重力坝抗震安全评价中有限元梁杆体系新模型的适用性

传统的材料力学法静动力分析一直是我国重力坝规范规定的重力坝抗震安全评价的基本依据。但为了简化传统经典的重力坝材料力学法模型在动力分析中的复杂度,近年来,随着有限元分析技术的日益推广,许多重力坝有限元梁杆体系新模型在工程界开始得到应用,部分替代了传统材料力学法模型的作用,并在考虑多向地震耦合问题方面体现了一定的优势。从材料力学法的基本定义出发,提出了一种合理的坝面载荷处理模式,并从模态、抗侧力刚度、坝顶位移、内力结果等方面建立适用度指标,对这些有限元新模型进行细致对比,建议了一种最优的有限元梁杆模型,由该模型得到的结果与传统材料力学法的结果吻合,因此可供工程借鉴。     

华南下扬子区下奥陶统仑山组:岩石学、地层学和古地理学*

华南地区下奥陶统仑山组为奥陶系最底部的岩石地层单位之一,其以大套白云岩为主要特征,广泛分布于下扬子区。通过对安徽池州洪家剖面仑山组的系统分析,并结合下扬子区多个相关剖面的资料,进一步确定仑山组岩性为白云岩、灰质白云岩和白云质灰岩,夹有部分亮晶颗粒灰岩和亮泥晶颗粒灰岩。整体上以亮晶生屑灰岩或泥晶生屑灰岩的出现作为仑山组顶界,在下扬子区内部、北部及东南部地区以白云质灰岩或灰质白云岩出现为其底界,而在下扬子区西南部大部分地区则以白云岩化出现为其底界。整个仑山组所含生物化石种类和数量较少,自下而上可建立5个牙形石带,分别是Monocostatus sevierensis带、Acanthodus lineatus-A. costatus带、Scolopodus? pseudoplanus带、Glyptoconus quadraplicatus带和Paltodus deltifer-Tripodus proteus带,推测其时代为早奥陶世特马豆克早期。仑山组主要形成于浅潮下带至深潮下带环境中,其地层总厚度和其中的白云岩厚度受到古地理因素的控制。通过岩石学特征分析,推断仑山组白云岩主要为准同生条件下的多种白云岩化作用叠加中等埋藏条件下的白云岩化形成。     

Spatial disparity and efficiency of science and technology resources in China

In the knowledge economy era,science and technology(S&T) resources are getting more and more important in shaping regional competiveness and building regional innovation capacity.As such,the spatial distribution of S&T resources is a key to understanding regional development and disparities.By designing an input-output indicator system,this paper develops an evaluation model to examine the spatial distribution of S&T resources in China and assess their spatial efficiency.Moreover,the paper tries to explain spatial differences in the efficiency of S&T resources in China.Major findings are:1) the input and output of S&T resources in China shows a clear T-shaped spatial structure,i.e.,concentrated mainly in the coastal region and along the Changjiang(Yangtze) River;2) the efficiency of S&T resources in China displays strong spatial disparities,with the level of efficiency descending from the east to the west while high efficiency appearing in only several clusters;3) the utilization rates of S&T resources in most provinces are quite low,resulting in low efficiency of S&T resources allocation.The paper suggests that the utilization rate of S&T resources should be raised and the commercialization of S&T outputs should be enhanced to improve the efficiency of S&T resources in China.     

Sorption of perfluorooctane sulfonate (PFOS) on marine sediments

Sorption of anionic perfluorooctane sulfonate (PFOS) on marine sediment was investigated in detail. It was found that solution ionic composition and sediment-specific parameters played important roles in affecting the sorption of PFOS. The results indicated that sorption of PFOS in seawater to marine sediments was strong (≈ 10 times higher than that in freshwater) and nonlinear (Freundlich n(F) values of 0.77-0.96). The sorption affinity was well correlated with sediment organic carbon content, indicating the importance of hydrophobic interactions. At a PFOS aqueous concentration of 10 μg/L, PFOS distribution coefficients increased with the increasing salinity in solution, with an average rate of 0.48 ± 0.03 log units per a log unit of salinity. Further studies demonstrated that among common ions contributing to the salinity in seawater, dissolved calcium and magnesium are dominantly responsible for the sorption-enhancing effect of salinity for PFOS. This work will aid in better understanding of PFOS sorption mechanisms, and be useful for fate modeling of this class of contaminants in the marine environment.     

