NETE (United States)

Cocitation measurements can reveal the extent to which a concept representing a novel combination of existing ideas evolves towards a specialty. The strength of cocitation is represented by its frequency, which accumulates over time. Of interest is whether underlying features associated with the strength of cocitation can be identified. We use the proximal citation network for a given pair of articles ( x, y) to compute θ, an a priori estimate of the probability of cocitation between x and y, prior to their first cocitation. Thus, low values for θ reflect pairs of articles for which cocitation is presumed less likely. We observe that cocitation frequencies are a composite of power-law and lognormal distributions, and that very high cocitation frequencies are more likely to be composed of pairs with low values of θ, reflecting the impact of a novel combination of ideas. Furthermore, we note that the occurrence of a direct citation between two members of a cocited pair increases with cocitation frequency. Finally, we identify cases of frequently cocited publications that accumulate cocitations after an extended period of dormancy.

We developed a new surface treatment system, a vacuum atmospheric-controlled induction heating fine particle peening (AIH-FPP) treatment system. The system is able to shoot fine particles at high speed in a controlled atmosphere with less than 10 ppm of oxygen concentrations. In the treatment, the substrate is heated to higher temperature by high frequency induction heating. In order to investigate the effects of treatment temperature and shot of mixed particles of Chromium (Cr) and high speed steel (AISI M42) on the formation of the surface modified layer, carbon steel was treated by vacuum AIH-FPP treatment using Cr particles and mixed shot particles of Cr and AISI M42 (Cr75, 50 and 25 mass%) at 800℃ and 1000℃ in nitrogen atmosphere. The surface modified layer was characterized by a scanning electron micro scope (SEM) and an energy dispersive X-ray spectrometer (EDX). In the case of the specimen treated with mixed shot particles of Cr and AISI M42 (Cr50 and 25 mass%) at 1000℃, a Cr diffused layer was formed at the surface. This was because the diffusion of Cr was accelerated by higher temperature and using mixed shot particles of Cr and AISI M42. Moreover, we revealed that the increase in flow velocity at the point of FPP nozzle accelerated the transfer of Cr.

To clarify the effects of Super Rapid Induction Heating and Quenching (SRIHQ) on fatigue properties of Ferritic Ductile Cast Iron (FDI), rotational bending fatigue tests were carried out on specimens treated with four types of heating cycle. Results showed that; (i) the SRIHQ process generated a thin dark gray area around the graphite. This dark area was composed of a martensite structure (ringed martensite). (ii) The ringed martensite generated a compressive residual stress field at the surface hardened layer. Two types of compressive residual stress generative mechanisms were observed. One was a microscopic residual stress generative process due to the formation of ringed martensite and the other was a macroscopic residual stress generative process due to the expansion of the surface hardened layer. (iii) The fatigue strength of SRIHQ treated FDI specimen was higher than that of the untreated one. This was because the compressive residual stress field generated by the ringed martensite suppressed initiation and propagation of fatigue cracks.