N-nitrodimethlyamine in natural and drinking water of high cancer incidence regions of Guangdong,China

The Guangdong province of China contains the most clearly described high-incidence of hepatocellular carcinoma (HCC) and nasopharyngeal carcinoma (NPC) areas in the world. The geographical heterogeneity of cancer incidence in the region suggests that many carcinogenic risk factors might be present in the regional geochemical environment. This paper presents the concentrations of a wide range of known carcinogens in two high cancer incidence areas in Guangdong and compared them to a low cancer incidence area in the same province. N-Nitrosamines, NO₃⁻, NO₂⁻, and ammonium were detected in groundwater, surface water, and drinking-water. The concentrations of the 7 trace metal and metalloid elements As, Cd, Ni, Cu, Pb, Zn, and Hg were determined in surface soil samples and all water samples. The results show that, compared with the guidelines or limit values for drinking-water quality in the world, the high cancer incidence areas have hazardous high levels of N-nitrodimethlyamine (NDMA) in all kinds of water. Oppositely, the low cancer incidence area has a safe low level of NDMA in water bodies. The levels of NO₃⁻, NO₂⁻, and ammonium in water have the same character, although they have different expression between the two high-risk areas. The distribution of the 7 tested trace elements in surface soil has no significant correlation with cancer incidence. On the other hand, high concentrations of carcinogenic N-Nitrosamines in drinking-water and natural water bodies were identified for the first time in the high NPC and HCC incidence area.     

Modelling of geographic cancer risk factor disparities in US counties

The goal of this research is to create a theoretical framework for the identification of cancer risk factor disparities and address the recognition of geographic patterns in these factors. 34 secondary variables covering the entire US at the county level in 2010 were analyzed, both individually and grouped (theoretically and statistically), in relation to the mortality to incidence ratio (MIR) for all cancer sites. An a priori assessment and a principal components analysis (PCA) were used to group variables to test societal constructs. OLS and geographically weighted regressions (GWRs) were used to assess influence of both individual and grouped variables against the MIR. The theoretical grouping of variables showed little change in predictive capability of OLS models. In GWR model, there was marked improvement over the OLS. Maps produced using local R2 showed clear regional patterns of influence between the indicators and the MIR. Both the theoretical model and the justification for a spatial approach to cancer risk factor disparities were shown to be effective in this paper. The link between this suite of indicators and the health outcomes is clear, and supports the idea that a full representation of the SES landscape should be used to both predict health outcomes and to assess policy options for improving these outcomes. With the presence of definitive regional patterns and clear connections between the MIR and societal groupings, the findings from this research suggest a need to shift to a more comprehensive and spatial approach to cancer disparities research.     

高面板坝地震动非一致输入响应规律

在多点输入方法和等价黏弹性模型的基础上,采用半解析的波函数组合法实现了面板堆石坝在非一致输入下的动力计算。从频域散射角度对计算方法的合理性进行了验证。对比了非一致输入与一致输入下高面板堆石坝的动力响应,发现在采用基岩自由表面点的振动过程相同的对比标准下,非一致输入的整体动力响应较小;在面板坝防渗系统相对薄弱的止水结构附近,非一致输入的动拉应力最大值比一致输入的结果更大;非一致输入下大坝动力响应值的分布相比一致性输入呈现出中间小、周边大的特性。并基于波动理论进一步分析了不同种类地震波入射角度对高面板堆石坝动力响应的影响,揭示了P波、SV波和SH波入射下高面板堆石坝动力响应规律：随着入射角的增大,SH波入射时,高面板坝动力响应强度基本不变; SV波入射时,存在一个临界角,当入射角在临界角左右时高面板坝动力响应强度急剧增大和减小,之前基本不变,之后一直减小;P波入射时,存在一个特征角度,在入射角小于特征角度时高面板坝动力响应强度基本不变,大于特征角度时高面板坝动力响应强度减小。     

物元可拓模型的改进及其在膨胀土分类中的应用

指出物元可拓模型的关联函数是一个分段函数,不便于计算,指标间的互不相容性没有得到彻底解决,影响了物元分析法的应用范围。通过构造一种新的关联函数,改进了物元可拓模型,较好地解决了指标间的互不相容性问题,又便于计算,拓宽了物元分析法的应用范围。将改进的物元可拓模型应用于膨胀土的胀缩等级分类,其合理性和有效性得到了验证。     

Ground motion records for seismic performance assessment: To rotate or not to rotate?

The response of a non‐circular structure strongly depends on the orientation of the horizontal ground motion components vis‐à‐vis the structure's principal axes. At the same time, the structural response is also a function of accelerogram characteristics that give rise to considerable record‐to‐record variability even when the incident angle is neglected. Therefore, when the structural orientation relative to the fault geometry is unknown and we have limited resources for estimating the distribution of structural response given the seismic intensity, the question arises as to whether it is preferable to use (1) few records rotated to multiple orientations, (2) many records, each at a random incident angle, or (3) some combination of the two. To this purpose, we subjected several single‐degree‐of‐freedom systems and one plan‐asymmetric multi‐degree‐of‐freedom structure to a pulsive and a non‐pulsive set of ground motions using different combinations of record set size and incident angle rotations. In all cases, the natural record‐to‐record variability of the (unrotated) waveforms clearly outweighed the influence of the record orientation. In addition, the choice of an intensity measure that utilizes the geometric mean of spectral accelerations in both horizontal axes at one or more periods of vibration was found to further enhance this difference, essentially nullifying the already small effect of the incident angle. In all cases, spending any significant proportion of the limited number of dynamic analyses to incorporate the effect of incident angle was detrimental to the fidelity of the estimated performance.     

