SULFUR IX TO XIII SPECTRAL MEASURMENTS BETWEEN 170 AND 500Å

This paper reports laboratory measurements of the spectrum of highly ionized sulfur. The spectrum of S Ⅸ–S ⅩⅢ has been observed in the wavelength range 170–500 Å. A total of 54 lines have been measured. Forty-two of them have been classified as 2s22pk–2s2pk+1and 2s2pk–2pk+1 transitions. Twelve other lines have been ascribed to 2s–2p,4p–5s,5p–6s,5d–6p, and 6p–8d transitions. These spectral lines have been identified, among which 22 are new and accurately measured. The analysis of the spectra was based on a comparison with other experimental results and calculated values.

Precipitation at Lake Qinghai；NE Qinghai-Tibet Plateau；and its relation to Asian summer monsoons on decadal/interdecadal scales during the past 500 years

IEECAS SKLLQG

Vegetation and climate variations at Taibai, Qinling Mountains in central China for the last 3 500 cal BP

IEECAS SKLLQG

Double ionization of helium in collision with 20-500-keV/amu Cq+ and Oq+ (q=1-3) ions

Target ionization and projectile charge changing were investigated for 20-500 keV/u Cq+, Oq++He (q=1-3) collisions. Double- to single-ionization ratios R-21 of helium associated with no projectile charge change (direct ionization), single-electron capture, and single-electron loss were measured. The cross-section ratio R-21 depends strongly on the collision velocity v, the projectile charge state q, and the outgoing reaction channel. Meanwhile, a model extended from our previous work [J. X. Shao, X. M. Chen, and B. W. Ding, Phys. Rev. A 75, 012701 (2007)] is presented to interpret the above-mentioned dependences. Good agreement is found between the model and the experimental data.

湖北省近500年区域干湿序列重建及其比较分析

在历史旱涝记载资料可靠性检验的基础上,重建了湖北省3个区域近500年来的干湿气候变化序列,并比较分析了各区域干湿气候变化的趋势特征、准周期性及跃变现象。结果表明:在3个区域中,鄂东区1570~1770、1890~1950年两个时段偏湿,1470~1520、1790~1830年则偏干;鄂北区偏湿时期主要在1470~1530、1710~1750、1850~1910年三个时段,1470~1530、1770~1830年则偏干;鄂西南区有1550~1610、1650~1710、1830~1890、1930~1990

Cold event at 5 500 a BP recorded in mud sediments on the inner shelf of the East China Sea

A 700-year record (1.0-1.5 a resolution) of the East Asian winter monsoon (EAWM), based on grain-size analysis and AMS(14)C dating of Core EC2005 from the inner-shelf mud wedge of the East China Sea (ECS), was compared with the Dongge stalagmite delta O-18 record during the mid-Holocene. The upper muddy section of Core EC2005 has been formed mainly by suspended sediments derived from the Changjiang (Yangtze) River mouth since 7.3 ka BP. High precipitation and a strengthened EAWM might have played key roles in the high sedimentation rate (1 324-1 986 cm/ka) between 5.9-5.2 ka BP. The EAWM strengthened when the Asian summer monsoon weakened, especially around 5 500 a BP, which corresponded to a worldwide cold event. The EAWM during the mid-Holocene shows statistically significant solar periodicities at 62 and 11 a. The 5 500 a BP cold event might be resulted from orbital forcing and changes in solar activity.

