열방성 액정중합체와 PEN과의 블렌드에 관한 연구

전옥철,최재곤 조선대학교 생산기술연구소 1998 生産技術硏究 Vol.20 No.1

A new semirigid liquid crystalline polyester(LCP) was synthesized by polycondensation of 2,6-naphthalenedicarbonyl dichloride with the corresponding diol having a hexamethylene group. Blends composed of poly(ethylene 2,6-naphthalate, PEN) were prepared by the coprecipitation from a common solvent. The thermal. mechanical properties and morphology of blends were examined using differential scanning calorimeter(DSC), scanning electron microscope(SEM), and dynamic mechanical thermal analyzer(DMTA). The glass transition ternperature(T_(g)) and the cold crystallization ternperature(T_(c)) of the PEN in the blends decreased with increasing the content of LCP and the LCP acted as a nucleating agent for the matrix polymers. The LCP phases in the blends were found to be finely and uniformly dispersed by SEM micrographs. The modulus of LCP/PEN blends were enhanced on the LCP content increase.

곁사슬을 갖는 새로운 액정중합체의 합성 및 특성

전옥철,김윤준,류범영,최재곤,조병욱,홍진후 조선대학교 생산기술연구소 1999 生産技術硏究 Vol.21 No.1

A series of wholly aromatic polyesters with side chains were synthesized by solution polycondensation from 2,5-dialkoxyterephthaloyl chlorides with the corresponding diol. The polymers showed the schlieren textures which is indicative of a nematic phase above their melting temperature. The inherent viscosities (η_(inh)) measured at 35℃ in phenol/p-chlorophenol/1,1,2,2-tetrachloroethane were 0.56-0.98 dℓ/g. The glass transition temperature (T_(g)) and melting temperature (T_(m)) decreased with increasing the length of the alkoxy side chain. Initial decomposition temperatures in TGA occurred at 338 ~ 363℃ in N₂ gas and thermal stability of polymers decreased with increasing the length of the side chain.

내열성 액정 고분자의 합성 및 복합재료

조병욱,전옥철,김윤준,한철,최재곤 조선대학교 생산기술연구소 1999 生産技術硏究 Vol.21 No.2

A new thermotropic liquid crystalline copolyester(TLCP) was synthesized by condensation polymerization of 2,6-naphthalene dicarbonyl chloride with the corresponding diol having a tetramethylene and a hexarnethylene group. The blends of the TLCP with PEN were prepared by the coprecipitation from a common solvent. The TLCP and blends (2, 5, 10 and 20wt% TLCP) were characterized in terms of their thermal, mechanical properties and morphology. The TLCP in the melt state showed nematic mesophase identified by thread-like optical texture. The glass transition temperature (T_(g)) and cold crystallization temperature (T_(c)) of PEN in the blends decreased with increasing the content of TLCP and the TLCP acted as anucleating agent for the matrix polymer. Interfacial adhesion between the TLCP and PEN seemed to be poor. The modulus of TLCP/PEN blends was enhanced as the TLCP content increased.

