• Title/Summary/Keyword: Physical wedge

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Calculation of Diffraction Patterns for Incidence of Planewave on Both Sides of a Dielectric Wedge by Using Multipole Expansion (쇄기형 유전체의 양면에 평면파 입사시 다극전개를 이용한 회절패턴 계산)

  • Kim, Se-Yun;Ra, Jung-Woong;Shin Sang-Yung
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.4
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    • pp.16-26
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    • 1989
  • Diffraction patterns of electromagnetic fields for the incidence of E-polarized plane wave on both interfaces of an arbitrary-angle dielect wedge are obtained by sum of geometric optics term and the edge diffracted fields. The diffraction coefficients of the edge diffracted fields are evaluated by employing the physical optics approximation and then correcting its error with the multipole line source at the dielectric edge. For the wedge angle $120^{circ}$, the incident angle $60^{circ}$, the relative dielectric constant of the dielectric wedge, 2, 5, and 10, and the observation distance from the tip of the wedge, 5 and 10 wavelength, the diffraction coefficients and the diffraction patterns corresponding to geometric optics, physical optics, and the solution corrected by the multipole line source are plotted, respectively. While the corrected solutions presented in this paper are valid only in the far-field region, these asymptotic solutions show to satisfy the boundary condition on the dielectric interfaces.

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The Effects of Femorotibial Angle of Contact laterally Wedged Insoles With Strapping of varying elevations (밀착형 외측 쐐기 스트랩 깔창의 높이에 따라 대퇴경골각에 미치는 영향)

  • Lee, Sang-Yong;Park, Sung-Jin
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.12 no.1
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    • pp.44-50
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    • 2006
  • The purpose of this study is to assess the radiographic effects of normal person with contact laterally wedged insoles with strapping of varying elevations. Eight person who were randomized into group according to their birth dates and wedge elevation, participants wore contact laterally wedged insoles with strapping with elevation of 9, 15, 21mm. Standing radiographs were used to analyze the femorotibial angle for each subject, The result of repeated measures ANOVA's reveled that laterally wedged insoles with strapping of varying elevations produced significantly the femorotibial angle. The degree of change in femorotibial angle with the insole with strapping was effected by the tilt of the lateral wedge(P<0.05). We suggest that these results may be beneficial for manufacturing foot orthotic devices, such as wedged insoles, to control medial and later compartment forces in the knee varus-valgus deformity.

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Study on Effect of KWOMAC of a Contact Lateral-Wedged Insole with Strapping in Patients with Varus Deformity Osteoarthritis of the Knee (내반슬 골관절염 환자에 대한 밀착형 외측 쐐기 스트랩 발받침이 한국형 WOMAC에 미치는 영향에 관한 연구)

  • Lee, Sang-Yang;Gong, Won-Tae
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.13 no.1
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    • pp.26-35
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    • 2007
  • The purpose are to demonstrate the pain, stiffness, and physical function by the Korean Western Ontario MacMaster University(KWOMAC) score of the patients with varus deformity osteoarthritis of the knee after treatment period. Twenty outpatients with knee osteoarthritis(OA) were randomized and divided into the control(n=10) and wedge(n=10) groups. The remission scores of the KWOMAC index of severity for knee OA were compared between the groups. The result of repeated two-way ANOVA's revealed that a contact lateral-wedged insole with strapping produced significantly differences in the pain and physical function score between groups after treatment period(P<0.05), but it was not significant differences in the stiffness score between groups(P>0.05). These results suggest that the pain relief and improvement in function reported by patients with osteoarthritis while using lateral-wedged insole with strapping may be achieved by a reduction in external varus moment and medial compartment load.

