青海地区地震磁扰动异常特征研究

以青海地区8个测点磁通门秒采样观测数据为研究对象,利用地磁垂直强度极化法结合该区域中强地震背景进行分析。基于极化背景场变化特征提取震磁异常在研究区实际应用中取得以下认识:多台站同步极化高值异常对于2个月以内青海地区5级左右及以上地震有一定映震能力,且异常具有一定信度;测点密度均匀分布情况下,震中位置基本位于极化高值区域。     

高频燃烧-红外吸收光谱法测定钼矿石和镍矿石中的高含量硫

高频燃烧-红外吸收法用于分析矿石中低含量硫的测定结果较为准确,但对于高含量的硫,分析结果的准确度不高。本文采用高频燃烧-红外碳硫分析仪测定钼矿石和镍矿石中的高含量硫,选择纯铁屑和钨粒作助熔剂,高温燃烧分解样品,通过实验优化了样品称样量、助熔剂用量、仪器分析时间等测定条件。用国家标准物质进行验证,方法精密度(RSD,n=9)小于1%,加标回收率为96.0%～101.9%;与传统的硫酸钡重量法进行比对试验,测定值的相对误差小于2%。针对不同的矿石样品,研究了实际样品与标准物质的基体匹配问题,消除了基体效应的影响,对于钼矿石和镍矿石样品中含量在1%～35%范围内的硫,均能够准确测定,解决了钼矿石和镍矿石中高含量硫的快速、准确测定问题。     

Polychlorinated biphenyls residues in surface sediments of the eutrophic Chaohu Lake (China): characteristics, risk, and correlation with trophic status

Twenty-eight polychlorinated biphenyls (PCB) congeners were measured in surface sediments from Chaohu Lake to assess their characteristics, potential risk, and the correlation with lake trophic status. PCB levels ranged from 11.074 to 42.712 ng g^?1 dry weight (d.w.) in the western lake and 2.017 to 20.189 ng g^?1 d.w. in the eastern lake. The highest concentrations were found at the sites near the inlets of western lake tributary rivers where big cities and industrial centers are located. Congeners concentrations showed decreasing order of tetra-CB > tri-CB > deca-CB (PCB-209 detected) > penta-CB > hexa-CB > di-CB > hepta-CB > Octa-CB. It indicated that light and heavy Aroclor mixtures were simultaneously used surrounding the lake basin. PCB levels in the western lake are potentially dangerous to humans and the local fauna. There was a significant positive relationship between tetra-CB (one abundant PCB congener) concentration distribution and sediment grain size in the 16–64 μm fraction, whereas a negative correlation was found in the 4–8 μm fraction. Furthermore, PCB distributions were positively correlated with the total organic carbon of sediments and lake trophic status, especially in the more seriously polluted western lake zone. However, the correlation completely disappeared in eastern lake zone. It suggested that PCB contamination might be attributed to industrial wastewaters and domestic sewages from western lake basin, reaching the lake through rivers, rains and floods.     

Structure equation model-based approach for determining lake nutrient standards in Yungui Plateau ecoregion and Eastern Plain ecoregion lakes,China

Predictive nutrient criteria method, combined with expert elicitation and structural equation model (SEM), was proposed in this study for establishing lake nutrient standard in Chinese lakes (Yungui Plateau ecoregion and Eastern Plain ecoregion). Expert elicitation was involved to quantify the probability of attainment of the designated-use (drinking water source) based on monitoring data. The experts scoring results were introduced to SEM to assess predictive relationships between candidate standard variables and the designated-use attainment. In Yungui ecoregion, the standardized effects of chlorophyll-a (Chl-a), chemical oxygen demand and total phosphorus (TP) on designated-use attainment were ?0.41, ?0.14, and ?0.43, respectively. These result demonstrated that the two most predictive indicators for designated-use attainment were TP and Chl-a. In Eastern ecoregion, the standardized effects of TP, total nitrogen (TN), dissolved oxygen and water temperature (T) on designated-use attainment were 0.77, ?0.12, 0.13 and ?0.02, respectively. The most predictive indicator was TP. The model was further used for estimating the designated-use attainment associated with various levels of candidate standards. TP, TN, Chl-a and Secchi depth (SD) were selected as standard indicators in Yungui ecoregion. TP, TN, and Chl-a were selected in Eastern ecoregion. In order to achieve the 85 % designated-use attainment, standard values of TP, TN, Chl-a and SD in Yungui ecoregion would be 0.02 mg/L, 0.2 mg/L, 1.4 μg/L, and 0.581 m; and standards of TP, TN, and Chl-a in Eastern ecoregion would be 0.039 mg/L, 0.95 mg/L, and 1.75 μg/L, respectively. Finally, the differences between standards in these two ecoregions were also analyzed.     

