• Title/Summary/Keyword: Removal mechanism

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Characterization of Natural Organic matter by Rapid Mixing Condition (급속교반조건에서 Alum 응집제의 가수분해종 분포특성과 유기물특성변화)

  • Song, Yu-Kyung;Jung, Chul-Woo;Son, Hee-Jong;Sohn, In-Shik
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.4
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    • pp.559-571
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    • 2006
  • The overall objective of this research was to find out the interrelation of coagulant and organic matter during rapid mixing process and to identify the change of organic matter by mixing condition and to evaluate the effect of coagulation pH. During the coagulation, substantial changes in dissolved organics must be occurred by coagulation due to the simultaneous formation of microflocs and NOM precipitates. Increase in the organic removal efficiency should be mainly caused by the removal of microflocs formed during coagulant injection. That is, during the mixing period, substantial amount of dissolved organics were transformed into microflocs due to the simultaneous formation of microflocs and NOM precipitates. The results also showed that 40 to 80% of dissolved organic matter was converted into particulate material after rapid mixing process of coagulation. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) constant by rapid mixing condition, but for raw water, the species of Al hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_3(s)$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

The Cu-CMP's features regarding the additional volume of oxidizer to W-Slurry (W-slurry의 산화제 첨가량에 따른 Cu-CMP특성)

  • Lee, Woo-Sun;Choi, Gwon-Woo;Seo, Young-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.370-373
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    • 2003
  • As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Chemical-Mechanical Planarization(CMP) of conductors is a key process in Damascene patterning of advanced interconnect structure. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. Electroplated copper depostion is a mature process from a historical point of view, but a very young process from a CMP persperspective. While copper electrodepostion has been used and stuidied for dacades, its application to Cu damascene wafer processing is only now ganing complete accptance in the semiconductor industry. The polishing mechanism of Cu CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. however it is important to understand the effect of oxidizer on copper pasivation layer in order to obtain higher removal rate and non-uniformity during Cu-CMP process. In this paper, we investigated the effects of oxidizer on Cu-CMP process regarding the additional volume of oxidizer.

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A Study on Micro Ultrasonic machining for Brittle Material Using Ultrasonic vibration (초음파 진동을 이용한 취성재료의 가공기술에 관한 연구)

  • Lee Seok-Woo;Choi Heon-Jong;Yi Bong-Gu
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.245-252
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    • 2002
  • Ultrasonic machining technology has been developed over recent years for the manufacture of cost-effective and quality-assured precision parts for several industrial application such as optics, semiconductors, aerospace, and automobile. Ultrasonic machining process is an efficient and economical means of precision machining of ceramic materials. The process is non-thermal, non-chemical and non-electric md hardly creates changes to the mechanical properties of the brittle materials machined. This paper describes the characteristics of the micro-hole of $Al_2O_3$ by ultrasonic machining with tungsten carbide tool. The effects of various parameters of ultrasonic machining, including abrasives, machining force and pressure, on the material removal rate, hole quality, and tool wear presented and discussed. The ultrasonic Machining of micro-holes in ceramics has been under taken and the machining mechanism in the ultrasonic machining of ceramics based on the fracture-mechanics concept has been analyzed.

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Copper Uptake by Tyromyces palustris (Tyromyces palustris를 이용한 구리의 제거)

  • Son, Dong-Weon;Lee, Dong-Heub;Kang, Chang-Ho
    • Journal of the Korean Wood Science and Technology
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    • v.26 no.1
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    • pp.57-62
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    • 1998
  • In this research, the removal or uptake of heavy metals such as coppers by using oxalic acid metabolism of wood rot fungi, Tyromyces palustris were endeavored. As results, the addition of oxalic acid to copper containing culture did not cause the mycelium growth, but Tyromyces palustris was able to grow in this culture without inhibition. Tyromyces palustris grew with the cicular halo type in copper containing culture, and this type was formed as collectives after examining by microscope, and considered as copper oxalates by analyzing FT-IR comparison experiment with standards. According to this result, Tyromyces palustris has secreted oxalic acid during incubation, this secreted oxalic acid was combined with coppers, and formed copper oxalates by chelating reactions. In other words, the oxalic acid was might be as non-toxifying agent of coppers in medium. By using this copper removal mechanisms, Tyromyces palustris immobilized sawdust was used in bench scale air lift system for removing coppers. The added coppers were almost removed from the system within 72hrs. Therefore, this nonenzymatic wood degradation mechanism may give a possibility for removing coppers from copper containing waste water.

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Radiation Treatment of Terephthalic Acid and Ethylene Glycol by using Gamma-rays (감마선을 이용한 테레프탈산과 에틸렌글리콜의 방사선처리)

  • Lee, Sun-Mi;Jo, Hun-Je;Kim, Jeong-Gyu;Jung, Jinho
    • Journal of Korean Society on Water Environment
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    • v.20 no.5
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    • pp.452-456
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    • 2004
  • Gamma-rays effectively decomposed TPA and EG, thus removal of $1.0{\times}10^{-3}$ M pollutants was near 65 and 95%, respectively, at an absorbed dose of 10 kGy. However, TOC removal in the radiation treatment was less than 5% due to a low transformation of both TPA and EG to $CO_2$. For TPA, gamma-ray treatment largely reduced biodegradability($BOD_5/COD$) by degrading TPA to non-biodegradable organic acids. This implies that the change of biodegradability should be considered when the radiation treatment is combined with conventional biological techniques. A weight-loss wastewater containing TPA and EG was also purified by gamma-ray treatment. Extraordinarily, biodegradability of the wastewater was increased at a low dose of 1 kGy. Though underlying mechanism was not clearly identified, this result stresses the effect of wastewater composition and absorbed dose on the biodegradability change.

