http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
윤성민,김춘철,서원일,황선영,이성훈,한경호,이우범 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-
To detemine seasonal fluctuations in abundance and speices composition, polychaete samples were collected by Van Veen grab form March to November 2003 in Kangjin Bay. A total of 25,119.3 ind./㎡ polycaete were sampled and identified into 48 species. 25 families and 10 orders. Of the 10 orders. Phllodocida, Spionida, Eunicida and Sabellida accounted for approximately 79.9% of the polychaete fauna in this area. Phyllodocida, Nereidae, Nephtyidae ans Spionidae were dominant representing every moment 4 species. Of 48 species identified Neanthes japonica, Prionospio pinnate, Cirratulus cirratus and Palola siciliensis for 54.0% individuals collected. Season succession of dominant species was evident in study area: Neanthes japonica, Prionospio pinnata. Cirratulus cirratus. Nephtys oligobranchia in March, Neanthes japonica, Lumbrineris japonica. Cirratulus cirratus, Prionospio pinnata in May, Ncanthes japonica, Cirratulus cirratus, Lumbrineris nippnica. Lumbrineris japonica in August and Neanthes japonica, Prionospio pinnata, Laonice cirrata, Palola siciliensis in November, respectively. The diversity index was the highest value in March(H'=3.0059) and the lowest value in May(H'=2.7305). The eveness index was the highest in August(J=0.9184) and lowest in May(J=0.8524). The dominance index was the highest in May(D=0.3843) and the lowest in March(D=0.2275).
Chel-hun Woo,Jae-soo Kim,이경환 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.3
Unlike the steady closed- type supersonic cavity flow, open- type cavity flow is divided into internal and external flows by turbulent shear layer. The cavity flow may cause resonance phenomena due to pressure oscillation, depending on the cavity geometry and the flow conditions. These phenomena may induce noise generation, structural damage, and aerodynamic instability. In this research, the flow characteristics of three-dimensional supersonic cavity flow of Mach number 1.5 were analyzed with the variations of aspect ratio and width ratio. Three-dimensional unsteady compressible Reynolds-averaged Navier-Stokes (RANS) equations were used with a turbulence model. For numerical calculations, the 4th-order Runge-Kutta method and the FVS method with van Leer's flux limiter were applied. The numerical calculations were performed by using a parallel processing program with 16 CPUs. The sound pressure level (SPL) spectra of pressure variations were analyzed at the point of cavity leading edge. The correlation of pressure distribution (CPD) was also analyzed for the propagation of dominant oscillation pressure waves with respect to the reference point of the cavity leading edge. The dominant oscillation frequency was compared with the oscillation modes of Rossiter's formula. Oscillation Mode 2 appeared as a dominant oscillation frequency regardless of the aspect ratio of cavity in the two-dimensional flow. Oscillation Modes1 and 2 appeared in three-dimensional cavities of small aspect ratios. However, as the aspect or the width ratio increases, only the mode 2 or 3 frequency appeared as a dominant oscillation frequency.
Analysis of Two Dimensional and Three Dimensional Supersonic Turbulence Flow around Tandem Cavities
Chel Hun Woo,Jae Soo Kim,Kyung Hwan Lee 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.8
The supersonic flows around tandem cavities were investigated by two-dimensional and three-dimensional numerical simulations using the Reynolds-Averaged Navier-Stokes (RANS) equation with the k-ω turbulence model. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves, and the acoustic effect transmitted from wake flow to upstream. The upwind TVD scheme based on the flux vector split with van Leer's limiter was used as the numerical method. Numerical calculations were performed by the parallel processing with time discretizations carried out by the 4th-order Runge-Kutta method. The aspect ratios of cavities are 3 for the first cavity and 1 for the second cavity. The ratio of cavity interval to depth is 1. The ratio of cavity width to depth is 1 in the case of three dimensional flow. The Mach number and the Reynolds number were 1.5 and 4.5 × 10?, respectively. The characteristics of the dominant frequency between two-dimensional and three-dimensional flows were compared, and the characteristics of the second cavity flow due to the first cavity flow was analyzed. Both two dimensional and three dimensional flow oscillations were in the 'shear layer mode', which is based on the feedback mechanism of Rossiter's formula. However, three dimensional flow was much less turbulent than two dimensional flow, depending on whether it could inflow and outflow laterally. The dominant frequencies of the two dimensional flow and three dimensional flows coincided with Rossiter's 2nd mode frequency. The another dominant frequency of the three dimensional flow corresponded to Rossiter's 1st mode frequency.
