• 설비공학논문집
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• 제15권2호
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• pp.109-115
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• 2003

The performance of two vertical-blade eliminators (V1, V2) and two horizontal-blade ones (H1, H2) for absorption chillers were tested in terms of pressure drop and refrigerant entrainment. The test was carried out using a wind tunnel with a cross section of 300 mm$\times$300 mm. The pressure drop of four eliminators tested was found to be in the rage of 1.0~2.7mm $H_2O$ at the face velocity of 2m/s. In the refrigerant entrainment test the vertical-blade eliminators showed much better performance than the horizontal-blade ones. The horizontal-blade eliminators showed satisfactory results at the air velocity of 2m/s but exceeded the limit value at 3 m/s. Since the cooling capacity of a machine is lowered by about 2.5% at the pressure drop of 1 m $H_2O$, more researches are required to reduce the pressure drop in the eliminator.

• 국제물리치료학회지
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• 제10권4호
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• pp.1903-1906
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• 2019

Background: Foot drop is a common symptom after stroke and causes walking disorders. Therefore, its proper treatment is important for improving the walking ability of patients with foot drop. Objective: This study aimed to investigate the effects of electrostimulation during walking on the walking ability of patients with foot drop after stroke. Design: Quasi-experial study. Methods: The study enrolled 18 patients with foot drop after stroke. All subjects were assigned to the experimental or control group. The experimental group underwent electric stimulation during walking, while the control group used ankle foot orthoses. Both groups received treatment 20 minutes a day 5 times a week for 4 weeks. Outcome measures were assessed for walking and balance ability using the 10-m walking test (10MWT), 6-min walking test (6MWT), and Timed Up and Go test (TUG) Results: After the intervention, both groups showed significant improvements in 6MWT and TUG results. However, the experimental group showed significantly better improvement on all tests than the control group. Conclusion: The foot drop stimulator effectively improved the walking and balance ability of patients with foot drop after stroke.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.158-163
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• 2008

Muffler design in the exhaust system is critical to provide for low noise in shipboard spaces. In an attempt to effectively design the low noise muffler, it is important to evaluate the performance of the muffler considering not only the noise, but also pressure drop as well. For this purpose, a test system of large exhaust muffler for ship propulsion systems was designed based on ISO 7235. The substitution test for determining both the insertion loss and pressure drop of mufflers was carried out. A ship exhaust muffler is considered as a test example and the insertion loss and pressure drop are obtained.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1237-1242
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• 2008

A muffler design in the exhaust system is critical to provide fur low noise in shipboard spaces. In an attempt to effectively design the low noise muffler, it Is important to evaluate the performance of the muffler considering not only the noise, but also pressure drop as well. For this purpose, a test system of large exhaust mufflers fur ship propulsion systems was designed based on ISO 7235. The substitution test fur determining both the insertion loss and pressure drop of mufflers was carried out. A ship exhaust muffler is considered as a test example and the insertion loss and pressure drop were obtained.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.30-37
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• 2008

The evaporation pressure drop of $CO_2$ (R-744) in horizontal tubes was investigated experimentally. The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator (test section). The test section consists of a smooth, horizontal stainless steel tube of 7.75 and 4.57 mm inner diameter. The experiments were conducted at saturation temperature of $-5^{\circ}C\;to\;5^{\circ}C$, and heat flux of 10 to $40kW/m^2$. The test results showed the evaporation pressure drop of $CO_2$ are highly dependent on the vapor quality, heat flux and saturation temperature. The pressure drop measured during the evaporation process of $CO_2$ increases with increased mass flux, and decreases as the saturation temperature increased. The evaporation pressure drop of $CO_2$ is very lower than that of R-22. In comparison with test results and existing correlations, the best fit of the present experimental data is obtained with the correlation of Choi et al. But existing correlations failed to predict the evaporation pressure drop of $CO_2$. Therefore, it is necessary to develop reliable and accurate predictions determining the evaporation pressure drop of $CO_2$ in a horizontal tube.

• 에너지공학
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• 제21권1호
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• pp.26-32
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• 2012

본 연구에서는 PV(photovoltaic)모듈에서 경년에 따른 효율 저하의 원인을 분석하기 위해 셀 레벨에서의 열충격 시험을 수행하였다. 열충격 시험의 조건은 $-40^{\circ}C$에서 $85^{\circ}C$로 각각 15분씩 30분을 1사이클로 하였으며, 열충격 시험 500 사이클 동안 100 사이클 간격으로 EL분석 및 I-V분석을 수행하였다. 효율 감소율은 단결정 Bare Cell이 8%, Solar Cell이 9%였으며, 다결정 Bare Cell이 6%, Solar Cell이 13%의 감소율을 보였다. 열충격 시험 후 Solar Cell은 표면 손상으로 인한 효율저하를 확인할 수 있었다. Bare Cell의 경우 표면의 손상이 없었지만, 효율이 저하된 것을 확인할 수 있었다. 이는 Fill Factor 분석에 의해 경년 시 나타나는 누설전류에 의한 소모전력 증가로 효율 저하에 영향을 준 것으로 판단된다. 또한, Bare Cell보다 Solar Cell에서의 효율 감소율이 상대적으로 높게 나타난 결과는 표면 손상 및 소모 전력의 증가로 인해 Solar Cell 효율에 큰 영향을 미치는 것으로 판단된다. 향후 단면 분석법 및 다양한 조건의 시험 기법을 활용하여 PV모듈 뿐 아니라 Cell 레벨에서의 불규칙한 효율 및 Fill Factor의 감소 원인을 검토하고, Solar Cell에서의 효율 저하가 가속되는 원인에 대한 대책 방안 연구가 수행되어야 할 것이다.

