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The Characteristics of the Ozonizer with Cascade-Type Plate Electrode (Cascade형 평판전극 오존발생기의 특성)

  • Yoon, Dae-Hee;Song, Hyun-Jig;Lee, Sang-Keun;Park, Kwang-Seo;Kim, Jong-Hyun;Park, Won-Zoo;Lee, Kwong-Sik
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.5
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    • pp.80-87
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    • 2009
  • Recently, ozone has been utilized in various fields thanks to its effectiveness, and has been in ever-growing demand. Accordingly, various kinds of ozonizers have been examined among researchers. This paper is concerned with developing the cascade-type plate electrode ozonizer(PTO) for improvements of indoor air, water supply and drainage and investigating its characteristics. Four types of ozonizers have been devised according to their size, numbers and arrangement Electric discharge area of each type of ozonizer has the same size of 22,400[$mm^2$], and its discharge power has the maximum 40[w]. As the result of having studied ozone generation ozone concentration and ozone yield characteristics of each ozonizer, we found that the type of ozonizer in which eight plates were arranged into cascade type(PTO-4) was the most excellent one.

The Reliability and Relationships Between Thoracic Kyphosis, Postural Stiffness and Thoracic Rotation in Young Subjects (젊은 성인의 흉추후만지수 및 자세 경직도와 흉추회전각 간의 상관성과 신뢰도)

  • Jang, Hyun-Jeong;Kim, Suhn-Yeop;Kim, Myung-Jun
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.18 no.2
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    • pp.49-55
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    • 2012
  • Background: The purposes of this study were to: 1) investigate the relation between thoracic kyphosis, postural stiffness and thoracic rotation and 2) the intra-rater reliability of the measurement methods for thoracic kyphosis and rotation angle. Methods: Thirty-nine young adults (13 males, 26 females) participated in the study. Thoracic kyphosis was measured using a Flexicurve while standing in their usual relaxed posture and then in their maximally erector posture. Index of kyphosis (IK) measures taken in the relaxed and maximally erect positions were used to estimate postural stiffness. Thoracic rotation range of motion (ROM) was measured using universal goniometer and inclinometer in two positions. The association between the magnitude of the IK and thoracic stiffness and thoracic rotation ROM was also examined. Reliability was determined using intra-class correlation coefficients (ICC). Results: When measured from the mean relaxed IK (${\pm}SD$) was 7.42 (${\pm}1.47$) and mean erect IK was 4.92 (${\pm}1.63$) and mean IK ratio was 1.66 (${\pm}.65$). The relaxed IK was significantly correlated with the range of motion thoracic rotation in two positions (r=.503~580, p<.01). Conclusion: Thoracic kyphosis in relaxed position was associated with the range of motion thoracic rotation. Thoracic kyphosis measurement with the Flexicurve and range of motion 2 techniques of thoracic rotation showed good reliablity and may be a useful measurement tool in clinical practice.

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Simplified Nonlinear Dynamic Progressive Collapse Analysis of Welded Steel Moment Frames Using Collapse Spectrum (붕괴스펙트럼을 활용한 용접철골모멘트골조의 비선형 동적 연쇄붕괴 근사해석)

  • Lee, Cheol Ho;Kim, Seon Woong;Lee, Kyung Koo;Han, Kyu Hong
    • Journal of Korean Society of Steel Construction
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    • v.21 no.3
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    • pp.267-275
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    • 2009
  • This paper presents the behavior of column-removed double-span beams in welded steel moment frames and proposes a simplified nonlinear dynamic analysis method for the preliminary evaluation of progressive collapse potential. The nonlinear finite element analysis and the associated analytical study showed that the column gravity load and the beam span-to-depth ratio govern the maximum dynamic deformation demand of the double-span beams. Based on these results, the concept of a collapse spectrum, which describes the relationship between the gravity load parameter and the maximum chord rotation of the double-span beams, was newly proposed. A procedure for the application of the collapse spectrum to multi-story welded steel moment frames was then suggested. The inelastic dynamic finite element analysis results showed that the proposed method gives satisfactory prediction of the nonlinear progressive collapse behavior of welded steel moment frames.