Fe_0.25Cu_0.25Co_0.5Cr_2S_4의 결정학적 및 자기적 성질

옥항남,백경선,서정철,김윤곤 圓光大學校 基礎自然科學硏究所 1988 基礎科學硏究誌 Vol.7 No.3

Co_0.5Fe_0.25Cu_0.25Cr_2S_4의 결정학적 및 자기적 성질을 뫼스바우어 분광법과 X선 회절법에 의하여 연구하였다. 결정구조는 입방스피넬이고 격자 상수는 a_0=9.909 Å이었다. 또한 전기사중국자 이동의 측정으로 부터 철이온이 사면체 자리에 위치하고 있음을 알았고 이성질체 이동 및 초미세자기장의 측정으로 부터 철이온의 전하가 +^3가임을 알 수 있었다. 초미세자기장의 온도의존성은 준강자성의 존재로써만 설명이 가능했으며 분자장 이론으로 분석해 본 결과, 6가지 초교환 상호작용중에서 두가지 AB 상호작용이 가장크고 또 음성이었다. 네엘온도는 281 K로 측정되었다. The crystallographic and magnetic properties of Fe _0.25Cu_0.25Co_0.5Cr_2S_4 have been studied by Mossbauer and x-ray measurements. The crystal stucture is the cubic spinel and the lattice parameter a_0 is found to be 9.909Å. It is also found from the quadrupole shift that iron ions occupy only tetrahedral sites. The isomer shift and magnetic hyperfine field indicate that the charge state of a Feion is ferric. Temperature dependence of the magnetic hyperfine field may be explained by the ferri-magnetic order in which two kinds of AB interaction are dominant and antiferromagnetic. Ne´el temperature is measured to be 281 K.

Alcohol Fermentation Characteristics of the Korean Native Mulberry (Morus spp.)

Ok Mi Kim,Seung-Mi Woo,Yong Kon Park,Yong-Jin Jeong 한국식품영양과학회 2006 Preventive Nutrition and Food Science Vol.11 No.2

This study was carried out to investigate the fermentation characteristics and optimum conditions for alcohol fermentation of the Korean native mulberry. The yeast strains of S. kluyveri DJ97, La parisienne (Saccharomyces cerevisiae, Netherlands) and Enoferm (Saccharomyces cerevisiae, Denmark) produced higher alcohol concentrations than other strains, and further study was therefore performed with these three species. The optimum additional water content for maximizing alcohol concentration was 250% (v/w). The alcohol concentrations were rapidly increased in the first 4 days under the optimum conditions and reached 13.8% for S. kluyveri DJ97, 14.0% for La parisienne and 14.0% for Enoferm, respectively. Residual sugar concentration was decreased steadily from the beginning of fermentation until 5 days, after which it maintained a constant level. The pH was decreased steadily in the log phase during further maturation. However, the pH underwent a slight decrease after 4 days and then was stabilized during further maturation. Methanol concentrations for the three species used were analyzed after 60 days maturation and were lower than the levels regulated by the food standard. Fusel oils such as n-propanol, iso-butanol, and iso-amyl-alcohol were produced as by-products with the highest production from Enoferm and the lowest from S. kluyveri DJ97.

Crystallographic and Magnetic Properties of Co_x(Cu_0.5Fe_0.5)_1-xCr_2S_4

Ok, Hang Nam,Baek, Kyung Seon,Sur, Jung Chul,Kim, Yun Kon,Hong, Sung Real 圓光大學校 基礎自然科學硏究所 1988 基礎科學硏究誌 Vol.7 No.3

x선 및 뫼스바우어 측정법을 사용하여 혼성 결정계열 Co(Cu_0.5Fe_0.5)_1-xCr_2S_4를 연구해본 결과. 결정구조는 입방스피넬구조를 갖고 있으며 격자상수는 Vegard의 법칙을 만족하고 있었다. 이성질체이동치로부터 철이온의 전하상태가 +3가 상태임을 알았다. 또한 전기사중극자 분열의 소멸로부터 철이온이 사면체자리를 차지하고 있음을 알았다. 특기할점은 80K에서 측정한 모든 뫼스바우어양들의 구성성분의 변화에 대해서 불변이라는 것이다. 이현상은 철이온 주변원자의 특이한 배치상태를 토대로 하여 설명할 수가 있다. Neel온도는 Co농도증가와 더불어 급속히 감소하였는데 이는 Co^2+-S-Cr^3+ 초교환 상호작용이 Fe^3+-S-Cr^3+ 초교환 상호작용에 비하여 상당히 약함을 의미한다. The mixed series Co_x(Cu_0.5)_(1-x)Cr_2S_4 has been studied using x-ray Mossbauer techniques. The crystal structure is found to be cubic spinel. and the lattice parameter a_0satisfies Vegard's law. The isomer shifts indicate that Fe ions are ferric and the absence of quadrupole splitting suggests the iron ions occupy. only tetrahedral sites. It is notable the all the Mossbauer Parameters at 80 K are independent of the com-position. This has been explained in terms of local atomic arrangements. The Neel temperature decreases rapidly with increasing cobalt concentration. suggesting that the superexchange interaction for the Co^2+-S-Cr^3+ link is much weaker than that for the Fe^3+-S-Cr^3+ link.

