PTT단위를 갖는 액정중합체의 합성 및 블렌드

김원,최유성,이태양,최재곤,홍완해,조병욱 조선대학교 생산기술연구소 2003 生産技術硏究 Vol.25 No.1

This study explores the potential of improving the physical properties of poly(trimethylene terephthalate) (PTT) by inducing thermotropic liquid crystalline polymers. The TLCP was synthesized by polycondensation reaction of terephthaloyl chloride with corresponding diols. The TLCP used was copolymers containing random PTT groups on the polymer backbone. The PTT moieties were used to increse compatibility between the PTT and the TLCP. The TLCP showed the nematic phase above those melting temperature(T_m) The TLCP seems to act as plasticizers and nucleating agents in the matrix polymers Liquid crystalline phase did not reaveal any significant macrophase separation and thermal degradaton under the temperature of processing condition.

經緯系의 收縮에 關한 硏究

金熙山,李在坤 忠南大學校 1962 論文集 Vol.2 No.-

In general, the contraction of thread in a fabric can be determined by the following factors such as tension, ends or picks per inch, weaves, counts and turns per inch. In order to simplify the calculation we ignored the effects of tension and twists on contraction, and classified the fabric as follows: a) a square fabric b) a fabric whose angle of curvature of warp or weft proceeds the other. c) a fabric whose angle of curvature of warp or weft slightly differes from the other. Firstly, we determined the maximum possible density of warp or weft as follows: D=1/cosθ(de+df) where θ; angle of curvature de; dia. of warp df; dia. of weft D; maximum possible density of warp and weft. The results are as follows L = {I×C×(de+df)×n/D}×D/N where L; original length of warp or weft in a unit length of fabric. I; number of curvature in a repeat due to weaves. C; constant of angle of curvature. n; number of threads that continuously float in a repeat due to weave. And on the variation of tension during weaving we analysed the variation of tension due to three principal motion of loom and classified the nature of variation as follows; such as a) tension which varies continuously during weaving b) tension which varies intermittenly during weaving And summerized as follows; A) tension which varies according to shedding and beating motion varies intermittenly B) tension which added to the warpbeam increases by the decrease of warp beam dia. C) tension which varies according to letting off and taking up motion varies intermittently or continuously by the mechanism.

복합 관동맥병변에서의 Rotational Atherectomy : 초기결과

김진우,박성욱,홍명기,이상곤,이일수,이철환,최기준,강덕현,송재관,김재중,박승정 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.9

Organoclay/TLCP nanocomposites의 제조 및 특성

김원,최재곤,조병욱 조선대학교 생산기술연구소 2003 生産技術硏究 Vol.25 No.2

The organoclay/TLCP(Thermotropic Liquid Crystal Polymer) nanocomposites were prepared by in-situ polymerization. To discuss the effect of the organoclay contents on the polymer properties, we prepared organoclay/TLCP nanocomposites of 2, 5, 10wt% in organoclay contents. The organoclay/TLCP nanocomposites were characterized by scanning electron microscopy(SEM), X-ray diffractometer(XRD), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and thermogravimetric analyzer(TGA). The bending moduli of organoclay/TLCP nanocomposites were improved with increasing organoclay contents. The TLCPs and organoclay/TLCP nanocomposites showed the nematic phase above those melting ternperature(T_(m)). The TLCPs and organo clay/TLCP nanocomposite seem to act as plasticizers and nucleating agents in the matrix polymers.

폴리스타이렌 아이오노머와 액정중합체 블렌드의 기계적 성질

김희석,김준섭,최재곤,박기주,윤용국,진정일 조선대학교 생산기술연구소 1997 生産技術硏究 Vol.19 No.1

The dynamic mechanical properties of thermotropic liquid crystalline polyester (LCP) blends with polystyrene (PS) and Li sulfonated polystyrene (PSSLi) were investigated. It was found that PS forms an immiscible blend with LCP. However, above the matrix T_(g) of the PS, the addition of the LCP increases the modulus of the blend significantly because the LCP acts as filler below its T_(g). In PSSLi/LCP blend system, it was also found that, in the temperature range between two T_(g)s of the ionomer, the LCP acts as filler and thus increases the modulus of the blend. However, the filler effect of the LCP on the modulus decreases rapidly with increasing temperature and disappears above the T_(g) of the LCP. Finally, it was suggested that the PSSLi may be partially miscible with the LCP via ion-dipole interactions between a Li^(+) cation of the PSSLi and a carbonyl group of the LCP.

EVA Nanocomposites 제조 및 특성연구

김영용,박일수,정효선,최재곤,김정규,조병욱 조선대학교 생산기술연구소 2003 生産技術硏究 Vol.25 No.1

Ethylene vinyl acetate random copolymer(EVA)/layered-silicate nanocomposites were prepared by melt or solution blending. The TGA thermograms of EVA/ layered-silicate nanocomposites showed an improved thermal stability as the layered-silicate contents increased. The decomposition temperature of nanocomposite was increased around 10℃ compared with pure EVA at 50% weight loss under N_2 atmosphere And in an air atmosphere, temperature difference in 50% wt loss between the nanocomposlte and the virgin EVA was around 100℃ The moduli in their thermomechanical module of nanocomposite are higher than pure EVA. Interlayered spacings of nanosilicates were slightly increased when prepared by melt blending. On the other hand, they were remarkably increased when prepared by solution blending. It may be explained that EVA moiety of the copolymer showed partial adsorption behavior on the surface layer of the silicate. It also revealed that the adsorption is more effective in the solution blending than in the melt blending.