Study on Material Characterization of Earthen Wall of Buddhist Mural Paintings in Joseon Dynasty (조선시대 사찰벽화 토벽체의 재질특성 연구)

  • Lee, Hwa Soo
    • Journal of Conservation Science
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    • v.32 no.1
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    • pp.75-88
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    • 2016
  • In this study, 5 mural paintings in the Buddhist temples of Joseon era were researched for component analysis on the soil contained in the walls. The results of particle size analysis showed that the ratio of particle contents were different in each layer. In the finishing layer, the distribution of the middle sand fraction is higher than that of the middle layer. The results of XRD analysis showed that quartz, feldspar, and clay mineral are the main components of sand, suggesting similar mineral composition to that of ordinary soil component. It seems weathered rocks were used for construction of the walls. The main chemical components detected from EDX analysis were Si, Al, Fe, and K. Also the SEM images showed sand or clay sized minerals. In conclusion, the walls of the buddhist mural paintings in Joseon Dynasty had been constructed by using the loess, and had been produced by using mixture of clay and sand particles of different sizes for each layer. This study identified the characteristics of the materials and the manufacturing technologies used on the walls of mural paintings of Buddhist temples in Joseon era.

Vibration Analysis of Mindlin Plates Using Polynomials Having the Property of Timoshenko Beam Functions (Timoshenko보함수 성질을 갖는 다항식을 이용한 Mindlin판유추 구조계의 진동해석)

  • J.H. Chung;T.Y. Chung;K.C. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.1
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    • pp.158-172
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    • 1992
  • In ships and offshore structures, there are many local structures formed of thick plates and/or having the form of double wall panels. For the vibration analysis of such a kind of structures, Mindlin plate theory which includes the effects of shear deformation and rotary inertia is usually adopted. In this paper, the vibration and dynamic sensitivity analysis of Mindlin plates having the boundary conditions elastically restrained against rotation have been accomplished using the Rayleigh-Ritz method. Polynomials having the property of the Timoshenko beam functions are introduced and used as trial functions in the spatial representation of the deflection and rotations of cross sections in two directions of the plates. The results obtained by the introduced polynomials gave nearly the same numerical results as those by the Timoshenko beam functions with the remarkable reduction of computational efforts especially in the dynamic sensitivity analysis.

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A study on the Interpretation Technique of Fall-Of-Potential Curve for Grounding Performance Evaluation of a Large Grounding Electrode Network (대규모 접지전극 망의 접지성능 평가를 위한 겉보기저항곡선의 해석에 관한 연구)

  • Choi, Jong-Kee;Ryu, Hee-Young;Lee, Dongil;Jung, Gil-Jo;Kim, Kyung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.2
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    • pp.49-54
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    • 2005
  • Measuring ground resistance is a typical way of performance evaluation of a grounding electrode. Among various ground resistance measurement methods, FOP (Fall-Of-Potential) method has been widely used, especially in case of a relatively large grounding electrode such as a substation grounding mesh grid Since FOP measurement line has to be increased as the size of grounding electrode increases, however, it is often that securing long enough FOP-line is practically impossible. In this paper, a sophisticated interpretation method of FOP measurement ma which is applicable to large grounding electrode networks, is presented.

