• Korean Journal of Metals and Materials
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• v.47 no.10
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• pp.675-680
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• 2009

Effects of $85^{\circ}C/85%$ Temperature/Humidity (T/H) treatment conditions on the peel strength of an electroless-plated Ni/polyimide system were investigated from a $180^{\circ}$ peel test. Peel strength between electroless-plated Ni and polyimide monotonically decreased from $37.4{\pm}5.6g/mm$ to $22.0{\pm}2.7g/mm$ for variation of T/H treatment time from 0 to 1000 hrs. The interfacial bonding mechanism between Ni and polyimide appears to be closely related to Ni-O bonding at the Ni/polyimide interface. The decrease in peel strength due to T/H treatment appears to be related to polyimide degradation due to moisture penetration through the interface and the bulk polyimide itself.

• Korean Journal of Metals and Materials
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• v.48 no.4
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• pp.369-375
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• 2010

Ti-6Al-4V ELI alloy, which is commonly used as a biomaterial, is associated with a high elastic modulus and poor biocompatibility. This alloy presents a variety of problems on several areas. Therefore, the development of good non-toxic biocompatible biomaterials with a low elastic modulus is necessary. Particularly, hydroxyapatite (HA) is an attractive material for human tissue implantation. This material is widely used as artificial bone due to its good biocompatibility and similar composition to human bone. Many scientists have studied the fabrication of HA as a biomaterial. However, applications of bulk HA compact are hindered by the low strength of HA when it is sintered. Therefore, HA has been coated on Ti or Ti alloy to facilitate good bonding between tissue and the HA surface. However, there are many problems when doing this, such as the low bonding strength between HA and Ti due to the different thermal expansion coefficients and mechanical properties. In this study, a Ti-HA composite with a porous surface was successfully fabricated by pulse current activated sintering (PCAS) and a subsequent leaching process.

• Advances in nano research
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• v.15 no.1
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• pp.49-57
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• 2023

As composite materials are used in many applications, the modern world looks forward to significant progress. An overview of the application of composite fiber materials in sports equipment is provided in this article, focusing primarily on the advantages of these materials when applied to sports equipment, as well as an Analysis of the influence of sports equipment of fiber-reinforced composite material on social sports development. The present study investigated surface morphology and physical and mechanical properties of S-glass fiber epoxy composites containing Al₂O₃ nanofillers (for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%). A mechanical stirrer and ultrasonication combined the Al₂O₃ nanofiller with the matrix in varying amounts. A compression molding method was used to produce sheet composites. A first physical observation is well done, which confirms that nanoparticles are deposited on the fiber, and adhesive bonds are formed. Al₂O₃ nanofiller crystalline structure was investigated by X-ray diffraction, and its surface morphology was examined by scanning electron microscope (SEM). In the experimental test, nanofiller content was added at a rate of 1, 2, and 3% by weight, which caused a gradual decrease in void fraction by 2.851, 2.533, and 1.724%, respectively, an increase from 2.7%. The atomic bonding mechanism shows molecular bonding between nanoparticles and fibers. At temperatures between 60 ℃ and 380 ℃, Thermogravimetric Analysis (TGA) analysis shows that NPs deposition improves the thermal properties of the fibers and causes negligible weight reduction (percentage). Thermal stability of the composites was therefore presented up to 380 ℃. The Fourier Transform Infrared Spectrometer (FTIR) spectrum confirms that nanoparticles have been deposited successfully on the fiber.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.793-796
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• 2005

In this paper, we propose a method which can improve uniformity of a miniaturized electron beam array for inspection of very small pattern with high speed using vertical interconnection. This method enables the individual control of columns so that it can reduce the deviation of beam current, beam size, scan range and so on. The test device that used vertical interconnection method was fabricated by multiple wafer bonding and metal reflow. Two silicon and one glass wafers were bonded and metal interconnection by melting of electroplated AuSn was performed. The contact resistance was under $10{\Omega}$.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.555-560
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• 2002

Brazing of Al to Cu using AI-Si-Mg-Bi brazing alloy has been carried out in the vacuum furnace. In the bonded interlayer, there were two kinds of intermetallic compounds. One of these intermetallic compounds was e phase and the other was b phase. The growth of b phase was controlled by diffusion Al into Cu. Deformation behavior of Al-Cu brazing joint was brittle without deformation of the base metal. Shear strength of the joint was only about 20MPa. The shear specimen broken in the intermetallic compound, which was mainly e phase. Shear strength did not depend on the bonding temperature.

