• 한국재료학회지
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• 제21권5호
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• pp.283-287
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• 2011

As the performance of microelectronic devices is improved, the use of copper as a heat dissipation member is increasing due to its good thermal conductivity. The high thermal conductivity of copper, however, leads to difficulties in the joining process. Satisfactory bonding with copper is known to be difficult, especially if high shear and peel strengths are desired. The primary reason is that a copper oxide layer develops rapidly and is weakly attached to the base metal under typical conditions. Thus, when a clean copper substrate is bonded, the initial strength of the joint is high, but upon environmental exposure, an oxide layer may develop, which will reduce the durability of the joint. In this study, an epoxy adhesive formulation was investigated to improve the strength and reliability of a copper to copper joint. Epoxy hardeners such as anhydride, dihydrazide, and dicyandiamide and catalysts such as triphenylphosphine and imidazole were added to an epoxy resin mixture of DGEBA and DGEBF. Differential scanning calorimetry (DSC) analyses revealed that the curing temperatures were dependent on the type of hardener rather than on the catalyst, and higher heat of curing resulted in a higher Tg. The reliability of the copper joint against a high temperature and high humidity environment was found to be the lowest in the case of dihydrazide addition. This is attributed to its high water permeability, which led to the formation of a weak boundary layer of copper oxide. It was also found that dicyandiamide provided the highest initial joint strength and reliability while anhydride yielded intermediate performance between dicyandiamide and dihydrazide.

• Molecules and Cells
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• 제37권2호
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• pp.100-108
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• 2014

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu,Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages.

• Journal of Preventive Medicine and Public Health
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• 제22권4호
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• pp.518-527
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• 1989

The relationship between copper content in scalp hair and mental retardation was investigated. Samples of scalp hair were collected from 297 mentally retarded children who were students in one of two schools providing special educational services, one, consisted of children living in an orphan home, the other, children living with parents. For comparison, 117 scalp hair samples were collected from the children who had got average or above average academic achivement in a regular elementary school. Hair samples were taken from the nape of the neck and the copper content was determined by an atomic absorption spectrophotometer (IL 551). There was no statistically significant difference in scalp copper levels across different age groups except female orphan group, but no trend or correlation between copper conents and age was found. The hair copper contents of the mentally retarded children groups were significantly lower than that of control groups. But there was no dose-response relationship between degree of mental retardation and hair copper level. The hair copper contents of the group accompanied by Down's syndrome and unknown group were significantly lower than that of control group in both sex, and in the case of accompanied by epilepsy or autism, lower than control group in male. Although the results of this study show no evidence that mental retardation has owed to copper deficiency, the possibility of copper deficiciency in their fetal or infant age could not be ruled out. Thus further study is needed to determine whether mental retardation could be attributed to copper deficiency, through the examinations about their living environments, dietary pattern, eating habit and the impact of copper deficiency on brain development.

• 한국환경농학회지
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• 제16권1호
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• pp.48-54
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• 1997

구리 내성균인 P. stutzeri의 균체내 구리 축적 특성, 축적형태 및 균체내에 축적된 구리의 회수 방법을 조사한 결과는 다음과 같다. 구리 농도가 100mg/l인 용액중에서 치리 48시간 후 구리 내성균주의 구리 처리율은 약 78% 이상이었다. 구리가 축적된 균체를 전자현미경으로 관찰한 결과, 균체의 cell wall과 cell membrane에 많은 electron-dense granule들이 형성되어 있었으며, electron-dense granule들은 EDS로 분석한 결과, 이 granule들은 copper complex인 것으로 확인되었다. 구리 내성균주의 균체내 축적된 구리는 증류수에 의해서는 거의 탈착이 되지 않았으나 EDTA 처리에 의해서는 약 80% 이상 탈착되었다. 구리가 축적된 균체를 $550^{\circ}C$에서 회화시켰을 때 건조균체량의 약 23.2%에 해당하는 작열잔류화합물들이 생성되었으며, 이 작열잔류화합물들은 EDS로 분석한 결과, 구리가 약 78.4% 이상 함유되어 있는 비교적 순수한 구리 화합물인 것으로 확인되었다.