Dependence of Magnetic and Magneto-Optic Properties on Deposition Angle in E-Beam EVaporated Co/Pt Multilayer Films (전자빔 증착 Co/Pt 다층박막에서 입사 선속의 방향에 따른 자기 및 자기광학적 성질 변화 연구)

  • 문기석;신성철
    • Journal of the Korean Magnetics Society
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    • v.4 no.4
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    • pp.313-318
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    • 1994
  • We have investigated the effects of deposition angle on magnetic and magneto-optic properties in Co/Pt multilayer thin films. which were prepared bye-beam evaporation on tilted substrates. with varying tilt angle from $0^{\circ}$ to $60^{\circ}$. The structure of the specimens was examined by x-ray diffractometer and scanning electron microscope. and the magnetic and magneto-optical properties were measured by VSM, torque magnetometer, and Kerr loop tracer. X-ray diffractometry revealed that all of the specimens had multilayer structure and growth orientation of column followed the tangent rule but the crystallograpic orientation, <111>, was slightly deviated from the substrate normal even though the deposition angle was increased up to $60^{\circ}$. A decrement of the magnetization and Kerr angle with the deposition angle was related with that of the film density due to increasing porosity. The perpendicular mag¬netic anisotropy was also decreased with increasing the deposition angle.

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Arthroscopic Repair of Anterior Root Injury in Lateral Meniscus Using Suture Anchor - Case Report and Technical Note - (Suture anchor를 이용한 외측 반월판 연골 전방 뿌리 파열의 관절경적 치료 -증례 및 술기 보고-)

  • Kim, Do-Young;Yoo, Yon-Sik;Lee, Sang-Soo;Jeong, Un-Seob;Seo, Eun-Min;Park, Seung-Jae
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.10 no.1
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    • pp.41-45
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    • 2011
  • As awareness of root tear of meniscus have been increased, it became necessary to have an intensive repair. Posterior horn tear, especially for a lot of repair methods and the results have been reported recently. The report of the anterior root tear has yet to be found. We recently encountered a patient with an iatrogenic meniscal subluxation caused by past experienced partial menisectomy for discoid meniscus. Thus, we repots the technique and clinical results of arthroscopic repair of subluxated lateral meniscus anterior root tear using suture anchor.

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A Basic Study on Torsion Shear Tests in Soils (흙의 비틀림전단시험에 관한 기초적 연구)

  • 홍원표
    • Geotechnical Engineering
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    • v.4 no.1
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    • pp.17-28
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    • 1988
  • Among several types of element tests to predict soil behalf.iota in a laboratory, the torsion shear apparatus, in which the directions of principal stresses could be rotated during shearing, wra explained. In this study, this torsion shear apparatus was improved so as to be used in tests on clay specimens . And some undrained torsion shear tests u.ere performed on remolded specimens of Ko-consolidated clay to investigate the influence of reorientation of the principal stress directions on the stress-strain behavior The soil behavior by the torsion shear apparatus without torque was compared It.ith that by the conventional triaxial compression tests . The stress path, provided by both vertical loads and torque during torsion shear tests, has much effect on the stress-strain behavior, the pore pressure and the effective principal stress ratio . The rotation angle of the principal stress and the b-value were gradually increased with increasing shear strain, but converged to the values at failure.

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Relative Error Analysis for Measuring Value of Ground Resistance according to Position Variation of Potential Probe) (전위보조전극의 위치변화에 따른 접지저항 측정값의 상대오차분석)

  • Gil, Hyoung-Jun;Kim, Dong-Woo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.2
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    • pp.96-102
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    • 2009
  • In this paper, the effects of the position and the angle of the potential probes on the measurements of the ground resistance with the fall-of-potential method are described and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position and angle of auxiliary probes. In order to analyze the relative error for measuring value of ground resistance due to the position of the potential probe, ground resistance were measured in case that the distance of current probe was fixed at 50[m] and the distance of potential probe was located from l0[m] to 50[m]. Also, the potential probe was located at 30[$^{\circ}$], 45[$^{\circ}$], 60[$^{\circ}$], 90[$^{\circ}$] and 180[$^{\circ}$]. As a consequence, relative error decreased with increasing the distance of potential probe and decreasing the angle between current probe and potential probe. The results could be help to determine the position of potential probe when the ground resistance was measured at grounding system.