• Title/Summary/Keyword: Metal-framework

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Cr-Co removable partial denture treatment fabricated by selective laser melting: a case report (Selective Laser Melting을 이용한 코발트-크롬 가철성 국소의치의 수복 증례)

  • Yim, Ji-Hun;Shin, Soo-Yeon
    • Journal of Dental Rehabilitation and Applied Science
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    • v.37 no.1
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    • pp.39-47
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    • 2021
  • Compared to conventional method, if metal framework of removable partial denture is fabricated by selective laser melting, various laboratory works are omitted, saving time and simplifying the process. In addition, metal framework with homogeneous density can be obtained, expecting excellent mechanical properties, especially resistance to fatigue fracture. In these cases, impression were taken using conventional methods in partial edentulous patients, master casts were fabricated and scanned to obtain digital data. After designing the metal frameworks on the scanned data, removable partial dentures were fabricated using selective laser melting methods. Through these procedure, satisfactory outcomes were achieved both in functional and esthetic aspects.

Quantitative Analysis of SO2 and NO2 Adsorption and Desorption on Quartz Crystal Microbalance Coated with Cobalt Gallate Metal-Organic Framework

  • Junhyuck Ahn;Taewook Kim;Sunghwan Park;Young-Sei Lee;Changyong Yim
    • Journal of Sensor Science and Technology
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    • v.32 no.3
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    • pp.147-153
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    • 2023
  • Metal-organic frameworks (MOFs) of cobalt gallate were synthesized and deposited on gold electrodes using self-assembly monolayers (SAMs) and hydrothermal processing. These MOF films exhibit strong adsorption capabilities for gaseous particulates, and the use of SAMs allows the synthesis and deposition processes to be completed in a single step. When cobalt gallate is mixed with SAMs, a coordination bond is formed between the cobalt ion and the carboxylate or hydroxyl groups of the SAMs, particularly under hydrothermal conditions. Additionally, the quartz crystal microbalance (QCM) gas sensor accurately measures the number of particulates adsorbed on the MOF films in real-time. Thus, the QCM gas sensor is a valuable tool for quantitatively measuring gases, such as SO2, NO2, and CO2. Furthermore, the QCM MOF film gas sensor was more effective for gas adsorption than the MOF particles alone and allowed the accurate modeling of gas adsorption. Moreover, the QCM MOF films accurately detect the adsorption-desorption mechanisms of SO2 and NO2, which exist as gaseous particulate matter, at specific gas concentrations.

Effect of Cobalt Loading on the Performance and Stability of Oxygen Reduction and Evolution Reactions in Rechargeable Zinc-air Batteries

  • Sheraz Ahmed;Joongpyo Shim;Gyungse Park
    • Journal of the Korean Chemical Society
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    • v.68 no.2
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    • pp.87-92
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    • 2024
  • The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.

A framework for geometrically non-linear gradient extended crystal plasticity coupled to heat conduction and damage

  • Ekh, Magnus;Bargmann, Swantje
    • Multiscale and Multiphysics Mechanics
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    • v.1 no.2
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    • pp.171-188
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    • 2016
  • Gradient enhanced theories of crystal plasticity enjoy great research interest. The focus of this work is on thermodynamically consistent modeling of grain size dependent hardening effects. In this contribution, we develop a model framework for damage coupled to gradient enhanced crystal thermoplasticity. The damage initiation is directly linked to the accumulated plastic slip. The theoretical setting is that of finite strains. Numerical results on single-crystalline metal showing the development of damage conclude the paper.

Adsorption and Photocatalytic Degradation of Dyes Using Synthesized Metal-Organic Framework NH2-MIL-101(Fe) (합성 금속-유기 골격체 NH2-MIL-101(Fe)를 이용한 염료의 흡착 및 광분해 제거)