• 한국포장학회지
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• 제15권3호
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• pp.77-81
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• 2009

음료와 맥주 제품의 경우 신선도를 유지하기 목적으로 다양한 종류의 유리병이 국내에서 생산되거나 수입되어 유통되고 있다. 실제 트럭으로 국내 운송되는 맥주 유리병 제품의 유통환경에서 진동 특성을 분석하고 이를 바탕으로 트럭 불규칙 진동 특성인 0.52 $G_{rms}$을 진동시험 규격으로 적용하여 예측실험을 실시하였으며, 결론적으로 유리병의 자체의 파손은 관측되지 않았다. 트럭의 적재함 위치별 상하진동 수준에 있어서는 뒷부분에 위치한 가속도계에서 가장 큰 진동 특성(0.17 $G_{rms}$)이 나타났으며, 앞 부분(0.11 $G_{rms}$)과 중간 부분(0.12 $G_{rms}$)은 큰 차이를 보이지 않았다. 낙하 높이와 제품 용량의 종류에 관계없이 바닥면으로 낙하된 유리병의 경우 파손은 관측되지 않았다. 단측면 낙하 시 가장 큰 유리병 파손율을 보였으며, 장측면에 비해 약 2배 높은 유리병 파손율을 나타내었다.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.922-929
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• 2019

This paper presents the drop performance test of the control rod assembly which is one of the main components strongly related to the safety of the prototype generation IV sodium-cooled fast reactor. To investigate the drop performance, a real-sized control rod assembly that was recently modified based on the drop analysis results was newly fabricated, and several free drop tests under different flow rate conditions were carried out. Then the results were compared with those obtained from the previous tests conducted on the conceptually designed control rod assembly to demonstrate the improvement in performance. Moreover, the drop performance tests under several types and magnitudes of seismic loadings were also conducted to investigate the effect of the seismic loading on the drop performance of the modified control rod assembly. The results showed that the effects of the type and magnitude of the seismic loading on the drop performance of the modified control rod assembly were not significant. Also, the drop time requirement was successfully satisfied, even under the seismic loading conditions.

• The Journal of Korean Physical Therapy
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• 제31권3호
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• pp.147-150
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• 2019

Purpose: The purpose of this study was to compare the reliability of unilateral hip abductor strength assessment in side-lying with break and make test in subjects with pelvic drop. Hip abduction muscles are very important in the hip joint structures. Therefore, it is essential to evaluate their strength in a reliable way. Methods: Twenty-five subjects participated in this study. Unilateral isometric hip abductor muscle strength was measured in side-lying, with use of a specialized tensiometer using smart KEMA system for make test, of a hand held dynamometer for break test. Coefficients of variation, and intra class correlation coefficients were calculated to determine test-retest reliability of hip abductor strength. Results: In make test, maximal hip abductor strength in the side-lying position was significantly higher compared with break test (p<0.05). Additionally, Test-retest reliability of hip abductor strength measurements in terms of coefficients of variation (3.7% for make test, 16.1% for break test) was better in the side-lying position with make test. All intraclass correlation coefficients with break test were lower than make test (0.90 for make test, 0.73 for break test). Conclusion: The side-lying body position with make test offers more reliable assessment of unilateral hip abductor strength than the same position with break test. Make test in side-lying can be recommended for reliable measurement of hip abductor strength in subjects with pelvic drop.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 추계 학술대회 논문집
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• pp.339-347
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• 2005

IP-2형 운반용기는 정상운반조건의 낙하시험을 거친 후에 방사성내용물의 유실 또는 분산이 없고 외부표면에서의 방사선량률이 $20\%$ 이상 증가할 수 있는 차폐능력의 상실이 없어야 한다. 차폐체의 두께가 큰 경우에는, 볼트체결방식을 사용하면 IP형 운반용기로 많이 사용되고 있는 ISO 컨테이너에서의 문을 사용하는 경우보다 방사성내용물의 유실 또는 분산이 일어나지 않을 것이다. 본 연구에서는 볼트체결방식의 IP-2형 운반용기에 대한 낙하시험을 실시하기 전에, 낙하방향에 따른 볼트인장력과 볼트체결력을 시험으로 평가하는 방법을 알아보기 위하여 예비시험모델을 제작하여 시험 및 평가하였다. 바닥과 뚜껑방향의 수직낙하, 수평낙하, 4방향의 경사낙하 등 총 7가지 낙하방향으로 자유낙하를 실시하였다. 낙하충격에 의한 볼트인장력은 힘센서를 이용하여 측정하였고, 볼트체결력은 낙하시험 전의 체결토르크에서 낙하충격 이후의 풀림토르크의 변화를 이용하여 알아보았다.