• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.35-44
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• 1998

All the triacylglycerols including the molecular species having ${\Delta}^5$-unsaturated fatty acids from the seeds of Pinus Koraiensis, were split into a mixture of diacylglycerols by a Grignard reagent prepared with allyl bromide without arousing acyl chains of a glycerol moiety to migration, and were also easily partially hydrolyzed to diacylglycerols by pancreatic lipase. (S)-(+)-(1-naphthyl)ethyl urethane(NEU) derivatives of the diacylglycerol mixture derived from the triacylglycerols were fractionated into sn-1, 3-, sn-1, 2- and sn-2, 3-DG-NEU by silica-HPLC and the fatty acid composition of these fractions was analysed. $C_{18:1{\omega}9}$ is distributed evenly in the three positions of TG with $C_{18:2{\omega}6}$ mainly located in sn-2 position, while ${\Delta}^5$-unsaturated fatty acids such as ${\Delta}^{5.9}-C_{18:2}$, ${\Delta}^{5.9.12}-C_{18:3}$ and ${\Delta}^{5.11.14}-C_{20:3}$ are exclusively present in the sn-3 position. These results could be confirmed by $^{13}C$-NMR spectroscopy : the signals at $^{\delta}$173.231 ppm and $^{\delta}$172.811 ppm of the carbonyl carbon of acyl moieties indicate the presence of saturated acids and/or $C_{18:1{\omega}9}$ (oleic acid) in the ${\alpha}({\alpha}')$- or ${\beta}$- positions, and $C_{18:2{\omega}6}$ including $C_{18:1{\omega}9}$ in the ${\beta}$-position, respectively. In addition, the resonance at $^{\delta}$173.044 ppm suggested a location of ${\Delta}^5$-unsaturated fatty acid moiety in the ${\alpha}({\alpha}')$-position.

• Journal of the Korean institute of surface engineering
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• v.22 no.4
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• pp.168-178
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• 1989

The compositions and microstructures of Pb-Sn alloy electrodeposits were investigated in terms of the electrolysis conditions conditions by using fluoborate bath. The Pb content of alloy deposit decreased with increasing dreasing current density until the limting content was obtained. The proferred orientation of Pb-phase in the alloy changed in the sequence of (110)longrightarrow(100)longrightarrow(100)+(110)(311)longrightarrowrandom distribution of crystals with increasing cathode overpotential, while that of $\beta$-Sn phase was (110)(301)(211)n mixed texture. The smooth surface with granular crystallites was obtained below medium current desity, while the rough surface texture was formed at high current density.

• Journal of Korea Foundry Society
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• v.21 no.4
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• pp.239-245
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• 2001

Microstructure and mechanical properties of Sn-3.1 wt.%Ag-6.9 wt.%Bi system solders on Cu-substrate were studied. The Sn3.1 wt.%Ag-6.9 wt.%Bi alloy was designed by phase diagram and chemical properties and was prepared by melting in argon atmosphere. The mechanical properties of solder/Cu joints were examined by shear strength test, and also creep test. The microstructure of Sn-3.1 wt.%Ag-6.9 wt.%Bi alloy consists of Bi-rich phase and $Ag_3Sn$ precipitate in {\beta}-Sn$ matrix phase. The shear strength of the joint was decreased with aging treatment. Crack path under shear test was through the solder. Similar crack path change mode was observed at the creep test of solder/Cu joint. The creep behavior of Sn-3.1 wt.%Ag-6.9 wt.%Bi alloy represented the inverse primary creep behavior at all test condition. It is suggested that the inverse primary creep behavior is induced from Bi solute atoms in Sn-matrix. The creep resistance of Sn-3.1Ag-6.9Bi alloy is better than that of Sn-3.5 wt.%Ag alloy at all test conditions.

• BMB Reports
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• v.34 no.5
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• pp.457-462
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• 2001

Using the monomolecular film technique, we compared the interfacial properties of Staphylococcus simulans lipase (SSL) and Staphylococcus aureus lipase (SAL). These two enzymes act specifically on glycerides without any detectable phospholipase activity when using various phospholipids. Our results show that the maximum rate of racemic dicaprin (rac-dicaprin) hydrolysis was displayed at pH 8.5, or 6.5 with Staphylococcus simulans lipase or Staphylococcus aureus lipase, respectively The two enzymes interact strongly with egg-phosphatidyl choline (egg-PC) monomolecular films, evidenced by a critical surface pressure value of around $23\;mN{\cdot}m^{-1}$. In contrast to pancreatic lipases, $\beta$-lactoglobulin, a tensioactive protein, failed to inhibit Staphylococcus simulans lipase and Staphylococcus aureus lipase. A kinetic study on the surface pressure dependency, stereoselectivity, and regioselectivity of Staphylococcus simulans lipase and Staphylococcus aureus lipase was performed using optically pure stereoisomers of diglycerides (1,2-sn-dicaprin and 2,3-sn-dicaprin) and a prochiral isomer (1,3-sn-dicaprin) that were spread as monomolecular films at the air-water interface. Both staphylococcal lipases acted preferentially on distal carboxylic ester groups of the diglyceride isomer (1,3-sn-dicaprin). Furthermore, Staphylococcus simulans lipase was found to be markedly stereoselective for the sn-3 position of the 2,3-sn-dicaprin isomer.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.1
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• pp.2-9
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• 2004

