• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.168-168
• /
• 2006

Low-operating voltage organic field-effect transistors (OFETs) have been realized with high dielectric constant (${\kappa}$) polymer such as cyanoethylated poly vinyl alcohol (CR-V, ${\kappa}=12$). Since the $high-{\kappa}$polymers are likely to contain water and ionic impurities, large hysteresis and considerable leakage current are frequently observed in OFETs. To solve these problems, we cross-linked the CR-V by using a cross-linking agent. Cross-linked CR-V dielectrics showed high dielectric constant of 11.1 and good insulating properties, resulting in a high capacitance ($81nF/cm^{2}$ at 1MHz) at 120 nm of dielectric thickness. Pentacene FETs with cross-linked CR-V dielectrics exhibited high carrier mobility ($0.72\;cm^{2}/Vs$), small subthreshold swing (185 mV/dec) and little hysteresis at low-operating voltage (${\Leq}-3V$).

• Nuclear Engineering and Technology
• /
• v.12 no.1
• /
• pp.29-38
• /
• 1980

A radiochemical separation scheme for the neutron activation analysis is developed for the determination of 28 elements in aluminum. The scheme is based on a group separation using ion-exchange resin and mineral exchanger. Present work has employed mineral acids and their partly organic mixture excluding HF as the media as well as common glass wares. For the determination, gamma-ray spectroscopy using $3"\times3"\;Nal(TI)$ detector and a single comparator method are used.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.1
• /
• pp.6-10
• /
• 2016

In this study, the effects of soft baking temperature on the solution derived ZTO (Zn-Sn-O) TFTs (thin-film transistors) as a In-free oxide semiconductor were investigated. In spite of the same hard baking at high temperature($600^{\circ}C$), the electrical properties of ZTO TFT was greatly changed by a small difference in soft baking temperature($180{\sim}250^{\circ}C$). The performance of TFT was deteriorated as the soft baking temperature increased. Therefore, it is important to remove the water-related defects well as organic impurities from the ZTO films during soft baking for fabrication of solution-derived high performance of TFTs.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2004.09a
• /
• pp.233-241
• /
• 2004

A new alloy definition will be presented concerning increasing demands for the board level reliability of miniaturized interconnections. The damage mechanism for LFBGA components on different board finishes is not quite understood. Further demands from mobile phones are the drop test, characterizing interface performance of different package constructions in relation to decreased pad constructions and therefore interfaces. The paper discusses the characterization of interfaces based on SnPb, SnPbXYZ, SnAgCu and SnAgCuInNd ball materials and SnAgCuInNd as solder paste, the stability after accelerated tests and the description of modified interfaces strictly related to the assembly conditions, dissolution behavior of finishes on board side and the influence of intermetallic formation. The type of intermetallic as well as the quantity of intermetallics are observed, primaliry the hardness, E modules describing the ability of strain/stress compensation. First results of board level reliability are presented after TCT-40/+150. Improvement steps from the ball formulation will be discussed in conjunction to the implementation of lead free materials In order to optimize ball materials for area array devices accelareted aging conditions like TCTs were used to analyze the board level reliability of different ball materials for BGA, LFBGA, CSP, Flip Chip. The paper outlines lead-free ball analysis in comparison to conventional solder balls for BGA and chip size packages. The important points of interest are the description of processability related to existing ball attach procedures, requirements of interconnection properties and the knowledge gained the board level reliability. Both are the primary acceptance criteria for implementation. Knowledge about melting characteristic, surface tension depend on temperature and organic vehicles, wetting behavior, electrical conductivity, thermal conductivity, specific heat, mechanical strength, creep and relaxation properties, interactions to preferred finishes (minor impurities), intermetallic growth, content of IMC, brittleness depend on solved elements/IMC, fatigue resistance, damage mechanism, affinity against oxygen, reduction potential, decontamination efforts, endo-/exothermic reactions, diffusion properties related to finishes or bare materials, isothermal fatigue, thermo-cyclic fatigue, corrosion properties, lifetime prediction based on board level results, compatibility with rework/repair solders, rework temperatures of modified solders (Impurities, change in the melting point or range), compatibility to components and laminates.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2004.09a
• /
• pp.211-219
• /
• 2004

