• 한국환경보건학회지
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• 제26권4호
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• pp.65-74
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• 2000

The sensitivity of a mehtanogen and sulfate-reducing bacterium isolated from a sea-based landfill site Cd$^{2+}$ and CU$^{2+}$ was studied. Methanogens and sulfate-reducing bacteria in leachates of the waste disposal site were enumerated using the MPN method. Methanobacterium thermoautotrophicum KHT, isolated from the leachate, could not grow at 0.5 mM Cd$^{2+}$ or 1.0 mM CU$^{2+}$. Desulfotomaculum sp. RHT, isolated from the same leachate, was able to insolubilization 3.0 mM Cd$^{2+}$ or 2.0 mM CU$^{2+}$ by production of hydrogen sulfide. When strains KHT and RHT were cultured together in the presence of the heavy metals, strain KHT could grow at high heavy metal concentrations after insolubilization of the metals by strain RHT. strain RHT.

• 자원환경지질
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• 제5권4호
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• pp.211-217
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• 1972

The Second Yeon Hwa Mine which belongs to a so called Lead-Zines Belt Area in the central east Korea is located at about 10 km northeast of the Seogpo railway station on Yeongdong Line. The exploitation of the mine started in June, 1969 and furnished the machinary ore dressing plant in November, 1971. The current monthly production of rude ore is 15,000 meteric tons. The results of the study on the lead-zinc-copper deposits of the Second Yeonhwa mine are summerized as follows: (1) main ore deposits of the mine are localized in the Pungchon Limestion formation of Cambrian age, (2) related ingneous rock with ore deposits is granite porphyry, which distributed in NS and $N50^{\circ}W$ trend, (3) ore solution ascended along the $N50^{\circ}W$ trend which represents folding axis and fault plane and mineralized selectively in the limestone formation. (4) high grade ore deposits are localized in concave and convex boundaries of granite porphyry, and hanging walls of shale bed ($P_2S$ shale bed) in Pungchon Limestone formation and (5) skarn minerals are consisted of garnet, hedenbergite, diopside, and sulfide minerals are composed of zincblenede, galena, phyrhotite, pyrite and some amount of chalcopyrite and arsenopyrite.

• 한국축산시설환경학회지
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• 제7권1호
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• pp.29-32
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• 2001

In this experiment porous calcium silicate (PCS) powder prepared by using a 50 mesh sieve was spread on top of chick droppings to investigate the odor from the manure. Zeolite was used as a comparative purpose. Reduction in ammonia production from chick droppings shortly after the PCS and zeolite application was evident (P<0.05), but there were no difference among treatments afterwards. hydrogen sulfide level was significantly lowered by both PCS and zeolite treatment(P<0.05).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.93-94
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• 2023

Through the industrial revolution that began in the 18th century, the amount of carbon dioxide in the atmosphere increased rapidly as humans used fossil energy such as coal and oil as fuel for steam engines and factory machines. The amount of carbon dioxide emitted while producing cement, the main material of concrete used in construction, is large enough to account for 5-8% of the world's carbon dioxide emissions. In this study, Non cement-based matrix were used to reduce carbon dioxide emissions from cement production. Red mud is an industrial by-product generated in the manufacturing process of aluminum hydroxide using bauxite, and more than 120 million tons are produced worldwide. In addition, red mud is a porous material that can be physically adsorbed, and causes a photocatalytic reaction of TiO₂ to remove harmful substances such as nitrogen oxide formaldehyde in the air and chemically adsorbs ammonia and hydrogen sulfide. Therefore, this study aims to examine the physical properties of the matrix by mixing red mud, an industrial by-product with good adsorption performance, into the Non cement-based matrix.

• Asian-Australasian Journal of Animal Sciences
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• 제26권2호
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• pp.266-274
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• 2013

