• Proceedings of the KIEE Conference
• /
• 1986.07a
• /
• pp.591-594
• /
• 1986

An asymptotic solution of electro-magnetic waves diffracted by a dielectric wedge of the angle larger than $180^{\circ}$ is obtained in case of the incidence of a E-polarized plane wave. Based on the dual integral equation in the spectral domain, physical optics approximation is supplemented by correction currents distributed along the interfaces. Those currents are expanded in a series of Bessel functions, known as Neumann's expansion of which fractional order is chosen to satisfy the static edge condition as the limiting value of dynamic case. Numerical results of edge diffraction patterns and field patterns are presented for some typical cases.

• Journal of the Society of Naval Architects of Korea
• /
• v.54 no.4
• /
• pp.321-328
• /
• 2017

In practice, cavitation phenomena occur in unbounded flows. However, the wall effect is unavoidable during experiments at a closed section such as a cavitation tunnel. Especially, supercavity generated behind a cavitator is relatively large and thick, so that geometric and dynamic characteristics of the cavity are affected by the tunnel wall. In order to apply experimental results into the unbounded flow field, physical correlations are necessary. In this paper, we proposed an image method based on a potential flow to simulate the wall effect. Considering two-dimensional wedge-shaped bodies, configurations and drag characteristics of the cavity were examined according to the distance ratio to the wall surface. The results were compared and verified with existing theoretical and experimental results.

• Physical Therapy Korea
• /
• v.2 no.2
• /
• pp.56-65
• /
• 1995

The purpose of this study was to compare the effects of one proprioceptive neuromuscular facilitation technique and static stretching on calf muscle tightness. The subjects consist of 9 hemiplegics, and 9 quadriplegics. The eighteen subjects were randomly divided into 3 groups: prorioceptive neuromuscular facilitation(6 persons), static stretching(6 persons) and control(6 persons). Contract relax antagonist contract and static stretching techniques were applied continuously for twenty minutes each. Of the many proprioceptive neuromuscular facilitation techniques, only the contract relax antagonist contract technique was applied. The static stretching technique was applied with the subject placed in standing on a seventy degree inclined tilt table for twenty minutes. A wedge was placed under the feet to obtain maximum dorsiflexion. Wedge thickness varied with each subject. Results revealed: (1) a significant difference between the experimental and the control groups(p<0.05). (2) a significant difference between contract relax antagonist contract and static stretching groups(p<0.05). (3) At day five, the final increments were: contract relax antagonist contract $11.9{\pm}1.90^{\circ}$, static stretching $7.7{\pm}2.3^{\circ}$(mean${\pm}$standard deviation).

• Journal of Korean Physical Therapy Science
• /
• v.18 no.4
• /
• pp.59-64
• /
• 2011

Purpose : The purpose of this study was to evaluate the effects of the stretching of the calf muscles on foot pressure and contact area in young adult. Participants stood on a wedge board that was sloped between 15~25 degree for 15min. After stretching participants stood quietly on force plate, result was recorded. Participants stood on a force plate for 1 min in eye closed condition, and them the foot pressure and area was recorded. The following variables were calculated off-line: anterior and posterior foot pressure and contact area, medial and lateral foot pressure and contact area. Results showed that anterior pressure change due to stretch, but mediolateral was not significant. This result suggested that stretching of the calf muscle has the effect of increasing anterior pressure by flexibility change on calf muscle, so this effects might be effective intervention for reduce of serious problem to neurologic patients in therapy session.

• 한국해양학회지
• /
• v.25 no.2
• /
• pp.62-73
• /
• 1990

An experimental study is performed in order to catch the characteristics of the flow field at arrested salt wedge, using a rectangular open channel. Arrested salt wedge is generally so stable that the observations are easy, but velocities and interfacial waves are measured with the aid of visualization method, by injection of fluorescent dyes. The density interface, which is defined as the zone of maximum density variation with depth, exists in about 0.5 cm below the visual interface, and vertical density profile is quite well satisfied with Homeborn model. Interfacial layer has high turbulent intensity and its thickness decreases as the overall Richardson number increases and has magnitude of roughly 17% of upper layer. Cross-sectional velocity distribution just shows the influence of a side-wall friction and in the upper layer vertical velocity profile also becomes uniformly as Reynolds number increases, but in the lower layer it shows nearly parabolic type. Supposes that we divide salt wedge into three domains, that is, river mouth, intermediate and tip zone, entertainment coefficient is small at the intermediate zone and large at the river mouth and the tip zone. River mouth or intermediate zone has comparatively stable interface and capillary wave therefore s produced and propagated downstream. On the other hand, tip zone is very unstable, cusping ripple or bursting ripple is then produced incessantly. Arrested salt wedge form is nearly linear and has no relation to densimetric Froude number and Reynolds number.

• Korean Journal of Applied Biomechanics
• /
• v.13 no.3
• /
• pp.133-149
• /
• 2003

The purposes of present study were to determine the major check-points of golf swing from the review of previous studies, and to suggest additional information on the teaching theory of golf. The golf swing motion of 6 male and female elite university golf players were filmed with 16mm Locam II high speed cameras at the speed of 200f/s, and variables such as time, displacement, angle, velocity were calculated and analyzed by 3D Cinematography using DLT method. The results were: 1. Differences were shown in the ratio of weight distribution on the feet, cocking angle, take-back velocity, club-head velocity at impact depending upon the physical characteristics and club used for swing. 2. Time for the down-swing and impact were $0.27{\sim}0.29s$ in men and $0.29{\sim}0.32s$ in women, which was 1/3 of the time for the back-swing. Women showed longer total swing time than men because of longer time in back-swing, follow-through and finish. 3. Men showed larger range of motion in shoulder and knee joints than women, on the other hand women showed larger range of motion in hip joint than men. 4. Cocking motion and right elbow flexion were occurred at the top of back-swing and cocking release was occurred at the moment of impact. Maximum rotations of shoulder and hip joints were found between the top of back-swing and down-swing phase. 5. Women showed lower back-swing velocity than men, and men showed higher club velocity(men: $38.2{\sim}38.6m/s$, women: $35.1{\sim}36.4m/s$) than women.

