• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.94-99
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• 2007

Many cases of acute cardiac shock and cardiac arrest in emergency room and ICU have been increasing. In this case, ECMO with centrifugal pump has been used generally. However, due to the heavy weight and big size, the system is not adequate for emergency cases. And other defects of this system are that membrane oxygenator's pressure is high and blood are exposed to the air. There was some tries of ECMO using pulsatile pump, but it was found that the weak point of these system is high peak pressure and hemolysis. The mechanism of twin pulsatile pump is that Membrane oxygenator Outlet Pump(MOP) make negative pressure when Membrane oxygenator Inlet Pump(MIP) provides high positive pressure, and the negative pressure will decrease positive pressure of Membrane Oxygenator. Our group analyzed this advantage through In-Vitro and 12 Cases In-Vivo test.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.97-97
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• 2010

많은 플라즈마 공정 중에 건식 식각은 복잡하고 표면반응이 잘 알려지지 않은 등의 이유로 가장 어려운 분야 중의 하나이다. 이러한 이유로 식각 장치 디자인뿐만 아니라 플라즈마를 이용한 건식 식각의 공정 조건은 수많은 시행착오를 통해 시도되어 왔다. 이런 문제들을 극복하기 위해 많은 연구자들에 의해서 다양한 방법과 tool을 이용해 모델링이 시도되고 있다. 본 연구에서는 $CF_4$ 가스를 이용한 유도결합 플라즈마에 의해 Si와 $SiO_2$를 식각하는 것을 상용 프로그램인 전산모사 유체역학 시뮬레이터인 CFD-ACE+를 이용하여 모델링했다. 150 mm 직경의 웨이퍼에 대한 모델은 식각 속도 실험결과와 비교 하였다. Ar의 경우 20 mTorr에서 13.56 MHz, 500 W인가 시 2.0 eV의 전자온도와 $7.3{\times}10^{11}\;cm^{-3}$의 전자밀도가 계산결과와 상당히 일치하게 측정되었고, $CF_4$를 이용한 $SiO_2$ 식각에서도 식각 속도가 평균 190 nm/min로 일치했고 식각 균일도는 3% 였다. 450 mm 웨이퍼 공정용 장치의 모델 계산 결과에서는 안테나와 기판의 거리, 챔버의 단면적, 기판 지지대와 배기구와의 높이 등 기하학적인 구조와 각 안테나 턴의 위치 및 전류비가 플라즈마 균일도에 많은 영향을 주었으며, 안쪽부터 4 turn이 있는 경우 2번째, 4번째 turn에만 1:4의 전류비를 인가했을 때, 수십%의 전자밀도의 불균일도를 4.7%까지 낮출 수 있었다. 또한, Si 식각에서는 식각 속도의 분포가 F radical의 분포와 같은 경향을 보임을 확인했고, $SiO_2$ 식각에서는 전자 밀도의 분포와 일치함을 확인함으로써 균일한 식각을 위해서 두 물질의 식각 공정에서는 다른 접근의 시도가 필요함을 확인했다. 플라즈마의 준중성 조건을 이용해서 Poisson 방정식을 풀지 않고 sheath를 해석적 모델로 처리하는 방법과, Poisson 식으로 정전기장을 푸는 방법을 통해서 입사 이온의 에너지 분포를 비교하였다. 에너지 범위는 80~120 eV로 같지만, 실험에서는 IED가 낮은 에너지 쪽이 더 높게 측정됐고, 계산 결과에서는 높은 에너지 쪽이 높았다.

• The Journal of the Korea Contents Association
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• v.13 no.7
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• pp.432-439
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• 2013

In this study, we evaluate the volatility of housing prices by using literature review and empirical analysis and furthermore we suggest how to improve. In order to diagnose housing market, the KB Bank's House Price Index, Real estate 114;s materials were compared. In addition, to examine the volatility, GARCH (Generalized Autoregressive Conditional Heteroskedasticity) and EGARCH (Exponential GARCH) model are used. By analysis of this research, we found the volatility of housing price also was reduced in the medium and the large houses since 1998, while the volatility of small housing price relatively was large. We proved that the price change rate of small housing was higher than the medium's. On the order hand, the supply of small apartments fell down sharply. The short-term oriented policy should be avoided, and the efficiency and credibility of policy should be increased. Furthermore, the long-term policy system should be established. and rental market's improvement is necessary for stabilization of housing market.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.201-207
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• 2021

This study investigated the effects of self-esteem on the depression of baby boomer and eco-boomer generation (the children of baby boomers) living alone. It was identified from the point of view of comparison between the two groups. Using the 15th data of the 2020 Korea Welfare Panel, an independent sample t-test and hierarchical regression analysis were conducted with the data of baby boomers who live alone (born in 1955-1963) and eco-boomers who live alone (born in 1979-1992). The results of this study show that baby boomers who live alone had lower levels of education, income, and health condition than the eco-boomers who live alone, and had higher level of depression, but relatively lower level of self-esteem. In both groups, self-esteem had an effect on depression, but it was confirmed that the influence was greater in the group of baby boomers (Adjusted R2 .259) than in eco-boomers (Adjusted R2 .083). Based on the results of this study, practical and policy alternatives were suggested to prevent the depression among middle-aged, elderly people, and young adults who live alone.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.35-47
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• 2023