This study has examined the metallurgical microstructures and alloy compositions of 3 bronze artifacts, a vessel, a spoon and a chopstick, manufactured in the Koryo Dynasty. The results show that they were made from Cu-Sn alloys whose Sn content ranges from 22 to 24% by weight. It is of significant importance to find that they were all given special thermo-mechanical treatments during their manufacturing. It has been found that the Koryo bronze workers were well aware of the mechanical properties of ${\alpha}$, ${\beta}$, ${\gamma}$ and ${\delta}$ phases that appear in the Cu-Sn alloys. Knowing how to promote or suppress the formation of each phase, they were able to find proper alloy compositions and temperatures for the high Sn alloys to be successfully forged. The present study will detail the Koryo bronze technology as estimated from the microstructures of the 3 bronze artifacts. The results of the reproduction experiments with Cu-24%Sn will also be presented to explain how the microstructures develop and to estimate the mechanical properties of each phase.

• Korean Journal of Metals and Materials
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• v.49 no.1
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• pp.17-24
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• 2011

To investigate the relationship between heat treatment in zirconium alloy tubing process and metallurgical characteristics of Zr-1Nb-0.69Sn-0.11Fe alloy tubes, mechanical and oxidation behaviors of tubes heat treated at different temperatures after the final pilgering were investigated. The stress strain curves exhibited the saturation behaviors in all heat treatment conditions ($460{\sim}600^{\circ}C$) in this study with the onset strain of saturation increased with increase of post-pilgering annealing temperature. The strength fell off rapidly with increasing annealing temperature. The ultimate strength of the low tin Zr-1Nb-0.69Sn-0.11Fe alloy with slightly higher iron and oxygen contents in this study was found to be higher than Zr-1Nb-1Sn-0.1Fe alloy. The oxidation experiments in steam condition revealed that the corrosion resistance of low tin Zr-1Nb-0.69Sn-0.11Fe alloy was better than the Zr-1Nb-1Sn-0.1Fe alloy with a higher Sn content. The weight gain of low tin Zr-1Nb-0.69Sn-0.11Fe alloy tubes gradually increased with the increasing annealing temperature possibly due to the decreased Nb content in the matrix because of the formation of ${\beta}-Nb$ particles.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.450-455
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• 2002

Cu-cored Sn-Ag solder balls were fabricated by coating pure Sn and Ag on Cu balls. The melting behavior and the solderability of the BGA joint with the Ni/Au coated Cu pad were investigated and were compared with those of the commercial Sn-Ag and Sn-Ag-Cu balls. DSC analyses clarified the melting of Cu-cored solders to start at a rather low temperature, the eutectic temperature of Sn-Ag-Cu. It was ascribed to the diffusion of Cu and Ag into Sn plating during the heating process. After reflow soldering the microstructures of the solder and of the interfacial layer between the solder and the Cu pad were analyzed with SEM and EPMA. By EDX analysis, formation of a eutectic microstructure composing of $\beta$-Sn, Ag$_3$Sn, ad Cu$_{6}$Sn$_{5}$ phases was confirmed in the solder, and the η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer was found to form at the interface between the solder and the Cu pad. By conducting shear tests, it was found that the BGA joint using Cu-cored solder ball could prevent the degradation of joint strength during aging at 423K because of the slower growth me of η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer formed at the solder, pad interface. Furthermore, Cu-cored multi-component Sn-Ag-Bi balls were fabricated by sequentially coating the binary Sn-Ag and Sn-Bi solders on Cu balls. The reflow property of these solder balls was investigated. Melting of these solder balls was clarified to start at the almost same temperature as that of Sn-2Ag-0.75Cu-3Bi solder. A microstructure composing of (Sn), Ag$_3$Sn, Bi and Cu$_{6}$Sn$_{5}$ phases was found to form in the solder ball, and a reaction layer containing primarily η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ was found at the interface with Ni/Au coated Cu pad after reflow soldering. By conducting shear test, it was found that the BGA joints using this Cu-core solder balls hardly degraded their joint shear strength during aging at 423K due to the slower growth rate of the η'-(Au, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer at the solder/pad interface.he solder/pad interface.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.4
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• pp.1-27
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• 2001