A Study on the Living Environment of the Residents of the Dementia Care Village

Ok Kon Moon,Dong Moon Yeum,Wan Suk Choi 국제물리치료연구학회 2018 Journal of International Academy of Physical Ther Vol.9 No.4

The purpose of this study was to investigate the relationship between the needs for environmental improvement and dementia patients' activity of daily living (ADL) and behavior and psychological symptoms of dementia (BPSD) in dementia patients living in urban type dementia care villages. The subjects of this study were 70 households with cognitive impairment and dementia among residents of dementia care village in Gunsan City. The survey was conducted with the permission of their family. Frequency analysis and descriptive statistical analysis were performed on the main variables to analyze the characteristics of the subjects. Bivariate correlation analysis was performed to verify the relationship between the two variables. According to the analysis results, the order of environment improvement was in the order of entrance (51.4%), toilet and stairs (48.6%), kitchen (11.4%), bedroom and laundry room (10.0%). In the relationship between the variables, The ADL was correlated with age (r=.315, p <.01), BPSD (r=.322, p<.01) and living environment inconvenience (r=.640, p<.01) while, living environment inconvenience correlated with environment improvement need (r=.669, p<.01). This study suggests that improvement of the residential environment of dwellers in dementia care villages, especially the stairway and entrance hall is necessary.

Mo"ssbauer study of CuCr_0.1Fe_1.9O_4

Ok, Hang Nam,Kim, Yun Kon 圓光大學校 基礎自然科學硏究所 1988 基礎科學硏究誌 Vol.7 No.3

CuCr_0.1Fe_1.9O_4 has been studied by Mossbauer spectroscopy and x-ray diffraction. The crystal structure is found to be a tetragonal spinel with the lattice parameters a_0=5.843 A and c_0 8.578 A . The Mossbauer spectra consist of two six-line patterns corresponding to Fe^3+ at the tetrahedral (A) and octahedral (B) sites. Debye temperatures for A and B sites are found to be 677±5 and 288±5 K, respectively. The intensity ratio of the A to B patterns is found to increase at low temperatures with increasing temperature due to the large difference of Debye temperatures of the two sites and to decrease at high temperatures due to migration of Fe^3+ ions from A sites to B sites.

A Study of Coupled Motion in Football, Baseball Players and General Students in Thoracic Spine

Ok Kon Moon 국제물리치료학회 2012 Journal of International Academy of Physical Ther Vol.3 No.2

The objective of this study is to provide basic information on coupled motions in thoracic spine during lateral bending from a neutral position for football and baseball players as well as for general university students. In the experiment, a total of 30 subjects participated(football players: 10, baseball players: 10, general students: 10). All subjects were in their 20’s. The subjects sat on a chair with lumbar support in a neutral position and bent to the right. As a result, for baseball players, coupled motions were observed in the opposite direction of the lateral bending in all parts of thoracic spine. For both football players and general students, coupled motions were observed in the same direction. These results confirmed that unilateral movements like baseball could affect coupled motions.

전기 재해의 통계 분석과 방지 대책에 관한 연구

오금곤,고광필 조선대학교 동력자원연구소 1990 動力資源硏究所誌 Vol.12 No.2

As the electric power consumption is increasing, the election of power supply voltages and the variety of electric apparatus bring about rigorous and frequent electric disasters, contrary to the conveniences of out dairly life. to prevent these disasters caused by electric appliance, the possible sources should be first analized and then countermeasures against those sources has t be followed. This paper provides logical methods by the more conmon causes may be identifie and localized and finally recommends countermeasures to prevent electric disaters.