PAN계 탄소섬유의 제조 및 탄화 조건에 따른 특성 분석

이현재,원종성,임성찬,이태상,윤준영,이승구,Lee, Hyun Jae,Won, Jong Sung,Lim, Sung Chan,Lee, Tae Sang,Yoon, Jun Young,Lee, Seung Goo 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.2

In this study, PAN (polyacrylonitrile)-based carbon fiber was prepared under different carbonization conditions. Carbonization of oxi-PAN fiber was performed under four different temperature conditions. Changes in the characteristics of these carbon fibers prepared under each condition were studied using various analyses. Crystalline characteristics of carbon fiber such as crystallinity and crystal size were analyzed using X-ray diffraction (XRD) and Scherrer's equation, based on the XRD patterns, respectively. The tensile strength and modulus of these carbon fibers were measured through a tensile test. Thermal characteristics were analyzed using a thermogravimetric analyzer (TGA). The result showed that the crystal size and crystallinity of the carbon fibers increased with carbonization temperature. Furthermore, both mechanical strength and thermal resistance were also observed to improve with carbonization temperature. Finally, a relationship between carbonization temperature, thermal properties, and mechanical properties of the carbon fibers was derived.

직장 여성의 불안, 충동성과 음주문제

이현재,한덕현,이영식,기백석,권해진,박두병,Lee, Hyun Jae,Han, Doug Hyun,Lee, Young Sik,Kee, Baik Seok,Kwon, Hye Jin,Park, Doo Byung 대한불안의학회 2011 대한불안의학회지 Vol.7 No.2

본 연구 결과 여성에서의 문제음주와 알코올 의존 비율이 남성보다는 적지만 9.8%로 상당수의 여성들이 알코올 문제를 겪고 있음을 알 수 있었다. 그리고 직장 생활을 하는 여성에서 음주 노출 기회가 더 많고, 실제로 음주에 대한 문제가 더 많이 발생하며 이는 여성의 상태불안과 충동성과 관계가 있다. 여성에서는 직업을 가짐으로써 음주 노출기회가 많아지고 직장 생활에서의 불안 및 충동성이 문제 음주를 일으키는 원인이 될 수 있음을 예상해 볼 수 있겠다. 따라서 직장 여성의 음주 노출 기회와 불안 및 충동성 조절이 음주 위험 요소의 중요한 조절 요인으로 생각된다. Objectives : This study examined drinking habits, anxiety, and impulsiveness in employed women. Methods : We sampled 925 residents aged over 20 years in Gwanak-gu of Seoul. In the process, we divided subjects into employed women and unemployed women groups and then used the Korean Version of Alcohol Use Disorder Identification Test (AUDIT-K), State-Trait Anxiety Inventory (STAI), and Barratt Impulsiveness Scale (BIS) to identify patterns in subjects' alcohol drinking, anxiety and impulsiveness. Results : Among the 925 respondents, 95.7% drank alcohol, and after the analysis, female problematic drinking ($12{\leq}AUDIT-K{\leq}25$) and alcohol dependence ($AUDIT-K{\geq}26$) was apparent in 61 (9.5%) and 2 respondents (0.3%), respectively. Female respondents who had jobs tended to drink more and exhibit higher ratios of problematic drinking, with a higher exposure to alcohol than those that were unemployed. The psychological attributes related to female respondents' alcohol problems related to state of anxiety and impulsiveness. Employed women respondents also showed a higher state of anxiety and impulsiveness than unemployed women. Conclusion : Controlling the frequency of exposure to alcohol, anxiety, and impulsiveness in employed women should be considered to be crucial controlling factors related to the hazards of excessive drinking.

전기방사에 의한 PVDF/PU 복합나노섬유의 제조 및 특성 분석

이현재,홍태민,임성찬,원종성,이승구,Lee, Hyun Jae,Hong, Tae Min,Lim, Sung Chan,Won, Jong Sung,Lee, Seung Goo 한국섬유공학회 2015 한국섬유공학회지 Vol.52 No.2

Bicomponent nanofibers with piezoelectric and latent-crimp properties were fabricated from two polymer solutions of polyvinylidene fluoride (PVDF) and polyurethane (PU) by electrospinning. Experimental conditions for electrospinning, such as applied voltage, solution concentration, and flow rate, were investigated to determine the optimal conditions for fabricating the bicomponent nanofibers. As a result, 21 wt% solution concentration, 0.5 ml/h flow rate, and 15 kV applied voltage were identified as optimum conditions for electrospinning the bicomponent nanofibers. The morphologies of the side-byside structure of the PVDF/PU fibers were observed. The formation of ${\beta}$-phase crystals by electrospinning was confirmed by Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Additionally, it was confirmed that the applied voltage does not have a significant effect on the formation of ${\beta}$-phase crystals. After the hydrothermal treatment, the ${\beta}$-phase crystalline content in the bicomponent fibers remained unchanged.

