• Journal of the korean society of oceanography
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• 제37권3호
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• pp.125-133
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• 2002

Water and salt budgets in the Yellow Sea and Bohai are analyzed based on the historical data and CTD data collected recently using box models. The amounts of volume transport and of water exchange across the boundary between the Yellow and East China Seas are estimated to be 2,330-2,840 $\textrm{km}^3$/yr and 109-133 $\textrm{km}^3$/yr, respectively, from the one-layer box model. Corresponding water residence time is 5-6 years. In the Bohai, water residence time is twice as long as that in the Yellow Sea, suggesting that the Yellow Sea and Bohai cannot be considered as a single system in the view of water and salt budgets. The results indicate that water and salt budgets in the Yellow Sea depend almost only on the water exchange between the Yellow and East China Seas. The computation with the coupled two-layer model shows that water residence time is slightly decreased to 4-5 years for the Yellow Sea. In order to reduce uncertainties for the budgeting results the amount of the discharge from the Changjiang that enters into the Yellow Sea, the vertical advection and vertical mixing fluxes across the layer interface have to be quantified. The decreasing trend of the annual Yellow River outflow is likely to result that water residence time is much longer than the current state, especially for the Bohai. The completion of the Three Gorges dam on the Changjiang may be change the water and salt budgets in the Yellow Sea. It is expected that cutting back the discharge from the Changjiang by 10% through the dam would increase water residence time by about 10%.

• 설비공학논문집
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• 제29권5호
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• pp.220-230
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• 2017

In this study we apply and compare a variety of numerical methods for calculating residence time distribution in decay tanks, a major design component in the for reducing N-16 radioactivity. Our research group has used a streamlined method using user-defined particle numbers. However, this streamlined method has several problems, including low exiting particle ratios, particle diminishing, and unphysical time distribution, among others. We utilize three numerical methods to establish residence time and time distribution (streamlined, discrete phase method [DPM], and user defined scalar [UDS]) and subsequently compare the averaged results of each. The three tests demonstrate the flow features within the decay tanks, which are then numerically simulated to enable comparison. We conclude that although each simulation predicts similar time averages, the UDS methodology provides a smoother time distribution and tracer contour plots at specific times.

• 해양환경안전학회지
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• 제22권1호
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• pp.20-26
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• 2016

해역에서의 체류시간은 제한된 영역을 채우는 수체나 오염물질이 잔류하는 시간을 의미하며, 서로 다른 수체간의 물리적 특성을 비교하는 데 사용되고 있다. 거제만으로 유입되는 육상기원 또는 양식기원 입자물질의 잔류시간을 알아보기 위해 입자추적모델이 포함된 EFDC를 이용하여 입자물질 체류시간을 계산하였다. 계산된 입자물질의 체류시간은 내만에서 약 65일이었는데, 이 결과는 거제만 내측으로 유입되는 입자물질이 외해에 도달하기까지 약 2달 이상의 시간이 소요됨을 의미한다. 이 체류시간은 거제만 전역에 걸쳐 조석의 흐름에 따라 다르게 나타났으며, 해역에 유입된 입자물질의 거동이 해역의 물리적 특성에 의해 결정됨을 의미한다. 입자물질 체류시간의 공간적인 분포특성을 통해 거제 내만의 해수교환이 원활하지 않은 것을 알 수 있으며, 이로 인해 수질오염문제에 취약할 수 있다는 것을 알 수 있다.

• 한국해안·해양공학회논문집
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• 제29권5호
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• pp.247-259
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• 2017

입자추적기법(Lagrangian Particle Tracking; LPT)을 적용한 수치모델을 이용하여 조력발전소 운영에 의한 시화호 외측해역에서의 체류시간 변화를 파악하였다. 수치모델의 실험안은 공간적인 분포 특징을 살펴보기 위하여 시화호 외측 해역을 4개 구역으로 나누어 구역별 평균체류시간을 산정하였다. 구역별 평균체류시간은 운영 전과 운영 중 모두 가장 외해에 위치한 지역(약 3일)에서 내만에 위치한 지역(약 13일)으로 진입할수록 증가하는 특징이 나타났다. 구역별 평균체류시간 변화를 운영 전과 운영 중으로 비교하면 운영 전에 비해 운영 중에 가장 외해에 위치한 지역에서는 증가하고 나머지 구역에서는 감소하였다. 조력발전소 운영에 의한 인위적인 배수는 가장 외해에 위치한 지역에서 와동(vortex) 형성으로 입자 정체를 유발하였고, 나머지 지역에서는 연행작용(entrainment)을 발생시켜 체류시간의 변화에 영향을 주었다. 즉, 배수 시 발생하는 제트류(jet flow)와 와동, 연행작용으로 인한 체류시간 변화는 외해와 내만의 수평적 혼합 증가를 보여준다.

• 가정과삶의질연구
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• 제21권2호
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• pp.175-185
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• 2003

The purpose of this study was to investigate whether there is any difference between the dual residence couples and the single residence couples in terms of the situation of child care, development of their child and mother's parenting guilty or parenting stress. Also, this study aimed to explore the variables which influence parenting guilty and parenting stress of dual residence mothers. The 178 mothers of three to eight tear-old participated the survey. Half of them were dual residence mothers and another half were those of single residence. These two groups were matched in terms of the occupation of the mother and the age of the child. Major finding were as follows. 1) Compared with single residence couples, dual residence couples used multiple methods of child care. And they depended maternal families more than paternal ones as a care-giver. They also payed much more for the child care than single residence couples. 2) Children of the dual residence couples did not differ with those of the single residence couples in terms of cognitive and social development. 3) Dual residence mothers had more parenting guilty than those of single residence while these two groups did not differ in terms of parenting stress. 4) While dual residence mother's parenting guilty was significantly related with the amount of information provided by the paternal families, their parenting stress was significantly related with the frequencies of communicating with the husband, the mother's age, the flexibility of time in the mother's work place, the mother's orientation to the career, and the supports of the husband. In conclusion, dual residence families in Korea were not so negative as expected. Furthermore, this study suggests that the parenting difficulties of the dual residence mothers could be decreased by the change of social and economic situations and the psycho-social support of the husband.

