• The Science & Technology
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• v.31 no.4 s.347
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• pp.72-74
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• 1998

중국 명나라 말기인 1637년에 과학자 송응성은 중국의 전통기술서 천공개물을 펴냈다 3부로 구성된 이 책은 1부에서 곡물 .의복 등을 2부에서 기와, 용기. 화포. 제련. 석회 등 제조기술을 ,그리고 3부에서는 금 .구리 등 금속기술과 무기 제조 .보석 등을 다뤘다.1771년 일본에서 따로 간행된 이 책은 19세기부터 서양에도 소개되기 시작했으며 이번엔 국내에서 우리말로 번역되어 출간되었다.

• Resources Recycling
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• v.26 no.1
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• pp.30-36
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• 2017

Leaching experiments of anode slime were performed with several inorganic acids (HCl, $HNO_3$ and $H_2SO_4$) together with thiourea and thiosulfate solution to recover gold and silver. Gold was not dissolved at all into these inorganic acids in the absence of any oxidizing agents. At the same concentration of inorganic acid, the leaching of percentage of Ag was the highest in the sulfuric acid solution. The leaching percentage of silver increased with the increase of HCl concentration owing to the formation of $AgCl_2{^-}$. Copper, nickel and zinc except tin was almost dissolved in these inorganic acids but no tin was dissolved in nitric acid solution. Most of Au and Ag were dissolved into the mixture of sulfuric acid and thiourea solution. Thiosulfate could dissolve some silver from the anode slime but no gold was dissolved by this agent.

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.315-324
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• 2003

In this study, a new method is presented to produce stable hydrophobic metal alloy nanocluster in chloroform solution including surfactant NaAOT(sodium bis(2-ethylhexyl)-sulfosuccinate) via the chemical reduction of metal salt $(HAuCl_4,\AgNO_3,\Cu(NO_3)_2)$ by sodium borohydride. For the alloy nanocluster, several samples were prepared by changing the molar ratio of Au/Cu, Au/Ag alloy nanocluster, 3:1, 1:1, 1:3. The alloy nanoclusters were characterized by UV-Visible spectrophotometer, TEM(Transmission Electron Microscope), and XPS(X-ray Photoelectron Spectrometer). With the change of the mole ratio of the alloy component, the wavelengths of the surface plasmon absorption shift linearly from 520 nm of the pure Au nanocluster to 570 nm of the pure Cu nanocluster for Au/Cu alloy nanoclusters and from 405 nm to 520 nm for Au/Ag alloy nanoclusters. The chemical shifts of the Au4f, Ag3d, Cu2p XPS peaks were observed with changing the molar ratio of the alloy element. The alloy nanoclusters in chloroform solution were made uniformly in size and colloidally stable for long periods of time. These results indicate that the method here is a very effective method for synthesizing hydrophobic alloy nanoclusters with uniform or nearly uniform particle size distribution.

• Conservation Science in Museum
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• v.17
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• pp.1-16
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• 2016

The gold buckle excavated from Seogam-ri Tomb No. 9(National Treasure No. 189), one of the oldest gold artifacts discovered within the Korean Peninsula, was created using granulation techniques. The buckle is made with 22.8K gold sheets and features a decorative design with seven dragons in repousse metalwork. The outlines of the dragons and the edge of the buckle are finished with 23.8K gold wires and granules. Some curved sections of the buckle are also covered with an extra sheet of 23.8K gold, possibly added to repair defects discovered during production or thereafter. Gold wire used to render the dragon's nostrils is slightly lower in purity(23.3K) and was probably preferred in this case due to its increased hardness. As a result, the metal is better able to retain the complex shape of the dragons' nostrils, created by rolling gold wire into spirals. The buckle's gold granules are found in small, medium and large sizes and are presumed to have been bonded using copper. The foreheads and the bodies of the seven dragons are inset with turquoise and the eyes are decorated with red cinnabar/vermillion(HgS).

• Korean journal of applied entomology
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• v.48 no.2
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• pp.269-274
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• 2009

Rearing media were selected for the production of sterile larvae of greenbottle blowfly, Phaenicia (=Lucilia) sericata (Meigen) which is widely used in maggot therapy. Eight media available in the market were used in this study. Egg hatchability was not different among the media. Survivorship of the larvae was higher in blood agar (BA), sabouraud dextrose agar, and brucella blood agar than the others. A higher content (20${\sim}$40%) of sheep blood in BA and chocolate agar increased the survivorship of larvae. The eggs and the early 3rd larvae could be stored for 12 days at $8^{\circ}C$ and for 15 days at $6^{\circ}C$ without decrease in hatchability and larval survivorship, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.141-141
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• 1999