광 박테리아 색소체의 고정화에 의한 인위적 광 화학 반응조의 제조 및 응용

이현재,이동희,김수자 ( Hyun Jae Lee,Dong Hee Lee,Soo Ja Kim ) 생화학분자생물학회 1981 BMB Reports Vol.14 No.3

The bacterial chromatophores prepared from R. rubrum was immobilized by polyacrylamide entrapment to provide an efficient photosynthetic reactor for the generation of ATP and the reducing powers. The optimum yield of the immobilized chromatophores was obtained at the monomer concentration of 7.5% with its one-tenth amount of the crossfinking agent, The stability of chromatophores was improved markedly by the immobilization. The immobilized chromatophores showed the broad pH and temperature optimum at the pH range of 6.0 to 8.0 and at 40∼45℃, respectively, The temperature dependent deactivation constants for the native and immobilized chromatophores were estimated to be about 3.5×10-2 and 8.7×10-` per min, respectively, at 40℃. By immobilization, the original chromatophore activities including photophosphorylation of ADP and photoreduction of NAD^+ were increased markedly and the operational stability was also improved. The Km values of the photophosphorylation by the immobilized chromatophores were estimated to be 4.6×10^(-4) M and 2.7×10^(-3) M for ADP and inorganic phosphate, respectively, which were about 15 to 30 times higher than those for the native chromatophores, In addition, in the case of the succinatelinked photoreduction of NAD^+, the immobilization of chromatophores resulted in a marked stimulation, especially by the presence of KCN and oligomycin. Several other properties related to the photochemical reactions mediated by the immobilized chromatophores were also studied and compared with those of the native chromatophores.

인삼 유효성분에 관한 생화학적 및 약리학적 연구

이현재,한태룡,김수자 ( Hyun Jae Lee,Tae Ryong Hahn,Soo Ja Kim ) 생화학분자생물학회 1979 BMB Reports Vol.12 No.2

The biochemical efficacy of Panax ginseng was studied with the methanolic extract of ginseng by a new biochemical approach employing a rabbit muscle creatine phosphokinase (CPKase, EC 2.7, 3.1). The study included both effects of ginseng extract on the in vitro activity of CPKase and on tle tissue levels of phosphocreatine and ATP by in vivo administration. In this study, the activity of CPKase was measured in both directions of its reversible reactions with the corresponding coupled enzyme systems, and it was demonstrated that ginseng extract causes a marked acceleration in the rate of the in vitro activity of CPKase up to about two fold and shows a hyperbolic saturation curve in its concentration dependent relative activity profile of CPKase. In addition, from the in vivo experiment with mice, it was also demonstrated that the administration of ginseng extract orally causes an increase in the tissue level of phosphocreatine and thus prevents the decrease in the tissue content of phosphocreatine which goes along with a period of fasting the animals. From the results, it was also suggested that ginseng extract may affects on the energy-linked cellular metabolic reactions by promoting the activity of CPKase and thus causes an efficient utilization of high-energy phosphates for many cellular metabolic activities under the stressful conditions.

석회석을 원료로 사용한 재생용지의 친환경 In-situ Filler로서의 광학적 특성 연구

이현재,이로운,김춘식,남성영,서영범,안지환,Lee, Hyun-Jae,Lee, Lown,Kim, Chun-Sik,Nam, Seong-Young,Seo, Yung-Bum,Ahn, Ji-Whan 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.2

The study was performed with low-grade limestone, which is used to make cement or is disposed of due to its low CaO content. In this study, the optimal condition of limestone with which to manufacture precipitated calcium carbonate (PCC) and limestone in fiber was determined through in-situ reactions. The best firing condition is with slaked lime with rapid cooling after 2 h of firing at $1000^{\circ}C$. In addition, the content of CaO can be increased by sorting the low-grade limestone using a 200 mesh filter, and the optical quality of old newspaper (ONP) was similar when using both low-grade and high-grade limestone. Also, controlling the particle size of PCC is an important factor pertaining to the optical characteristics of paper.

