• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.362-370
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• 2001

We prove that 3-D profile mapping using white light interferometry has systematic errors caused by aberrations of the optimal system. The tilt of an object invokes an offset between the object and the reference ray, which eventually makes the aberration cancel incompletely. The fringe peak of a white light interferogram is mainly affected by the aberration effect while the envelope peak remains stable. By the difference between the two peaks, it is easily confirmed how much the error existed in the fringe peak. Experimental results prove that the error caused by aberration is varied by object tilt, microscope NA, optics alignment within the range of $\pm$50nm.

• Korean Journal of Optics and Photonics
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• v.26 no.2
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• pp.115-120
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• 2015

Explicit expressions are derived for the effective reflection coefficients of obliquely incident light on a multilayered substrate coated with two uniaxially anisotropic films. Based on these reflection coefficients, ellipsometric constants are obtained as function of the tilt and azimuthal angles of the optical axes of the uniaxial films. Explicit expressions are provided, which can be used to separate the effects of surface anisotropy for anisotropic film from that of its bulk anisotropy, so that these expressions may be utilized in characterizing the surface anisotropy of alignment layers.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1587-1592
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• 2021

The effects of the symmetrical tilt Σ5 (310) <001> grain boundary (GB) on the evolution of radiation-induced point defects in pure δ-plutonium (Pu) were studied by Molecular dynamics (MD) simulations. The evolution of radiation-induced point defects was obtained when primary knock-on atom (PKA) was respectively set as -15 Å and 15 Å far from the GB and the number of residual defects was obtained as the distance from PKA to GB was changed. According to the results, compared with vacancies, interstitial atoms were more easily absorbed by GB. In addition, the formation energy of point defects was also calculated. The results showed that there was almost no difference for the formation energy of vacancies in the all matrix. However, the formation energy of interstitial atoms close to the GB was lower than that in the other bulk regions.

• International Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.79-82
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• 2015

The handicap for investigating the aero-optical effect focuses on the accurate prediction on the index refraction fluctuation or density fluctuation. In recent years, with the development of CFD techniques and optical experimental techniques, the comprehension have developed on the aero-optical transmitting effect in many kinds of complex flow. This study mainly introduces the optical aberration in compressible mixing layer. And then the debates about the mechanism of aero-optical effects and assessment of image blur also present.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.197-209
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• 2018

In this study, numerical analyses on Quad Tilt Rotor(QTR) are carried out to investigate the interference effect of components and effect of operating condition during forward flight. Actuator Surface Method(ASM) which is implemented in an open source CFD code, OpenFOAM, is used to calculate the flow field around QTR with high computational efficiency. The lift of the front and rear wing is found to increase or decrease depending on the rotation direction of the rotor. At the rear wing, the interference effects of the front and rear rotor appear as a combined manner. Performance change due to the phase difference is found to be insignificant. For both rotors, the locally higher thrust is generated by the blockage effect of the wing. The interference effect of wake from the front nacelle contributes to higher local thrust for the rear rotor compared to the front rotor. And it is observed that the amplitude of thrust oscillation can decrease depending on the phase difference between the rotors. Aerodynamic performances of both rotors and the entire aircraft were compared and analyzed for various operating conditions.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.1-10
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• 2014

PURPOSE: The purpose of this study was to investigate the effects of flexible derotator of femur orthosis (FDO) during treadmill gait training on the quadriceps-angle (Q-angle), lateral pelvic tilt, gait speed, and number of steps in children with cerebral palsy. METHODS: Seven children with cerebral palsy who had rotational deformity of the lower extremities participated in this study. We used single group repeated measure design. The procedure consisted of baseline phase, intervention phase, and post-intervention phase. The baseline phase consisted of stretching and strengthening exercise and treadmill gait training without FDO. The treatment phase not only included the same procedures as those for baseline, but also included FDO during treadmill gait training. Postural alignment of the lower extremities was assessed with the Q-angle, and lateral pelvic tilt using the Dartfish software program. A 10-m walk test was used to evaluate gait speed and number of steps. RESULTS: For postural alignment, there was significant differences after the application of FDO (p<.05). For gait ability, there was significant differences in all phases (p<.01). CONCLUSION: These finding suggest that the application of FDO during treadmill gait training had a positive effect on the improvement of postural alignment and gait ability in children with cerebral palsy having rotational deformity.

• PNF and Movement
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• v.19 no.3
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• pp.303-310
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• 2021

Purpose: The purpose of the present study was to investigate the effects of the contact-relax (CR) intervention on pelvic alignment in subjects with habitual poor posture. Methods: Fifteen subjects who have habitual poor posture participated in this study. The subjects received an intervention inducing pelvic posterior depression with the elevated pelvic side. Pre- and post-intervention, and two weeks after intervention, the pelvic alignment was measured with a palpation meter (PALM) and a three-dimensional diagnostic imaging system. Results: Measuring with PALM, the pelvic height and anterior tilt angle were significantly decreased immediately after and were still decreased two weeks after intervention, compared to the pre-measurement (p<0.05). Three-dimensional pelvic alignment was also significantly different between measurement points, while the pelvic position (pelvic lateral tilt) was significantly decreased after intervention (p<0.05). Conclusion: By applying the intervention generating CR on an elevated pelvis, frontal pelvic alignment can be improved.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.314.1-314.1
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• 2014

The properties of Ni/Au Ohmic contacts formed on nonpolar a-plane GaN grown on r-plane sapphire substrate with different tilt angles are investigated using current-voltage (I-V) measurements. To investigate the effects of pattern direction and size on Ohmic contact properties of a-plane GaN, transmission line method (TLM) patterns are formed either along c-axis and m-axis on nonpolar GaN surface with different size. I-V measurement results show that the size of TLM pattern and formation direction of electrode have an effect on the electrical properties of a-plane GaN. The large sized patterns show the relatively lower sheet resistance compared to the small sized patterns. In addition, the sheet resistance of a-plane GaN along m-axis shows lower values than that along the c-axis. Finally, the effects of miscut angle of r-sapphire substrate ($0.2^{\circ}$, 0.4oand $0.6^{\circ}$) on electrical properties of a-plane GaN will be discussed.

• Journal of Korean Vacuum Science & Technology
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• v.1 no.1
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• pp.1-12
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• 1997

A new three-dimensional (3D) Monte Carlo ion implantation simulator, TRICSI, has been developed to investigate 3D mask effects in the typical mask structure for ion implantation into crystalline silicon. We present the mask corner and mask size effects of implanted boron range profiles, and also show the calculated damage distributions by applying the modified Kinchin-Pease equation in the single-crystal silicon target. The simulator calculates accurately and efficiently the implanted-boron range profiles under the relatively large implanted area, using a newly developed search algorithm for the collision partner in the single-crystal silicon. All of the typical implant parameters such as dose, tilt and rotation angles, in addition to energy can be used for the 3D simulation of ion implantation.

• 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.