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        검색결과 141

        61.
        2010.06 구독 인증기관 무료, 개인회원 유료
        4,000원
        62.
        2010.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cubic boron nitride (c-BN) is a promising material for use in many potential applications because of its outstanding physical properties such as high thermal stability, high abrasive wear resistance, and super hardness. Even though 316L austenitic stainless steel (STS) has poor wear resistance causing it to be toxic in the body due to wear and material chips, 316L STS has been used for implant biomaterials in orthopedics due to its good corrosion resistance and mechanical properties. Therefore, in the present study, c-BN films with a B4C layer were applied to a 316L STS specimen in order to improve its wear resistance. The deposition of the c-BN films was performed using an r.f. (13.56 MHz) magnetron sputtering system with a B4C target. The coating layers were characterized using XPS and SEM, and the mechanical properties were investigated using a nanoindenter. The friction coefficient of the c-BN coated 316L STS steel was obtained using a pin-on-disk according to the ASTM G163-99. The thickness of the obtained c-BN and B4C were about 220 nm and 630 nm, respectively. The high resolution XPS spectra analysis of B1s and N1s revealed that the c-BN film was mainly composed of sp3 BN bonds. The hardness and elastic modulus of the c-BN measured by the nanoindenter were 46.8 GPa and 345.7 GPa, respectively. The friction coefficient of the c-BN coated 316L STS was decreased from 3.5 to 1.6. The wear property of the c-BN coated 316L STS was enhanced by a factor of two.
        4,000원
        63.
        2009.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Embedding of active devices in a printed circuit board has increasingly been adopted as a future electronic technology due to its promotion of high density, high speed and high performance. One responsible technology is to embedded active device into a dielectric substrate with a build-up process, for example a chipin-substrate (CiS) structure. In this study, desmear treatment was performed before Cu metallization on an FR-4 surface in order to improve interfacial adhesion between electroless-plated Cu and FR-4 substrate in Cu via structures in CiS systems. Surface analyses using atomic force microscopy and x-ray photoemission spectroscopy were systematically performed to understand the fundamental adhesion mechanism; results were correlated with peel strength measured by a 90o peel test. Interfacial bonding mechanism between electrolessplated Cu and FR-4 substrate seems to be dominated by a chemical bonding effect resulting from the selective activation of chemical bonding between carbon and oxygen through a rearrangement of C-C bonding rather than from a mechanical interlocking effect. In fact, desmear wet treatment could result in extensive degradation of FR-4 cohesive strength when compared to dry surface-treated Cu/FR-4 structures.
        4,000원
        64.
        2009.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Recently, metal molding has become essential not only for automobile parts, but also mass production, and has greatly influenced production costs as well as the quality of products. Its surface has been treated by carburizing, nitriding and induction hardening, but these existing treatments cause considerable deformation and increase the expense of postprocessing after treatment; furthermore, these treatments cannot be easily applied to parts that requiring the hardening of only a certain section. This is because the treatment cannot heat the material homogeneously, nor can it heat all of it. Laser surface treatment was developed to overcome these disadvantages, and, when the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source. To estimate this, microstructural changes and hardness characteristics of three parts (the surface treatment part, heat affect zone, and parental material) are observed with the change of laser beam speed and surface temperature. Moreover, the depth of the hardened area is observed with the change of the laser beam speed and temperature.
        4,000원
        65.
        2009.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper deals with the effects of the surfactant and preplate process (sensitization and activation) on electroless copper plating on carbon nano-fiber (CNF). Ultrasonic irradiation was applied both during dispersion of CNF and during electroless plating containing preplate process. The dispersion of CNF and flatness of the plated copper film were discussed based on the changes in surfactant concentration and preplate process time. It was clearly shown that high concentration of surfactant and long time of preplate process could promote the agglomeration of CNF and uneven copper plating on CNF.
