펄프 공장 내의 수질 오염 방지

백기현 高麗大學校 自然資源科學硏究所 1995 自然資源科學硏究 Vol.3 No.-

저급목재의 자기가수분해 전처리에 의한 고순도 셀룰로오스 기질의 제조

조남석,김병로,백기현 한국목재공학회 2002 목재공학 Vol.30 No.4

본 연구는 자기가수분해전처리를 통하여 반응성이 높은 고순도 셀룰로오스기질을 제조하기 위하여 수행되었다. 공시재의 일반 화학조성은 일본잎갈나무와 신갈나무간에 큰 차이가 있음을 알 수 있었다. 추출물함량은 일본잎갈나무가 신갈나무보다 상당량 많았다. 특히 냉·온수 추출물함량은 2.5∼3.5배 많았다. 이러한 추출물함량의 큰 차이는 일본잎갈나무에는 arabinogalactan이 많이 함유되어 있기 때문인 것으로 사료된다. 리그닌함량은 신갈나무가 잎갈나무보다 5% 정도 낮았으며, 그 대신 홀로셀룰로오스 및 펜토산함량이 각각 3% 정도 높은 값으로 나타났다. 22 ㎏/㎠ 수증기압력에서 5∼60분간의 자기가수분해 전처리과정에서 glucose 함량에는 변화가 없었으나, hemicellulose 및 lignin 함량은 급격한 변화를 보였다. 전처리과정에서 가수분해물의 pH는 3까지 저하되었으며, 이러한 경향은 신갈나무 및 일본잎갈나무에서 동일하게 나타났다. Sodium chlorite 및 sulfite 혹은 bisulfite 전처리 후 자기가수분해가 리그닌함량이 낮은 고순도셀룰로오스기질의 제조에 효과적이었다. 특히 자기가수분해처리재를 알칼리 및 산소-알칼리 2단처리함으로서 0∼0.2%의 리그닌함량을 가지는 고순도기질을 제조할 수 있었다. This study was performed to produce the high reactive lignin zero substrates from autohydrolyzed wood resources. In chemical compositions of used raw-materials, there were significant differences between two species, Japanese larch (Larix leptolepis) and oak (Quercus mongolica) woods. Japanese larch contained 2.5 to 3.5 times higher amounts of extractives than oak wood, which is mainly derived from high content of arabinogalactan in Japanese larch wood. Oak wood has 5% lower lignin content and 3% higher holocellulose and pentosans than larch wood. Concerned to changes in wood components during autohydrolysis pretreatment at 22 ㎏/㎠ steaming pressure for 5∼60 min, glucose content was constant during pretreatment, while hemicellulose and lignin were abruptly changed. Hemicellulose fraction was decreased significantly and lignin contents increased because of its condensation reaction with hemicellulose degradation products. The pH of hydrolyzates during pretreatment was decreased, reached upto pH 3 and since then leveled off. In the case of oak wood, same tendency was observed as in Japanese larch. Autohydrolysis followed by sodium chlorite and sulfite or bisulfite pretreatment was very effective in delignification of the substrates. In particular, two-stage delignification of autohydrolyzed woods with alkali and O_2-alkali resulted in very low lignin content substrates, such as 0∼0.2% lignin substrate.

정신과 의약분업에 대한 5년 후 추적조사

박정수,정재열,홍진표,백기청,박영현,박종익 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.4

Objectives : This study is designed to discuss the pros and cons related to the 'separation of drug prescription and dispensation' system when 5 years have passed by since the introduction of this system. Methods : The 592 psychiatrists from 1,107 working places took part in nationwide survey by mail or E-mail from June to September, 2005. The response rate was 23.8%, most of respondents came from private clinics. Results : The average age of psychiatrist was 44.6 years old, ranging from 25 to 75, most of them was predominantly male. The main results were as followings : 1) The ratio of psychiatric prescription out of hospital based on out-patients departments was the lowest in clinics, following by hospitals, general hospitals and university hospitals by order. 2) The main reasons of customer's preference for out of hospital prescription were economic advantage and self-awareness of prescription. As for the disliking for it, the most complaints were the anxiety about disclosure of psychiatric treatment, in convenience for delay and concern about drug change. Conclusion : Five years didn't seem to give a change on how the psychiatrists perceive the 'separation of drug prescription and dispensation' system at all. The confidentiality and human right issues on the part of psychiatric patients should never be ignored in order to manage this system successfully.

