A-调和函数的加权Caccioppoli型不等式

设u∈W1p,loc(Ω)是A-调和函数.如果1＜s＜p＜∞,测度μ(z)定义为dμ=w(z)dx,那么存在常数β＞1,使得w∈A1r∩ As/p,sβ/(β-1)≤k＜p时,有(1/|B|∫B |φ▽u|swdx)1/s≤c(1/|B|∫B|u▽φ| pwdx)1/p.对所有的球或立方体B Rn和所有的φ∈C∞0(Ω)都成立.这里C是一个不依赖于u和▽u的常数.     

粗糙底床对持续入流式异重流掺混和湍流特性的影响

在自然环境和水利工程中,异重流现象广泛存在.现实工况中,大多数底床覆盖砾石及不同粒径大小的泥沙颗粒,可视为粗糙底床,因此研究异重流流过粗糙底床的动力学特性具有实际科学意义及工程应用价值.本文利用持续入流式异重流水槽试验,综合考虑底床粗糙度和异重流初始质量分数,分析异重流头部位置、头部速度、掺混系数等扩散特性,不同断面的湍流强度及雷诺应力等湍流特性,结合雷诺应力法和湍动能法计算底床剪应力.结果表明:异重流头部速度与底床粗糙度呈负相关,与初始质量分数呈正相关;在高粗糙度、高初始质量分数工况时,底床粗糙度是控制其运动特性的主要因素;当粗糙度增加到一定程度时,异重流纵向时均流速剖面(沿水深分布)的峰值点出现"爬升现象";湍流强度剖面(沿水深分布)出现一个极小值及两个极大值,其中纵向湍流强度是异重流湍流结构的主导,粗糙底床上的垂向湍流强度相比于光滑底床增加幅度明显;靠近底床附近,雷诺切应力为正值,远离底床区域,雷诺切应力为负值;利用湍动能法计算的底床剪应力均小于同粗糙度下的雷诺应力法;在总体理查森数相同情况下,异重流掺混系数与底床粗糙度呈正相关.最后总结出粗糙底床对异重流的主要影响为:摩阻力增加、掺混作用强化、近底床区域密度重分布、湍流边界层变厚及纵向时均流速剖面峰值点"爬升现象"的出现.     

城市雨水口流场及紊动特性试验研究

基于具有上下两层结构的城市洪水综合试验平台,使用三维超声多普勒流速仪(ADV)测量较大水深条件下雨水口周边流速与紊动强度的三维分布.试验结果表明:当来流水深较大时雨水口中心会出现一地漏漩涡,来流与漩涡共同作用引起雨水口周边流速显著增加.漩涡中心处流速相对较大且流速纵向分量与来流方向相同侧平均流速大于相反侧,各试验工况条件下最大流速均位于雨水口下游边缘附近.雨水口引起的漩涡增大了水体的紊动强度,紊动强度的平面分布与流速平面分布较为类似,工况2条件下平均湍流动能由水槽进口处0.004m2/s2增加至雨水口下游边缘处0.145m2/s2.水体剧烈的紊动效应使底床摩阻的影响相对减弱,流速沿垂线呈常数型和线性型分布,不符合明渠水流对数型的分布特征.     

一类非线性椭圆型方程弱解的—C~(bα)正则性

研究了非线性椭圆型方程—div A( x, u) f( x) =B( x,u, u) ,在可控增长条件| B( x,z,h) |≤∧1| h| p( 1- 1/p* ) | z| p* - 1 g( x) 下 ,得到弱解的 C1,α正则性 ,其中 1 相似文献   

基于层析PIV的湍流边界层涡结构统计研究

本文运用层析PIV技术测量了Re?=1768的平板湍流边界层,得到了250个瞬时三维三分量(3D3C)速度场.测量体位于边界层对数区,其大小为80 mm×16 mm×45 mm.旋涡强度ci?准则用来进行涡识别,以ci?在各个方向的投影作为该方向上的旋涡强度.本文通过线性随机估计、预乘功率谱等技术对湍流边界层中的涡结构进行了统计分析.结合高低流速区域,发现强剪切区域存在周期性分布的涡结构.最后用本征正交分解对流场进行尺度分离,发现大尺度结构对应的速度分布接近原始流场,而小尺度流场的涡量分布和频谱特性与原始涡量分布高度吻合.     

