Phase measurement accuracy of feedback interferometers

Feedback interferometers are described with specific reference to potential applications in micro-machines. A theoretical analysis is developed to determine the linearity, stability, and noise performance of this type of interferometer. The theoretical analysis was tested using a prototype high-precision feedback interferometer which showed that, at a feedback loop gain which enabled the system to track 6 fringes, the linearity of the interferometer was better than λ/100 and single phase measurements could be made with an accuracy of λ/80.     

An algorithmic approach for a special class of Markov chains

In this paper, we develop an algorithmic method for the evaluation of the steady state probability vector of a special class of finite state Markov chains. For the class of Markov chains considered here, it is assumed that the matrix associated with the set of linear equations for the steady state probabilities possess a special structure, such that it can be rearranged and decomposed as a sum of two matrices, one lower triangular with nonzero diagonal elements, and the other an upper triangular matrix with only very few nonzero columns. Almost all Markov chain models of queueing systems with finite source and/or finite capacity and first-come-first-served or head of the line nonpreemptive priority service discipline belongs to this special class.     

Models of a structural phase transition with general anharmonicity and disorder

It is shown how the self-consistent phonon Ansatz leads to a new class of exactly soluble models of a structural phase transition. Both nonpolynomial anharmonicity and disorder are analyzed in detail. In the classical limit, the thermodynamics is obtained and sufficient conditions on the anharmonicity are given to ensure a soft-mode phase transition. Diagonal disorder has been studied numerically. It is found that in three dimensions a pronounced mobility edge, separating localized and delocalized phonon states, may exist.     

挤出机螺栓失效分析

作者通过各项测试、断口分析及有关机械设计计算,较全面地分析了螺栓的失效形式及原因,并提出防止失效的措施,从而为保证挤出机的正常运转和安全生产提供了有益的依据,也为探讨失效分析技术在机械零部件方面的应用提供有效的方法。     

多品种随机量—本—利分析

讨论了在产品市场价格、单位变动成本、产销量、固定成本和社会对企业产销多品种产品的货币投入量为不确定性情况下,随机量一本一利模型的建立,分析了模型下的企业决策问题,并通过实例将其结果加以应用。     

A Bahadur efficiency comparison between one and two sample rank statistics and their sequential rank statistic analogues

One and two sample rank statistics are shown in general to be more efficient in the Bahadur sense than their sequential rank statistic analogues as defined by Mason (1981, Ann. Statist.9 424–436) and Lombard (1981, South African Statist. J.15 129–152), even though the two families of statistics (those based on full ranks and those based on sequential ranks) have the same Pitman efficiency against local alternatives. In the process, general results on large deviation probabilities and laws of large numbers for statistics based on sequential ranks are obtained.     

现代组合机床技术及其发展

本文介绍了现代组合机床技术发展的主流。分析了组合机床柔性化的几个主要方面,以及通用部件、加工精度、应用范围方面的现状及发展。最后从柔性制造技术角度介绍了组合机床综合自动化技术的发展新动向。     

An exactly soluble case of the triangular ising model in a magnetic field

An anisotropic triangular Ising model in which the first- and second-order parameters and the field parameters are functionally related is solved exactly by representing the distribution of the atom patterns in terms of a suitably constructed Markov process. The probabilities of patterns, defined as the probabilities generated by this process, are a mathematically tractable alternative to the classical representation of these probabilities in terms of the partition function. The interaction and field parameters of this Ising model, its magnetization, free energy, and its nearest neighbor correlation functions, are expressed in terms of the parameters of this Markov process. Special cases are worked out in detail and numerical examples are given.     

Molecular beam study of photoionization of uranium and uranium oxide

Crossed laser molecular beam configuration was used to study the photoionization of U and UO by the UV-lines of an argon ion laser. Photoionization efficiencies of both U and UO were found to be line sensitive. Photoionization by the 3638 Å line was observed for the first time. Uranium atom ionization efficiency being higher for the 3345 Å and 3511 Å groups of lines, while UO ionization efficiency being maximum for the 3638 Å line. Dependence of photoion signal on laser power and relative photoionization efficiencies of the two isotopic species of uranium are also investigated.     

Studies of Ziegler-type catalysts for the polymerization of ethylene and propylene II The polymerization of ethylene with VOCl3-Et3Al2Cl3 (chlorinated activator) catalysts

VOCl₃-Et₃Al₂C1₃(chlorinated activator) catalysts have been employed for the polymerization of ethylene at T between 15 and 85° in n-hexane. Using butylperchlorocrotonate as the activator, the following catalyst efficiencies (g polymerization, hr, atmosphere ethylene in the cap gas) were achieved: 10^6,1 MFI = 0-00; 10^5,8, e.g. MFI = 1 0 (with 9 per cent H₂ present in the cap gas) and 10^6–9 MFI = 0?4 (with 44 mmole/1 styrene in the hexane medium). Reactions between the aluminium alkyl and the activator molecules produced other chlorinated species of high average activator effectiveness. The catalyst system could be reactivated by further additions of Et₃Al₂Cl₃. The minimum value of the polymerization propagation rate constant is estimated to be 10¹²²?6x10,461 cm³/mole sec.