Source and distribution of mercury in natural gas of major petroliferous basins in China

Based on the analysis of the natural gas samples of 146 wells from four major petroliferous basins of China, the source and distribution of mercury in natural gas in major petroliferous basins of China were identified. Studies have shown that the mercury concentration of natural gas in petroliferous basins of China varies widely, ranging from 0.01 to 4050 μg/m~3. The gas well with the highest mercury concentration is in the Xushen gas field in the Songliao Basin. The mercury concentration in the craton basin is relatively low, and the secondary gas reservoir in the Tarim Basin has the lowest mercury concentration. In the rift basin, due to the presence of deep faults which cut the basement and mixing effects of deep fluids, the mercury concentration in natural gas may be abnormally high, e.g. the Xushen gas field in the Songliao Basin. In relatively stable basins where deep and large faults do not develop, mercury is primarily of organic origin. In rift basins where deep fluids are mixed with gas reservoirs,mercury in natural gas may mainly come from the deep fluids and is characterized by abnormally high mercury concentration and R/Ra values.     

Wind tunnel tests of the dynamic processes that control wind erosion of a sand bed

Aeolian sand transport is a complicated process that is affected by many factors (e.g. wind velocity, sand particle size, surface microtopography). Under different experimental conditions, erosion processes will therefore produce different results. In this study, we conducted a series of wind tunnel experiments across a range of wind velocities capable of entraining sand particles (8.0, 10.0, 12.0, and 14.0 m s^-1) to study the dynamic changes of the shear velocity, aerodynamic roughness length, and sand transport. We found that the shear velocity and aerodynamic roughness length are not constant; rather, they change dynamically over time, and the rules that describe their changes depend on the free-stream air velocity. For wind tunnel experiments without feeding sand into the airflow, the sand bed elevation decreases with increasing erosion time, and this change significantly affected the values of shear velocity and aerodynamic roughness length. A Gaussian distribution function described the relationships between the sand transport rate (q_T) and the duration of wind erosion (T). It is therefore necessary for modelers to consider both deflation of the bed and the time scale used when calculating sand transport or erosion rates. © 2018 John Wiley & Sons, Ltd.     

结合纹理特征的SVM海冰分类方法研究

海冰分类是遥感监测领域中的重要应用之一,海冰分类的准确性对于评估海冰冰情、保证航海安全和开辟北极航道具有重要的意义。针对海冰分类问题,本文选用Sentinel-1遥感数据,结合纹理特征分析,提出了一种改进的SAR海冰分类方法。该方法选用灰度共生矩阵提取特征值,通过实验得到适宜用于海冰分类的多特征组合,在此基础上利用支持向量机开展SAR海冰类型的分类研究。实验结果表明,该方法可以实现对海冰SAR图像中一年冰、多年冰和海水3种类型识别,与传统的海冰分类方法神经网络和最大似然法相比较,使用SVM分类方法,结合纹理特征开展海冰类型监测是可行的,同时也表明多特征组合有利于提高SAR图像的分类精度,从而验证了本方法的有效性,为海冰分类提供了一种新思路。     

综合伪距相位观测的实时电离层延迟格网改正算法研究

针对北斗广域差分系统实时电离层延迟格网改正信息是基于伪距观测计算,而相位观测值具有更高的观测精度,提出伪距数据结合相位历元间差分数据综合解算电离层延迟的算法。基于陆态网GPS实测数据对该伪距相位综合算法进行实验验证,结果表明,综合伪距相位算法相比单纯伪距法可以获得平滑、稳定、精度更高的站星斜路径方向电离层延迟值。在此基础上,全天所有实时电离层延迟格网的内符合精度平均提高30.2%,外符合精度平均提高27.8%。     

日极差法在识别地下水位异常动态中的应用

针对新疆呼图壁２１号泉地下水位动态特征,提出新的识别异常方法－日极差法,在分析天山中段５段地震和新疆境内大于６．０级地震前后２１号泉地下水位动态异常变化时,发现用日极差法消除水动态随机变化,突出,识别异常,效果显著,震例验证结果及地震预报效能评价证明：日极差法具有操作性能强,简便,快速,有效的特点。     

乌鲁木齐10号泉水汞短临前兆特征探讨

从１０号泉地下水汞的地球化学特性入手,结合近５年来１０次震例,分析并初步总结了地下水水泵的短临前兆特征,水泵的短临异常的出现往往是突发性的;汞异常形态特征基本上具有一定重复性的正异常,仅有个别地震时出现负异常。映震范围;对５级以下地震,水汞异常范围约在６００ｋｍ以内,对５级地上地震,水汞异常范围约在３５０ｋｍ以内;对个别７级以上地震可能映震范围接近１０００ｋｍ。汞异常时间与发震;在前兆近场,往往在     

安徽中西部地区地震活动特征的对比分析

针对安徽中西部地区目前存在的多项测震学指标异常,重点对比分析了该区域1970年以来三个活动时期的地震活动时空特征.认为本活跃期期间(1990年以来)地震活动特征总体上与第四个活动期期间(1970年～1979年)比较类似,但活动水平要低,时间上还将持续1年至1年半左右.     

渤海莱州湾红鳍东方鲀(Takifugu rubripes)×假睛东方鲀(Takifugu pseudommus)天然杂交种一例

记述了１９９８年５月莱州湾中采得的东方（Ｔａｋｉｆｕｇｕ）标本中的２尾个体,其形态特征介于红鳍东方（Ｔａｋｉｆｕｇｕｒｕｂｒｉｐｅｓ）和假睛东方（Ｔａｋｉｆｕｇｕｐｓｅｕｄｏｍｍｕｓ）之间,经比较分析认定其为该两近缘种的天然杂交种     

塞拉利昂近海经济虾类数量与分布初步研究

根据塞拉利昂近海１６条生产船１年（ａ）生产日志资料（１９９５－０７～１９９６－０６）,分析了２种经济虾类［红对虾（Ｐｅｎａｅｕｓｎｏｔｉａｌｉｓ）、大西洋仿对虾（Ｐａｒａｐｅｎａｅｏｐｓｉｓａｔｌａｎｔｉｃａ）］的产量分布,指出红对虾主要分布于以２区,４４区,８５区为中心的３个渔场,主要虾汛时间为６～８月,大西洋仿对虾主要分布于８４区,９６区,９７区,主要虾汛时间为１１月。同时,还对２种虾类的月平均单船产量进行了比较分析。     

现代计算机印前制版技术在遥感图像印制中的应用研究——以《长江经济带可持续发展地图集》为例

利用现代计算机印前制版技术开展遥感图像印制中的应用研究。通过Barco系统软件功能很好反映遥感图像的信息特征.