• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1481-1489
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• 2002

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.633-635
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• 1999

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.391-394
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• 1997

A H$_{\infty}$ control techniques with roll eccentricity filter is proposed to alleviate the effect of entry thickness variation and roll eccentricity occurred in rolling stand itself of tandem cold mills. A robust controller to the disturbances is designed using H$_{\infty}$ control techniques, which can reflect the input direction of disturbances and knowledge of disturbance spectrum in the frequency domain. And, non-standard H$_{\infty}$ control problem caused by selection of weight function having poles on j.omega. axis is discussed. The evaluation for the resultant controller composed by H$_{\infty}$ synthesis is done through computer simulations. The effectiveness of the proposed method is compared to those of the conventional LQ synthesis method and a feedforward controller against roll eccentricity, which was already studied.ied.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1692-1696
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• 2014

A practical and efficient one-pot synthesis of 1,3,5-trisubstituted pyrazoles from ${\alpha},{\beta}$-enones and arylhydrazine hydrochlorides has been developed. The pyrazoles were formed via a tandem formation of the corresponding pyrazolines and an acid-catalyzed aerobic oxidation process.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.44-55
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• 2004

In order to meet the requirement for higher thickness accuracy in tandem cold rolling processes, it is strongly necessary to have good performance in control units. To meet this requirement, this paper suggested an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation and roll eccentricity simultaneously as the major disturbances, a synthesis of multivariable control systems was presented based on H$\infty$ control theory, which could reflect the knowledge of input direction and spectrum of disturbance signals on design. Then, to effectively reject roll eccentricity, a weight function having some poles on the imaginary axis was introduced. This lead to a non-standard H$\infty$ control problem, and the design procedures for solving this problem were analytically presented. The effectiveness of the proposed control method was evaluated through computer simulations and compared to that of the conventional linear quardratic control and feedforward control methods for roll eccentricity.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.341-344
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• 1999

The hydrazones of 2-acetylfuran, 2-acetylthiophene, and 2-acetylpyrrole, were allowed to react with S-methylthioacetimidate hydroiodide (8) to give azinoureas 10, and the reaction of 10 with Appel's dehydration conditions (triphenylphosphine/carbon tetrachloride/triethylamine) led to the corresponding azinocarbodiimides 11, which underwent thermal rearrangement under the reaction conditions to give 1,1-diheteroaryl ethylenes 13.

• Journal of Mechanical Science and Technology
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• v.18 no.1
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• pp.45-54
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• 2004

In order to meet the requirement for higher thickness accuracy in cold rolling processes, it is strongly desired to have high performance in control units. To meet this requirement, we have considered an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation as well as roll eccentricity as the major disturbances, a synthesis of multivariable control systems is presented based on H$\sub$$\infty$/ control theory, which can reflect the knowledge of input direction and spectrum of disturbance signals on the design. Then, to reject roll eccentricity effectively, a weight function having some poles on the imaginary axis is introduced. This leads to a non-standard H_ control problem, and the design procedures for solving this problem are analytically presented. The effectiveness of the proposed control method is evaluated through computer simulations and compared to that of the conventional LQ control and feedforward control methods for roll eccentricity.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.86-92
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• 2002

A short synthesis of novel prostanoids, 12-epi-carbacyclins 3 and 24, has been accomplished using palladium chemistry as a key step. The silyl enol ether 10a prepared through organopalladium chemistry has been allowed to react with 1-octen-3-one in the presence of $Pd(OAc)_2$ to give compound 12 in a single step. The unusual chemo- and stereoselective reduction of the ${\alpha},{\beta}$-unsaturated ketone in 12 has been effected with (S)-BINALH. Subsequent desilylation and Wittig reaction have provided the Subsequent desilylation and Wittig reaction have provided the $PGI_2$ analogues 3 and 24.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.575-578
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• 2005

Electrospray ionization mass spectrometry (ESI MS) was used, along with gas chromatography-mass spectrometry (GC-MS), to monitor Paal-Knorr synthesis of 2,5-dimethyl-1-phenylpyrrole by condensation of aniline with 2,5-hexanedione. In addition to 2,5-dimethyl-1-phenylpyrrole observed as a single spot by TLC, unexpected dimer size compounds were observed by GC-MS. Dimers and trimers were observed by ESI MS. ESI tandem mass spectrometry was used to select plausible structures for the dimer. ESI MS with or without liquid chromatographic separation is useful for observing oligomeric byproducts with low volatility produced in organic reactions.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.43-47
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• 2012

An efficient synthetic method for the preparation of quinolines through indium(III) chloride-catalyzed tandem addition-cyclization-oxidation reactions of imines with alkynes was developed. The processes can provide a diverse range of quinoline derivatives in good yields from simple imines and alkynes.