• Progress in Medical Physics
• /
• v.9 no.2
• /
• pp.105-113
• /
• 1998

Accurate radiation dosimetric characters is very important to determine of dose to a radiotherapeutic patient. Medical linear accelerators have been developed not only its new quality of convenient operation but also electric moderation. It is reliable to measure more detail physical parameter that linac's internal ability. Typically, radiation dosimetric tool is classified ionization chamber, film, thermoluminescence dosimeter, etc. Nowaday, Electronic Portal Imaging Device is smeared in radiation field to verification of treatment region. EPID's image was focused that using both on-line image verification and absolutely minimum absorbed dose during radiotherapy. So, Electronic Portal Imaging was tested for quality evaluation of medical linear accelerator had its pure conditional flash. This study has performed symmetry, Light/Radiation field congruence, and energy check, geometry difference on wedge filter using a liquid filled ion chamber (EPID). Prior to irradiated on EPID, high energy photon beam is checked with ion chamber. Using these results more convenient dosimetric method is accomplished by EPID that taken digital image. Medical image is acquired with EPID too. Therefore, EPID can be analyzed by numerical information for what want to see or get more knowledge for natural human condition.

• Journal of The Geomorphological Association of Korea
• /
• v.24 no.3
• /
• pp.27-45
• /
• 2017

At the upper part of terrace deposits at Jeongdongjin area, there is a structure in which reddish brown and grayish white layers laying horizontally. Previous studies have reported the existence of these structures within the deposits and suggested the theoretical background related to the formation process. However, the analysis of physical properties and chemical composition such as particle size, classification, etc. of the materials constituting the reddish brown and grayish white layers is scarcely done. In this study, the physico - chemical properties of gray - white and reddish brown beds are investigated. The mean grain size of the particles was less than $4{\varphi}$ in both layers and the reddish brown layer was more coarse. The results shows that the sorting of the grayish white layer is better. The chemical composition of both layers shows that the average concentration of $SiO_2$, $Al_2O_3$ and $K_2O$ of the grayish white layer was higher than those of the reddish brown layer. The concentration of $Fe_2O_3$ of reddish brown lyaer was 3 times higher than those of the grayish white layer. The degree of chemical weathering (CIA) is 90 or so in both the reddish brown and grayish white layers, indicating a significant level of chemical weathering. In conclusion, reddish brown layers had been formed by the processes related to the migration of iron and the migration of water that induced aggregation after the formation of sediments (psudo-gleization). In this study area, a vertical layer of grayish white which cuts off horizontal reddish brown and grayish white color was found. The vertical layer or wedge similar to a ice-wedge or columnar structure that in a cold environment, and there is a difference in shape and size. The vertical layer appears to have occurred three or more cycles. The vertical layers begin to form at a certain height within the outcrop and descend downwards, which of course is difficult to see as directing certain times.

• Journal of computational fluids engineering
• /
• v.19 no.2
• /
• pp.40-48
• /
• 2014

For rarefied gas flow regimes, physical phenomena such as velocity slip and temperature jump occur on the solid body surface. To predict these phenomena accurately, either the Navier-Stokes solver with a slip boundary condition or the direct simulation Monte Carlo method should be used. In the present study, flow simulations of a wedge were conducted in Mach-10 flow of argon gas for several different flow regimes using a two-dimensional Navier-Stokes solver with the Maxwell slip boundary condition. The results of the simulations were compared with those of the direct simulation Monte Carlo method to assess the present method. It was found that the values of the velocity slip and the temperature jump predicted increase as the Knudsen number increases. Also, the results are comparatively reasonable up to the Knudsen number of 0.05.

• Archives of Plastic Surgery
• /
• v.36 no.6
• /
• pp.779-783
• /
• 2009

Purpose: Male hypertrophic nipples can lead to psychological distress and physical discomfort. The authors present a new technique of male nipple reduction and describe its advantages Methods: The neonipple is designed to reduce diameter and height of nipple while preserving the subdermal plexus. After the central wedge excision, additional four triangular section of nipple skin is excised. One of the remaining two flaps is amputated partially and both flaps were approximated using 4 - 0 PDS and 6 - 0 Nylon sutures. Results: Between December of 2007 and January of 2009, 52 nipple reductions were performed in 30 male patients(mean = 29.5 years). Postoperative recovery was rapid and few complications were encountered. The mean diameter of the hypertrophic nipple was $9.1{\pm}2.5mm$(range, 7 to 15 mm). The mean diameter of the neonipple was $5.0{\pm}0.7mm$(range, 4 to 6 mm), with an average reduction of $3.8{\pm}0.6mm$(range, 2 to 11 mm). At follow-up, the neonipple had a natural appearance, with less projection and an inconspicuous scar. Conclusion: The wedge and triangular skin excision and partial amputation are easy to perform and yields consistent results. This technique decreases both the diameter and height of any size nipple and can be modified to meet patient preferences.