济钢高炉喷煤数学模型的研究与应用

基于湍流两相流理论建立了高炉喷煤两相流动及传质三维数学模型。采用该模型指导高炉生产 ,高炉利用系数由2 .7t/(m3.d)提高到 3 .0 t/(m3.d)以上 ,焦比由 460 kg/t降到 40 0 kg/t,煤比达到 10 0 kg/t,提高了高炉的各项经济技术指标。     

丁集矿副井井架基础沉降变形分析

按井筒冻结施工的进度,选择合适的周期进行沉降变形观测,根据大量的实测资料对冻结施工前后丁集矿副井井架基础的沉降变形规律进行了分析,并预测其沉降变形趋势。     

RMT1-250转换开关用电接触材料

铜铬锆合金是一种形变热处理材料，兼具了铜铬合金和铜锆合金的各种优良性能，经过时效处理的铜铬锆合金，与铜相比，高温强度有很大的改善，而且具有较高的导电率。所以铜铬锆合金广泛应用于电焊机、低压电器等行业。根据对铜铬锆成分的适当调整，可用作为电焊机电极，低压电器触桥、短路环等各种电接触材料。铜铬锆合金用于RMT1－250转换开关，接近于触桥材料的应用，但使用的条件更苛刻一些，要承受部分电弧的侵蚀和由此产生的高温，因此对材料要求具有良好的导电导热性和更高的高温强度。     

Structural Changes in Titin and Nebulin Filaments Specific to Calcium Ions at 0.1 mM: Factors of Meat Tenderization During Postmortem Aging

ABSTRACT Postmortem structural changes in titin and nebulin filaments were investigated by incubating isolated myofibrils in a solution containing 0.1 mM calcium ions and various concentrations of a protease inhibitor. The inhibition curves showed 2 abnormal steps with increases in the concentration of leupeptin or calpastatin domain I. While the amounts of unchanged titin and nebulin were constant in the 1st step, the 2nd occurred at higher protease inhibitor concentrations. These facts indicated that excess amounts of leupeptin and calpastatin domain I caused deterioration in titin and nebulin properties, thus interfering with the binding of calcium ions. We concluded that the severance of titin and nebulin filaments in the 1st step were induced by calcium ions at 0.1 mM.     

无源性理论在永磁同步电动机混沌控制中的应用

永磁同步电动机在一定的工作条件下呈现出混沌运动，根据无源性网络理论，设计电动机混沌动力学模型的控制器，将混沌系统等效为无源系统，消除系统中的混沌运动，降低系统自激振动的危害，实现混沌系统的快速稳定。     

A family of lower- and higher-order transversal linearization techniques in non-linear stochastic engineering dynamics

Sample pathwise numerical integration of noise-driven engineering dynamical systems cannot generally be performed beyond a limited level of accuracy, especially when the noise processes are modelled using (filtered) white noises. Recently, a locally transversal linearization (LTL) strategy has been proposed by the author (Proc Roy Soc London A 2001; 457 :539–566) for direct integration of deterministic and stochastic non-linear dynamical systems. The present effort is focussed on a host of extensions along with detailed theoretical error analyses of the linearization approach, especially as applied to problems in non-linear stochastic engineering dynamics. Thus, to begin with, estimates of local and global error orders in the basic LTL scheme are obtained separately for the displacement and velocity vectors when the system is driven either by a set of additive noises or by an arbitrary combination of (independently evolving) additive and multiplicative noises. Following this, a new family of higher-order LTL schemes is proposed in order to improve upon the basic LTL method and the associated error orders are established. A stepwise implementation of the lower- and higher-order versions of the LTL method, along with certain computational aspects, is also outlined. The proposed schemes are numerically illustrated, to a limited extent, for a single degree-of-freedom (SDOF) and a two degree-of-freedom (TDOF) non-linear engineering systems under additive and/or multiplicative white noise excitations. Copyright © 2004 John Wiley & Sons, Ltd.     

Updated semi‐discretization method for periodic delay‐differential equations with discrete delay

An updated version of the semi‐discretization method is presented for periodic systems with a single discrete time delay. The delayed term is approximated as a weighted sum of two neighbouring discrete delayed state values and the transition matrix over a single period is determined. Stability charts are constructed for the damped and delayed Mathieu equation for different time‐period/time‐delay ratios. The convergence of the method is investigated by examples. Stability charts are constructed for 1 and 2 degree of freedom milling models. The codes of the algorithm are also attached in the appendix. Copyright © 2004 John Wiley & Sons, Ltd.     

Stability of Circular Cylindrical Shells with a Single Local Dent

The theoretical-and-experimental investigation has been performed on the stability of smooth cylindrical shells of steel with a single local dent. All the shells manufactured using the same process were tested with the fulfillment of identical conditions for observations and measurements. Theoretical calculations were carried out by the mesh method with the use of the nonlinear theory of shells. A comparison of the experimental and theoretical values of the critical loads has been made. The theoretical-and-experimental approach proposed enables one to evaluate the quality of shells by studying local dents and other specific imperfections.