• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.914-917
• /
• 2005

The paper proposes a new sonic resonance test for a dynamic elastic constant measurement which is based on time-average electronic speckle pattern interferometry(TA-ESPI)and Euler-Bernoulli equation. Previous measurement technique of dynamic elastic constant has the limitation of application for thin film or polymer material because contact to specimen affects the result. TA-ESPI has been developed as a non-contact optical measurement technique which can visualize resonance vibration mode shapes with whole-field. The maximum vibration amplitude at each vibration mode shape is a clue to find the resonance frequencies. The dynamic elastic constant of test material can be easily estimated from Euler-Bernoulli equation using the measured resonance frequencies. The TA-ESPI dynamic elastic constant measurement technique is able to give high accurate elastic modulus of materials through a simple experiment and analysis.

• Korean Journal of Materials Research
• /
• v.30 no.4
• /
• pp.160-168
• /
• 2020

The current density in copper electroplating is directly related with the productivity; then, to increase the productivity, an increase in current density is required. This study is based on an analysis of changes in surface characteristics and mechanical properties by applying the addition of Alcian Blue (AB, C₅₆H₆₈Cl₄CuN₁₆S₄). The amount of Alcian Blue in the electrolytes is changed from 0 to 100 ppm. When Alcian Blue is added at 20 ppm, a seed layer is formed homogeneously on the surface at the initial stage of nucleation. However, crystals electroplated in electrolytes with more than 40 ppm of Alcian Blue are observed to have growth in the vertical direction on the surface and the shapes are like pyramids. This tendency of initial nucleation formation causes protrusions when the thickness of copper foil is 12 ㎛. Thereafter, a lot of extrusions are observed on the group of 100 ppm Alcian Blue. Tensile strength of groups with added Alcian Blue increased by more than 140% compare to no-addition group, but elongation is reduced. These results are due to the decrease of crystal size and changes of prior crystal growth plane from (111) and (200) to (220) due to Alcian Blue.

• Progress in Medical Physics
• /
• v.22 no.2
• /
• pp.85-91
• /
• 2011

The energy spectra for electron beam of medical linear accelerator were calculated using a GEANT4 Medical Linac 2 example code. The incident electron mean energy were 6, 9, 12, 16, 20 MeV. This code was designed to calculate electron beam energy spectra according to material, thickness and location of electron scattering foil affecting electron beam characteristic. Lead, Copper, Aluminum and Gold were used for scattering foil. The energy distribution for electron and photon were analyzed by changing position of scattering foil in the head of linear accelerator. The effect of electron scattering foil on energy spectra which is basic data of simulation for medical linear accelerator were presented. The calculated results would be used in design of medical accelerator head.

• Journal of Surface Science and Engineering
• /
• v.51 no.4
• /
• pp.191-196
• /
• 2018

The self-annealing which leads evolution of microstructure in copper electroplating layers at room temperature occurs after forming deposition layer. During the process, crystal orientation, size and sheet resistance of plating layer change. Lastly, it causes the change of physical and mechanical characteristics such as a tensile strength of plating layer. In this study, the variation of incorporated impurities, microstructure and sheet resistance of copper plating layer formed by electroplating are measured with and without inorganic additives during the self-annealing. In case of absence of inorganic additives, the copper layer presents strong total intensity of incorporated impurities. During the self-annealing, such width of reduction was significant. Moreover, microstructure and crystal size are increased while the tensile strength is decreased noticeably. On the other hand, in the presence of inorganic additives, there is no observable distinction in the copper plating layer. According to the observation on movements of the incorporated impurities in electrodeposition copper layer, within 12 hours the impurities are continuously shifted from inside of the plating layer to its surface after as-deposited electroplating. Within 24 hours, except for the small portion of surface layer, it is considered that most of the microstructure is transformed.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2003.11a
• /
• pp.174-176
• /
• 2003

유기첨가제 첨가법을 통해 개발된 저조도 전해동박을 전자파 차폐용 필터로 적용하기 위해서는 시인성을 확보하기 위한 흑화표면처리가 요구된다. 이를 위해 검토된 흑화표면처리 방법 중 흑화도, 전도성, 치수안정성 공정성에 있어서 전기도금법이 가장 우수한 것으로 나타났다. 개발된 흑화도금액계는 흑색도금조직을 $0,2{\mu}m$이하로 미세하게 노듈화시킴으로 인해 외부 빛을 산란시켜 광택을 줄이고 흑화도를 증가시켰으며 전착된 흑화도금층의 묻어남을 최소화할 수 있는 조성으로 구성되었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2014.11a
• /
• pp.122-122
• /
• 2014

