반응성 단량체로서의 고순도 로진 - 말레산 부가물의 합성

최형기,김점식,안성태 ( Hyeong Ki Choi,Jum Sik Kim,Sung Tae Ahn ) 한국공업화학회 1994 공업화학 Vol.5 No.2

로진과 말레산무수물로부터 rosin-maleic anhydride adduct(RMA)를 합성하였다. 중합반응의 단량체로서 이용하기 위한 고순도의 RMA의 합성에는 정재공정을 수반하는 용융합성법과 정제공정이 불필요한 용액합성법을 이용하였다. 용액합성법에서 합성한 RMA의 수율이 용융합성법보다 높았다. 용융합성법의 최고수율은 40%였으나 사염화탄소 및 아세트산을 반응용제로하는 용액합성법에서 얻은 생성물의 수율과 순도를 검토한 결과 비교적 고순도의 RMA를 얻을 수 있었고, 수율은 사염화탄소 용제법의 경우 48%(이론수율 87.6%), 아세트산 용제법의 경우 51% (이론수율 94%)였다. Rosin-maleic anhydride adduct(RMA) was synthesized from rosin and maleic anhydride. Highly purified RMA for the application of polymerization monomer was synthesized by means of two methods ; the melt reaction followed by further purification and the solution reaction. As a result of this study, the solution reaction was better than the melt reaction for obtaining higher yield of RMA. Maximum yield of RMA obtained by the melt reaction was only 40%. But the yield of RMA obtained by the reaction in carbon tetrachloride solution was 48% (theoretical yield 87.6%) and that obtained by the reaction in acetic acid solution was 51.5% (theoretical yield 94%) respectively.

폴리이미드의 합성과 필름의 물성에 미치는 디아민과 용매의 효과

최형기,이호식,정창남,김점식 ( Hyeong Ki Choi,Ho Sik Lee,Chang Nam Chung,Jum Sik Kim ) 한국공업화학회 1991 공업화학 Vol.2 No.3

폴리이미드의 전구체인 폴리아믹산을 benzophenone tetracarboxylic dianhydride (BTDA)와 4, 4`-diamino diphenyl methane (MDA) 혹은 MDA와 3, 3`-dimethyl benzidine (OTB)의 혼합디아민과 용액축중합반응에 의하여 합성하였다. 반응용매로는 m-cresol과 m-cresol/xylene의 혼합용매를 사용하였다. TGA 분석 결과 폴리이미드 필름은 초기분해 온도가 540 ℃-590 ℃의 범위로서 내열성이 우수하였다. DSC 분석으로 중합체의 유리전이온도는 340 ℃ 이상임을 확인하였다. 폴리이미드 필름은 양호한 기계적, 전기적 물성 값을 갖는 시료에서 인장강도가 16Kg/㎟ 이상이었고, 절연파괴전압이 200KV/mm 정도였다. 대체로 MDA 만을 디아민으로 사용한 단일중합체보다 MDA/OTB 공중합체의 물성이 우수하였고, m-cresol에서 합성한 중합체보다 m-cresol/xylone 흔합용매계에서 합성한 중합체의 물성값이 우수하였다. Polyamic acids, precursor polymers of polyimides have been obtained by the solution polycondensation of benzophenone tetracarboxylic dianhydride (BTDA) with 4,4`-diamino diphenyl methane (MDA) and/or 3, 3`-dimethyl benzidine (OTB). The reaction was carried in two solvent systems such as m-cresol and m-cresol/xylene mixture. The results of TGA analysis showed that the polyimide films had good thermal stability with the initial decomposition temperature ranging from 540 ℃ to 590 ℃. According to DSC analysis of polymers, the glass transition temperature was over 340 ℃. Polyimide film samples, showed good mechanical and eletrical properties, had over 16 Kg/㎟ of tensile strength and about 200 KV/mm of dielectric breakdown voltage. The properties of the copolymer from MDA/OTB were better than those of the homopolymer from MDA. And the polymer synthesized in m-cresol had lower properties than that obtained in m-cresol/xylene.