영산강본류 중류 수계의 어류상에 대하여

송태곤,김재근 木浦大學校 沿岸環境硏究所 1995 沿岸環境硏究 Vol.12 No.1

The freshwater fish fauna was investigated from June 27, 1992 to November 23, 1995 at 53 stations in the middle streams of Yongsan River system. Total fishes collected from them were 12 families, 33 genera, 42 species and subspecies, 14, 699 individuals including 27 species belonging to Cyprinidae, and among them, 9 species were known as Korean endemic species. In this river, the abundant species were Pseudorasbora parva, Rhodeus uyekii, Microphysogobio yaluensis, and Zacco platypus, and the rare species were Abbottina springeri, Pseudobagrus fulvidraco, Macropodus chinenesis, Monopterus albus, and Cobitis longicorpus.

고사리(Pteridium aquilinum)뿌리 전분의 이화학적 특성에 관한 연구 : 제2보 : 전분의 물리적 특성 Ⅱ. Physical Properties

曺哉銑,金成坤,李啓瑚,權泰完 경희대학교 부설 식량자원개발연구소 1981 硏究論文集 Vol.2 No.-

고사리뿌리 전분의 이화학적인 특성연구의 일환으로 실시된 물리적 특성시험 결과는 다음과 같다. 전분입자의 미구조의 결합력을 보기 위한 흡수도, 팽운력, 용해도 시험결과 감자전분이나 타피오카전분보다 강한 결합을 하고 있으며 곡류전분보다는 약하며 팽윤력이 single-stage pattern을 이루고 있었다. 가열에 의한 전분입자의 복굴절성 상실, α-아밀라아제에 의한 소화성 및 X-선 회절둥으로 전분의 호화과정을 살펴본 결과 55-60℃에서 호화가 시작되고 60~70℃에서는 95%이상 호화되었다. 또한 3~6%전분용액의 가열에 따른 점도변화를 amyl-ograph를 사용하여 실험한 결과 pasting temperature 62~68℃, 최고점도 80~840BU, 50℃로 냉각후의 점도는 110~555BU였다. 따라서 다른 전분에 비해서 점도가 낮으나 setback이 현저히 느렸다. 수분함량 50%의 전분겔의 경도는 팥 전분보다는 약하고 감자나 밀전분에 비해서는 현저히 높았다. 전분겔의 저장중 노화속도는 밀 전분보다는 느리고 파지오카 전분보다는 빨랐다. 고사리뿌리 전분은 팥 전분겔특성에 큰 변화를 주지않지만 노화를 억제하였고 밀 전분겔에 첨가시에는 겔의 경도가 저하되어 부드러워지는 경향을 보였다. The gelatinization phenomena of bracken root starch were examined by means of the loss of birefringence, degree of digestibility by amylase and X-ray diffraction. These results indicated that gelatinization temperature of the starch was 55∼60℃ and over 95% of starch were gelatinized at the temperature between 60 and 70℃. The swelling power of the bracken root starch was much less steeper than that of potato or tapioca starch. Amylograph data on the various starch concentrations showed the pasting temperature of 62∼68℃, peak height of 80∼840 Brabender unit (BU) and peak after cooling to 50℃ of 110∼555 BU. According to the information obtained from amylograph data, the bracken root starch showed low set back. The rate of retrogradation of the starch as tested by Texturometer was slower and faster than potato and tapioca starches, respectively.

다포계형식 건축물의 이방에 관한 연구

박언곤,한욱,김재국 대한건축학회 2004 대한건축학회논문집 Vol.20 No.7

This study is on the Korean wooden architecture's Corner Bracket Sets(Gui-kongpo) and one of these elements "Yibang(耳枋)". The Purpose of this study is to understand the relationship between "Yibang(耳枋)" and Korean wooden architecture's structure system. To conduct this research , it is important to analysis its type and structure system in korean wooden architecture "Dapogye". The basic conceptions of "Yibang(耳枋)" are sought, its character and shape is actual surveyed through 140s object buildings in this study. In result, first of all, Using period of "Yibang(耳枋)" is Chosun dynasty and "Yibang(耳枋)" appears in wooden architecture style "Dapogye". Second, the size of roof isn't related with "Yibang(耳枋)", and it's duty is up to Corner Bracket Sets(Gui-kongpo). Third, the buildings with "Yibang(耳枋)" get more 'numerical value ; a2/b' than buildings without "Yibang(耳枋)".

화상으로 인한 소구증 환자의 치험례

지재휴,이병준,김영균,김수관,황경곤,여환호,박인순 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.3

Deep burns of the face & lips often lead to scarring and contraction of the circum-oral tissues with a marked reduction in the size of the oral aperture. Such burns most commonly caused by electrical contact, for example, children sucking electric plugs, or as a result of chemical burns and the exposture to flame. Once having burns, burned tissue may contract and reduce considerably the size and mobility of the mouth ; therefore bring up the resultant functional disturbance, verbal difficulty, even disgestive difficulty, and poor appearance, which fall into difficulty in social acceptability, caused by burns. In our department, 2 patients who were complain of functional limitations and esthetic problem owing to scar contracture, were visited, and we treated this microstomia with scar excision, graft and flap technique, and postoperative intensive physical therapy. We obtained relatively favorable results, thus report this cases with literature review.