Purpose : As the population aging deepens, the number of elderly people with arthritis is also continuously increasing. Accordingly, this study intended to identify the factors influencing the health-related quality of life (HINT-8) of the elderly with arthritis according to household type and provide baseline data for developing a measure to enhance the life quality of the elderly with arthritis. Methods : The factors influencing the health-related quality of life (HINT-8) of the elderly with arthritis were identified based on the raw data from the Korea national health and nutrition examination survey conducted in 2021. Data were analyzed with SPSS Statistics ver 25.0 for windows (IBM Corp), and the significance level (α) was set to .05. Statistical analysis was performed with t-test, ANOVA, multiple regression analysis, and post-hoc analysis with Duncan test. Results : The factors that influenced the health-related quality of life (HINT-8) of single-households were medical aid (β=-.17, p=.045), restriction of activity (β=-.17, p=.023), self-rated health status (β=.29, p<.001), and anxiety scale (β=-.36, p<.001). The factors that influenced the health-related quality of life (HINT-8) of multi-households were an age of 75 or over (β=-.14, p=.011), living in rural (β=-.14, p=.003), the outpatient department treatment experience (β=-.09, p=.047), self-rated health status (β=.26, p<.001), anxiety scale (β=-.29, p<.001), and stress (β=-.22, p<.001). Conclusion : Factors affecting the health-related quality of life (HINT-8) of the elderly with arthritis were found to be different between single-person households and multi-person household. Therefore, it is necessary to prepare measures to improve the quality of life of the elderly with arthritis by considering the factors influencing the health-related quality of life (HINT-8) of the elderly with arthritis according to the household type identified in this study.

• Journal of the Korean Vacuum Society
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• v.7 no.2
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• pp.118-126
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• 1998

A study to improve filling of semiconductor contact holes by enhancement of the directionality of the source beams has been undertaken. The collimation of source beams was improved by the ionized cluster beam deposition technique with modification of the cell geometry. The collimation tested with neutral beam was excellent. But, the Cu flims were grown in a columnar mode due to the lack of surface mobilit of the impinged clusters. A shadow effect also caused cleavage and consequent discontinuity at the steos as films grow. By applying acceleration voltage, the columnar growth in a contact hole of 0.5 $\mu$m diameter and 1 $\mu$m height disappeared and considerable coverage at the side wall of the contacts as well as perfect bottom coverage were observed. These are all due to the assistants of the accelerated ionized clusters with high kinetic energy. Thus we demonstrated that the ICB deposition technique can be used to completely fill sub-half-micron contact holes with high aspect ratio.

• Land and Housing Review
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• v.14 no.2
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• pp.19-34
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• 2023

The proportion of single-person households has been steadily increasing, and the young account for the highest proportion at 35.9% among all single-person households. However, research on young single-person households has been relatively recent. Research on single-person households has mostly focused on all single-person households or elderly single-person households, and comparative research between different age groups is lacking. Therefore, this study categorizes all single-person households into young, middle-aged, and elderly groups to investigate the differences in the factors that affect their residential satisfaction and to analyze how these residential environment factors affect life satisfaction through the mediating effect of residential satisfaction. The 2020 Seoul Survey Urban Policy Index Survey data were analyzed using a structural equation model to investigate the impact of each factor. First, a finding is that various residential environment factors directly affect residential satisfaction and life satisfaction. Next, it was found that residential satisfaction directly affects life satisfaction in the models of young and middle-aged single-person households. Through this, it was confirmed that there are differences in residential environment factors that affect residential satisfaction and that residential satisfaction plays an important mediating role. Finally, it was found that the factors that affect the residential and life satisfaction of young single-person households are more diverse compared to other age groups. This study provides policy implications that age group differences should be considered first in order to improve the residential and life satisfaction of single-person households. In particular, for young single-person households, it is necessary to consider more diverse alternatives to improve their residential and life satisfaction.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.234-234
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• 2012