Biochemical and Pharmacological Study on The Bioactive Principles of Panax Ginseng

이현재,한태룡,김수자,Lee, Hyun-Jae,Hahn, Tae-Ryong,Kim, Soo-Ja 생화학분자생물학회 1979 한국생화학회지 Vol.12 No.2

인삼유효성분에 의한 강장 효과를 생체내 에너지 대사 과정과 연관시켜 새로운 생화학적 및 약리학적 견지에서 연구 검토하였으며, 이의 중요 결과는 다음과 같음. 즉 인삼의 메타놀 추출물은 토끼 근육으로 부터 유리한 효소인 creatine phospkokinase(CPKase)의 활성도를 증가시킴을 알았으며, 이러한 활성도의 증가 또는 활성화는 인삼 추출물의 농도에 따라 변화하되 약 5mg/ml 농도 이상에서는 최대 활성화율인 약 2배 정도로 유지됨을 알았다. 아울러 생체 투여 실험에 있어 생쥐에 인삼 추출물을 4주간 투여 (10mg/day)한 경우 심장 근육 조직 내의 phosphocreatine의 함량이 현저히 증가 되었으며 이런 현상은 동물을 36시간 동안 굶겼을 경우에도 대조군보다 높은 값을 유지됨을 알았다. 이러한 인삼추출물에 의한 효과는 세포내 에너지 대사과정과 밀접한 관계를 맺고 있다고 추정할 수 있었으며 인삼 유효성분의 주요 약효를 에너지 대사와 관계된 강장 효과로서 설명코져 시도하였음. The biochemical efficacy of Panax ginseng was studied with the methanolic extract of ginseng by a new biochemical approach employing a rabbit muscle creatine phosphokinase (CPKase, EC 2.7, 3.1). The study included both effects of ginseng extract on the in vitro activity of CPKase and on the tissue levels of phosphocreatine and ATP by in vivo administration. In this study, the activity of CPKase was measured in both directions of its reversible reactions with the corresponding coupled enzyme systems, and it was demonstrated that ginseng extract causes a marked acceleration in the rate of the in vitro activity of CPKase up to about two fold and shows a hyperbolic saturation curve in its concentration dependent relative activity profile of CPKase. In addition, from the in vivo experiment with mice, it was also demonstrated that the administration of ginseng extract orally causes an increase in the tissue level of phosphocreatine and thus prevents the decrease in the tissue content of phosphocreatine which goes along with a period of fasting the animals. From the results, it was also suggested that ginseng extract may affects on the energy-linked cellular metabolic reactions by promoting the activity of CPKase and thus causes an efficient utilization of high-energy phosphates for many cellular metabolic activities under the stressful conditions.

지반조사에 의한 함안군 도항리 6호 고분 특성 규명

이현재,함세영,박삼규,이충모,오윤영,웨이밍량,Lee, Hyun-Jae,Hamm, Se-Yeong,Park, Samgyu,Lee, Chung-Mo,Oh, Yun-Yeong,Liang, Wei Ming 대한자원환경지질학회 2015 자원환경지질 Vol.48 No.4

지질학적, 물리탐사기법, 지질공학적 방법을 통하여 함안군 도항리 6호고분의 축조 형태, 고분 축조에 사용된 재료의 원산지와 공학적 성질, 봉분과 석실부에 대한 안정성 등을 고찰하였다. 고분의 기반암인 함안층은 풍화를 받아 인력으로 굴착이 용이한 암반 특성을 나타내었다. 전기비저항 탐사에 의하면 봉분은 토사부를 나타내는 저비저항대와 암석편의 함량이 많은 암석부의 고비저항대로 구분되었다. 대부분의 석실부 개석은 함안층과 동일한 암석으로 구성되어 있으나, 개석의 일부는 연구지역의 최남단에서 산출되는 흑운모화강암과 동일하다. 토질 시험에 의하면, 봉분의 토사부는 낮은 함수비, 낮은 간극비, 적정한 단위중량으로 보아 다짐 정도가 매우 높은 재료임을 지시한다. 또한 봉분의 암석부의 강도는 일반적인 암반의 전단강도를 초과하고 있어 매우 안정성 있게 유지되고 있는 것으로 해석된다. Hamangun Dohangri $6^{th}$ tumulus was characterized by using geological, geophysical, and geotechnical surveys in terms of the shape of the tombs, origin and geotechnical properties of tomb materials, safety of grave mound and burial chamber. The bedrock (Haman Formation sedimentary rock) forming the ground of the tomb, is weathered such that men can excavate the ground. The mound tomb is classified into soil part and rock part by low resistivity and high resistivity, respectively, through electrical resistivity survey. The burial chamber is mostly made by Haman Formation while some part is composed of granitic rock that is distributed in the most southern district of the study area. According to soil tests, the soil part of mound tomb shows low water content, low pore ratio, and proper unit weight that indicate highly compacted material. Additionally, the mound tomb is safe because the strength of the rock part of the mound tomb exceeds that of general rock.

