히드록시 프로필 키틴과 키토산의 합성 및 이들의 액정성에 관한 연구

마영대,정승용,정종현,김경희 단국대학교 1998 論文集 Vol.33 No.-

The hydroxypropylated chitin and chitosan were prepared by reaction of alkali chitin and chitosan with propylene oxide (1,2­epoxypropane) in hexane as a second dilute solvent at 70℃. The derivatives with different total degree of substitution (DS) and molar substitution (MS) were obtained by adjusting the mole ratio of propylene oxide and NaOH to glucosamine unit or N­acetyl­glucosamine unit and the reaction pressure. The MS value and the site of substitution were determined by the FTIR and ^1H­NMR analysis. The results showed that all the samples are the O­alkylation products, suggesting that the DS values of all the derivatives are less than 2. On the other hand, the observed values of MS for almost all the samples were found to be larger than 2, indicating that propylene oxide molecules became more and more difficult to reach the main cain as the side chain grew. By optical microscopic observation, the derivatives with high MS values, all the which are soluble in water as well as common organic solvents, were found to form both thermotropic and lyotropic phases.

Nylon 66 織物 撥水加工에 관한 硏究

南憬鉉,姜大榮,智東宣 단국대학교 대학원 1984 學術論叢 Vol.8 No.-

Polymethyl­H­siloxane (PMHS) was synthesized by mole ratio 1 : 2 of methylhydrogendichlorosilane to trimethylchlorosilane reacted H_2O with dioxance for catalyser in room temperature. Polydimethylsiloxan (PDMS) was synthesized by hydrolysised of dimethyldichlorosilane with H_2O. Low D.P of epoxy compounds was synthesized by mole ratio 0.13 : 0.48 of bisphenol­S to epichlorohydrin for 120 min. in 90±5℃. Also the resin finishing agent, Dimethylol urea was synthesized by mole ratio 1.8 : 1 of formaldehyde to urea for 45 min. in 80℃. The structures of these compounds were determined by infra red absorption spectra. These agents were emulsified independent of conjunctive one another, with noionic surfactant. According to treating the prepared emulsions to nlyon 66, the following results were obtained. 1. The emulsion prepared with the recipes of composition ratio PMHS : PDMS : Epoxy=24 : 6 : 1, comparing with other emulsions, is proved as excellent in water repellency and in durability to repeated washings or dry cleannings. 2. The conclusion when treated with the solution of dimethylol urea synthesized resin finishing agent which was added by treat solution is reacheclthai the water repellency and the wrinkle recorevy shoued notransformation at all. 3. The optimum concentration of the treating solution diluted by using above emulsion is about 1%.

CAN(Controller Area Network)을 이용한 조립셀(Assembly Cell)구현 및 시뮬레이션에 관한 연구

김진경,김대원 명지대학교 대학원 1999 대학원논문집 Vol.3 No.-

This paper analyzes the performance of network using CAN protocol according to the variation of factors, such as a number of nodes, transmission speed, transmitted data size and so on. The CAN protocol is generally known to be good characteristics of real-time, but it is not possible to guarantee the timing performance of lower priority messages. We show the difference of time-delay between simulations and practical experiments about real-time performance of lower priority messages. Also, we make a mathematical model of the CAN protocol and propose the concept of a message control loop. The proper number of nodes, transmission speed, and transmitted data size are obtained to build the most efficient network through simulation.

열처리 상태가 10Cr-1Mo-VNbN 주강의 기계적 성질 및 용접성에 미치는 영향

손대영,방국수,이경운,지병하 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.11

Mechanical properties and weldability such as HAZ hardness, cold cracking susceptibility and hot ductility of two differently heat treated 10Cr-1Mo-VNbN cast steels were measured and compared. Because of high hardenability of the cast steel, as-annealed cast steel showed martensitic microstructure and thus had higher hardness than annealed-normalized-tempered cast steel which had tempered martensite. Because the welding electrode used resulted in a high hardness weld metal, both cast steels showed same weld metal cold cracking susceptibility even though the as-annealed cast steel had higher HAZ hardness than the annealed-normalizedtempered cast steel. Both cast steels had excellent hot ductility in high temperature range, indicating no risk of grain boundary liquation cracking in the HAZ. However, the as-annealed cast steel showed an inferior ductility in the intermediate temperature range of 1000~1150℃ because of larger unrecrystallized grain size.

