• 한국전기화학회:학술대회논문집
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• 2004.04a
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• pp.5-5
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• 2004

• Journal of Powder Materials
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• v.12 no.4 s.51
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• pp.255-260
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• 2005

Direct solid state synthesis by hot pressing has been applied in order to produce high efficiency $Zn_4Sb_3$ bulk specimens. Single phase $Zn_4Sb_3$ with 98.5% of theoretical density was successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by direct synthesis were measured and are comparable to the published data. Direct solid state synthesis by hot pressing provides a promising processing route in this material.

• Bulletin of the Korean Chemical Society
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• v.21 no.6
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• pp.562-566
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• 2000

$\beta-D-Mannopyranosyl$ disaccharides have been obtained from the coupling of 4,6-O-benzylidene derivatives of ethylthio $\alpha-D-mannopyranoside$ employing NIS-TfOH promoter. NIS-TfOH promoted couplings of the corresponding ethylthio $\beta-D-glucopyranoside$ and produced $\alpha-D-glucopyranosyl$ disaccharides. IDCP (iodonium dicollidine perchlorate) was inactive toward the 4,6-O-benzylidenated ethylthio glucopyranosyl donor. However,lDCP coupled the 4,6-O-benzylidenated $ethylthio-\beta-D-galactopyranoside$ to give a-D-galactopyranosyl disaccharides.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3692-3695
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• 2011

Poly(N,N'-Dichloro-N-ethyl-benzene-1,3-disulfonamide) (PCBS) and N,N,N',N'-Tetrachlorobenzene-1,3-disulfonamide (TCBDA) were found to be a mild and efficient reagent for the direct oxidative conversion of sulfur compounds to the corresponding arenesulfonyl chlorides in good to excellent yields through the oxidative chlorination. The overall process is simple, practical, and it provides convenient access to a variety of aryl or heteroarylsulfonyl chlorides. The mild reaction conditions and the broad substrate scope render this method attractive, and complementary to existing syntheses of aryl or heteroarylsulfonyl chlorides.

• Journal of the Korean Society for Heat Treatment
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• v.8 no.3
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• pp.187-196
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• 1995

TiN and AlN are ceramic materials with mechanical and chemical properties for use in structural applications at elevated temperature. The purpose of this research is to develop the technology for the synthesis of (Ti, Al)N power, which shows simultancously the excellent properties of TiN and AlN, from the mixed powder($Ti_{0.25}Al_{0.75}$, $Ti_{0.5}Al_{0.5}$ and $Ti_{0.75}Al_{0.25}$) by the direct nitriding method. The effects of variables such as temperature, mixing ratio of Al to Ti in raw material were investigated. The(Ti, Al)N powder can be easily synthesized from the mixed powder by the direct nitriding method. Among the mixed powdres, the nitriding behavior decreased with increasing the ratio of Al to Ti. This behavior is well explained by the nitriding mechanism presented in this research.

• Journal of Integrative Natural Science
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• v.10 no.4
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• pp.175-191
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• 2017

In organic chemistry amide synthesis is performed through condensation of a carboxylic acid and an amine with releasing one equivalent of water via the corresponding ammonium carboxylate salt. This method is suffering from tedious processes and poor atom-economy due to the adverse thermodynamics of the equilibrium and the high activation barrier for direct coupling of a carboxylic acid and an amine. Most of the chemical approaches to amides formations have been therefore being developed, they are mainly focused on secondary amides. Direct carbonylations of tertiary amines to amides have been an exotic field unresolved, in particular direct carbonylation of trimethylamine in lack of commercial need has been attracted much interests due to the versatile product of N,N-dimethylacetamide in chemical industries and the activation of robust N-C($sp^3$) bond in tertiary amine academically. This review is focused mainly on carbonylation of trimethylamine as one of the typical tertiary amines by transition metals of cobalt, rhodium, platinum, and palladium including the role of methyl iodide as a promoter, the intermediate formation of acyl iodide, the coordination ability of trimethylamine to transition metal catalysts, and any possibility of CO insertion into the bond of Me-N in trimethylamine. In addition reactions of acyl halides as an activated form of acetic acid with amines are reviewed in brief since acyl iodide is suggested as a critical intermediate in those carbonylations of trimethylamine.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1233-1240
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• 2014

