An Enumeration of Binary Self-Dual Codes of Length 32

A binary self-dual code of length 2k is a (2k, k) binary linear code C with the property that every pair of codewords in C are orthogonal. Two self-dual codes, C ₁ and C ₂, are equivalent if and only if there is a permutation of the coordinates of C ₁ that takes C ₁ into C ₂. The automorphism group of a binary code C is the set of all permutations of the coordinates of C that takes C into itself.The main topic of this paper is the enumeration of inequivalent binary self-dual codes. We have developed algorithms that will take lists of inequivalent small codes and produce lists of larger codes where each inequivalent code occurs only a few times. We have defined a canonical form for codes that allowed us to eliminate the overenumeration. So we have lists of inequivalent binary self-dual codes of length up to 32. The enumeration of the length 32 codes is new. Our algorithm also finds the size of the automorphism group so that we can compute the number of distinct binary self-dual codes for a specific length. This number can also be found by counting and matches our total.     

An analysis of states in the phase space: the diatomic molecules

Summary The paper concerns a theoretical model to calculate the number of allowed states for the electrons in the diatomic molecules through the quantum-statistical analysis of the phase space. The approach is a straightforward extension of that already discussed in the case of many-electron atoms. Simple formulae are derived that enable to calculate the dissociation energy, bond length and vibrational frequency of diatomic molecules in a good agreement with the experimental data.     

Band effects on conduction electron density of states for the anderson model

Summary The effects of the shape of free conduction density of states on the physical quantities for the periodic Anderson model have been investigated.     

Expert knowledge and computer-aided group decision making: Some pragmatic reflections

Based on a simple outranking method of multi-attribute decision making (MADM), called Dichotomy-Cut, developed in recent years and published elsewhere, this paper describes how to reliably elicit the necessary decision knowledge for implementing various decision modes via this method and its computerized support - UNIDAS 2. The most important features of this method are outlined, namely, how to compose the preference ordered matrices and which are the basic decision rules. Special attention should be paid to specific interactive group decision behaviour of experts. Two examples plainly explain the contents discussed.     

Development of high resolution silicon surface barrier detectors

Fabrication methods for silicon surface barrier detectors and their correlated properties which result in the production of high resolution (< 20 keV) devices have been studied. The techniques for fabrication and testing of the detectors currently employed at our Centre are presented. An FWHM of 14keV for 5·486 MeV²⁴¹Am α has been achieved. Our results are therefore comparable with the best in the world.     

Approximation of nonlinear functional differential equation control systems

We develop a general approximation framework for use in optimal control problems governed by nonlinear functional differential equations. Our approach entails only the use of linear semigroup approximation results, while the nonlinearities are treated as perturbations of a linear system. Numerical results are presented for several simple nonlinear optimal control problem examples.This research was supported in part by the US Air Force under Contract No. AF-AFOSR-76-3092 and in part by the National Science Foundation under Grant No. NSF-GP-28931x3.     

Three-dimensional immiscible lattice gas: Application to sheared phase separation

A new lattice-gas cellular automaton model for simulating binary fluids in three dimensions is introduced. It is particularly suitable for modeling slow flows of mixtures with complicated interface geometries or within complicated boundaries, such as in the interior of a porous rock. Phase separation is triggered spontaneously in the model by statistical fluctuations and phase domains are approximately isotropic. The measured surface tension is large compared to that in analogous two-dimensional models. The model is applied to a study of the time-dependent effective viscosity of a phase-separating mixture in a simple shear flow. Results qualitatively match both experiment and theory: the viscosity increases rapidly, then decays gradually to a steady-state value which is larger than the viscosity of the pure fluids. The effective viscosity increases with increasing concentration and decreases with increasing strain rate.     

一类随机递归集的重分形分解

本文讨论了一类广义的随机递归集的重分形性质,通过将其构造中的子集间的不重叠条件减弱到有限交性质,使得子集间允许适当重叠,同时保证递归集不为空集和其重分形维数计算仍具有明显的表达式.     

低温等离子体表面处理技术在生物医用材料中的应用

合成高分子材料无法完全满足作为生物医用材料所需要的生物相容性和高度的生物功能要求，为解决上述问题，文章介绍了一种表面处理方法－等离子体表面改性技术以其特有的优点在生物医用材料中的应用情况，通过等离子体处理后，能够在高分子材料表面固定生物活性分子，达到为生物医用材料的目的。     

On the steady-state queue size distribution of the discrete-timeGeo/G/1 queue with repeated customers

In this paper, we study the steady-state queue size distribution of the discrete-timeGeo/G/1 retrial queue. We derive analytic formulas for the probability generating function of the number of customers in the system in steady-state. It is shown that the stochastic decomposition law holds for theGeo/G/1 retrial queue. Recursive formulas for the steady-state probabilities are developed. Computations based on these recursive formulas are numerically stable because the recursions involve only nonnegative terms. Since the regularGeo/G/1 queue is a special case of theGeo/G/1 retrial queue, the recursive formulas can also be used to compute the steady-state queue size distribution of the regularGeo/G/1 queue. Furthermore, it is shown that a continuous-timeM/G/1 retrial queue can be approximated by a discrete-timeGeo/G/1 retrial queue by dividing the time into small intervals of equal length and the approximation approaches the exact when the length of the interval tends to zero. This relationship allows us to apply the recursive formulas derived in this paper to compute the approximate steady-state queue size distribution of the continuous-timeM/G/1 retrial queue and the regularM/G/1 queue.Partially supported by the Natural Sciences and Engineering Research Council of Canada through grant OGP0046415.Partially supported by the Natural Sciences and Engineering Research Council of Canada through grant OGP0105828.