• Title, Summary, Keyword: Pure Metal

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SPECTROPHOTOMETRIC ANALYSIS OF THE INFLUENCE OF METAL SUBSTRATE ON THE COLOR OF CERAMIC (금속하부구조물이 도재의 색조에 미치는 영향에 대한 분광측색분석)

  • Lee Su-Ok;Woo Yi-Hyung;Choi Dae-Gyun;Kwon Keung-Rok
    • The Journal of Korean Academy of Prosthodontics
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    • v.41 no.2
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    • pp.148-159
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    • 2003
  • Statement of problem Metal-ceramic restorations have been used extensively by dental clinicians for nearly 40 years. Strength an functional ability of metal-ceramic restorations are proved to be satisfying, However esthetics and biocompatibility of metal alloy which is used in metal-ceramic restoration is not ideal. Using pure gold as an alternative, have advantage of esthetics, biocompatibility over conventional metal alloy. But there had been little article which studied on the color effect of pure gold on fual porcelain color. Purpose The purpose of this study was to spectrophotometrically evaluate the difference between color of metal alloy(Au-Pt, Ni-Cr) and pure gold, during color masking procedure with opaque porcelain and to analyze the differences, Material and Methods Three types of metal - base metal(Ni-Cr), high gold alloy(Au-Pt), pure gold(GES) - specimen were fabricated 1cm in diameter. Four steps were established - after finishing, after pre-coditioning, after application of first opaque porcelain(0.08mm in thickness), after application of second opaque porcelain(0.15mm in thickness)- and tested color with spectrophotometer every each steps and analyzed with $CIEL^*a^*b^*$ color order system. One-Way ANOVA test was used to and out if there were significant differences between groups tested and Shaffe multiple comparison was used to identify where the differences were. Results 1. After finishing and pre-conditioning, pure gold(GES) group showed most high values in $L^*,a^*,b^*$. 2. After application of first opaque porcelain(0.08mm in thickness), after application of second opaque porcelain(0.15mm in thickness), pure gold(GES) group showed the least difference in $L^*,a^*,b^*$ values and the lowest ${\Delta}E$ value(${\Delta}E$=0.63). 3. After application of first opaque porcelain and after application of second opaque porcelain differences that were significant (P<0.05) between groups were found only in $a^*$ values. 4. Base metal alloy group showed the lowest $a^*$ value in test after application of first opaque porcelain and the highest value in test after application of first opaque porcelain Conclusion Pure gold group and high gold group showed higher $a^*$ values than base metal group when tested after 0.08mm thickness of opaque porcelain was applied and pure gold group showed much similar $L^*,a^*,b^*$ values between 0.08mm thickness and 0.15mm thickness of opaque porcelain. This meant that pure gold was more easily masked by opaque porcelain than the other two groups.

Analysis of Flux′s Conduct by Bead Welding in SAW (SAW 비드 용접을 통한 Flux 거동 해석)

  • 이재윤;이성호;이보영
    • Proceedings of the KWS Conference
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    • pp.245-247
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    • 2003
  • Elements of Pure Weld Metal(PWM) is important factor that understand to analyze Flux's conduct in SAW welding. For elements of PWM were got, Pile-up welding over 10 floor have used in the past. But, it take a long time to analyze elements of PWM in this method. Elements of Pure Weld Metal is needed to seize more easily. In this research, Bead welding is used to graps an element of Pure Weld Metal using mathematical formula which get to be derivation.

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Single Walled Carbon Nanotubes-Reinforced Metal Matrix Composite Materials Fabricated by Spark Plasma Sintering (방전플라즈마 소결공정으로 제조된 단일벽탄소나노튜브 강화 금속기지 복합재료)

  • Kwon, Hansang
    • Journal of Power System Engineering
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    • v.21 no.4
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    • pp.94-99
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    • 2017
  • Single walled carbon nanotubes were mixed with various metal powders by mechanical ball milling and sintered by spark plasma sintering processes. Two compositional (0.1 and 1 vol%) of the single walled carbon nanotubes were dispersed onto the pure aluminum, 5052 aluminum alloy, pure titanium, Ti6Al4Vanadium alloy, pure copper, and stainless steel 316L. Each composite powders were spark plasma sintered at $600^{\circ}C$ and well synthesized regardless of the matrices. Vickers hardness of the composite materials was measured and they exhibited higher values regardless of the carbon nanotubes composition than those of the pure materials. Moreover, single walled carbon nanotubes reinforced copper matrix composites showed highest enhancement between the other metal matrices system. We believe that low energy mechanical ball milling and spark plasma sintering processes are useful tool for fabricating of the carbon nanotubes-reinforced various metal matrices composite materials. The single walled carbon nanotubes-reinforced various metal matrices composite materials could be used as an engineering parts in many kind of industrial fields such as aviation, transportation and electro technologies etc. However, detail strengthening mechanism should be carefully investigated.

