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21.
22.
L. A. Utracki 《Journal of Polymer Science.Polymer Physics》2004,42(15):2909-2915
The Simha and Somcynsky (S–S) statistical thermodynamics theory was used to compute the solubility parameters as a function of temperature and pressure [δ = δ(T, P)], for a series of polymer melts. The characteristic scaling parameters required for this task, P*, T*, and V*, were extracted from the pressure–temperature–volume (PVT) data. To determine the potential polymer–polymer miscibility, the dependence of δ versus T (at ambient pressure) was computed for 17 polymers. Close proximity of the δ versus T curves for four miscible polymer pairs: PPE/PS, PS/PVME, and PC/PMMA signaled the usefulness of this approach. It is noteworthy, that the tabulated solubility parameters (derived from the solution data under ambient conditions) propounded the immiscibility of the PVC/PVAc pair. The computed values of δ also suggested miscibility for polymer pairs of unknown miscibility, namely PPE/PVC, PPE/PVAc, and PET/PSF. In recognizing the limitations of the solubility parameter approach (the omission of several thermodynamic contributions), these preliminary results are auspicious because they indicate a new route for estimating the miscibility of any polymeric material at a given temperature and pressure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2909–2915, 2004 相似文献
23.
利用量子统计方法 ,直接计算Barriola_Vilenkin黑洞背景下玻色场和费米场的配分函数 ,然后利用砖墙膜模型计算和讨论黑洞背景下玻色场和费米场的熵 相似文献
24.
汤旦林,王松柏.几种国际通用统计软件的比较,数理统计与管理,1997,16(1),48~53.本文对七种著名的国际通用统计软件作了扼要的介绍,并从用户的角度对它们的性能进行了具体的比较 相似文献
25.
Y. Abe 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):143-148
Based on the theory of the compound nucleus reaction, a brief review is given on the special aspects of the reaction dynamics
in the synthesis of the superheavy elements (SHE), where the fusion probability is the most unknown factor. A new viewpoint
of the fusion reaction is proposed that it consists of two processes; the first process up to the contact of two nuclei of
the incident channel and the second one of a dynamical evolution to the spherical compound nucleus from the contact configuration.
The fusion probability is, thus, given as a product of a contact probability and a formation probability. Analytic studies
of the latter probability are discussed in the one-dimensional model, where a simple expression is given to the so-called
extra-push energy in terms of the reduced friction, the curvature parameter of the conditional saddle point and the nuclear
temperature. Preliminary results of numerical analyses of the contact probability are given, using the surface friction model
(SFM). Remarks are given on the present status of our knowledge and for future developments.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
26.
Consider the problem of rolling a dynamically asymmetric balanced ball (the Chaplygin ball) over a sphere. Suppose that the
contact point has zero velocity and the projection of the angular velocity to the normal vector of the sphere equals zero.
This model of rolling differs from the classical one. It can be realized, in some approximation, if the ball is rubber coated
and the sphere is absolutely rough. Recently, J. Koiller and K. Ehlers pointed out the measure and the Hamiltonian structure
for this problem. Using this structure we construct an isomorphism between this problem and the problem of the motion of a
point on a sphere in some potential field. The integrable cases are found.
相似文献
27.
We consider the isothermal flow through a cylindrical flat chamber, a model of some particular heat exchanger, for which LDV measurements and a numerical simulation have been performed. Experimental results show the establishment of an important vortex zone, the secondary flow extending all along the chamber radius. This observation leads to an expected significant increase of the fluid mixing. Results issued from the numerical simulation appear to be in close agreement with experimental data. Nevertheless, the k–ε model used here must be improved to obtain a better approach near the vortex centre. To cite this article: S. Petitot et al., C. R. Mecanique 330 (2002) 593–599. 相似文献
28.
当产品质量指标服从二元正态分时,可用T2控制图与Λ控制图联合判断产品生产的过程是否处于受控状态。本文利用T2统计量与F统计量、Λ统计量与F统计量之间的关系,得到了两指标情形下两类基于F分布统计量的统计过程控制图,简称双F统计过程控制图,并给出了控制图应用实例。 相似文献
29.
CHEN Yue WANG Xuan-jun CONG Xian-ling ZHANG Pei-yin WU Xiu-li WEI Hong-fei WANG Li WAN Min WANG Li-ying YU Yong-li 《高等学校化学研究》2006,22(6):712-716
IntroductionClassical swine fever(CSF), included in the listA of the Office International des Epizooties(OIE), is ahighly contagious disease of domestic pigs and is con-sidered as the mostharmful disease occurring in pigs allover the world[1]. Outbreaks o… 相似文献
30.
John A. Ryan 《Discrete Applied Mathematics》2006,154(2):399-412
We consider irreducible Goppa codes over Fq of length qn defined by polynomials of degree r, where q is a prime power and n,r are arbitrary positive integers. We obtain an upper bound on the number of such codes. 相似文献