• 한국의류산업학회지
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• 제8권4호
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• pp.441-448
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• 2006

This research is the hair damage as treating a permanent wave before and after that is compared and analyzed the change of physical and mechanical properties. This is the survey of women's hair in 20 years old. On the basis of this we would like to analyze a extend of hair damage. Also, we would to show a basic data for hair damage prevention and hair improvement to keep the beautiful and healthy hair. The conclusion is as follow. : The swelling degree after the treatment was found to be greater than before permanent wave treatment. For the formational characteristics wave, untreated hair certainly had more elastic S curl wave than damaged hair in all the permanent wave treatments, and damaged hair and extremely damaged hair had less elasticity and had saggy S curl wave. The protein permanent and soft permanent wave had thicker, gorgeous, and better elastic wave than the regular permanent wave and direct heating permanent wave in all the hair condition. As the degree of damage on hair got greater, the tensile strength dramatically decreased and as the degree of damage got greater, the elongation was great as well. For treatment method, direct heating permanent wave showed the greatest effect, causing the most damage.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1221-1229
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• 2022

In this work, the guided wave de-bonding area-detecting technique was studied for application to containment liner plates in nuclear power plant areas. To apply this technique, an appropriate Lamb wave mode, symmetric and longitudinal dominance, was verified by the frequency shifting technique. The S0 2.7 MHz mm Lamb wave mode was chosen to realize quantitative experimental results and their visualization. Results of the bulk wave, longitudinal wave mode, and comparison experiments indicate that the wave mode was able to distinguish between the de-bonded and bonded areas. Similar to the bulk wave cases, the bonded region could be distinguished from the de-bonded region using the Lamb wave approach. The Lamb wave technique results showed significant correlation to the de-bonding area. As the de-bonding area increased, the Lamb wave energy attenuation effect decreased, which was a prominent factor in the realization of quantitative tomographic visualization. The feasibility of tomographic visualization was studied via the application of Lamb waves. The reconstruction algorithm for the probabilistic inspection of damage (RAPID) technique was applied to the containment liner plate to verify and visualize the de-bonding condition. The results obtained using the tomography image indicated that the Lamb wave-based RAPID algorithm was capable of delineating debonding areas.

• 한국해안·해양공학회논문집
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• 제35권2호
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• pp.33-40
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• 2023

월파량은 항만구조물의 마루높이 산정 및 구조물 배후 시설물의 활용 등과 관련된 중요한 설계요소이다. 본 연구에서는 상대적으로 급한 전면 경사수심에 설치된 직립식 호안의 월파량 산정에 대한 수리실험을 수행하였다. 급한 경사면의 수심을 가지는 동해안의 대상 해역 2곳을 선정한 후 각각을 단면수로에 재현하였다. 각각의 대상해역별로 다양한 수심 및 파랑 조건에 대하여 월파량을 계측하였다. 특히 충격파 조건에 대한 월파량 산정결과를 기존 연구성과와 비교하였으며, 유사한 월파량 분포 경향이 나타나는 것을 알 수 있었다. 실험결과를 통해 직립식 구조물의 경우에는 전면 경사의 영향이 매우 큰 것을 알 수 있었으며, 향후 EurOtop 등의 적용시 이에 대한 검토가 필요할 것이다.

• Computational Structural Engineering : An International Journal
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• 제2권1호
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• pp.33-42
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• 2002

A computationally efficient stiffness design method for building structures is proposed in which dynamic soil-structure interaction based on the wave-propagation theory is taken into account. A sway-rocking shear building model with appropriate ground impedances derived from the cone models due to Meek and Wolf (1994) is used as a simplified design model. Two representative models, i.e. a structure on a homogeneous half-space ground and a structure on a soil layer on rigid rock, are considered. Super-structure stiffness satisfying a desired stiffness performance condition are determined via an inverse problem formulation for a prescribed ground-surface response spectrum. It is shown through a simple yet reasonably accurate model that the ground conditions, e.g. homogeneous half-space or soil layer on rigid rock (frequency-dependence of impedance functions), ground properties (shear wave velocity), depth of surface ground, have extensive influence on the super-structure design.