Simulation on forecast and control for groundwater contamination of hazardous waste landfill

The groundwater flow and solute transport models were established by Visual Modflow, which was used to forecast the transport process of Cr⁶⁺ in groundwater and simulate the effects of three control measures of contaminants transport after percolation solution leakage happened in the impermeable layer of the landfill. The results showed that the contamination plume of Cr⁶⁺ would reach the pool’s boundary in 10 years, and the distance of contamination transport was 1,450 m. However, the contamination plume will not be obviously expanded between 10 and 20 years. While the ground was covered by hardened concrete, the contamination plume would not reach the pool’s boundary in 20 years. When the leakage-proof barrier was set in the bottom of an unconfined aquifer, the concentration of Cr⁶⁺ was higher than that of the leakage-proof barrier unset, but the result was opposite when setting the leakage-proof barrier in the bottom of confined aquifer. The range of the contamination plume was effectively controlled by setting drainage ditches in which water discharge was 2,298.05 m³ d^?1, which produced monitoring wells which are not contaminated in 20 years. In sum, combining ground hardening with drainage ditches could produce the best effect in controlling contaminants diffusion, and meanwhile, the drainage ditches daily discharge was reduced to 1,710.19 m³ d^?1.     

The role of coupling and embeddedness in risk evolution: rethinking the snow event in early 2008, China

New forms of hazards generated by extreme weather pose new challenges to emergency management. The purpose of this paper is to identify a typical evolution dynamics by analyzing coupling and embeddedness in risk evolution via critical infrastructure system under extreme weather. Evidence from the snow event in early 2008, China, is used to draw the viewpoint and support the argument. The paper identifies the dynamics that how a natural hazard of extreme weather evolves into a social crisis and how coupling and embeddedness contribute to the evolution. This paper makes it evident that the impact of natural hazard to a society can obtain amplification through coupling and embeddedness. Therefore, new challenges in risk evolution should become a highlighted direction for further research. This paper sheds light on a new profile for social impact research of natural hazard and provides new insights into systems thinking on emergency management.     

瞬变电磁测量在吐哈盆地十红滩铀矿区勘查中的应用效果

将瞬变电磁法应用于吐哈盆地十红滩地区铀矿勘查,采用分离回线装置方式进行测量,划分了找矿目的层的结构、埋深、厚度及空间展布特征,基本查明了矿区基底隐伏断裂及褶皱构造位置,研究认为解释出的构造与砂岩型铀矿成矿关系密切,对该地区铀矿找矿工作具有一定的指导作用。通过后期钻孔验证,取得了良好的地质效果。     

基于中国地质调查信息网格的“立体一张图”服务构建与应用

目前,中国地质调查信息网格通过"地质矿产一张图"实现了地表范围内地质空间信息的高度集成与共享,但是地下三维地质空间信息的集成共享状况对现有的数据发布机制、服务效率与共享能力提出了更高的要求。本文基于中国地质调查信息网格,在构建"地质矿产立体一张图"服务框架的基础上,从三维空间数据的组织管理着手,重点研究了多结点下的数据发布与发现机制、三维可视化与场景服务、多样化用户界面表达方式,实现了网格环境下三维地质空间信息的实时快速绘制和高效交互处理;并针对矿体三维模型和地质三维模型等,提供了信息集成与应用服务,取得了良好效果。     

基于生成对抗网络的建筑物损毁检测EI北大核心CSCD

建筑物作为自然灾害中最受影响的承灾体之一,其损毁信息的准确提取对灾后应急救援具有十分重要的意义。本文借鉴多模态的思想,提出了一种自动检测损毁建筑物的recursive-generative adversarial networks(RS-GAN)方法,将损毁建筑物检测分为灾前建筑物识别和灾后损毁建筑物检测两个任务,且分别在两个GAN分支中完成。RS-GAN加入联合损失函数将两个GAN分支进行连接,充分利用两个任务之间的潜在互利性提升检测效果。RS-GAN利用第1条GAN分支识别建筑物灾前形状与位置,并将识别结果作为第2条GAN分支的输入进行损毁建筑物检测任务,从而使检测结果具有更清晰的轮廓。该方法为端到端模型,在不需要过多的人工干预情形下,实现了损毁建筑物的自动检测。为了验证RS-GAN模型的效果,在圣罗莎和密苏里两个数据集上进行了测试。试验结果表明,RS-GAN方法拥有更好的检测性能,在圣罗莎数据集上的总体精度和平均精度分别达到了0.90和0.86。     

基于漂流浮标观测分析日本福岛以东表层海洋物质的散播轨迹

认识海洋中的物质如何散播对于理解海洋环境变化和人类活动污染在海洋中的扩散过程具有非常重要的意义。利用历史海表漂流浮标观测数据,对日本福岛以东海域的表层物质散播轨迹进行了拉格朗日示踪分析和观测模拟试验研究。结果发现,福岛以东海域海表浮标的散播路径主要分为东、南两支,其中速度较快的东支为主要通道,沿黑潮延伸体汇入北太平洋流,最短用时大约22个月即可到达北美西海岸;南支则沿黑潮延伸体以南的大范围南向流向西南方向运移,速度较慢且明显受涡旋活动影响,最快大约5个月即可到达吕宋海峡和中国台湾以东海域,进而进入南海和东海等中国近海海域。通过开展观测模拟试验,发现海表浮标散播的概率密度分布呈现以福岛附近海域为核心、向西南和正东方向递减扩展的形态,其中,到达中国近海的浮标主要通过吕宋海峡进入。文章详细讨论了研究结果的局限性、不足之处,以及因基于大量现场观测而具备的重要参考价值。