A Study on a Development of the Grinding Robot to Remove Welding-bid of Working Pieces (취부용 피스(piece)제거 및 사상 작업 자동화장비 개발에 관한 연구)

  • Noh, Hyo-Won;Kim, Ki-Jung;Leem, Rae-Soo;Kim, Ho-Kyoung
    • Special Issue of the Society of Naval Architects of Korea
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    • 2008.09a
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    • pp.136-143
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    • 2008
  • This paper presents the application of a robot which aims at grinding automatically welding-bead remained in the removal job of working pieces for shipbuilding. In specific, the investigation on this application is composed of two parts; one topic is on the development of a robot platform vertically movable on a steel plate of hull, while the other topic is of the development of a grinding tool mechanism in order to remove welding-beads by using a diamond wheel installed on a servo cylinder (which can result in high working pressure on the grinding wheel). Besides, the development of a vision system for tracking welding-beads as well as recognizing welding surfaces is added for the convenience of this robot application to the removal of welding-beads remained in the working pieces for shipbuilding.

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MRR model for the CMP Process Considering Relative Velocity (상대속도를 고려한 CMP 공정에서의 연마제거율 모델)

  • 김기현;오수익;전병희
    • Transactions of Materials Processing
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    • v.13 no.3
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    • pp.225-229
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    • 2004
  • Chemical Mechanical Polishing(CMP) process becomes one of the most important semiconductor processes. But the basic mechanism of CMP still does not established. Slurry fluid dynamics that there is a slurry film between a wafer and a pad and contact mechanics that a wafer and a pad contact directly are the two main studies for CMP. This paper based on the latter one, especially on the abrasion wear model. Material Removal Rate(MRR) is calculated using the trajectory length of every point on a wafer during the process time. Both the rotational velocity of a wafer and a pad and the wafer oscillation velocity which has omitted in other studies are considered. For the purpose of the verification of our simulation, we used the experimental results of S.H.Li et al. The simulation results show that the tendency of the calculated MRR using the relative velocity is very similar to the experimental results and that the oscillation effect on MRR at a real CMP condition is lower than 1.5%, which is higher than the relative velocity effect of wafer, and that the velocity factor. not the velocity itself, should be taken into consideration in the CMP wear model.

Zeta Potential Measurement of Micro Bubbles Generated by Electrolysis (전기분해(電氣分解)시 알루미늄 극판(極板)에서 발생(發生)한 미세기포(微細氣泡)의 제타전위(電位) 측정(測定))

  • Kim, Won-Tae;Han, Moo-Young;Lee, Sung-Woo;Han, Yi-Seon
    • Journal of Korean Society of Water and Wastewater
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    • v.14 no.4
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    • pp.343-349
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    • 2000
  • Techniques such as dissolved air flotation and electroflotation, which utilize micro bubbles, are increasingly used for water and wastewater treatment. Most studies have concentrated on particle characteristics. Pretreatments that manipulate particle size and zeta potential were considered important. A recent study, which modeled the collision mechanism between micro bubbles and particles in dissolved air flotation, suggested bubble characteristics should also be important. Hydrogen micro bubbles were generated electrolytically and their zeta potentials measured under various conditions using a novel electrophoresis method. Effects of several parameters were investigated. Bubble zeta potentials were found to be pH dependent, and to have a negative value around neutral pH, becoming zero or positive at lower pH. The pH at zero zeta potential was 5.0 under study conditions. Using artificial solution and tap water, at fixed pH, bubble zeta potentials varied with solution composition. Zeta potentia]s of bubbles were affected by the types of cations and anions in solution but not by the voltage applied. These findings will help improve efficiencies of particle removal processes that utilize micro bubbles. As bubble zeta potential varies with solution composition, it needs to be measured for each composition to understand those effects, which increase removal efficiency.

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Removal of Hexavalent Chromium by using Biomass (바이오매스를 이용한 6가 크롬의 제거)

  • Park, Donghee;Park, Jong Moon
    • Korean Chemical Engineering Research
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    • v.44 no.2
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    • pp.107-113
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    • 2006
  • Not only Cr(VI) is very toxic, but also it is a major pollutant in soil and groundwater. Thus Cr(VI)-containing wastewater must be treated before being discharged into the environments. Recently, biosorption technology using abundant biomass has been considered as an innovative one for removing Cr(VI) from aqueous solution. In this review article, current research and future works on Cr(VI) biosorption were widely described. Particularly, the removal mechanism of Cr(VI) by biomass was described in detail, which has been misunderstood by many researchers until now.

Sorption of Ni(II), Cu(II) and Fe(III) ions from Aqueous Solutions Using Activated Carbon (활성탄소를 이용한 수용액으로부터의 Ni(II), Cu(II) 그리고 Fe(III) 이온의 흡착)

  • Hanafi, H.A.;Hassan, H.S.
    • Journal of the Korean Chemical Society
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    • v.54 no.5
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    • pp.533-540
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    • 2010
  • An activated carbon was tested for its ability to remove transition metal ions from aqueous solutions. Physical, chemical and liquid-phase adsorption characterizations of the carbon were done following standard procedures. Studies on the removal of Ni(II), Cu(II) and Fe(III) ions were attempted by varying adsorbate dose, pH of the metal ion solution and time in batch mode. The equilibrium adsorption data were fitted with Freundlich and Langmuir and the isotherm constants were evaluated, equilibrium time of the different three metal ions were determined. pH was found to have a significant role to play in the adsorption. The processes were endothermic and the thermodynamic parameters were evaluated. Desorption studies indicate that ion-exchange mechanism is operating.