• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1377-1378
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• 2002

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.939-940
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• 2001

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1245-1247
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• 1997

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1384-1386
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• 1999

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.366-369
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• 2003

The vertical fountain plating system with the point contact has been used in semiconductor industry. But the plating shape in the opening of photoresist becomes gradated shape, because bubbles from the wafer surface are difficult to escape from the deep openings, vias. So, we designed the tilted electrode ring contact to get uniform bump height on all over the wafer and evaluated the film uniformity by SEM and $\alpha$-step. A photoresist was coated to a thickness of $60{\mu}m$ and vias were patterned by a contact aligner After via opening, solder layer was electroplated using the fountain plating system and the tilted electrode ring contact system. In $\alpha$-step measurement, film uniformities in the fountain plating system and the tilted electrode ring contact system were ${\pm}16%,\;{\pm}3.7%$ respectively. In this study, we could get high uniformity bumps by the tilted electrode ring contact system. So, tilted electrode ring contact system is expected to improve workability and yield in module process.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1433-1436
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• 1999

The 2-(2,4-dimethoxyphenyl)-4-MDO (2) underwent polymerization with ring opening as well as cyclization reaction in the presence of various cationic catalysts such as boron trifluoride, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid and trifluoroacetic acid. They afforded a mixture of the ring-opened poly(keto ether) and 3(2H)-dihydrofuranone derivative. Both the methylene group and oxygen atom of 1,3-dioxolane ring were participated in the reaction with cationic catalyst. The contents of the polymer and cyclization product were variable according to the acid strength of the cationic catalysts.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.793-795
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• 1998

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.64-69
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• 1991

A lipid containing a 1, 2-dithiolane group was synthesized, and polymerized vesicle was prepared from the vesicle of this lipid by ring-opening polymerization. Reaction rate of the polymerization was monitored by UV absorption, and the results showed that it followed the first order kinetics and the rate constant $3.84{\times}10^{-2}min^{-1}$. Permeation rate of sucrose through the polymerized vesicle was $4.7{\times}10^{-8}cm\;hr^{-1}$, which is 1.5 times lower than that of monomeric analog.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.199-199
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• 2006

Microwave-irradiation has become a common heat source in organic chemistry in the last decade. In recent years, polymer chemists also discovered the advances of microwave heating that include fast and efficient heating as well as the homogeneous heat profile and the easy access to pressurized reaction conditions. In this contribution, we report our investigations on the cationic ring-opening polymerization of 2-oxazolines that lead to a tremendous acceleration from several days to several minutes polymerization time. In addition, the optimized microwave-assisted polymerization procedure was applied for the preparation of libraries of diblock and triblock copolymers that were used for the determination of structure-property relationships in poly(2-oxazoline)s.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.104-105
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• 2006

We succeeded the synthesis of new functional polymers by novel ring-opening addition reactions of bis(oxetane)s with diacyl chlorides, di(active ester)s, and di(carboxylic acid)s using quaternary onium salts as catalysts at appropriate conditions. Hyperbranched polyesters with many pendant hydroxy groups were also synthesized by the polyaddition of bis(oxetane)s with tricarboxylic acid, or by the self-polyadditions of $AB_2\;or\;A_2B$ type monomers containing oxetane group. The anionic ring-opening polymerization of (3-ethyl-3-hydroxymethyl)oxetane was examined using sodium tert-buthoxide to give hyperbranched poly(ether)s containing one oxetanyl group and many hydroxyl groups in the end of polymer chain.