• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.231-233
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• 2001

Axial magnetic field(AMF) type electrodes can be increase the interrupting capability of vacuum interrupters. Depending on the design, the principle of the local axial magnetic field arrangement are different. In this paper, a new AMF contact design based on a unipolar field arrangement and its characteristics are introduced. The influence of the unipolar AMF on the arc behavior is described by high-speed video camera. In addition, three-dimensional AMF simulations have been peformed by means of a finite element analysis(FEM) program to analyze the influence of magnetic field distribution on the AMF performance. The high interrupting capability of the unipolar AMF type electrode has been confirmed by three-phase test.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.57-64
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• 2001

There are some previous reports that some animals such as rats and birds move in a large group and act abnormally to avoid the large earthquake. This study is to experimentally testify what relations exist between the anomalous animal behavior and electric field effect, which is reported due to the piezoelectric effects in a basement rock before earthquake occurrences. When electric field is applied to the whole bottom of the cage, they show nervous behaviors such as grooming, washing their faces, standing on legs or running around in panic to avoid the electric field. When more strong electric field is applied, they jump with shrieking and mount on the electric line. The rat shows more sensitive anomalous behavior than the bird. Even though the current to the experimental birds and rats is just a few $\mu$A, they react in various ways. The anomalous animal behaviors under the small ground electric field may have some relations to the actual phenomena before great earthquake. This kind of study is quite worthy for the understanding of earthquake precursors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.820-823
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• 2002

The asymptotic problem of a semi-infinite conducting crack parallel to the poling direction in ferroelectric ceramics subjected to electric fields is analyzed. The main mechanism for the conducting crack growth behavior is thought to be ferroelectric domain switching leading to the development of a process zone around the crack. The shape and size of the switching zone is shown to depend strongly on the relative magnitude on the ratio of the coercive electric field to the yield electric field. It is shown that the crack growth can be either enhanced or retarded depending on the ratio of the coercive electric field to yield electric field.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.128-135
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• 1997

The indirect boundary integral equation is formulated to analyze the behavior of a cavity in a multilayered half-plane subjected to earthquake waves. This formulation uses the fundamental solutions that are numerically calculated by the generalized transmission and reflection coefficient method. The free surface of the cavity without external excitation influences the behavior of the half-plane. Consequently this analysis adds the consideration of scattering-field into the analysis and the total motion field of the cavity is decomposed into the free-field and scattering-field motions. The free-field motion is obtained from the modification of the transmission and reflection coefficient method. The scattering-field motion is calculated is calculated by the indirect boundary value problem which has the ficticious boundaries and sources. In this study, P wave, SV wave, SH wave, and Rayleigh wave are analyzed respectively.

• 한국학교ㆍ지역보건교육학회지
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• 제15권1호
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• pp.121-140
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• 2014

Objectives: Recently, the rate of death by chronic disease, is increasing steadily. To prevent this, the public health center will have taken a leading role in the local community medical business through an establish to the national health promotion act and an amendment to the law of public health center in Korea. Results: Accordingly this research, using the Pender's health promotion model which is related with subject health behavior who government employees serve at the public health center have taken important position in the local community health promotion, have comprehended the actual condition of health behavior. For increasing the health behavior practice of subject to comprehend the factor which have effect on health behavior practice, which can be a correct role model in the local community health promotion. A survey was performed on 406 government employees who serve at five public health centers in Seoul. The period of survey was from 25th October, 2010 to 15th November, 2010. The results of this study were summarized as below. 1. Work-related stress, perceptible beneficial obstacle, and self-efficacy were composed by 5 points measure. The results show those work-related stress were $3.06{\pm}0.469$, 74perceptible beneficial obstacle were $3.74{\pm}0.471$, and self-efficacy were $3.49{\pm}0.469$. 2. As for the health behavior by general characteristic, the results have specific differences on age, education level, state of marriage, rank of the position, field of the occupation and employment forms in statics analysis. 3. As for the past health behavior by health behavior characteristic, work-related stress have specific differences on the past frequency of drinking (p<.05) in statics analysis, perceptible beneficial obstacle have specific differences on the past frequency of having breakfast(p<.05), having snacks(p<.05) and doing exercise(p<.05) in statics analysis. Self-efficacy have specific difference on the past frequency drinking(p<.01) in statics analysis. 4. According to the correlation between the factors related with health behavior and health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). Work-related stress and self-efficacy don't have specific relation in health behavior practice. 5. The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations. The ability of explanation occupied 54.8% what explained of the health behavior practice by general characteristic, perceptible health condition, employment forms and perceptible beneficial obstacle. Conclusions: According to the correlation between the factors related with health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations.

