• 한국안광학회지
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• 제20권3호
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• pp.377-384
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• 2015

목적: 본 연구는 이간계인 하워드-돌먼 입체검사와 삼간계로 성인의 동적 입체시를 측정하여 비교해 보고, PD 및 굴절이상과 동적 입체시의 상관성을 분석해 보았다. 방법: 평균연령 $21.27{\pm}2.32$(19~32)세인 성인 93명(남자50, 여자43)을 대상으로 이간계(two-rods test)와 삼간계(three-rods test)로 검사거리 2.5 m에서 동적 입체시를 각각 5회 측정하였다. 결과: 이간계와 삼간계로 측정한 동적 입체시는 각각 전체 평균 $29.91{\pm}23.03$초, $23.75{\pm}21.65$초 였고, 이중 남자는 $28.36{\pm}22.38$초, $22.28{\pm}23.79$초 여자는 $31.71{\pm}23.91$초, $25.46{\pm}19.00$초로 이간계에 비해 삼간계로 측정한 동적 입체시가 모두 좋았으나 통계적으로 유의한 차이는 없었다(p>0.05). PD 평균 표준편차 범위 60.63 mm~66.19 mm 사이의 동적 입체시는 이간계 $31.48{\pm}24.87$초, 삼간계는 $22.54{\pm}17.22초$로 통계적으로 유의한 차이가 있었으나(p<0.05), 두 검사법의 동적 입체시와 PD의 상관성은 크지 않았다. 굴절이상을 기준으로 할 때도 이간계에 비해 삼간계로 측정한 동적입체시가 모두 더 좋게 나타났으나 통계적으로 유의한 차이는 없었고(p>0.05) 굴절이상과 두 동적 입체시간의 상관성도 거의 없었다. 두 입체시는 일반적으로 정상인의 동적 입체시로 간주하는 30~50초 범위에 해당하는 결과가 나타났다. 결론: 삼간계는 이간계보다 입체시가 더 낮게 나타나 동적 입체시의 더 낮은 최소 역치를 측정할 수 있고, 두 검사법이 성인의 동적 입체시 표준검사법으로 사용되고 동적 입체시의 기준을 적용하는데 유용할 것으로 사료된다. PD와 굴절이상은 동적 입체시에 큰 영향을 주지 않는 것으로 나타났다.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.107-112
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• 2011

Multiple ground rods are commonly used to obtain the low ground impedance, but they will not reduce the ground impedance unless the spacings between the ground rods are sufficient. This paper presents the experimental results of frequency-dependent resultant ground impedance of two ground rods in parallel. The resultant ground impedance of two ground rods in parallel were measured as functions of the spacing and length of ground rods and the frequency of test currents and were discussed based on the potential interferences. As a consequence, the frequency-dependent ground impedance of single ground rod and two combined ground rods give capacitive. It was found that the effect of potential interference on the ground impedance is directly associated with the frequency-dependent ground impedance and is strong in low frequency. Also, in order to reduce the increasing rate of resultant ground impedance of two ground rods due to potential interference to within 10(%), two ground rods in parallel will be placed over one rod length apart.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.297-300
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• 2005

The bond characteristics of GFRP(glass fiber reinforced polymer) rods with various surface deformation produced by RTM(resin transfer molding) process were analyzes experimentally. Two types of GFRP rods with different surface deformation manufactured by RTM process in domestic area and two types of GFRP rebars imported were considered in this study. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the CSA S806-02 recommendations. From the test results, it was found that deformed-type GFRP rod manufactured by RTM process showed the highest bond strength among test specimen. But, wave-type GFRP rod made by RTM process show the lowest value due to the splitting failure of concrete caused by the wedge action of waved surfaces on GFRP rods.

• 한국공간구조학회논문집
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• 제15권4호
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• pp.91-98
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• 2015

This paper has proposed a reinforcing method for damaged RC columns with SRF sheets and Aramid rods. In order to verify the effectiveness and performance, two original columns and two reinforced columns with SRF sheets and Aramid rods were developed and tested under lateral cyclic displacement and a constant axial load. The test showed that the improvement of energy dissipation capacity was increased in terms of strength and ductility. In addition, an analytical modeling of the standard specimens was proposed using Response-2000 and ZeusNL program. The results of analytical and experimental studies for two standard columns were compared in terms of loading-displacement curve and energy dissipation capacity based on the nonlinear static analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1858-1860
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• 2003