The effect of different phytogenic feed additives on reducing odorous compounds in swine was investigated using in vitro fermentation and analyzed their microbial communities. Soybean meal (1%) added with 0.1% different phytogenic feed additives (FA) were in vitro fermented using swine fecal slurries and anaerobically incubated for 12 and 24 h. The phytogenic FAs used were red ginseng barn powder (Panax ginseng C. A. Meyer, FA1), persimmon leaf powder (Diospyros virginiana L., FA2), ginkgo leaf powder (Ginkgo biloba L., FA3), and oregano lippia seed oil extract (Lippia graveolens Kunth, OL, FA4). Total gas production, pH, ammonianitrogen ($NH_3$-N), hydrogen sulfide ($H_2S$), nitrite-nitrogen ($NO_2{^-}$-N), nitrate-nitrogen ($NO_3{^-}$-N), sulfate (${SO_4}^{--}$), volatile fatty acids (VFA) and other metabolites concentration were determined. Microbial communities were also analyzed using 16S rRNA DGGE. Results showed that the pH values on all treatments increased as incubation time became longer except for FA4 where it decreased. Moreover, FA4 incubated for 12 and 24 h was not detected in $NH_3$-N and $H_2S$. Addition of FAs decreased (p<0.05) propionate production but increased (p<0.05) the total VFA production. Ten 16S rRNA DGGE bands were identified which ranged from 96 to 100% identity which were mostly isolated from the intestine. Similarity index showed three clearly different clusters: I (FA2 and FA3), II (Con and FA1), and III (FA4). Dominant bands which were identified closest to Eubacterium limosum (ATCC 8486T), Uncultured bacterium clone PF6641 and Streptococcus lutetiensis (CIP 106849T) were present only in the FA4 treatment group and were not found in other groups. FA4 had a different bacterial diversity compared to control and other treatments and thus explains having lowest odorous compounds. Addition of FA4 to an enriched protein feed source for growing swine may effectively reduce odorous compounds which are typically associated with swine production.

• 한국자동차공학회논문집
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• 제25권1호
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• pp.35-41
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• 2017

The use of engineering plastics in automotive components is increasing with the trend towards improving the car strength and reducing weight. Among the different choices of materials, engineering plastic emerged as the necessary material for achieving lower costs, reduced weight and improved production efficiency. To produce the automotive parts, it is important to predict defect and validation of injection molding prior to design. Injection molding analysis and structural analysis are widely applied as a part of the design process when developing automotive parts. Injection molding analysis, in particular, involves a highly complicated mechanism that requires deep knowledge of polymer properties as well as an analytic approach different from that used for a general isotropic material when the molded material is used as a structural material. This is because the parts made of polymer have pre-stress factors such as intrinsic deformation and residual stress. The most important factors for injection molded plastic products are injection molding condition and cavity design, taking into account ease of molding, mass production and application. Despite optimal injection molding conditions and cavity design, however, glass fiber orientation is critically linked to strength reduction. The application of injection molding and structural coupled analysis provides a low-cost solution for product molding and structural validation, all prior to the actual molding. The purpose of this study involves the validation, pre-study, and solution of defect in injection-molded polymer automotive parts using the simulation software for injection molding and structural coupled analysis. Finally, this thesis provides validation of an injection molding and structural coupled analytic mechanism that can demonstrate the effect of glass fiber orientation on mechanical strength. Design improvement ideas for the injection molded product of PPS (Poly Phenylene Sulfide)+40% glass fiber are also suggested.

• 자원리싸이클링
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• 제30권5호
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• pp.49-56
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• 2021

본 연구에서는 Black Ash법을 이용하여 홍천 자철광으로부터 회수된 황산스트론튬 (SrSO₄)으로부터 탄산스트론튬 (SrCO₃)을 제조하였다. Carbothermic 반응 단계에서는 황화스트론튬 (SrS)을 제조하기 위해 1273 K의 Ar 가스 분위기의 석영반응기를 사용하여 SrSO₄를 탄소와 같이 반응시켰다. 이후 353 K에서 carbothermic 반응으로 회수된 잔사의 수침출 및 298 K에서 탄산나트륨 (Na₂CO₃)를 이용한 침출액의 탄산화 반응을 통해 SrCO₃을 제조하였다. 본 연구결과로부터 Black Ash법 활용 시 국내산 자철광 내 함유된 스트론튬 (Sr)으로 부터 고순도 탄산스트론튬 제조가 가능함을 실험적으로 증명하였다.

• 보존과학회지
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• 제38권1호
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• pp.45-54
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• 2022

This study examined the production technique of bracket murals in Daeungjeon Hall, Gaeamsa Temple by conducting a analysis of their wall structure, material characteristics, and painting layers. Wall was a single-branch structure with support layer, middle layer, finishing layer, and painting layer. The support layer, middle layer and finishing layer, were produced by mixing sand (quartz, feldspars etc.), and loess. The ratio of above medium sand to below fine sand was approximately 0.7 : 9.3 in the support layer, 4 : 6 in the middle layer and 6 : 4 in the finishing layer, which had a more percentage of above medium sand than the support layer. The analysis of the painting layer showed that natural soil pigment was used to establish a relatively ground layer of up to 50 ㎛, and pigments such as Lead sulfate, atacamite and mercury sulfide were painted on top of the layer. This study's results confirmed that the bracket mural paintings in Gaeamsa Temple are within the category of the production style of murals during the Joseon period. However, the points that the middle layer was formed several times, the significant difference in particle size distribution between the wall, and the absence of chopped straw in the support layer are a feature of bracket mural paintings in Gaeamsa Temple. These properties of murals as material and structure may be viewed for correlation with the degree of damage to wall structure of mural painting and would serve as an important reference to diagnosis the conservation conditions of murals or prepare conservation treatments.

