• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.40.2-40.2
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• 2010

It has been reported that geosynchronous magnetopause crossings are more frequently observed in the prenoon sector than in the postnoon sector, indicating a dawn-dusk magnetopause asymmetry during extreme solar wind conditions. Motivated by these observations, we investigate geosynchronous magnetic field variations normalized to SYM-H when sudden commencements (SC) are observed on the ground. From a statistical analysis of the geosynchronous magnetic field responses to SC events from 1997 to 2006, we found that the normalized SC amplitude at geosynchronous orbit is larger in the morning sector than in the afternoon sector. In order to examine if this morning-afternoon asymmetry at geosynchronous orbit occurs only during disturbed geomagnetic conditions, we compared the geosynchronous magnetic field strength obtained in the morning and afternoon during undisturbed intervals (Kp < 3). We found that the asymmetry appears under undisturbed geomagnetic conditions and it is not due to solar wind aberration. This indicates that the morning-afternoon asymmetry was not strongly affected by changes in solar wind condition. Using solar wind data, we discuss what causes the morning-afternoon asymmetry at geosynchronous orbit.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.288-291
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• 2004

The characteristics of the buckling analysis module for stiffened composite structures were studied in this paper. Composite stiffened structures have geometrical asymmetry and material properties asymmetry. Due to these reason, postbuckling analysis was essential and the characteristics of postbuckling analysis modules for ABAQUS were researched. Static analysis module was considered. By considering the material nonlinearity, progressive failure mechanism was applied and buckling strength was estimated

• 천문학회지
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• 제50권4호
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• pp.105-109
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• 2017

The well-known solar cycle controls almost the entire appearance of the solar photosphere. We therefore presume that the continuous emission of visible light from the solar surface follows the solar cyclic variation. In this study, we examine the solar cyclic variation of photospheric brightness in the visible range using solar images taken by the Solar and Heliospheric Observatory (SOHO)/Michelson Doppler Imager (MDI). The photospheric brightness in the visible range is quantified via the relative intensity acquired from in the raw solar images. In contrast to total solar irradiance, the relative intensity is out of phase with the solar cycle. During the solar minimum of solar cycles 23-24, the relative intensity shows enhanced heliolatitudinal asymmetry due to a positive asymmetry of the sunspot number. This result can be explained by the strength of the solar magnetic field that controls the strength of convection, implying that the emission in the visible range is controlled by the strength of convection. This agrees with the photospheric brightness increasing during a period of long spotless days.

• The Journal of Korean Physical Therapy
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• 제16권4호
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• pp.38-58
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• 2004

The regain of independent ambulatory ability is a important goal in the rehabilitation program of hemiplegic patient. Not only the function of lower extremity muscles, but also trunk muscles which stabilize extremities and pelvis, are important factors in normal gait. Therefor, it is necessary to develop an effective program which can improve muscle strength and symmetric activity of trunk muscles. The purpose of this study was to evaluate the influence of trunk muscle strengthening by forceful respiratory exercise on the gait asymmetry ratio in hemiplegic patient. 45 Hemiplegic patients due to stroke was randomized in 3 groups, forceful expiratory training(FET), forceful inspiratory training(FIT) and control group. In the experimental groups, ordinary physical therapy with forceful expiratory training and forceful inspiratory training for 20 minutes duration 3 times per week for 6 weeks were respectively performed. In the control group, only ordinary physical therapy was done. Before and after experiments, temporal-spatial gait parameters was measured in all patients. The data of 28 patients who carried out the whole experimental course were statistically analysed. The results of these experiment are as follows : 1. In comparison of difference of single support time asymmetry ratio among 3 groups, the FET group was significantly decreased than the control group (p<.05). 2. In comparison of difference of step length asymmetry ratio among 3 groups, the FIT group was significantly decreased than the control group (p<.05). Based on these results, it is concluded that the forced respiratory exercise program for 6 weeks can be improve the gait asymmetry ratio in hemiplegic patients. Therefore, the forced respiratory exercise is useful to improve the walking ability in hemiplegic patients. Since this study dealt only with the patients who could walk more than 3 meters in distance on floor independently, the further study for evaluating the influence of the forceful respiratory exercise on patients with acute stage stroke and also the development in various methods of use are expected.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.699-702
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• 2002

A DC current sensor is disclosed in which two pairs of saturable cores are provided so as enclose a conductor carrying a direct current to be measured. On each of the saturable cores, a bias winding, a feedback winding and an output winding are wound. Circuit for detection of an asymmetry in the magnetization current, generated by a reference alternating voltage, in a signal-conditioner. The reference alternating voltage is fed to the respective series circuits such that no resultant induction current is induced in the modulating current. The voltages over the resistor form input signals for two peak value detectors, the strength of the output signal of which represents the degree of asymmetry of magnetization current. This paper describes the development a DC current sensor and its signal-conditioner.