Saddle field ion source는 구조가 간단하고 영구자석을 사용하지 않아 소형화에 유리하고 구조가 간단한 DC 파워서플라이를 이용하기 때문에 장치 가격이 저렴하여 다양한 분야에서 응용되고 있으며 특히 이온빔 밀링 분야에 많이 사용된다. 초기 saddle field ion source 는 대칭형의 구형이었으나 지속적인 연구 개발로 와이어형, 원판형, 원통형 등 다양한 형태의 saddle field ion source가 개발되었다. 본 연구에서는 비교적 제작이 용이하고, 구조적으로 외부간섭에 대하여 덜 민감한 원통형 saddle field ion source를 제작하였다. 초기 saddle field ion source는 이온원 내부에 saddle field를 형성하기 위하여 대칭 구조를 가지 형태로 제작되었으나, 비대칭 구조에서도 saddle field가 형성될 수 있고 비대칭 구조를 채택할 경우 한쪽으로 더 많은 이온빔을 인출할 수 있기 때문에 실제 응용면에서는 비대칭 구조가 더 유리하다. 따라서 본 연구에서는 원통형 비대칭 saddle field ion source를 제작하였으며, 제작된 이온소스는 높이가 62 mm 지름이 55 mm의 소형 이온소스였다. 제작된 원통형 saddle field ion source는 진공도와 가속전압에 따라 방전 모드 변화하였다. Saddle field ion source는 전극과 extractor의 구조에 따라 조금씩 다르지만 대체로 5x10-5 Torr ~ 5x10-4 Torr 영역에서 안정적으로 작동하였다. 이온소스 내부의 압력이 높을 경우 수십 mA 의 방전 전류가 흐르는 고전류 방전 모드로 작동하였으며 압력이 낮을 경우에는 동일한 전압에서 수 mA 의 방전 전류만 흐르는 저전류 방전 모드로 작동하였다. 압력이 더 높아질 경우 아크 방전이 발생하여 이온소스의 작동이 불안정하여 연속적인 작동이 어려웠다. 고전류 방전 모드에서는 이온빔 전류가 Child-Langmuir 방정식에 따라 Vi3/2에 비례하여 증가하는 경향을 보여주었으며 저전류 방전 모드에서는 Vi에 선형적으로 증가하였다. 가속 전압이 동일한 경우 고전류 방전 모드가 저전류 방전 모드에 비하여 더 많은 이온빔 인출이 가능하지만, 고전류 방전 모드의 경우 이온의 방출 각도가 매우 넓은 반면 저전류 방전 모드에서는 이온빔의 퍼짐이 현저히 줄어듦을 관찰할 수 있었다. 원통형 saddle field ion source는 내부 구조가 간단하기 때문에 내부 전극의 구조 변화에 따라 방전 특성 및 이온빔 인출 특성이 심하게 변동하였다. Saddle field ion source에서는 Anode에 인가되는 방전 전압이 가속 전압과 같은 역할을 하는데 가속 전압은 2~10 kV 사이에서 인가가 가능하였다. 일반적으로 동일한 방전 모드에서 진공도가 높아질수록 방전 전류의 양과 인출되는 이온의 양이 증가하는 것이 관찰되었다. 제작된 이온소스는 최적 조건에서 5 mm 인출구를 통하여 0.7 mA의 이온빔 인출이 가능하였으며, 9 mm 인출구를 사용한 경우 1 mA까지 이온빔 인출이 가능하였다.

• 한국노년학
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• v.40 no.2
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• pp.239-255
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• 2020

The purpose of this study is to examine whether family relationships of elderly single-person households affect community participation and whether these relationships differ by gender. Based on Baltes and Baltes (1990) 's selection, optimization, and compensation theory (SOC) and the argument that family members are a social capital by Prandini (2014), we test whether family relationships can affect community participation in old age. In order to verify this, single-person households were extracted from the 2017 National Survey of Living Conditions and Welfare Needs conducted by the Korea Institute for Health and Social Affairs (Male sample=370, Female sample=1770), multiple regression analysis were conducted with the dependent variables of friends·neighbors and the participation at Kyungrodang·welfare centers for the elderly. The results are as follows. In the case of men, family relations showed no significant effect on their participation in friends·neighbors, or Kyungrodang·welfare centers. However, in the case of women, the frequency of contact with family had a positive effect on the frequency of meeting friends·neighbors. Family contact frequency and child relationship satisfaction had a positive (+) effect on Kyungrodang·welfare center participation, while family meeting frequency had a negative effect on participation in Kyungrodang·welfare centers. For women, although Prandini's (2014) claim that family members are a social capital seems to be supported, it was found that the impact could vary depending on the type of community participation. In addition, practical discussions and suggestions were presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.576-584
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• 2006

The actuating performance test of plate-type piezoelectric composite actuators having different lay-up sequences was experimentally carried out at simply supported and fixed-free boundary conditions. The actuating displacement of manufactured plate-type piezoelectric composite actuator (PCA) was measured using a non-contact laser displacement measurement system. Our results revealed that the actuating displacement with increasing applied electric field at a drive frequency of 1Hz increased non-linearly at the simply supported boundary condition whereas it almost linearly increased at the fixed-free boundary condition. On the other hand, the actuating displacement of piezoelectric composite actuator depended on the applied electric field in a drive frequency range from 1Hz to 10Hz, but its behavior was different in higher drive frequencies beyond 15Hz due to the occurrence of resonance. On the basis of the above experimental results, the bending characteristics of PCAs revealed different behavior depending on applied electric fields, drive frequencies as well as boundary conditions. Therefore, by investigating drive frequencies together with applied electric fields, actuating performance can be easily controlled and PCAs which were fabricated for this study will be sufficiently applied to pumping devices.