• Title/Summary/Keyword: 원판

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Effect of disc displacement on the bony change and disc configuration of TMJ (악관절 관절원판 위치변화가 관절원판 형태 및 골변화에 미치는 영향)

  • Kim Jin-Hoa;Lee Wan;Lee Byung-Do
    • Imaging Science in Dentistry
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    • v.36 no.1
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    • pp.17-24
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    • 2006

  • Purpose : The objective of this study was to investigate the effect of TMJ disc displacement on the TMJ disc configuration and surrounding osseous structure. Materials and Methods : The proton density and 72-weighted MR images of 57 TMJs were retrospectively studied. These TMJs were divided into three groups according to the anterior disc displacement status on MR sagittal images, those were the normal, anterior disc displacement with reduction (ADWR), anterior disc displacement without reduction (ADWOR). The frequency of disc configuration and surrounding bony change, the border status between articular disc and retrodiscal tissue were investigated according to the positional change of articular disc. Results : There were significant statistical differences of chi-square statistics of TMJ disc configurational type between normal and ADWR/ADWOR group, respectively. Surrounding bony change frequently appeared in ADWOR and a statistically significant difference of chi-square statistics of bony change frequency between normal and ADWOR group was observed. Conclusion : These results suggested that the disc configuration and bony change of TMJ are strongly related to TMJ disc displacement.

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Similarity analysis of a forced uniform flow impinging on a rotating disk in a vapor deposition process (증착공정에서의 회전원판 정체점유동에 대한 상사해석)

  • Song, Chang-Geol;Hwang, Jeong-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.3
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    • pp.371-379
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    • 1997

  • A theoretical study for a forced uniform flow impinging on a rotating disk, typically involved in Chemical Vapor Deposition(CVD) and Vapor-phase Axial Deposition(VAD) processes, has been carried out. A set of exact solutions for flow and temperature fields are developed by employing a similarity variable obtained from force balance on a control volume near the disk. The solutions depend on the rotating speed of the disk, .omega., and the forced flow speed toward the disk, a. For constant forced flow speed, the overall boundary layer thickness decreases when the rotating speed increases. Approximately 5%, 15%, and 30% decreases of the thickness are obtained for .omega./a = 2, 5, and 10, respectively, compared to the case of .omega./a = 0 (axisymmetric stagnation point flow). For constant rotating disk speed the boundary layer thickness immediately decreases as the forced flow speed increases, compared to the case of .omega./a .rarw. .inf. (induced flow near a rotating disk). Effects of .omega. and a on heat transfer coefficient are studied and explained with the boundary layer characteristics.

  • https://doi.org/10.22634/KSME-B.1997.21.3.371 인용 PDF