• 한국추진공학회지
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• 제25권6호
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• pp.60-65
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• 2021

본 논문에서는 추진기관에 충전된 추진제의 알루미늄의 조성 불균일에 따른 추진제의 점화 가능성을 확인하고자 하였다. 추진제 내부의 알루미늄의 불균일한 분포를 모사하기 위해 알루미늄 함량을 14~20%까지 임의로 변경하여 충격감도, 마찰감도 시험을 수행하였다. 충격감도를 측정한 결과 50% 기폭 에너지 및 최소 기폭 에너지는 알루미늄 함량과 무관하게 50 J 부근의 값을 가진다. 이는 알루미늄 함량이 증가하여도 충격 자극에 추진제가 민감해지지 않는다는 것을 의미한다. 반면에 마찰감도 결과에서는 알루미늄 함량이 증가할수록 50% 기폭힘과 최소 기폭힘이 감소하여 추진제가 민감해지는 것을 알 수 있었다. 이는 추진제 발화 시의 "Hot Spot" 모델에 따라 충격 자극보다 마찰 자극에 의해 추진제 내부의 공간이 순간적으로 압축이 되어 발화가 되는 것으로 추정된다.

• 소음진동
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• 제1권2호
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• pp.115-120
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• 1991

The impact hammer is extensively used in experimental modal analysis as a means to provide force over a broad range of frequencies. The hammer mass and the impact head are often changed to achieve a desired impact time duration with its corresponding input frequency spectrum, these mass changes affect the performance and sensitivity of the force transducer employed to measure the impact force. Both a mathematical model describing the effects of impact head and hammer mass on the performance of the force transducer and experimental verification of this model are presented here.

• 한국농공학회논문집
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• 제63권6호
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• pp.141-150
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• 2021

In order to assess the impact of climate change on irrigation reservoirs, climate exposure (EI), sensitivity (SI), and potential impact (PI) were evaluated for 1,651 reservoirs nationwide. Climate exposure and sensitivity by each reservoir were calculated using data collected from 2011 to 2020 for seven proxy variables (e.g. annual rainfall) and six proxy variables (e.g. irrigation days), respectively. The potential impact was calculated as the weighted sum of climate exposure and sensitivity, and was classified into four levels: 'Low (PI<0.4)', 'Medium (PI<0.6)', 'High (PI<0.8)', and 'Critical (PI≥0.8)'. The result showed that both the climate exposure index and the sensitivity index were on average high in Daegu and Gyeongbuk with high temperature and low rainfall. About 79.8% of irrigation reservoirs in Daegu, Gyeongbuk, and Ulsan with high climate exposure and sensitivity resulted in a 'High' level of potential impact. On the contrary, 64.5% of the study reservoirs in Gyeongnam and Gangwon showed 'Low' in potential impact. In further studies, it is required to reorganize the proxy variables and the weights in accordance with practical alternatives for improving adaptive capacity to drought, and it is expected to contribute to establishing a framework for vulnerability assessment of an irrigation reservoir.

• 한국기계가공학회지
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• 제21권5호
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• pp.16-21
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• 2022

This study investigates the effect of the deformation on the sensitivity of a flexible polydimethylsiloxane (PDMS) membrane sensor. A PDMS membrane sensor was developed to measure the impact force of a water droplet using a silver nanowire (AgNW). The initial deformation of the membrane was confirmed with the application of a tensile force (i.e., tension) and fixing force (i.e., compressive force) at the gripers, which affects the sensitivity. The experimental results show that as the tension applied to the membrane increased, the sensitivity of the sensor decreased. The initial electrical resistance increased as the fixing force increased, while the sensitivity of the sensor decreased as the initial resistance increased. The movement of the membrane due to the impact force of the water droplet was observed with a high-speed camera, and was correlated with the measured sensor signal. The analysis of the motion of the membrane and droplets after collision confirmed the periodic movement of not only the membrane but also the change in the height of the droplet.

• The Journal of Asian Finance, Economics and Business
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• 제9권2호
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• pp.185-191
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• 2022

The purpose of this research is to see if liquidity, non-performing assets, sensitivity, and efficiency have an impact on the profitability and capital of Indonesian state-owned banks. A random sample of public banks was used in this study. The data was collected from the first quarter of 2014 to the fourth quarter of 2019. Purposive sampling was used as the sampling technique. According to the findings of this study, liquidity (LDR) had a significant positive effect on capital but had no significant effect on profitability. Productive asset quality as proxied by the ACA and NPL ratios did not affect profitability or capital. As for the sensitivity ratio, which was proxied by the ratio of NOP and IRR, there were differences in behavior. Sensitivity had no significant impact on profitability or capital, while NOP had a significant positive impact on capital but not on profitability. In terms of efficiency, both OER and FBIR had a significant effect on profitability and capital, although in different directions. OER has a significant negative impact on both profitability and capital. Fee-based income (FBIR) had a significant positive impact on capital, but it had the opposite effect on profitability.