A new alloy definition will be presented concerning increasing demands for the board level reliability of miniaturized interconnections. The damage mechanism for LFBGA components on different board finishes is not quite understood. Further demands from mobile phones are the drop test, characterizing interface performance of different package constructions in relation to decreased pad constructions and therefore interfaces. The paper discusses the characterization of interfaces based on SnPb, SnPbXYZ, SnAgCu and SnAgCuInNd ball materials and SnAgCuInNd as solder paste, the stability after accelerated tests and the description of modified interfaces stric시y related to the assembly conditions, dissolution behavior of finishes on board side and the influence of intermetallic formation. The type of intermetallic as well as the quantity of intermetallics are observed, primaliry the hardness, E modules describing the ability of strain/stress compensation. First results of board level reliability are presented after TCT-40/+150. Improvement steps from the ball formulation will be discussed in conjunction to the implementation of lead free materials. In order to optimize ball materials for area array devices accelareted aging conditions like TCTs were used to analyze the board level reliability of different ball materials for BGA, LFBGA, CSP, Flip Chip. The paper outlines lead-free ball analysis in comparison to conventional solder balls for BGA and chip size packages. The important points of interest are the description of processability related to existing ball attach procedures, requirements of interconnection properties and the knowledge gained the board level reliability. Both are the primary acceptance criteria for implementation. Knowledge about melting characteristic, surface tension depend on temperature and organic vehicles, wetting behavior, electrical conductivity, thermal conductivity, specific heat, mechanical strength, creep and relaxation properties, interactions to preferred finishes (minor impurities), intermetallic growth, content of IMC, brittleness depend on solved elements/IMC, fatigue resistance, damage mechanism, affinity against oxygen, reduction potential, decontamination efforts, endo-/exothermic reactions, diffusion properties related to finishes or bare materials, isothermal fatigue, thermo-cyclic fatigue, corrosion properties, lifetime prediction based on board level results, compatibility with rework/repair solders, rework temperatures of modified solders (Impurities, change in the melting point or range), compatibility to components and laminates.

• Korean Chemical Engineering Research
• /
• v.50 no.5
• /
• pp.759-765
• /
• 2012

As the biodiesel production is increasing rapidly, the crude glycerol, which is principal by-product of biodiesel production, has also been generated in a large amount. Many research studies on value-added utilization of glycerol are under investigation. 1,3-Propandiol is a promising chemical which can be produced from fermentation of glycerol because the application of 1,3-propanediol is mainly in the production of bio-PTT (Poly(trimethylene terephthalate). However, the cost of downstream processes in the biological production of 1,3-propanediol can make a high portion in the total production cost. This review summarizes the present state of separation processes in each step studied for the removal of impurities and the recovery of 1,3-propanediol from its fermentation broth. Furthermore, ATPE (Aqueous Two Phases Extraction) process is suggested as an attractive alternative for the primary separation process of 1,3-propanediol because ATPE is convenient for the simultaneous removal of microbial cells and impurities such as salts of organic acids and the separation of 1,3-propanediol from fermentation broth.

• Resources Recycling
• /
• v.19 no.4
• /
• pp.51-57
• /
• 2010

As a recycling of Si sludge from Si wafer process, a Si-SiC-CuO-C composite material was synthesized and investigated as an anode material for lithium batteries. The Si sludge consisted of Si, SiC, machine oil, and metallic impurities. The oil and metal impurities was removed by organic washing, magnetic separation, and acid washing. The Si-SiC-CuO-C composite from the recovered Si-SiC mixture was prepared by high-energy mechanical milling. According to the electrochemical tests such as charge-discharge capacity and cycling behavior, it showed the improved cycle performance. The SiC and CuO-related phases were presumed to restrain the volume expansion of the anode and Fe, however, should be removed below 10 ppm prior to synthesis of the composite because it caused the capacity loss of the active material itself.