For the last three decades after the advent of the Toffoli gate in 1980, while many reversible circuit syntheses have been presented reversible embedding methods onto suitable reversible functions, only a few proposed direct irreversible-to-reversible mapping methods without reversible embedding. In this paper we present two effective policies to reduce the gate cost and complexity for the existing direct reversible mapping methods without reversible embedding. In order to develop new cost reduction policies we consider the cost influence of Toffoli module according to NOT gate arrangement in classical circuits. From this we deduced an inverse proportional property between inverting input numbers of classical AND/OR gates and reversible Toffoli module cost based on a fact - the inverting inputs of classical AND(OR) gates increase(decrease) the Toffoli module cost. We confirm the applications of the inverting input rearrangement and maximum fan-out policies preceding direct reversible mapping will be effective method to improve the reversible Toffoli module cost and complexity with the parallel using of the fan-out and supercell ones.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.377-377
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• 2006

Alkoxyamine and thiocarbonyl thio end capped polyethylene (PE) chains were synthesized using a direct and simple approach consisting in reacting di(polyethylenyl)magnesium (PE-Mg-PE) chains with a range of nitroxides and disulfides of thiocarbonyl thio compounds. PE-Mg-PE compounds were prepared by a catalyzed chain growth reaction of ethylene on nbutyloctylmagnesium (BOMg) with a neodymocene complex $(C_{5}Me_{5})_{2}NdCl_{2}Li(OEt_{2})_{2}$. Complete characterizations confirm the introduction of the desired end groups. The controlled radical polymerization (NMP and RAFT) of butyl acrylate mediated by these functional polyethylenes was successful.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.732-739
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• 1993

Good yields were usually obtained in Pd(O)-catalyzed Suzuki aryl-aryl coupling reaction, even when both coupling partners had an ortho tertiary benzamide functional group. The direct ortho functionalization of oligomeric tertiary benzamides at Snieckus condition is dependent on the chain length. Tertiary benzamide 1 can be o,o-dilithiated only by metal-halogen exchange of the 2,6-dihalo-compound. Bis-tertiary benzamide 9 can be o,o'-dilithiated with excess(4.1 equivalents) s-butyllithium/TMEDA as the lithiating agent. Tris-tertiary benzamide 21 is hard to o,o"-difunctionalize due to steric interactions among the tertiary benzamide functional groups, and due to steric interactions between these functional groups and others (if present) on the termini of the terphenyl unit.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.215-223
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• 2005

Current interest in the regioselective N-functionalization of tetraazacycloalkanes (cyclen and cyclam) stems mainly from their complexes with radioactive metals for applications in diagnostic ($^{64}Cu,\;^{111}In,\;^{67}Ga$) and therapeutic ($^{90}Y$) medicine, and with paramagnetic ions for magnetic resonance imaging ($Gd^{+3}$). Selective methods for the N-substitution of cyclen and cyclam is a crucial step in most syntheses of cyclen and cyclam-based radiometal complexes and bifunctional chelating agents. In addition, mixing different pendent groups to give hetero-substituted cyclen derivatives would be advantageous in many applications for fine-tuning the compound's physical properties. So far, numerous approaches for the regioselective N-substitution of tetraazacycloalkanes and more specifically cyclen and cyclam are reported. Unfortunately, none of them are general and every strategy has its own strong points and drawbacks. Herein, we categorize numerous regioselective N-alkylation methods into three strategies, such as 1) direct substitution of the macrocycle, 2) introductiou of the functional groups prior to cyclization, and 3) protection/iunclionallrationideproteclion. Our discussion is also split into the methods of mono- and tri-functionalization and di-functionalizataion based on number of substituents. At the end, we describe new trials for the new macrocycles which iorm more stable metal complexes with various radiometals, and briefly mention the commercially available tetraazacycloalkanes which are used for the biconjugation of biomolecules.