• 보존과학연구
• /
• s.6
• /
• pp.121-196
• /
• 1985

Atomic absorption spectrophotometer was used for analyzing each 10elements(Cu, Pb, Sn, Zn, Sb, Fe, Ni, Ag, Co and Mn)on 64 Chinese coinsre covered from Shinan seabed sunken ship. The results show that Cu, Pb and Sn were found to be a major elements consisting of coins and its composition ratio was 6 to 2 to 1.The composition of trace elements on coins was classified 3 levels : Sb, Fe and Zn(0.02%-2.2%), Ag, Ni, and Co(50 ppm-5500 ppm) and Mn(Trace). Theam ount of major elements, Cu and Sn were decreased while increased in Pbby the passage of ages (10th - 13th century) in China. There seems to be no systematic compositional change in major elements but content in trace elements was confirmed to increase with age.

• Korean Journal of Materials Research
• /
• v.9 no.10
• /
• pp.1018-1024
• /
• 1999

The effects of operating temperature and stress on degradation of components in high temperature steam generator were investigated. Several 2.25CrlMo tubes which had operated over 20 years and an unused 9CrlMoVNb tube were tested. For the former samples, the amount of $\textrm{M}_{6}\textrm{C}$ carbide and its size are increased with the aging or operating time. The precipitation behavior of carbides ($\textrm{M}_{2}\textrm{O}$, $\textrm{M}_{6}\textrm{C}$) is changed with the operating temperature of the tubes. However, unused 9CrlMoVNb samples show a different carbide precipitation process due to high chromium, vanadium, and niobium contents. The amount of Cr-rich $\textrm{M}_{23}\textrm{C}_{6}$ carbide is significantly increased with aging time, but that of $\textrm{M}_{6}\textrm{C}$ type carbide is rarely changed with aging time at elevated temperatures.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.181.2-181.2
• /
• 2016

OLED 소자는 발광 방향에 따라 Bottom Emission 방식과 Top Emission 방식으로 나뉜다. 이 중 대면적 OLED TV 적용에 개구율이 더 높은 Top Emission방식을 선호하는 추세이다. 높은 개구율을 가진 Top Emission OLED소자를 위해서는 투명하고 전도성이 높은 캐소드가 중요하다. 본 연구에서는 Themal Evaporation 시스템을 이용하여 증착한 $SnO_2/Ag-Pd-Cu(APC)/SnO_2$ hybrid 전극의 특성을 연구하고 Oxide/Metal/Oxide(OMO) hybrid 박막의 bending mechanism을 제시하였다. base pressure는 $1{\times}10^{-6}Torr$로 고정하고 $SnO_2$ 박막은 0.34A / 0.32V, APC 박막은 0.46A / 0.40V의 power로 성막하였다. APC와 $SnO_2$의 두께를 변수로 OMO 전극을 제작하였고 그 전기적, 광학적 특성을 Hall measurement, UV/Visible spectroscopy을 이용하여 분석하고 Figure of merit 값을 바탕으로 최적 두께를 설정하였다. UPS(Ultraviolet Photoelectron Spectroscopy) 분석으로 $SnO_2/APC/SnO_2$ 전극의 일함수을 통해 투명 cathode로 쓰였을 때 $SnO_2$ 층이 buffer layer역할을 함을 확인하였다. XPS(X-ray photoelectron spectroscopy)를 이용하여 정성분석과 정량분석을 하였고 OMO hybrid 전극의 bending mechanism 연구를 위해 다양한 bending test (Inner/Outer dynamic fatigue test, twisting test, rolling test)를 진행하였다. 물리적 힘이 가해진 OMO hybrid 전극의 표면과 구조는 FE-SEM(Field Emission Scanning Electron Microscope) 분석을 통해서 확인할 수 있었다.

• 보존과학연구
• /
• s.10
• /
• pp.1-40
• /
• 1989

Between 1976 and 1984 approximately 26.7 tons of Chinese coins were recovered from a shipwreck which was found at the seabed of the Shin an area in the south-western coast of the Korean peninsula. Elements, Cu, Pb, Sn, Fe, Sb, As, Zn, Ag, Ni, Co and Mn, of 54 pieces of the coins were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy(ICP-AIS). The result shows that Ch, Pb, and Sn were found to be major elements roughly the coins with the ratio of 7 : 2 : 1, respectively. Trace elements were classified into 3 levels according to the avarage concentration : Fe,As and Sb(0.1-0.5%), Ag, Mi, Co and Zn(100-1000ppm) and Mn(10ppm). Some systematic tendencies are observed in the composition change with a function of their minting ages .The Wuzhu coins(오수전) from the Eastern Han dynasty(A.D.25-219 )are much more abundant in Cu than the coins of Tang dynasty(A.D.618-907) and later periods. Major element compositions of the Kai -tong Vuan-Bao(개통원보) coins from the Tang dynasty, were remarkably variable. In general, however, the Tang dynasty coins were much more abundant in Cu than the Song dynasty(A.S.S60-1279) coins. The amount of major elements Cu and Sn decreases while that of Pb in creasesby passage of age from the Bei Song dynasty(A.D.960-1127) to later Nam Song dynasty (A.D.1127-1279 ). It means that the quality of coins mere degraded. The amounts of trace elemends(Fe, As, Co, Hn) increases with the above age. High amounts of trace elements are supposed to be a reflection of immaturity of minting techniques or use of impurity-rich raw materials. The Jin dynasty(A.D.1125-1234) coins are found to be rich in Sn and thus contain Pb as the third component. It is quite different from the coins of the Song dynasty. The Zhi-dai Tong-Bao(지대통보) coins of the Yuan dynasty from A.0.1310 are much more abundant in Cu and Sn than those of the Nam Song dynasty .