• Environmental Engineering Research
• /
• v.20 no.1
• /
• pp.89-97
• /
• 2015

Remediation of wastewater contaminated with metal(II)-complexed species (Cu(II)-NTA (NTA: nitrilotriacetic acid), Cu(II)-EDTA (EDTA: ethylenediamine tetraacetic acid) and Cd(II)-EDTA is attempted using the potential applicability of ferrate(VI). Kinetics of pollutant degradation is obtained with the removal of ferrate(VI) studied at wide range of pH (8.0-10.0) and the concentration of metal(II)-complexed species (0.3 to 15.0 mmol/L) employing a constant dose of ferrate(VI) i.e., 1.0 mmol/L. Pseudo-first-order and pseudo-second-order rate constants were obtained in the reduction of ferrate(VI) which was then employed to obtain the overall rate constants of the pollutant degradation. The mineralization of NTA and EDTA was obtained with the change in TOC (total organic carbon) values collected by the ferrate(VI) treated pollutant samples. Decrease in pH and molar pollutant concentrations was greatly favored the percent mineralization of NTA or EDTA by the ferrate(VI) treatment. The treated pollutant samples were filtered and subjected for AAS (atomic absorption spectrophotometric) analysis to assess the simultaneous removal of copper and cadmium from aqueous solutions at the studied pH as well at the elevated pH 12.0. Results show that an enhanced removal of cadmium or copper was achieved at pH 12.0. Overall, ferrate(VI) possesses multifunctional application in wastewater treatment as it oxidizes the degradable impurities and removes metallic impurities by coagulation process.

• Journal of the Mineralogical Society of Korea
• /
• v.13 no.4
• /
• pp.171-185
• /
• 2000

Siliceous mudstones are embedded on a large scale in the Tertiary formations of Pohang area. Some useful zeolites such as NsP, (Na, TMA)P, analcime and hydroxysodalite were synthesized from the siliceous mudstones by treating with the variety of solution, i.e ., NaOH, NaOH+NaCl, NaOH, NaOH+$NaAlO_2$and NaOH+TMAOH at the low-temperature hydrothermal system ranging 60~12$0^{\circ}C$. Major precursor of zeolites is found as opal-CT in the zeolite-forming reaction. Smectite, which is included in considerable amounts in the mudstone, appears to play a major role of Al-source in the zeolite synthesis. In comparison, chalcedonic quartz and mica are rather insoluble in alkaline solution, and thus, these are observed as major impurities in the reaction products. An addition of $NaAlO_2$to NaOH solution is effective for eliminating these impurities in the reaction procedure, through these are partly dissolved when elevating the reaction temperature, concentration, and time. Phase change from NaP to hydroxysodalite takes place at the NaOH concentrations of 3.0~4.0 M, and the reaction is not sensitive to the temperature shift. NaP is more stable at lower NaOH concentration and higher activity of $Na_{+}$ whereas analcime is sensitive to the temperature change and stable at higher than $100^{\circ}C$ and 2.0~4.0 M in NaOH concentration. For the pure NaP synthesis without any other products, the treatment of mudstones with 1:1 solution of NaOH and $NaAlO _2$ turns out to be quite effective. NaP was successfully synthesized together with analcime at $100^{\circ}C$ as well as lower concentrations of NaOH+NaCl solution. In addition, the organic type, (Na, TMA)P was formed together with smectite in the 1:1 solution of NaOH and TMAOH.

• Journal of Korea Foundry Society
• /
• v.41 no.2
• /
• pp.139-143
• /
• 2021

A type of titanium alloy, ferro-titanium, is the main material used to manufacture steel and stainless steel. Considering economic aspects, ferro-titanium ingots are intended to be manufactured using low-cost titanium scrap, and the best pretreatment process for removing impurities from recycled titanium scrap surfaces was studied here. Instead of ordinary acid or organic solvents, ecofriendly methods were researched and applied, and chip scrap materials were used. A high-quality ferro-titanium ingot was manufactured from titanium scrap after a pretreatment process was applied, and the impurities and properties were analyzed and compared with commercial material standards through a component analysis.