推广的反应扩散方程的不变集和精确解

利用屈长征,Estevez提出的推广的不变集S_1={u:u_x=(1/x)F(u) зF(u)[exp(n-1)~n∫(1/F(z))dz]}求推广的反应扩散方程u_x=A(u)u_(xx) B(u)u_x~2 C(u)u_x D(u)的精确解,给出了推广的方程的一些特殊解,丰富了推广的方程的解.     

刚性沉水植物影响下波浪传播及泥沙悬浮数值模拟

由于植物引起的紊动作用,含刚性植物床面中悬浮泥沙浓度与无植物裸床相比显著增加,而通过平均流速计算底床切应力的传统泥沙模型无法模拟出该现象。因此,在含植物水流水沙运动物理模型试验的基础上,构建了基于Flow–3D的含刚性沉水植物条件下波浪传播的三维数学模型,模拟了植物影响下波浪动力特征和泥沙悬浮过程,同时从紊动能角度修正希尔兹数,对泥沙模块进行了改进。与实测数据相比,该模型可较精确地模拟出植物引起的整体水流流速减小和局部冠层顶部处的流速增大、水体紊动增强以及紊动能在波周期内出现两个峰值的现象。与原始泥沙模块相比,改进的模型考虑了植物尾流紊动对泥沙运动的影响,可提高含植物床面泥沙悬浮模拟的精度。     

型为44的OGDD的同构分类

正交可分组设计是一个四元组(X，Y，A，B），其中X是一个点集，Y是X的一个划分(称为组集)，A和B是两个不交的三元子集簇，满足对不在同一组的任一点对{x，y}恰好出现在A的一个三元集中，也恰好出现在B的一个三元集中．进一步有(a)如果{x，y，a}∈A且{x，y，b}∈B，那么a和b不在同一组，且(b)如果{x，y，z}，{u，v，z}∈A且{u，v，b}，{x，y，a}∈B，那么a≠b，在这篇文章中，将证明只有一个型为4^4的OGDD的同构类．     

一类与I_n算子有关的解析函数的Fekete-Szeg不等式

引入了一个与算子I_n有关的解析函数类Q(a,n;A,B),利用函数的极值和单调性,讨论了此函数类的a_3-ua_2~2不等式.假设f(z)∈(a,n;A,B),u∈C,则有a_3-ua_2~2≤(A-B)(n+1)(n+2)/18(1+2a)max {1,|9u(A-B)(1+2a)(n+1)/8(1+a)~2(n+2)+B},|a_2|≤(A-B)(n+1)/4(1+a),且对所有的u等号都成立.当参数a、B、A取一些特殊值时,得到一些特殊函数类的Fekete-Szeg不等式.     

清水冲刷下均匀天然沙含沙量恢复过程试验研究

水库修建后,清水下泄将造成坝下游河道处于冲刷状态,引起河势调整,给下游防洪、水资源利用及航运等可能带来一系列不利的影响;由于坝下游清水冲刷过程的复杂性,沙质河床含沙量沿程恢复规律一直是河流泥沙动力学的难度问题之一.基于此,首先本文根据湍流猝发理论推导出清水冲刷下沙质型河床含沙量沿程恢复的理论公式,然后利用配置精密仪器的变坡水槽试验进行相关研究,并根据试验数据分析不同条件下垂线平均含沙量沿程恢复的特性.试验成果显示,当流量、床沙粒径不变,河床比降为0.5‰、1.0‰与2.0‰时,垂线平均含沙量恢复过程差异性较小,但随着冲刷距离发展α_1(近底处含沙量与垂线平均含沙量比值)递减而α_2(近底处挟沙能力/垂线平均挟沙能力比值)略有增加,且在清水冲刷发展过程中α_1是一个逐渐靠近α_2的动态变化过程;当床沙粒径与河床比降不变,流量越大,水流垂线平均含沙量恢复饱和的数值与距离越大,α_1、α_2数值同样也越大;当流量、河床比降不变,床沙粒径颗粒越细,含沙量恢复饱和时的数值越大,恢复距离也越长,反之亦然.     

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.     

A computer generator for randomly layered structures

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

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。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

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     

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

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

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.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.