• 한국환경과학회지
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• 제8권2호
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• pp.171-176
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• 1999

To estimate the residence times of aerosols in air, the activities of $^{210}Pb$ and $^{210}Po$ in aerosols were measured at 4 sites in Pusan. All aerosol samples were collected by a high volume air sampler from January to October 1996. The activities $^{210}Pb$ and $^{210}Po$ in Pusan were varied from 11.77 to 67.57 dpm/1000$m^3$ and from 2.63 to 15.91 dpm/1000$m^3$, respectively. The mean activities were 34.62 dpm/1000$m^3$ for $^{210}Pb$ and 8.24 dpm/1000$m^3$ for $^{210}Po$. The highest values of the activities of $^{210}Pb$ and $^{210}Po$ were appeared at P3 site and the lowest values at P4 site. During the sampling period, the trends of the activities of $^{210}Po$ and $^{210}Pb$ were similar to total suspended particulate matter(TSP) concentrations. The mean residence times of atmospheric aerosols calculated from $^{210}Po$/$^{210}Pb$ activity ratio was about 60~80 days in Pusan. The longest residence time of atmospheric aerosols was in January because of the lack of rainout and washout, but the shortest residence time was in August, largely due to scavenging effect by frequent rains. The activities of $^{210}Po$ and $^{210}Pb$ in atmospheric aerosols were different in time and space, which seems that the distribution of $^{210}Po$ and $^{210}Pb$ activities and scavenging processes in air may be controlled by the local and meteorological conditions.

• 대한영양사협회학술지
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• 제18권4호
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• pp.297-307
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• 2012

The purpose of this study was to examine the dietary attitudes and meal management of married immigrant women according to residence period in Korea. The study was conducted by administering a questionnaire survey to 220 married immigrant women in Korea. More than one third of the immigrant women who stayed in Korea less than 3 years tended to eat a limited variety of foods. Irregularity of meal time decreased as residence time period increased (P<0.05). As immigrant women stayed longer in Korea, they became more responsible for the diet of their family (P<0.001) and had more time to share breakfast and dinner with all family members (P<0.05). Nearly half of immigrant women in all residence periods indicated their husband's family as the most influential factor in acquiring Korean foods (P<0.05). Immigrant women became more familiar with Korean cooking and recognition of nutritious foods (P<0.001) the longer they lived in Korea and more enjoyable meal times with family (P<0.05). In summary, as the period of residence in Korea increased, the dietary attitudes of immigrant women became more positive towards Korean food and diet culture. Further, immigrant women became more responsible for guiding children's dietary habits and offering healthy foods to their family as residence period increased. Therefore, the government and social programs should conduct constant and organized lessons on Korean culture and cooking according to residence period for immigrant women to build up stable and positive dietary attitudes.

• 노동경제논집
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• 제24권1호
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• pp.97-124
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• 2001

자녀양육에 수반되는 시간적 금전적 비용부담이 기혼여성의 노동시장 진입과 경력단절에 가장 큰 영향을 미치는 요인으로 지적한 선행 연구들은 이에 대한 정책적 지원을 강조하였다. 사회복지정책이 발달한 국가에서 세대간 동거(co-residence)는 고령층의 의료 및 부양과 관련된 공적 비용을 사적 비용으로 전환하고, 공식적인 부양을 비공식적인 것으로 대체하는 동시에 기혼여성의 노동공급을 증가시킨다는 관점에서 정책 설정에서 주요한 개선방안으로 인식되고 있다. 본 연구는 "한국노동패널" 2차년도(1999) 자료를 이용하여 부모세대와의 동거상태, 부모 및 기혼여성 본인의 건강상태가 기혼여성의 노동공급에 미치는 영향을 살펴본다. Tobit모형의 추정 결과, 동거 여부, 여성노인과의 동거, 노동시장 근로를 하지 않는 여성노인과의 동거는 동거하는 노인의 건강상태에 관계 없이 기혼여성의 노동공급량에 정(+)의 효과를 미치는 것으로 나타났다. 세대간 동거는 세대간 사적 자원이전 (intergenerational private transfer of resources)을 통하여 기혼여성의 노동공급에 긍정적인 영향올 미치며, 이는 세대간 사적 자원이전이 여성노인을 중심으로 시간자원의 이전이라는 형태를 취하고 있음을 의미한다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.212.1-212
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• 2003

• 공업화학
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• 제26권1호
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• pp.67-73
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• 2015

전산유체해석 기법을 이용하여, 테일러 반응기 내 유동특성과 입자의 체류시간에 대하여 연구하였다. 테일러 반응기는 반응기의 작동조건에 따라 내부 유동특성이 달라지므로, 입구주입속도와 반응기 회전속도 변화에 따른 테일러 반응기 내부의 유동특성 변화를 살펴보았다. 또한 테일러 와류(TVF)영역에서 리튬이온전지의 양극물질인 NMC입자의 반응기 내 체류시간을 측정하였다. 입구에서의 복잡한 화학반응은 고려하지 않았고 테일러 유동의 영향만 고찰하였다. 해석결과 반응기의 회전속도가 높고 반응물의 주입속도가 낮을수록 입자의 체류시간이 길어지는 것을 확인하였다.