Ground rods as the discharge path are commonly installed to ensure the safety of human beings and facilities from the surge. Accordingly, proper grounding resistance are specified by the grounding types, and the specified resistance are also required to install the lightning protective facilities. it is needed to analyze the difference between these two resistance through the field test. Therefore, in this paper, the impulse response behavior of the ground rods is analyzed by constructing the test facilities and by testing the ground rods in multi-ground power distribution systems. The impulse responses were analyzed, in transient state, by testing the concrete poles as well since the grounding wires are installed in the concrete poles.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.293-296
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• 2005

The tensile properties of GFRP(glass fiber reinforced polymer) rods with various surface deformation produced by RTM(resin transfer molding) process were analyzes experimentally. Two types of GFRP rods with different surface deformation manufactured by RTM process in domestic area and two types of GFRP rods imported were considered in this study. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the ASTM D3916-02 recommendations. From the test results, it was found that wave-type GFRP rod made by RTM process showed the highest tensile strength due to the highest fiber volume ratio.

• 한국지반공학회지:지반
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• 제12권5호
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• pp.55-62
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• 1996

Lateral loading model tests were performed on the rigid box-shaped cellular bulkhead by displacement-controlled method. The materials of ground and fill used in this study are two aluminium rods with different sections. The behalf·iotas of ground and fill were recorded by photo/video techniques and failure mechanism created in ground and fill has been simulated two-야mensionally. Also the theoretical consideration about the test results was done on the basis of Hansen's earth pressure theory. As a result, the shape of sliding face the location of sliding face and the loading height was also investigated.

• 한국공간구조학회논문집
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• 제15권1호
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• pp.57-64
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• 2015

This paper shows the test results of continuous reinforced concrete beams with external post-tensioning rods. Six three-span beams were prepared and tested to fail. Three beams were designed to have flexure-dominating behavior and the others to have shear-critical behavior. In each group, one beam without external post-tensioning rods was designated as a control beam and two beams had the external post-tensioning rods of 18 mm or 22 mm diameter. External post-tensioning rods were installed within an interior span of 6000 mm. They show V-shaped configuration because two anchorages were located at the top of interior supports and a saddle pin at mid-span was installed at the bottom of the beam. Test results show that the load and shear capacities of strengthened beams were increased when compared with the control beam. Additionally, the measured shear strength was compared with the strength predicted by ACI 318-11 code equations. The detailed ACI 318-11 equation predicted the measured shear strength and failure location of the continuous beam reasonably well.

• Structural Engineering and Mechanics
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• 제5권4호
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• pp.339-353
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• 1997

Fiber reinforced plastic (FRP) rods provide certain benefits over steel as concrete reinforcement, such as corrosion resistance, magnetic and electrical insulation, light weight, and high strength. FRP composites can be combined with a steel core to form hybrid reinforcing rods that take advantage of properties of both materials. The objective of this study was to characterize the bond behavior of hybrid FRP rods made with braided epoxy-impregnated aramid or poly-vinyl alcohol FRP skins. Eleven rod types were tested using two concrete strengths. Specific topics examined were bond strength, slip, and type of failure in concentric pull-out tests from concrete cubes. From analysis of identical pull-out tests on both hybrid and steel rods, information on relative bond strength and behavior were obtained. It is concluded that strength is similar but slip in hybrid rods is much higher. Hybrid rods failed either by pull-out or splitting the concrete block (with or without yielding of the steel core). Experimental data showed consistency with similar test results presented in the literature.

• 한국소음진동공학회논문집
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• 제22권7호
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• pp.619-625
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• 2012

Since the fuel is always exposed to turbulent flow, the grid strap shows flow induced vibration characteristics that impact on the nuclear fuel soundness. The dynamic behavior of grids in nuclear fuels is quite complex, since two pairs of spring and dimple support are contacted with rods by friction in the limited space. This paper focuses on investigation of the grid strap(test fuel strap, TFS) vibration in one cell. TFS consists of a single spring and double dimples. To identify the grid strap vibration, modal analysis of the strap is performed using finite element method(FEM). Modal testing on a $5{\times}5$ grid structure without rods is performed. The modal testing results are compared to analytic results. In addition, random test considering rod effect is performed about a $5{\times}5$ grid with rods under real contact condition in the air. Finally, the strap vibration of a $5{\times}5$ fuel bundle in investigation of flow induced vibration(INFINIT) facility is measured in real fluid velocity condition without heating. It is shown that modal frequencies from the test are almost equal to those peak frequencies in the INFINIT test.