선천성 기형을 동반한 단일 제대동맥 신생아 2례

정대봉,박동호,김명철,문경래,박영봉,박상기 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.1

A single umbilical artery is present in about 2/1,000 births. Approximately 10-15% of Infants with a single umbilical artery have congenital abnormalities, usually more than one, chromosomal abnormalities, fetal growth retradation, prematurity, perinatal mortality and many such infants are stillborn or die shortly after birth. We experienced two cases of single umbilical artery. One had congenital malformation of left ectopic fused kidney, but hadn't cytogenetic abnomality. The other had cytogenetic abnormality of 46XY,inv(6)(q11q16), morphologic abnormalities of polydactyly & lower palpebral fissure and congenital abnormalities of tracheoesophageal atresia & TOF. We reported these cases with a related literature review.

RAPD(Random Amplified Polymorphic DNA)법을 이용한 한약재의 판별 연구

김대원,김도균,안선경,조동욱 한국한의학연구원 1997 한국한의학연구원논문집 Vol.3 No.1

Conventionally, identification and classification methods of natural products include the morphological survey and assay of chemical disposition. Using these methods, however, is not satisfying for the precise identification of natural products because they are often variable in the compositions, genomic DNA analysis such as RAPD, RFLP and Amp-FLP can be adopted for this purpose. In this study, various ginsengs and bear gall bladder were tested for the development of genetic identification and classification method. Varieties of ginsengs such as, P. ginseng, P. quinquefolium, P. japonicus and P. notohinseng, were genetically analyzed by RAPD. Also, DNA isolated form Bear blood and gall bladder, Ursus thibetanus, Ursus americanus and Ursus arctors, were analyzed by the same method. The results demonstrated that the identification and classification of bear gall bladder and various ginsengs were possible by RAPD analysis. Therefore, this method was thought to be used as a additional method for the identification of other natural products.

초·중등 및 대학교재 중 물질특성에 대한 연계성 연구

李京玧,文正大,文星培 釜山大學校 師範大學 1998 교사교육연구 Vol.36 No.-

Material Characteristics contents in the chemistry textbooks from elementary school to college were investigated to consider the effectiveness of curricular articulation. For this purpose, the eleven subjects of chemistry contents were selected from chemistry textbooks, and the learning purpose and contents were analyzed through the classification rules. The results of analysis showed that total articulation were relatively effective. But the gaps partly appeared in case of comparing with the level of intellectural development of student. On the based of this results a new concept diagrams were proposed through the structure diagrams considered both macro and micro aspect. To develop the curricular articulation between the school units it is important that textbooks should be with the consistent plan after the discussion with the actual teachers of the school units.

이온주입이 금속의 일함수에 미치는 영향(Ⅰ)

김현경,강석태,황정남,이철주,최대선,정병두 연세대학교 자연과학연구소 1984 學術論文集 Vol.13 No.-

이온 주입이 일함수 차이에 미치는 영향을 연구하기 위하여 낮은 에너지 이온 가속기, 전자총과 기타 일함수 차이를 측정하기 위한 장치를 설계, 제작하였다. 제작된 이온 가속기의 집속 특성은 이론적인 값과 일치하였다. 즉, 집속 렌즈의 확대율이 이론값은 2.0인데 비하여 1.2로 상당히 작은 값이었다. 또한 집속 렌즈의 전압 V_L과 추출 전압 V_e에 의한 집속 특성 역시 이론값과 매우 잘 일치하였다 . 제작된 장치를 사용하여 다결정 Cu와 Ni의 일함수 차이를 측정한 결과 0.45eV임을 알았다. 그리고 전자선을 이용하여 억제 전위차로 일함수를 측정할때 입사 전자의 반사율을 고려해야 함을 알았다. Low energy ion accelerator, electron gun, and apparatus for measuring work function difference are designed and constructed in order to study the effect of ion implantation on the work function. The focusing properties of accelerator is coincided with theoretical results; the magnification of Einzel lens is found to be 1.2, while theoretical value is 2.0, and the focal properties as a function of V_L/V_e are in good agreement with theory. Using these systems, the work function difference between polycrystalline Cu and Ni is found to be 0.45eV, and the experimental retarding potential plots indicate close agreement with the theoretical values modified by electron reflection.

