绝热放电现象和粒子碰撞对磁化尘埃等离子体中、低频静电波稳定性的影响

考虑到尘埃绝热放电现象、外磁场、碰撞、离子与尘埃温度之比、电子与离子数密度之比以及斜传播等因素对均匀尘埃等离子体中低频静电波的影响，其中包括高能离子和玻耳兹曼分布电子，运用简正模分析法，得出了低频波的色散关系．研究表明，以上诸因素对低频波有很大影响．研究中包括两种不同的低频波模式．在研究斜传播对低频波的影响时，发现当θ=π／2时，第一种模式是稳定的；而第二种模式存在一个稳定区域，即1.3≤θ≤1.7.     

绝热放电和粒子碰撞对磁化等离子体中三维尘埃声孤子波的影响

考虑了尘埃绝热放电、外磁场和碰撞等因素对尘埃等离子体动力学行为的影响,运用约化摄动法,得出三维尘埃声孤子波的KdV方程.研究结果表明,仅仅存在稀疏型孤立波,而且z方向波矢、离子温度和电子-离子数密度之比(μ)等因素对孤立波的波幅和波宽都有显著影响,外磁场和碰撞频率只对波宽有影响.在研究波宽随μ的变化规律时,发现μ存在一个临界值μc,当μcμ时,波宽随μ的增大而减小.     

包含双温非热离子的尘埃等离子体中的三维尘埃声孤波

考虑高阶横向扰动的因素,使用约化摄动方法得到描述含有双温非热离子的无磁化尘埃等离子体中的尘埃声波的(3+1)维KP方程.详细讨论一些尘埃等离子体系统参数如电子与非热高温离子数密度v与μh、快离子数λ(α)、低温非热离子与电子的温度比1β、非热双温离子温度比2β对尘埃声孤波性质的影响.研究结果表明:这些因素均可显著影响和改变孤波结构.在考虑双温非热离子后,稀疏形孤波与压缩形孤波的临界条件也发生极大变化.     

关于非线性离子声波和孤波在磁化等离子体中的传播

考虑到非准中性条件,我们计算了离子声波和离子回旋波在低β磁化冷等离子体中斜传播的数值解,结果发现产生离子声孤波的条件比传统用准中性条件得到的要宽,即当θ很小时,离子声马赫数,M相似文献   

多组分复杂等离子体中(2+1)维非线性离子声孤波的传播特性研究

研究了复杂等离子体中(2+1)维非线性离子声孤波的传播特性.应用约化摄动法推导得到了用来描述含有非广延电子-正电子分布的多组分尘埃等离子体中(2+1)维非线性离子声孤波的Kadomtsev-Petviashvili(KP)方程.获得了非线性离子声孤波的非线性强度、振幅与宽度等传播特性随系统参数的变化规律,明确了系统参数对(2+1)维非线性离子声孤波传播特征的重要影响.     

非线性尘埃声波在含有2种不同温度离子的尘埃等离子体中的稳定性问题

在无磁场的尘埃等离子体中 ,由冷的尘埃颗粒和热的电子和离子组成的尘埃等离子体 ,对于有限的小振幅的非线性波的运动可以用KdV方程描述 .对由 2种不同温度离子的尘埃等离子体中的弱二维尘埃声波 ,得到了它所满足的KP方程 .并且发现 ,在横向扰动下 ,弱的非线性孤立波在尘埃等离子体中是稳定的 .在这个系统中既存在压缩孤立波又存在稀疏孤立波     

非绝热尘埃等离子体中的（2＋1）维尘埃声孤波

运用约化摄动方法研究了尘埃等离子体中离子呈现非绝热分布状态时(2 1)维尘埃声波的基本传播特性,得到了描述尘埃声波运动的Kadomtsev-Petviashvili(KP)方程.借助数学软件讨论了不同参数对尘埃声孤波传播特征的重要影响.     

尘埃电荷变化和粒子碰撞对尘埃等离子体中三维尘埃声激波的影响

考虑了尘埃非绝热放电和碰撞等因素对尘埃等离子体动力学行为的影响,运用约化摄动法,得出了描述三维尘埃声激波的Korteweg-de Vries-Burgers(KdV-Burgers)方程,并运用数值积分对激波特性作了详尽地分析和说明.研究结果表明,碰撞频率、电子-离子数密度之比等因素对激波的性质有显著影响.     

含有非热力学平衡离子和尘埃颗粒电荷变化的热尘埃等离子体中的尘埃声波

使用约化摄动法得到了描述含有尘埃颗粒电荷变化、非热力学平衡离子和玻尔兹曼分布的电子的热尘埃等离子体中尘埃声波修正的KdV(mKdV)方程.并对孤立波受尘埃流体、离子和电子的温度,非热力学平衡快离子参数,尘埃电荷变化以及尘埃颗粒、离子和电子数密度的影响进行了数值模似.     

多离子等离子体中斜传播左旋离子回旋电磁波的特性

系统研究了多离子等离子中斜传播左旋离子回旋电磁波(EMIC)的特性.针对高、低两种地磁活动(ρ=1,100),计算了Stix参数D,S的数值,发现了多离子EMIC波色散关系的一个新特点:斜传播的多离子EMIC波在参数D的零点处分开,在He+和H+波段EMIC波禁止传播的区域随传播角增大而增大.这点与单离子EMIC波显著不同.此结果表明,Stix参数D,S是决定EMIC波色散特性的重要因素.     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the