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1.
采用自洽场方法(HF)和密度泛函(DFT)的B3LYP方法,在6-31G^*水平下,研究了H6M4(N2H2)3(a—M=Al,b—M=Ga)簇合物的几何构型、电子结构、红外光谱及热力学性质.结果表明:N—N键比肼中N—N键长,有进一步裂解的趋势.振动频率计算表明:铝、镓的肼簇合物为基态稳定结构.  相似文献   

2.
从热力学角度研究了小分子溶剂与高分子混合体系的溶液--液晶相平衡性质。研究发现,高分子链越长,形成液晶的极阴浓度越小;当高边节小于4.2时,体系不可能形成液晶。  相似文献   

3.
该文采用统计力学的方法,将长链PDMS分子作为一个约束在圆柱体内的小体系进行处理,利用计算机进行模拟PDMS链的动态过程和处理矩连乘,坐标转换,得出受约有限长度高分子链的配方函数表达式。  相似文献   

4.
针对JXTA对等网络RPV发现机制存在效率低下的问题,提出了一种基于小世界的改进方案。该方案利用Kleinberg的小世界理论,将RPV表分解为本地短链RPV(S)表和长链RPV(L)表,本地短链RPV(S)表可以保证搜索的获得性和可靠性,长链RPV(L)表可以实现快速搜索,同时采用概率置换长链策略构造长链RPV(L)表。研究表明,该方案可以保证JXTA对等网络的平均跳数为0(log^2N)。  相似文献   

5.
应用二阶格式函数方法。研究了双二次相互作用项对反铁磁海森堡链激发谱和热力学性质的影响,目前用二阶格林函数方法研究此类问题尚未见报导。研究发现随着双二次相互作用的增强,反铁磁海森堡链的Haldane能隙将降低,内能增加,比热曲线的峰质左移,并且存在一个双二次相互作用临界值ac,当a〉ac时,将得不到体系的激发谱。  相似文献   

6.
研究了水下圆柱体带空泡轴向绕流问题.用数值方法研究了不同长细比圆柱体水下运动产生空泡的形态及圆柱体水下带空泡绕流的阻力特性,圆柱体绕流空泡形态以及阻力系数数值计算结果与试验对比,符合较好.圆柱体长细比对空泡形态影响可以忽略.随长细比增大:空化数较高时,阻力系数先减小后增大;空化数较小时,其阻力系数基本保持不变.小空化数条件下,给定长细比,空化数越小,阻力系数越小.  相似文献   

7.
用数学分析方法研究总结了恒定组成封闭体系的热力学函数之间的关系式,为较好地研究体系热力学参数之间的关系奠定基础,也为物理化学教学提供一定的思考问题的方法和理论。  相似文献   

8.
OP—7/醇/正庚烷/HC1体系形成微乳液的势力学性质研究   总被引:1,自引:1,他引:0  
研究了OP-7/醇/正庚烷/HCl体系形成微乳液的热力学函数,考察不同碳链长度的醇对微乳液形成和稳定性的影响。  相似文献   

9.
采用仿制的改良型DVorak-Boublik平衡鉴测定了水—N、N—二甲基甲酰胺(DMF)体系的400mmHg下的汽液平衡数据。对所测数据用经验方法进行了热力学一致性的校验,分别用Vanlaar;Margules;Wilson和UNIφAC方程进行了热力学关联和比较,提出了所研究体系的最佳方程和配偶参数,编制了计算活度系数、泡点和汽相组成的计算机程序。为设计现代聚丙烯睛干法纺丝新工艺的溶剂D.M.F的回收所用减压精馏装  相似文献   

10.
结构—SRK状态方程参数关系的研究   总被引:2,自引:0,他引:2  
以一阶分子连接性指数^1X为分布变量,研究了链烷烃SRK状态方程参数与^1X的关系。结果表明这些参数与^1X有着良好的相关性,这些关系可用于石油馏分中链烷烃组成的预测和与链烷烃有关的连续热力学计算、研究及状态方程参数估值。  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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
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   

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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