• 제목/요약/키워드: Water mass changes

검색결과 248건 처리시간 0.03초

Analytical Research of Topside Installation in Mating phase with Crane Vessel

  • Lee, Jong-Hyun
    • 한국해양공학회지
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    • 제25권4호
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    • pp.1-6
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    • 2011
  • The installation of a topside structure can be categorized into the following stages: start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the module onto the floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with a significant wave height (1.52m). The effects of the hydrodynamic interactions between the heavy lifting vessel and the spar hull during the lowering and mating stages are considered. The internal forces caused by the load transfer and ballasting are derived for the mating phases. The results of the internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of the pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the mating phases, the internal force induced pitch motion is too small to have this influence. However, the effect of the internal force on the wave-induced heave responses in the mating phases is noticeable in the irregular sea condition because transfer mass-induced draught changes for the floating structure are observed to have higher amplitudes than the external force induced responses. The impacts of the module on the spar hull in the mating phase are investigated.

Dynamic Analysis of Topside Module in Lifting Installation Phase

  • Lee, Jong-Hyun
    • 한국해양공학회지
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    • 제25권4호
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    • pp.7-11
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    • 2011
  • The installation phase for a topside module suggested can be divided into 9 stages, which include start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the topside module from a transport barge to a crane vessel takes place in the first three stages, from start to lifting, while the transfer of the module onto a floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with significant wave height (1.52m), with suggested force equilibrium diagrams. The effects of the hydrodynamic interactions between the crane vessel and barge during the lifting stage have been considered. The internal forces caused by the load transfer and ballasting are derived for the lifting phases. The results of these internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the lifting phases, the internal force induced pitch motion is too small to show its influence. However, the effect of the internal force on the wave-induced heave responses in the lifting phases is noticeable in the irregular sea condition because the transfer mass-induced draught changes in the floating structure are observed to have higher amplitudes than the external force induced responses.

여름철 동중국해 및 남중국해 표층수의 Ra 동위원소를 이용한 수계분석 (Hydrographic Analysis of Surface Water Using Radium Isotopes Signature in the East and South China Sea in Summer)

  • 양한섭;이동섭
    • 한국해양학회지:바다
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    • 제4권4호
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    • pp.305-311
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    • 1999
  • 라디움(Ra) 동위원소 분포특성을 이용하여 동중국해와 남중국해 여름철 표층수의 해수의 조성을 밝히고자 하였다. 염분과 라디움 동위원소 방사능비($^{228}Ra/^{226}Ra$)의 분포는 동중국해와 남중국해에서 각기 쿠로시오 표층수와 장강 희석수, 쿠로시오 표층수와 연안 희석수의 두 단성분 해수의 단순혼합으로 설명하기에 적절하게 점진적으로 변화하는 분포양상을 나타냈다. 동중국해의 경우에 두 단성분 해수의 혼합은 Ra 동위원소비와 염분의 두 추적자로 각각 정량화가 가능하였는데, 결과를 비교해 보면 쿠로시오에 가까운 정점에서는 매우 비슷한 결과를 보였으나 대마난류가 분지된 이후부터는 차이가 커지기 시작하였다. 이러한 차이를 보이게 하는 가능한 요인으로 중층수와의 혼합이 지목되었다. 이 경우 염분과 Ra 동위원소비는 서로 반대방향으로 교란될 것으로 예상된다. 즉 염분은 저염수의 기여도를 과소평가하는 방향으로 반대로 Ra 동위원소비는 과대평가하게 되므로 두 결과값의 중간값이 실제에 가까울 것으로 판단되었다.

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과체중 및 비만 환자의 체중감량을 위한 식사량 조절 및 복합 한약 단기 치료(5일 레스큐 프로그램)의 효과와 안전성: 진료기반 연구 (Effect and Safety of Calorie Restriction and Complex Herbal Medicine Short-term Treatment ('Oil-rescue' Program) for Weight Reduction of Obesity or Overweight Patients: A Practice Based Research)

