元素俘获能谱测井标准谱测量与模拟(英文)

为了解决目前元素俘获能谱测井解释中,根据原始测量谱难以准确获得各个元素产额的困难,本文建立了一套先进的测量元素俘获伽马能谱实验方法,首次获得了硅、钙和铁等10种元素的标准俘获伽马能谱;并利用蒙托卡罗方法在同样条件下模拟得到了上述10种元素的标准模拟俘获伽马能谱。将这两种方式获得的元素标准俘获伽马能谱与国际原子能机构核数据中心数据进行对比分析,从中确定了可用于实际元素俘获能谱测井解谱计算的硅、钙和铁等10种元素的俘获伽马能谱。这一结果有效解决了元素俘获能谱测井资料处理过程中由原始测量谱到各元素产额转换过程中的关键技术难点,可有效提高元素产额的计算精度。     

Heterogeneous Nucleophilic Transformation of Metolachlor by Bisulfide on Alumina Surface

The present research elucidates the accelerating effect of alumina minerals on metolachlor transformation using sulfur nucleophiles and also determines the metolachlor transformation mechanisms in the heterogeneous reaction systems. Metolachlor transformation was first systematically investigated under different conditions. Then, the Fourier transform infrared (FTIR) spectra were used to characterize the changes in the surface bonds of the aluminas. The transformation products were qualitatively identified using LC/MS. The results showed that bisulfide can produce efficient metolachlor transformation rates, and the presence of the aluminas can further accelerate the transformation by achieving complete transformation in <21 days. In addition, a higher pH and higher bisulfide concentration are more favorable for metolachlor transformation. When normalized to the surface area, the metolachlor transformation rates were found to follow the order of α‐Al₂O₃>γ‐AlOOH>γ‐Al₂O₃ in the presence of different aluminas. FTIR results indicated that the enhancement of metolachlor transformation rates by bisulfide with aluminas can be attributed to the surface active nucleophiles on alumina surfaces formed through Al? S and Al? O bonds. The substitution of chlorine on the metolachlor followed the S_N2 mechanism by bisulfide with accelerated rate through mediating the heterogeneous reactions with aluminas.     

甘肃河西地区沙漠化遥感监测评估

 河西走廊位于我国西北干旱半干旱区,由于自然环境的变化和人为因素的影响,生态环境脆弱,沙漠化严重。随着遥感和GIS的发展,为沙漠化研究提供了有效的途径。利用2002和2008年6～8月的MODIS数据（空间分辨率为1 km）,采用改进型土壤调节植被指数（MSAVI）、地表反照率（ALBEDO）、陆地表面温度（LST）、植被覆盖度（FAVI）和温度植被旱情指数（TVDI）作为沙漠化程度的指标,对河西地区沙漠化特征进行了研究。结果表明：河西地区荒漠化土地面积较大,占总面积的50%以上。2008年的荒漠化土地面积比2002年减少了6 431.64 km²,非荒漠化土地和轻度荒漠化土地面积增加,分别增加了2.55%和0.26%;中度、重度和极重度荒漠化土地减小,分别减小了1.40%、1.09%和0.31%。荒漠化的逆转速度大于发展速度,呈现整体逆转,局部发展的趋势。研究区荒漠化土地以轻度荒漠化为主,2002年和2008年分别占23.64%和23.90%;其次为中度,分别为18.47%和17.07%;重度所占比例分别为12.71%和11.62%;极重度所占比例很小,不到1%。降雨和风速对沙漠化的逆转起主要作用,2008年的降水比2002年多,风速小。     

Geographical Detectors‐Based Health Risk Assessment and its Application in the Neural Tube Defects Study of the Heshun Region,China

Physical environment, man‐made pollution, nutrition and their mutual interactions can be major causes of human diseases. These disease determinants have distinct spatial distributions across geographical units, so that their adequate study involves the investigation of the associated geographical strata. We propose four geographical detectors based on spatial variation analysis of the geographical strata to assess the environmental risks of health: the risk detector indicates where the risk areas are; the factor detector identifies factors that are responsible for the risk; the ecological detector discloses relative importance between the factors; and the interaction detector reveals whether the risk factors interact or lead to disease independently. In a real‐world study, the primary physical environment (watershed, lithozone and soil) was found to strongly control the neural tube defects (NTD) occurrences in the Heshun region (China). Basic nutrition (food) was found to be more important than man‐made pollution (chemical fertilizer) in the control of the spatial NTD pattern. Ancient materials released from geological faults and subsequently spread along slopes dramatically increase the NTD risk. These findings constitute valuable input to disease intervention strategies in the region of interest.     

