X-ray observations of galaxy clusters have played an important role in cosmology, especially in determining the cosmological density parameter and the fluctuation amplitude. While they represent the bright side of the universe together with the other probes including the cosmic microwave background and the Type Ia supernovae, the resulting information clearly indicates that the universe is dominated by dark components. Even most of cosmic baryons turns out to be dark. In order to elucidate the nature of dark baryons, we propose a dedicated soft-X-ray mission, DIOS (Diffuse Intergalactic Oxygen Surveyor). Recent numerical simulations suggest that approximately 30 to 50 percent of total baryons at z = 0 take the form of the warm-hot intergalactic medium (WHIM) with 105K < T < 107K which has evaded the direct detection so far. The unprecedented energy resolution (~ 2eV) of the XSA (X-ray Spectrometer Array) on-board DIGS enables us to identify WHIM with gas temperature T = 106 ~ 107K and overdensity δ = 10 ~ 100 located at z < 0.3 through emission lines of OVII and OVIII. In addition, WHIMs surrounding nearby clusters are detectable with a typical exposure time of a day, and thus constitute realistic and promising targets for DIOS.

X-ray plasma ejections often occurred around the impulsive phases of solar flares and have been well observed by the SXT aboard Yohkoh. Though the X-ray plasma ejections show various morphological shapes, there has been no attempt at classifying the morphological groups for a large sample of the X-ray plasma ejections. In this study, we have classified 137 X-ray plasma ejections according to their shape for the first time. Our classification criteria are as follows: (1) a loop type shows ejecting plasma with the shape of loops, (2) a spray type has a continuous stream of plasma without showing any typical shape, (3) a jet type shows collimated motions of plasma, (4) a confined ejection shows limited motions of plasma near a flaring site. As a result, we classified the flare-associated X-ray plasma ejections into five groups as follows: loop-type (60 events), spray-type (40 events), jet-type (11 events), confined ejection (18 events), and others (8 events). As an illustration, we presented time sequence images of several typical events to discuss their morphological characteristics, speed, CME association, and magnetic field configuration. We found that the jet-type events tend to have higher speeds and better association with CMEs than those of the loop-type events. It is also found that the CME association (11/11) of the jet-type events is much higher than that (5/18) of the confined ejections. These facts imply that the physical characteristics of the X-ray plasma ejections are closely associated with magnetic field configurations near the reconnection regions.

We have developed a two fluid solar wind model from the Sun to 1 AU. Its basic equations are mass, momentum and energy conservations. In these equations, we include a wave mechanism of heating the corona and accelerating the wind. The two fluid model takes into account the power spectrum of Alfvenic wave fluctuation. Model computations have been made to fit observational constraints such as electron(Te) and proton(Tp) temperatures and solar wind speed(V) at 1 AU. As a result, we obtained physical quantities of solar wind as follows: Te is 7.4 X 10.5 K and density(n) is 1.7 X 107 cm-3 in the corona. At 1 AU Te is 2.1 X 105 K and n is 0.3 cm-3, and V is 511 km s-1. Our model well explains the heating of protons in the corona and the acceleration of the solar wind.

It has been a big mystery what drives filament eruptions and flares. We have studied in detail an X1.8 flare and its associated filament eruption that occurred in NOAA Active Region 9236 on November 24,2000. For this work we have analyzed high temporal (about 1 minute) and spatial (about 1 arcsec) resolution images taken by Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory, Hα centerline and blue wing (-0.6Å) images from Big Bear Solar Observatory, and 1600 Å UV images by the Transition Region and Corona Explorer (TRACE). We have found that there were several transient brightenings seen in Hα and, more noticeably in TRACE 1600 Å images around the preflare phase. A closer look at the UV brightenings in 1600 Å images reveals that they took place near one end of the erupting filament, and are a kind of jets supplying mass into the transient loops seen in 1600 Å. These brightenings were also associated with canceling magnetic features (CMFs) as seen in the MDI magnetograms. The flux variations of these CMFs suggest that the flux cancellation may have been driven by the emergence of the new flux. For this event, we have estimated the ejection speeds of the filament ranging from 10 to 160 km s-1 for the first twenty minutes. It is noted that the initiation of the filament eruption (as defined by the rise speed less than 20 km s-1) coincided with the preflare activity characterized by UV brightenings and CMFs. The speed of the associated LASCO CME can be well extrapolated from the observed filament speed and its direction is consistent with those of the disturbed UV loops associated with the preflare activity. Supposing the Hα/UV transient brightenings and the canceling magnetic features are due to magnetic reconnect ion in the low atmosphere, our results may be strong observational evidence supporting that the initiation of the filament eruption and the preflare phase of the associated flare may be physically related to low-atmosphere magnetic reconnection.

