• 한국응용과학기술학회지
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• 제22권3호
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• pp.219-227
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• 2005

Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid $\underline{3}$. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{2}$. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{4}$ showed good selectivity for $Na^+$ over $Mg^{2+}$, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of $Na^+$ as the second extracted ion was much better crown ether carboxylic acid $\underline{1}$ than crown ether phosphonic acid $\underline{2}$, while the efficiency of $Na^+$ extraction was better $\underline{2}$ (83% total loading) than $\underline{1}$ (32%).

• 한국가구학회지
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• 제11권1호
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• pp.1-11
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• 2000

While furniture making in general has been traditionally regarded as labor-intensive industry, the making of metal furniture has immense potential in terms of its growth and as a value added industry. Granted that the technology and designing of metal furniture in Korea are still behind the standards enjoyed by the developed nations of the world, still its future here is promising when we consider the comparatively short history of its industry, Korea depends on imports from abroad for almost all the natural resources she needs for industry. Metal (especially iron) industry is, however, one field where she has some advantage over other nations. Korea is a major producer of iron and her technology in this field is competitive in the international market. When viewed from the points of environment and ecology metal furniture has good points, as metals are recyclable when they are discarded and collected properly according to their reusability. This adds to the merits its industry has here as this country, with her limited natural resources, has yet to solve the pressing problem of disposing ever-increasing waste matter from homes and factories.

• 대한화학회지
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• 제38권2호
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• pp.129-135
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• 1994

Acyclic polyether dicarboxylic acid는 액체막계에서 금속이온의 운반체로 연구되었다. 수소이온이 이온화될 수 있는 리간드는 금속이온의 이동에 수소이온이 반대방향으로 이동된다. 이와 같은 리간드는 pH를 변화시키면 효과적으로 금속이온을 분리할 수 있고 농축시킬 수도 있다. 금속이온의 이동은 source phase의 염기의 농도와 receiving phase의 산의 농도를 증가시키면 증가된다. Acyclic polyether dicarboxylic acids를 운반체로 사용한 경쟁이동반응에서 칼슘이온을 선택적으로 분리할 가능성이 있다.

• Journal of Photoscience
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• 제12권1호
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• pp.47-50
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• 2005

Mediumeffects have been explored on the competitive H-atom abstraction and SET-promoted, silyl-transfer reactions of excited states of silylalkyl-substituted phenyl ketones. The chemical selectivities of photochemical reactions of silylalkyl phenyl ketones appear to depend on medium polarity, medium silophilicity, added metal cation and alkyl length. Irradiations of silylalkylketones in aqueous solvent system and in presence of metal cation such as $Li^+$ and $Mg^{+2} $lead to formation of acetophenone predominantly by the sequential SET-silyl transfer route.

• Bulletin of the Korean Chemical Society
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• 제17권12호
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• pp.1109-1111
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• 1996

The Podand Ⅰ (Figure 1) has been studied as cation carrier in a bulk liquid membrane system. Ag+ and some other transition metal ions (M2+=Cu, Ni, Co, Zn, and Cd) have been transported using the podand as carrier in a bulk liquid membrane system. Studies on the transport of equimolar mixtures of two or three competing components have also been carried out with the same system. Ag+ exhibited a higher transport rate than the other M2+ in the competitive experiments. Ligand structure and the equilibrium constant for complex formation are important parameters in the transport of the metal ions.

• 한국지반신소재학회논문집
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• 제11권1호
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• pp.1-9
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• 2012

본 연구에서는 PRE의 반응물질로 음식물 쓰레기 처리과정에서 발생하는 음식물 쓰레기 탄화재(CFW, Carbonized Foods Waste)를 적용하고자 회분석 흡착실험(Batch test)을 실시하였다. 중금속 구리와 아연에 대한 흡착특성 분석을 위해 CFW를 이용한 개별 및 경쟁흡착 특성을 확인하고자 하였다. 개별흡착 실험에서는 Langmuir와 Freundlich 모델에 적용하여 흡착평형을 예측한 결과 Langmuir의 모델에 더 일치하였고 최대흡착량은 구리가 더 많았다. 유사일치반응과 유사이차반응모델을 이용한 흡착물질의 흡착속도를 비교한 결과 아연의 반응속도가 구리보다 빨랐다. CFW를 이용한 중금속 제거는 구리보다 아연이 먼저 제거가 될 것으로 판단된다. 한편 구리와 아연과의 경쟁흡착 비율이 유사하면 아연의 흡착량이 떨어지는 특성을 보였다. 구리용액에 이연을 혼합한 경우, CFW에 구리의 흡착은 86%이고, 아연용액에 구리를 혼합한 경우에는 이연의 흡착이 19%로 나타났다. 따라서, 복합 중금속으로 오염된 지반의 효율적인 오염제거를 위해서는 각 중금속의 정화특성이 고려되어야 할 것으로 판단된다.

