The possible high-energy emission from GRB 080319B and origins of the GeV emission of GRBs 080514B, 080916C and 081024B

We calculate the high-energy (sub-GeV to TeV) prompt and afterglow emission of GRB 080319B that was distinguished by a naked-eye optical flash and by an unusual strong early X-ray afterglow. There are three possible sources for high-energy emission: the prompt optical and γ-ray photons IC scattered by the accelerated electrons, the prompt photons IC scattered by the early external reverse-forward shock electrons, and the higher band of the synchrotron and the synchrotron self-Compton emission of the external shock. There should have been in total hundreds of high-energy photons detectable for the Large Area Telescope onboard the Fermi satellite, and tens of photons of those with energy >10 GeV. The >10 GeV emission had a duration about twice that of the soft γ-rays. Astro-rivelatore Gamma a Immagini Leggero (AGILE) could have observed these energetic signals if it was not occulted by the Earth at that moment. The physical origins of the high-energy emission detected in GRB 080514B, GRB 080916C and GRB 081024B are also discussed. These observations seem to be consistent with the current high-energy emission models.     

基于综合气象干旱指数的中国干旱变化趋势研究

基于中国606个地面台站1951～2008年的逐日降水量和气温资料,采用综合气象干旱指数CI统计分析了中国全国及十大江河流域近60年的干旱变化趋势。结果表明,近60年来,从整体来看,中国干旱面积呈现出弱的增加趋势。干旱持续时间长的几个中心分别位于北方的辽河流域西部、黄河流域东部、海河流域、西南诸河流域东南部等地,最长持续时间可达4个月以上;北方江河流域干旱面积一般表现出增加趋势,其中松花江流域、辽河流域、海河流域干旱面积出现显著的增加趋势,辽河流域、海河流域、黄河流域在20世纪90年代中后期至21世纪前期连续数年出现大范围干旱,南方大多数江河流域干旱面积的变化趋势不明显,只有西南诸河流域有显著的减少趋势。     

Spatial dependence of diurnal temperature range trends on precipitation from 1950 to 2004

This paper analyzes the spatial dependence of annual diurnal temperature range (DTR) trends from 1950–2004 on the annual climatology of three variables: precipitation, cloud cover, and leaf area index (LAI), by classifying the global land into various climatic regions based on the climatological annual precipitation. The regional average trends for annual minimum temperature (T _min) and DTR exhibit significant spatial correlations with the climatological values of these three variables, while such correlation for annual maximum temperature (T _max) is very weak. In general, the magnitude of the downward trend of DTR and the warming trend of T _min decreases with increasing precipitation amount, cloud cover, and LAI, i.e., with stronger DTR decreasing trends over drier regions. Such spatial dependence of T _min and DTR trends on the climatological precipitation possibly reflects large-scale effects of increased global greenhouse gases and aerosols (and associated changes in cloudiness, soil moisture, and water vapor) during the later half of the twentieth century.     

Stable carbon isotopes of alkane gases from the Xujiahe coal measures and implication for gas-source correlation in the Sichuan Basin,SW China

The Upper Triassic Xujiahe Formation in the Sichuan Basin, SW China consists of a series of coal measures. The first, third and fifth members of this formation are dominated by gas prone dark mudstones and coals. The mudstones contain Type II and III kerogens with average organic carbon contents around 1.96%. These source rocks are mature in the central Sichuan and highly mature in the western Sichuan Basin, characterized by gas generation with subordinate amounts of light oil or condensate oils. The source rocks are intercalated with the sandstone dominated second, fourth and sixth members of the Xujiahe Formation, thus leading to three separate self contained petroleum systems in the region. The proven gas reserves in the Xujiahe Formation are only less than that of the Triassic Feixianguan Formation and the Xujiahe Formation has the second largest gas field (Guang’an gas field) in the basin. Gases derived from the Xujiahe Formation coals generally show a normal stable carbon isotopic trend for C₁–C₄ n-alkanes, with the highest δ¹³C₂ values among the nine gas pay zones in the basin (?20.7‰ to ?28.3‰), and δ¹³C₁ values as low as ?43.0‰ in the central Sichuan. Gas accumulations with an oil leg have also been found in the eastern and southern Sichuan where the thickness of the Xujiahe Formation is significantly reduced. Gases in these accumulations tend to show low δ¹³C₂ values (?30.0‰ to ?36.3‰), characteristic of oil prone source rocks.     

The clustering properties of Luminous Red Galaxies

By cluster analysis, we study the clustering properties of Luminous Red Galaxies (LRGs) and compare them with those of Main galaxies. We find that the clustering properties of Luminous Red Galaxies is different from those of Main galaxies, and that LRGs cluster mainly in form of close double and multiple galaxies, galaxy groups. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

China's Lunar Exploration Program: Present and future

China launched its first lunar probe, Chang’E-1, at 6:05 p.m. (10:05 GMT), October 24, 2007. Chang’E-1 blasted off on a Long March 3A carrier rocket from the No. 3 launch tower in the Xichang Satellite Launch Center of southwestern Sichuan Province. China National Space Administration performed the lunar orbit injection maneuver for Chang’E-1 at 11:25 a.m. on November 5, 2007 (China Standard Time). Chang’E-1 was injected into the lunar orbit after the maneuver, and will begin to explore the moon in the following 1 year. It is the first step into its ambitious three-phase moon mission, marking a new milestone in the Chinese space exploration history.     

斯堪的纳维亚臭氧亏损和物质输送

冬季在北极的斯堪的纳维亚地区存在一个明显的臭氧亏损区,亏损区的中心值达-50 DU.对臭氧亏损和地面温度进行相关分析后指出:斯堪的纳维亚地区的臭氧亏损和该地区地面温度和地面热通量关系极其密切,进一步分析物质的向上输送表明冬季斯堪的纳维亚地区的臭氧亏损可能是由于地面加热引发的物质抬升所造成的.     

印度洋珊瑚岛礁地基动力特性测试分析

依托印度洋岛国马尔代夫维拉纳国际机场的跑道建设项目,进行了珊瑚岛礁吹填地基动力特性测试,揭示了珊瑚砂地基的振动特性,为机场跑道地基处理方法的选定提供了基础资料。     

High‐precision Determination of Gold Mass Fractions in Geological Reference Materials by Internal Standardisation

Determination of gold abundances in natural rock is critical for applications, but very challenging. Here, we report a method for determining gold with a very low mass fraction (> 0.01 ng g^?1) in rocks. The method involves Carius tube digestion with reverse aqua regia, chromatographic separation to remove most of the sample matrix and measurement by high‐sensitivity ICP‐MS. The mono‐isotopic element gold was quantified by external calibration using an internal standardisation of gold to platinum that was precisely determined by isotope dilution. The method is robust and the obtained results are indistinguishable (< 5–10%, 2s) from those independently obtained by a standard addition technique on the same solution. The results from reference materials TDB‐1 and GPt‐2 are consistent with the certified values and those determined by HF‐aqua regia digestion, confirming the validity of the method. TDB‐1 (n = 20), GPt‐2 (n = 6), BHVO‐2 (n = 9) and other mafic RMs are homogenous for gold (10–20%, 2s) at the 2 g test portion level; however, sample heterogeneity affects some RMs. Gold and platinum‐group elements also display different extents of sample heterogeneity for different RMs. Given the homogeneity observed for TDB‐1, GPt‐2 and BHOV‐2, they are recommended as well‐suited RMs for inter‐laboratory comparison studies of gold.