전기화학과 초고진공(ultra-high vacuum, UHV) 분광법을 이용하여 고체/액체의 계면에서 일어나는 현상을 분자단위에서 이해하고 조절하기 위한 연구를 수행하였다. 이들 중 전기화학으로 형성된 구리 및 은 금속(sub)monlayer 박막을 그 예로 선택하여 소개한다. 초박막 금속의 흡착량은 cyclic voltammogram과 새로 개발된 Auger electron spectroscopy (AES) 정량법을 통해 얻어졌고, 이 값들은 low energy electron diffraction (LEED) 및 in-situ atomic force microscopy (AFM)법을 이용한 구조 분석결과와 비교되어졌다. 또한 화학상태를 확인하기 위하여 core-level electron energyy loss spectroscopy (CEELS)를 사용하였다. 먼저 황산 전해질에서 금(111) 단결정 전극상에 전기화학적으로 형성된 굴의 계면특성을 조사하였다. 특정 전위값에서 2/3 ML의 구리와 1/3 ML의 음이온이 상호 흡착하여 ({{{{ SQRT { 3} }}$\times${{{{ SQRT { 3} }}) 격자 구조를 보였고, 전위값이 커지거나 줄어들면, 이 구조가 사라지는 현상이 관찰되었다. 즉 이 ({{{{ SQRT { 3} }}}}$\times${{{{ SQRT { 3} }}}}) 흡착구조는 첫 번째 UPD underpotential deposition) 피크에 특이하게 관련되어 있음을 알 수 있었다. 금속 초박막 형성에 미치는 음이온의 영향을 좀 더 확인하기 위해 초박막 은이 증착된 금 단결정 전극상의 황산 음이온에 관하여 연구하였다. 은의 증착이 일어날 수 없는 양전위값 영역에서 ({{{{ SQRT { 3} }}}}$\times${{{{ SQRT { 3} }}}})의 규칙적인 음이온의 구조를 보였다. 그리고 은의 장착은 세척 과정과 용액의 농도에 따라 p(3$\times$3)과 p(5$\times$5)의 규칙적인 두가지 구조를 가졌다. in-situ AFM에서는 p(3$\times$3)의 은 증착 구조만 나타났고, 음 전위값으로 옮겨가면 p(1$\times$1) 구조로 바뀌었다. ex-situ 초고진공 결과와 이 AFM의 in-situ 결과를 상호 비교 논의할 것이다. 음이온의 흡착이 없는 묽은 플로르산(HF) 전해질에서 은은 전위값을 음전위 쪽으로 이동해 감에 따라 p(3$\times$3), p(5$\times$5), (5$\times$5), (6$\times$6), 그리고 (1$\times$1)의 연속적 구조 변화를 보였다. 이 다양한 구조들을 AES로부터 얻어진 표면 흡착량과 연결시켰더니 정량적으로 잘 일치되는 결과를 보였다. 전기화학적인 증착에서는 기존의 진공 증착과 비교할 때 음이온의 공흡착이 금속 초박막 형성 메카니즘에 큰 영향을 미침을 알 수 있었다. 또한 은의 전기화학적 다층박막 성장은 MSM (monolayer-simultaneous-multilayer) 메카니즘을 따름을 확인하였다. 마지막으로 구조 및 양이 규칙적으로 조절되는 전극의 응용가능성이 간단히 논의될 것이다.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.7-11
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• 2003

The semiconductor chips or electronic components generate heat, which causes malfunction of the parts when it was not cooled properly. Bulky heat sink and cooling fan are used to get rid of the heat. However, with this bulky system, it is hard to integrate the electronics system in a small scale. The cooling efficiency of the system depends on the surface area of the heat sink, thermal conductivity of the material and the method of integration. In order to develop a novel cooling system, a micro-heatsink with a large surface area while retaining small volume was fabricated by electroless deposition of gold/copper inside a Track-etched membrane. The structure of the micro-heatsink was investigated using SEM or optical microscope. It was also found that the micro-heatsink is more efficient than a flat copper plate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.410-413
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• 2003

We have developed the measurement system for the high power laser The absorber is made of gold-plated copper cavity. The calibration heater is using a manganin(CuMn12Ni ; Isabellenhutte) coil, and output power is measured by using of resistance bridge with composed manganin and copper coil. Developed system can measure for 5∼1000w laser output power range. Calibration factors are 489.13 J/mV at 100W range and 489.13 J/mV at 500W range. Correction factors are 0.99 at 100W range and 1.006 at 500W range.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1799-1804
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• 2005

We have developed and estimated the measurement system of $CO_2$ and Nd:YAG laser power of wide range. The absorber is made of gold-plated copper cavity. The calibration heater is using a manganin(CuMn12Ni) coil, and output power is measured by using or resistance bridge with composed manganin and copper coil. Developed system can measure 5${\~}$1000W laser output power range. Calibration factors are 489.13J/mV at 100W and 497.04(J/mV) at 500W. correction factors are 0.99 at 100W and 1.006 at 500W.

• Analytical Science and Technology
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• v.14 no.6
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• pp.516-521
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• 2001

This research was for reducing leachated concentration of hazardous pollutants in bottom ash from municipal solid waste combustors(200 tons/day) of Korea. Lead and copper compounds were selected as main pollutants. For reducing of leachated level, optimal conditions were observed using air oxidation for lead compounds and water washing method for copper compounds. and it was observed stable pH range of bottom ash from analyzing lechated level by pH variation.