오존을 이용한 불포화 색소물질의 탈색반응

최형기,정창남,김점식 ( Hyeong Ki Choi,Chang Nam Chung,Jum Sik Kim ) 한국공업화학회 1991 공업화학 Vol.2 No.3

β-Carotene의 오존산화반응을 통하여 불포화 색소물질에 대한 오존의 탈색효과와 반응성분의 변화를 정량 적으로 비교하였으며, 카로티노이드계 색소가 주요 발색원인물질인 beeswax에 대한 오존의 산화반응을 물, 0.5%와 1.0%수산화나트륨수용액, 20%와 95%초산수용액에서 실시하여 각 반응계에 따른 탈색효과를 비교검토하였고 과산화수소의 첨가효과도 검토하였다. β-Carotene의 불포화이중결합의 감소와 탈색효과는 정량적으로 비례하였으며 beeswax의 탈색효과도 잘 일치하는 결과를 얻었다. Beeswax의 탈색효과는 1.0% 수산화나트륨수용액에서 반응한 것이 가장 우수하였으며, 과산화수소의 첨가(왁스의 2%)시 390nm에서의 흡광도가 0.045로 좋은 탈색효과를 얻을 수 있었다. Beeswax의 탈색에 있어 오존산화반응이 물리흡착보다 효과적이라는 결론을 얻을 수 있었다. Bleaching effect of ozone on unsaturated coloring material was compared quantitatively with the change of composition of reactants through the ozone oxidation of β-carotene. Beeswax colorized by carotenoids was reacted with ozone in water, 0.5% and 1.0% sodium hydroxide solution, and 20% and 95% acetic acid solution and bleaching effect of each reaction condition was compared with each other. And then the additive effect of hydrogen peroxide was investigated. Decrease of unsaturated double bond of β-carotene was proportioned quantitatively to the bleaching effect of ozone on β-carotene and was in accordance with the bleaching effect on beeswax. The bleaching effect of ozone on coloring material in 1.0% sodium hydroxide solution was better than any other condition and the absorbance of beeswax at 390 nm was improved to 0.045 with the addition of hydrogen peroxide(2% of wax). For the bleaching of beeswax, it was concluded that the ozone oxidation was more effective than physical adsorption.

파파베린과 테크니시움을 이용한 음경발기촬영술

최형기,정병하,Choi, Hyung-Ki,Chung, Byung-Ha 대한생식의학회 1986 Clinical and Experimental Reproductive Medicine Vol.13 No.2

To estimate the penile blood flow changes during artificial with erection intracorporeal papaverine injection, we injected 99 m Technitium-Human Serum Albumin via antecubital vein simultaneously and calculate the radioisotope activity of the penis using computerized Gamma Camera. We classified the results into 3 groups according to the transit time, erection persistent time and venous index in 67 impotence patients. We defined the arteriogenic impotence with the delayed transit time (more than 600 seconds) in 13 patients and venogenic with the shortened erection persistant time (less than 200 seconds) and decreased venous index (less than 0.8) in 11 patients. The rest of them (43 patients) were regarded as equivocal impotence, probably nonvasculogenic or psychogenic.

인지적 청각 특성을 이용한 고립 단어 전화 음성 인식

최형기,박기영,김종교,Choi, Hyung-Ki,Park, Ki-Young,Kim, Chong-Kyo 대한전자공학회 2002 電子工學會論文誌 IE (Industry electronics) Vol.39 No.2

본 논문에서는, 음성 인식률 향상을 위하여 청각 특성을 기반으로 한 GFCC(gammatone filter frequency cepstrum coefficients) 파라미터를 음성 특징 파라미터로 제안한다. 그리고 전화망을 통해 얻은 고립단어를 대상으로 인식실험을 수행하였다. 성능비교를 위하여 MFCC(mel frequency cepstrum coefficients)와 LPCC(linear predictive cepstrum coefficient)를 사용하여 인식 실험을 하였다. 또한, 각 파라미터에 대하여 전화망의 채널 왜곡 보상기법으로 CMS(cepstral mean subtraction)를 도입한 방법과 적용시키지 않은 방법으로 인식실험을 하였다. 실험 결과로서, GFCC를 사용하여 인식을 수행한 방법이 다른 파라미터를 사용한 방법에 비해 향상된 결과를 얻었다. In this paper, we propose GFCC(gammatone filter frequency cepstrum coefficient) parameter which was based on the auditory characteristic for accomplishing better speech recognition rate. And it is performed the experiment of speech recognition for isolated word acquired from telephone network. For the purpose of comparing GFCC parameter with other parameter, the experiment of speech recognition are carried out using MFCC and LPCC parameter. Also, for each parameter, we are implemented CMS(cepstral mean subtraction)which was applied or not in order to compensate channel distortion in telephone network. Accordingly, we found that the recognition rate using GFCC parameter is better than other parameter in the experimental result.