이 글의 목적은 독일어 신체어휘 관련 관용구들 가운데 ${\lceil}$Duden Band 11${\rfloor}$에 수록된 108개의 $\lceil$손$\rfloor$ 관련 관용구를 대상으로 이들의 형태$\cdot$통사구조를 파악하고, 그들을 모형화하는 것이다. 우리는 연구 대상을 문장에서 결합가 보유어로서 술어의 기능을 하는 관용구에 한정했다. 우리는 $\lceil$손$\rfloor$ 관련 관용구를 보충어의 수와 형태에 따라 크게 세 가지 부류, 즉 1가, 2가, 3가의 관용구로 구분하였다 보충어의 형태는 명사구(Sn, Sd, Sa)와 전치사구(pS)에 한정했으며 문장형태의 보충어, 예를 들어 부문장(NS)과 부정사문(Inf) 형태는 고려하지 않았다. 이들이 보충어로 간주될 수 있는지의 여부는 아직 더 많은 연구를 필요로 하기 때문에 다음 과제로 남겨두었다. 일차적으로 외적 결합가($\"{a}u{\beta}ere\;Valenz)$에 따라, 이차적으로는 내적 결합가(innere Valenz)에 따라 108개의 $\lceil$손$\rfloor$ 관련 관용구를 분석한 결과 우리는 다음과 같은 형태$\cdot$통사적 문형을 얻을 수 있었다. $\cdot$ 1가 동사 관용구: 1) PL-Sn : (1) PL[VPL - Sa] - Sn (2) PL(VPL - pS) - Sn (3) PL[VPL - Sa - pS] - Sn (4) PL[VPL - pS - pS] - Sn Sondergruppen: PL[VPL - Sa - Inf] - Sn PL[VPL - pS - Inf] - Sn 2) PL - Sd: (1) PL[VPL - Sn] - Sd (2) PL[VPL - Sn(es) - pS] - Sd $\cdot$ 2가 동사 관용구1) PL - Sn - Sd: (1) PL[VPL - Sa] - Sn - Sd (2) PL[VPL - pS] - Sn - Sd (3) PL[VPL - Sa - pS) - Sn - Sd 2) PL - Sn - pS: (1) PL[VPL - Sa] - Sn - pS (2) PL[VPL - pS] - Sn - pS (3) PL(VPL - Sa - pS) - Sn - pS 3) PL[VPL - pS) - Sn -Sa $\cdot$ 3가 동사 관용구: (1) PL[VPL - pS] - Sn - Sd - Sa (2) PL[VPL - pS] - Sn - Sa - pS (3) PL[VPL - Sa] - Sn - Sd - pS 이러한 분류가 보여주듯이, 독일어에는 1가, 2가, 3가의 관용구가 있으며, 구조 외적으로 동일한 통사적 결합가를 갖는다 하더라도 구조 내적 성분구조가 다르다는 것을 알 수 있다. 우리는 이 글이 외국어로서의 독일어를 배우는 이들에게 독일어의 관용구를 보다 올바르게 이해할 수 있는 방법론적인 토대를 제공함은 물론, (관용어) 사전에서 외국인 학습자를 고려하여 관용구를 알기 쉽게 기술하는 데 도움을 줄 수 있기를 바란다.

• Journal of Technologic Dentistry
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• v.23 no.1
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• pp.55-64
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• 2001

This study is focusing on the improvement of problems of Ti-6Al-4V alloy. A new Ti based alloy, Ti-15Sn-4Nb, have designed to examine any possibility of improving the mechanical properties and biocompatibility. Specimens of Ti alloys were melted in vacuum arc furnace and homogenized at $100^{\circ}C$ for 24h. All specimens were solution treated at $812^{\circ}C$ and aged at $500^{\circ}C$ for 10h. The corrosion resistance of Ti alloys was evaluated by potentiodynamic polarization test and immersion test inl%Lactic acid solutions. Ti-15Sn-4Nb system alloys showed Widmanstatten microstructure after solution treatment which is typical microstructure of ${\alpha}+{\beta}$ type Ti alloys. Analysing the corrosion resistance of Ti alloys, it was concluded that the passive films of Ti-15Sn-4Nb system alloys are more stable than that of Ti-6Al-4V alloys. Also, the corrosion resistance of Ti-15Sn-4Nb system alloys was improved with adding elements, Hf. It was analysed that the passive film of the Ti-15Sn-4Nb alloy which was formed in air atmosphere was consisted of TiO2, SnO and NbO through X-ray photoelectron spectroscopy(XPS) analysis.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.60-64
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• 2008

The aerial parts of Spathiphyllum cannifolium were extracted with 80% aqueous MeOH and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_2O$, successively. From the EtOAc fraction, three compounds were isolated through the repeated silica gel, ODS, Sephadex LH-20 column chromatographies. From the results of physico-chemical data including NMR, MS and IR, the chemical structures of the compounds were determined as stigmasterol (1), $(2S)1-O-linolenoyl-2-0-myristoyl-3-0-{\beta}-D-galactopyranosyl-sn-glycerol$ (2) and stigmasterol glucoside (3). They were the first to be isolated from Spathiphyllum cannifolium.