Novel seed for batch cold seeding production of GdBaCuO bulks

A batch process for fabrication of GdBa₂Cu₃O_y pellets in air was developed. The samples were melt-processed using the cold-seeding method and as seeds Nd-123 thin films grown on MgO crystals. We used a self-made Gd-123 and Gd-211 powders mixed with 0.1 wt.% of Pt. Up to 1–1.5 kg of melt-grown Gd-123 bulks can be prepared in one process. XRD results confirmed that all the bulks are c-axis oriented. The superconducting and magnetic performance of the pellets is checked on several small test samples cut out at various standard positions within the bulk. The values are quite uniform and performance is similar to the oxygen-controlled melt-grown Gd-123 samples. The average trapped field at 77 K in the 24 mm diameter samples batch lies between 0.8 and 0.9 T. The maximum trapped field of 1 T at the sample surface was the highest value reported so far for Gd-123 single grains processed in air. The present results prove that a high-performance good-quality LREBa₂Cu₃O_y material can scale up from laboratory conditions to industrial production.     

In Situ Transmission Electron Microscopy Observation of Melted Germanium Encapsulated in Multilayer Graphene

Germanene is a two-dimensional germanium (Ge) analogous of graphene, and its unique topological properties are expected to make it a material for next-generation electronics. However, no germanene electronic devices have yet been reported. One of the reasons for this is that germanene is easily oxidized in air due to its lack of chemical stability. Therefore, growing germanene at solid interfaces where it is not oxidized is one of the key steps for realizing electronic devices based on germanene. In this study, the behavior of Ge at the solid interface at high temperatures is observed by transmission electron microscopy (TEM). To achieve such in situ heating TEM observation, this work fabricates a graphene/Ge/graphene encapsulated structure. In situ heating TEM experiments reveal that Ge like droplets move and coalesce with other Ge droplets, indicating that Ge remains as a liquid phase between graphene layers at temperatures higher than the Ge melting point. It is also observed that Ge droplets incorporate the surrounding amorphous Ge as Ge nuclei, thereby increasing its size (domain growth). These results indicate that Ge crystals can be grown at the interface of van der Waals materials, which will be important for future germanene growth at solid interfaces.     

Creation of a thermostable firefly luciferase with pH-insensitive luminescent color

The thermal instability and pH-sensitive spectral property of firefly luciferase have hampered its use as a sensitive multicolor luminescent label or bioluminescent resonance energy transfer donor. With the intention of improving the thermostability of a previously found firefly Hotaria parvula luciferase mutant with minor pH-sensitive spectral change (V368A), further mutation (E356R) was introduced by taking a reportedly stabilized mutant of Photinus pyralis luciferase into account. The double mutant E356R/V368A showed significantly improved thermostability because > 90% activity remained after incubation for 1 h at 45 degrees C, with its specific activity being maintained. Unlike the wild type or V368A, E356R/V368A showed no change in the emission maximum of 568 nm even at pH 6.3, also implying a mutual relationship between thermostability and the proportion of yellow-green luminescent peak under acidic condition.     

Conditions for boundedness into Hardy spaces

We obtain the boundedness from a product of Lebesgue or Hardy spaces into Hardy spaces under suitable cancellation conditions for a large class of multilinear operators that includes the Coifman–Meyer class, sums of products of linear Calderón–Zygmund operators and combinations of these two types.     

A new synthetic method of α-amino acids from α-methoxyurethanes

Reaction of α-methoxyurethanes with phenylisocyanide gave the corresponding amides of α-amino acid in reasonable yields.     

Enhancement of saccharin removal from aqueous solution by activated carbon adsorption with ultrasonic treatment

This study investigates the use of ultrasonication as a pretreatment process and its effect on the adsorption characteristics of saccharin onto activated carbon (AC). Ultrasonic decomposition of saccharin was performed at a frequency of 500 kHz under argon and O2/N2 (20/80 vol%) atmospheres. Adsorption was carried out using a commercial activated carbon. The behavior of total organic carbon (TOC) during ultrasonication was investigated. Saccharin removal after 180 min of ultrasonication under Ar and O2/N2 atmospheres are 38% and 26%, respectively, while the amount of saccharin removed by activated carbon adsorption without US pretreatment is 40% after 16 h. After 16 h of AC adsorption with 180 min of ultrasonic pretreatment under Ar and O2/N2 atmospheres, both removal ratios increased to 75%. These results indicated that the pretreatment of sonication under O2/N2 leads to the increase in the amount of saccharin adsorbed on AC. On the other hand, the TOC removal by decomposition by ultrasound is not more than 5% in both Ar and O2/N2 atmospheres after 180 min ultrasonication. However, the TOC removal increased to 54% and 69% after 16 h of adsorption of saccharin pretreated by ultrasonication for 180 min under Ar and O2/N2 atmospheres, respectively. About 13% and 16% TOC removal in Ar and in O2/N2, respectively, were achieved due to adsorption of the by-products. It is considered that the improvement in TOC removal is also brought about by the formation of the by-products that were adsorbed onto AC.     

Stereospecific and biomimetic synthesis of CS and C2 symmetric 2,5-disubstituted tetrahydrofuran rings as central building blocks of biogenetically intriguing oxasqualenoids

The enantioselective synthesis of optically active (+)-tetraol 12, corresponding to the C9–C16 subunit of biogenetically and biologically intriguing oxasqualenoids 2–4, has been accomplished by the biomimetic and stereospecific cyclization of diepoxide 22. The experimental details for the preparation of the known meso tetraol 11, corresponding to the C9–C16 subunit of teurilene 1, are also described.     

Iterated maximal functions in variable exponent Lebesgue spaces

In this paper we study the iterated Hardy?CLittlewood maximal operator in variable exponent Lebesgue spaces with exponent allowed to reach the value 1. We use modulars where the L ^p(·)-modular is perturbed by a logarithmic-type function, and the results hold also in the more general context of such Musielak?COrlicz spaces.     

An example of finite dimensional Kac algebras of Kac-Paljutkin type

An example of finite dimensional Kac algebras of Kac-Paljutkin type is given.