偏南气流翻越秦岭山脉的数值分析

通过数值模拟，结果表明风场的垂直结构和热力的共同作用是越山气流扰动不稳定发展和背风波形成的重要条件；水汽作用造成的垂直运动随高度呈抛物线分布；湍流扩散作用不利于上升运动形成。结果还表明，雨峰与上升运动有很好的对应关系，证实了秦岭山脉和越山偏南气流对陕西降水的南北分布有重要贡献     

中尺度冷涡切变暴雨多普勒雷达特征分析

利用天气形势场、物理量场、新一代雷达产品资料对2008年7月17日下午到夜里,豫北、鲁西、冀南地区出现的区域性暴雨天气进行多尺度诊断分析.分析结果显示:较弱的冷性低涡切变本身并不能造成强降水天气,当低涡东移遇副热带高压西北边缘较强暖湿气流时得到加强,在低涡东侧副热带高压边缘切变上产生暴雨天气.冷涡暴雨低层有明显的东北气流冷垫,加强了其动力上升运动,水汽输送依赖于对流层中层的西南气流,中层水汽辐合非常明显.在新一代雷达产品图上显示:较稳定的大范围中等强度回波能产生较强降水.中低层风场为暖平流加辐合,有利于暴雨的形成,中低层较大的垂直风场切变给对流云的形成提供动能,有利于暴雨的产生.     

“7.29”厦门局地短时强降水的成因和预报误差分析

利用常规气象观测数据、NCEP/NCAR FNL再分析等资料以及风廓线雷达、X波段相控阵雷达等新型雷达产品,对2020年7月29日厦门局地短时强降水的成因和预报误差进行分析,结果表明:(1)高层辐散低层辐合配置的强垂直上升运动,中低层较为深厚的水汽饱和层、强热力不稳定、一定强度的风向垂直切变以及较低的自由对流高度等,为局地短时强降水和雷暴大风的形成提供了水汽条件和热力、动力不稳定条件。(2)副高底部偏东气流加强,超低空出现风场辐合,水汽、动力条件转好,热力不稳定条件趋向有利,这些都是当天午后到夜间的局地强降水较预估偏强的原因。(3)925hPa风廓线雷达对此过程风场辐合特征有较好的指示作用,相控阵雷达则清楚显示了过程出现的列车效应,对于局地性的短时强降水可提供更精细的监测数据和降水估计。双偏振参量表明回波有明显的ZDR、KDP异常大值区,表明降水以扁平大水滴为主,回波质心较低,是属于暖云主导的热带降水型,对应雨强较大,降水效率较高。     

非磁化无碰撞热尘埃等离子体中非线性波的自相似解

通过自相似变换,将描述非磁化无碰撞尘埃等离子体集体运动的非线性偏微分方程组化成常微分方程组,在准中性条件下分别得到了绝热和等温过程的解析解。在中性的初始条件下,用自然界2种实际的尘埃等离子体参数,讨论了绝热过程中尘埃颗粒的分布情况和尘埃温度、尘埃带电荷数以及尘埃相对于离子数密度的比率等因素对尘埃颗粒分布的影响,结果显示：尘埃颗粒多分布在时空边缘,时空中心区域稀疏甚至没有尘埃颗粒,且高温、高带电量以及相对于离子数密度比率高的尘埃等离子体中的尘埃颗粒的分布更趋于时空边缘。     

滇西南一次超级单体持续降雹过程分析

利用多普勒天气雷达3830/CC和分辨率为1°×1°的NCEP再分析资料,对一次南支槽影响滇西南超级单体雹暴过程进行分析.结果表明：2 h以上深厚持久中气旋、低层辐合高层辐散和和风速随高度增加等中尺度径向风场结构利于低层暖湿空气辐合进入云体和倾斜旋转上升,形成低层弱回波区(Weak Echo Region,WER)、钩状回波和中高层回波悬垂,北侧冷平流入侵形成“V”型槽口,保障超级单体雹暴持续4 h以上,冰雹粒子强烈散射作用形成旁瓣回波.径向风辐合增强并扩展至8 km高度,回波强度、顶高、50 dBz回波高度、-20℃层回波强度、垂直累积液态水含量(Vertically Integrated Liquid, VIL)等参量波动增大,尤其中气旋非常利于超级单体发展和冰雹粒子生长,在中气旋到达强盛阶段(旋转速度≥10 m·s^-1)26 min内5个特征参量先后出现最大值.南支槽前中层西南气流的汇合提供水汽条件,中低层强垂直风切变提供抬升动力条件,近地层中尺度辐合线创造对流触发条件,低层温湿度锋区提供对流不稳定,而上冷下暖及低层湿度适中、中层高湿、高层干的垂直结构加剧对...     

