用热涨落理论对塑料发泡中经典成核理论应用的修正

分析了经典成核理论对塑料发泡成核的解释,并从微泡实验的实验数据出发分析了实验与理论的偏差;在应用热涨落理论,修正了经典成核理论,导出新的成核模型,并比较了修正后理论与中成核率与释压压差的函变关系的结果。     

推拉结合的生产计划与控制方法的应用研究

为解决制造企业生产系统面临的多品种、小批量的计划与控制问题，参考当前流行的生产管理理论，提出了一种推拉结合的生产计划与控制方法．该方法将MRP、JIT和TOC理论在不同计划和控制层面上进行综合应用，辅助车间快速有效地实现生产作业控制．该方法在制造执行系统（MES）平台的具体实现及在某制造型企业的应用验证了其可行性和有效性．     

Time-dependent behaviour of reacting concrete II: Applications and discussion

In Part I of the paper, the Dissolution-Precipitation Mechanism explaining the mechanical behaviour of reacting concrete has been presented and a theory of isotropic linear elastic reacting solids has been proposed. In this Part II of the paper, the above micromechanical mechanism and theory have been discussed. The possible contribution made to the theoretical mechanics of time-dependent materials has been critically examined. The proposed theory has been applied to evaluate the mechanical effects like creep, recovery and relaxation of stressed concrete due to various types of ongoing common chemical reactions. The importance of including stress as a parameter in the investigations on the durability of concrete has been brought out. Finally, the durability problem has been recast as a chemico-mechanical problem.     

Why has Latour's theory of citations been ignored by the bibliometric community? discussion of sociological interpretations of citation analysis

The paper discusses the often lamented lack of a theory of citations, and the lack of a sociological theory in particular. It draws attention to one proposed theory and discusses the potential reasons why it has not been generally accepted as the theory of citations, despite its merits in explaining many phenomena in the citation behaviour of scientists. This theory has been expounded by Latour and presented, in particular, in his book entitledScience in Action.     

Structural and statistical model of a hard alloy with damages

An approach to a construction of the micromechanical theory of the hard alloy strength has been proposed, which is based on a combination of the structured modeling and statistical theory of extreme values. Computational experiments using the structural model have been performed with the aim to construct a continual theory of the accumulation of damages in a hard alloy and revise parameters that form a part of criteria for strength and life of hard alloy products. The introduced micro damage parameter has been related to the Pisarenko-Lebedev criterion for static strength. The possibility to improve the proposed theory and its application in practical calculations of strength and durability of hard alloy products has been discussed.     

On the mathematical theory of the microstructure evolution during the final stage of liquid phase sintering

A new mathematical theory of the microstructure evolution during the final isothermal stage of liquid phase sintering has been developed. The basis of this theory has been formed by materials science and continuum mechanics. The microstructure evolution has been described by the system of non-linear differential equations, which contain more than ten parameters. Finite difference analysis has been performed for a heavy alloy cylindrical specimen. The results of the calculations have been compared with experimental data.     

可拓学基础理论研究的新进展

简要介绍近年可拓学研究在基础理论方面的新进展，包括可拓学的框架、基元理论、可拓集合理论和可拓逻辑等所取得的成果。     

An appropriate FE model for through-thickness variation of displacement and potential in thin/moderately thick smart laminates

A finite element model for the analysis of fibre-reinforced laminated composite plates embedded and/or surface bonded with piezoelectric layers and subjected to mechanical loading and/or electric potential has been presented in this paper. The proposed model is applicable for the analysis of thin-to-moderately thick plates. No restriction has been imposed on the pattern of variation of the potential across the plate thickness so that the potential can have any value even within the core. As the plates considered here are not too thick, the structural deformation has been modelled by single layer theory where the effect of shear deformation has been taken into account following Mindlin's hypothesis. For the electric potential, layer-wise theory has been applied, as the through-thickness variation of electric potential does not follow any specific pattern. This is the first attempt wherein a combination of single layer theory and layer-wise approach has been used to solve the coupled problem of piezoelectricity in plate bending. Numerical examples have been carried out to study the performance of the proposed approach.     

Estimation of diffusion coefficients and a plausible identification of species from one-dimensional Liesegang-ring formations in multicomponent systems

Liesegang-ring phenomenon has been explained for two-component systems by many workers. In this paper an attempt has been made to extend the theory to three-component systems. It is observed that two types of rings are formed consisting of two types of species. The experimental observations verify the validity of the proposed theory. This theory can also be extended to multicomponent systems.     

Fatigue of cold worked ribbed reinforcing bar—a fracture mechanics approach

A theoretical method for the prediction of fatigue life of structural members containing external stress raisers has been developed. The method is based on a linear elastic fracture mechanics approach to fatigue. The theory has been applied to fatigue of Torbar steel in concrete beams. The required parameters for such application were obtained from fatigue tests on samples and finite element analysis of cracked bars. Comparisons between the theory and experimental data taken from other investigations have shown that the theory predicts a reasonable lower limit fatigue life of Torbar in concrete beams. The theory has also successfully predicted the effect of the minimum stress on the fatigue life of this type of bar.     

