A THREE-DIMENSIONAL ELASTIC NESTED-GRID MESO-(β-γ)SCALE ATMOSPHERIC MODEL——PARTI:MODEL DESCRIPTION

A three-dimensional elastic nonhydrostatic mesoscale(β-γ)model with nested-grid is presented.It uses a set of fullequations in terrain-following coordinates as its basic dynamic frame,which is solved with a time-splitting algorithmfor acoustic and gravity waves.The model physical parameterization includes a K-theory subgrid eddy mixing for cloudand free atmosphere,a bulk planetary boundary layer parameterization,and three types of sofisticated cloudmicrophysics schemes with double-parameters for hail-bearing clouds,warm clouds and snowing clouds respectively.The model is designed to be used flexibly for simulations of a variety of meso-and small-scale atmospheric processes,and can be improved as a regional and local operational NWP system in future.     

黄金的成色

黄金的成色并不是一成不变的，它成色的高低是与成矿温度、成矿阶段、深度、时代、变质程度、水溶液及风化作用等有一定关系，我们从这些关系中可以寻找到我们找矿的捷径和依据。     

The impact of wave loads and pore-water pressure generation on initiation of sediment transport

The build-up of pore-water pressure by waves can lead to sediment liquefaction and subsequent transport by traction currents. This process was investigated by measuring pore-water pressures both in a field experiment and laboratory wave tank tests. Liquefaction was observed in the wave tank tests. The results suggest that sand is less susceptible than silts to wave-induced liquefaction because of the tendency to partially dissipate pore-water pressures. However, previous studies have determined that pore-water pressures must approach liquefaction before current velocities necessary to initiate transport are reduced. Once liquefaction has occurred more sediment can be transported.     

Refugee flow or brain-drain? The humanitarian policy and post-Tiananmen mainland Chinese immigration to Canada

"The humanitarian policy that the Canadian government implemented in response to the 1989 Tiananmen Square crackdown changed a migration system primarily based on personal networks into a brain drain. Post-Tiananmen mainland Chinese immigrants (MCIs) were better educated than those arriving in Canada previously. Among the post-Tiananmen MCIs, those who landed under the policy were better educated than those landing in other categories. The analysis suggests that post-Tiananmen MCIs represented a brain-drain rather than a refugee flow, that the humanitarian policy implicitly contained ideological and human capital concerns in addition to humanitarian concerns, and that Canada benefited from the policy by obtaining human capital as well as satisfying its humanitarian obligations and ideological aspirations."     

扬子地台钾镁煌斑岩 Nd、Sr、Pb 同位素特征

扬子地台周缘钾镁煌斑岩 Nd、Sr同位素特征介于南非Ⅰ、Ⅱ型金伯利岩和西澳与北美钾镁煌斑岩两种变化趋势之间，不同岩区间同位素组成差异反映地台周边构造性质不同，Pb同位素特征表明晚太古代地幔岩石圈具U亏损特征。     

草簇状石墨烯片限域Pd纳米粒子及其催化应用(英文)

通过氨基离子液体改性石墨烯,并将其固载于堇青石表面,作为负载型Pd催化剂的载体.所制备的Pd催化剂经加氢老化后,表面石墨烯呈草簇状结构,将Pd纳米粒子限域于片层内,有效防止了Pd的流失和团聚.在重要的工业反应对羧基苯甲醛(4-CBA)加氢中,此结构催化剂与传统的钯碳催化剂相比,表现出很好的稳定性     

颗粒分析用量筒的规格标准和计量标定

文章讨论了国内外用于密度计法颗粒分析用量筒的计量标准的规定，提出了相应的建议和标定方法。     

Typical basin-fill sequences and basin migration in Yanshan, North China--Response to Mesozoic tectonic transition

Basin-fill sequences of Mesozoic typical basins in the Yanshan area, North China may be divided into four phases, reflecting lithosphere tectonic evolution from flexure (T3), flexure with weak rifting (J1+2), tectonic transition (J3), and rifting (K). Except the first phase, the other three phases all start with lava and volcaniclastic rocks, and end with thick coarse clastic rocks and/or conglomerates, showing cyclic basin development rather than simple cyclic rift mechanism and disciplinary basin-stress change from extension to compression in each phase. Prototype basin analysis, based on basin-fill sequences, paleocurrent distribution and depositional systems, shows that single basin-strike and structural-line direction controlling basin development had evidently changed from east-west to northeast in Late Jurassic in the Yanshan area, although basin group still occurred in east-west zonal distribution. Till Early Cretaceous, main structural-line strike controlling basins just turned to northeast by north in the studied area.     

山东省气候变化及其对冬小麦生产潜力的影响

利用全省 2 7个台站 1 96 1～ 1 998年的温度、降水、日照等基本气象要素资料 ,对山东省气候变化特点进行了分析 ,并对冬小麦生产潜力进行了计算、分析。结果表明 ,山东省年、季平均气温呈波动性增暖趋势 ,降水量呈减少趋势。气候变暖有利于生产潜力的提高 ,冬小麦气候生产潜力总的变化趋势是波动性的上升 ,但较光温生产潜力倾向率小 ,反映了小麦生育期内光、温、水的综合影响。