• 보존과학회지
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• 제36권3호
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• pp.162-177
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• 2020

부여 관북리 유적에서 시행된 동 생산 및 제련과정을 살펴보기 위하여 '나'지구, '라'지구 출토동 생산 부산물(동 슬래그 및 동 도가니) 11점의 과학적 분석을 시행하였다. 분석방법은 파장분산형 X-선 형광 분석, X-선 회절 분석, 금속 현미경 관찰, 주사 전자현미경-에너지 분산형 X-선 분석기, 전계방출 전자탐침미량분석기, 라만 마이크로분광분석법을 사용하였다. 분석결과 관북리 동 슬래그에서는 주로 도가니 슬래그 및 정련 슬래그에서 전형적인 특징으로 나타나는 규산염 광물, Magnetite, Fayalite, Delafossite 등이 검출되었다. 또한 관북리 동 슬래그는 외형 및 미세조직의 양상의 특성에 따라 1. 유리질 바탕 기지 + Cu prill, 2. 유리질 바탕 기지 + Cu prill + Magnetite, 3. 규산염 광물 바탕 기지 + Cu prill, 4. 결정질(Delafossite, Magnetite)/유리질(비정질) 바탕 기지 + Cu prill, 5. Magnetite + Fayalite, 6. 청동합금 슬래그로 분류되었다. 미세조직 내에는 SiO₂, Al₂O₃, CaO, SO₄ P₂O₅, Ag₂O, Sb₂O₃ 등의 불순물이 잔재되어 있으며, 일부는 주석과 납이 합금되어 있는 것을 확인하였다. 이와 같은 결과를 통해 부여 관북리 유적에서는 동 생산과정 중 배소와 제련을 거친 동 중간생성물의 정련과 불순물이 함유된 동-주석, 또는 동-주석-납의 합금정련을 시행하였다고 판단된다.

• 자원리싸이클링
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• 제27권6호
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• pp.44-52
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• 2018

본 연구에서는 동 함유 슬러지로부터 회수된 동 조금속을 황산구리 전해액에서 전해정련 공정 조건을 선택적으로 조절함에 따라 초미세 분말 형태의 동을 회수하고자 하였다. 황산구리 전해액 농도, 인가전류밀도, 첨가제 종류 및 농도에 따라 LSV(Linear Sweep Voltammetry)을 이용하여 초미세 분말 제조가 가능한 인가전류밀도 범위를 설정하여 전해정련 공정을 수행 하였다. 이 때 얻어진 분말에 대해 SEM(Scanning Electron Microscope) 및 PSA(Particle Size Analyzer)를 사용하여 동 분말 형상 및 크기를 분석하였다. 유기첨가제를 사용하지 않은 0.1 ~ 0.4 M 황산구리 전해액 조건에서 동 분말 크기는 인가전류밀도가 한계전류밀도에 가까울수록 감소하였고, 0.2 ~ 0.3 M 황산구리 전해액에서 동 분말 크기가 가장 감소하는 경향을 나타내었다. 또한, 위 실험을 통해 얻은 공정 조건을 바탕으로 유기 첨가제 종류 및 농도를 달리 첨가하여 동 분말 표면 형상 및 크기를 분석하였을 때, Cellulose계 첨가제 2,000 ppm 조건에서 가장 작은 크기(nm급)의 양호한 구형 형태 동 분말을 얻을 수 있었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.435-437
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• 2002

Polishing of copper, a process called copper chemical mechanical polishing, is a critical, intermediate step in the planarization of silicon wafers. During polishing, the electrodeposited copper films are removed by slurries: and the differential polishing rates between copper and the surrounding silicon dioxide leads to a greater removal of the copper. The differential polishing develops dimples and furrows; and the process is called dishing and erosion. In this work, we present the results of experiments on dishing and erosion of copper-CMP, using patterned silicon wafers. Results are analyzed for the pattern factors and properties of the copper layers. Three types of pads - plain, perforated, and grooved - were used for polishing. The effect of slurry chemistries and pad soaking is also reported.

