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1.
在微扰QCD O(αs)领头阶对数近似下,采用双重Q^2-重标度模型,计算了P-A碰撞Drell-Yan过程K因子,并与P-N碰撞Drell-Yan过程K因子进行比较。计算结果表明K因子对核质量数A有很强的依赖性,且在xA〈0.1区域,随xA的减小核效应越显著。与未来实现相对照,可以检验所用的核效应理论模型及微扰QCD理论。  相似文献   

2.
在Drell-Yan过程中计入湮灭项和康普顿散项的贡献,利用双重Q^2-重标度模型,计算了碳核与碳核碰撞在给定不同的xA1值时K因子随xA2的变化结果表明,对应不同的xA1值,K因子随xA2的变化曲线形状很不相同。计算结果与实验对照可以检验所用核效应的模型及QCD理论。  相似文献   

3.
在微扰QCDαs近似下,采用双重Q^2-重标度模型,计算了as级QCD修正对P-A(^12 6C,40 20Ca,^56 26Fe)碰撞Drell-Yan过程微分截面的贡献,说明了对于核Drell-Yan过程截面的计算,QCD修正是不容忽略的。  相似文献   

4.
提出了一个由l-A的深度非弹性散射和核Drel-Yan过程的实验数据得到价夸克分布和海夸克分布的核效应的函数RAv(xt)和RAs(xt)的方法.这两个函数可以用来检验核子结构函数的核效应的理论模型.文中以钙核为例求出了RCav(xt)和RCas(xt).  相似文献   

5.
提出了一个由1-A的深度非弹性散射和核Drel-Yan过程的实验数据得到价夸克分布和海夸克分布的核效应的函数RAV(xt)和RAs(xt)的方法。这两个函数可以用来检验核子结构的核效应的理论模型。文中以碳核为例求出了RCv(xt)和RCs(xt)。  相似文献   

6.
提出了微扰QCD的高级修正K因子的经验公式,与有关实验符合得相当好。K因子随m的增大而缓慢减小这一事实支持了QCD渐进自由性质的一贯要求和以往关于K因子的直接实验结果。指出各种D-Y过程的动力学实质相同,K因子经验公式的动力学实质有待进一步研究。  相似文献   

7.
利用混合重标度模型计算铁核与氘核的Drel-Yan截面比随xF的变化,计算结果与实验符合较好  相似文献   

8.
价夸克分布与海夸克分布的核效应   总被引:2,自引:0,他引:2  
由l-A深度非弹性散射实验数据结合p-A碰撞Drell-Yan截面数据来分别考察束缚核子中价夸克分布与海夸克分布的核效应,提出了一种检验解释EMC效应的理论模型的方法。  相似文献   

9.
提出了一个由轻子-核深度非弹性散射和核Drel-Yan过程的实验数据得到价夸克分布和海夸克分布的核效应函数RΑυ(χt)和RAs(χt)的方法。由这两个函数可以检验解释核效应的理论模型。以铁、钙、碳核为例进行了讨论  相似文献   

10.
利用QCD求和规则,在忽略奇异海夸克效应近似下,计算了核子同位旋标量轴矢流耦合常数gA^s。在极化函数物非微扰部分,本文计算了∫0×1dxg1^(p)(x)的三胶子凝聚修正。在QCD修正的组合夸克模型中,分析了质子的自旋结构函数,并得到S夸克对gA^s的贡献。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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。  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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.  相似文献   

16.
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。  相似文献   

17.
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.  相似文献   

18.
19.
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  相似文献   

20.
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  相似文献   

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