• 대한지역사회작업치료학회지
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• 제1권1호
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• pp.41-47
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• 2011

목적 : 본 연구는 수예공작 프로그램을 이용하여 자폐아동과 지적장애아동의 시지각 효과를 비교함으로써 그 필요성을 밝히고자 한다. 연구방법 : 선정기준에 따라 자폐아동 10명, 지적장애 아동 10명을 선별한 후 시지각 프로그램을 적용하였다. 사용된 수예공작 프로그램은 수예공작을 치료로 적용하고 있거나 적용한 경험이 있는 전문가에 의해 의뢰되고 만들어졌다. 항목에 들어가는 것은 도예작업, 모빌공예작업, 밀가루 반죽작업, 지점토작업, 골판지공예작업, 칼라믹스작업이 선택되었다. 이 프로그램은 4주 동안 일주일에 두 번 적용하였고, 치료 전후의 효과를 확인하기 위해 MVPT-3를 사용하였다. 결과 : 첫째, 수예공작 프로그램이 자폐아동과 지적장애아동 모두 효과가 있었다. 둘째, 수예공작 프로그램 적용 후 각각을 비교하였을 때, 지적장애아동에게 더 높은 효과가 있었다. 결론 : 수예공작 프로그램이 자폐아동과 지적장애아동의 시지각 기능 발달에 영향을 미친다는 것을 알 수 있었다.

• 산업기술연구
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• 제33권A호
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• pp.23-30
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• 2013

Tidal power generation is to produce electrical energy from fluctuations of the ebb and flow in a constructed embankment. More specifically, the sinusoidal variations of tidal flow, along with the periodicity and changes in the height of waves over time make the tidal power generation possible at a certain tidal level. This paper proposes a more practical efficiency test method for tidal power plant generator that utilizes the axis torque changing values rather than the retardation method which is commonly used. The proposed method was compared with the conventional method and the test result shows that proposed method provides a similar accuracy with the conventional retardation method and a better efficiency.

• 한국군사과학기술학회지
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• 제5권4호
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• pp.67-77
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• 2002

This paper introduces the calibration results of the fatigue crack growth models for damage tolerance analysis of the aircraft structures. Generalized Willenborg model and Wheeler model are calibrated with experimental data tested under the load spectrum of a trainer. The retardation factors such as, shut-off ratio in Generalized Willenborg model and shaping exponent in Wheeler model, are evaluated for aluminum alloys AL2024-T3511, AL7050-T7451 and AL7075-T73511. It is shown that the retardation effect of the crack growth rate depends on the yield strength of material and the maximum stress in the load spectrum. Generalized Willenborg model and Wheeler model give satisfactory prediction of crack growth life but the calibration of the experimental parameters with test is required.

• 한국군사과학기술학회지
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• 제4권2호
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• pp.42-51
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• 2001

The effects of pre-indentation technique are presented for A12024-T3 Alclad alloy using as skin material for aircraft fuselage and wing. Indentations were applied to specimens to be placed on the presumed path of fatigue crack growth before fatigue tests. Tension-tension fatigue tests were conducted on the edge cracked specimens in the L-T orientation. Test results were analyzed to investigate the effectiveness of pre-indentation with the variation of specimen's thickness, position of indentation and applied maximum stress. Fatigue crack retardation by pre-indentation is well recognized in the various conditions.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.629-636
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• 2003

The retardation of heavy metals in a mixture of fly ash and bentonite was studied as a potential barrier material for a landfill. Column tests were conducted using synthetic leachate having 100 mg/L and 50 mg/L of lead (Pb) and cadmium (Cd), respectively. Results indicated that the mixture had obvious retardation ability for heavy metals. To investigate the retardation factor caused by adsorption, batch adsorption tests were conducted at various concentrations. Test results were correlated with both Langmuir and Freundlich isotherms. The adsorption of the lead ion was applicable to the Langmuir isotherm and the adsorption of the cadmium ion was applicable to the Freundlich isotherm. In addition, based on experimental results, the migration characteristics of heavy metals through the bed of fly ash and bentonite mixture were investigated using the PHREEQC, a reactive transport model, under the real conditions of the landfill liner.

• 전자공학회논문지D
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• 제34D권7호
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• pp.62-70
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• 1997

In this paper, the optical conditins of a reflective multi-color STN-LCD based on electrical control of birefringence is designed on the poincare sphere. First of all, the angles of polarizer and analyzer for the best color purity are decided in the configuration without a retardation film. A retardation film is introduced for a bright white in the range of the applied voltage. The sretardation and the angle of the retardation film are also decided on the poincare shpere. The test cell is farbricated and its measured spectral transmittance and the CIE chromaticity diagram agree well with simulations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.854-858
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• 2002

In this study, Fatigue crack growth behavior of the laser welded sheet metal due to a single overload was investigated. From Fatigue crack propagation test, it was observed that the retardation of fatigue crack growth has been more effective in the welded specimen than in the base metal. And if the distance between the welded part and the position of overload is too close the retardation of fatigue crack growth at the welded part has been decreased. From FEM analysis, it was observed the retardation has been more effective compressive residual stress than plastic zone.

• 대한기계학회논문집
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• 제14권5호
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• pp.1193-1199
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• 1990

본 연구에서는 가공경화지수 (n)가 서로 다른 몇가지 재료를 선택하고 과대하 중의 비 (%PL)를 달리하는 단일 과대하중 피로 시험을 행하여 재료의 가공경화지수가 피로 균열 진파의 지연거동에 미치는 영향과 아울러 균열닫힘현상과의 관계를 구명하였다.

• 한국안전학회지
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• 제7권2호
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• pp.47-56
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• 1992

The retardation effect of fatigue crack propagation after cyclic overloading seems to be affected by strain hardening exponent. Namely, for the material with high values of n, the delay effect is found to be severe. We proposed a modified crack retardation equation which may apply the retardation of fatigue crack growth after a cyclic overloading, as (da/dN)'$_{cyc}$=($\mu$n＋λ)B $\Delta$ $K^{q}$ /[(1－ $R_{eff}$) $K_{cf}$ －$\Delta$K]. where, $R_{eff}$ is effective stress ratio [＝( $K_{min}$－K, os)/( $K_{max}$－ $K_{res}$)] The constants $\mu$＝－0.5 and λ＝0.6, and the values are found to be identical for materials such as aluminum (A 1060), steel (SS 34), brass ( $B_{s}$ SIB) and stainless steel (SUS 304) used in this investigation. (SUS 304) used in this investigation.ation.n.n.

• 대한조선학회논문집
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• 제40권3호
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• pp.45-53
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• 2003

Ships and ocean structures are subjected to random loads caused by irregular waves. The irregularity of amplitude from random loading affects on fatigue crack growth and fatigue life. However the effects of irregularity of loading on fatigue including random loading have not been explained exactly. Therefore in this paper crack growth tests on DENT specimens under constant-amplitude loading including a single tensile overload are conducted to investigate the effect of overload on crack growth rate. The size of plastic zone and crack growth rate before and after a single tensile overloading are measured using ESPI system. Crack growth retardation model that is characterized by crack growth length and the size of plastic zone was proposed and compared with test result. From the research, the validity of proposed model is examined on crack growth retardation, and consequently fatigue life.