  • Lee, Joon Yeob;Choi, Jeong-Hak
    • Journal of Environmental Science International
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    • v.27 no.7
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    • pp.611-620
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    • 2018
  • In this study, a metal-organic framework (MOF) material $NH_2$-MIL-101(Fe) was synthesized using the solvothermal method, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-visible spectrophotometry, field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and surface area measurements. The XRD pattern of the synthesized $NH_2$-MIL-101(Fe) was similar to the previously reported patterns of MIL-101 type materials, which indicated the successful synthesis of $NH_2$-MIL-101(Fe). The FT-IR spectrum showed the molecular structure and functional groups of the synthesized $NH_2$-MIL-101(Fe). The UV-visible absorbance spectrum indicated that the synthesized material could be activated as a photocatalyst under visible light irradiation. FE-SEM and TEM images showed the formation of hexagonal microspindle structures in the synthesized $NH_2$-MIL-101(Fe). Furthermore, the EDS spectrum indicated that the synthesized material consisted of Fe, N, O, and C elements. The synthesized $NH_2$-MIL-101(Fe) was then employed as an adsorbent and photocatalyst for the removal of Indigo carmine and Rhodamine B from aqueous solutions. The initial 30 min of adsorption for Indigo carmine and Rhodamine B without light irradiation achieved removal efficiencies of 83.6% and 70.7%, respectively. The removal efficiencies thereafter gradually increased with visible light irradiation for 180 min, and the overall removal efficiencies for Indigo carmine and Rhodamine B were 94.2% and 83.5%, respectively. These results indicate that the synthesized MOF material can be effectively applied as an adsorbent and photocatalyst for the removal of dyes.

3D printed surveyed restoration and metal framework in removable dentures: A case report (3D 프린팅 된 서베이드 금관과 금속 프레임워크를 이용한 양악 가철성 의치 수복 증례)

  • Song Yi Park;Sang-Won Park;Chan Park;Woohyung Jang;Kwi-Dug Yun
    • The Journal of Korean Academy of Prosthodontics
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    • v.61 no.2
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    • pp.153-159
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    • 2023
  • Computer-aided design-computer-aided manufacturing technology has been widely used in the manufacture of fixed prostheses including implants, but in the case of removable dentures, the analog method is still being used due to the errors such as a lack of fusion and over-fusion in selective laser meting process. With the recent development of CAD software, virtual surveying and framework design are made possible, and the designed file can be manufactured by milling or 3D printing. It replace the analog method of waxing and denture curing process and also can reduce the production time and cost. Therefore, this case is reported because good clinical results were obtained by digitally surveying on CAD software to produce a surveyed metal restoration and framework on maxillary and mandibular removable dentures.

Scalable Fabrications of Mixed-Matrix Membranes via Polymer Modification-Enabled In Situ Metal-Organic Framework Formation for Gas Separation: A Review (고분자 변형으로 가능해진 MOF의 원위치 형성을 이용한 혼합기질 기체분리막의 대면적화 가능한 제막)

  • Sunghwan Park;Young-Sei Lee
    • Applied Chemistry for Engineering
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    • v.34 no.3
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    • pp.213-220
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    • 2023
  • Mixed-matrix membranes (MMMs), which are composed of a polymer matrix filled with high-performance fillers as a dispersed phase, have been intensively studied for gas separations for the past 30 years. It has been demonstrated that MMMs exhibit superior gas separation performance compared to polymer membranes and are more scalable than polycrystalline membranes. Despite their potential, the commercialization of MMMs has yet to be reported due to several challenging issues. One of the major challenges of MMMs is the non-ideal interface between the continuous polymer phase and dispersed phase, which can result in defect formation (i.e., interfacial voids, etc.). With respect, many MMM studies have focused on addressing the issues through scientific approaches. The engineering approaches for facile and effective large-scale fabrication of MMMs, however, have been relatively underestimated. In this review paper, a novel strategy for fabricating MMMs in a facile and scalable manner using in situ metal-organic framework (MOF) formation is introduced. This new MMM fabrication methodology can effectively address the issues facing current MMMs, likely facilitating the commercialization of MMMs.

A Study on the Characteristics and Applying Methods of Metal in Contemporary Interior Design (현대 실내디자인에 있어서 금속소재 특성 및 적용방법에 관한 연구)

  • Lee, Jang-Son;Shim, Eun-Ju
    • Korean Institute of Interior Design Journal
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    • v.19 no.1
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    • pp.121-127
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    • 2010
  • Technological development are now encouraging new concepts in various fields of design, including material applications. Metal can be considered as the major material that represents modern design and technology since the industrial revolution. The objective of this study was to understand characteristics of metal as design material and various application methods in interior design. This study first examined basic qualities of metal and its history used in architectural design. Secondly, based on three qualities of metal such as physical, chemical, and mechanical the authors have analyzed projects built within recent 10 years regarding aspects of metal qualities, treatments. As results projects that uses a combination of two or more qualities and treatment seem to have a more interesting affects in interior space. Moreover, each affects are related to these four design keyword: visual distortion, de-materialization, hi-technology, and time-concept. The framework developed is hopes to be used as a basic design guideline, where metal is considered not just as a mere interior finish material but as a major creative source and inspiration in interior design.