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111.
硫化天然橡胶物理松弛时间的测量裘怿明刘从伟时锋傅政(青岛化工学院橡胶工程学院青岛266042)关键词硫化天然橡胶,应力松弛速率,数值计算方法,曲线拟合高分子热运动的特点之一是存在松弛现象,通常,人们描述高分子材料的松驰速度采用松驰时间τ[1].实际... 相似文献
112.
113.
Douglas J. White 《Mathematical Programming》1985,31(2):192-205
The Lagrangean function for scalar constrained optimisation problems is extended in a directly analogous manner to constrained
vector optimisation problems. Some simple saddle point results are presented for vector maxima sets. Conditions are given
for the characterisation of the vector maximum set of the original vector problem in terms of the vector maximum sets with
respect to the vector Lagrangeans.
Finally some attention is given to Lagrangean relaxation for vector optimisation problems as an extension of a result of Everett. 相似文献
114.
Gerard G. L. Meyer 《Mathematical Programming》1985,31(1):15-24
Nonadaptive relaxation algorithms require strong continuity assumptions and adaptive relaxation algorithms are computationally
costly. To remedy that situation, an anti-jamming procedure similar to the one used by the author for the method of feasible
directions is proposed. The resulting algorithms are compared with the existing ones for solving unconstrained optimization
problem inE
n
. 相似文献
115.
V. I. Nefedov 《Journal of Electron Spectroscopy and Related Phenomena》1995,70(3):207-215
The influence of the molecular cavity shape and of the angular dependence of the dielectric constants in a low symmetry crystal on the polarization energy Epol, induced by electron holes in the bulk and on the surface of the molecular solids, is investigated. The analytical expressions are obtained and evaluated for SF6, SO2, CS2 and seven aromatic organic compounds. The theory is in good agreement with the experimental data. The deviation of the molecular cavity shape from a sphere has a marked influence on the calculated extra-atomic relaxation energy in large molecules. The Epol value depends on the hole position. In SF6 this value is larger for F atom photoionization than for S atom photoionization. The angular dependence of the dielectric constants has a smaller effect on the Epol value than does that of the cavity shape. The Epol value on the surface of a single crystal depends on the crystallographic plane. The polarization energy for CO molecules on the top of Xe layers on Al(111) is calculated in dependence on the number of Xe layers. The calculated extra-atomic relaxation energy is in good agreement with experiment. 相似文献
116.
The study of transient behaviour of a pulse pumped solid state laser system has assumed importance on account of SLM generation
by self-seeding with the pre-lase signal. This paper reports on the observations of seed pulses for two different Nd: YAG
laser rods, one with anti-reflection coating (AR) on end faces and the other without. The latter displays single longitudinal
mode behaviour in each of the relaxation pulse train while the former displays multimode behaviour. Our observations are well
explained by the ‘active etalon concept’ introduced earlier. 相似文献
117.
本文用相对论动力论方程描述高能重离子碰撞时空演化,并用它分析在200A GeV的16O束流和32S束流下,于快度中心区的末态粒子快度分布,确定了不同系统的弛豫时间. 相似文献
118.
J. F. Rosenblueth 《Journal of Optimization Theory and Applications》1992,74(3):509-526
In a recent paper, we proposed different relaxation procedures for optimal control problems involving time delays in the control functions. We introduced a notion of proper relaxation, applicable to problems without side constraints, where we required the minimum cost of the relaxed problem to coincide with the infimum cost of the original one. In this paper, a new and appropriate notion of relaxation for problems with side constraints is introduced. As examples of proper extensions, in the new sense, we describe in detail the standard procedure for delay-free problems and the procedure for one-delay systems which we recently proposed. 相似文献
119.
We describe an algorithm for the asymmetric traveling salesman problem (TSP) using a new, restricted Lagrangean relaxation based on the assignment problem (AP). The Lagrange multipliers are constrained so as to guarantee the continued optimality of the initial AP solution, thus eliminating the need for repeatedly solving AP in the process of computing multipliers. We give several polynomially bounded procedures for generating valid inequalities and taking them into the Lagrangean function with a positive multiplier without violating the constraints, so as to strengthen the current lower bound. Upper bounds are generated by a fast tour-building heuristic. When the bound-strengthening techniques are exhausted without matching the upper with the lower bound, we branch by using two different rules, according to the situation: the usual subtour breaking disjunction, and a new disjunction based on conditional bounds. We discuss computational experience on 120 randomly generated asymmetric TSP's with up to 325 cities, the maximum time used for any single problem being 82 seconds. This is a considerable improvement upon earlier methods. Though the algorithm discussed here is for the asymmetric TSP, the approach can be adapted to the symmetric TSP by using the 2-matching problem instead of AP.Research supported by the National Science Foundation through grant no. MCS76-12026 A02 and the U.S. Office of Naval Research through contract no. N0014-75-C-0621 NR 047-048. 相似文献
120.
It is shown that presentation of viscoelastic data in the modulus/frequency form is dominated by the interaction between the infinite frequency compliance and the viscosity. Therefore this form of presentation is insufficient to allow evaluation of the differences in behaviour between viscoelastic materials. 相似文献