• The Korean Journal of Mycology
• /
• v.15 no.3
• /
• pp.175-182
• /
• 1987

A raw starch saccharifying enzyme from Aspergillus sp. SN-871 was purified by ammonium sulfate precipitation, DEAE-cellulose column chromatography, CM-Sephadex C-50 column chromatography and Sephadex G-75 gel filtration. The specific activity of purified enzyme was 18 fold and the yeild was 13.40%. The molecular weight of the purified enzyme was estimated as approximately 40,000 dalton by the method of Andrews gel filtration. The optimum pH and temperature for this enzyme were found to be 4 and $40^{\circ}C$, respectively and the stable range of pH was 2 to 5. The enzyme was themostable at below $60^{\circ}C$ and inactivated at $70^{\circ}C$. It showed a tendency to increase the enzyme activity under the presence of 0.01 M $BaCl_2$, but under 0.01 M$Pb(NO_3)_2$, $AgSO_4$, and $K_3Fe(CN)_6$ and citric acid etc. inhibited it completely. The substrate specifity of enzyme showed a tendency to increase the enzyme activity under addition of dextrin and glycogen, but under saccharose inhibited it. COD removal rate of Aspergillus sp. SN-871 was approximately 67 to 68%.

• Conservation Science in Museum
• /
• v.10
• /
• pp.1-13
• /
• 2009

A part of the bronze bell from Goryeo (918-1392) in the collection of Buyeo National Museum was missing, and it was noted to retain corrosion products and burial accretions. Chemical analysis showed that the chemical composition of the bronze bell is Cu (74.18%), Sn (9.58%), Pb (15.77%), and very small amounts of As, Fe, Sb, Bi, and Ag. It was noted that the microstructure of the bronze bell was mainly made up of α phase and α+δ eutectoid phase, and gray (S) and black (Pb segregation) prevailed. Conservation treatment has been done for the preservation of this bronze bell.

• Journal of the Korean Chemical Society
• /
• v.15 no.2
• /
• pp.49-54
• /
• 1971

It is shown that the impurities of Cu(II), Pb(II), Zn(II) and Ag(I) in Bismuth metal and the components of Pb(II), Zn(II) and Sn(IV) in Bismuth alloy are separated into their components from each other by elutions through $3.14cm^2{\times}10cm$ cation exchange resin, $Dowex\;50w\;{\times}\;8$ (100~200 mesh), column with the mixed solutions of HAc and NaAc as the eluents. The elution curve of Fe(III) has a long tailing and is not separated quantitatively from Bi(III). The eluents used for this separation are as follows; 1M HAc + 0.1M NaAc (pH 3.36) for Fe(III) and Bi (III). 0.3M HAc + 0.3M NaAc (pH 4.70) for Cu(II), Pb(II) and Zn(II). 0.5M HAc + 0.5M NaAc (pH4.70) for Ag(I) and Sn(IV). The analysis of cations eluted are carried out by spectrophotometry and EDTA titrimetry. Their recoveries are more than 99%.

• Journal of Conservation Science
• /
• v.17 s.17
• /
• pp.33-38
• /
• 2005

One piece of Haedong-Tongue(해동통보) minted at 1,102 A.D. was excavated from No.20 wooden coffin, Sinbong-dong, Cheongju. It was analyzed by micro-XRF and ICP and determined the concentrations of ten elements such as Cu, Pb, Sn, Zn, Fe, Mn, Sb, Co, As, Ag and Ni. The measurement of lead isotope ratios was also carried out in order to predict the provenance of raw materials used for minting of Haedong-Tongbo. It was found that Haedong-Tongbo was minted with three compositions of $Cu\;75.5\%,\;Pb\;13.3\%\;and\;Sn\;6.0\%$, which were different from the typical composition of Chosen-Tongbo and Sangpyung-Tongbo used in Chosen dynasty. Lead isotope ratios of Haedong-Tongbo showed that the provenance of lead used for minting of it suggested the possibility to be originated from Southern part of Korea.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2000.11a
• /
• pp.57-57
• /
• 2000

Brazing characteristics of the LTCC(Low Temperature Co-fired Ceramics)/ Kovar(Fe-Ni-Co alloy) was investigated. Kovar is one of the typical material for the lid of MCM and packages. In case of alumina package, Brazing process is done by higher temperature profile than 800 $^{\circ}C$ and Ag-Cu alloy. But, LTCC has sintering temperature near 850 $^{\circ}C$. So, it is difficult to use the same process as alumina brazing. The adhesion strength of the brazed part is affected by brazing alloy and metallization properties between conductor pattern and LTCC material. We investigated brazing characteristics of the LTCC/Kovar using various brazing alloys(Ag-Cu, Au-Sn) and process conditions. And, we examined the influence of the glass contents in conductor on the brazing characteristics of the LTCC/Kovar.

• Clean Technology
• /
• v.11 no.3
• /
• pp.153-164
• /
• 2005

This study found a reliable evaluation for four kinds of pb-Free plating solutions and it's layers, through pure Sn, SnAg, SnBi and SnCu. These four kind of solutions are widely used to pb-Free plating. Hull-cell, Harring-blum, coverage, throwing power, current efficiency, stability, life-time, composition, hardness, roughness, abrasion, scratch, solderability, corrosion, contact angle, morphology, SIR(Surface insulation resistance) and Whisker test were experimented. Also, Using ICP, XRF, FE-SEM, EDS, temperature/humidity chamber, solderability tester, hardness tester, roughness tester, abrasion tester, salt spray tester, contact angle tester, SIR tester, and microscope. In this paper could be shown the systematic and various analysis for reliability about four kinds of pb-Free plating solutions, processes and it's deposit surface.