• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.156-161
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• 2004

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. In order to compare the removal rate and non-uniformity as a function of oxidizer contents, we used alumina-based tungsten slurry and copper blanket wafers deposited by DC sputtering method. According to the CMP removal rates and particle size distribution, and the microstructures of surface layer by SEM image as a function or oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_2$O$_3$abrasive particles in CMP slurry.

• Journal of environmental and Sanitary engineering
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• v.18 no.2
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• pp.34-41
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• 2003

The purpose of this study is to examine the effect of stabilization disposal and recycling on incinerated paper mill sludge ash as cement additives. It was investigated chemical(pH, ICP, TGA XRD) and physical(PDA, SEM) characteristics of the incineration ash. And the pozzolanic characteristics of incineration ash was applied to cement as additive to increase the compressive strength. The results were that the pH characteristic of incineration ash was strong alkalinity, the content of silica and alumina as a pozzolanic material was 50.97%, and the average particle size was $5.03{\mu}m$ respectively. When the ash contents as cement additive were varied in 0~15%(wt) of cement weight to explore the effect of the compressive strength on the solidified cement mortar, the proper amount of the incineration ash substituted was about 5~l0%(wt). Therefore we found that using the incineration ash as cement additive obtains the recycling of waste material, the stabilization disposal, the reduction of waste disposal expense, and the protection of environmental problem, too.

• Advances in Computational Design
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• v.1 no.1
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• pp.27-35
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• 2016

The influences of chloride-free components of the cement additive: triethanolamine, triisopropanolamine, sodium hyposulfite and calcium gluconate on the 1d, 3d and 28d compressive strength of cement were investigated by response surface methodology. It found the early strength activators, triethanolamine and sodium hyposulfite could enhance the 1d strength of cement effectively but they did not contribute to the 3d strength enhancement, and further their interaction was able to decrease the 28d strength of cement. Calcium gluconate was not that effective for the strength enhancement on 3 and 28 days when it's simply dosed. However the interaction effect of calcium gluconate with triisopropanolamine could strongly favor the strength enhancement of cement after 3 days. Results indicated it was necessary to focus attention on the potential interactions among the chemical components. And for the concern of four chemicals studied in this paper, it was feasible to formulated a kind of chloride-free cement additive that can be effective for the early strength of cement and its the strength after 3 days.

• Journal of the Semiconductor & Display Technology
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• v.3 no.1
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• pp.15-20
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• 2004

Through shallow trench isolation (STI) chemical mechanical polishing (CMP) tests, we investigated the dependence of pad surface temperature on the abrasive and additive concentrations in ceria slurry under varying pressure using blanket film wafers. The pad surface temperature after CMP increased with the abrasive concentration and decreased with the additive concentration in slurries for the constant down pressure. A possible mechanism is that the additive adsorbed on the film surfaces during polishing decreases the friction coefficient, hence the pad surface temperature gets lower with increasing the additive concentration. This difference in temperature was more remarkable for the higher concentration of abrasives. In addition, in-situ measurement of spindle motor was carried out during oxide and nitride polishing. The averaged motor current for oxide film was higher than that for nitride film, meaning the higher friction coefficient.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.122-125
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• 2003

We investigated the effect of the abrasive and additive concentrations in Nano ceria slurry on the pad surface temperature under varying pressure through chemical mechanical polishing (CMP) test using blanket wafers. The pad surface temperature after CMP increased with the abrasive concentration and decreased with increase of the additive concentration in slurries for the constant down pressure. A possible mechanism is that the additive adsorbed on the film surface during polishing decreases the friction coefficient, hence the pad surface temperature gets lower with increase of the additive concentration. This difference of temperature was more remarkable for the higher concentration of abrasives. In addition, in-situ measurement of spindle motor was carried out during oxide and nitride polishing. The averaged motor current for oxide film was higher than that for nitride film, which means the higher friction coefficient.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.10-16
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• 2004