Analysis of Two Dimensional and Three Dimensional Supersonic Turbulence Flow around Tandem Cavities
Woo Chel-Hun,Kim Jae-Soo,Lee Kyung-Hwan The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.8
The supersonic flows around tandem cavities were investigated by two-dimensional and three-dimensional numerical simulations using the Reynolds-Averaged Navier-Stokes (RANS) equation with the k- ω turbulence model. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves, and the acoustic effect transmitted from wake flow to upstream. The upwind TVD scheme based on the flux vector split with van Leer's limiter was used as the numerical method. Numerical calculations were performed by the parallel processing with time discretizations carried out by the 4th-order Runge- Kutta method. The aspect ratios of cavities are 3 for the first cavity and 1 for the second cavity. The ratio of cavity interval to depth is 1. The ratio of cavity width to depth is 1 in the case of three dimensional flow. The Mach number and the Reynolds number were 1.5 and $4.5{\times}10^5$, respectively. The characteristics of the dominant frequency between two- dimensional and three-dimensional flows were compared, and the characteristics of the second cavity flow due to the first cavity flow was analyzed. Both two dimensional and three dimensional flow oscillations were in the 'shear layer mode', which is based on the feedback mechanism of Rossiter's formula. However, three dimensional flow was much less turbulent than two dimensional flow, depending on whether it could inflow and outflow laterally. The dominant frequencies of the two dimensional flow and three dimensional flows coincided with Rossiter's 2nd mode frequency. The another dominant frequency of the three dimensional flow corresponded to Rossiter's 1st mode frequency.
만삭 전 조기양막파수에서 분만 잠복기에 따른 주산기 예후에 관한 연구
김우선 ( Woo Sun Kim ),최철훈 ( Chel Hun Choi ),이수호 ( Su Ho Lee ),최석주 ( Suk Joo Choi ),김지운 ( Ji Un Kim ),이은실 ( Eun Sil Lee ),손영수 ( Young Soo Son ),김종화 ( Jong Hwa Kim ),노정래 ( Cheong Rae Roh ) 대한주산의학회 2004 Perinatology Vol.15 No.4
목적 : 조기양막파수 산모에서 양막파수에서 분만까지의 기간(잠복기)이 주산기 예후에 미치는 영향을 조사하기 위하여 본 연구를 시행하게 되었다. 방법 : 1996년 1월부터 2003년 10월까지 조기양막파수로 34주 이전에 분만한 223명을 대상으로 분만 잠복기에 따라 6군(I군 : 6시간 이하, II군 : 6시간~2일, III군 : 2~4일, IV군 : 4~7일, V군 : 7~12일, VI군 : 12일 이상)으로 구분한 후 각 군의 임상 양상과 주산기 예후를 관찰하였다. 결과 : 전체 산모의 입원 시 평균 임신 주수는 29.6±2.6주이었고 양막파수 당시 평균 양수지수는 7.3±5.0 이었다. 평균 분만 주수는 30.6±2.4주였고, II군과 III군에서 유의하게 높았다(p=0.0017). 중앙 잠복기는 전체 산모에서 102시간(4일 6시간)이었고 67%의 산모가 1주 이내에 분만하였다. 분만 잠복기는 양막파수 당시 주수가 30주 이하일 때(175시간 vs. 76시간, p=0.001) 연장되었고, 자궁 수축 억제제를 사용했을 때(131시간 vs. 33시간, p=0.001) 분만 잠복기는 유의하게 증가하였다. 양막파수 당시 양수지수는 잠복기에 영향을 미치지 않았다(p>0.05). 분만 주수를 보정하였을 경우 V군에서 조직학적 융모양막염이 유의하게 많이 발생하였고(60%), 분만 잠복기가 증가함에 따라 신생아 중환자실 재원 기간이 증가하였다. 신생아 호흡곤란 증후군은 II군과 IV군에서 I군에 비해 유의하게 적게 발생하였다(12%, 16% vs. 69%). 신생아 사망률은 I군이 18%로 가장 높았고, 분만 주수를 보정하였을 때에도 같은 결과를 보였으나 I군을 제외한 다른 군들 간에는 유의한 차이가 없었다. 그 외 다른 신생아 합병증은 각 군간 유의한 차이가 없었다. 결론 : 만삭 전 조기양막파수에서 즉각적인 분만보다는 적극적인 관찰요법을 통하여 분만 잠복기를 연장시키는 것이 신생아 사망이나 신생아 호흡곤란 증후군의 빈도를 줄이는데 도움이 되나 7일 이상 지연시키는 것은 주산기 예후의 향상과는 관계없이 감염성 합병증을 증가시키는 것으로 보인다. Objective : To evaluate the clinical characteristics and perinatal outcomes in relation to the latency period after preterm premature rupture of membrane (PPROM). Methods : We analyzed retrospectively the 223 pregnant women with PPROM who delivered before 34 weeks of gestation in Samsung Seoul Hospital from January 1996 to October 2003. The study population was divided into six groups according to the larency from membrane rupture and delivery (group I : shorter than 6 hours, group II : 6~48 hours, group III: 2~4 days, group IV : 4~7 days, group V : 7~12 days, group VI : beyond 12 days). Results : The mean gestational age (GA) at rupture was 29.6±2.6 weeks and the mean GA at delivery was 30.6±2.4 weeks. The median latency was 102 hours and 67% of patients delivered within 7 days. The latency was prolonged with GA at rupture before 30 weeks and used of tocolytics. After adjustment of GA at delivery, pathologic chorioamnionitis occurred more frequently in group V than group I. Respiratory distress syndrome occurred less frequently in group II and group IV than group I. Neonatal mortality rate was highest in group I, but the other neonatal morbidities were not significant differences. Conclusion : In PPROM with delivery before 34 weeks, prolongation of the latency longer than 6 hours seems to be beneficial for reducing neonatal RDS and mortality, but infectious morbidity seems to increase when the latency was prolonged longer than 7 days without any benefits for perinatal outcomes.