A small-scale energy release observed on the limb     

Ichiro Kawaguchi  Kap-Sung Kim  Yoshihiro Nakai 《Solar physics》1986,106(1):47-65

The D3 emission lines observed on the emerging flux loops and mound prominences above the limb were locally found to consist of two components, i.e., the main and the broadened components. A number of Doppler shifted emission lines, separated distinctly from the main body of the emission lines were also detected, which we call the separated components. On the sequential spectrograms, the lifetimes of these broadened and separated components were obtained and their histograms were made.We present the results of fitting the observed emission lines with the sum of two gaussian profiles in two simple cases under two different assumptions. In each assumption, it is found that the line-of-sight velocities of the broadened components with lifetimes shorter than 10 min monotonously increase with time and we attribute this behaviour to a single ejection of mass from the parent structures. In the broadened components with lifetimes longer than 10 min, the acceleration turns on and off alternately, each with a duration of several minutes. We attribute this behaviour to multiple ejections of mass.Finally, it is shown that the corona over the active region is supplied with enough mass for the formation of a coronal condensation if the ejected mass diffuses out high into the corona and some heating mechanisms for the mass switch on.Contributions from the Kwasan and Hida Observatories, University of Kyoto, No. 269.  相似文献   

A potentially pure test of cosmic geometry: galaxy clusters and the real space Alcock–Paczyński test     

Young-Rae Kim  Rupert A. C. Croft 《Monthly notices of the Royal Astronomical Society》2007,374(2):535-546

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Does upward seepage of river water and storm water runoff determine water quality of urban drainage systems in lowland areas? A case study for the Rhine–Meuse delta     

Kim Vermonden  Marion A. A. Hermus  Marije van Weperen  Rob S. E. W. Leuven  Gerard van der Velde  Alfons J. P. Smolders  Jan G. M. Roelofs  A. Jan Hendriks 《水文研究》2009,23(21):3110-3120

The water quality of urban drainage ditches in lowlands in the Rhine‐Meuse delta was analysed with principal component analysis (PCA) during a dry period and a rain storm, and related to the seepage of polluted river water and effective impervious area (EIA). This was done in order to test the hypothesis that seepage of river water and storm water runoff from impervious areas strongly determine the water quality of urban drainage systems along large lowland rivers. Our analysis revealed that upward seepage of groundwater originating from rivers Rhine and Meuse was positively correlated with nitrate, potassium, sodium and chloride and negatively correlated with alkalinity, calcium, magnesium and iron. EIA was correlated with very few environmental variables (i.e. phosphate, pH and iron in the dry period and iron during the rain storm). Nickel and zinc concentrations generally exceeded the maximum allowable concentrations (MAC), while lead and phosphorus concentrations were just above the nutrient standards and MAC in a few locations during the rain storm. To optimize water quality in urban water systems, attention should be paid to all sources of pollution and not only to EIA. The impact of local groundwater seepage originating from large rivers in lowlands on the chemistry of urban water systems is often underestimated and should be taken into account when assessing water quality and improving water quality status. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Distribution and long-term trends in various fog types over South Korea     

Miloslav Belorid  Chong Bum Lee  Jea-Chul Kim  Tae-Hun Cheon 《Theoretical and Applied Climatology》2015,122(3-4):699-710

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Interdecadal changes in summer TC activity in East China Sea     

Ki-Seon Choi  Yu-Mi Cha  Sung-Dae Kang  Hae-Dong Kim 《Theoretical and Applied Climatology》2015,120(1-2):11-18

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Climatological features of WRF-simulated tropical cyclones over the western North Pacific   总被引：2，自引：0，他引：2  

Dasol Kim  Chun-Sil Jin  Chang-Hoi Ho  Jinwon Kim  Joo-Hong Kim 《Climate Dynamics》2015,44(11-12):3223-3235

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Recent recovery of surface wind speed after decadal decrease: a focus on South Korea     

Kim  JongChun  Paik  Kyungrock 《Climate Dynamics》2015,44(5-6):1699-1713

Climate Dynamics - We investigate the multi-decadal variability of observed surface wind speed around South Korea. It is found that surface wind speed exhibits decreasing trend from mid-1950s until...  相似文献   

Estimation of turbulent sensible heat and momentum fluxes over a heterogeneous urban area using a large aperture scintillometer     