  • 권병조;이은지;장정현;송창은;이혜련;김정은;윤영희;최예용;윤상훈;임정태
    • 한방비만학회지
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    • 제20권2호
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    • pp.122-130
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    • 2020
  • Objectives: This study is a practice based research conducted to investigate the effectiveness and safety of a 5-day short-term diet program ('Oil-rescue' program) designed to reduce the adverse events and initial dropout rate in obesity treatment. Methods: We retrospectively analyzed 4 Korean medicine clinic patient data who completed 'Oil-rescue' program which is consisting of Gambi-hwan, Bium-hwan, Butgiban-hwan and Jayoon Kyungokgo. The weight change before and after participating 'Oil-rescue' program was primary outcome of our study. Changes in body mass index, body fat mass, skeletal muscle mass, body water content, lean body mass, protein, and minerals were also measured. Results: A total of 35 patients who satisfied the eligible criteria were finally included. The body weight decreased from 69.45±11.86 kg to 67.43±11.58 kg, a total of 2.02±1.03 kg (P<0.001). Body fat mass decreased from 25.77±7.45 kg to 24.98±7.26 kg, a total of 0.78±1.21 kg (P<0.001). Body mass index decreased from 26.39±3.64 kg/㎡ to 25.64±3.49 kg/㎡, a total of 0.75±0.41 kg/㎡. (P<0.001). A total of 15 patients had side effects such as diarrhea, abdominal pain, and insomnia, but all were mild. 16 out of 35 people switched to long-term obesity treatment programs. Conclusions: Through this retrospective practice based research, it was found that the 'Oil-rescue' program effectively reduced body weight, body fat, and body mass index, and the other obesity related parameters. It was a relatively safe and effective short-term obesity treatment program.

A Study on Gas-Liquid Contact in a Perforated Plate-Type $SO_2$ Absorber at Flooding Conditions

  • Han, Seung-Ho;Soowoo Kwon;Sangwon Jung;Jaehyuk Junk;Yang, Chang-Ryung;Carl Weilert
    • Journal of Korean Society for Atmospheric Environment
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    • 제15권E호
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    • pp.17-28
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    • 1999
  • Gas-liquid contact tests above a perforated-plate were conducted with air and water at flooding gas-flow conditions in order to study two-phase flow characteristics in a limestone-gypsum SO2 absorber. Gas layers were in the form of air pockets and confined to the limited areas around each duct pipe, while the remaining tary area were in the wet condition. The liquid above the tray was always in the flooded and even fluidized conditions at gas flows over the range studied, although vigorous bubbly or churn-turbulent two-phase regime was only observed in the immediate vicinity of the gas hole exit at low gas loads. The froth zone was extremely active to provide intimate contact between gas and liquid so that the necessary mass transfer operation can take place, which is the primary purpose of high-performance SO2 absorbers. Howefer, the absorber $\Delta$P was 250mmH2O for the initial water level at 150mm, which is an important issue to be resolved for economical operation of the SO2 absorber. It was seen in the liquid level-and gas flow-transient tests that changes in the absorber liquid inventory were much more pronounced for intimate gas-liquid contact than changes in the gas flow. Based on the 4- and 8-duct pipe test results, grouping the duct pipes near the center of the test tray seemed to promote better recirulation of liquid from gas-liquid contact zone back to the reaction tank so that the absorbed SO2 can be neutralized.

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감수(甘遂), 과체(瓜蔕)의 임상활용에 관한 후향적 차트리뷰 (A Retrospective Chart Review of the Clinical Use of Euphorbia kansui Radix, Melonis Calyx)

  • 김동현;노지원;정수민;안세영;안영민;이병철;유정화
    • 대한한방내과학회지
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    • 제40권6호
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    • pp.1015-1025
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    • 2019
  • Objectives: There have been many studies reporting the clinical value of Euphorbia kansui Radix or Melonis Calyx, but few systematic studies of the changes that may occur after taking such herbal medication. This study aimed to investigate the characteristics of the patient group, possible changes in blood test and InBody test results, and to discover the current state and future direction of clinical use of Euphorbia kansui Radix or Melonis Calyx. Methods: This study investigated patients who were hospitalized at Kyung-Hee University Korean Medicine Hospital for at least two days from 1 March 2016 to 1 March 2019, specifically evaluating patients aged 19 and over who underwent blood tests, including an electrolyte test and an InBody test before and after taking Euphorbia kansui Radix or Melonis Calyx. Results: Among a total of 134 patients, 72 patients (53.7%) were treated with Euphorbia kansui Radix and 62 patients (46.3%) were treated with Melonis Calyx, in the context of previously diagnosed abnormal weight gain. Laboratory findings were that Na and K levels were significantly reduced in both groups. In an InBody test, body mass index (BMI), intracellular water, extracellular water, protein, mineral, and skeletal muscle were significantly reduced in both groups. Conclusions: From these results, we suggest that, although Euphorbia kansui Radix and Melonis Calyx may not induce serious adverse effects, attention should be paid to the electrolyte level with the use of these treatments. In terms of syndrome differentiation, more clinical uses will be available in the future.