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二氧化氯作用下的煤吸附性变化及其大分子结构响应

采用二氧化氯溶液浸泡、甲烷等温吸附、X射线衍射等方法,探讨了煤储层改造新原理,从大分子结构层次上讨论了其可能的地球化学机理。实验结果显示,煤经浸泡后其吸附常数发生了明显变化,含气饱和度、临界解吸压力等得到不同程度的提高,但提高的程度受煤级控制。经二氧化氯处理后,煤中大分子结构单元发生了程度不等的解聚作用,煤大分子结构与吸附性之间存在同步响应关系,二氧化氯残液中存在苯环等有机物,解聚程度与煤化作用程度有关。浸泡后,煤分子结构发生了改变,使得其表面性质出现变化,从而影响到煤对甲烷分子的吸附能力和煤层气解吸产出潜势。     

2014 年2 月12 日新疆于田MS 7. 3地震震害调查分析

2014 年2 月12 日新疆于田县发生MS7. 3 地震,发震构造初步判断为阿尔金断裂带。推测极震区烈度为Ⅸ度,位于无人区;Ⅵ、Ⅶ度区为现场调查确定,共216 个烈度调查点。地震造成新疆和田地区和巴音郭楞蒙古自治州7 个县(市)的39 个乡、镇(场)的房屋、市政和交通设施、农牧业基础设施等受到不同程度的破坏。本次地震较2008 年3 月21 日于田MS7. 3 地震更靠近盆地,震害受场地条件影响明显,受灾范围更大。     

利用本体的WFS要素语义检索研究

为了实现基于多源WFS服务要素层次的语义检索,提出了一个要素本体的五元模型。在此框架下,研究了要素本体的自动构建方法,形式化定义了要素的空间关系,并扩展了逻辑关系以及空间关系的推理规则来实现要素层次的联合推理检索,并给出了联合规则推理的要素语义检索算法。实例证明,本文方法对多源WFS的语义查询具有实际的可行性,为多源WFS服务要素的语义检索提供了一个新的方法。     

重金属污染的菊芋茎秆沼气化性能及蓄积重金属的归趋

利用菊芋(Helianthus tuberosus)进行重金属污染土壤修复会产生大量秸秆废弃物,通过厌氧消化将其转化为沼气,是其资源化利用途径之一。为了评估该处置技术的环境风险,实验以重金属污染土壤种植的菊芋茎秆为对象开展厌氧消化研究,对其产气性能、重金属形态变化、可迁移能力及生物有效性进行评估。结果表明,菊芋秸秆中茎主要重金属(Cu,Zn,Pb,Cr,Cd)含量为5.69×10^-6,19.19×10^-6,0.23×10^-6,0.33×10^-6,0.50×10^-6,叶中的含量分别为9.11×10^-6,23.83×10^-6,0.57×10^-6,0.43×10^-6,0.48×10^-6相对与根与块茎较较高;菊芋秸秆厌氧发酵总产气量为206.58 ml·g^-1 TS,显示产气潜力良好;厌氧消化后,Cu,Pb和Cr的重金属可迁徙因子值低,相对比较稳定,迁移能力较弱。Cr和Cd的生物可利用度减小,其中Cr大幅度减小了41.54%,Cd减小了12.30%,说明厌氧消化能有效降低Cr和Cd的生物可利用度,减小对环境的危害。但Pb的生物有效性大幅度上升,应在沼渣管控环节关注。