• 대한조선학회논문집
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• 제56권5호
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• pp.418-426
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• 2019

To derive a simplified analytic solution which can be utilized as a fundamental solution for the wave maker design, a segment of the wave board has been idealized as a submerged line segment in a two dimensional domain of a wave flume. The lower end of the line segment could be located at arbitrary depth of the wave flume and the upper end of the board could be also submerged to any depth from the free surface. The freely oscillating motion of the wave board is assumed to be defined by determining the condition of horizontal oscillation on both ends differently. The submerged wave board oscillating in horizontal direction could be specified by selecting the amplitude, frequency and the phase lag differently on lower and upper ends of the board. The simplified two dimensional wave generated by the wave board segment has been obtained by the first order perturbation method. It is found that the general solution of the freely oscillating wave board in two dimensional domain could be decomposed into the solution of flap motion with lower end hinge and swing motion with upper end hinge. The case study of the analytic solutions has been carried out to evaluate the effect on the wave height due to the difference of oscillation frequency, phase difference and variation of stroke between for the motion of both ends. It is found that the solution of the freely oscillating wave board could be utilized for the development of high performance wavemaker especially for irregular waves.

• 한국해양공학회지
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• 제2권2호
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• pp.27-36
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• 1988

For the purposes of drilling oil field and extracting oil deep water in more rough weather, the size of drilling rigs must be estimated. In this paper, the three dimensional source distribution method is used and we assume 10 deg. heeling and trimming condition of the drilling rig(SR-192). Also, the effects of the hydrodynamic forces which include the drift forces for field method, and the motion responses are studied with changing the incident wave direction in the assumed inclining condition. The theory and numerical codes used in this thesis appeared to be very useful for the preliminary design of drilling rigs.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.81-84
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• 1989

EHZP is a kind of holographic optical element, which is generated by the interference of two divergent spherical waves from point sources on the same axis. It has the spherical aberration that the focal power increases as the radial distance r increases. By using this property, optimal design of EHZP was performed for f-$\theta$ lens. As the result of optimization, the f-$\theta$ condition and the field flattening condition were well satisfied when EHZP has f0=0.803f, faR=4.076f, 1=0.406f. It was assumed for calculation of field flattening condition that the incident wave was a plane wave with the diameter of 1mm.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.29-40
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• 2006

The paper presents an optimization system which integrates a parametric design tool, 3D diffraction-radiation analysis and hydrodynamic performance assessment based on short and long term wave statistics. Controlled by formal optimization strategies the system is able to design offshore structure hulls with superior seakeeping qualities. The parametric modeling tool enables the designer to specify the geometric characteristics of the design from displacement over principal dimensions down to local shape properties. The computer generates the hull form and passes it on to the hydrodynamic analysis, which computes response amplitude operators (RAOs) for forces and motions. Combining the RAOs with short and long-term wave statistics provides a realistic assessment of the quality of the design. The optimization algorithm changes selected shape parameters in order to minimize forces and motions, thus increasing availability and safety of the system. Constraints ensure that only feasible designs with sufficient stability in operation and survival condition are generated. As an example the optimization study of a semisubmersible is discussed. It illustrates how offshore structures can be optimized for a specific target area of operation.

• 대한조선학회지
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• 제17권1호
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• pp.19-24
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• 1980

From the singularity distribution which obtained by minimum wave resistance condition, optimum hull form is obtained by stream line trancing method as Inui and Pien did. Thus obtained hull form has a extruded bottom along a keel line. Therefore the hull form must be modified to have flat bottom. This modification process is conducted by putting a fictitious bottom. It is found out that the wave resistance does not significantly alter at design speed even though the hull form has remarkably changed at the bottom. Therefore flattening the bottom by the effect of depth may be more rational for practical hull form design than ordinary manual hull-form modification.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2000년도 춘계 학술대회 및 국제 감성공학 심포지움 논문집 Proceeding of the 2000 Spring Conference of KOSES and International Sensibility Ergonomics Symposium
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• pp.86-90
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• 2000

The effects of the timing of daily bathing on sleep in winter were studied. Eight healthy male subjects were assigned to three sleep conditions: bathing just before sleeping (Condition J), bathing 2 h before sleeping (Condition T0 and no bathing before sleeping (Control). We can found that slow wave sleep and REM sleep were increased, and sleep onset latency and wake after sleep onset were shortened in Condition T compared with Condition J. Rectal and mean skin temperatures n both bathing conditions were the same levels after the first half of sleep. Furthermore, subjective sleep sensation was the highest value in Condition T. These results suggest that bathing done before going to bed in winter was good for sleep; moreover, bathing 2 h before going to bed was more effective than bathing immediately before going to bed.