Sang-Hyun Lee  Jun-Ho Lee  Bo-Young Kim 《大气科学进展》2015,32(8):1092-1105

The accurate determination of surface-layer turbulent fluxes over urban areas is critical to understanding urban boundary layer (UBL) evolution. In this study, a remote-sensing technique using a large aperture scintillometer (LAS) was investigated to estimate surface-layer turbulent fluxes over a highly heterogeneous urban area. The LAS system, with an optical path length of 2.1 km, was deployed in an urban area characterized by a complicated land-use mix (residential houses, water body, bare ground, etc.). The turbulent sensible heat (Q H) and momentum fluxes (τ) were estimated from the scintillation measurements obtained from the LAS system during the cold season. Three-dimensional LAS footprint modeling was introduced to identify the source areas ("footprint") of the estimated turbulent fluxes. The analysis results showed that the LAS-derived turbulent fluxes for the highly heterogeneous urban area revealed reasonable temporal variation during daytime on clear days, in comparison to the land-surface process-resolving numerical modeling. A series of sensitivity tests indicated that the overall uncertainty in the LAS-derived daytime Q H was within 20%-30% in terms of the influence of input parameters and the non-dimensional similarity function for the temperature structure function parameter, while the estimation errors in τ were less sensitive to the factors of influence, except aerodynamic roughness length. The 3D LAS footprint modeling characterized the source areas of the LAS-derived turbulent fluxes in the heterogeneous urban area, revealing that the representative spatial scales of the LAS system deployed with the 2.1 km optical path distance ranged from 0.2 to 2 km2 (a "micro-α scale"), depending on local meteorological conditions.  相似文献   

Reactions of aqueous iron-DFOB (desferrioxamine B) complexes with flavin mononucleotide in the absence of strong iron(II) chelators     

Dongwook Kim  Owen W. Duckworth 《Geochimica et cosmochimica acta》2010,74(5):1513-6720

The mechanisms controlling microbial uptake of Fe^III-siderophore complexes and subsequent release of the metal for cellular use have been extensively studied in recent years. Reduction of the Fe^III center is believed to be necessary to labilize the coordinated Fe and facilitate exchange with cellular ligands. Previous studies report reduction of Fe^III-DFOB by various reducing agents in solutions containing Fe^II-chelating colorimetric agents for monitoring reaction progress, but the importance of these findings is unclear because the colorimetric agents themselves stabilize and enhance the reactions being monitored. This study examines the reduction of Fe^III complexes with DFOB (desferrioxamine B), a trihydroxamate siderophore, by the fully reduced hydroquinone form of flavin mononucleotide (FMN_HQ) in the absence of strong Fe^II-chelating agents, and Fe redox cycling in solutions containing DFOB and oxidized and reduced FMN species. Experimental results demonstrate that the rate and extent of Fe^III-DFOB reduction is strongly dependent on pH and FMN_HQ concentration. At pH ? 5, incomplete Fe^III reduction is observed due to two processes that re-oxidize Fe^II, namely, the autodecomposition of Fe^II-DFOB complexes (Fe^II oxidation is coupled with reduction of a protonated hydroxamate moiety) and reaction of Fe^II-DFOB complexes with the fully oxidized flavin mononucleotide product (FMN_OX). Chemical speciation-dependent kinetic models for the forward reduction process and both reverse Fe^II oxidation processes are developed, and coupling kinetic models for all three Fe redox processes leads to successful predictions of steady-state Fe^II concentrations observed over a range of pH conditions in the presence of excess FMN_HQ and FMN_OX. The observed redox reactions are also in agreement with thermodynamic constraints imposed by the combination of Fe^III/Fe^II and FMN_OX/FMN_HQ redox couples. Quantitative comparison between kinetic trends and changing Fe speciation reveals that FMN species react predominantly with diprotonated Fe^III-DFOB and Fe^II-DFOB complexes, where protonation of one hydroxamate group opens up two Fe coordination positions. This finding suggests that ternary complex formation (FMN-Fe-DFOB) facilitates inner-sphere electron transfer reactions between the flavin and Fe center.  相似文献   

When seed fails: The contested nature of neoliberalism in South Korea     

Sook-Jin Kim  Joel Wainwright 《Geoforum》2010,41(5):723-733

In recent years, many geographers have examined the ways that the production of nature has changed as a result of neoliberal practices. In this paper we examine a conflict in South Korea that started when some Chinese-cabbage seeds were affected by a virus, causing crop failure. This failure came shortly after liberalization in the Korean seed industry led to foreign ownership of the firm that sold the seed. We focus in particular on the farmers’ creative political responses - and their subsequent defeat in court. Drawing on Antonio Gramsci’s insights on politics, science, and law, we examine how the seed failure came to be evaluated through scientific and legal practices. We argue that the adjudication of the truth of the seed failure through science and law reveals how socionatures are contested under prevailing hegemonic conditions. These conditions are both general and specific: although law and science are relatively hegemonic spheres of truth-production in all capitalist societies, the ways that the seeds were disputed and evaluated were distinctly Korean.  相似文献