우리나라 하천 관리에서 생물지형학의 적용과 전망

김대현(Daehyun Kim),김원(Won Kim),김은석(Eunsuk Kim),옥기영(Giyoung Ock),장창래(Chang-Lae Jang),최미경(Mikyoung Choi),조강현(Kang-Hyun Cho) 응용생태공학회 2020 Ecology and resilient infrastructure Vol.7 No.1

하천과 홍수터 생태계에서 생물지형학 연구는 폭 넓은 시공간 차원에서 생물계와 수문-지형체계 사이의 복잡한 다중관계를 다루어 왔다. 본 총설에서는 하천에서 (1) 생물과 수문지형 조건의 다자간 관계, (2) 생물다양성과 서식처 이질성의 관계, (3) 생태계 유형에 대한 교란의 영향에 대하여 설명함으로써 하천지형생물학의 범위와 과정을 논의하였다. 시간적으로 하천의 생물지형 복합체는 지형, 선구, 생물지형 및 생태적 단계의 순서로 전환이 된다. 공간적으로 물 흐름과 유사 분포가 식생과 상호작용하여 하도 지형의 변화가 일어난다. 이렇게 형성된 하천의 공간적 이질성은 하안의 생물종다양성을 증가시킨다. 그러나 댐 하류 하천에서는 서식처 유형과 조건이 심각하게 훼손되어 생물다양성이 저하된다. 우리나라의 하천에서는 최근 국지적 교란과 전 지구적 기후변화로 하안 식생이 번무하고 특히 외래종이 빠르게 정착하고 있다. 따라서 급격한 기후변화와 인류에 의한 압박의 시대에서 하천 생물과 수문지형 조건 사이의 상호 관계를 이해하는 것이 더욱 중요할 것으로 생각된다. 이 총설에서 논의한 하천 생물지형 개념틀은 우리나라 하천의 생태적 관리와 복원에 기여할 것으로 기대된다. In fluvial and riparian ecosystems, biogeomorphological research has considered the complex, multi-way relationships between biological and hydro-geomorphological components over a wide range of spatial and temporal scales. In this review, we discussed the scope and processes of fluvial biogeomorphology by explaining (1) the multi-lateral interactions between organisms and hydrogeomorphic conditions, (2) the relationships between biodiversity and habitat heterogeneity, and (3) the effects of disturbance on ecosystem patterns. Over time, an organism-landform complex along streams transitions in the sequences of geomorphic, pioneer, biogeomorphic, and ecological stages. Over space, water flow and sediment distributions interact with vegetation to modify channel topography. It is the habitat heterogeneity in streams that enhances riparian biodiversity. However, in the areas downstream of a dam, habitat types and conditions are substantially damaged and biodiversity should be reduced. In South Korea, riparian vegetation flourishes in general and, in particular, invasive species actively colonize in accordance with the changes in the fluvial conditions driven by local disturbances and global climate change. Therefore, the importance of understanding reciprocal relationships between living organisms and hydrogeomorphic conditions will ever increase in this era of rapid climate change and anthropogenic pressure. The fluvial biogeomorphic framework reviewed in this article will contribute to the ecological management and restoration of streams in Korea.

Bi-Mo系 複合化合物의 生成 및 浸出機構에 關한硏究

陸承柱,李相和,崔昌鈺,黃龍吉 동아대학교 공과대학 부설 한국자원개발연구소 1982 硏究報告 Vol.6 No.2

This study is to find out the complex compounds formed when bismuth oxide(Bi₂O₃) and molybdenum trioxide (MoO₃) are mixed at theoretical mole ratios and the condition of the selective reduction of the complex compounds reacted at various temperatures with the active carbon as a reducing element. The results obtained from the alkali leaching conducted under the condition of selective reduction are summarized as follows; 1. The reaction products obtained by mixing Bi₂O₃ and MoO₃ with a mole ratio of 2 to 1 and heating the mixture at 500℃ have found to be Bi₂MoO_(6), Bi₄MoO_(6) and α-Bi₂O₃ whereas at the temperature between 670℃ and 950℃ the main product has been identified to be Bi₄MoO_(9) according to the following reaction: Bi₂O_(6)+α-Bi₂O₃→Bi₄MoO_(9) 2. When the complex compound Bi₄MoO_(9) is reduced for alkali leaching, the optimum amount of carbon and the optimum temperature have been shown to be 4 moles and 800℃, respectively, due to the fact that the maximum reduction rate can be obtained under these optimum conditions. 3. The previous experimental result showed that the alkali leaching ratio of Bi₄MoO_(9) was decreased under atmospheric pressure. However, the alkali leaching of MoO₃ has been found to occur due to the selective reduction of Bi that takes place with more than 4 moles of carbon used as a reducing element at a temperature be tween 600℃ and 900℃ by the following reactions: Bi₄MoO_(9)+6C→4Bi+MoO₃+6CO 2Bi₄MoO_(9)+7C→8Bi+2MoO₂+7CO₂ 4. The comparison analysis for the leaching effect of NaoH and Na₂CO₃ has shown that in the case of using over 4 moles of carbon as a reducing element the leaching rate of NaOH is much higher than that of Na₂CO₃.

