Advances of Soil Microbiology in the Last Decade in China

Soils are fundamental to preservation and sustainability of life-support system on Earth. Soils develop as the most dynamic and complex interface linking atmosphere, hydrosphere, lithosphere and biosphere. Soils harbor enormous diversities of microbial communities as the primary driving forces for global exchanges of matter and energy on our planet. Despite of its profound importance, the invisible soil microbes have for long been underappreciated. In the early 2000s, there has been growing awareness that soil microbiology has attracted huge interest from nonsoil scientists due to the introduction of three domain phylogeny. It is also known as tree of life theory which is widely recognized as the most accurate reflection of the relatedness of all organisms and provides us with a tool to classify and elucidate the largely untapped resource of soil microbial communities. In January 2005, the Department of Earth Sciences of National Natural Science Foundation of China organized a workshop of ‘Soil Biology and Soil Processes’ with focused discussion on soil microbiology research frontiers. The workshop outlined research priorities, cross disciplinary research opportunities, technological needs and potential breakthroughs within soil microbiology. This workshop has witnessed the rapid advances of soil microbiology in soil nutrient transformation, global environmental changes and environmental remediation over the last decade in China. This article will give a brief review on soil microbial researches in the past decade in China, present the status quo of funding system and highlight the challenge and opportunities for future soil microbiology in China.     

桩-土间剪切应力的传递探讨

对不同情况下桩-土间剪切应力进行了初步的理论分析,并基于ADINA有限元程序,对不同情况下的桩-土间剪切应力进行了计算对比分析。结果表明,同种土体和桩体条件下,各种模式达到极限状态时桩-土间剪切应力不同,堆载作用下负摩擦力值最大,抗拔桩负摩阻力值最小,桩顶受压桩、托桩的摩阻力值介于其间;桩材泊松比在0.15～0.35范围内时,桩侧摩阻力随泊松比的增大而增大。所得结论有助于进一步认识桩-土相互作用规律以及桩-土荷载传递机制。     

喷混凝土边坡温度场与应力场耦合的有限元时效分析

由于混凝土材料与岩土材料的热传导系数、比热容与热膨胀系数的差异,在温度的循环变化下使得喷射混凝土边坡容易于喷层与岩土层的结合面处产生应力集中而开裂。采用有限元的方法,考虑地应力与温度应力的耦合作用,分析了在一定的边界温度作用下不同时刻边坡喷层面的水平位移,以及喷层与岩层结合面处的剪应力的分布规律;指出在温度应力与地应力的共同作用下,喷混凝土边坡坡顶与坡脚均为容易发生破坏的地方,通常坡顶的破坏型式为拉张破坏而坡脚则为剪切破坏;边坡内的温度分布、边坡表面的位移与应力的变化均存在一定的时间效应,这一规律与实测规律比较吻合。分析结果表明,当温度变化剧烈时边坡的防护必须考虑温度应力的影响。     

Determination of internal pressure of synthetic fluid inclusions in the H2O-CH4 system using Raman spectroscopy

Determination of internal pressure of synthetic fluid inclusions in the H_2O-CH_4 system using Raman spectroscopy     

1999年我国天气气候特点

１９９９年我国主要天气气候特点可概括为：大部地区冬春连旱,夏季南涝北旱,秋季旱渍并存。全国持续偏暖,但幅度已较１９９８年有所下降,而且阶段性变化也更趋明显,部分地区遭受了高温或低温霜冻危害。热带风暴生成和登陆我国的个偏省;沙尘暴异常偏早;风雹偏省,损失轻;雾日较多。     

Evidence for solar forcing of climate variation from δ18O of peat cellulose

There have been a number of investigations for examining the possible link between long-term climate variability and solar activity. A continuous δ¹⁸O record of peat cellulose covering the past 6 000 years and the response of climate variation inferred from the proxy record to solar forcing are reported. Results show that during the past 5 000 years the abrupt climate variations, including 17 warming and 17 cooling, and a serious of periodicities, such as 86, 101, 110, 127, 132, 140, 155, 207, 245, 311, 820 and 1 050 years, are strikingly correlative to the changes of solar irradiation and periodicity. These observations are considered as further evidence for a close relationship between solar activity and climate variations on time scales of decades to centuries.     

岩石圈流变实验研究的进展

岩石高温高压变形实验是了解地球内部物质流动特性的最直接的手段 .本文概述了近年来岩石流变实验研究的一些成果 ,重点总结了水和部分熔融对上地幔顶部橄榄石流变行为的影响 ,以及地壳多相岩石流变实验研究的一些成果 .     

试论气候异常对重大工程建设的影响

依据大量实例阐明了气候与重大工程建设的关系,以及气候异常变化对重大工程的影响,指出了在重大工程建设中因未考虑气候异常变化所带来的严重后果.提出在重大工程规划、设计和建设中应注意的气候灾害问题.     

叠前时间偏移方法在煤田勘探中的应用

根据克希霍夫积分法的原理,介绍了叠前时间偏移的方法特点,实现过程,以及对地震资料的要求,依托国家重大产业技术专项“西部煤炭资源高精度三维地震勘探”工程,对“青海省鱼卡煤田四井田高精度三维地震勘探”资料进行叠前时间偏移,结果表明其能较好地解决成像质量差、能量聚焦不明显、绕射波收敛不理想等方面的难题。通过与叠后时间偏移对比,对于大倾角地层、断块小且多的破碎带、陡倾角不对称向斜等地质问题,其叠前时间偏移剖面成像质量都有明显的提高,反映的构造关系更加清晰,同相轴连续性增强。总结该方法在多个矿区的推广经验．认为合理的观测系统、较高的资料信噪比,准确的测量资料及较高的中表层速度调查精度是做好叠前时间偏移的前提。     

基于多元回归分析的铬污染地下水风险评价方法

土-水分配系数（K_d）是表征重金属污染物在土壤包气带中迁移能力的重要参数,受污染物质量浓度、pH值、有机质质量分数、铁铝氧化物质量分数等多种因素影响。本文通过实验研究了分配系数与各种影响因素之间的关系,基于多元回归分析方法得到了分配系数与影响因素的关系方程;并以分配系数、泄漏量、土壤孔隙度、初始含水率为风险因子建立了地下水污染风险评价方法。以某工厂铬废液的泄露为案例,采用构建的方法进行地下水污染风险评价。结果表明：该处地下水被污染的风险等级为中等。地下水污染风险评价方法的建立为重金属污染地下水的监测管理提供了一种有效方法。