Microstructure development of steel during severe plastic deformation

The microstructure development during plastic deformation was reviewed for iron and steel which were subjected to cold rolling or mechanical milling (MM) treatment, and the change in strengthening mechanism caused by the severe plastic deformation (SPD) was also discussed in terms of ultra grain refinement behavior. The microstructure of cold-rolled iron is characterized by a typical dislocation cell structure, where the strength can be explained by dislocation strengthening. It was confirmed that the increase in dislocation density by cold working is limited at 10¹⁶m⁻², which means the maximum hardness obtained by dislocation strengthening is HV3.7 GPa. However, the iron is abnormally work-hardened over the maximum dislocation strengthening by SPD of MM because of the ultra grain refinement caused by the SPD. In addition, impurity of carbon plays an important role in such grain refinement: the carbon addition leads to the formation of nano-crystallized structure in iron.     

等温淬火温度对奥贝球铁水脆化行为的影响

研究了等温淬火温度对奥贝球铁(ADI)水脆化行为的影响，水附着条件下不同等温淬火温度处理的ADI均发生水脆化行为，抗拉强度和伸长率显著降低；但随着等温淬火温度升高，ADI的水脆化程度降低。高强度的ADI、淬火回火球铁和珠光体球铁均发生水脆化行为，而铁素体含量高的铸态球铁和铁素体球铁无明显的水脆化行为。     

A superconducting filter to separate an oxygen and argon mixture

Hot isostatic pressing in an oxygen atmosphere, known as O₂-HIP method, has been used successfully to synthesize oxide materials, as well as to produce porous materials. In this paper a porous superconducting oxide is synthesized by this method and its application as a gas filter is described. Porous superconductors can be used to separate a mixture of paramagnetic and diamagnetic gases, such as oxygen and argon. Separation occurs after a magnetic field is applied and is based on the Meissner effect. Experimental results showed that the oxygen content of an oxygen/argon mixture increased after passing through a filter with large pore size (about 10 m).     

Effect of a dynamic absorber on friction-induced vibration of a rectangular plate

When a plate-like object is rubbed by rubber, friction-induced vibration is generated. To reduce the friction-induced vibration, we experimentally investigate the characteristics of the vibration of a rectangular glass plate. The results show that the frequency of the friction-induced vibration is almost the same as the natural frequency of a glass plate. The vibration is generated when the natural frequency of a rubbing system is close to that of a glass plate. We then examine the effect of a dynamic absorber mounted on the glass plate. The results demonstrate that the damping of a dynamic absorber is effective for suppressing the friction-induced vibration. Numerical simulation is also performed using a simplified analytical model. The calculated results agree qualitatively with the experimental ones.     

The separation of fission-product rare elements toward bridging the nuclear and soft energy systems

Based on the present state of the art of the separation technology, recycling of fission-product rare elements (FRE) in the FBR spent fuel is discussed. The rad.-waste fractionation is in accordance with the present society's trend toward zero-emission, and the mean of salt-free method utilizing electrochemistry agrees with the principles of the newly established green chemistry. A catalytic electrolytic extraction method is proposed to separate the target, radioactive but potentially strategic elements, Pd, Ru, Rh, Re (Tc), Te and Se dissolved in the HLLW. It avoids secondary waste arising. This method is particularly feasible for the separation of Pd where cyclic reaction of metal cations such as Pd(II) or Fe(II), acting as promoters or mediators and already contained in HLLW, accelerates the electrochemical deposition of Ru, Rh and Re. Elemental separation not only offers alternative material resources to meet expanding demands for catalysts in Fuel Cell/Soft Energy system but is also the first step for transmutation or other selective strategies for waste management of long-lived fission products (LLFP).     

Photon-induced phonon excitation process as low-temperature nonequillibrium nano-surface modification of silicon

A novel technique to achieve non-thermal annealing of implanted semiconductor dopants is proposed on the basis of photon-induced phonon excitation process as low-temperature nano-surface modification of semiconductors. The present approach is based on the concept that the energy required for re-crystallization and activation of the dopants is supplied to the dopant layer via nonequillibrium adiabatic process induced by ultra-short pulse laser irradiation at room temperature. Ultra-short pulse laser beam with a pulse duration of 100 fs has been used in the present study for investigations on phonon excitation features via pump-probe measurement of reflectivity and for demonstration of room-temperature re-crystallization and activation of ion-implanted silicon substrates.     

Challenges to the Carbon Dioxide Capture and Storage (CCS) Technology

Carbon dioxide Capture and Storage (CCS) technology, which is one of the technologies against global warming, applied to the separation and capture of CO₂ gas and finally storage underground is attracting attention. There are several technologies being developed for CO₂ separation and capture, namely the chemical absorption method, physical absorption method, adsorbing separation method and membrane separation method. These are being developed to apply to postcombustion capture, oxyfuel postcombustion capture, etc. With regard to the CO₂ storage technologies, the method of injection into an aquifer is being developed as the major one, and studies on issues for actual technical application are being conducted in the form of engineering study on the assumed model area. In this report, our expectations toward actual application of the CCS technology, the trends of the CCS technology and other related matters are introduced. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Analysis of Largest Sulfide Inclusions in Low Carbon Steel by Using Statistics of Extreme Values

The statistics of extreme values was applied for the determination of the largest sulfide inclusions with different morphology in low carbon steel samples by using both two‐dimensional (2D) observations on the polished cross section and three‐dimensional (3D) observations on a surface of a film filter after electrolytic extraction of the samples. It was found that the globular, rod‐like and dendritic sulfides in the molten steel sample as well as the elongated sulfides in the rolled steel sample can be successfully extracted from the both samples, and analyzed precisely by using extreme value analysis in 3D. Based on the geometrical considerations of the probability for measurement of the true length of rod‐like and elongated inclusions on a cross section, it was found that this probability for inclusions decreases dramatically with an increasing real aspect ratio value of them. Particularly for the determination of the true length for elongated inclusions in the rolled steel sample by 2D investigations on a metal cross section, it is required to be cut investigating section of steel sample within ± 1 degree against rolling direction. Therefore, a 3D observation is considered to be more preferable and accurate than the conventional cross sectional observation in 2D, due to the possibility for the measurements of the real size of them.     

Human-sized anthropomorphic robot hand with detachable mechanism at the wrist

In this paper, we proposed a human-sized multi-fingered robot hand with detachable mechanism at the wrist. The fingers are tendon-driven by wires and the actuators are embedded in the arm part. The driving forces from the arm part are transmitted to the hand part by a gear mechanism at the wrist. The gear mechanism makes the hand part and the arm part splittable. The detachable mechanism enables separate maintenance of the hand and arm parts. To avoid undesired joint mutual interferences due to the tendon-driven mechanism, a joint motion correction control is implemented in that counteracting motions are ordered to actuators. The correction coefficient can be calculated based on the mechanical configuration. The developed robot hand has the size of 200[mm](length) × 78[mm](width) × 24.6[mm](thickness) and can exert 10[N] at the fingertip. The performance of the developed robot hand was shown by a motion control experiment.