Nickel/Zinc Chloride‐Promoted Domino Reaction of Enynes and Enones Including Unstrained C?C Bond Cleavage

Unstrained C C bond cleavage proceeds during the domino reaction of enynes and enones that includes successive C C bond formation under the nickel/zinc/zinc chloride system. The cleavage occurs through β‐syn‐elimination of the 1,3‐dicarbonyl part. In addition, β‐carbon elimination is selective, unlike the β‐hydrogen elimination in the presence of excess zinc chloride.     

Inverse halftoning using super‐resolution image processing

This paper focuses on the inverse halftoning problem, that is, the problem of reconstructing continuous‐tone images from halftone images of white and black pixels. In general, the problem does not have a unique solution, since halftoning is a many‐to‐one map from continuous‐tone images to binary ones. To this problem, we provide a simple and useful inverse halftoning method, composed of two steps. The first step is to generate several grayscale images from the original halftone image and low‐pass filters. The next step is to reconstruct a continuous‐tone image from the multiple grayscale images by using super‐resolution image processing. This method allows us to obtain good continuous‐tone images which are comparable to the results of the existing methods. The validity of the proposed method is demonstrated by several experiments. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Optical timing distribution system with femtosecond stability

Stable timing distribution is a key technology for the many fields that use timing signals for synchronization. The frequency of the timing signal depends on the field and multiple timing signals are sometimes required. In our DWDM‐based timing distribution system, phase deviation is detected by high‐speed round‐trip signal (10 GHz signal is used as this control signal). Fiber stretchers are controlled so as to minimize the phase deviation of the control signal. Multiple signals and the control signal are densely multiplexed and transmitted through the same stretchers. Therefore, the transmission of all signals is stabilized. This configuration provides a flexible platform for distributing various RF or microwave signals. As an example of arbitrary timing signals, a 1 GHz signal is transmitted over a length‐stabilized 400‐m fiber for more than 1 day. The recorded propagation time fluctuations are 10.4 and 2.8 fs rms for the 1 and 10 GHz signals, respectively. The Allan deviations are 2.7 × 10⁻¹⁹ (1 GHz) and 6.0 × 10⁻²⁰ (10 GHz) for the averaging time of 10⁵ s. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Polymerized ionic liquids with guanidinium cations as host for gel polymer electrolytes in lithium metal batteries

Polymerized ionic liquids (PILs) having guanidinium cations with different counter‐anions, such as PF₆^? and N(CF₃SO₂)₂^? (TFSI^?), were synthesized by copolymerization of a guanidinium ionic liquid monomer with methyl acrylate followed by an anion exchange reaction. Furthermore, incorporating a guanidinium ionic liquid, LiTFSI salt and nano‐size SiO₂, a quaternary gel polymer electrolyte based on one of the PILs as the polymer host was prepared. The quaternary gel polymer electrolyte was chemically stable even at a higher temperature of 80 °C in contact with the lithium anode. In particular, the electrolyte exhibited high lithium ion conductivity, wide electrochemical stability window and good lithium stripping/plating performance. Li/LiFePO₄ batteries with the quaternary gel polymer electrolyte at 80 °C had capacities of 140 and 130 mA h g^?1 respectively at 0.1 and 0.2 C current rates. Copyright © 2011 Society of Chemical Industry     

Hydrogen embrittlement behavior induced by dynamic martensite transformation of Ni–Ti superelastic alloy

The hydrogen embrittlement behavior induced by the martensite transformation of Ni–Ti superelastic alloy subjected to a dynamic cyclic tensile test with hydrogen cathodic charging has been investigated by hydrogen thermal desorption analysis. The critical stress for the martensite transformation steeply decreases with increasing number of deformation cycles, whereas the critical stress for the reverse transformation only slightly changes. The dynamic stress-induced martensite transformation markedly enhances hydrogen absorption, compared with that of the martensite phase itself. The hydrogen concentration at the surface layer of the specimen is evaluated to be above 3500 mass ppm; nevertheless, no fracture associated with the stress-induced martensite transformation occurs. In addition, no hardening is observed at the surface layer of the specimen despite the formation of the hydride and hydrogen enrichment. The hydrogen thermally desorbed at a low temperature markedly increases, indicating that the hydrogen states are changed by the dynamic martensite transformation. Note that interactions between hydrogen and the phase transformation are probably irreversible, although the phase transformation is reversible. The present study shows, for the first time, that the hydrogen embrittlement behavior of the alloy strongly depends on the dynamic change of the hydrogen states accompanied by the martensite transformation.     

Sliding wear behaviour of some Fe-, Co- and Ni-based metallic glasses during rubbing against bearing steel

The sliding wear behaviour of several compositions of Fe-, Co- and Ni-based metallic glasses have been studied while rubbing against AISI 52100 bearing steel under reciprocating-sliding conditions. The wear resistances of Fe-based metallic glasses and Ni-based metallic glass (MBF 50) have been found to be superior to that of the mating AISI 52100 bearing steel. The examination of worn surfaces indicates that the superior wear resistance of metallic glasses is not merely owing to their high hardness but it is determined by phenomena of material transfer vis-à-vis the mating material and the formation of protective oxide layers on the metallic-glass surface during sliding. This revised version was published online in August 2006 with corrections to the Cover Date.     

Countering the Segregation of Transition‐Metal Ions in LiMn1/3Co1/3Ni1/3O2 Cathode for Ultralong Life and High‐Energy Li‐Ion Batteries

High‐voltage layered lithium transition‐metal oxides are very promising cathodes for high‐energy Li‐ion batteries. However, these materials often suffer from a fast degradation of cycling stability due to structural evolutions. It seriously impedes the large‐scale application of layered lithium transition‐metal oxides. In this work, an ultralong life LiMn_1/3Co_1/3Ni_1/3O₂ microspherical cathode is prepared by constructing an Mn‐rich surface. Its capacity retention ratio at 700 mA g^?1 is as large as 92.9% after 600 cycles. The energy dispersive X‐ray maps of electrodes after numerous cycles demonstrate that the ultralong life of the as‐prepared cathode is attributed to the mitigation of TM‐ions segregation. Additionally, it is discovered that layered lithium transition‐metal oxide cathodes with an Mn‐rich surface can mitigate the segregation of TM ions and the corrosion of active materials. This study provides a new strategy to counter the segregation of TM ions in layered lithium transition‐metal oxides and will help to the design and development of high‐energy cathodes with ultralong life.