Integrating general principles into mixed-integer programming to optimize schematic network maps

ABSTRACT

Schematic maps are popular for the representation of transport networks. Many automated methods have been developed to generate such maps. In these methods, optimization techniques work with various sets of constraints. Most of these constraints govern geometric properties of individual features. A few constraints address relationships among features, but none explicitly deal with the main structure of an entire network. We believe that preservation of main structure is the most important and preservation of relative relations is helpful. This is because human perception follows a global-to-local process. These constraints have recently been formed into four general principles, with two for global structure and two for relativity of features. This study develops an automated method by integrating these principles into the mixed-integer programming (MIP) framework. Experimental evaluations have been conducted with two sets of real-world transit networks. In comparison to the existing method, the proposed method has smaller fractal dimensions, better computational performance and higher scores in terms of clarity, recognition of major lines, visual simplicity and satisfaction. Therefore, it is concluded that the proposed method can generate schematic maps with improved clarity and aesthetics. The idea in this study is also helpful for the design of other visual representations.     

Antarctica Sea-ice Oscillation and Its Possible Impact on Monsoon of South Sea

Antarctic sea-ice oscillation index with a seesaw pattern is defined using NCEP/NCAR reanalysis girds data of monthly Antarctica sea-ice concentration from 1979 to 2002. The relationships between the index of winter and the summer precipitations in China as well as the onset date of the summer East Asia monsoon are presented. The study result shows that the grids of correlation coefficients passed 5% confidence level between Antarctic sea-ice oscillation index and Antarctic sea-ice concentration are more than 1/3 of all grids of Antarctica sea-ice, that means the index can represent 1/3 sea-ice area. The winter index has a significant correlation with abnormal summer (June-August) precipitation in China. The area of positive correlation lies in the Yangtze River basin and its south, and that of negative correlation lies mainly in the north of Yangtze River basin. While the winter index is positive (negative), the onset date of South China Sea monsoon is earlier (later), with a probability of 79% (80%). Consequently, a conceptual model is given in term of discussing the possible process between the winter Antarctic sea ice and the monsoon precipitation in China.     

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Transmutation of ancient settlements and environmental changes between 6000–2000 aBP in the Chaohu Lake Basin,East China

Based on the temporal-spatial distribution features of ancient settlement sites from the middle and late Neolithic Age to the Han dynasty in the Chaohu Lake Basin of Anhui Province, East China, using the methods of GIS combined with the reconstructed paleoenvironment by the records of lake sediment since Holocene, the transmutation of ancient settlements with response to environmental changes in this area has been discussed. Studies show that the main feature of transmutation of ancient settlements from the middle and late Neolithic Age to the Han Dynasty was that the distribution of settlements in this area changed from high altitudes to low ones and kept approaching the Chaohu Lake with the passage of time. These could be the response to the climate change from warm-moist to a relatively warm-dry condition during the middle Holocene, leading to the lake level fluctuations. The large area of exposed land provided enough space for human activities. These indicate that the above changes in geomorphologic evolution and hydrology influenced by climate conditions affected the transmutation of ancient settlements greatly. The distribution pattern of settlement sites was that the number of sites in the west was more than in the east. This pattern may be related to the geomorphologic conditions such as frequent channel shifting of the Yangtze River as well as flood disasters during the Holocene optimum. Therefore, climate change was the inducement of the transmutation of ancient settlements in the Chaohu Lake Basin, which exerted great influence on the distribution, expansion and development of the ancient settlements.     

地震属性分析在高分辨率活断层地震勘探中的应用

通过分析影响地震属性的岩石物理特性及其在地震响应上的特征,获得地震波传播过程中地震振幅、层速度与裂缝层密度、泊松比、纵横波速度、孔隙度、压力的关系。同时,结合地震属性的分析技术,利用地震正演模拟的方法提高地震勘探数据解释结果精确度和可信度,为高分辨率的活断层地震勘探研究提供更为可靠的方法手段,提高了地震数据的处理解释精度。     

1002号台风对四川盆地大暴雨的影响分析

利用逐日NCEP再分析常规观测资料、逐小时自动站资料和卫星云图资料,对2010年7月14—18日发生在四川盆地的大暴雨天气过程进行诊断分析,重点探讨了台风活动对大尺度环流背景、西南低涡形成与维持、水汽及能量输送的作用。结果表明:(1) 本次暴雨是在副热带高压、台风、西南低涡等多个不同尺度系统相互作用下发生的;(2) 台风环流东侧偏南气流和副高西侧偏南气流长时间的融合贯通,一方面有利于“鞍”型场大尺度环流背景稳定和低层西南涡的发展及维持;另一方面两支气流叠加构成输送带,将低纬大量水汽和热量向暴雨区上空输送,有利于暴雨区上空水汽的积聚及形成高能不稳定区;冷暖空气交绥于暴雨区,促使不稳定能量释放,形成大暴雨天气。