燒結鐵의 硬度 및 組織에 미치는 密度의 영향에 관한 硏究

李興植,李相和,崔昌鈺 동아대학교 공과대학 부설 한국자원개발연구소 1983 硏究報告 Vol.7 No.2

This study has been investigated into the change of hardness and microstrure as a function of density for ferrous sintered alloys. The specimens were prepared from Sweden Ho¨gana¨s atomized iron powder(ASC 100.29) and partially prealloyed powder (Distaloy AB) with 1.75% Ni, 1.5% Cu, and 0.3% Mo based on the same iron powder which is typically used in P/M parts production was blended with 0.2% grephite powder, and then compacted, sintered and carburized. The results obtained from the experiment are summarized as follows; 1. The green density increased with the increase of compacting pressure, and the compressibility decreased with adding alloy composition. 2. The true hardness was higher than the apparent hardness in the ferrous sintered metals. And the difference between apparent and true hardness values decreased with decreasing porosity or adding 3. The difference between the apparent hardness values of different sections was reduced with decreasing porosity, adding alloy composition or being longer carburization times. 4. The apparent hardness values after gas carburizing treatment were highly dependent upon the density and carburization depth. 5. After gas carburizing treatment the hardness values both on the surface and in the core were increased as the porosity decrease. In a certain intermediation zone, however the hardness values of the low density was higher than those of the high density. 6. The average grain size was larger with decreasing porosity, and the homogeneous microstructure could be obtained with decreasing porosity.

조석환경 변화에 의한 표층퇴적물의 시.공간적 분포 변화: 한국 서해안의 무안만

류상옥,장진호,이희준,조영조,최옥인,Ryu, Sang-Ock,Chang, Jin-Ho,Lee, Hee-Jun,Jo, Yeong-Jo,Choi, Ok-In 한국해양학회 2009 바다 Vol.14 No.1

하구언과 방조제 건설에 따라 고극조위 상승과 같은 조석환경 변화가 심한 무안만에서 표층퇴적물의 분포 변화와 변화 원인을 규명하기 위하여 퇴적물 시료를 채취하고 조류관측을 실시하였다. 무안만의 표층퇴적물은 1998년에 비해 역과 사의 조립질퇴적물의 함량이 증가하고 실트의 함량이 감소하여 퇴적물의 평균입도는 6.2${\phi}$에서 5.8${\phi}$로 조립해지는 경향을 보였다. 조립질퇴적물의 함량 증가와 실트의 함량 감소는 만조선 주변을 중심으로 광범위하게 나타났으며, 특히 동암리와 구로리, 압해도 조간대에서 두드러지게 나타났다. 만조선 주변의 조립화 현상은 일차적으로 하구언 및 방조제 건설에 따른 고극조위 상승에 기인하는 것으로 해석된다. 한편, 서측 만입구 주변에서 세립질퇴적물의 함량이 증가하는 현상은 인공구조물(교각) 건설에 따른 조류속의 감소와 위상차에 의한 조류의 방향 변화 등 수류의 변형에 기인하는 것으로 판단된다. Muan Bay has extensively undertaken artificial influences through a series of construction of dams and dykes nearby resulting in a substantial increase in highest high water level. To unravel sedimentary responses to the water level rise, we collected a number of surface sediment samples and hydrodynamic data from in-situ observations of tidal currents in Muan Bay in 1998 and 2007. Comparison of the data between 1998 and 2007 shows that the relative content of coarse fractions, sand and gravel, in the sediment samples has increased with a decreased mean size, on average, from 6.2 to 5.8${\phi}$ at the expense of silt contents. Such a coarsening trend, which is more evident around high water level, particularly on the tidal flats of Dongam-ri, Guro-ri and Aphae-do, is most likely attributable to rising water level. On the other hand, an increase of fine fractions locally in the western entrance of the bay can be explained with changes in characteristics of tidal currents imposed by construction of bridges therein, such as decreased velocities and varied direction and phase of the tidal currents.

폐경 여성에서 에스트로겐-프로게스토겐 치료 후 전혈세포에서의 Osteoproteoerin (OPG), Soluble Receptor Activator for Nuclear Factor κB Ligand (sRANKL) 생산의 변화와 골밀도 변화 사이의 관계

이동옥 ( Dong Ock Lee ),김훈 ( Hoon Kim ),채수진 ( Soo Jin Chae ),서창석 ( Chang Suk Suh ),김석현 ( Seok Hyun Kim ),최영민 ( Young Min Choi ),문신용 ( Shin Yong Moon ),김정구 ( Jung Gu Kim ) 대한폐경학회 2007 대한폐경학회지 Vol.13 No.2