• 한국정밀공학회지
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• 제21권6호
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• pp.109-116
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• 2004

In this study, when variable-amplitude load with various applying mode acts on the pre-crack tip, we examined how fatigue cracks behave. Hence aspects of the deformation caused by changing the applying mode of single overload and propagation behavior of fatigue crack were experimentally examined: What kinds of the deformation would be formed at pre-crack and its tip\ulcorner What aspects of the residual plastic deformation field would be formed in front of a crack\ulcorner How aspects of the plastic zone could be evaluated\ulcorner As applying mode of single overloading changes, the deformation caused by tensile and shear loading variously showed in each applying mode. The different aspects of deformation make influence on propagation behavior of cracks under constant-amplitude fatigue loading after overloading with various modes. We tried to examine the relationship between aspects of deformation and fatigue behavior by comparing the observed deformation at crack and crack propagation behavior obtained from fatigue tests.

• 한국초전도ㆍ저온공학회논문지
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• 제8권4호
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• pp.26-29
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• 2006

The study to be presented related on initial behavior of quench concerned with many considerations, such as epoxy impregnated coil, critical current density related on strain and temperature, winding effect and behavior of internal superconducting wire. Especially, the deformation behavior of coils under magnetic field and thermal contractions at cryogenic temperatures to be dealt with the analytical method related on Fracture Mechanics. From the results, we know that the strain by self weight contribute to epoxy cracking at the edge of deformed coils and the deformation behavior relate on epoxy cracking must be dealt with biaxial loading problem. Then, the epoxy crack on $r\theta-plane$ under biaxial loading have been propagated with inclined crack angle and joined superconducting wire. Also, we can explain transfer of epoxy crack propagation energy from epoxy resin to superconducting wire.

• 한국농공학회논문집
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• 제52권4호
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• pp.45-52
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• 2010

The purposes of this research are to analyze the internal settlement behavior of Concrete Faced Rockfill Dam (CFRD) typed 'D dam' and to evaluate the stability of the 'D dam' during dam construction using internal settlement measurements and results of numerical analysis. The field measurements were obtained during dam construction period. The numerical analysis was also carried out for the same construction period. The numerical analysis focused mainly on prediction of stress and displacement behavior of 'D dam' during dam construction stage using input parameters obtained from laboratory tests, i.e. large triaxial tests. The behavior of 'D dam' was evaluated to be stable from comparing the results of field measurements and numerical analysis. A simple empirical equation is also presented to predict final settlement at the completion of dam construction, using settlement measurement monitored during dam embankment.

• Smart Structures and Systems
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• 제15권6호
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• pp.1411-1437
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• 2015

The electro-magneto- thermo-elastic behavior of a rotating functionally graded long hollow cylinder with functionally graded piezoelectric (FGPM) layers is analytically analyzed. The layers are imperfectly bonded to its inner and outer surfaces. The hybrid cylinder is placed in a constant magnetic field subjected to a thermo-electro-mechanical loading and could be rested on a Winkler-type elastic foundation. The material properties of the FGM cylinder and radially polarized FGPM layers are assumed to be graded in the radial direction according to the power law. The hybrid cylinder is rotating about its axis at a constant angular velocity. The governing equations are solved analytically and then stresses, displacement and electric potential distribution are calculated. Numerical examples are given to illustrate the effects of material in-homogeneity, magnetic field, elastic foundation, applied voltage, imperfect interface and thermo-mechanical boundary condition on the static behavior of a FG smart cylinder.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1089-1094
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• 2004

Numerical methods to estimate behaviors of jointed rock mass can be roughly divided into two method : discontinuous model and continuum model. Generally, distinct element method (DEM) is applied in discontinuous model, and finite element method (FEM) or finite difference method (FDM) is utilized in continuum model. To predict a behavior of discontinuous model by DEM, it is essential to understand characteristics of joints developed in rock mass through field tests. However, results of field tests can not provide full information about rock mass because field tests is conducted in limited area. In this paper, discontinuous analysis by UDEC and continuous analysis by FLAC is utilized to estimate a behavior of a tunnel in jointed rock mass. For including discontinuous analysis in continuous analysis, joints in rock mass is considered by reducing rock mass properties obtained by RMR and decreasing shear strength of rock mass. By comparing and revising two analysis results, analysis results similar with practical behavior of a tunnel can be induced and appropriate support system is decided.