与飞机观测资料对比评估WRF微物理方案集合的模拟能力

使用WRF模式中的Morrison,WSM6,SBM,P3四种微物理方案的集合,模拟中尺度对流系统降水过程.研究发现不同的微物理方案模拟的对流云区液态含水量,冰水含量的垂直分布各不相同,而模拟的层状云区液态含水量,冰水含量的垂直分布结果相似.总的来说与其他方案相比,Morrison方案和集合平均的结果最接近观测值.我们...     

On the nature,formation and diversity of particulate coherent structures in microgravity conditions and their relevance to materials science and problems of astrophysical interest

Different phenomena related to the spontaneous accumulation of solid particles dispersed in a fluid medium in microgravity conditions are discussed, with an emphasis on recent discoveries and potential links with the general field of astrophysical fluid-dynamics on the one hand, and with terrestrial applications in the field of materials science on the other hand. With special attention to the typical physical forces at play in such an environment, namely, surface-tension gradients, oscillatory residual gravity components, inertial disturbances and forces of an electrostatic nature, specific experimental and numerical examples are presented to provide inputs for an increased understanding of the underlying cause-and-effect relationships. Studying these systems can be seen as a matter of understanding how macroscopic scenarios arise from the cooperative behaviour of sub-parts or competing mechanisms (nonlinearities and interdependencies on various spatial and temporal scales). Through a critical assessment of the properties displayed by the resulting structures (which appear in the form of one-dimensional circuits formed by aligned particles, planar accumulation surfaces, three-dimensional compact structures resembling “quadrics”, micro-crystallites or fractal aggregates), we discuss a possible classification of the related particle attractors in the space of parameters according to the prevailing effect.     

Z-I关系最优化处理法改进研究

通过对在雷达—雨量计联合估测区域降水量研究中广泛使用的Z-I关系最优化处理法进行深入分析发现,使用该处理方法存在两个问题,一个是其判别函数的推理基础薄弱,需对该判别函数的科学合理性进一步探讨;另一个是该处理方法所提供的寻找判别函数达到最小的方法有必要进行改进,否则将对最小值点的精准确定有一定影响。针对上述两个问题,本文提出了Z-I关系最优化处理法的衡量标准,建立了新型的判别函数,同时提出了寻找新型判别函数达到最小值的改进计算方法—变步长循环计算法。     

Algorithm design of an hybrid system embedding influence of soil for dynamic vibration control

The paper outlines an approach for improving the effectiveness and reliability of base isolation devices in civil engineering structures that undergo exceptional dynamic conditions.The strategy consists of designing the passive device in such a way to take into account the not-negligible soil–structure interaction effects. At this stage, the isolator is, then, designed in such a way to be optimally tuned on the basis of the characteristics of the structure and of the soil at the site. Anyway limits intrinsic in the effectiveness of the passive device cannot be completely overcome even when embedding in the design the influence of the soil filtering on the structural response. Therefore, at the second stage, an active vibration device is coupled to the basic isolator, which is, in turn, optimally designed for minimizing the structural response and control costs. The overall presented approach definitively produces an effective hybrid control base isolation, already optimized for the specific structure and soil in its passive component, and able to concentrate the active control effort only on the frequency ranges where it is required.     

前处理方法对北黄海沉积物粒度的影响

采用不同方法对北黄海底质样品进行了粒度分析前处理，以探讨有机质和碳酸盐对北黄海沉积物粒度的影响。结果表明，去除有机质或碳酸盐后，粗粒沉积物（呈双峰分布）粒度分布的峰态明显变宽，平均粒和戏及粗颗粒（＞32μm）组分含量明显增加；而细粒沉积物的粒度分布发生明显细偏，表现为众数的细化及平均粒径和粗颗粒含量的降低。北黄海底质沉积物的有机碳含量变化与沉积物的平均粒径呈明显的负相关，暗示了浅海沉积物中有机碳的输运和积聚主要是伴随着细颗粒组分发生；而碳酸盐含量同沉积物粒度的关系不甚明确，可能与沉积物物源的关系更为密切。     