본 연구는 사람의 시험관아기 프로그램에서 수정 후 1일째의 전핵 등급이 체외 수정란의 발달에 미치는 영향을 조사하였다. 정상적인 시험관 아기 시술을 시행한 실례 환자를 대상으로 과배란을 유기하여 배란 직전의 난자를 채취하여 정자를 주입한 다음 체외 수정을 유도하였다. 수정 유도 18시간 후 전핵과 핵인의 형태에 따라 전핵의 등급을 1 및 2등급으로 나누어 각각 3일 동안 체외 배양을 실시하여, 체외 수정란의 형태에 따라 1, 2 및 3등급으로 분류하였든

본 연구는 사람의 시험관아기 프로그램에서 체외 수정란의 질을 향상시키는 한 방법으로 난포액으로 처리된 정자를 체외 수정에 사용하여 생산된 체외 수정란의 전핵 등급과 발달 능력을 조사하였다. 정상적인 시험관 아기 시술을 시행한 실례 환자를 대상으로 과배란을 유기하여 배란 직전의 난자를 채취하여, 난포액으로 처리된 정자와 체외 수정시킨 후 사람 체외 수정란의 전핵 등급과 체외발달율을 조사하였다. 체외수정을 위한 정자의 처리 방법으로 synthetic ser

In this paper, we review recent studies on the magnetic helicity changes of solar active regions by photospheric horizontal motions. Recently, Chae(200l) developed a methodology to determine the magnetic helicity change rate via photospheric horizontal motions. We have applied this methodology to four cases: (1) NOAA AR 8100 which has a series of homologous X-ray flares, (2) three active regions which have four eruptive major X-ray flares, (3) NOAA AR 9236 which has three eruptive X-class flares, and (4) NOAA AR 8668 in which a large filament was under formation. As a result, we have found several interesting results. First, the rate of magnetic helicity injection strongly depends on an active region and its evolution. Its mean rate ranges from 4 to 17 × 10 40 Mx2 h-1. Especially when the homologous flares occurred and when the filament was formed, significant rates of magnetic helicity were continuously deposited in the corona via photospheric shear flows. Second, there is a strong positive correlation between the magnetic helicity accumulated during the flaring time interval of the homologous flares in AR 8100 and the GOES X-ray flux integrated over the flaring time. This indicates that the occurrence of a series of homologous flares is physically related to the accumulation of magnetic helicity in the corona by photospheric shearing motions. Third, impulsive helicity variations took place near the flaring times of some strong flares. These impulsive variations whose time scales are less than one hour are attributed to localized velocity kernels around the polarity inversion line. Fourth, considering the filament eruption associated with an X1.8 flare started about 10 minutes before the impulsive variation of the helicity change rate, we suggest that the impulsive helicity variation is not a cause of the eruptive solar flare but its result. Finally, we discuss the physical implications on these results and our future plans.

We have examined the relationship between the speeds of coronal mass ejections (CMEs) and the GOES X-ray peak fluxes of associated flares. Noting that previous studies were possibly affected by projection effects and random association effects, we have considered two sets of carefully selected CME-flare events: four homologous events and four well-observed limb events. In the respective samples, good correlations are found between the CME speeds and the GOES X-ray peak fluxes of the associated flares. A similarly good correlation is found for all eight events of both samples when the CME speeds of the homologous events are corrected for projection effect. Our results suggest that a close relationship possibly exists between CME kinematics and flaring processes.