        4,000원
        66.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to observe the histopathologic reaction in vital bone to various surface treated implants. For this purpose, ten New Zealand Albino rabbits, weighing 3.3 to 4kg were used as experimental animals. All the experimental groups divided into five groups; 1) Machined surface as control, 2) RBM(resorbable blast media), 3) RBM etched nitric acid solution, 4) RBM etched sodium hydroxide solution, 5) RBM etched acid, alkali, and heat treated group on each. All the surfaces of implants were examined under the scannning electron microscope to distinguish the differences between each experimental groups compare to that on the control group. All the rabbits were implanted into the tibial metaphyses of rabbits. On the 4th and 8th week after implantations, all the experimental rabbits were sacrificed. All the tissues containing each implanted materials were fixed in ethyl alcohol, and embedded in spurr resin as usual manner, sectioned in 10μm or more thickness, grinded, stained with the Villanuevaʼs osteochrome bone stain method and examined histopatholgically. For the fluorescence microscopic examination, three kind of fluorescence dyes, Oxytetracycline, Alizarin-Complexone, and Xylenol-Orange were injected to put into the bone to implant interface produced polychromatic fluorescence labelling on the 1st week, 2nd week, and 5th week on each. On the 8th week after experiments, the animals sacrificed, and the tissues containing the implants were taken, fixed in ethyl alcohol and embedded in spurr resin, sectioned, grounded 10um in thickness and examined under the fluorescence microscope. Following results were obtained; On the scanning electron microscopic examination of the implants, dull cracks, continuous linear indentations were revealed on the machined surface implant, irregular multiple leaflike eruptions on the RBM, and more sharp porous indentation with multiple complicated c rack s on the RBM acid etched surface, and more dull margins on complicated porous indentation on the RBM alkalic etched surface and more dull and less indented particles were noted on the RBM, acid, alkalic etched, heat treated surface, On the histopathologic examination, on the 4th week after experiment, complete osseointegation was noted between the implant and cortical bone on the collar and the apex lesion. and in parts, small newly formed bone spicules directly attached to the screws, and osteoid tissues were revealed in marrow tissues, in all experimental groups. On the histopathologic examination, on the 8th week after experiment, osseointegration is more increased compare to that on the 4th week group, the amount of bone trabeculae and osteoid tissues directly fused to screw of implants were markedly increased. On fluorescence examination, band or linear shape was witnessed on the boarder of compact bone and marrow tissues, and on bone trabeculae according to the formed age. and precipitated as granular and globular shape on the haversian canals. These results indicate that the surface treated method used for the present study render the implants compatible to bone tissue but the tissue compartibility is not different among the surface treated implants.
        4,600원
        67.
        2008.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Porous Ti implant samples were fabricated by the sintering of spherical Ti powders in a high vacuum furnace. To increase their surface area and biocompatibility, anodic oxidation and a hydrothermal treatment were then applied. Electrolytes in a mixture of glycerophosphate and calcium acetate were used for the anodizing treatment. The resulting oxide layer was found to have precipitated in the phase form of anatase TiO2 and nano-scaled hydroxyapatite on the porous Ti implant surface. The porous Ti implant can be modified via an anodic oxidation method and a hydrothermal treatment for the enhancement of the bioactivity, and current multi-surface treatments can be applied for use in a dental implant system.
        4,000원
        76.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 다양한 표면처리 공법에 따른 소음도를 비교 분석하여 소음 감소효과에 적합한 타이닝 방법을 제안하였다. 기존 문헌조사 결과 종방향 타이닝이 소음감소 효과에 우수한 결과를 보인다는 것을 바탕으로 국내 시험도로 일부구간에 표면처리 방법을 적용하였다. 승용차의 경우 일정간격 18mm 종방향 타이닝이 다른 비교구간보다 약 2~3dB(A) 소음 감소효과가 있다. 덤프트럭으로 외부소음을 측정하여 주파수 분석한 결과 200~600Hz 사이에서 peak frequency point가 발생하는 것을 알 수 있었다 또한, 승용차의 경우 1000Hz부근에서 소음 발생이 가장 큰 것으로 나타났다 차량 내부 소음 측정결과 표면처리 방법에 따라 소음 정도가 큰 폭으로 변화하지 않았으나, 차량 외부에서는 크게 변화하였다. 따라서 표면처리 방법은 소음도에 중요한 영향을 미치는 인자로 볼 수 있다. 표면처리에 따른 미끄럼 저항값 측정결과 종방향 타이닝이 횡방향 타이닝에 비해 낮게 나타났지만 전체적으로 양호한 결과를 보였다. 본 실험 결과는 시공 초기의 값이므로 공용 이후의 지속적인 조사가 필요하다.
        4,600원
        77.
        2004.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is boner process of stone manufacturing to become quality down of stone to consolidated micro crack appearance of stone surface and biotite by fire that is to be route process in stone surface by flame of LPG. And then, it is develop that stone surface process equipment by automation for the work method of boner process can be substitute work method by shotball blasting. To developement of equipment, There is to be down noise and dust. Acording to remove calamity growth hazardous substance in the work environment, there is to solve workplace avoidance factor. We have taken Taguchi's parameter design approch, specifically orthogonal array, and determined the optimal levels of stone surface through analysis of the experimental results using SIN ratio.
        4,300원
        79.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is boner process of stone manufacturing to become quality down of stone to consolidated micro crack appearance of stone surface and biotite by fire that is to be route process in stone surface by flame of LPG. And then, it is develop that stone surf
        4,000원
        80.
        2003.05 구독 인증기관 무료, 개인회원 유료
        There is boner process of stone manufacturing to become quality down of stone to consolidated micro crack appearance of stone surface and biotite by fire that is to be route process in stone surface by flame of LPG. And then, it is develop that stone surface process equipment by automation for the work method of boner process can be substitute work method by water jet to development of equipment. There is to be down noise and dust. According to remove calamity growth hazardous substance in the work environment, there is to solve workplace avoidance factor.
        4,000원
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