• Asian-Australasian Journal of Animal Sciences
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• 제9권4호
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• pp.359-362
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• 1996

A study was conducted to assess the influence of copper on the total sulphur amino acid requirements of broiler chickens reared under two growing periods. The TSAA levels used were 0.73, 0.83, 0.93% with copper levels of 0, 125, 250 and 375 mg/kg for the starter period and the TSAA levels of 0.72, 0.79 and 0.86% with copper levels of 0, 125, 250 and 375 mg/kg for the grower period. Total feed consumption, body weight gain and feed L gain ratio were used as the parameters for the assessment. The results showed that adding copper at 250 mg/kg to the diets improved feed : gain ratio of the starter broilers and resulted in small improvement of body weight gain and feed : gain ratio of the grower broilers. Growth was depressed in relation to the reduction of feed intake on the chicks fed diet containing 375 mg/kg copper. There was a significant interaction between dietary TSAA and copper levels for feed intake, hence, indicating that the supplementation of copper at the level of 375 mg/kg increased the TSAA requirement of the starter broilers, although no interference with the requirement of grower broilers.

• Asian-Australasian Journal of Animal Sciences
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• 제12권4호
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• pp.548-553
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• 1999

An experiment was conducted to study the effects of high dietary copper supplementation on the gastrointestinal tract morphology of broiler chickens. Eighty 3-week-old broiler chicks were divided randomly into eight groups of four dietary treatments and over three week were fed isoenergetic and isonitrogenous diets that contained 0, 100, 250, or 500 mg/kg of supplemental copper from cupric sulfate. The copper supplementation in the broiler diet up to 250 mg/kg did not significantly influence broilers' performance. A high dietary copper supplementation of 500 mg/kg did significantly depress growth and feed conversion in the broilers (p<0.05). Copper supplementation more than 250 mg/kg in the broiler diet significantly influenced the morphology of the GI tract, as shown by severe oral lesions and gizzard erosion. It also significantly depressed the villi height and significantly thickened the muscular layer in the duodenum (p<0.05). The severely damaged villi were observed by scanning electronic microscope from the duodenum samples of broilers fed a 500 mg/kg copper supplemented diet. The 500 mg/kg copper supplemented diet also significantly influenced the plasma constituents. Plasma glucose concentration was significantly depressed (p<0.05).

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.194.1-194.1
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• 2016

The present study investigated the effect of zincate treatment time on the dissolution behavior and the deposition of copper by immersion process and electroplating process on AZ31 Mg alloy substrate in a copper pyrophosphate bath. Without zincate pretreatment, the AZ31 Mg substrate quickly dissolved in the copper pyrophosphate solution although an external cathodic current was applied. The copper layers deposited on non-zincate treated AZ31 Mg alloy substrate by both immersion and electroplating processes showed very porous structure and very poor adhesion. With increasing zincate treatment time up to 2 min, the dissolution of AZ31 substrate in pyrophosphate solution rapidly decreased and the deposited copper layer was less porous and exhibited stronger adhesion. The immersion of AZ31 Mg sample in zincate solution for 5 min was found as a critical time for producing a non-porous and adherent electrodeposited copper layer on AZ31 Mg alloy. The optimum zincating time can be determined by observing the open circuit potential (OCP) of AZ31 Mg alloy samples in a copper pyrophosphate electroplating bath. The OCP reached a stable value of about -0.10 V (vs. SCE) after 5 min of immersion in the copper pyrophosphate electroplating solution.