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Medpor Craniotomy Gap Wedge Designed to Fill Small Bone Defects along Cranial Bone Flap

  • Goh, Duck-Ho;Kim, Gyoung-Ju;Park, Jae-Chan
    • Journal of Korean Neurosurgical Society
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    • v.46 no.3
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    • pp.195-198
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    • 2009
  • Objective : Medpor porous polyethylene was used to reconstruct small bone defects (gaps and burr holes) along a craniotomy bone flap. The feasibility and cosmetic results were evaluated. Methods : Medpor Craniotomy Gap Wedges, V and T, were designed. The V implant is a 10 cm-long wedge strip, the cross section of which is an isosceles triangle with a 4 mm-long base, making it suitable for gaps less than 4 mm after trimming. Meanwhile, the Medpor T wedge includes a 10 mm-wide thin plate on the top surface of the Medpor V Wedge, making it suitable for gaps wider than 4 mm and burr holes. Sixty-eight pterional craniotomies and 39 superciliary approaches were performed using the implants, and the operative results were evaluated with respect to the cosmetic results and pain or tenderness related to the cranial flap. Results : The small bone defects were eliminated with less than 10 minutes additional operative time. In a physical examination, there were no considerable cosmetic problems regarding to the cranial bone defects, such as a linear depression or dimple in the forehead, anterior temporal hollow, preauricular depression, and parietal burr hole defect. Plus, no patient suffered from any infectious complications. Conclusion : The Medpor Craniotomy Gap Wedge is technically easy to work with for reconstructing small bone defects, such as the bone gaps and burr holes created by a craniotomy, and produces excellent cosmetic results.

Analysis of dual integral equation formulated for EM waves scattered by wedges (쉐기형 산란체에 의해 산란된 전자파에 대한 쌍적분 방정식 해석)

  • Kim, Se-Yun;Na, Jeong-Ung;Sin, Sang-Yeong
    • Proceedings of the KIEE Conference
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    • 1985.07a
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    • pp.344-347
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    • 1985
  • Hew dual integral equation for electromagnetic field scattered by an arbitrary dielectric wedge is formulated. In order to check the validity and physical meaning of the formulated equation, it is applied to the well-known case which is the diffraction by a perfectly conducting wedge.

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Estimated Risk of Radiation Induced Contra Lateral Breast Cancer Following Chest Wall Irradiation by Conformal Wedge Field and Forward Intensity Modulated Radiotherapy Technique for Post-Mastectomy Breast Cancer Patients

  • Athiyaman, Hemalatha;M, Athiyaman;Chougule, Arun;Kumar, HS
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.12
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    • pp.5107-5111
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    • 2016
  • Background: Epidemiological studies have indicated an increasing incidence of radiation induced secondary cancer (SC) in breast cancer patients after radiotherapy (RT), most commonly in the contra-lateral breast (CLB). The present study was conducted to estimate the SC risk in the CLB following 3D conformal radiotherapy techniques (3DCRT) including wedge field and forward intensity modulated radiotherapy (fIMRT) based on the organ equivalent dose (OED). Material and Methods: RT plans treating the chest wall with conformal wedge field and fIMRT plans were created for 30 breast cancer patients. The risks of radiation induced cancer were estimated for the CLB using dose-response models: a linear model, a linear-plateau model and a bell-shaped model with full dose response accounting for fractionated RT on the basis of OED. Results: The plans were found to be ranked quite differently according to the choice of model; calculations based on a linear dose response model fIMRT predict statistically significant lower risk compared to the enhanced dynamic wedge (EDW) technique (p-0.0089) and a non-significant difference between fIMRT and physical wedge (PW) techniques (p-0.054). The widely used plateau dose response model based estimation showed significantly lower SC risk associated with fIMRT technique compared to both wedge field techniques (fIMRT vs EDW p-0.013, fIMRT vs PW p-0.04). The full dose response model showed a non-significant difference between all three techniques in the view of second CLB cancer. Finally the bell shaped model predicted interestingly that PW is associated with significantly higher risk compared to both fIMRT and EDW techniques (fIMRT vs PW p-0.0003, EDW vs PW p-0.0032). Conclusion: In conclusion, the SC risk estimations of the CLB revealed that there is a clear relation between risk associated with wedge field and fIMRT technique depending on the choice of model selected for risk comparison.