Novel solvothermal approach to hydrophilic nanoparticles of late transition elements and its evaluation by nanoparticle tracking analysis

  • Dutilleul, Marion Collart;Seisenbaeva, Gulaim A.;Kessler, Vadim G.
    • Advances in nano research
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    • v.2 no.2
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    • pp.77-88
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    • 2014
  • Solvothermal treatment of late transition metal acetylacetonates in a novel medium composed either of pure acetophenone or acetophenone mixtures with amino alcohols offers a general approach to uniform hydrophilic metal nanoparticles with high crystallinity and low degree of aggregation. Both pure metal and mixed-metal particles can be accesses by this approach. The produced materials have been characterized by SEM-EDS, TEM, FTIR in the solid state and by Nanoparticle Tracking Analysis in solutions. The chemical mechanisms of the reactions producing nanoparticles has been followed by NMR. Carrying out the process in pure acetophenone produces palladium metal, copper metal with minor impurity of $Cu_2O$, and NiO. The synthesis starting from the mixtures of Pd and Ni acetylacetonates with up to 20 mol% of Pd, renders in minor yield the palladium-based metal alloy along with nickel oxide as the major phase. Even the synthesis starting from a mixed solution of $Cu(acac)_2$ and $Ni(acac)_2$ produces oxides as major products. The situation is improved when aminoalcohols such as 2-aminoethanol or 2-dimethylamino propanol are added to the synthesis medium. The particles in this case contain metallic elements and pairs of individual metals (not metal alloys) when produced from mixed precursor solutions in this case.

Synthesis and comparison of pure TiO2 and metal/non-metal doped TiO2 as a photocatalyst

  • Moon, Jiyeon;Lee, Kyusang;Kim, Seonmin
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.370.1-370.1
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    • 2016
  • Volatile organic compounds (VOCs) are considered hazardous air pollutants and these are emitted from building materials and household products. VOCs can cause global warming as well as human sickness, and even cancer. Photocatalysis provides a way of converting VOCs into harmless materials. Various researches have shown that $TiO_2$ is the most efficient photocatalysts due to its excellent activity. In this study, metal/non-metal doped $TiO_2$ particles are synthesized for the enhancement of the photocatalytic properties of pure $TiO_2$. By metal/non-metal doping, band gap energies of prepared samples were analyzed by UV/Visible spectrophotometer. The physical and chemical properties of synthesized powder were characterized by field emission scanning electron microscope, by BET for measuring their specific surface area, and by XRD for phase identification and particle size determination. Degradation ability for p-xylene was evaluated through monitoring the concentration in a closed chamber. Relation between their properties and decomposition abilities for VOC were evaluated based on the experimental results.

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The Effect of Cooling method on the Surface Reaction Zone of CP Titanium Casting Body (티타늄 주조체 냉각방법이 표면반응층에 미치는 영향)

  • Moom, Soo;Choi, Seog-Soon;Moon, Il
    • Journal of Technologic Dentistry
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    • v.23 no.2
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    • pp.203-210
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    • 2002
  • This test is to conduct applied research the reaction area of the Ti-cast metal body which is made use of Dental Phosphate-silica alumina bonded investment material selling at a market, and the cooling method is how to effect on the acicular. The experimentation is as followings, 1. Experimental specimens After invest with Dental Phosphate-silica alumina bonded investment material, the $10{\times}10{\times}1.0mm^3$ wax pattern was casted by Dental high vacuum argon centrifugal casting machine. 2. Test We can analyze SEM/EDS, XRD utilize the fractography(an optical microscope). 3. Conclusion The pure cast metal body constituted of reaction products layer, stability layer and contamination layer. This pure cast have no connection with the cooling condition. The pure Titanium shows difference in a component distribution according to the cooling condition. Through this experimentation we can establish that acicular in the pure Ti-cast metal is consist of Hexagonal structure a=2.9505$\AA$, c=4.6826$\AA$.

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Analysis of the Formation of Rear Contact for Monocrystalline Silicon Solar Cells (단결정 실리콘 태양전지의 후면 전극형성에 관한 비교분석)

  • Kwon, Hyuk-Yong;Lee, Jae-Doo;Kim, Min-Jeong;Lee, Soo-Hong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.7
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    • pp.571-574
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    • 2010
  • Surface recombination loss should be reduced for high efficiency of solar cells. To reduce this loss, the BSF (back surface field) is used. The BSF on the back of the p-type wafer forms a p+layer, which prevents the activity of electrons of the p-area for the rear recombination. As a result, the leakage current is reduced and the rear-contact has a good Ohmic contact. Therefore, the open-circuit-voltage (Voc) and fill factor (FF) of solar cells are increased. This paper investigates the formation of the rear contact process by comparing aluminum-paste (Al-paste) with pure aluminum-metal(99.9%). Under the vacuum evaporation process, pure aluminum-metal(99.9%) provides high conductivity and low contact resistance of $4.2\;m{\Omega}cm$, but It is difficult to apply the standard industrial process to it because high vacuum is needed, and it's more expensive than the commercial equipment. On the other hand, using the Al-paste process by screen printing is simple for the formation of metal contact, and it is possible to produce the standard industrial process. However, Al-paste used in screen printing is lower than the conductivity of pure aluminum-metal(99.9) because of its mass glass frit. In this study, contact resistances were measured by a 4-point probe. The contact resistance of pure aluminum-metal was $4.2\;m{\Omega}cm$ and that of Al-paste was $35.69\;m{\Omega}cm$. Then the rear contact was analyzed by scanning electron microscope (SEM).