본 연구에서는 micro-hardening을 통한 고강도 고연성 전해동박을 제조하기 위해 Sn, Co, Zn 등의 원소 첨가량, 전류밀도, 전해액 온도, 첨가제 제어 등의 공정조건 변화에 따른 전해동박층의 표면 형상, 조성 및 전기전도도를 평가하였고, 인장강도와 연신율을 평가하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2014.11a
• /
• pp.60-60
• /
• 2014

By the pre-doping technique on graphene/copper foil, we obtained the pristine sheet resistance and optical transmittance of the chlorine doped-single layer graphene $245{\Omega}/sq$ and 97% at 550 nm wavelength, respectively. X-ray photoelectron spectroscopy revealed that an extremely high Cl coverage of 47.3% of monolayer graphene surface was achieved as the highest surface-coverage graphene doping material ever reported.

• Korean Journal of Metals and Materials
• /
• v.48 no.10
• /
• pp.951-956
• /
• 2010

This study examined the effect of copper and sulfuric acid concentrations on the surface morphology and physical properties of copper plated on a polyimide (PI) film. Electrochemical experiments with SEM and a four-point probe were performed to characterize the morphology and mechanical characteristics of copper electrodeposited in the composition of an electrolyte. The resistivity and peel strength were controlled using a range of electrolyte compositions. A lower resistivity and high flexibility were obtained when an electrolyte with 20 g/l of copper was used. However, a uniform surface was obtained when a high current density that exceeded $20mA/cm^2$ was applied, which was maintained at copper concentrations exceeding 40 g/l. Increasing sulfuric acid to >150 g/l decreased the peel strength and flexibility. The lowest resistivity and fine adhesion were detected at a $Cu^{2+}:H_2SO_4$ ratio of 50:100 g/l.

• Polymer(Korea)
• /
• v.34 no.1
• /
• pp.84-87
• /
• 2010

Copper-indium-diselenide (CIS) particles were prepared by the electrochemical reduction from the mixture solution of corresponding ion compounds. The prepared CIS was used as an insertion layer or a blending component in the organic photovoltaic bulk heterojunction cells composed of poly(3-octylthiophene) and fullerene. The increase of CIS content resulted in the rapid decrease of the open-circuit voltage as well as short-circuit current. The photovoltaic parameters were analyzed in relation to the structures, composition, and morphology of the photovoltaic blends.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.141-141
• /
• 2018

Copper is one of the most abundant metals on earth. Its oxide (CuO) is an intrinsically p-type metal-oxide semiconductor with a bandgap ($E_g$) of 1.2-2.0 eV 1. Copper oxide nanomaterials are considered as promising materials for a wide range of applications e.g., lithium ion batteries, dye-sensitized solar cells, photocatalytic hydrogen production, photodetectors, and biogas sensors 2-7. Recently, high-density and uniform CuO nanostructures have been grown on Cu foils in alkaline solutions 3. In 2011, T. Soejima et al. proposed a facile process for the oxidation synthesis of CuO nanobelt arrays using $NH_3-H_2O_2$ aqueous solution 8. In 2017, G. Kaur et al. synthesized CuO nanostructures by treating Cu foils in $NH_4OH$ at room temperature for different treatment times 9. The surface treatment of Cu in alkaline aqueous solutions is a potential method for the mass fabrication of CuO nanostructures with high uniformity and density. It is interesting to compare the gas sensing properties among CuO nanomaterials synthesized by this approach and by others. Nevertheless, none of above studies investigated the gas sensing properties of as-synthesized CuO nanomaterials. In this study, CuO nanowalls versus nanoparticles were synthesized via the oxidation process of Cu foil in NH4OH solution at $50-70^{\circ}C$. The gas sensing properties of the as-prepared CuO nanoplates were examined with $C_2H_5OH$, $CH_3COCH_3$, and $NH_3$ at $200-360^{\circ}C$.