派比安台风(0606)登陆期间雨带中尺度结构的双多普勒雷达分析

2006年8月3日派比安台风(0606)接近登陆时,在距离台风中心东北180 km处有一强螺旋雨带生成,并随台风往陆地方向移动.本研究利用位于广州和深圳的新一代天气雷达所收集到的双多普勒雷达资料,分析该螺旋雨带的回波结构和中尺度风场,并探讨其维持机制.雷达回波分析显示,雨带由多个对流单体组织成西北-东南走向的带状结构,长约200 km,宽约35 km.同过去研究中台风雨带气流结构呈准二维相比,该雨带在成熟时期的气流结构呈明显的三维特征.从雨带上游至下游,沿雨带方向风速显著减弱,而跨雨带方向风速则明显加强.在雨带上游,雨带内侧为外流,而雨带外侧3 km以下为内流.其中2 km以下气流进入雨带时逐渐减速并在雨带内形成强辐合,部分内流转为倾斜往外的气流.1 km以下,部分内流穿过雨带的强回波中心与雨带内侧的外流在雨带内边缘形成另一强辐合区.在雨带下游,在5 km高度以下雨带内外均侧为内流,其中2 km以下气流从雨带外部进入雨带时先加速,随后逐渐减速,在雨带内侧边缘形成最强的辐合上升运动后,随高度向外倾斜并在雨带外部形成下沉,部分下沉气流转为内流重新进入到雨带.由于雨带上、下游分别位于海洋和陆地上,因此海陆摩擦差异是造成雨带上、下游气流结构差异一个重要原因.而另一个原因是雨带上、下游同以台风中心为圆心的圆周切线间夹角不同.此外,雨带内的气流也表明由倾斜上升在雨带外侧下沉转化成的内流,对于雨带上、下游内流的加强和维持具有重要作用.     

细颗粒长大特性的直接测量

为了研究燃烧源产生细颗粒在过饱和条件下的长大特性,设计了基于冷气流与热水接触形成过饱和环境的生长管来促进细颗粒的长大.利用热风保温的方式防止测量窗口水汽的凝结,从而实现了直接测量细颗粒长大后的液滴粒径分布.利用实验系统研究了热水温度、初始颗粒浓度、气体流量对细颗粒长大特性的影响.实验结果表明:热水温度的上升对细颗粒的长大影响非常明显;而细颗粒的初始浓度增加则不利于细颗粒的长大;气体流量的增大在一定范围内对细颗粒的长大影响较小,而流量大于4 L/min时,则影响较大.在最优的实验条件下,平均粒径为0.197μm的细颗粒长大为5.411μm.     

射频放电尘埃等离子体系统中的斑图现象

在射频放电的尘埃等离子体系统中观察到各种尘埃斑图. 按照尘埃由小到大的生长过程, 将斑图分为两个阶段: 小颗粒阶段(或尘埃云阶段)和大颗粒阶段(或尘埃晶体阶段). 具体研究了气压变化时, 不同斑图之间的演化关系. 小颗粒阶段主要介绍空洞、尘埃声波和强湍流模式. 大颗粒阶段研究了粒子自组织形成的尘埃晶格和尘埃团簇. 通过计算径向分布函数来表征尘埃晶格的静态结构. 还研究了在二维平面上不同粒子数目形成的尘埃团簇, 以及气压变化时尘埃团簇有规律的演化过程. 利用二维径向约束势下的分子动力学模拟验证了二维尘埃团簇的壳层排布规律.     

赣西地区夏季对流云雷达回波特征及人影技术分析

使用2009-2011年天气系统资料和多普勒雷达资料,分析了四种层结条件下萍乡地区的夏季对流云回波特征,结果表明:水汽分布对云体结构有影响,受暖湿平流作用时,大气水汽充分,云体发展旺盛,回波主体半数在0℃附近,对流云可向上延展至过冷却层,有利于混合云降水发生。多普勒雷达的径向速度可以判断对流云的发展阶段,对人影作业的时机把握具有指示意义。     

雷达回波信号的多普勒瞬时频率仿真研究

雷达回波信号是非平稳的时变信号,其瞬时频率是雷达接收机所接收到的回波信号的重要参数,可以获知空间目标的运动信息.本文分析了雷达回波信号处理过程中产生的多普勒瞬时频率的数学基础,其信号频谱峰值随时间的变化而变化,并采用时频分析的方法仿真了多普勒瞬时频率的性能参数,以获得回波信号的多普勒瞬时频率时间域与频率域的联合分布信息,便于获知空间目标的运动情况,更好地探测、跟踪空间运动目标.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to