Histidylleucine Hydrolyzing Enzyme : A Dipeptidase From Hog Lung

이현재,박중근,Hyun-Jae Lee,Jung-Keun Park Korean Chemical Society 1975 대한화학회지 Vol.19 No.5

돼지의 폐(lung)로 부터 histidylleucine dipeptide를 가수분해 시키는 효소를 추출 정제 하였으며, 정제된 효소의 비활성도는 $1.6{\mu}moles$/min/mg protein(약 50배 정제)이었다. 이 새로운 dipeptidase의 분자량은 sucrose density gradient 원심침강법에 의하여 측정한 결과 약 80,000 daltons이었으며 효소의 기질 물질로서 요구되는 조건은 방향족 잔기를 갖는 dipeptide를 필요로 하나 histidylleucine을 기질로 사용하였을 경우 $K_m$ 값은 $2{\times}10^{-4}M$이었다. 본문에서는 이효소의 일반적 특성과 그 밖의 생리학적 및 생화학적 기능에 관하여 검토하였다. An enzyme capable of hydrolyzing histidylleucine was purified 50 fold from hog lung. The final preparation hydrolyzed $1.6{\mu}moles$ of histidylleucime per minute per mg of protein. The $K_m$ of the enzyme for the enzyme was found to be $2{\times}10^{-4}M$. The enzyme was required a number of free dipeptides for the substrate specificity, and was inhibited by EDTA and 1,10-phenan-throline. The molecular weight of the enzyme was estimated to be 80,000 daltons from sucrose density gradient sedimentation analysis. The corrected $s_{20,w}$ value was 5.3 S.

S-Hippuryl Thioglycolyl Glycine : A New Chromogenic Substrate for Dipeptidyl Carboxypeptidases

이현재,Lee Hyun-Jae Korean Chemical Society 1975 대한화학회지 Vol.19 No.4

Dideptidyl carboxypeptidases와 angiotenisn-coverting enzyme의 새로운 기질불질로서 thiol ester 인 S-Hippuryl thioglycolyl glycine을 합성하였으며, 이 기질에 의한 간편하고도 예민한 효소 활성도의 정량방법을 제시하였다. 이 경우 효소반응 생성물인 thioglycolyl glycine은 반응계중에 첨가한 5,5-dithio-bis-(2-nitrobenzoic acid), DTNB와 쉽게 반응하여 410nm에서 강한 흡광스펙트럼을 갖는 5-thio-2-nitrobenzoic acid(${\varepsilon}M=1.36{\times}10^4$)을 형성함으로서 효소의 새로운 미량정량 방법으로 이용 가치가 크다고 본다. A spectrophotometric assay technique is descriead for the measurement of free SH-groups in the enzyme reaction mixture. The method utilizes a new substrate, S-hippuryl-thioglycolyl-glycine(S-Hip-thioglycol-Gly) which is the basis for a convenient assay of angiotensin-converting enzyme and other dipeptidyl carboxypeptidases. This substrate contains an appropriately located thioester linkage that is hydrolyzed by the converting enzyme and other dipeptidyl carboxypeptidases. One of the products, thioglycolyl glycine, is readily measured by reaction with Ellman's reagent, 5,5'-dithio-bis-(2-nitrobenzoic acid), DTNB, to produce 5-thio-2-nitrobenzoic acid which has a strong absorption band at 410 nm. The method is sensitive (${\varepsilon}M = 1.36{\times}10^4$ at 412 nm) and can be applied as a continuous recording with DTNB present in the enzymatic reaction mixture.