연구목적: 폐경 여성에서 호르몬 치료 후 전혈세포에서의 OPG, sRANKL 생산의 변화과 골밀도 변화사이의 연관성을 알아보고자 하였다. 연구재료 및 방법: 폐경여성 224명에서 LPS로 자극한 전혈세포에서 OPG, sRANKL 생산, 혈청 OST, CTX, PTH, 칼슘, 인 농도를 측정하였다. 또한 요추와 근위부 대퇴골의 골밀도를 측정하였다. 이중 주기적 에스트로겐-프로제스토젠 치료가 118명에서 시행되었다. 결과: 전혈세포에서 OPG 생산은 연령과 양성 상관관계가 있었고 저골량을 가진 여성에서 정상 여성보다 유의하게 증가하였다. 반면 sRANKL 생산과 sRANKL/OPG 비는 연령과 음성 상관 관계를 보였고 골밀도 상태에 따른 차이를 보이지 않았다. 전혈세포에서의 OPG와, sRANKL 생산 및 그 비는 혈청 OST, CTX, PTH 칼슘, 인와 상관관계가 없었다. 호르몬 치료 6개월 후 전혈세포에서의 OPG 생산은 유의하게 증가하였으나 sRANKL 생산과 sRANKL/OPG 비는 변화하지 않았다. 호르몬 치료 1년후 대퇴골경부 에서의 골밀도 변화는 호르몬 치료 전 전혈세포에서의 OPG와 sRANKL 생산과 음성 상관관계가 있었으나 sRANKL/OPG 비는 양성 상관관계를 보였다. 호르몬 치료 6개월후 전혈세포에서의 OPG와 sRANKL 생산 변화는 호르몬치료 1년후 골밀도의 변화와 상관관계가 없었다. 결론: 호르몬 치료 후 전혈세포에서의 OPG, sRANKL 생산 및 그 비의 변화는 골밀도 변화와 관련이 없으나 치료전 전혈세포에서 OPG, sRANKL 생산은 호르몬치료 1년후 대퇴골경부에서의 골밀도의 변화을 반영할 수 있다. Objectives: To investigate the relationship between changes in the production of osteoprotegerin (OPG), and soluble receptor activator for nuclear factor κB lignad (sRANKL) by whole blood cells (WBCs) and changes in bone mineral density (BMD) after hormone therapy (HT) in postmenopausal women. Methods: The production of OPG, and sRANKL by lipopolysaccharide-stimulated WBCs blood cells, serum levels of osteocalcin (OST), type I C-telopeptide breakdown products (Crosslaps; CTX), parathyroid hormone (PTH), calcium, and phosphorus were measured in 224 postmenopausal Korean women. The BMD at lumbar spine and proximal femur was also determined. One hundred and eighteen postmenopausal women took sequential estrogen-progestogen therapy. Results: The production of OPG by WBCs correlated positively with age and was significantly higher in women with low bone mass than in normal women. The production of sRANKL and sRANKL/OPG correlated negatively with age and was not different according to state of BMD. These OPG and RANKL productions did not show any relationship with serum levels of OST, CTX, PTH, calcium, and phosphorus. After 6 months of HT, the production of OPG by WBCs increased significantly, but no change in the production of sRANKL, and sRANKL/OPG ratio was noted. The 1-year change in BMD of femoral neck correlated negatively with the basal production of OPG by WBCs and positively with basal sRANKL/OPG ratio. Changes in the production of OPG and sRANKL after 6 months of HT were not associated with the 1-year change in BMD. Conclusion: After HT, changes in the production of OPG, and sRANKL by WBCs did not correlate with changes of BMD, but basal production of OPG by WBCs and sRANKL/OPG ratio correlated with changes in BMD of femoral neck after HT.

L.D. 전로슬랙을 (轉爐) 이용한 규산소오다계 자경성주형의 (自硬性鑄型) 일반성질

최창옥 ( Chang Ock Choi ) 한국주조공학회 1981 한국주조공학회지 Vol.1 No.1

N/A Investigations have been carried out to develop self-hardening sand mold using sodium silicate binder and L.D. converter slag hardener. On weight basis, the amount of sand-mix were varied 100 % sand, from 4%, to 9% binder and from 2% to 5% hardener. For laboratory investigations, standard sand samples were prepared and tested for compressive strength, S.S.I., bench time, retained moisture and retained compressive strength, The results obtained indicate a distinct possibility of using L. D. converter slag hardener in the self-hardening molding process with sodium silicate, It was observed that the composition of L. D. converter slag has β-C₂S and about 2 degree of basicity, compressive strength and surface stability increase and retained compressive strength, retained moisture, and bench time decrease with increase in the percentage of hardener in relation to binder.

기술강좌(技術講座) : 주물공장 발생폐기물의 처리 및 재활용기술 동향

최창옥 ( Chang Ock Choi ),길상철 ( San Cheol Kil ) 한국주조공학회 2010 한국주조공학회지 Vol.30 No.1

기술강좌(技術講座) : 구환경부하에서 구상흑연주철품의 청정생산기술 개발 동향

최창옥 ( Chang Ock Choi ),길상철 ( Sang Cheol Kil ) 한국주조공학회 2011 한국주조공학회지 Vol.31 No.4

한국 전통 금속 공업 : 주물솥

최창옥 (Chang Ock Choi) 대한금속학회 1999 大韓金屬學會會報 Vol.12 No.1

취임사

최창옥 ( Chang Ock Choi ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.1