• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.236.2-236.2
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• 2015

The copper-zinc(Cu-Zn) nanofiber was prepared by electrospinning method. The Cu/PVP (polyvinylpyrrolidone) and Zn/PVP precursor solutions were prepared by dissolution of copper sulfate and zinc acetate in methanol, respectively. The PVP was used to control the viscosity of the precursor solutions. The optimized ratio for the Cu/PVP and Zn/PVP nanofibers was determined separately. Then the suitable ratio of the precursor solutions was applied for fabrication of Cu/Zn/PVP nanofiber. For the electrospinning method, the precursor solutions were filled in a syringe. The distance between metallic needle on the syringe and collector was fixed at 16 cm and the voltage was applied on the tip was 13.0 kV. And the as-spun nanofiber was heated at 353K for removal of residual solvent. Then the heated nanofibers were calcined at 973K to decompose PVP. The obtained Cu, Zn, and Cu-Zn nanofibers were investigated with X-ray photoelectron spectroscopy (XPS) for the chemical properties, scanning electron microscopy (SEM) for the morphologies, and X-ray diffraction (XRD) to characterize the crystallinity and phase of nanofibers.

• 한국의류학회지
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• 제27권7호
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• pp.843-850
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• 2003

Cu/PET film composites were prepared by electroless copper plating method. In order to improve adhesion between electroless plated Cu layer and polyester (PET) film, the effect of pretreatment conditions such as etching method, mixed catalyst composition were investigated. Chemical etching and plasma treatment increased surface roughness in decreasing order of Ar＞HCl＞O$_2$＞NH$_3$. However, adhesion of Cu layer on PET film increased in the following order: $O_2$＜Ar＜HCl＜NH$_3$. It indicated that appropriate surface roughness and introduction of affinitive functional group with Pd were key factors of improving adhesion of Cu layer. PET film was more finely etched by HCI tolution, resulting in an improvement in adhesion between Cu layer and PET film. Plasma treatment with NH$_3$produced nitrogen atoms on PET film, which enhances chemisorption of Pd$^{2+}$ on PET film, resulting in improved adhesion and shielding effectiveness of Cu layer deposited on the Pd catalyzed surface. Surface morphology of Cu plated PET film revealed that Pd/Sn colloidal particles became more evenly distributed in the smaller size by increasing the molar ratio of PdCl$_2$; SnCl$_2$from 1 : 4 to 1 : 16. With increasing the molar ratio of mixed catalyst, adhesion and shielding effectiveness of Cu plated PET film were increased.d.

• 한국주조공학회지
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• 제24권6호
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• pp.331-339
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• 2004

Melt-extrusion process, a metallic melt poured and solidified up to semisolid state in the container can be directly extruded through the die exit to form a product of bar shape without other intermediate processes. In this study, the fabrication characteristics of the process were evaluated with various process parameters, such as preheating temperature of extrusion dies, extrusion temperature and extrusion ratio. AI-Cu alloys were successfully extruded after squeezing out of liquid during melt-extrusion with smaller force compared to the solid extrusion. Soundly AI-Cu alloy bar was fabricated at the preheating temperature of $500{\sim}520^{\circ}C$. The range of extrusion temperature for soundly melt-extruded AI-Cu alloy bar was increased with increasing extrusion ratio. Mechanical properties of melt-extruded AI-Cu alloy bars were found change with Cu content of the melt-extruded bars due to the occurrence of segregation. The various extrusion temperature yielded equiaxed structure with a grains size about 200 ${\mu}m$.

• 한국자기학회지
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• 제8권5호
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• pp.282-287
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• 1998

유리 기판위에 dc magnetron sputtering 방법으로 제작한Fe(50 $\AA$)/[Co(17 $\AA$)/Cu(24 $\AA$)]20 다층박막에 관하여 자기저항비의 기저층, 자성층, 비자성층의 증착률 및 열처리 의존성을 살펴보았다. 낮은 base 압력 중에서의 막의 증착은 Co/Cu 계면의 산화를 억제하여 자기저항비를 장가시켰다. 극대 자기저항비를 얻기위해 요구되는 증착률은 Fe는 1$\AA$)/s 이상, Cu는 2.8 $\AA$)/s 이었으며 Co는 증착률이 2 $\AA$/s 보다 높은 경우에 평탄한 자구형성을 이루어 자기적 향비가 높아지는 경향을 보였다. 40$0^{\circ}C$까지의 시료에 대한 역처리는 다층박막의 주기성을 유지한채 더 큰 결정립을 형성시켜 반강자성적으로 결합한 막의 부분이 증가함으로써 자기저항비를 증가시켰다.

