• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2005년도 제13회 산화철워크샵
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• pp.3-14
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• 2005

We Investigated minutely how the biosorption technology using algal biomass is opened in Canadian technology society. Making comparative study for relative technologies in views of overall unit operation cost, we could grasp next facts. - Algal biomass plays the competitive performance for various metals. - Algal biomass biosorbent is regenerated. - Reactor system is not and involved one. This means that algal biomass occupies the strong position as biosorbent. Especially, in North America, for the purpose of metal bearing wastewater treatment, 20 hundred million US dollars was appropriated a sum for the purchase of ion exchange resin. But it is only thirty million US dollars if algal biomass biosorbent is used on behalf of ion exchange resin. Furthermore, the expenses for same treatment can be cut down additively through metal recovery.

• 상하수도학회지
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• 제26권2호
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• pp.275-283
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• 2012

MCM-41(Mobil's Composition of Matter-41) and expanded graphite(EG) were investigated as potential adsorbents for heavy metal ions including Pb(II), Cu(II) and Ni(II) in various aqueous chemistries. MCM-41 showed shorter equilibrium times and higher adsorption capacities for all three heavy metal ions compared to expanded graphite. The adsorption of three heavy metal ions was significantly affected by the solution pH due to the competition with $H_{3}O^{+}$ at lower pH and precipitation at neutral or higher pH. Adsorptions of heavy metal ions onto MCM-41 and expanded graphite were successfully described with the pseudo-second-order model. During the competitive adsorption of three heavy metal ions, the selectivity of Pb(II) was highest and almost same selectivity was observed with Cu(II) and Ni(II) when MCM-41 was used as an adsorbent, while the expanded graphite exhibited the highest selectivity to Pb(II), followed by Ni(II) and Cu(II).

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2201-2206
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• 2010

To improve the separation property and stability of metal chelate Cu(II) column, three new kinds of multidentate aminocarboxy silica columns with cation-exchange properties were synthesized using glutamic acid (Glu), glutamic acidbromoacetic acid (Glu-BAA), glutamic acid-bromosuccinic acid (Glu-BSUA) as ligands and silica gel as matrix. The standard proteins were separated with prepared chromatographic columns. The stationary phases exhibited the metal chelate property after fixing copper ion (II) on the synthesized multidentate ligand silica columns. The binding capacity of immobilized metal ion was related with the dentate number of multidentate ligands. Chromatographic behavior of proteins and the leakage of immobilized metal ion on multidentate chelate Cu(II) columns were affected by the dentate number of multidentate ligands and competitive elution system directly. The results showed that quinquedentate Glu-BSUA-Cu(II) column exhibited better chromatographic property and stability as compared with tridentate Glu-Cu(II) column, tetradentate Glu-BAA-Cu(II) column and commonly used IDA-Cu(II) column.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.3855-3860
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• 2011

The competitive solvent extractions of alkali and alkaline earth metals by di-ionizable calix[4]arene nano-baskets were studied using nine conformers of calix[4]arene nano-baskets. The objective of this work is to assess the variation of macrocycle conformation, orientation and position of pendant moieties upon the extraction parameters (efficiency, selectivity and $pH_{1/2}$) of the complexes. The results revealed that alternation of ring conformation in calixarene scaffold affects the solvent extraction parameters towards alkali and alkaline earth metals, while changing the orientation of pendant moieties from ortho- to para- as well as cis- to trans-analogues depicted no changes in those extraction parameters.

• 소성∙가공
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• 제12권8호
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• pp.702-709
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• 2003

In the automotive industry hydroforming of sheet metal pairs have received special attention because materials for various sheet metal components of vehicles have changed into the high strength steel, aluminum, and titanium blank having low formability. Uniform deformation over the whole region is a main advantage in the sheet hydroforming process. Because upper and lower parts could be produced simultaneously with one tool, hydroforming of sheet metal pairs is competitive in reducing the lead-time and development cost. In this paper, the multi-stage hydroforming process of sheet pair is proposed in order to increase the formability of a structural part like the oil pan shape. The upper die for forming oil pan shape is divided into two parts which can move separately. By the finite element simulation, the design parameters such as geometry of the tool and detailed specification of hydraulic pump were calculated and verified. For the strict comparison of the proposed process, the blank holding force is kept to a constant value during deformation by hydraulic valve. The deformed shape and strain distribution of the manufactured parts with the proposed process are compared with the results of simulation. In the multi-stage hydroforming process, maximum thickness strain was improved by more than 30 percent.