Stress intensity factor analysis for arbitrary shaped crack by local weight functions and expert systems for failure analysis

A theory has been proposed for 3D mixed mode weight function computations. This theory is based on the energy balance equation for the local perturbation of the crack front. 3D mixed mode weight functions for arbitrary loaded and shaped cracks are obtained from three reference stress intensity data. A good accuracy of the proposed technique has been demonstrated. The above approach has been applied as a background of the expert system for defects assessment analysis in structures.     

On propagation of shear waves in a multilayer medium including a fluid-saturated porous stratum

Summary The propagation of SH-type waves in a double surface layered medium with an intermediate transverse-isotropic fluid-saturated porous stratum has been examined. The top-most layer is assumed to be impermeable, elastic, homogeneous and isotropic, whereas the lower half-space is a nonhomogeneous one. The dispersion equation has been derived using the Biot's theory for the porous layer and the theory of elasticity for both the upper and the subjacent half-space.The corresponding dispersion equation for the simplified case where the dissipation caused by the relative fluid flow has been omitted has also been obtained. The numerical results obtained for this simplified case have been shown graphically.With 5 Figures     

测量不确定度与测绘学精度

测量不确定度评定理论已经是其他学科公认的测量可靠性评价规范,而测绘学科仍然一直沿用传统的精确度评价理论.通过对传统测量理论及不确定度理论核心思想原理的回顾,联系测绘生产实践中的具体事例,从概念定义、误差认识论、测量可靠性评价理念、测量仪器评价等角度,对测量不确定度理论和测绘学精度理论进行比较,指出测量不确定度和测绘学精度评定的内在联系与区别,阐明不确定度理论较传统的精确度理论的科学性和在测绘学科推广不确定度评定理论的必要性.     

Thermal conductivity of argon in the temperature range 107 to 423 K

The thermal conductivity of argon between 107 and 425 K has been measured in a transient hot-wire instrument. The results in the limit zero density have been employed to assess the accuracy of the instrument using exact kinetic theory expressions and has been found to be better than ±0.5%. The data at elevated densities are employed to examine the applicability of the modified Enskog theory in the gaseous phase and the hard-sphere theory in the liquid phase.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

Third-order theory and bang-bang control of voice coil actuators

A theory of voice coil motor actuators involving third-order differential terms in displacement that includes the inductance of the motor coil has been developed for bang-bang control time-optimal performance. Universal curves have been obtained using the theory that exhibits relationships between dimensionless quantities. The curves enable designers to choose appropriate actuator performance parameters to meet design objectives. Experimental methods have been described to determine some of the important parameters involved in the theory.     

Markets and Hierarchies and (Mathematical) Economic Theory

Over the past decade transaction-cost economics has been partiallytranslated in the more mathematical language of game theory,and understanding of the costs of transactions has been deepened,refined and extended. But the translation is incomplete: a greatdeal of human behaviour is missed, and doing game theory withmore life-like models of individuals will bring theory closerto phenomena. Transaction-cost economics, particulary the economicsof relational contracts, provides a major arena for these developments,since the important issues of bounded rationality and individualbehavior are central to the topic.     

The propagation of Love waves in a fluid-saturated porous anisotropic layer

Summary The paper concerns the propagation of Love waves in a transverse-isotropic fluid-saturated porous layer overlaying an elastic nonhomogeneous half-space. Using the Biot's theory for the porous layer and the theory of elasticity for the lower medium, the dispersion equation has been derived. This complex transcendental equation that relates frequency, phase velocity, anisotropy factor of the layer and the inhomogeneity character of the half-space has been solved with the aid of successive approximation method. The effect of anisotropy and heterogeneity has been shown graphically.With 2 Figures     

The frequency-temperature analysis equations of piezoelectric plates with Lee plate theory

Frequency-temperature analysis theory of crystal plates based on the incremental field theory (IFT) and the Mindlin plate theory have been widely used in the vibration analysis of crystal resonators subject to temperature change. As one of the two major plate theories for the resonator analysis, the Lee plate theory based on the trigonometric series expansion of displacements has been extensively used for both analytical and numerical analyses of quartz resonators, and efforts have also been made in correcting and perfecting the theory for much broader applications. In this paper, the earlier frequency-temperature analysis equations based on the IFT is further extended to the trigonometric series expansion in a systematic manner. By incorporating the frequency-temperature analysis into the Lee plate theory, the complete analysis of crystal resonators can be made in a consistent way. The thickness-shear and flexural vibration equations have been compared with the Mindlin plate theory to demonstrate the similarity and consistency.     

d电子合金理论及其在合金设计中的应用

本文介绍了近年来发展起来的d-电子合金理论及其在合金设计中的应用。该理论以分子轨道计算为基础,导出表征合金元素电子结构的基本参数后,对合金的各种行为加以合理描述。是迄今为止少数几种可用于指导实用型合金设计的理论之一。可根据实际要求设计各种具有特殊性能的合金。