Development of SPring-8 vacuum system

SPring-8 storage ring has been available for user operation with low emittance and extreme stability for over 10 years. However there occurred some problems in the components of the storage ring due to high-brightness synchrotron radiation (SR) and low-emittance operation. On the vacuum system of the storage ring, an accurate pressure could not be measured near the photon absorber due to scattered high-energy SR to the gauge head. High-energy SR activated dissolved oxygen in cooling water, and the activated dissolved oxygen corroded the inside of the photon absorbers in SR irradiation part. Air leakage occurred at an injection chamber due to impact by a small-size electron beam produced by low-emittance operation.We investigated the cause of the aforementioned difficulties with the vacuum system and prescribed the treatments described in this paper. In addition, we are making continual efforts at further system upgrades such as developing an RF shield that suppresses temperature increase in the shield in possible high-current operation.     

Morphological color changes in fish: regulation of pigment cell density and morphology

Pigment cells enable fish to change their coloration. It has been recognized that fish color changes can be divided into two categories; one is a physiological color change, which is attributed to rapid motile responses of chromatophores, and the other is a morphological color change, which results from changes in the morphology and density of chromatophores. Long-term adaptation of fish to a certain background can be a general cue to morphological color changes, and has been studied from the beginning of the 19th century. Although the motile mechanism and its control in fish chromatophores are now being elucidated, it is not yet clear how chromatophores change their density and what controls morphological color changes. In recent years, chromatophores, especially melanophores, have been shown to differentiate and to die by apoptosis under the influence of factors that regulate motile responses. Those factors are likely to utilize common intracellular signaling pathways used in part to regulate both types of color changes. In this article, after briefly reviewing the history of early studies, recent findings are discussed relevant to increases or decreases in chromatophores, and changes in their morphology. Finally, morphological color changes are discussed as physiological phenomena involved in the balance between differentiation and apoptosis of chromatophores.     

Mechanical reliability in electronic packaging

The dramatic increase in the number of devices and functionality of the latest ultra large scale integration designs have resulted in increasing chip size. Concurrently, to achieve higher circuit board component densities, package dimensions have been shrinking. These two competing trends are leading to ever more rigorous requirements on the mechanical characteristics of the packaging technology. The dominant issue in component level reliability is delamination and cracks initiated at the interface between dissimilar materials. In board level reliability, solder joint reliability is a primary issue. This paper describes the methodology of prediction and the explanation for interfacial delamination, cracks at the top of the interfaces and the edge of corner, and also solder joint reliability. This paper furthermore presents the role of the chip backside contamination affecting interfacial delamination, the surface characterizations and an explanation of the interface chemistry, and the strength of solders with a variety of plating materials for Sn–Ag-based lead free solders.     

Improvement of corrosion resistance of AZ31 Mg alloy by anodizing with co-precipitation of cerium oxide

Anodizing of AZ31 Mg alloy in NaOH solution by co-precipitation of cerium oxide was investigated. The chemical composition and phase structure of the coating film were determined via optical microscopy, SEM and XRD. The corrosion properties of the anodic film were characterized by using potentiodynamic polarization curves in 17 mmol/L NaCl and 0.1 mol/L Na₂SO₄ solution at 298 K. The corrosion resistance of AZ31 magnesium alloy is significantly improved by adding cerium oxide to alkaline solution. In addition, the surface properties are enhanced and the film contains no crack.     

Direct conversion of CO2 with diols,aminoalcohols and diamines to cyclic carbonates,cyclic carbamates and cyclic ureas using heterogeneous catalysts

CO₂ has a large effect on global warming by greenhouse gases, and development of an effective technique for the reduction of CO₂ is a crucial and urgent issue. From the chemical viewpoint, CO₂ is regarded as a stable, safe and abundant C1 resource, and the transformation of CO₂ to valuable chemicals is promising not only for reduction of CO₂ but also for production of useful chemicals. This mini‐review focuses on the direct conversion of CO₂ with diols, aminoalcohols and diamines to cyclic compounds such as cyclic carbonates, cyclic carbamates and cyclic ureas, and in particular discusses the mechanisms for these reactions over heterogeneous catalysts. © 2013 Society of Chemical Industry