竖向入射S波作用下单桩水平地震响应简化解析方法

基于连续介质模型并考虑桩-土运动相互作用,将单桩视为一维线弹性梁,研究了竖向入射S波作用下的单桩水平地震响应问题。将竖向入射S波模拟为基岩水平位移,基于平面应变模型建立的土体控制方程,推导出地震作用下土体水平动力阻抗函数表达式。将土体阻抗代入单桩控制方程并联立桩-土接触条件及桩顶和桩底的边界条件,得出了竖向入射S波作用下单桩的地震响应解析解。通过将所得解与已有文献理论解和有限元结果进行对比,验证了该方法的合理性。基于所得理论解进行参数分析得出：桩-土模量比的增加可以明显降低桩-土运动相互作用因子的最小值,而较大桩身长径比以及土体滞回阻尼对桩-土运动相互作用因子的影响较小;对于桩顶水平地震放大因子来说,桩-土模量比的增加仅在高共振频率处抑制其幅值,较大桩身长径比对其影响较小,而滞回阻尼比的增加会显著抑制共振频率处的幅值;桩身地震响应仅在较小桩径比时受桩-土模量比的影响明显,并随桩-土模量比的增加而降低。     

甘肃省2000-2009年碳循环研究

对甘肃省2000-2009年的碳源和碳汇进行了研究,获得了该地区碳源、碳汇随时间变化的预测模型,并预测了未来的发展趋势.结果表明,甘肃省碳源由2000年的4.294 7×108 t/a逐年增加至2009年的5.6307×108t/a,10年间增加了31.11％.而同期碳汇由3.9595×108t/a逐年增加到4.8991×108t/a,仅增加了23.73％.显然,碳源的增加速率高于碳汇.甘肃省2000年碳失汇为0.3352×108t/a,2009年增至0.7316×108 t/a.预测甘肃省2015年碳源总量将达到6.7193×108t/a,碳汇总量为5.5487×108 t/a,碳失汇将达到1.1706×108t/a.显而易见,如不改变现有的发展模式,甘肃碳源与碳汇的失衡将不断加剧,碳安全面临更严峻的考验.     

济南市CO中毒的天气形势分析

利用2001-2003年济南市的CO中毒资料及同期高空、地面天气图,统计了CO中毒日的月、季变化特征,分析CO中毒事件所对应的天气形势背景,总结出8种高空风场和温度场的配置类型,在此基础上重点分析了各种类型所对应的地面气压场,结果表明:济南市采暖季节,CO中毒事件多发生在地面为南高北低、东高西低和维持时间较长的均压场和鞍型场的气压场中.风向、风速、气温、湿度等气象要素与CO中毒事件的发生有着一定的对应关系.     

Local-scale spatial variability of soil organic carbon and its stock in the hilly area of the Loess Plateau, China

Soil organic carbon (SOC) is one of the key components for assessing soil quality. Meanwhile, the changes in the stocks SOC may have large potential impact on global climate. It is increasingly important to estimate the SOC stock precisely and to investigate its variability. In this study, Yangjuangou watershed was selected to investigate the SOC distribution under different land uses. We found that SOC concentration decreased with increasing soil depth under all land uses and was significantly different across the vertical soil profile (P < 0.01). However, considering effect of land use on SOC, it is only significant (P < 0.01) in the topsoil (0-5 cm) layer. This indicated that land use has a large effect on the stocks of SOC in the surface soil. The stratification ratio of SOC > 1.2 may mean that soil quality is improving. The order of the SOC density (0-30 cm) under different land uses is forestland > orchard land > grassland > immature forestland > terraced cropland. The SOC stock is found to be as large as 2.67 × 10³ t (0-30 cm) in this watershed. Considering time effect of restoration, the slope cropland just abandoned is more efficient for SOC accumulation than trees planted in the semi-arid hilly loess area.     

Activity and Formation of Sand Waves on Northern South China Sea Shelf

Sand waves on the northern South China Sea shelf had been considered as stable relict bed form. For the industry use of sea bed between stations LF13-2 and LF13-1, a new round of explorations were conducted. The newly obtained data show that both spacings and amplitudes of sand waves are all systematically changing with water depth. Repeated observations since 2003 to 2004 showed that the sea bed is currently active. Due to strong erosion of surface sediment since Dongsha (东沙) uplifting, there are almost no...     

丹宁棉分离富集—发射光谱法同时测定地质样品中微量铌钽锆铪

采用丹宁棉对地质样品溶液中的铌、钽、锆、铪进行分离富集，将写信后的丹宁棉在600℃灼烧30min，灰分用发射光谱法同时测定四元素。检出限与通常的发射光谱法相比降低约2个数量级，经国家级标准物质检验，结果与标准值相符，精密度试验，各元素的RSD（n＝20）为2.6％－7.9％。     

四川底苏、大梁子铅锌矿床同位素地球化学特征及成矿物质来源探讨

本文通过底苏和大梁子铅锌矿床硫铅及氢氧同位素研究,认为同生沉积成岩成矿阶段矿石硫来源于赋矿围岩或同生沉积成岩成矿阶段矿层.矿石铅主要来源于矿区地层.改造热液中的水主要来自大气降水,成矿热液属大气降水含矿热液.     

水井的频率特性试验和对地震波的响应

前人用ＳＬＵＧ（殷积涛,郑香媛,１９９２）试验,根据渗流理论,由井水位的恢复曲线,计算水井含水层的渗透系数．我们在做ＳＬＵＧ试验时,对井水位的振荡产生兴趣．根据振动理论,由井水位的振荡曲线,不但计算了水井含水层的渗透系数,而且计算出水井含水层的频率参...     

高美古全夜视宁度的变化

介绍了云南丽江高美古天文候选点,１９９５年１２月～１９９６年１１月全夜视宁度观测结果：全年平均ｒ０＝１６．５０ｃｍ（ＦＷＨＭ＝０．６７″）,夜平均极大值ｒｍａｘ＝２２．４１ｃｍ（０．４９″）,夜平均极小值ｒｍｉｎ＝１２．９５ｃｍ（０．８５″）。     

丽江高美古天文候选点的气象观测

介绍了丽江高美古气象定点观测情况,给出了两年半天文可用时间及两年气象各因素的统计结果。