The Effects of the Insole Types on Lower Leg Muscle Activity during Treadmill Walking (트레드밀 걷기 동안 인솔형태가 하퇴 근육의 근 활성에 미치는 영향)

  • Park, Jang-Sung;Seo, Sam-Ki;Lee, Sang-Ho;Jung, Hwa-Su;Lim, Jae-Heon
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.8 no.2
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    • pp.33-37
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    • 2010
  • Purpose : We investigated the effects of the insole types on lower leg muscle activation during treadmill walking. The three insole types investigated for this study were normal insole, medial wedge insole, and viscoheel. Methods : Participants were assigned into three groups. People with foot transformation were excluded from this study. Each participant walked for ten minutes. The first day we applied a normal insole. On the second day, a medial wedge insole was applied. Finally, on the last day a viscoheel was applied. After walking on a treadmill for ten minutes, we measured muscle activation in lower leg muscles (gastrocnemius and tibialis anterior). Surface electromyography (EMG) was used to measure muscle activity. The data were analyzed using one-way analysis of variance (ANOVA) with repeated measures to determine the statistical significance. Results : The results of this study were summarized as follows. While walking on the treadmill, root mean square (RMS) values of the gastrocnemius when the viscoheel was applied were significantly lower than the other insole types. There was no significant difference for the RMS values for the tibialis anterior using viscoheel. The normal insole and viscoheel insole were significantly different in a post hoc analysis. However, there was no significant difference for normal insole and medial wedge insole. Conclusion : Using a viscoheel insole decreases muscle activity of the lower leg. Therefore, in conclusion, the viscoheel insole type reduces the load on the lower leg during walking.

Diffraction of Electromagnetic Waves by a Dielectric Wedge, Part II: Correction by Multipole Line Source (쇄기형 유전체에 의한 전자파의 회절, II부 : 다극선전원에 의한 수정)

  • 김세윤;라정웅;신상영
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.8
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    • pp.884-892
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    • 1988
  • An asymptotic solution of electromagnetic waves scattered by an arbitrary-angled dielectric wedge in the E-polarized plane wave incidence is obtained by adding a correction to the physical optical fields given in the previous paper of these companion papers, Part I. The source for the asymptotic correction field valid in the far-field region can be equivalent to the multipole line sources at the tip of the wedge, of which coefficients are evaluated numerically by solving a dual series equation. The corrected field patterns are plotted for the typical case treated in Part I.

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Fast Converging Correction Current for the Physical Optics Edge Diffraction by a dielectric Wedge (유전체 쐐기에 의한 물리광학해를 수정하기 위한 새 로운 급수)

  • 전재영;서종화;나정웅
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.877-880
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    • 1999
  • A rigorous formulation is suggested〔l,2,3〕 in solving the scattering of plane waves by a dielectric wedge. Correcting surface currents are expanded in a Neumann series of fractional orders to meet the edge condition of static limit〔4〕. For the better converging series, the modified Neumann series satisfying the static limit edge condition and the radiation condition are suggested here for the surface currents having two different wave numbers of air and dielectric〔4〕. This representation gives accurate solutions over the whole region including the grazing incidence of the plane waves upon the dielectric wedge of large permittivities.

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Diffraction of Electromagnetic Waves by Right Angle Dielectric Wedge (직각 쐐기형 유전분에 의한 전자파 회절)

  • Ju, Chang-Seong;Ra, Jeong-Ung;Sin, Sang-Yeong
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.18 no.5
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    • pp.35-45
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    • 1981
  • An asymptotic solution of electromagnetic waves scattered by a right-angled dielectric wedge for plane wave incidence is obtained. Scattered fields are constructed by waves reflected and refracted from dielectric interfaces (geometric-optical fields) and a cylindrical wave diffracted from the edge. The edge diffracted field is obtained by adding a correction to the edge diffraction of physical optics approximation, where the correction field is calculated by solving a dual series equation amenable to simple numerical calculation. Validity of this result is assured by two limits of relative dielectric constant $\varepsilon$ of the wedge. The total asymptotic field calculated results in a Rawlins' Neumann series solution for small $\varepsilon$, and the edge diffraction pattern is shown to approach that of a perfectly conducting wedge for large $\varepsilon$. Calculated field patterns are presented and the accuracy of physical optics approximation is discussed.

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