Some New Exact Solutions to the Dispersive Long－Wave Equation in（2＋1）－Dimensional Spaces

In this paper, by using a further extended tanh method- and symbolic computation system, some new soliton-like and period form solutions of the dispersive long-wave equation in (2+l )-dimensional spaces are obtained.

Improvement of Prediction Method for Strip Coiling Temperature

In order to improve the control precision of strip coiling temperature for hot strip mill,the BP neural network was combined with mathematical model to calculate convective heat-transfer coefficient of laminar flow cooling.The off-line calculated results indicate that the standard deviation of coiling temperature prediction is reduced by 22.84 % with the convective heat-transfer coefficient calculated by BP neural network.The prospects of this method for online application are bright.This method is more helpful to increasing the control precision of coiling temperature for hot strip steel.

Hot Deformation Behavior of an As-cast Duplex Stainless Steel

The hot deformation behavior of an as-cast OCrl7Mnl4Mo2N duplex stainless steel has been studied by hot compression test at the temperature range from 1000℃ to 1200℃, and the strain rates are 0.1 s-1, 1 s-1 and 5 s-1, respectively. It was found that during hot deformation there is only dynamic recovery taking place within the δ-ferrite phase, but the γ-austenite phase undergoes dynamic recrystallization. The activation energy of the steel for hot compression is estimated to be 480 kJ/mol.

Numerical Simulation of Dendrite Evolution during Solidification Process

The effect of manganese on the as-cast structure and hardening behavior of high chromium white cast iron subjected to sub-critical treatment was studied. The results indicate that the fraction of retained austenite and the manganese distribution in as-cast alloys are controlled by manganese content. The manganese distribution in as-cast alloys is not homogeneous. The manganese content in carbide is higher than that in matrix. Whether the secondary hardening occurs or not and the peak hardness of secondary hardening is controlled by manganese content in retained austenite in as-cast structure. Higher manganese content can cause more retained austenite. The secondary hardening occurs in sub-critical treating process if the fraction of retained austenite is high.

Molecular Simulation of Hydrogen Adsorption Density in Single-Walled Carbon Nanotubes and Multilayer Adsorption Mechanism

The adsorption of hydrogen onto single-walled carbon nanotubes (SWCNTs) was studied by molecular dynamics (MD) sim'lation. It was found that the hydrogen molecules distribute regularly inside and outside of the tube. Density distribution was computed for H2 molecule. Theoretical analysis of the result showed the multilayer adsorption mechanism of SWCNTs. The storage of H2 in SWCNTs is computed, which provides essential theoretical reference for further study of hydrogen adsorption in SWCNTs.

Effect of Cd and Sn Addition on the Microstructure and Mechanical Properties of AI-Si-Cu-Mg Cast Alloy

The present work has investigated the effect of trace elements Cd and Sn on the microstructure and mechanical properties of Al-Si-Cu-Mg cast alloy. With the increase of Cd addition the strength of alloy rises at first and then drops. The optimal amount of Cd and Sn addition for Al-Si-Cu-Mg alloy is about 0.27% and 0.1% respectively. Due to the formation of some coarse Cd-rich phases and pure Cd particles the mechanical properties of alloy decrease when Cd amount exceeds 0.27%. When more than 0.1% Sn added, some Sn atoms form low-melting eutectic compound at grain boundary, and then cause over-burning in alloy when solution treated, which may deteriorate properties of alloy, especially ductility of alloy. On the other hand, the addition of Cd and Sn remarkably increases the peak hardness and reduces the time to reach aging peak in Al-Si-Cu-Mg alloy. The action of Cd /Sn in quaternary Al-Si-Cu-Mg alloy is effectively the same as that occur in binary Al-Cu alloy that the enhanced hardening associated with Cd / Sn addition is due to the promotion of the 6’ phase.

H_∞ Optimal Model Reduction for Singular Fast Subsystems

In this paper, H∞ optimal model reduction for singular fast subsystems will be inves-tigated. First, error system is established to measure the error magnitude between the original andreduced systems, and it is demonstrated that the new feature for model reduction of singular systemsis to make H∞ norm of the error system finite and minimal. The necessary and su?cient conditionis derived for the existence of the H∞ suboptimal model reduction problem. Next, we give an exactand practicable algorithm to get the parameters of the reduced subsystems by applying the matrixtheory. Meanwhile, the reduced system may be also impulsive. The advantages of the proposedalgorithm are that it is more ?exible in a straight-forward way without much extra computation, andthe order of the reduced systems is as minimal as possible. Finally, one illustrative example is givento illustrate the e?ectiveness of the proposed model reduction approach.