• 한국환경과학회지
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• 제26권8호
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• pp.955-966
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• 2017

Amendment of multi-binders was employed for the immobilization of metal(loid)s in field-contaminated soils to reduce the leaching potential. The effect of different types of multi-binders (lime/diammonium phosphate, diammonium phosphate/ladle slag and lime/ladle slag) on the solidification/stabilization of metal(loid)s (Pb, Zn, Cu and As) from the smelter soil and mine tailing soil were investigated. The amended soils were evaluated by measuring Toxicity Characterization Leaching Procedure (TCLP) leaching concentration of metal(loid)s. The results show that the leaching concentration of metal(loid)s decreased with the immobilization using multi-binders. In terms of TCLP extraction, the mixed binder was effective in the order of lime/ladle slag > diammonium phosphate/ladle slag > lime/diammonium phosphate. When the mixed binder amendment (0.15 g lime+0.15 g ladle slag for 1g smelter soil and 0.05 g lime+0.1 g ladle slag for 1 g mine tailing soil, respectively) was used, the leaching concentration of metal(loid)s decreased by 90%. However, As leaching concentration increased with diammonium phosphate/lime and diammonium phosphate/ladle slag amendment competitive anion exchange between arsenic ion and phosphate ion from diammonium phosphate. The Standard, Measurements and Testing programme (SM&T) analysis indicated that fraction 1 (F1, exchangeable fraction) decreased, while fraction 4 (F4, residual fraction) increased. The increased immobilization efficiency was attributed to the increase in the F4 of the SM&T extraction. From this work, it was possible to suggest that both arsenic and heavy metals can be simultaneously immobilized by the amendment of multi-binder such as lime/ladle slag.

• 공업화학
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• 제3권2호
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• pp.266-272
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• 1992

아자크라운에테르가 부착된 알킬 페닐포스피닉산을 합성하여 수용액층으로부터 클로로포름층으로 알카리금속이온의 경쟁용매추출 특성을 조사하였다. 연구된 포스피닉산들은 phenylphosphinate, aldehyde 그리고 monoazacrown ether의 한 단계 반응에서 생성되는 포스피네이트 에스테르를 알카리성 가수분해시켜 좋은 수율로 합성할 수 있었다. 합성된 포스피닉산 시약을 착물화제로 사용하여 pH에 따라 수용액층으로부터 클로로포름층으로 알카리 금속이온의 경쟁용매추출 특성을 조사한 결과 이 시약들은 넓은 pH 영역에서 금속이온을 유기용매층으로 추출해냄을 확인하였으며, pH 11인 알카리성 용액에서의 총금속이온부하는 약 75%였다. 이온의 선택성은 아자크라운에테르의 공동크기에 주로 의존하여, monoaza-15-crown-5 기를 갖는 알킬페닐포스피닉산, ${\underline{2}}$, 에서는 $Na^+$ >> $K^+$ > $Rb^+$ > $Li^+$ > $Cs^+$ 순이며 monoaza-18-crown-6 작용기가 있는 알킬페닐포스피닉산, ${\underline{3}}$, 에서는 $K^+$ >> $Rb^+$ > $Na^+$ > $Cs^+$ > $Li^+$ 이온의 순으로 나타났다. 아자크라운에테르포스피닉산들은 유사한 이온선택성을 지닌 크라운에테르카르복실산에 비해 보다 넓은 영역의 pH에서 알카리금속이온의 용매추출이 가능하여, 약한 산성이나 중성 수용액에서도 상당한 정도의 금속이온부하를 나타내었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1767-1770
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• 2007

The key development issues in the flexible displays are TFT backplane technology for their various applications, which requires competitive device performance as well as its low temperature process. In this paper, with shortly reviewing recent flexible display development status, we describe technical trends of low-temperature a-Si TFTs. Our TFTs show good device characteristics enough to apply LCD and electrophoretic display.

• Design & Manufacturing
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• 제7권1호
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• pp.40-44
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• 2013

My company develops, manufactures injection mold and produces thin-walled cosmetics and food containers. Without high quality and low production cost, it is hard to compete in the market. To be competitive, a company has to utilize mold with as many cavities as possible to lower manufacturing cost. Eject plate abrasion and deformation cut down mold lifespan, troubles during injection lower productivity and foreign substances in molds cause abrasion. This study focuses on how to improve mold life and productivity, and to slow down mold abrasion.

• Advances in Traditional Medicine
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• 제7권2호
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• pp.162-170
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• 2007

Woodfordia fruticosa Kurz. (Lythraceae), commonly known as Dhayero, is used in the treatment of various ailments in Nepal. In this study, the antioxidant capacity of crude extract and different polarity fractions of Woodfordia fruticosa flowers were assayed for their scavenging abilities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide radicals, competitive ${\beta}$-carotene bleaching, reducing power, metal chelating ability and total phenolic content. Crude extract and polar fractions showed stronger antioxidant capacity and contained very high level of total phenolics. They exhibited strong DPPH radical scavenging, nitric oxide scavenging and reducing power, medium ${\beta}$-carotene bleaching and poor metal chelating capacity. Positive correlation obtained between total phenolic content and antioxidant capacity assays, indicated the contribution of phenolics toards antioxidant capacity.