• 한국음향학회지
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• 제37권6호
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• pp.428-436
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• 2018

소음에 대한 반응은 응답자의 소음 민감도에 따라 차이가 발생될 수 있다. 본 연구에서는 소음 민감도와 함께 층간소음에 대한 거슬림, 생활방해, 이웃에 대한 의견 등을 조사하였다. 설문조사 응답자를 소음 민감도 그룹별로 구분하고 소음 민감도 그룹별 층간소음의 거슬림, 생활방해 등에 대하여 비교하였다. 이를 통해 소음 민감도 설문조사 방법을 제시하였다. 설문조사는 서울, 경기 지역 공동주택 거주경험자 233명을 대상으로 층간소음에 의한 거슬림, 생활방해와 소음 민감도, 이웃에 대한 의견과 층간소음 발생 시 항의 방법에 대하여 조사하였다. 설문조사 결과 민감도 그룹을 3개로 나눈 경우 소음 민감도가 높은 그룹의 층간소음 거슬림과 생활방해 반응이 나머지 그룹과 유의한 차이가 있는 것으로 나타났다. 이웃에 대한 느낌 조사 결과 연령대가 증가함에 따라 이웃에 대한 긍정적 반응이 증가되는 것으로 조사되었다. 또한 이웃에 대해 긍정적 느낌을 갖는 그룹의 층간소음 거슬림, 생활방해 인식도 낮은 것으로 나타났다.

• 소성∙가공
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• 제12권8호
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• pp.693-701
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• 2003

In this paper, the influence of frictional conditions on the backward impact extrusion of aluminum battery casing with large aspect ratio has been investigated. In the simulation, MSC.Superforge, a package based on the finite volume method, is used for the extrusion analysis. The formability and earing problem during the production have been evaluated by studying the sensitivity to frictional effects. During the sensitivity analysis, the friction factor was varied from 0.02 to 0.24. As the friction factor is increased, the forming height of the narrow edge is decreased, and the forming height of the wide edge is increased. When the friction factor becomes 0.2, the earing problem does not occur The experimental results show a good agreement with analytical results.

• 한국시뮬레이션학회논문지
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• 제26권4호
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• pp.11-21
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• 2017

본 논문에서는 선행연구에서 신뢰성을 확보한 지능형 브레이커의 해석모델을 바탕으로 지능형 브레이커의 타격성능 개선을 위한 설계변수 민감도 분석 및 다목적함수 최적화를 다룬다. 본 연구에서는 타격출력만을 향상시키는 기존의 연구를 보완하여 타격출력과 안정성 모두를 개선시키는 것을 목표로 한다. 연구를 진행하는 순서는 다음과 같다. 먼저 정확한 민감도 분석 및 최적화를 진행하기 위하여 해석 시나리오를 설정한다. 그 후 지능형 브레이커의 설계변수 민감도를 분석하고, 상위 민감도를 가지는 변수를 추출한다. 마지막으로 추출한 변수를 사용하여 다목적함수 최적화를 진행하고, 초기 성능과 최적화된 성능의 비교를 통해 기존 지능형브레이커에서 타격성능이 얼마나 향상되었는지 파악한다. 이러한 연구를 통해 국내 기술력으로 기존 해외 선진사의 제품보다 타격성능이 향상된 제품을 개발할 수 있는 가능성을 확보할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2319-2324
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• 2011

Molecular structures and chemical properties of 1-aminoimidazole derivatives have been investigated at high levels of density functional theories. Heat of formation, density, explosive performances and impact sensitivities have been estimated at the global minimum of potential energy surface. As more nitro groups are introduced, the explosive performances of 1-aminoimidazole derivatives are enhanced, while the impact sensitivity becomes more sensitive. A two-dimensional plot between explosive performance and impact sensitivity has been utilized to comprehend the technical status of new explosive candidates. Based on locations in the two-dimensional plot, 1-aminodinitroimidzole isomers appears to have a potential to be good candidates for insensitive explosives, and 1-aminotrinitroimidazole may become a powerful explosive molecule whose behavior is quite close to HMX.

• 환경영향평가
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• 제6권2호
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• pp.113-121
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• 1997

LHR(Landfill Hazard Ranking Model) was developed for assessing the relative hazard of landfills by using the method of value-structured approach. LHR consists of combining a multiattribute decision-making method with a qualitative risk assessment approach. A pairwise comparision method was applied to determine weights of landfill factors related. To prove the validity of weights allocation of landfill hazard evaluation factors, sensitivity analysis was applied. Firstly, the impact on landfill hazard score according to variations of weights of landfill hazard factors was analyzed. Secondly, the impact on landfill hazard score according to conditions change of landfill hazard factors was analyzed. As a result of sensitivity analysis, LHR composite scores are largely influenced by some factors following sequential order such as waste volume, proximity to sensitive environments, containment facilities, distance from drinking water supplies, and waste toxicity. The relative order of landfill hazard evaluated by LHR is not influenced by the weights change of individual factors. Therefore, LHR seems to be a credible model to determine priorities of landfill remediation based on the vulnerability of water resources.