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      • KCI등재

        만경강 유역내 하천의 특성별 영향 평가

        윤순강,이종식,정구복,김민경,김선종,고문환,엄기철 한국환경농학회 2002 한국환경농학회지 Vol.21 No.4

        본 연구는 만경강 유역의 수질 보전을 위한 기초자료를 얻기 위하여 만경강 본류와 이에 유입되는 지천을 선정하여 2001년 5월부터 11월까지 매월 수질 모니터링을 실시하였다. 만경강 유역내 본류 및 지천의 유기물과 영양염류 함량을 조사한 결과, 본류의 T-N은 3.78~12.68 ㎎/L였으며, 지천중 축산폐수가 유입되는 익산천의 농도가 가장 높았다. 본류의 T-P의 BOD는 각각 0.043~0.864 ㎎/L와 2.59~13.29 ㎎/L였으며, 지천중 익산천이 가장 높았다. 본류의 COD는 12.9~119.5 mg/L였으며, 지천중 도시생활하수가 유입되는 추천이 가장 높았다. 만경강 유역 수질저하의 주 원인은 축산폐수였으며, 도시생활하수가 그 다음으로 중요한 원인으로 평가되었다. 만경강 본류의 T-N과 T-P는 하천의 유량이 증가하는 홍수기인 7~8월보다 장마선 갈수기인 5~6월에 높았고, COD는 장마전 갈수기보다 홍수기에 높았으며 장마가 완전히 끝난 영농후 갈수기인 9~11월에도 수질저하가 지속되었다. 만경강에 유입되는 지천중 전반적으로 수질오염이 심각한 익산천과 추천은 영농후 갈수기에 수질이 가장 저하되었고 상대적으로 홍수기에는 양호하였다. A survey on four tributaries along with Mankyeong River was carried out to get the information for the water quality improvement and control. Typical paddy farming were major agricultural practices in Kosancheon and Soyangcheon. Iksancheon was livestock raising watershed. Chucheon was urban watershed. Water quality in six sites of main stream and four sites of tributaries in Mankyeong River were investigated from May to August in 2001. The concentration of nutrients in main stream of Mankyeong River were in the range of 3.78~12.68 mg/L for total nitrogen, 0.043~0.864 mg/L for total phosphorus, 2.59~13.29 mg/L for BOD and 12.9~119.5 mg/L for COD, respectively. Water quality of Mankyeong River mostly exceeded the standard water quality criteria of Korea. Major causes of water pollution were evaluated as sewage of swine and urban area. Among the four tributaries, water quality in agricultural practices, Kosancheon and Soyangcheon was relatively less polluted. While, the highest level of water pollution measured in Iksancheon was due to livestock The water quality of Iksancheon and Chucheon was generally more polluted in the dry period than in rainy period.

      • KCI등재
      • 폐경기 여성에서의 Cyclofenil의 효능에 관한 연구 : 갱년기 장애 및 Ca 장흡수에 관하여

        노흥규,윤상임,성기양,이경숙,이강욱 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.1

        In postmenopausal syndrome, most common symptoms are those of vasomotor irritability such as hot flush and palpitation, irritable bladder symptoms and dyspareunia according to atrophy of urogenital epithelium, anxiety, nervousness, depression and insomnia. Approximately 40 percent of women in postmenopausal period develop symptoms serious enough to seek medical assistance. Among non-steroid agents, cyclofenil(4, 4' cyclohexidene methlyene diphenoacetate) is known to be a quite interesting substance according to the action at the level of the hypophyseal and hypothalamic centers by reducing the incretion of FSH and restoring normal endorphin, dopamine and norepinephrine activities, thus favorably affecting the whole postmenpausal neurovegutative symptomatology. In order to evaluate effect of cyclofenil on postmenopausal symptomatology and calcium metabolism, we examined 32 patients with postmenopausal syndrome before and after 200mg/day of oral cyclofenil treatment for 30-60 days. The results were as follows: 1. With 30 days of cyclofenil administration, subjective symptoms such as facial flush, palpitation, anxiety, nervousness and dyspareunia were improved significantly (p<0.001, p<0.001, p<0.01, p<0.005, respectively). But insomnia and depression were improved significantly after 60 days of cyclofenil administration (p<0.05, p<0.001, respectively). 2. Intestinal calcium absorption rate disclosed tendency of improvement without statistical significance 30 days after cyclofenil treatment. 3. Serum calcium and phosphorus level were not changed significantly before and after cyclofenil. 4. There was no definite evidence of side effects such as uterine bleeding due to cyclofenil. In conclusion, we thought that cycofenil is effective in management of postmenopausal syndrome but for the effect on calcium metabolism, further evaluation should be needed.