• 자원리싸이클링
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• 제26권4호
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• pp.95-100
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• 2017

본 연구에서는 폐 PCB(printed circuit board) 표면을 긁어내어 회수한 구리분말을 용융하는 과정에서 용융온도 저감과 정제를 위하여 플럭스로 $Fe_2O_3$를 첨가하였으며, $Fe_2O_3$ 첨가량 및 온도에 따른 구리의 회수율과 불순물 농도에 미치는 영향을 조사하였다. 구리 회수율은 반응온도와 $Fe_2O_3$의 첨가비율이 증가할 수 록 증가하였다. 그리고 구리 중 산소, 실리콘, 철의 농도는 $Fe_2O_3$ 첨가량이 증가할수록 감소하였다. $Fe_2O_3$를 첨가하여 반응시킨 후의 슬래그를 XRD로 분석하여 fayalite($2FeO{\cdot}SiO_2$)와 철산화물을 확인하였다. 따라서 fayalite 슬래그의 생성에 의한 슬래그의 융점과 점도 감소가 구리 회수율의 증가에 크게 기여한 것으로 생각된다.

• Progress in Superconductivity
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• 제13권1호
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• pp.7-11
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• 2011

조성경사법을 이용하여 LMO/IBAD-MgO template 상에 EDDC 증착법을 이용하여 $Sm_{1+x}Ba_{2-x}Cu_{3+y}O_{7-d}$ 초전도 박막을 증착하였다. 테이프 형상의 기판상에 길이방향으로 $Sm_{1+x}Ba_{2-x}Cu_{3+y}O_{7-d}$ 박막의 조성비가 연속적으로 변하는 샘플을 얻을 수 있었고, 비접촉 Hallprobe를 이용하여 임계전류를 측정한 결과 조성비에 대응하는 연속적인 임계전류분포를 측정할 수 있었다. 본 조성비 영역 중 Sm:Ba:Cu = 1.01:1.99 :4.87의 조성비에서 최대의 임계전류를 보였다. 이 조성비에서 SmBCO 박막표면에 전체적으로 roof tile 형상의 결정립들이 관찰되었으며 국소적으로 2차상들이 관찰되었다. 조성 경사법을 이용하면 광범위한 조성비영역에서 신뢰도 높은 초전도특성, 결정배향성, 박막표면 형상 등을 조사할 수 있을 것으로 예상된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1993년도 춘계학술발표회
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• pp.35-36
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• 1993

• 한국재료학회:학술대회논문집
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• 한국재료학회 1994년도 춘계 학술발표 강연 및 논문 개요집
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• pp.35-35
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• 1994

• 한국수소및신에너지학회논문집
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• 제15권3호
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• pp.201-207
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• 2004

Redox characteristics of metal oxide for hydrogen production by thermochemical water-splitting were investigated. $CuFe_2O_4$ as a redox pair that had a different molar ratio of Cu and Fe were prepared by co-precipitation method. Hydrogen production consisted of water-splitting step and thermal reduction step was performed below 1200K. Redox characteristics of Cu-ferrites were studied using the thermal gravimetric analysis technique. Also, structure change of Cu-ferrite during thermal reduction was investigated using the high temperature controlled XRD. In results, oxygen release of Cu-ferrite during the thermal reduction was initiated at oxygen site combined with Cu. Consequently, oxygen release amount of Cu-ferrite was increased with increase of Cu molar ratio of Cu-ferrite. It was found that thermal reduction of Cu-ferrite was begun at $875^\circ{C}$. It was confirmed that structure of Cu-ferrite was changed to metal and cation excess metal oxide during the thermal reduction step.

• Transactions on Electrical and Electronic Materials
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• 제4권1호
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• pp.7-10
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• 2003

Single phase CuInS$_2$ thin film with the strongest diffraction peak (112) at diffraction angle (2$\theta$) of 27.7$^{\circ}$ and the second strongest diffraction peak (220) at diffraction angle (2$\theta$) of 46.25$^{\circ}$was well made with chalcopyrite structure at substrate temperature of 70$^{\circ}C$. annealing temperature of 250$^{\circ}C$, annealing time of 60 min. The CuInS$_2$ thin film had the greatest grain size of 1.2 Um when the Cu/In composition ratio of 1.03, where the lattice constant of a and c were 5.60${\AA}$ and 11.12${\AA}$, respectively. The Cu/In stoichiometry of the single-phase CuInS$_2$thin films was from 0.84 to 1.3. The film was p-type when tile Cu/In ratio was above 0.99 and was n-type when the Cu/In was below 0.95. The fundamental absorption wavelength, absorption coefficient and optical band gap of p-type CuInS$_2$ thin film with Cu/In=1.3 were 837nm, 3.OH 104 cm-1 and 1.48 eV, respectively. The fundamental absorption wavelength absorption coefficient and optical energy band gap of n-type CuInS$_2$ thin film with Cu/In=0.84 were 821 nm, 6.0${\times}$10$^4$cm$\^$-1/ and 1.51 eV, respectively.