The Homogeneous Charge Compression Ignition (HCCI) engine has advantage for reducing the NOx and P.M. simultaneously. Therefore, HCCI engine is receiving attention as a low emission diesel engine concept. This study was carried out to investigate the characteristics of combustion and exhaust emission for operating conditions in a direct injection type of HCCI engines such as supercharged and naturally aspirated using diesel fuel and additive. From the experimental result, we found that cool flame was always appeared and also it was difficult to control combustion characteristics by changing the injection timing in HCCI. In addition, at the lean air-fuel ratio and high speed range, it was observed that charging air pressure, additive or increasing intake air temperature is effective to increase combustion performance and reduce exhaust emission. We concluded that chemical reaction by the increasing intake air temperature or additive without physical improvement has limitation for reduction of exhaust emission.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.241-246
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• 2003

Numerical simulations are performed at atmospheric pressure in order to understand the effect of additives on flame speed and the NOx formation in freely propagating $H_{2}/O_{2}/N_{2}$ flames with oxygen enrichments. A chemical kinetic mechanism is developed, which involves 26 gas-phase species and 99 reactions. Under several equivalence ratios and oxygen enrichments, flame speeds are calculated and compared with those obtained from the experiments, the results of which is in good agreement. As hydrogen chloride as additive is added into $H_{2}/O_{2}/N_{2}$ flames with low oxygen enrichments, its chemical effect causes the decrease of flame speed, radical concentration, and the NO production rate. It is found that the chemical effect of additive has much more influence on the reduction of EINO than its physical effect. However, in flames with very high flame temperature the physical effect rather than the chemical effect becomes more important on the reduction of EINO.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1107-1112
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• 2008

Crystallization of calcium carbonate was performed by using aqueous calcium chloride and sodium carbonate for operational simplicity. Reaction time, solute concentrations, pH, and organic additive were varied to get calcium carbonate crystals. Silk fibroin was used as the additive to understand the change of morphology of calcium carbonate crystal. The crystals were analyzed by FE-SEM, XRD, and FT-IR. Reaction time, and pH mainly affected the morphology of crystals. Besides, it was found that silk fibroin inhibited the formation of vaterite and promoted the calcite forms.

• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.53-60
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• 2017

Fluoroethylene carbonate (FEC) was studied as an additive for the electrolyte in lithium ion batteries with the $LiNi_{0.5}Mn_{1.5}O_4$ (LNMO) spinel cathode operating at a high potential beyond 4.7 V (vs. $Li/Li^+$). It was found that the FEC additive was electrochemically active for the $1^{st}$ charge cycle on the LNMO cathode. The presence of a large amount of FEC (more than 40 vol%) in the electrolyte caused severe side reactions with abnormally long voltage plateaus. In contrast, when the electrolyte contained less than 30 vol% FEC, the surface of the LNMO cathode was stabilized by the formation of the solid-electrolyte interphase (SEI), leading to improved cyclability. However, the resistance from the SEI limited the rate capability because of sluggish lithium transportation through the SEI and electronic insulation between the particles in the electrode.

• Membrane Journal
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• v.18 no.4
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• pp.317-324
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• 2008

Polysulfone membranes were prepared via the phase inversion process. With propionic acid as a nonsolvent additive, polysulfone casting solutions were solidified in an isopropanol bath. Propionic acid (PA) worked as a thermodynamic enhancer for phase separation and as a rheological suppressor for kinetic hindrance. Morphology of the prepared membranes significantly varied with propionic acid content in the casting solution. The dense skin layer, which was identified in the membrane prepared without PA, almost disappeared in the membrane prepared trom PA 10wt%. With 30wt% PA, the membrane revealed the morphological gradient from a nodular skin structure to a sponge-like substructure, including the finger-like cavity. Water permeability increased with PA content, and polyethylene glycol rejection decreased with the nonsolvent content.