• International Journal of Safety
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• v.9 no.1
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• pp.43-46
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• 2010

In the recycle process of organic solvent, the atmospheric oxygen can cause autoxidation and product peroxide. The time-saving method to evaluate the hazards has been required. In this study, oxygen pressure monitoring experiment was proposed as a new method to evaluate autoxidative resistances of solvents. Some of organic solvents were pressurized by oxygen and kept under isothermal condition. At the same time, the pressure in the vessel tracked. Iodometrical titration, thermal analysis and spectroscopic analysis were performed to measure peroxide concentration, the heat of reaction and chemical bonding change. From the results that THF has larger oxygen consumption rate than CPME, it is considered that autoxidative resistance of THF is lower than that of CPME. This method enables to obtain results in shorter time than other methods. These experimental results were consistent with the previous research with longer test durations [1-2].

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.179.2-179.2
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• 2014

Carbon nanotubes (CNT)-metal contacts play an important role in nanoelectronics applications such as field-effect transistor (FET) devices. Using Al and (10,0) CNT, we have recently showed that the CNT-metal contacts mediated via topological defects within CNT exhibits intrinsically low contact resistance, thanks to the preservation of the sp2 bonding network at the metal-CNT contacts.[1] It is well-established that metals with good wetting property such as Pd consistently yield good contacts to both metallic and semiconducting CNTs. In this work, the electronic and charge transport properties of the interfaces between capped CNT and Pd will be investigated based on first-principles computations and compared with previous results obtained for the Al electrodes.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.548-548
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• 2012

Thermomechanical and surface chemical properties of composite films of poly(D, L-lactic-co-glycolic acid) (PLGA) were significantly improved by the addition of graphene oxide (GO) nanosheets as nanoscale fillers to the PLGA polymer matrix. Enhanced thermomechanical properties of the PLGA/GO (2 wt.%) composite film, including an increase in the crystallization temperature and reduction in the weight loss, were observed. The tensile modulus of a composite film with increased GO fraction was presumably enhanced due to strong chemical bonding between the GO nanosheets and PLGA matrix. Enhanced hydrophilicity of the composite film due to embedded GO nanosheets also improved the biocompatibility of the composite film. Improved thermomechanical properties and biocompatibility of the PLGA composite films embedded with GO nanosheets may be applicable to biomedical applications such as scaffolds.

• Journal of the Semiconductor & Display Technology
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• v.4 no.3 s.12
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• pp.5-9
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• 2005

The bonding structure of organic materials such as fluorinated amorphous carbon films was classified into two types due to the chemical shifts. The electrical properties of fluorinated amorphous carbon films also showed very different effect of two types notwithstanding a very little difference. Fluorinated amorphous carbon films with the cross-link break-age structure existed large leakage current resulting from effect of the electron tunneling. Increasing the cation due to the electron-deficient group increased the barrier height of the films with the cross-link amorphous structure, therefore the electric characteristic of the final materials with low dielectric constant was also improved. The lowest dielectric constant is 2.3 at the sample with the cross-link amorphous structure.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.67-72
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• 2005

The bonding structure of organic materials such as fluorinated amorphous carbon films was classified into two types due to the chemical shifts. The electrical properties of fluorinated amorphous carbon films also showed very different effect of two types notwithstanding a very little difference. Fluorinated amorphous carbon films with the cross-link breakage structure existed large leakage current resulting from effect of the electron tunneling. Increasing the cation due to the electron-deficient group increased the barrier height of the films with the cross-link amorphous structure, therefore the electric characteristic of the final materials with low dielectric constant was also improved. The lowest dielectric constant is 2.3 at the sample with the cross-link amorphous structure.