Effective temperatures,radii, and luminosities of O emission,Be and Ae stars     

Jong-Ok Woo 《Astrophysics and Space Science》1986,119(1):61-63

Our de-reddened fluxes, together with the ultraviolet measurements of Thompsonet al. (1978), have been compared with those of Kurucz's (1979) model atmospheres to derive effective temperatures of some O emission, Be and Ae stars. With the measured monochromatic fluxes we determined their angular diameters and luminosities. It is found that the majority of the stars are cooler than the Zero-Age Main Sequence (ZAMS), suggesting that they are slightly more evolved than ZAMS stars.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. The observations were made at the Observatoire de Haute Provence (France) and La Silla (E.S.O., Chile).  相似文献   

Structure in the solar corona from radio scintillation measurements     

Richard Woo 《Astrophysics and Space Science》1996,243(1):97-104

Since the 1950s, a wide variety of radio observations based on scattering by electron density fluctuations in the solar wind has provided much of our information on density fluctuations and solar wind speed near the source region of the solar wind. This paper reviews recent progress in the understanding of the nature of these density fluctuations and their relationship to features on the Sun. The results include the first measurements of fine-scale structure within coronal streamers and evidence for structure in solar wind speed in the inner corona.  相似文献   

Co-existence of plagioclases of different compositions in some plutonic and metamorphic rocks     

Mitsuo Hunahashi  Cheoul Woo Kim  Yoshihide Ohta  Takamura Tsuchiya 《Lithos》1968,1(4):356-373

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Modeling of coupled tide–wave–surge process in the Yellow Sea     

B. H. Choi  H. M. Eum  S. B. Woo 《Ocean Engineering》2003,30(6):739

A coupled wave–tide–surge model has been developed in this study in order to investigate the effect of the interactions among tides, storm surges, and wind waves. The coupled model is based on the synchronous dynamic coupling of a third-generation wave model, WAM cycle 4, and the two-dimensional tide–surge model. The surface stress, which is generated by interactions between wind and wave, is calculated by using the WAM model directly based on an analytical approximation of the results using the quasi-linear theory of wave generation. The changes in bottom friction are created by the interactions between waves and currents and calculated by using simplified bottom boundary layer model. In consequence, the combined wave–current-induced bottom velocity and effective bottom drag coefficient were increased in the shallow waters during the strong storm conditions.  相似文献   

Glaciomarine sedimentation and palaeo-glacial setting of Maxwell Bay and its tributary embayment, Marian Cove, South Shetland Islands, West Antarctica     

Ho Il Yoon  Myung Woo Han  Byong-Kwon Park  Jae-Kyung Oh  Soon-Keun Chang 《Marine Geology》1997,140(3-4):265-282

High-resolution (3.5 kHz and multi-channel) seismic profiles and piston cores were collected from Maxwell Bay and its tributary embayment, Marian Cove, in the South Shetland Islands, Antarctica, during the Korea Antarctic Research Program (1992/93 and 1995/96) to elucidate the glaciomarine sedimentation processes and recent glacial history of the area. Seismic data from Maxwell Bay reveal a rugged bay margin and flattened basin floor covered with well-stratified hemipelagic muds. On the base-of-slope, acoustically transparent debris flows occur, indicating downslope resedimentation of glaciomarine sediments. Despite the subpolar and ice-proximal settings of Marian Cove, the seafloor is highly rugged with a thin sediment drape, suggesting that much of the area has been recently eroded by glaciers. Sediment cores from the cove penetrated three distinct fining-upward lithofacies: (1) basal till in the lower part of the core, accumulated just seaward of the grounding line of the tidewater glacier; (2) interlaminated sand and mud in the middle part, deposited in ice-proximal zone by a combination of episodic subglacial meltwater inflow and iceberg dumping; and (3) pebbly mud in the upper part, deposited in ice-distal zone by both surface meltwater plume and ice-rafting from the glacier front. A reconstruction of the glacial history of these areas since the late glacial maximum shows an ice sheet filling Maxwell Bay in late Wisconsin time and grounding of the tidewater glacier in Marian Cove until about 1300 yr BP.  相似文献   

Three‐dimensional simulation of tsunami run‐up around conical island     

Byung Ho Choi  Dong Chule Kim  Efim Pelinovsky  Seung Buhm Woo 《Coastal Engineering》2007

