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The oxidation of six Cu-xNi alloys (x = 0.2, 0.6, 1, 2, 3, 4 at.%) was studied at 800 °C under 1 atm O2. All of the binary Cu-Ni alloys underwent an internal oxidation of Ni in the presence of an external scale of Cu2O and CuO, in agreement with the theoretical expectations for a finite range of Ni contents. However, the behavior of internal oxidation deviates significantly from the classical behavior of internal oxidation described by Wagner, in particular for the absence of a well-defined front of internal oxidation.

FePt nanoparticles with uniform compositions were synthesized by a modified coreduction process of FeCl2·4H2O and Pt(acac)2and then rapidly annealed in a vacuum under temperatures ranging from 500 to 700 °C. We found that the coercivities of the FePt nanoparticles were greatly enhanced by the rapid annealing in a vacuum. Negative peaks on δMcurves for the annealed FePt nanoparticles demonstrate that the predominant interparticle interactions are dipolar-type rather than exchange coupling ones, which indicates that the rapid annealing in a vacuum can prevent the agglomeration of the nanoparticles. Through the heat treatment of annealing in a vacuum, monodispersed Fe46Pt54nanoparticles with a high coercivity of 9230 Oe were successfully fabricated.

It is well known that non-periodic behavior is one of the most puzzling characteristics of chaotic oscillators. So far chaotic dynamical systems have been investigated in Euclidean spaces. In this paper, the concept of non-autonomous dynamical systems and that of Hausdorff phase spaces are proposed. The behavior of chaotic impact oscillators is investigated in Hausdorff phase spaces. It is discovered that, although the non-autonomous dynamical systems described by chaotic impact oscillators are non-periodic in Euclidean phase spaces, they are periodic in Hausdorff phase spaces. This shows that Euclidean spaces in which we stayed for hundreds of years may no longer be suitable for the investigation into chaotic phenomena. In addition, the periodicity of chaotic dynamical systems in Hausdorff metric spaces induces a new class of strange invariant sets in Euclidean spaces. Such strange invariant sets may be an ideal symbol of chaotic dynamical systems.

A simple and effective procedure for conducting the free vibration test on highway bridges is presented. The impulsive force in each direction is generated by a loaded truck that either stops suddenly or falls down from a rigid block. The feasibility of the procedure is demonstrated in identification of the dynamic properties, i.e. the vibration frequencies, mode shapes, and damping ratios, of a three-span box-girder concrete bridge using the Ibrahim Time-Domain (ITD) technique. Up to 14 modes have been identified for the present case. For the purpose of verification, ambient vibration tests were also carried out, with the data processed by the random decrement (Randomdec) technique to yield the free vibration response, followed by the ITD technique. The dynamic properties identified from the two types of test correlate very well with each other, indicating the validity of each procedure described herein. Although many more modes can be identified from the free vibration test because of the higher quality of data produced, the easiness and general applicability of the ambient vibration test can still be appreciated. A comparison of the experimental results with those by the finite element method indicated a lesser degree of correlation, implying that the finite element model adopted in design requires further refinement, say, through a more realistic evaluation of the boundary conditions, geometric and material properties of the bridge. Copyright © 1999 John Wiley & Sons Ltd.

The authors describe a patient with primary Sjögren's syndrome who developed pachymeningitis, hypopituitarism, and central diabetes insipidus. The patient improved with corticosteroid pulse therapy.

A fast and storage‐efficient algorithm for the computation of the static response of determinate trusses to nodal loading is proposed. In terms of the number of bars in the truss, M; the algorithm is of computational complexity O(M2) and requires only O(M) primary storage, for M linearly independent loadings. The motivation to develop a fast algorithm stems from the need for such an algorithm in the fast and efficient control of adaptive space cranes. The algorithm is based on the well‐known method of joints. Although the traditional method of joints computes response only for simple determinate trusses, the algorithm includes the extension for the compound and complex determinate trusses by generalizing the Henneberg method. It has been coded in FORTRAN77 into a computer program called DETRANS (Determinate Truss Analysis System). The theoretical basis of the algorithm, the data structures used in the program, and the computational complexity analysis are given.

The dynamic behaviour of a single degree-of-freedom (DOF) equipment mounted on a sliding primary structures subjected to harmonic and earthquake ground motions is studied numerically. To deal with the discontinuity nature of sliding structural systems, in this work the fictitious spring model is adopted. With the problem formulated in a state space form, an incremental numerical scheme capable of dealing with multi-DOF sliding structural systems is proposed for solving the time history responses. Numerical examples excited by harmonic and real earthquake ground motions are considered in order to study the following three effects: (1)the variation of the frictional coefficient of the sliding support, (2)subharmonic resonance and (3)effect of tuning (i.e. when the frequency of the equipment is coincident with or close to the fundamental frequency of the primary structure) on the mounted equipment. The dynamic characteristics of the mounted equipment are highlighted in the analysis of the numerical examples. © 1997 by John Wiley & Sons, Ltd.