• 소성∙가공
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• 제26권6호
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• pp.333-340
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• 2017

The cyclic hardening behavior of transformation-induced plasticity (TRIP) steels shows tension-compression asymmetry known to be attributed to transformation of retained austenite into martensite during deformation. In this work, YoshidaUemori hardening model was used to represent the asymmetric hardening behavior of TRIP1180 steel. Yoshida-Uemori hardening model parameters were obtained from three sets of data: tension-compression, compression-tension, and a combination of the two. Material models were validated for U-bending and springback.

• 한국터널지하공간학회 논문집
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• 제9권4호
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• pp.387-401
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• 2007

최근 용지매입의 제한, 주변 구조물과의 간섭 등으로 두 터널의 이격거리가 매우 작은 근접 병설터널의 시공이 증가하고 있다. 이러한 경우 터널의 안정성뿐만 아니라 중앙 필라부의 안정성 확보를 위한 보강공법의 선정은 매우 중요한 문제라 할 수 있다. 본 연구에서는 상 하행선의 터널단면이 다른 비대칭 형태이면서, 두 터널간의 이격거리가 매우 근접한 병설터널에 대한 안정성 평가 및 필라부 보강방안에 대하여 상세한 해석적 검토를 수행하였다. 또한 근접 병설터널의 안정성을 확보할 수 있도록 암반 필라의 안정성 검토와 보강공법 등 근접 병설터널의 사례연구를 토대로 보강공법의 적정성과 합리적인 대안을 제시하였다. 특히, 굴착순서, 이격거리, 굴착방법에 따른 터널 거동 파악을 위하여 암반 필라의 응력상태 및 터널변위를 분석하여 암반파괴이론에 근거한 안정성 평가를 수행하였다. 또한 암반 필라부 보강공법의 적정성 검토 및 향후 근접병설 터널에서의 암반 필라 안정성 확보를 위한 개선방안을 제안하였다

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권1호
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• pp.21-36
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• 2018

The incidence of collision damage models on oil tanker and bulk carrier reliability is investigated considering the IACS deterministic model against GOALDS/IMO database statistics for collision events, substantiating the probabilistic model. Statistical properties of hull girder residual strength are determined by Monte Carlo simulation, based on random generation of damage dimensions and a modified form of incremental-iterative method, to account for neutral axis rotation and equilibrium of horizontal bending moment, due to cross-section asymmetry after collision events. Reliability analysis is performed, to investigate the incidence of collision penetration depth and height statistical properties on hull girder sagging/hogging failure probabilities. Besides, the incidence of corrosion on hull girder residual strength and reliability is also discussed, focussing on gross, hull girder net and local net scantlings, respectively. The ISSC double hull oil tanker and single side bulk carrier, assumed as test cases in the ISSC 2012 report, are taken as reference ships.

• 대한통합의학회지
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• 제12권2호
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• pp.47-53
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• 2024

Purpose : This study investigated the effects of concentric and eccentric contractions on muscle strength using an isokinetic dynamometer (ID) in college students in their 20s. It aimed to understand the impact of differences between the dominant and non-dominant sides on strength asymmetry and to elucidate the clinical implications of these differences to establish an appropriate posture and environment for patients. Methods : The experiment was conducted with 30 healthy adult participants. Prior to the experiment, participants underwent a warm-up targeting the shoulders, and efforts were made to eliminate factors that could potentially influence the measurement results. Subsequently, the maximum safe range of motion of shoulder joint abduction, extension, and flexion was measured using an isokinetic muscle function testing device. Muscle strength was assessed using concentric and eccentric contractions alternating between the dominant and non-dominant sides, and paired sample t-tests were used for the analysis. Results : There was no significant difference between bilateral peak torques for eccentric contraction in shoulder joint abduction, extension, and flexion (p>0.05). There was also no significant difference between bilateral peak torques for concentric contraction in shoulder joint abduction, extension and flexion (p>0.05). Conclusion : This study found no statistically significant difference in muscle strength between the dominant and non-dominant sides during concentric and eccentric contractions. However, previous studies have shown significant differences between the dominant and non-dominant sides during eccentric and concentric contractions during internal shoulder rotation in the general population, as well as significant differences in the upper trapezius muscle. Therefore, further research is needed to support the application of different intensities for bilateral muscle strengthening exercises in clinical practice.

• Carbon letters
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• 제16권4호
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• pp.241-246
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• 2015

Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, −15°/+15°, −30°/+30°, −45°/+45°, and −90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.