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Microstructure evolution of Ni-based oxide dispersion-strengthened alloy powders with milling time is investigated. The elemental powders having a nominal composition of Ni-15Cr-4.5Al-4W-2.5Ti-2Mo-2Ta-0.15Zr-1.1Y2O3 in wt % were ball-milled by using horizontal rotary ball milling with the change of milling velocity. Microstructure observation revealed that large aggregates were formed in the early stages of ball milling, and further milling to 5 h decreased particle size. The average crystalline size, estimated by the peak broadening of XRD, decreased from 28 nm to 15 nm with increasing milling time from 1 h to 5 h. SEM and EPMA analysis showed that the main elements of Ni and Cr were homogeneously distributed inside the powders after ball milling of 5 h.

Chalcogenide glass in the ternary Ge-Sb-Se system is inherently moldable, thus being considered as a strong candidate material for use in infrared-transmitting lens applications from the viewpoint of thermal and mechanical stability. In an effort to experimentally determine compositional region suitable for the molded lens applications, we evaluate its compositional dependence of hardness. Among the constituent atoms, Ge content turns out to exert a most conspicuous correlation with hardness. This phenomenological behavior is then explained in connection with the structural evolution that Ge brings about.

The effect of carbon mixing on the perpendicular magnetization of magnetron sputtered FePt thin films on our newly developed underlayer of Pt/MgO(p) composite thin-film was studied using magnetic property measurement and X-ray diffraction, and TEM microscopy. Micromagnetic simulation was carried out to study the effect of texture on the perpendicular coercivity. Unlike a general expectation, the mixing of FePt with carbon led to a significant enhancement in the perpendicular magnetization. The maximum enhancement of perpendicular magnetization was observed at about 22 vol.% of carbon, where carbon amorphous film started to completely enclose the individual FePt grains. This was because the epitaxial growth and thus perpendicular texture of ordered FePt grains were maximized in the isolated grain structure due to a maximum relaxation of coherency strain for epitaxial growth. The simulation showed that the enhancement of perpendicular texture can largely increase the perpendicular coercivity of FePt:C thin film. Index Terms--Epitaxial growth, FePt:C magnetic thin films, perpendicular magnetization, texture.

Engine knocking and misfire cause a negative effect on the engine power and the exhaust emissions such as HC, CO and N[O.sub.x]. They also cause permanent damages to the three way catalyst (TWC) system. And a heavy knock can cause severe damages to the engine itself, which gives more reason why it must be detected and corrected. This study introduces a new system concept for detecting combustion misfire and knocking using breakdown voltage (BDV) characteristics between spark plug electrodes. This system detects and evaluates the degree of combustion by measuring the breakdown voltage which predicts that the breakdown voltage depends on the pressure and the temperature.

In the case of mechanical structures joined by bolts and nuts, many studies have been conducted on the stiffness of the joined members. Accordingly, an appropriate formula for this case has already been formulated and verified by experimentation. However, the case of joined members with a sleeve, which is a common situation in civil engineering, has not yet been considered. Consequently, an elastic closed-form solution is derived for evaluating the stiffness of bolted-joint members with a sleeve, the material of which is different from the joined members. The proposed formula is then verified by an experiment and finite element method. And then it is used to calculate member stiffness in a concrete structure. The results confirm that the proposed formula can be effectively used to calculate the stiffness of joined members with a sleeve, particularly when predicting the fatigue failure of a bolt under fluctuating loads. DOI: 10.1061/(ASCE)0733-9445(2002)128:7(951) CE Database keywords: Stiffness; Bolted joints; Finite element method.