• Proceedings of the Membrane Society of Korea Conference
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• 1997.06a
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• pp.159-174
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• 1997

삼투현상이란 반투막을 사이에 두소 저농도의 용매가 고농도의 용액으로 이동하는 현상으로 막양측 용매의 화학포텐셜이 같아지게 되면 용매의 이동은 정지되고 수두차 만큼의 삼투압차가 발생한다. 이 때 고농도 용액측에 삼투압차 이상의 압력을 가하게 되면 삼투현상과는 반대로 고농도 용액측의 용매가 저농도의 용액측으로 역류하는데 이를 역삼투현상이라 한다. 역삼투현상을 이용하여 물질을 분리하는 역삼투 공정은 막의 물리화학적 특성, 분리대상물질의 물리화학적 특성, 그리고 압력차를 추진력으로 하는 세가지 요소의 조합에 의해 행하여 진다. 역삼투는 분자크기에 따른 분리조작이 아니므로 정밀여과나 한외여과에서와 같은 유기물질의 침착현상이 적으며 결과적으로 막의 수명도 길어진다. 역삼투막은 용존염을 분리제거할 뿐만 아니라 분자량이 적은 유기물 및 Aromatic hydrocarbon 등의 분리조작에도 그 이용가능성이 고조되고 있다.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.696-703
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• 2005

The definition of cake is not established for cake filtration, and especially the definition was impossible for the filtration of the floc already sedimented. The definition is proposed with the experimental method named 'filtration-permeation'. The limit of water content which can be achieved with cake filtration of floc was established with the definition of cake. The expression operation of which the purpose is to reduce the water content of pre-formed filter cake is calculated with our 'unified theory on solid-liquid separation' and compared with the experimental results. The importance of expression is analyzed by the calculated whole procedure of cake filtration and expression. The method determining the most effective operational conditions of filter press including the cake discharge and washing time is proposed.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.578-588
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• 1999

The purpose of this study is to develope the more effective chemistry teaching strategy through analyzing the demanded cognitive levels of contents in high school chemistry I textbooks and the cognitive levels of students who learn these textbooks. For this purpose, the levets of cognitive development stages of 821 second grade students of high schools in Seoul City were anaIyzed using the GALT short version test. The demanded cognitive levels of understanding the contents of chemistry I textbooks in high school were analyzed using the curriculum analysis taxonomy developed by CSMS (Concept in Secondaly Mathematics and Science) program of the Great Britain. The resuIts showed that the proportion of students in the concrete operational stage, the transition stage, and the formal operational stage was l0.7%, 43.0% and 46.3%, respectively. The demanded levels of textbook contents were mostly the early formal operational stages. The concepts demanded the level of the late formal operational stage were 'atomic and molecular weight', 'stoichiometry of chemical reaction', and 'periodic properties of elements'. The results will be helpful for teachers in knowing what concepts are difficult for students to understand and in planning strategies for teaching those concepts. To demonstrate the application of the results obtained in this study, an example of developing teaching strategy which includes the adjustment of cognitive level of contents was shown.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.274-276
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• 2005

본 논문에서는 단백질 상호작용 네트워크의 복잡성을 제어하고 생물학자가 자신이 설정한 조건을 만족시키는 환경에서 추가적인 다양한 제약 조건을 가하면서 원하는 상호작용 네트워크를 구성하고 조작할 수 있도록 지원하는 Constraints Based Dynamic Protein Interaction Network 이라는 새로운 개념의 단백질 상호작용 네트워크를 소개한다. 본 기법에서는 기존의 단백질 상호작용 네트워크에서 주로 사용하는 단백질 상호작용 정보뿐 아니라 단백질 상호작용에 영향을 미칠 수 있는 개개 단백질의 물리 화학적 특성 및 위치 정보와 상호작용의 환경 정보도 단백질 상호작용 네트워크 구성에 활용한다. 제안된 네트워크상에서 생물학자는 단백질 상호작용 네트워크 구성 조건을 변경하거나 얻어진 네트워크에 변경을 가하면서 점차 자신이 원하는 의미 일은 대사경로 모델을 찾거나, 제약조건의 다양한 조작을 통하여 생물학적 실험을 통하여 얻어진 대사모델의 유효성을 검증하는 것도 가능하다.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.739-750
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• 2012

The purpose of this study is to analyze the cognitive demands level of the description about 'pure substance and mixture compound', 'ionic compound', 'molecule' on the 'science2' textbooks by the 2007 revised curriculum. The three types of Curriculum Analysis Taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science2' textbooks. The first, the cognitive demand level about 'pure substance and mixture compound' on many textbooks is a late concrete operational stage because of class inclusion and hierarchical classification. And the descriptions as 'pure substance is conserved even when mixed with other pure substance' is a early formal operational stage. The second, the cognitive demand level about 'ionic compound' and 'molecule' is a early formal operational stage, because of "Formal modeling is the indirect interpretation of reality by deductive comparison from a postulated system with its own rules" and "Atoms have a structure". The third, the terms as 'ionic bonding', 'ionic compound', 'chemical formula', 'covalent bonding', 'covalent compound', and 'molecular formula' have been used on many 'science2' textbooks. Those terms would be used later on 'chemistry I' and 'chemistry II' in senior high school but not even 'science3' and 'science'.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.73-74
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• 1996

