• Korean Chemical Engineering Research
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• 제48권4호
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• pp.434-439
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• 2010

Isophorone diisocyanate(IPDI), poly(tetramethyleneglycol)(PTMG), dimethylol propionic acid(DMPA)를 출발물질로 하여 NCO terminated prepolymer가 합성되었다. 이 prepolymer의 NCO기를 silane으로 capping하기 위해 0~0.02 mole로 첨가량이 조절된 aminopropyl triethoxysilane(APS)이 첨가되었다. 제조된 용액의 평균 입경은 APS의 첨가량이 증가함에 따라 증가하였다. 또한 제조된 코팅 필름의 연필 경도 및 열적안정성은 순수한 수분산 폴리우레탄보다 우수하였다.

• 컴퓨터교육학회논문지
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• 제10권2호
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• pp.89-100
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• 2007

대규모 집단을 대상으로 시행하는 서답형 문항을 수기 채점 방식으로 채점하는 경우 채점 과정에서 발생하는 채점 오차를 줄이기 위해서는 많은 노력과 시간을 필요로 한다. 이러한 문제점을 해결하기 위해 세계 각국에서는 서답형 문항 채점 시스템을 개발하여 운용하고 있지만, 국내에서는 채점 시스템의 기초적인 연구도 미흡한 실정이다. 본 연구의 목적은 '서답형 문항의 인터넷 기반 채점 시스템' 설계의 기반을 마련하는데 있다. 시스템 설계의 기반 마련을 위한 시스템의 개요와 기본 설계도, 채점자 배정 방법, 채점자 신뢰도 추정에 의한 채점자 오류 검색 알고리즘을 제안하였다. 본 시스템은 실시간으로 채점 신뢰도를 추정하여 채점 오차를 보정할 수 있는 장점이 있다.

• 한국과학교육학회지
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• 제13권2호
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• pp.219-229
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• 1993

The purpose of this study is to investigate college science students' and science teachers' understanding of chromosomal behavior in the context of cell division. The research problems were as follows: 1. What is the level of college science students' understandings of chromosomal behaviors? 2. What is the level of science teachers' understandings of chromosomal behaviors? 3. What is the level of understanding by grade and major area? The sample consisted of 28 sophomore, 17 junior and 23 senior biology students; and 23 middle school science teachers and 14 high school biology teachers. The instrument of the study was a short answer required paper and pencil test. The results of the study were as follows: 1) About 15 percent of the sample could not count the number of chromosome in a cell in appropriate. 2) Seventy percent of the students, and 80 percent of the teachers identified homologous chromosomes as ones with the similar shape and size, and 30 percent of the whole sample could not pair two homologous chromosomes. 3) About 70 percent of the students and 30 percent of the teachers could not mark corresponding allele on chromosome. 4) Biology major students showed higher understanding of overall chromosomal behaviors than non Biology students. Based upon the results, some implications were made. The major one was a development of a teaching model in which students can improve the ability to connect chromosome theory to mendelian genetics.

• 대한전자공학회논문지TC
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• 제39권7호
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• pp.38-45
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• 2002

본 논문은 손실 매질 내에 매설된 선 전류 안테나에 의한 크기가 큰 완전도체 표적의 산란파를 해석하기 위한 전장적분식을 도출하였다. Sommerfeld 형태의 적분은 어떤 해석영역에 대하여 계산의 어려움과 제약들을 가지고 있으며, 많은 계산시간이 필요하다. 반면 최대 경사적분은 빠른 결과의 산출을 제공하였으며, 또한 그 계산 결과는 모든 해석 영역에 적용 가능하다. 임의의 완전도체 표적의 산란파는 최대경사적분법과 MOM 방법이 사용되었으며, 계산 결과는 가우시안 구적법과 GPOF 방법에 의해 비교되었다.

• 한국수학교육학회지시리즈A:수학교육
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• 제52권3호
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• pp.271-301
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• 2013

The purpose of the study was to investigate how students generalize and prove the factoring of $x^n-1$ using a Computer Algebra System application and the role of CAS in this process. The theoretical framework consists of the anthropological and the instrumental approach. In particular, the basis of the Task-Technique-Theorization(T-T-T) frame adapted form Chevallard's anthropological approach of Didactics is utilized. We found that Technique-Theorization emerges in mutual interaction between paper-and-pencil techniques and computer algebra techniques. And this interaction led to the students' theoretical reflection and conceptual understanding. In this process, we could identify three epistemic role of CAS : the role of checking the result, the role of cognitive stimulation and the role of extending thinking. Therefore CAS plays on a epistemic role of checking the result of a task, stimulating the student' cognition and extending their thinking as well as pragmatic role of producing the result of a input.