자작나무 콘테이너묘(苗)의 경화단계(硬化段階) 생장(生長)에 미치는 UV-B 와 수분(水分)스트레스의 효과(效果) (Effects of UV-B Radiation and Water Stress on Hardening Phase Growth of Container-Grown Betula platyphylla Seedlings)

  • 김종진;홍성각
    • 한국산림과학회지
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    • 제87권4호
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    • pp.601-610
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    • 1998
  • 본 연구는 시설에서 자란 콘테이너 묘목(苗木)의 경화과정(硬化過程)에 UV-B의 이용 가능성을 탐색하고자 생장상(生長箱)에서 4개월간 생육(生育)시킨 자작나무 묘목을 대상으로 UV-$B_{BE}$ $3.2KJ\;m^{-2}\;day^{-1}$$5.2KJ\;m^{-2}\;day^{-1}$ 수준의 UV-B 처리와 수분(水分)스트레스 처리(處理)를 4주간 실시하여 경화처리 전(前), 후(後)의 생장(生長) 및 생리적(生理的) 특성을 비교 분석하였다. UV-B 또는 수분스트레스 처리는 수고생장(樹高生長), 잎의 건물량축적(建物量蓄積)을 감소시켰다. UV-B 처리는 근원경생장(根元徑生長)을 감소시켰으나 수분스트레스 처리는 근원경생장을 증진시켰다. UV-B 처리 또는 수분스트레스 처리에 의한 잎의 건물량감소는 묘목의 T/R율을 감소시켰다. T/R율의 감소효과는 수분스트레스 처리에서 가장 크게 나타났다. 엽록소(葉緣素) 지수(指數)는 UV-B 5.2에서 가장 낮았으며 UV-B 3.2와 수분스트레스 처리에서는 비슷한 수준이었다. UV-B 또는 수분스트레스 처리는 콘테이너 묘목의 함수율(含水率)과 수분포텐셜을 낮추었으며 삼투압(滲透壓)을 높혔다. 경화처리에 의한 잎과 줄기의 함수율 감소는 UV-B 처리에 의해서는 빠르게 일어났으나 수분스트레스 처리에 의해서는 보다 서서히 일어났다. 이상의 결과를 보면, 자작나무 콘테이너 묘목의 경화단계에 처리된 UV-B에 의한 생장반응(生長反應) 및 수분생리(水分生理) 변화는 수분스트레스 처리에서의 효과와 유사한 면이 관찰되었다.

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자료동화 기법에 따른 황·동중국해 지역 해양순환모델 결과 비교 (Comparison of Data Assimilation Methods in a Regional Ocean Circulation Model for the Yellow and East China Seas)

  • 이준호;문재홍;최영진
    • Ocean and Polar Research
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    • 제42권3호
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    • pp.179-194
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    • 2020
  • The present study aims to evaluate the effects of satellite-based SST (OSTIA) assimilation on a regional ocean circulation model for the Yellow and East China Seas (YECS), using three different assimilation methods: the Ensemble Optimal Interpolation (EnOI), Ensemble Kalman Filter (EnKF), and 4-Dimensional Variational (4DVAR) techniques, which are widely used in the ocean modeling communities. The model experiments show that an improved initial condition by assimilating the SST affects the seasonal water temperature and water mass distributions of the YECS. In particular, the SST data assimilation influences the temperature structures horizontally and vertically in winter, thereby improving the behavior of the YS warm current water. This is due to the fact that during wintertime the water column is well mixed, which is directly updated by the SST assimilation. The model comparisons indicate that the SST assimilation can improve the model performance in resolving the subsurface structures in wintertime, but has a relatively small impact in summertime due to the strong stratification. The differences among the different assimilation experiments are obvious when the SST was sharply changed due to a typhoon passage. Overall, the EnKF and 4DVAR show better agreement with the observations than the EnOI. The relatively low performance of EnOI under storm conditions may be related with a limitation of EnOI method whereby an analysis is obtained from a number of climatological fields, and thus the typhoon-induced SST changes in short-time scales may not be adequately reflected in the data assimilation.

