 2000

The purpose of this article, the first part of series, is to describe the general theory applicable to various chromatographic procedures. History of chromatography, separation of matters, classification of chromatography, underlying principles of separation in chromatography, covering resolution, column efficiency, column selectivity, and capacity factor, movement of solute in chromatographic phase, including elution development, displacement development, and frontal analysis, were discussed. Mathematical description of plate theory and thermodynamic viewpoint of retention were emphasized.

• 멤브레인
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• 제6권4호
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• pp.242-249
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• 1996

물/에탄올 수용액에 대한 투과증발특성을 개선하기 위하여 키토산을 이용하여 키토산/폴리비닐알콜 블렌드, 인산화 키토산 복합막을 제조하였다. 키토산과 폴리비닐알콜은 조성을 변화시키면서 블렌드를 얻을 수 있었으며, 글루탈알데히드를 이용하여 가교 방법과 조건을 변화시켜서 가교된 키토산/폴리비닐알콜 복합막을 제조하였다. 가교 농도와 가교 시간이 증가할수록 선택도는 증가하였으며 투과유량은 감소하였다. 글루탈알데히드를 가교제로서 키토산용액에 직접 첨가한 경우가 표면만을 가교한 경우보다 우수한 투과증발 성능을 나타내었다. 또한 인산화반응을 통하여 반응시간에 따라서 인산화도가 조절된 인산화 키토산을 얻었으며 이를 이용하여 인산화키토산 복합막을 제조하였다. 반응시간이 증가할수록 인함량이 증가하였으며 더불어 인산기의 도입에 따른 친수성의 증가로 선택도의 증가가 나타났다.

• Korean Membrane Journal
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• 제1권1호
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• pp.65-72
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• 1999

The surface of polypropylene membrane was modified by plasma treatment using Ar,$N_{2}$, $NH_{2}$ and $O_{2}$ Permeabilities for $CO_{2}$, $N_{2}$ and separation factor for $CO_{2}$ relative to $N_{2}$ were measured. The permeation experiments were performed by a variable volume method at $25^{\circ}C$ and 0.303MPa. The effects of the plasma conditions such as treatement time power input gas flow rate and pressure in the reactor on the transport properties of modified membrane were investigated. The surface of the plasma treated membrane was analyzed by means of FTIR-ATR XPS and AFM. The surface structure of the plasma treated membrane was fairly different from that of the untreated membrane. Although the permeation rates for both $CO_{2}$ and $N_{2}$ decreased with increasing plasma treatement time the separation factor was found to be improved by the plasma treatement. The operating conditions of plasma treatement imposed on membranes had notable effect on the permeability and separation factor.