화학 변화 개념에 대한 중학교 2학년 학생들의 선개념 조사 및 선개념 갈등상황 제시를 통한 개념변화 학습이론의 효과 분석

白盛惠,강대훈,金惠敬,蔡禹基,權鈞 한국교원대학교 과학교육연구소 1999 청람과학교육연구논총 Vol.9 No.1

본 연구에서는 중학교 2학년 학생들의 선개념을 조사하고, 개념변화 학습이론을 적용한 과학 수업을 제공함으로써 학습자의 학습 동기가 잘못된 선개념을 올바른 과학 개념으로 바꾸는데 어떠한 역할을 하는지 알아보았다. 이를 위하여 개념변화 학습이론에 근거한 수업을 받은 학습자의 선개념의 변화를 전통적인 수업을 받은 학습자의 선개념 변화와 비교하여 보았다. 연구 결과, 학생들은 중학교 1학년때 배운 물리 변화를 화학 변화의 개념과 혼동하여 화학 변화를 단순히 물리적 변화인 상태 변화로 인식하거나, 이와 관련된 잘못된 선개념들을 많이 가지고 있는 것으로 나타났다. 또한 화학 변화의 한 예인 연소 현상에 대해서는 초등학교 6학년부터 학습한 내용임에도 불구하고 눈에 보이지 않는 산소의 결합을 인식하지 못하였으며, 많은 문제의 상황에서 질량 보존의 법칙을 기계적으로 적용하는 특징도 보였다. 수업의 효과로는 개념변화 수업을 받은 학생들이 과학적 개념을 부분적으로 또는 완벽하게 이해를 한 비율은 50%를 넘지 못하였다. 그러나 이 비율은 교과서에 의존한 전통적인 수업을 받은 학생들의 과학적 개념 이해 비율인 39% 보다는 높은 비율이라고 할 수 있다. 개념변화 수업을 받은 학생들의 올바른 과학 개념 습득 비율이 전통적 수업을 받은 학생들의 비율보다 통계적으로 유의미하게 높은 것으로 나타났다. 따라서 본 연구에서 개발하여 실시한 개념변화 수업은 학습자의 올바른 과학 개념 습득에 효과적이라고 할 수 있다. Preconceptions of middle school students related to chemical change the students are surveyed. The students are divided into experimental group that are learned by concept change theory teaching model, and control group that are learned by traditional teaching method based on science textbooks. After the planned classes, the tendencies of concept change of the two groups according to students learning motivations are analyzed. New teaching methods, which based on concept change learning model and students learning motivations, developed by this research. And the effects of the new teaching method are testified. As a result, it is proved that most of the students have a lot of preconceptions, and persist the wrong conceptions after the classes. This tendency is same in the control group and in the experimental group.

돼지 비장으로부터 분비성 포스포리파아제 A₂의 효소 활성을 저해하는 인자의 동정

신혜숙,김대경 중앙대학교 약학연구소 1996 약학 논총 Vol.10 No.-

It has been known that secretory group Ⅱ phospholipase A_2 (PLA_2) plays a role in a variety of cell responses including inflammation and platelet aggregation through the production of bioactive lipid mediators such as eicosanoids and platelet activating factor. Although it has been suggested that there may be a regulatory endogenous factor which inhibits the secretory PLA_2 activity, its entity and biochemical properties has not been elucidated yet. In the present study we detected an inhibitory protein for the secretory group Ⅱ PLA_2 in 100,000 x g supernatants obtained from the homogenates of rat platelets and porcine spleen. The inhibitory protein was bound to an anionic exchange DEAE-5PW HPLC column and did not inhibit poricine pancreatic group Ⅰ and porcine spleen 100 kDa cytosolic PLA_2 activities. suggesting that it may selectively inhibit the secretory group Ⅱ PLA_2 activity.