A new flavanone from the wood of Amorpha fruticosa

PAIK Ki-Hyon,CHOI Don-Ha,KANG Ha-Young,LEE Hak-Ju,LEE Hyun-Jung 大韓藥學會 2006 大韓藥學會 總會 및 學術大會 Vol.2006 No.1

인산화 처리 목분과 수피에 의한 중금속 흡착

백기현(Ki Hyon Paik),김동호(Dong Ho Kim),이동흡(Dong Heub Lee) 한국목재공학회 2000 목재공학 Vol.28 No.2

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활엽수로부터 D - xylose 의 분리 및 에탄올 생산

백기현 ( Paik Ki Hyon ) 한국목재공학회 1991 목재공학 Vol.19 No.2

제지약품의 개발동향 펄핑 및 표백제의 개발동향

백기현(Ki Hyon Paik) 한국공업화학회 2002 공업화학전망 Vol.5 No.3

N/A

용액의 처리조건에 따른 미처리 수피에 의한 중금속 흡착

백기현(Ki Hyon Paik),김동호(Dong Ho Kim),김승호(Seung Ho Kim) 한국목재공학회 2000 목재공학 Vol.28 No.2

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증기 전처리에 의한 낙엽송 심재의 방부제 처리도 개선에 관한 연구

백기현,김규혁,강승모 한국목재공학회 1997 목재공학 Vol.25 No.1

The effectiveness of presteaming for improving CCA treatability on refractory Japanese larch heartwood was investigated in this study. Presteaming was effective on improving treatability, and the extent of improvement was dependent. on moisture contents of wood specimen and steaming conditions. Green wood showed higher average value in both preservative retention and penetration than dry wood, and steaming under pressure conditions also had higher treatability than steaming at atmospheric conditions. The degree of improvement for treatability was increased with the extension of steaming period. Treatability of dry wood presteamed under pressure conditions more than 6 hours and green wood for 3 hours was similar to that can enhanced by conventional incising. Presteaming green wood under pressure conditions more than 6 hours was more effective than conventional incising in improvement of CCA treatability. and resultant treatability satisfied a minimum value required for CCA-treated wood for being used at the regions of hazard class H3 and H4. In addition. an improvement of treatability by presteaming was due to ar. increase in permeability resulted from the degradation of hemicelluloses within aspirated pit membrane and cell wall, not the removal of extractives from pit membrane. The reduction in strength. measured as longitudinal compressive strength, due to presteaming was related with the degradation of hemicelluloses, and was increased as steaming conditions were severe. The. degree of strength reduction associated with presteaming treatment to obtain required treatability could be quantified from the relatively good relation between the increase in treatability and the decrease in strength.

Organosolv 방법에 의한 활엽수 주요 조성분의 분리 및 이용

백기현,안병준,남원석 한국목재공학회 1988 목재공학 Vol.16 No.4

To separate and utilize the main components of hardwood (Quercus mongolica) by organasov pulping (ester pulping), chips were cooked at various conditions such as; the solvent ratio (acetic acid: ethylacetate: water, 50:25:25; 33:33:34; 25:50:25), maximum temperature (165, 170, 175℃), and cooking times (2, 2.5, 3 hr). The pulps were bleached by the sequences of CEDED, C/DEDED, PEDED. Lignin, sugars, and acetic acid were separated from black liquor and washing liquors. 1. The selective delignification at optimal pulp yield (43-45%) was obtained by cooking at acetic acid: ethylacetate: water ratio of 33:34:34 for 3 hr at 170℃. But in this case, kappa no. of the pulp was not reduced under 60 points. 2. Kappa no. of the pulp could be dropped by an acetone wash to remove reprecipitated lignin at cooked pulp. 3. The unbleached pulps had a brightness of 45-50%, whereas the bleached pulps gave at 88-93% brightness. Tensile, burst, and tear strengths of the bleached pulps were lower than those of kraft pulp, especially in tear strength. The pulps which were bleached with CEDED sequence were higher in strengths than another bleaching sequences. 4. Lignin of 90-95%(lignin base on wood)was separated from black liquor and washing liquors, while the purified sugars and recovery of acetic acid were a low. An organic phase composed of acetic acid, ethylacetate, and water was separated to a two-phase system by proper adjustment of the solvent ratios.