地震波斜入射下层状场地中地下综合管廊地震响应分析

利用黏弹性人工边界和等效地震荷载时域波动输入方法,结合土层和半空间的精确动力刚度矩阵,实现了地震波斜入射下层状场地地下综合管廊地震反应分析,建立了不同场地条件下地下综合管廊分析模型。计算结果表明:地震波倾斜入射情况下,综合管廊结构地震响应与垂直入射时具有显著差异,一般SV波以30°临界角附近入射时结构地震反应最为剧烈;地下综合管廊动应力集中主要分布在管廊角部、中柱上下端;成层土波速结构变化对地下综合管廊地震反应亦具有显著影响。总体上看:当穿越软夹层时管廊结构地震反应更为剧烈,且覆盖层越厚,管廊结构内力幅值越大。因此地下综合管廊结构抗震设计宜考虑地震波倾斜入射及场地土层性质的影响。     

地闪对崇明地震台地球物理观测的干扰

通过对比崇明地区地闪及崇明地震台地球物理观测资料,发现受地闪引起的电磁场变化的直接作用或对仪器元件的间接作用,地磁、地电、电磁扰动和水位观测干扰比例较高,干扰幅度与地闪距离及形成的电流强度有关。具体干扰形态如下:①对电磁扰动干扰表现为单向突跳和测值的整体抬升;②对地磁测项干扰表现为正负方向的单点突跳;③对大地电场干扰表现为大幅震荡;④对水位观测干扰表现为大幅突跳。     

Spatial seismic modeling of base‐isolated buildings pounding against moat walls: effects of ground motion directionality and mass eccentricity

Structural impact between adjacent buildings may induce local and, in some extreme cases, severe damage, especially in the case of seismically isolated buildings. This study parametrically investigates in the three‐dimensional domain the effect of pounding on the peak response of base‐isolated buildings, which are simulated as nonlinear three‐dimensional multi‐degree‐of‐freedom systems. Firstly, it is shown that considering unidirectional, instead of bidirectional, excitations may lead to underestimation of the base drift demands. Subsequently, the peak responses of seismically isolated buildings utilizing lead rubber bearings are studied while varying important parameters, such as the incidence angle of seismic excitations, the available seismic clearance, and mass eccentricities, under the action of bidirectional horizontal excitations. A large number of numerical simulations are performed using a specially developed software that implements an efficient approach to model impacts, taking into account arbitrary locations of contact points. It is found that the peak interstory drift ratio is significantly influenced by the directionality of the ground motion. Therefore, the seismic performance of structures should ideally be assessed examining the peak structural response while bidirectional ground motions are imposed at various incident angles. Furthermore, it is also observed that the interstory drift ratios increase while decreasing the available gap size, up to a certain value. Finally, the parametric analyses indicate that the effects of impact are more severe for structures with mass eccentricities, and in which case, the estimation of the critical incidence angle becomes more laborious. Copyright © 2016 John Wiley & Sons, Ltd.     

娘子关泉域降水补给的时滞研究

针对娘子关泉域降水补给的时滞问题展开研究,根据泉域水文地质条件的灰色系统特征,提出了带有时滞的灰色关联分析模型,并运用该模型对泉域不同区域的降水量与泉水流量进行了时滞分析,结果表明,娘子关泉域不同区域的降水对娘子关泉的补给时滞存在差异,位于中间主流带的阳泉市、平定、盂县、昔阳与和顺的降水时滞为2年;位于西南、西北径流区边缘的寿阳和左权的降水时滞为4年。      

临南洼陷沙三段孔隙度控制因素分析与定量模型

利用物性数据分析、铸体薄片鉴定、扫描电镜观察、图像分析技术等手段,探讨了临南洼陷沙三段砂岩储层孔隙度控制因素,并运用灰色关联等研究方法量化各因素的影响程度,最终建立储层孔隙度综合预测模型。结果表明,控制临南洼陷沙三段砂岩储层孔隙度的因素包括与沉积相关的粒度因素和分选因素,以及与成岩相关的压实因素、胶结因素和溶蚀因素。在限定压实条件下,孔隙随埋深的变化和岩石粒度、分选系数具相关性;粒度较粗的储集层物性相对较好,且分选性对原始物性的影响要大于粒级的影响;碳酸盐岩胶结物质体积分数大于5%时,孔隙度与碳酸盐岩体积分数呈负相关;以长石颗粒溶蚀为主的溶蚀作用具有明显的增孔效应;随着黏土矿物含量增高,孔隙度逐渐降低。运用灰色关联法量化各项地质参数对储层孔隙度的影响,进而在设定现今储层孔隙度为正常埋藏压实保存孔隙度与其他成岩作用对孔隙度贡献的叠加的前提下,建立了孔隙度综合预测的数学模型。经17组数据的验证,该预测方法的准确率可达90.5%。