Lipids of sulfate-reducing bacteria and sulfur-oxidizing bacteria found in the Dongsheng uranium deposit

U-bearing sandstones from the Dongsheng deposit in Ordos Basin contain abundant C15-C18 fatty acids. The fatty acids may have been derived from modern and ancient organisms including organisms from the intervals of U mineralization. A certain amount of i15:0, a15:0, a17:0 fatty acids coexist with small amounts of i17:1ω7c and 10me16:0, characteristic biomarkers of Desulfovibrio and Desulfobacter sp., respectively. This indicates the existence of sulfate-reducing bacteria (SRB) in the sandstones. The presence of sulfur-oxidizing bacteria (SOB), such as Beggiatoa and Thioploca, is indicated by significant amounts of 16:1ω7c and 18:1ω7c fatty acids. The existence of the SRB in the deposit, as inferred from the fatty acids, is consistent with results from fossilized microorganisms and isotopic compositions of ore-stage pyrite. This suggests that the environment may have been favorable for the SRB to grow since ore formation (9.8-22 Ma). The bacteria may have degraded hydrocarbons directly, or indirectly utilized hydrocarbons degraded by oxic microbes in the deposits. This process may have produced 12C-rich calcite and prominent baseline humps of unresolved complex mixtures (UCM), and 25-demethylated hopanes and tricyclic terpanes. The existence of sulfur-oxidizing bacteria and sulfate-reducing bacteria in the deposit may have resulted in bacterial sulfate reduction to sulfide, re-oxidization of the sulfide to sulfate and subsequent reduction of the sulfate to sulfide. This assertion is supported by ore-stage pyrite with δ34S values as low as-39.2‰, and the lightest sulfate (about 11‰) measured during the Phanerozoic, a difference of more than 46‰.     

管式浆膜蒸发器新型板片改造与开发

从结构形式、热处理、材质选择等方面对新型管式浆膜蒸发器运行中出现的引起板片爆裂、泄露进行了研究分析;并就新型板片设计、制造、试验做出探索。     

Spatial prisoner’s dilemma games with increasing size of the interaction neighborhood on regular lattices

We studied the evolution of cooperation in the prisoner’s dilemma game on a square lattice where the size of the interaction neighborhood is considered. Firstly, the effects of noise and the cost-to-benefit ratio on the maintenance of cooperation were investigated. The results indicate that the cooperation frequency depends on the noise and cost-to-benefit ratio: cooperation reaches a climax as noise increases, but it monotonously decreases and even vanishes with the ratio increasing. Furthermore, we investigated how the size of the interaction neighborhood affects the emergence of cooperation in detail. Our study demonstrates that cooperation is remarkably enhanced by an increase in the size of the interaction neighborhood. However, cooperation died out when the size of the interaction neighborhood became too large since the system was similar to the mean-field system. On this basis, a cluster-forming mechanism acting among cooperators was also explored, and it showed that the moderate range of the neighborhood size is beneficial for forming larger cooperative clusters. Finally, large-scale Monte Carlo simulations were carried out to visualize and interpret these phenomena explicitly.     

Temporal and spatial distribution of tropospheric CO<Subscript>2</Subscript> over China based on satellite observations

Mid-troposphere CO₂ data retrieved by the AIRS (atmospheric infrared sounder) were validated with five ground-based stations and aircraft measurements in the Northern Hemisphere. AIRS CO₂ products show good agreement with ground and aircraft observations. The data had a monthly average accuracy better than 3 ppmv. In this study, the spatial and temporal distribution of mid-troposphere CO₂ from January 2003 to December 2008 was analyzed based on this satellite product. The average concentration of atmospheric CO₂ was higher in the Northern Hemisphere than in the Southern Hemisphere. The yearly average results show a gradual increase from 2003 to 2008. In China, the annual growth rate was about 2 ppmv/a, similar to the United States, Europe, Australia and India, but was slightly lower than Canada and Russia. Mid-troposphere CO₂ concentrations were higher over northern China than over southern areas, due to differences in natural conditions and industrial layout. There were four centers of high CO₂ concentration between 35° and 45°N over China, with low concentrations over Yunnan Province. There was a significant seasonal CO₂ variation with peak concentration in spring and the lowest concentration in autumn.     

论改善混凝土外掺剂与水泥适应性的措施

文章论述了水泥与外加剂的适应性是影响混凝土质量的重要因素,提出几点改善措施:即新型高性能减水荆的开发应用、外加剂的复合使用、减水剂的掺入方法、适当"增硫法"和适当调整混凝土配合比.     

县域经济发展中的居民消费研究

居民消费在县域经济发展中处于怎样的情况,文章就平鲁区居民消费的基本情况进行了分析.     

VOD法冶炼铁素体不锈钢的碳氮控制

文章介绍太钢第二炼钢厂利用K—OBM—S—VOD法生产超低碳铁素体不锈钢工艺特点，并对此类钢中409L型铁素体不锈钢在VOD法冶炼过程中的碳氮控制进行了总结研究。     

浅析如何加强电大的校园文化建设

当前,电大的发展面临严峻的挑战,如何在激烈的市场竞争中走出困境,长足发展,针对电大教育对象等几个方面的特殊性,文章从加强校园文化建设入手,在办学理念、加强校园网络文化建设、开展丰富的校园文化活动等几个方面作了实践性思考.     

“范式转换”与舞蹈学学科扩展

"范式转换"理论作为一种方法论,被其他学科领域借鉴来厘清所从事领域的发展、变迁路径以及把握其领域的未来走向。舞蹈学学科的扩展与多元发展也同样可用"范式转换"理论来解释并寻得探究的方法。舞蹈学学科范式的转换、舞蹈学学科对象、舞蹈学学科视角多元化几方面的阐述,说明在学科的建立和学术研究上不仅要有"范式的转换"的与时俱进,也应该有因地制宜的地方化特点,要尊重文化的差异性,提倡文化平等、多元。