Sliding Wear Behavior of Pure Metal, Fe and Cu Having a Cubic Crystal System (입방정계 순 금속 Fe, Cu의 미끄럼 마멸 거동)

  • Yi, S.K.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.19 no.6
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    • pp.357-362
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    • 2010
  • Dry sliding wear behavior of pure Fe and Cu which have BCC and FCC crystal structure, respectively, was investigated. The wear characteristics of the pure metals with different crystal structure were compared. Dry sliding wear tests were carried out using a pin-on-disk wear tester at various loads under the constant sliding speed condition of 0.15 m/s against a silica ball at room temperature. Sliding distance was fixed as 600 m for all wear tests. Wear rate of a specimen was calculated by dividing the weight loss of the specimen after the test by the specific gravity and sliding distance. Worn surfaces and wear debris were analyzed by SEM. The wear of both pure Fe and Cu proceeded with surface deformation, resulting in similar wear rates despite of their structure difference under the current test conditions. Wear rates of both metals were low if the surface deformation due to wear forms thick surface-deformation layer that is strain hardened beneath the wearing surface. The pure Cu specimens showed a lot of oxides on the worn surface when tested at low loads less than 5 N, which resulted in very low wear rate.

Friction Welding of Spheroidal Graphite Cast Iron and 2024 Aluminium Alloys using Insert Metal (삽입금속을 사용한 구상흑연주철과 2024 알루미늄합금의 마찰압접에 관한 연구)

  • KIM CHANG-GYU;KIM CHI-OK;KIM KWANG-ILL
    • Journal of Ocean Engineering and Technology
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    • v.17 no.5
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    • pp.76-81
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    • 2003
  • Friction welding of GCD45 spheroidal graphite cast iron and 2024 aluminum alloy has been studied, especially in terms of the joint faces and strength of friction welding. For appropriate results of the friction welding of GCD45 graphite cast iron and 2024 aluminum alloy, an insert of A1050 pure aluminum metal was used. The joint strength of the A1050 pure aluminum insert approached the maximum strength of 165.7Mpa, compared to 128MPa for the joint between GCD45 graphite cast iron and A1050 pure aluminum without the insert metal. Maximum strength, 165.7Mpa, was possible for the following optimum conditions: 20MPa for the friction pressure, P1, 60MPa for the upsetting pressure, P2, 1 second for the friction time, t1, 3000rpm for the rotation, N, and 0.3 seconds for the brake time, tB.

A Study on the Fabrication Process and Melt Infiltration of Salt Core in Squeeze Casting Method (스퀴즈캐스팅용 Salt Core의 제조 및 용탕침투성에 관한 연구)

  • Kim, Ki-Bae;Noh, Sang-Woo;Lee, Ho-In;Nam, Tae-Woon
    • Journal of Korea Foundry Society
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    • v.17 no.4
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    • pp.402-410
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    • 1997
  • Developing a salt core for squeeze casting process, two different salt cores(pure salt core and mixed salt core) were fabricated and investigated. Pure salt core was composed of 100% NaCl and mixed salt core was made by mixtures of NaCl with MgO(1%), $Na_2B_4O_7$(2%), and talc(1%) as a binder or a strengthening agent. Salt cores were compacted to various theoretical density, heat treated, and then squeeze-cast with molten Al alloy(AC8A). The compression strength of salt cores were measured and the squeeze-cast products were examined for shape retention, infiltration of molten metal into the cores, and microstructures. The shape of salt core compacted at above 75% of the theoretical density was maintained stably. The higher theoretical density of salt cores gave higher compression strength, and the compression strength of mixed salt core was higher than that of pure salt core. Namely at 90% theoretical density, the compression strength of mixed salt core was $6.3 kg/mm^2$, compared to $4.6 kgmm^2$ for pure salt core. At a squeeze casting pressure of $1000 kg/cm^2$, molten Al alloy was infiltrated into pure salt core of under 85% of the theoretical density. At squeeze casting pressure of $1000 kg/cm^2$, only mixed salt core above 90% of the theoretical density were valid, but the shape of the core was altered in the case of pure salt core at 90% of theoretical density. A key factor for developing a salt core for squeeze casting process was estimated as the ultimate compressive strength of salt core.

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