Effects of Biaxial Crystal-Field on Magnetic System

The spin-1 Ising model with biaxiM crystal-field on the honeycomb lattice is investigated by using the effective-field theory with self-spin correlations and the differential operator technique. The effects of biaxial crystal-field described by two uniaxial anisotropy parameters Dx and Dy on the phase transition and specific heat and susceptibility are studied numerically. Some interesting results are observed in the system such as tricritical behavior depending sensitively on the strength of the biaxial crvstal-field.

Application of General Fractal Dimension to Coupling Fault Diagnosis

This paper presents the coucept of general and sensitive dimension, and also proposes the calculation formula of the general dimension least squares method. By calculating and analyzing the power spectrum and general dimension from the fault sample, the relationship is achieved between sample status and the general dimension from vibration signals of the equipment so as to provide reference to fault diagnosis. Furthermore, a correlation function of general dimension is proposed, and calculations are carried out for a monitor signal and samples signal. The diagnosis method based on fractal theory is effective through the concrete examples of the steam electric generating set fault diagnosis, and the correlation coefficient of general dimension between a monitor signal and samples signal can improve the accuracy for fault diagnosis.

Phase Transition for a Mixed Spin-1／2 and Spin-sB System with a Transverse CrystalField

The critical behaviors of a mixed spin-1/2 and spin-sB Ising system with a transverse crystal field are studiedby use of the effective-field theory with correlations. The effect of the transverse crystal field on transition temperaturesis investigated numerically for the honeycomb (z = 3) and square (z = 4) lattices. The results show that there is notricritical point for the system.

Properties of Three Pseudo-Spins in Ferroelectric or Ferro-Antiferroelectric Materials Described by a Transverse Ising Model

Ferroelectric phase diagrams and the temperature dependence of polarization, dielectric properties of the three pseudo-spin in ferroelectric or ferro-antiferroelectric system described by a transverse Ising models are investigated on the basis of the effective-field theory with the differential operator technique. The effects of the transverse field and the coupling strength between the nearest-neighboring pseudo-spin on the physical properties are discussed in detail.

STUDY ON ELEVATED TEMPERA-TURE MECHANICAL PROPERTIES OF AM50HP WITH ND

Effects of Nd on the mechanical properties of die casting magnesium alloysAM50 are investigated. It is found that the ultimate tensile strength, yield strength and elongationof the AM50 alloy at elevated temperatures up to 200 deg C increase with an addition of Nd.Generally, the most significant improvement in the tensile properties is attained at 100 deg C. Thepresence of Mg12Nd is proved by X-ray diffraction. Microstructural observations reveal that theaddition of Nd can lead to the dispersion-strengthening. Due to the presence of Mg12Nd, the slidingof grain boundaries is restrained and the strength of the alloy is enhanced. It can be seen from thetensile fractographs that the fracture surfaces exhibit the mixed fracture characteristics, andless brittle fracture is observed with increasing the temperature. Quasi-cleavage fracture isthought as the main fracture mode. TEM observations expose the formation of dislocation network,slip lines and dislocation pile-ups.

Reliable routing algorithm in marine ad hoc networks

A routing algorithm called DNH for increasing efficiency of mobile ad hoc network is presented, which is based on a new criterion called TSS ( Temporarily Steady State) , combining with wireless transmission theory that makes networks topology correspondingly stabilization. Also the DNH algorithm has the characteristics of giving up queuing in a node, but selecting another idle node instead of the node for forwarding data packets if the node has a full throughput. Simulation evaluation shows that selecting another node is better than queuing in a full throughout node if some conditions are satisfied, especially during a sea battle, every warship in ad hoc network wants to contest time and increase propagation reliability. The DNH algorithm can help decrease routing time, and raise efficiency of marine ad hoc networks.

Numerical scheme for elastoplastic parameter identification and finite element analysis of wall-slope of the Fushun West Open Pit Mine

The elasto brittle plastic finite element analysis has been taken on the prediction for the deformation of the northwall of an open pit of Fushun, China. Numerical simulation has been made on the reinforcement measures of the slope structure. Using parameter identification techniques and connecting with elasto brittle plastic finite element program, the displacement back analysis has been made on the material parameters of the rockslope. The equivalent parameter values of the real slope structure have been obtained. The process of the rapid increment of the slope′s deformation caused by open mining during 1987～1990 has been reappeared through the numerical simulation.

Expert Diagnosing System for a Rotation Mechanism Based on a Neural Network

By combining the artificial neural network with the rule reasoning expert system, an expert diagnosing system for a rotation mechanism was established. This expert system takes advantage of both a neural network and a rule reasoning expert system; it can also make use of all kinds of knowledge in the repository to diagnose the fault with the positive and negative mixing reasoning mode. The binary system was adopted to denote all kinds of fault in a rotation mechanism. The neural networks were trained with a random parallel algorithm (Alopex). The expert system overcomes the self learning difficulty of the rule reasoning expert system and the shortcoming of poor system control of the neural network. The expert system developed in this paper has powerful diagnosing ability.