합성 물질의 종류 및 몰비 변화에 따른 LiMn2O4 의 전기화학적 특성

최형기,박현배,정인성,구할본 ( Hyung Ki Choi,Hyun Bae Park,In Seong Jeong,Hal Bon Gu ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1

일자리 창출을 위한 지역·산업 맞춤형 인력양성 수요조사 연구 : “강원도 영서지역 중심으로”

최형기(Hyung Ki Choi) 산업기술교육훈련학회 2016 산업기술연구논문지 (JITR) Vol.21 No.2

The purpose of this research is to analyze the basic sources to open the education program focused on demanding through a local Industry customized manpower cultivation demand survey which is to solve mutual problem on labor shortage and job seeking as well as professional man power training which aims to reach a 70% of employment rate by governmental support such as localized job creation for small-medium size enterprises necessary for the new technology and skilled labors and the young prospective graduate and the non-employed in Western Gangwon Province Residences, and the literature research method.

자동차용 고분자의 재활용 기술동향

최형기(Hyeong Ki Choi),이용무(Yong Moo Lee) 한국고분자학회 1995 고분자 과학과 기술 Vol.6 No.4

발기부전환자에서 홍삼 복용후의 음경혈류와 발기력 변화

최형기(Hyung Ki Choi),최영진(Yeong Jin Choi),김장환(Jang Hwan Kim) 고려인삼학회 2003 Journal of Ginseng Research Vol.27 No.4

The clinical efficacies of Korean Red Ginseng for improving sexual function has been reported only by selfreporting questionnaires.AVS-Penogram is a method evaluating natural penile blood flow changes by Gamma-camera after intravenous injection of Techmetium 99m-RBC and also stimulating by erotic video tape. To more objectively evaluate the efficacies of Korean Red Ginseng for erectile function, we applied AVS-Penogram as a objective diagnostic tool. AVS-Penogram studies were done in 28 patients with erectile dysfunction after administration of Red Ginseng(19) or placebo(9) group.The pattern of AVS-Penogram before medication were normal type in 4, impossible in 2, unstable in 20, delayed in 1, and mixed in 1. The unstable type were the most prevalent observed in 71.4% of all patients.The patterns of AVS-penogram were 2. 2. 13. 1 in Red Ginseng group, while in placebo group normal 2, unstable 7. After 4 weeks in Red Ginseng group, there were 3 cases of improved penogram findings, while only 1 in placebo group. There were no statistical significancies in the type of penogram changes on both group.But the maximum radioactivity were improved in 11<br/> patients(57.9%) in Red Ginseng group, while 2(22.2%) in placebo group. There were statistical significancies in comparing the maximal radioactivity of penogram on both group. These AVS-Penogram findings shows, encouraging results of by increased penile blood flow Korean Red Ginseng our medication. Further study is more needed to re-confirm these results by more concentrated active formulations of sapanonin & other active ginsenosides. These promising results will lead to develop a new remedy for erectile dysfunction by Korean Red Ginseng.

음성 보안 시스템 구현에 관한 연구

최형기 ( Hyung-ki Choi ),박기영 ( Kee-young Park ) 한국고등직업교육학회 2002 한국고등직업교육학회논문집 Vol.3 No.2

This paper has performed the speech security system which is operated by software program using DTW based text prompt speaker verification algorithm in accordance with 12th gammatone filter frequency cepstrum coefficients for feature parameter. This realized system has operated sequentially as below: Users utter the proposed words, the uttered word is transformed as the feature parameters, the pattern is compared with the already stored reference pattern and could decide the user's availability whether use it or not. This research executed 10 words from 15 speakers as test data for the security system, experimentally. The result showed FA 10.2% and FR 8.84% respectively, which are average errors in the simulated experimental circumstances.