낙동강 하구 해양환경 및 기상 요인이 김P(orphyra yezoensis) 생산량 변화에 미치는 영향 (Effects of Meteorological and Oceanographic Properties on Variability of Laver Production at Nakdong River Estuary, South Coast of Korea)

  • 권정노;심정희;이상용;조진대
    • 한국수산과학회지
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    • 제46권6호
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    • pp.868-877
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    • 2013
  • To understand the effects of marine environmental and meteorological parameters on laver Porphyra yezoensis production at Nakdong River Estuary, we analyzed marine environmental (water temperature, salinity, nutrients, etc.) and meteorological properties (air temperature, wind speed, precipitation, sunshine hours) with yearly and monthly variations in laver production over 10 years (2003-2013). Air and water temperature, wind speed, sunshine hours and precipitation were major factors affecting yearly variability in laver production at the Nakdong River Estuary. Lower air and water temperatures together with higher levels of nutrients and sunshine and stronger wind speeds resulted in higher laver harvests. Salinity and nitrogen did not show clear correlations with laver production, mainly due to the plentiful supply of nitrogen from river discharge and the low frequency of environmental measurements, which resulted in low statistical confidence. However, environmental factors affecting monthly laver production were related to the life cycle (culturing stage) of Porphyra yezoensis and were somewhat different from factors affecting annual laver production. In November, a young laver needs lower water temperatures for rapid growth, while a mature laver needs much stronger winds and more sunshine, as well as lower temperatures for massive production and effective photosynthesis, mostly in December and January. However, in spring (March), more stable environments with fewer fluctuations in air temperature are needed to sustain the production of newly deployed culture-nets ($2^{nd}$ time culture). These results indicate that rapid changes in weather and marine environments caused by global climate change will negatively affect laver production and, thus, to sustain the yield of and predict future variability in laver production at the Nakdong River estuary, environmental variation around laver culturing farms needs to be monitored with high resolution in space and time.

저서성 유공충 Oridorsalis umbonatus의 산출 상태에 기록된 후기 올리고세 북대서양 심층수의 강화 (The strengthening of North Atlantic Deep Water during the late Oligocene based on the benthic foraminiferal species Oridorsalis umbonatus)

  • 이호준;조경남;임재수
    • 지질학회지
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    • 제54권5호
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    • pp.489-499
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    • 2018
  • 올리고세의 시작과 함께 발생된 남극 대륙빙하의 형성, 해류 시스템 변화, 고생물 멸종 등 일련의 사건들은 현재까지 지질학자들로부터 매우 주요한 관심을 받아왔다. 하지만 이에 반해 에오세-올리고세 전이기(Eocene-Oligocene transition; EOT) 이후 올리고세 대부분의 기간 동안 발생된 고기후 고해양학적 변화에 대해서는 아직까지도 연구가 미흡한 상태이다. 특히, 후기 올리고세 온난화(late Oligocene warming; LOW)는 올리고세 동안 발생된 고기후 고해양학적 변화에 있어 가장 큰 규모의 사건 중 하나로 인식되고 있지만, 이 시기에 발생된 구체적인 변화 요소에 대한 이해는 매우 부족한 실정이다. 이번 연구는 IODP Expedition 342를 통해 북대서양 J-Anomaly Ridge에서 획득한 시추코어 퇴적물을 이용해 후기 올리고세 온난화 동안 어떤 고해양학적 변화가 발생되었는지 알아보기 위해 수행되었다. 연구지역은 북대서양 심층수(North Atlantic deep water; NADW)에 의해 직접적으로 영향을 받고 있기 때문에 과거 NADW의 변화를 연구하기에 적합한 곳으로 잘 알려져 있다. 고지자기 층서모델을 이용해 산출된 퇴적물의 연대는 약 26.0~26.5 Ma로 LOW의 초반부에 해당되는 시기이다. 이 퇴적물 시료로부터 산출되는 저서성 유공충의 한 종인 Oridorsalis umbonatus의 각질 크기 자료와 입도분석 결과는 서로 매우 유사한 변화경향성을 보여주는 것으로 나타났다. 이러한 연구 결과를 바탕으로 해당 시 추코어 퇴적물은 총 3개의 구간(Unit 1, 2, 3)으로 나누어지며, 그 중 Unit 2는 가장 큰 각질의 O. umbonatus가 산출되는 동시에 퇴적물 입자 크기도 가장 큰 것으로 나타났다. 또한 O.umbonatus의 개체수 역시 Unit 2에서 가장 높은 것으로 나타났다. O. umbonatus의 개체수, 각질 크기 변화, 입도 변화는 산소농도와 심층수 순환 강도의 프록시로 활용될 수 있기 때문에 이번 연구에서는 Unit 2가 퇴적된 시기 동안 NADW의 세기가 가장 강했던 것으로 해석하였다. 이와 같이 LOW 초기 동안 발생된 NADW의 강화는 기존 북대서양 저위도 지역의 Cibicidoides spp. 산소 및 탄소안정동위원소 자료를 통해서도 확인할 수 있다. 이번 연구의 결과는 LOW의 시작 원인이 NADW의 강화와 같은 고해양학적 변화와 연관되어 있다는 기존 연구결과를 지지하는 새로운 증거를 제시해준다.