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슈미트해머 반발도와 OSL 연대에 기반한 둔두리 해식애의 형성과정
최광희 ( Kwang Hee Choi ),성영배 ( Yeong Bae Seong ),최정헌 ( Jeong Heon Choi ),정필모 ( Pil Mo Jung ),이수용 ( Soo Yong Lee ) 한국지형학회 2013 한국지형학회지 Vol.20 No.1
충남 둔두리 해안에 분포하는 해식애에 대하여 슈미트해머 반발도를 측정하고, 해식애 피복층에 대해 OSL 연대를 측정하였다. 이 해식애의 평균반발도는 인접한 파식대에 비해 평균적으로 작았지만, 지점에 따른 편차가 크게 나타났다. 또한 후퇴거리가 증가할수록 반발도가 감소하였다. 암질의 차이 때문에 약한 부분이 강한 곳보다 빠르게 후퇴하며 해식애 표면이 불규칙하게 발달한 것으로 추정된다. 해식애를 덮고 있는 피복층은 원마도가 낮은 역과 실트로 구성되어 있고 분급이 불량하였으며 계곡부의 퇴적층후가 상대적으로 두껍게 나타났다. 여기서 채취한 세립퇴적물의 OSL 연대(약 70∼77ka)는 기존연구에서 우주선유발동위원소를 이용한 해식애 노출연대(약 7∼30ka)보다 오래된 것으로 나타났다. 따라서 둔두리 해식애는 지난 간빙기 이후 사면퇴적물에 의해 피복되었던 파식대가 홀로세 동안 피복층이 제거되면서 확장되는 과정에서 발달한 것으로 추정된다. Rock strength test on Dunduri cliff, Chungnam province, Korea, was performed using N-type Schmidt hammer and the depositional ages of the sediments overlying the cliff were derived using OSL dating method. The averaged R-values of the cliffs investigated here were lower than those observed from the shore platforms, but with larger scatter in the former. R-values were negatively correlated to cliff face retreat, implying that the irregularity of the coastal rock faces was closely related to lithology as the weaker rocks retreated much faster than the harder rocks. The overlying deposit of the cliff tends to be thicker at valleys and were poorly sorted with angular to subangular clasts in a matrix of silt. The OSL ages (ca. 70-77ka) presented here were older than the previously reported exposure ages (ca. 7-30ka) of the cliff face. Therefore, it is likely that the present sea cliff was developed by expansion of the platform which had been covered by slope deposits since the last interglacial and exposed again during the Holocene.
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효과적인 유역관리를 위한 CN기법 기반의 침투량 산정 및 기저유출량 분석
김희원 ( Hee Won Kim ),신연주 ( Yeon Ju Sin ),최정헌 ( Jung Heon Choi ),강현우 ( Hyun Woo Kang ),류지철 ( Ji Chul Ryu ),임경재 ( Kyoung Jae Lim ) 한국물환경학회 2011 한국물환경학회지 Vol.27 No.4
Increased Non-permeable areas which have resulted from civilization reduce the volume of groundwater infiltration that is one of the important factors causing water shortage during a dry season. Thus, seeking the efficient method to analyze the volume of groundwater in accurate should be needed to solve water shortage problems. In this study, two different watersheds were selected and precipitation, soil group, and land use were surveyed in a particular year in order to figure out the accuracy of estimated infiltration recharge ratio compared to Web-based Hydrograph Analysis Tool (WHAT), The volume of groundwater was estimated considering Antecedent soil Moisture Condition (AMC) and Curve Number (CN) using Long Term Hydrologic Impact Assessment (L-TH1A) model. The results of this study showed that in the case of Kyoung-an watershed, the volume of both infiltration and baseflow seperated from WHAT was 46.99% in 2006 and 33.68% in 2007 each and in Do-am watershed the volume of both infiltration and baseflow was 33.48% in 2004 and 23.65% in 2005 respectively. L-TFIIA requires only simple data (i.e., land uses, soils, and precipitation) to simulate the accurate volume of groundwater. Therefore, with convenient way of L-TKIA, researchers can manage watershed more effectively than doing it with other models. L-THIA has limitations that it neglects the contributions of snowfall to precipitation. So, to estimate more accurate assessment of the long term hydrological impacts including groundwater with L-THIA, further researches about snowfall data in winter should be considered.
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再生펄프를 利用한 카르복시메틸셀룰로오스의 製造(Ⅱ) : CMC의 物性 測定 Physical Charateristic of CMC
崔正憲,趙炳默,吳正壽 동국대학교 생명자원과학대학 연습림 1993 연습림논문집 Vol.- No.3
Carboxymethylation of recycled pulp was investigated. For both recycled pulp and dissolving pulp was carboxymethylated by the organic solvent method and tested some industrial analyses, water solubles content, low concentration of NaCl solution solubles and acid hydrolysis. The water solubles content depend on degree of substitution, and low concentration of NaCl did not affected solubilities of the CMC. Prehydrolysis of CM groups prior to reaction with Lcystein, we can obtain the residual unsubstitued anhydroglucose(USAG). The lower amount of USAG in recycled pulp, compared to theorecal data, was suggested that the recycled pulp should obtain the more CM group in the same conditions.
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오정수,조병묵,최정헌 한국목재공학회 1995 목재공학 Vol.23 No.2
The substitution of carboxymethylated hydroxyl group in pulp revealed mere hydrophilic than hydroxyl group. And then fibers were more flexible, swell more which leads to better conformation between fibers in turn this raise paper strength. In this paper, we tried to chemical modifyings of recycled fiber, OCCs(old corrugated containers). Many researchers have examined chemical modification of papermaking fiber by partial carboxymethylation (PCM) using a organic solvent processes. We made modified PCM processes adapted waters in replace of the organic solvent. Our testings for the optimum conditions on the new method, conditions as reaction tune, temperature, liquor ratios were designed likely plant system. Freenesses(SR°) were increased following on carboxyl content of the samples. Handsheets of untreated samples and partial carboxymethylated OCCs were made by optimum conditions on different concentrations of the reagent. As results, maximum 25% strength increasing effects were obtained by the new method.
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오정수,조병묵,최정헌 한국목재공학회 1993 목재공학 Vol.21 No.1
The purpose of this study is to investigate the preparation of the carboxymethycellulose from recycled fiber, especially on the reactivity of carboxymethylation. Using a deinked pulp and a dissolving pulp, Green's method is adapted to the carboxymethylation. We conformed that the carboxymethyl group is led for recycled fiber by FT-IR analysis. The recycled fiber is more reactive than the dissolving pulp because the recycled fiber had been defiberated and pretreated with alkali. It suggests that deinking process is in accordance with pretreatment of CMC process. Therefore, it may be possible to prepare CMC from the recycled fiber economically.
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