At the circular Babi Island in the Flores tsunami (1992) and pear shaped island in the Okushiri event (1993), unexpectedly large tsunami run‐up heights in the lee of conic islands were observed. The flume and basin physical model studies were conducted in the Coastal Hydraulic Laboratory, Engineering Research and Development Center, U.S. Army Corps of Engineers to provide a better understanding of the physical phenomena and verify numerical models used in predicting tsunami wave run‐up on beaches, islands, and vertical walls. Reasonably accurate comparison of run‐up height of solitary waves on a circular island has been obtained between laboratory experimental results and two‐dimensional computation model results. In this study we apply three‐dimensional RANS model to simulate wave run‐up on conical island. In the run‐up computation we obtain that 3D calculations are in very good comparison with laboratory and 2D numerical results. A close examination of the three‐dimensional velocity distribution around conical island to compare with depth‐integrated model is performed. It is shown that the velocity distribution along the vertical coordinate is not uniform: and velocity field is weaker in the bottom layer and higher on the sea surface. The maximum difference (about 40%) appears at the time when solitary wave reached the circular island.  相似文献   

Wave reflection from partially perforated-wall caisson breakwater   总被引：2，自引：0，他引：2  

Kyung-Duck Suh  Jae Kil Park  Woo Sun Park   《Ocean Engineering》2006,33(2):264-280

In 1995, Suh and Park developed a numerical model that computes the reflection of regular waves from a fully perforated-wall caisson breakwater. This paper describes how to apply this model to a partially perforated-wall caisson and irregular waves. To examine the performance of the model, existing experimental data are used for regular waves, while a laboratory experiment is conducted in this study for irregular waves. The numerical model based on a linear wave theory tends to over-predict the reflection coefficient of regular waves as the wave nonlinearity increases, but such an over-prediction is not observed in the case of irregular waves. For both regular and irregular waves, the numerical model slightly over- and under-predicts the reflection coefficients at larger and smaller values, respectively, because the model neglects the evanescent waves near the breakwater.  相似文献   

格列菲列岛的地质地球物理研究     

CHOI Suckwon  Woo Youngkyun  Koo Minho  Suh Mancheol  郝天珧  王谦身 《地球物理学进展》2003,18(2):283-286

本文是中、韩国际合作项目“黄海地质地球物理场特征研究”的一部分 .具体研究了格列菲列岛的基础地质问题及地球物理场特征 .格列菲列岛是由三个小岛组成的位于黄海中部的一组群岛 ,位于朝鲜半岛布格重力异常正值区 ,莫霍面埋深在 2 9km左右 .三个岛屿主要由安山集块岩构成 .安山集块岩是由大小不同的火成岩碎块和熔岩混合而成 .火成岩的碎块成分主要为石英岩、片岩、片麻岩、玄武岩、安山岩和流纹岩 .主要节理方向为NE10°～NE2 0°,倾角近乎垂直 ;另一组节理为NW70°～NW80° ,倾角也近垂直 .本研究为我们了解这个地区的基础地质情况 ,岩石物性和随后进行的黄海海域典型剖面的地球物理物性反演工作以及地质模型的建立 ,打下重要基础 .  相似文献   

Towards an Interpretation of Historical Droughts in Northern Nigeria     

Aondover Tarhule  Ming-Ko Woo 《Climatic change》1997,37(4):601-616

Both historical information on sub-Saharan droughts/famines and measured rainfall data from northern Nigeria were analysed. Their parallel existence since 1905 allows famine chronologies to be quantified from the rainfall series. It is found that the most disruptive historical famines occurred when the cumulative deficit of rainfall fell below 1.3 times the standard deviation of long-term mean annual rainfall for a particular place. Thus defined, rainfall droughts matched approximately 90% of the famine events chronicled for northern Nigeria. An attempt is made to utilise information obtained from this matching of events to interpret droughts which occurred before scientific measurements. Difficulties inherent in such interpretation are discussed.  相似文献   

Constraints of Housing Age and Migration on Residential Mobility     

Dowell Myers  S. Simon Choi  Seong Woo Lee 《The Professional geographer》1997,49(1):14-28

This paper investigates the role of housing age in constraining residential mobility, measured as the percent of households that have moved into their homes in the past 15 months. The leading explanation for why mobility rates differ so much among regions of the United States has been the overall level of growth. The present analysis shows that the growth effect operates through both the newness of population (migration) and the newness of housing available for occupancy by all local residents. The posited explanation for this housing age effect is that progressively older units contain increasingly settled occupants, yielding fewer opportunities for in-movers in areas with older housing. It is empirically demonstrated that households in older housing have lower likelihood of recent mobility even after controlling for age, tenure, migration status, and state location of residence. The analysis reveals the temporal interdependency of mobility, migration, person age, and housing age.  相似文献