甘肃西峰黄土剖面500 ka以来的蜗牛化石记录及其古气候、古环境变化研究

The loess-paleosol sequences in China are among the best continental records of paleoclimate changes. Although numerous sedimentological and geochemical studies have contributed greatly to the understanding of past climate changes during this period, it is still necessary to decipher more details through investigating these sequences using various approaches including biological analyses. In this study, we analyze the mollusk fossil assemblages preserved in the upper part of the Xifeng section, from the fifth loess layer (L5) to the Holocene soil (S0), with the sampling interval of 10 cm. The main results and conclusions obtained are as follows: 1. A continuous terrestrial mollusk fossil record, covering the past 500 ka, has been obtained from the Xifeng loess-paleosol sequence, which provides important biological data for the study of paleoenvironmental changes in the Loess Plateau and its comparison with marine record during this period. A total of 475 mollusk assemblages were studied, and twenty-one species have been identified among the 210,000 mollusk individuals counted. Among these species, most have modern representatives and are found in previous terrestrial mollusk studies of Chinese loess-paleosol sequences. Thus, they can be grouped into cold-aridiphilous, thermo-humidiphilous, oriental, and cool-humidiphilous ecological groups, as defined by previous studies. 2. Comparison of mollusk assemblages between the last five glacials and four interglacials and Holocene shows very different climate conditions. The warmest period occurred at MIS 11, MIS 5e, and Holocene, respectively. The coldest period is the Last Glacial Maximam, rather than the MIS 12. 3. Our mollusk record provides insight into the climate conditions in the Loess Plateau during the MIS 11, interpreted as the closest analog to the present interglacial. S4 paleosol, equivalent of MIS 11, developed under two major different climate regimes: ranging from the very warm–humid early phase to the mild-cool late interval. Furthermore, a cooling spell has been documented at the interglacial optimum, reflecting unstable climate conditions. The early warm–humid conditions lasted over 30 ka, supporting that MIS 11 is a unique long interglacial in the Quaternary climate history. 4. Comparison of MIS 11 and Holocene climates based on the mollusk species compositions indicates major differences. The climate at the early part of MIS 11 was warmer and more humid than during the Holocene optimum period, but the conditions during the late part of MIS 11 were similar to or cooler than late Holocene. Our study indicates that the extent of warming during the Holocene might be significantly less than the conditions that prevailed during the early part of MIS 11 interglacial period. 5. Two strong summer monsoon events were observed during the MIS 12 and MIS 10. They correspond to the maximam values of insolation gradient between low and high latitudes, suggesting a causal linkage. 6. Our study, combined with the previously investigated Luochuan land snail record, reveals that the climate in the Loess Plateau during MIS 3 experienced three stages: relatively warm, humid climate prevailed during MIS 3c, relatively cold, dry climate during MIS 3b, and relatively warm-humid period during MIS 3a. Climate at this time fluctuated frequently in Luochuan, and changed from warm-cool to cold-dry in Xifeng. Our results reveal that the relatively warm-humid climate during MIS 3c may be resulted from an increasing insolation gradient controlled by obliquity. Our result also reveals that obvious regional difference existed in the Loess Plateau during MIS 3. A greater climate gradient occurred during this time compared with today’s climate pattern in the Loess Plateau.

Caracterização dos problemas de fitoxicidade de plântulas de soja devido ao tratamento de sementes com fungicida rhodiauram 500 SC, na safra 2000/01.

Identificacao dos sintomas de fitotoxicidade; Decisao quanto a semeadura; Importancia da manutencao da tecnologia do tratamentodesementes de soja com fungicidas; Outros problemas que tem ocorrido simultaneamente nas lavouras.

Demonstration thermo-electric and MHD mathematical models of a 500 kA A1 electrolysis cell

In the present study, a 3D full cell quarter thermo-electric model of a 500kA demonstration cell has been developed and solved. In parallel, a non-linear wave MHD model of the same 500 kA demonstration cell has been developed and solved. A preliminary study of the impact of the interactions between the cell thermo-electric and MHD models will be presented.

Impact of the vertical potshell deformation on the MHD cell stability behavior of a 500 kA aluminium electrolysis cell

In previous publications [1,2], it was rationalized that a large vertical potshell deformation may have a negative impact on the operations of very high amperage cells. The MHD-Valdis non-linear Magneto-Hydro-Dynamic model was therefore extended to take into account the displacement of the potshell. The MHD cell stability behavior of a 500 kA cell with a 17.3 meters long potshell was then studied.