• Title/Summary/Keyword: Refractory materials

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Multimodal Diagnostic Approach for Synovitis of the Wrist (수근관절 활액막염 원인 질환 진단을 위한 다중적 접근법)

  • Bae, Kee Jeong;Kim, Jihyeung;Yoon, Chan;Hong, Seong Hwa;Gong, Hyun Sik;Baek, Goo Hyun
    • Journal of the Korean Orthopaedic Association
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    • v.53 no.6
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    • pp.540-546
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    • 2018
  • Purpose: The purpose of this study was to suggest a multimodal diagnostic approach to determine the cause of the disease in patients diagnosed with synovitis of the wrist and who underwent synovectomy. Materials and Methods: Twenty-nine patients, who underwent contrast magnetic resonance imaging (MRI) preoperatively and synovectomy from January 2000 to December 2013, were reviewed retrospectively. Among them, 17 patients underwent a $Tc^{99m}$ white blood cell (WBC) scan preoperatively. In patients who met the diagnostic criteria of rheumatoid arthritis (RA), the diagnosis was confirmed as RA if the MRI finding or histology was compatible with RA. If the MRI finding and histology were disparate, the final diagnosis was made based on the histologic finding. Results: Of the nine patients who met the diagnostic criteria of RA, seven patients were finally diagnosed as RA and two patients as tuberculous arthritis. Of the 20 patients who did not meet the diagnostic criteria of RA, the MRI findings and histology were consistent with the same disease in 12 patients. In the remaining eight patients, five were diagnosed with nonspecific chronic synovitis, one with RA, and two with tuberculous arthritis based on the clinical findings, MRI, and histology findings. Conclusion: MRI and a WBC scan are very useful imaging modalities for diagnosing the causative condition of the wrist synovitis. A histology evaluation after synovectomy can also be useful in cases with a difficult diagnosis or are refractory to medications.

Distribution of Agalmatolite Mines in South Korea and Their Utilization (한국의 납석 광산 분포 현황 및 활용 방안)

  • Seong-Seung Kang;Taeyoo Na;Jeongdu Noh
    • The Journal of Engineering Geology
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    • v.33 no.4
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    • pp.543-553
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    • 2023
  • The current status of domestic a agalmatolite mines in South Korea was investigated with a view to establishing a stable supply of agalmatolite and managing its demand. Most mined agalmatolite deposits were formed through hydrothermal alteration of Mesozoic volcanic rocks. The physical characteristics of pyrophyllite, the main constituent mineral of agalmatolite, are as follows: specific gravity 2.65~2.90, hardness 1~2, density 1.60~1.80 g/cm3, refractoriness ≥29, and color white, gray, grayish white, grayish green, yellow, or yellowish green. Among the chemical components of domestic agalmatolite, SiO2 and Al2O3 contents are respectively 58.2~67.2 and 23.1~28.8 wt.% for pyrophyllite, 49.2~72.6 and 16.5~31.0 wt.% for pyrophyllite + dickite, 45.1 and 23.3 wt.% for pyrophyllite + illite, 43.1~82.3 and 11.4~35.8 wt.% for illite, and 37.6~69.0 and 19.6~35.3 wt.% for dickite. Domestic agalmatolite mines are concentrated mainly in the southwest and southeast of the Korean Peninsula, with some occurring in the northeast. Twenty-one mines currently produce agalmatolite in South Korea, with reserves in the order of Jeonnam (45.6%) > Chungbuk (30.8%) > Gyeongnam (13.0%) > Gangwon (4.8%), and Gyeongbuk (4.8%). The top 10 agalmatolite-producing mines are in the order of the Central Resources Mine (37.9%) > Wando Mine (25.6%) > Naju Ceramic Mine (13.4%) > Cheongseok-Sajiwon Mine (5.4%) > Gyeongju Mine (5.0%) > Baekam Mine (5.0%) > Minkyung-Nohwado Mine (3.3%) > Bugok Mine (2.3%) > Jinhae Pylphin Mine (2.2%) > Bohae Mine. Agalmatolite has low thermal conductivity, thermal expansion, thermal deformation, and expansion coefficients, low bulk density, high heat and corrosion resistance, and high sterilization and insecticidal efficiency. Accordingly, it is used in fields such as refractory, ceramic, cement additive, sterilization, and insecticide manufacturing and in filling materials. Its scope of use is expanding to high-tech industries, such as water treatment ceramic membranes, diesel exhaust gas-reduction ceramic filters, glass fibers, and LCD panels.