역삼투막은 높은 투과율과 배제율, 기계적 강도, 열적 안정성, 화학적 안정성, 성형성, 경제성 등의 여러 가지 조건을 동시에 만족시켜야 한다. 복합막을 통한 역삼투막의 제조는 위의 조건들을 만족시키는 역삼투막을 제조할 수 있는 훌륭한 제조 방법인데 지지막과 표면의 활성층을 여러 가지로 조합하여 다양한 성능의 막을 개발할 수 있기 때문이다. 지지막은 다공질의 고분자막으로 기계적 강도, 화학적.열적 안정성 등이 있어야 하는데 역삼투막이 가혹한 운전 조건에서 조작되기 때문이다. 그리고 지지막은 활성층과 안정된 결합을 할 수 있는 물리적 및 화학적 성질을 지녀야 한다. 활성층은 분리가 일어나는 곳으로 막의 배제율과 투과특성에 큰 영향을 미친다. 따라서 복합막의 제조에 있어서 고려되어야 할 사항은 지지막과 활성층의 재질의 선택, 지지막의 특성, 지지막 위에 얇고 안정된 활성층의 도포 방법, 성능향상과 활성층의 안정화를 위한 제조된 복합막의 후처리 방법 등이다. 지지막 위에 활성층을 도포시키는 방법은 계면중합법, 박층분산법, 침지코팅법, 기상증착법 등을 들 수 있는데 이 중에서 계면중합법을 이용한 복합막의 제조가 가장 실용적인 방법으로 인정되고 있고 현재 실용화되어 있다.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.799-804
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• 2018

The separation and purification of 2,6-dimethylnaphthalene (2,6-DMN) present in the light cycle oil (LCO) fraction was investigated by a crystallization operation. Solute crystallization (SC) was performed using LCO fraction and iso-propyl alcohol as a raw material and a SC solvent, respectively. Increasing the operation temperature and volume ratio of the solvent to the raw material (S/F) resulted in improving the purity of 2,6-DMN, whereas the yield decreased. As a result of the crystallization operation in three steps containing the SC using LCO fraction (13.9% 2,6-DMN) and isopropyl alcohol, the re-crystallization 1 (RC 1) using the crystals recovered by SC and methyl acetate, and RC 2 using the crystals recovered by RC 1 and methyl acetate, the crystal with 99.9% 2,6-DMN was recovered with 19.5% yield. Furthermore, the separation and purification process of 2,6-DMN present in the LCO fraction was reevaluated by using the experimental results obtained through each operations of SC, RC 1, and RC 2.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.11a
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• pp.43-47
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• 1994

화학 열펌프 시스템의 반응기 설계를 위하여 정적 설계의 결과를 이용하여 시간에 따른 전화율, 온도, 압력, 출력 등의 변화에 대한 모사를 시도하였다. 정적 모사를 통한 설계결과는 동적 거동 모사의 결과와 유사하였으며, 이로부터 정적모사가 동적모사를 위한 적절한 초기치와 기초 설계 정보를 제공함을 알 수 있었다. 본 연구를 통하여 확립된 설계절차와 해석방법에 따른 사례연구를 통하여 향후 실용화될 화학 열펌프 시스템의 개략적인 사양과 바람직한 설계방향을 제시 할 수 있었으며, 반응기의 조작에 따른 제어변수의 영향을 평가하는 기준을 마련할 수 있었다.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.645-653
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• 2004

The purpose of this study was to compare and analyze the cognitive levels of 11th grade students and those required in high school chemistry I textbooks standardized by the 7th national education curriculum. For this study, the cognitive development stages of 456 11th grade students were surveyed using short-version GALT (group assessment of logical thinking). Furthermore, 15 basic concepts were extracted from the contents on water and air, 2 units in chemistry I order to analyze the cognitive levels necessary for understanding high school textbooks, using CAT (curriculum analysis taxonomy). The results showed that 52.5% of the surveyed 11th grade students reached the formal operational level, 28.3% transitional levels, and 19.5% concrete operational levels. 68.9% of the academic high school students and 6.6% of the technical high school students reached the formal operational levels, and the ratio of formation was very different in each logics. As a result of the analyzing the cognitive levels needed for understanding chemistry I textbook contents, in spite of a change in national education curriculum, there were no great change in cognitive levels required by scientific concept except some inquiry activities. The cognitive levels in high school chemistry I textbooks by the 7th national education curriculum appeared higher than the cognitive levels of 11th grade student, but cognitive levels of inquiry activities were similar to the cognitive levels of the students. Chemistry teachers thought of chemistry I textbooks by the 7th national education curriculum as desirable because scientific concepts were reduced and a lot of real life materials were adapted. However, they pointed out a problem of difference in contents levels compared with chemistry I textbooks because scientific concepts were greatly reduced in chemistry I textbooks. The cognitive levels required in chemistry I textbooks still appeared higher than those of the students. Consequently, various teaching and learning methods and materials will have to be developed to be suitable for the students' cognitive levels.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.640-655
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• 2013

The purpose of this study is to analyze the cognitive demands level of the description about 'changes of state' and 'kinetic theory' on the 'science 1' textbooks by the 2007 revised curriculum. The three types of curriculum analysis taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science 1' textbooks. The most higher level of cognitive demands about the concepts have been discussed here due to the focus of the concepts. The first, the cognitive demand level about 'three states of substances' depending on the motion of their particles in 6 textbooks is a early formal operational stage because of using by the application of kinetic theory. The second, the cognitive demand level about 'diffusion' and 'evaporation' is a early formal operational stage, because the particles move around faster so they can change their position. The third, the cognitive level of the pressure and volume in a gas is a early formal operational stage because of explaining only phenomena in simple correspondence with formal model of kinetic theory. And simple functional relationships beyond linear on the graph of the volume and pressure of gas, the volume and temperature of gas is also a early formal operational stage. The fourth, the cognitive level of the energy of heat by a change of the state is also a early formal operational stage because kinetic theory picture accepted as providing explanation by the change of the state. And functional relationships beyond linear on the graph of the explanation of boiling point of water in water is also a early formal operational stage.