Changes of marine productivity and sedimentary environment recorded by biogenic components in the Antarctica Ross Sea since the last deglaciation

Journal of Oceanology and Limnology - Changes in the marine productivity and sedimentary environment since the last deglaciation in the Ross Sea are presented in this paper. Opal has replaced...     

青海某矿浮选尾矿浸铜、金的研究I.铜的浸取

分别用常规浸取法和协同浸取法对青海某矿浮选尾矿进行浸铜的研究。使铜的浸取率由常规法的40％提高到协同浸取法的60—70％。这对于解决含结合氧化铜较高的金属尾矿的湿法冶金无疑是一个好方法。     

日潮特征海域回归潮平均高高潮位的计算方法

针对海岸线定义不适用于日潮特征海域的问题,分析了不同潮汐类型海域潮汐高潮位与月相和月赤纬间关系,提出并实现了日潮特征海域顾及日潮龄值的回归潮平均高高潮位计算。结果表明,在不规则日潮海域月赤纬极值与回归潮高高潮位表现出强相关性。海岸线定义明确为平均大潮高潮面或回归潮平均高高潮位与海岸的交接线更科学。     

垂线偏差反演重力异常中央区效应计算模型

为提高卫星测高反演重力场中央区效应的计算精度,以逆Vening-Meinesz公式为例,推导了包含4个网格的矩形中央区效应计算模型;基于"非奇异变换"思想,推导了中央区垂线偏差展开为泰勒级数式和二次多项式的非奇异变换法计算模型一和模型二。结果表明:矩形中央区积分法得到了与非奇异变换法模型一完全相同的中央区效应计算模型。设计了基于EGM2008模型数据的仿真计算,计算结果表明:该公式计算的重力异常中央区效应与将中央区视为圆域的传统方法算得的结果差值最大能够达到数个毫伽;与形式更为复杂的非奇异变换法算得的结果基本一致,说明在中央区效应计算中,使用矩形域中央区模型更为合理。     

溶剂萃取法分离锂同位素研究进展

锂同位素(6Li和7Li)在原子能工业中占据着重要的地位。在众多锂同位素的分离方法和体系中,溶剂萃取法是一种具有较高分离系数,并最有望实现无毒、高效分离的工业生产方法。阐述了溶剂萃取法分离锂同位素的原理,综述了醇类与酮类、烷基膦与膦酸脂类、冠醚类及其它溶剂萃取体系在锂同位素分离中的研究现状及趋势,并展望了溶剂萃取法在锂同位素分离和未来青海、西藏盐湖锂资源高值化利用中的潜在应用前景。     

黄淮海平原冬小麦最大可能蒸散的估算

作物最大可能蒸散考虑了作物及当地地表状况,为当地地表实际覆盖情况下实际蒸散的理论上限值,能客观分析作物对水分的需求程度和农业干旱状况。基于遥感（叶面积指数和地表反照率）数据和逐日气象数据,利用Penman-Monteith公式,计算黄淮海平原小麦种植区27个气象站冬小麦生育期2000-2015年逐日蒸散,提取得到冬小麦生育期逐日最大可能蒸散数据集,并分析其时空变化特征及成因。结果表明:与联合国粮农组织（FAO）单作物系数法计算的最大可能蒸散E_k对比,区域平均最大可能蒸散E_c的时间变化趋势与E_k一致,空间分布上E_c符合客观实际。黄淮海平原冬小麦全生育期、越冬期和返青-拔节期E_c均呈北低南高的分布特征,日平均值分别为1.99 mm,0.44 mm和2.75 mm;其余3个生育期（越冬前、抽穗期、乳熟-成熟期）在空间分布上差异不大,日平均值分别为1.23 mm,4.71 mm和3.74 mm。冬小麦不同生育期（含全生育期）E_c的空间分布主要受叶面积指数分布特征的影响,二者呈显著正相关关系。     

Induction of EROD activity in Paralichthys olivaceus by polychlorinated biphenyl CB-28

Abstract-The test organisms (Paralichthys olivaceus) were exposed to CB-28 with differentspiked concentrations. After 72 h, EROD activities in livers of the test organisms were measured. It wasfound that EROD activities significantly mounted up with the increase of spiked quantity. Therefore,there existed a dose-response relationship between EROD activities and specific pollutant concentrations.In the meantime, the optimal conditions for the analysis of EROD activity were discussed. The limita-tion of EROD activities as a monitoring parameter was also analyzed.     

Drip irrigation enhances shallow groundwater contribution to crop water consumption in an arid area

Shallow groundwater plays a key role in agro‐hydrological processes of arid areas. Groundwater often supplies a necessary part of the water requirement of crops and surrounding native vegetation, such as groundwater‐dependent ecosystems. However, the impact of water‐saving irrigation on cropland water balance, such as the contribution of shallow groundwater to field evapotranspiration, requires further investigation. Increased understanding of quantitative evaluation of field‐scale water productivity under different irrigation methods aids policy and decision‐making. In this study, high‐resolution water table depth and soil water content in field maize were monitored under conditions of flood irrigation (FI) and drip irrigation (DI), respectively. Groundwater evapotranspiration (ET_g) was estimated by the combination of the water table fluctuation method and an empirical groundwater–soil–atmosphere continuum model. The results indicate that daily ET_g at different growth stages varies under the two irrigation methods. Between two consecutive irrigation events of the FI site, daily ET_g rate increases from zero to greater than that of the DI site. Maize under DI steadily consumes more groundwater than FI, accounting for 16.4% and 14.5% of ET_a, respectively. Overall, FI recharges groundwater, whereas DI extracts water from shallow groundwater. The yield under DI increases compared with that under FI, with less ET_a (526 mm) compared with FI (578 mm), and irrigation water productivity improves from 3.51 kg m^?3 (FI) to 4.58 kg m^?3 (DI) through reducing deep drainage and soil evaporation by DI. These results highlight the critical role of irrigation method and groundwater on crop water consumption and productivity. This study provides important information to aid the development of agricultural irrigation schemes in arid areas with shallow groundwater.