• 한국식품영양과학회지
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• 제9권1호
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• pp.59-73
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• 1980

A detailed procedure was described for the isolation of cratine kinase (ATP-Creatine phosphotransferase, E. C. 2. 7. 3. 2.) from the muscle of the snake Bungarus fasciatus. The original isolation procedure of Kuby et al. for the rabbit muscle enzyme has been modified and extended to include a chromatographic step. The properties of the enzyme have been investigated and kinetic constants for the reverse reactions determined as the followings: 1) A molecular weight of the enzyme was determined by gel filteration on Sephadex G-100 and by electrophoresis on SDS-polyacrylamide was 86,000. 2) Two reactive sulphydryl groups were detected with dithiobis nitrobenzoic acid (DTNB). 3) The nucleotide substrate specificity in the reverse reaction was determined as ADP*2'-dADP＞GDP＞XDP＞UDP with magnesium as the activating metal ion. 4) The order of the metal specificity in the reverse reaction Mg>Mn>$Ca{\sim}Co$ was determined with ADP as substrate. 5) A detailed kinetic analysis was carried out in the reverse direction with $MaADP^-$ as the nucleotide substrate. Initial velocity and product inhibition studies($MaADP^{2-}$ competitive with respect to MgADP- and noncompetitive with respect to $N-phosphorycreatine^{2-}$ ; Creatine competitive with respect to $N-phosphorycreatine^{2-}$ and noncompetitive with respect to Ma $ADP^-)$ indicated that the reaction obeyed a sequential mechanism of the rapid equilibrium random type.

• 한국CDE학회논문집
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• 제9권2호
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• pp.133-142
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• 2004

CAMPfonn2D is a Finite Element Method (FEM) based process simulation system designed to analyze two dimensional (2D) flow of various metal forming processes. It enables designers to analyze metal forming processes on the computer rather than the shop floor using trial and error and provides vital information about material and thermal flow during the forming process to facilitate the design of products. CAMPfonn2D can be used by companies, research institutes and industrial applications to analyze forging, extrusion, drawing, heading, upsetting and many other metal forming processes. Also, process simulation using CAMPfonn2D can be instrumental in cost, quality and delivery improvements at leading companies. Today's competitive pressures require companies to take advantage of every tool for rapid manufacturing of well-designed product. So, the preprocessor of simulation program must be easy to use to speed-up design. In this paper, we introduce new version of Preprocessor and show how easy to use it. And, Preprocessor will prove itself to be easy and extremely effective.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.714-715
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• 2006

The Application of powder metallurgy (PM) aluminum structural parts is at its early growing stage, despite of some automotive applications. The market potential for PM aluminum, however, is large. Growth is expected from the market expansion of the existing applications and new applications, including the replacements of aluminum and zinc based castings and some ferrous PM automotive parts by PM aluminum. Compared to castings, PM is an efficient mass production technology. The PM aluminum is more competitive than die casting for some automotive applications. Besides weight saving leading to performance improvement, the total cost increase for aluminum PM parts is less than 15% compared to ferrous PM automotive parts. The future is promising for PM aluminum.

• Journal of Korean Vacuum Science & Technology
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• 제7권2호
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• pp.45-56
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• 2003

A high flux metal plasma pulse ion source, which can simultaneously perform ion implantation and deposition, was developed and tested to evaluate its performance using the prototype. Flux of ion source was measured to be 5 A and bi-polar pulse power supply with a peak voltage of 250 V, repetition of 20 Hz and width of 100 ${\mu}\textrm{s}$ has an output current of 2 kA and average power of 2 kW. Trigger power supply is a high voltage pulse generator producing a peak voltage of 12 kV, peak current of 50 A and repetition rate of 20 Hz. The acceleration column for providing target energy up to ion implantation is carefully designed and compatible with UHV (ultra high vacuum) application. Prototype systems including various ion sources are fabricated for the performance test in the vacuum and evaluated to be more competitive than the existing equipments through repeated deposition experiments.