      • SCOPUSKCI등재

        Carbonation of Circulating Fluidized Bed Combustion Fly Ash with Hybrid Reaction

        Lee, Ki Gang,Bae, Soon Jong The Korean Ceramic Society 2018 한국세라믹학회지 Vol.55 No.2

        This paper investigates the reaction rate of $CO_2$ storing carbonation hybrid reaction by comparing the behavior of carbonation between $Ca(OH)_2$ and fly ash with that of CFBC (Circulating Fluidized Bed Combustion) containing plenty of Free-CaO. Because fly ash with CFBC contains a lot of unreacted CaO, it cannot be used as a raw material for concrete admixtures and its usages are limited. To reuse such material, we stabilized unreacted CaO by carbonation and investigated the carbonation rate. We used a pH meter and a thermometer to check the rate of the carbonization. Also, we set the contents of fly ash with CFBC, $Ca(OH)_2$, flow and fluid of $CO_2$, respectively, to 100 g, 50 g, 100 ~ 1000 cc/min and 400 g based on the content of Free-CaO. We used carbonated water instead of water, and added an alkaline activator to promote the carbonation rate. As a result, the addition of the alkaline activator and carbonated water promoted the rate of carbonation via a hybrid reaction.

      • SCOPUSKCI등재

        Bloating Mechanism for Artificial Light Weight Aggregate of Surface Modification with Coal ash

        Lee, Ki Gang The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.2

        We manufacture artificial lightweight aggregates (ALWAs) using bottom-ash as the primary raw material. We coat the ALWA surfaces with low-melting point materials in order to enable them to bloat, which is essential to reduce the bulk density of the aggregate. Then, we sinter the prepared aggregates at 1000, 1100, and $1200^{\circ}C$ using either the direct or two-step firing schedules. Finally, we evaluate the properties of the fired samples through analyzing their bulk density, water absorption, and microstructure. The surface-modified samples result in a reduction of their bulk density by $0.3{\sim}0.4g/cm^3$ regardless of the firing method used. Based on these results, we conclude that this approach could provide a viable method for the mass-production of ALWAs from industrial waste such as bottom-ash.

      • KCI등재

        Highly Porous Three-dimensional Poly(lactide-co-glycolide) (PLGA) Microfibrous Scaffold Prepared by Electrospinning Method: a Comparison Study with Other PLGA Type Scaffolds on Its Biological Evaluation

        Gang, Eun Hee,Ki, Chang Seok,Kim, Jong Wook,Lee, Jonghwan,Cha, Bum Gyu,Lee, Ki Hoon,Park, Young Hwan 한국섬유공학회 2012 FIBERS AND POLYMERS Vol.13 No.6

        In this study, a three-dimensional (3D) poly(lactide-co-glycolide) (PLGA) microfibrous scaffold with high porosity (ca. 90 % porosity) was developed for evaluating its performance in tissue engineering application. A dope solution of PLGA/polyethylene oxide (PEO) blend was electrospun into a methanol coagulation bath for fabricating highly porous 3D PLGA scaffold and a salt leaching method was used for making interconnected pores of 100-200 ${\mu}m$ size inside the scaffold. The morphological structure, pore size and porosity of the microfibrous scaffold were determined, and compared with two-dimensional (2D) mat-type and 3D sponge-type of PLGA scaffold. Also, swelling ratio, water uptake and compressive strength were compared in order to elucidate the structure-property relationships of different types of the scaffolds, especially in a wet condition. As a result of scanning electron microscopy (SEM) observation, normal human dermal fibroblasts (nHDF) were migrated, attached, and proliferated well inside the 3D scaffold. MTT assay confirmed that the highly porous 3D PLGA microfibrous scaffold had superior cell adhesion and proliferation abilities due to fibrous structure of large specific surface area, and interconnected pore structure. Therefore, this high performance 3D PLGA scaffold can have a high potentiality for application in tissue engineering in comparison with conventional PLGA scaffolds.

      • SCOPUSKCI등재

        Bloating Mechanism of Lightweight Aggregate with the Size

        Lee, Ki Gang The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.2

        The purpose of this study was to investigate the bloating mechanism of artificial lightweight aggregates with different sizes (ESA, effective surface area). Aggregates were produced using hard clay, stone sludge, and a bloating agent in order to observe the effect of the gradation of the artificial lightweight aggregates. Kerosene and amorphous carbon were used as bloating agent. The particle size of the produced aggregate ranged from 3 mm to 9 mm. With regard to the amount of bloating agent to be used, 2 ~ 6 parts by weight were used. The specific gravity, absorption rate, and the type of aggregates produced by rapid sintering at $1075{\sim}1200^{\circ}C$ were determined. Microstructures were observed. When ESA had a value of 1 or below, kerosene, which has a high burning rate, was found to be advantageous for use as a bloating agent. When ESA had a value of 1 or above, carbon, which has a relatively low burning rate was found to be an advantageous bloating agent. It is thought that kerosene is more advantageous, as ESA decreases, for the production of aggregates having low water absorption rate.

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