南极硅藻GJ01(Berkeleya rutilans)产谷胱甘肽条件的优化

以南极硅藻GJ01(Berkeleya rutilans)为对象,分别采用紫外、可见和荧光分光光度法,研究了营养条件等因子对GJ01生长和胞内谷胱甘肽含量的影响,并对培养的GJ01细胞合成谷胱甘肽的条件进行了优化。结果表明,在单因子影响条件下,1.2g/L的碳酸氢钠对南极硅藻GJ01的生长最好,且最有利于谷胱甘肽的积累;0.8mmol/L氯化钙对GJ01的生长最为有利,而0.2mmol/L氯化钙对谷胱甘肽的产生是适宜的;维生素B_(12)和生物素对GJ01胞内谷胱甘肽的产生影响较小。正交试验表明,GJ01细胞产生谷胱甘肽的最优条件是:光照周期为16h/8h、NaHCO_3为1.6g/L、Ca~(2 )为0.4mmol/L、Cys为10mmol/L。该结果为利用南极硅藻GJ01生产谷胱甘肽提供了参考和依据。     

Artificial contradiction between cosmology and particle physics: the Λ problem

It is shown that the usual choice of units obtained by taking G=c=ℏ=1, giving the Planck’s units of mass, length and time, introduces an artificial contradiction between cosmology and particle physics: the lambda problem that we associate with ℏ. We note that the choice of ℏ=1 does not correspond to the scale of quantum physics. For this scale we prove that the correct value is ℏ≈1/10¹²², while the choice of ℏ=1 corresponds to the cosmological scale. This is due to the scale factor of 10⁶¹ that converts the Planck scale to the cosmological scale. By choosing the ratio G/c ³=constant=1, which includes the choice G=c=1, and the momentum conservation mc=constant, we preserve the derivation of the Einstein field equations from the action principle. Then the product Gm/c ²=r _g , the gravitational radius of m, is constant. For a quantum black hole we prove that ℏ≈r _g ²≈(mc)². We also prove that the product Λℏ is a general constant of order one, for any scale. The cosmological scale implies Λ≈ℏ≈1, while the Planck scale gives Λ≈1/ℏ≈10¹²². This explains the Λ problem. We get two scales: the cosmological quantum black hole (QBH), size ∼10²⁸ cm, and the quantum black hole (qbh) that includes the fundamental particles scale, size ∼10⁻¹³ cm, as well as the Planck’ scale, size ∼10⁻³³ cm.      

太湖地区大气气溶胶光学及微物理特征分析

利用2005年9月-2008年6月AERONET太湖站的Level 2.0数据,分析了该地区光学厚度随波长的变化趋势。结果表明,在双对数坐标中太湖光学厚度随波长变化的曲线并非直线,可用二次多项式拟合,气溶胶粒子符合对数正态谱分布。单次散射反照率SSA的变化表明,冬季SSA值较小;春季SSA随波长增大而增大,8、9月SS...     

基于月动力延伸预报最优信息的中国降水降尺度预测模型

利用国家气候中心月动力延伸预报结果、NCEP/NCAR再分析资料和中国160个站观测资料,通过计算两次相关的方法,获取最优预报信息作为建立降尺度预测模型的预测因子,提取的最优预测因子同时满足既是观测环流要素场影响降水的关键区域,又是模式要素场预报的高技巧区域两个条件.结合挑选出的最优预测因子,利用最优子集回归建立月平均降水的降尺度预测模型.文中设计了消除预测因子和预测量的线性趋势值后建立预测模型(方案1)和直接利用原始资料建立预测模型(方案2)两种方案.经过独立样本检验,发现这两种方案建立的预测模型都能够提高月尺度降水预测,方案1对月尺度降水预测的距平相关系数平均可达0.35.利用该方案对超前时间分别为0、5、10 d的月动力延伸预报产品进行月降水的降尺度预测表明,模式初值信息不仅影响月动力延伸预报结果,也影响降尺度应用效果,利用超前时间为0和5 d的月动力延伸预报结果进行降水降尺度预测可在业务中参考.此外,降尺度预测模型中选取的预测因子不仪在统计上是显著的,同时也具有清楚的物理意义.