• 대한기계학회논문집A
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• 제24권12호
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• pp.2891-2898
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• 2000

The objective of this paper is to develop a fiber-optic acoustic emission(AE) sensor applicable to on-line monitoring systems which is suitable for long-distance signal transmission. An AE sensor was developed by use of a fiber-optic cantilever and an extrinsic Fabry-Perot interferometer(EEPI). The efficiency of signal processing was improved by driving the high frequency AE signals into the low frequency ones. In order to verify the developed sensor, the tensile and the pencil lead fracture(PLF) tests were performed including the experiment showing the Kaiser effect. Form tests, AE signals were successfully detected in the elastic-plastic deformation range, especially higher signals at the crack propagation. The developed sensor was expected to be used for an on-line monitoring of crack propagation in mechanical system.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.180-182
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• 2002

A Proton Therapy Center was established this year in National Cancer Center, Korea. We chose IBA of Belgium as the vendor of the equipment package. A 230 MeV fixed-energy cyclotron will deliver proton beams into two gantry rooms, one horizontal beam room, and one experimental station. The building for the equipment is currently under design with a special emphasis on radiation shielding. Installation of equipments is expected to begin in September next year starting with the first gantry, and the acceptance test will be performed about a year later. To generate therapeutic radiation fields the wobbling method will be a main treatment mode for the first gantry. A pencil beam scanning system on the other hand will be equipped for the second gantry relying on the availability at the time of installation. The beam scanning with intensity modulation adapted will be a most advanced form in radiation therapy known as IMPT. Some details on the project progress, scope of the system, and design of building are described.

• 한국레이저가공학회지
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• 제3권2호
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• pp.35-43
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• 2000

Laser direct patterning of the coated photoresit (PMER-NSG31B) layer was studied to make halftone dots on gravure printing roll. The selective laser hardening of photoresist by Ar-ion laser(wavelength : 333.6nm∼363.8nm) was controlled by the A/O modulator. The coating thickness in the range of 5㎛∼11㎛ could be obtained by using the up-down directional moving device along the vertically located roll. The width, thickness and hardness of the hardened lines formed under laser power of 200∼260㎽ and irradiation time of 4.4∼6.6$\mu$ sec/point were investigated after developing. The hardened width increased according to the increase of coating thickness. Though the hardened thickness was changed due to the effect of the developing solution, the hardened layer showed good resistance to the scratching of 2H pencil. Also, the hardened minimum line widths of 10㎛ could be obtained. The change of line width was also found after etching, and the minimum line widths of 6㎛ could be obtained. The hardened lines showed the good resistance to the etching solution. Finally, the experimental data could be applied to make gravure halftone dots using the developed imaging process, successfully.

• 건축역사연구
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• 제21권6호
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• pp.35-44
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• 2012

This paper aimed at investigating into the origin and meaning of the Japanese architect Terunobu Fujimori's 'piercing column', and drew a conclusion as follows. First, the piercing column that made its first appearance in his architect debut work Jinchokan Moriya Historical Museum (1991) was conceived unexpectedly from pencil lines on a sketch that went through over the building's roof. And the tree-like natural treatment of the column's surface was influenced by Takamasa Yoshizaka's description of a Mongolian mud-house. Second, most of piercing columns in his later works have nothing to do with a structural role as in Jinchokan, but were designed for a visual effect and as a symbolic gesture. Again, they allude to a tree in nature through a roughly peeling treatment of the surface. Third, considering his ideas in History of Humankind and Architecture (2005), his column could be related to a universal origin of architecture and a symbol of the sun-god faith, and in particular to independent columns of Japanese Shito shrines, such as 'Onbashira' in Suwa and 'Iwanebashira' in Izumo. That is to say, the Fujimori column is a medium that implies the animistic nature-faith of Japan. Nevertheless, Fujimori's naturalism hints at a disquieting quality through an intentional artificiality and a provocative conflict between structure and finish of a building, which might be one aspect of the modern condition, 'uncanny'.

• 대한인간공학회지
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• 제31권3호
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• pp.463-467
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• 2012

This study aims to empirically investigate population stereotype of burner-control linkage of four-stove gas range for Koreans. Background: The previous studies' results for gas range stereotypes were different depending upon methods adopted, i.e., whether using questionnaires, computer simulation or physical models. It is known that the physical model experiment should not be methodologically replaced by the computer simulation or paper-and-pencil tests. Stereotype of gas range for Koreans was surveyed based on questionnaires, but has not been dealt with by using physical models. Method: An experiment was conducted to investigate stereotype of four-burner gas range, in which 32 subjects participated and a real gas range available in the market was bought and used. Four types of burner-control linkage were used as independent variable, and reaction time as dependent variable. Results: ANOVA revealed that four types of burner-control linkage and subjects' gender were not significant on reaction time. Duncan's multiple range test showed that reaction times for type III was significantly lower than those for the other three types of burner-control linkage(${\alpha}$=0.05). Conclusion: It is concluded based on the results of this study that stereotype of gas range for Koreans is type III. This is in agreement with results of existing studies using questionnaire survey, while different from those based on physical models. Application: The results of this study would be useful as an ergonomic guideline when designing gas ranges or similar equipments for minimizing operation errors.