• 자원환경지질
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• 제56권6호
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• pp.781-797
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• 2023

최근 들어 첨단산업에 활용되는 핵심광물의 확보를 위한 광물수요국들의 대응이 빠르게 진행되고 있다. 흑연은 중국 생산량이 압도적 우위에 있지만, EV 배터리 부문의 기하급수적인 성장에 따라 글로벌 공급에서 변화가 초래되고 있으며, 동 아프리카에서의 활발한 탐사가 좋은 사례이다. 우리나라에서도 생산이 증가되고 있다. 희토류는 첨단산업에 폭넓게 사용되고 있는 핵심원료이다. 세계적으로 희토류를 생산하는 광상은 카보너타이트형, 라테라이트형 및 이온흡착형 광상이 개발 중에 있다. 중국의 생산이 다소 감소되는 추세이지만 여전히 압도적인 우위를 점하고 있다. 최근 수년간의 변화는 미얀마의 급부상과 베트남의 생산 증가이다. 니켈은 다양한 화학 및 금속 산업에 사용되어 온 금속이지만 최근 밧데리 비중이 점차 증가되고 있는 추세이다. 세계 니켈 광상은 초염기성암에서 유래된 유화형 광상과 라테라이트형 광상으로 크게 구분된다. 유화형 광상은 호주에서 개발이 지속적으로 증가 할 것으로 예측되며, 라테라이트형 광상은 인도네시아에서의 개발이 촉진 될 것으로 보인다. 리튬이온 배터리 수요에 따라 니켈 시장도 견인될 것으로 전망된다. 세계 리튬 광상은 염호형(78%)과 암석/광물형(스포듀민 19%), 점토형(3%)이 생산되고 있다. 암석형 광상이 염호형 광상보다 품위가 다소 높지만 매장량이 적고 페그마타이트에 함유된 스포듀민 리튬광물이 대상이다. 칠레, 아르헨티나, 미국에서는 염호형 광상을 주로 개발하고 있으며, 호주와 중국에서는 염호 및 암석/광물 두 근원으로부터 리튬을 추출하고 있고 캐나다에서는 암석/광물로부터만 생산한다. 바나듐은 전통적으로 강철 합금에 약 90% 이용되어 왔으나 최근 대규모 전력 저장을 위한 바나듐 레독스 흐름배터리 용도가 증가 추세에 있다. 세계 바나듐 공급원은 광산에서 생산하는 바나듐을 함유한 철광석(81%)과 부산물에서 회수하는 바나듐(2차 근원, 18%)으로 양대분 된다. 81%를 차지하는 바나듐-철광석 근원은 제강공정에서 유래된 바나듐 슬래그가 70%를 차지하고 광산에서 생산하는 1차 근원인 광석은 30%에 불가하다. 이러한 공급원으로부터 중간재인 바나듐 산화물이 제조된다. 바나듐 광상은 함바나듐 티탄자철석형 광상, 사암 모암형 광상, 셰일 모암형 광상과 바나듐산염형 광상으로 구분되는데 함바나듐 티탄자철석형 광상만이 현재 개발되고 있다.

• Applied Biological Chemistry
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• 제50권4호
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• pp.281-286
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• 2007

본 연구의 목적은 김치에 분말상태의 녹차를 첨가하고, 김치에 첨가된 녹차가 젖산균의 산생성과 생육, 관능적특성 및 몇 가지 휘발성냄새성분에 미치는 영향을 조사하고자 하는 것이다. 김치 제조원료에 분말녹차를 0.2, 0.4, 0.6, 1.2%(w/w)의 농도로 첨가하였다. pH는 녹차의 첨가농도가 증가함에 따라 비숙성시료와 숙성1일에는 약간 증가하였으나, 숙성2일과 숙성3일에는 보다 현저하게 증가하였다. 산도는 녹차의 첨가농도가 증가함에 따라 비숙성시료와 숙성1일에는 대체적으로 증가하였으나, 숙성2일과 숙성3일에는 대체적으로 감소하였다. 한편 녹차의 첨가로 젖산균수는 대체적으로 큰 변화가 없었다. 전반적인 기호도, 맛, 냄새는 녹차 0.2% 또는 0.4% 첨가시료가 다른 시료보다 관능성이 우수하였고, 조직감은 숙성2일 또는 숙성3일시료의 경우 녹차의 첨가농도가 높을 때 관능성이 저하되었다. 색상은 녹차의 첨가농도가 증가할수록 관능성이 저하되었다. 비숙성시료에 비하여 숙성시료에서 diallyl sulfide와 methyl trisulfide가 새로이 생성되었으며, 일부의 냄새성분 함량은 숙성과정 중에 증가하거나 변화를 보였다.