Fabrication of Photonic Crystal with a Diamond Structure Having an Air Cavity Defect and its Microwave Properties

Three-dimensional photonic crystals with a diamond lattice structure consisting of 5 × 5 × 5 unit cells with the unit cell dimension of 15 mm were fabricated using TiO₂-based ceramic particles dispersed epoxy by stereolithography. The diamond lattice showed a perfect band gap between 14.3 and 15.8 GHz. An air cavity defect with a rectangular shape (15 mm × 45 mm × 15 mm) was introduced at the center of the crystal by extracting 3 unit cells in order to investigate the shape effect of the defect on the formation of localized defect modes of electromagnetic wave. When microwaves were radiated normal to the wide sides (45 mm × 15 mm) of the rectangular shape defect, a sharp localized mode appeared at the middle of the band gap. However, no localized mode was observed for incident waves normal to the smaller side (15 mm × 15 mm) because of the symmetry mismatching between internal eigenmodes in the defect cavity and incident plane waves. The mode analysis using a simple cavity model showed the penetration of the electric field of resonant modes about 2.4 mm into the host lattice.     

Successive entrapping of red and yellow quinoid chalcones from aqueous extracts of dyer's saffron florets: a newly established and practically approved technique

Summary A setup for successive entrapping of red and yellow quinoid chalcone pigments was assembled. The device consists of four parts: a unit for the extraction of the pigments, a unit for their transfer to the column, a unit for entrapping the columns and a unit for releasing the trapped substances. The device enables us to extract the naturally occurring oxygen-labile, pH-sensitive and UV-fragile pigments on an economically approved scale.

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Schrittweises Freimachen von roten und gelben chinolden Chalkonen aus wäßrigen Extrakten von Safranblütenfarben; eine neue entwickelte und geprüfte Technik

Zusammenfassung Es wurde ein Plan fur das schrittweise Freimachen von roten und gelben chinoiden Pigmenten entwickelt. Die Arbeitsweise besteht aus vier Schritten. zuerst in der Extraktion der Pigmente, dann deren Überführung in die Säule, daraufhin das Freimachen aus der Säule und schließlich das Freisetzen der abgeschiedenen Stoffe. Dieses Vorgehen ermöglicht, die pH-, 02- und UV-empfindlichen Stoffe ökonomisch und gezielt zu gewinnen.

     

Coal gasification using a molten iron bath

A coal gasification process using a molten iron bath as reactor has been developed by Sumitomo Metals. Pulverized coal is blown onto this molten iron together with oxygen and steam as gasification agents. Tests using a pilot plant having a capacity of 60 t (coal) day^?1, has shown that a sulphur-free carbon monoxide and hydrogen-rich gas can be generated at high coal conversion efficiency.     

Characteristics of a high-concentration-ammonium sulfate-requiring ammonia-oxidizing bacterium isolated from deodorization plants of chicken farms

A high-concentration-ammonium sulfate-requiring, ammonia-oxidizing bacterium, strain K1, was newly isolated from packed tower biological deodorization plants of chicken farms. The cells of strain K1 are rods (0.1-1.0 x 1.0-2.0 microm), gram negative, obligately aerobic, and nonmotile. Colonies (1-2 mm in diameter) on a plate culture are reddish, circular, and smooth. Intracytoplasmic membranes characteristic of nitrifying bacteria are present. The G+C content of the total DNA is 48.5 mol%. The similarity of 16S rRNA (%) to N. europaea ATCC 25978T (type strain) is 93.77%. This bacterium has a higher optimal growth temperature (35 degrees C) than is usually the case and tolerance up to 40 degrees C. The optimum concentration of ammonium sulfate in the medium is 303 mM, which should make it applicable for use in deodorization plants for enhancing the efficiency of deodorization. Phosphoglycerate kinase (PGK) and triosephosphate isomerase (TIM) were found to possess high specific activities (5700 and 4 x 10(5) U/mg, respectively) compared to the activities of these enzymes in strain ATCC 25978T (300 and 14 U/mg).     

5, 10-linked naphthodithiophenes as the building block for semiconducting polymers

We present new semiconducting polymers incorporating naphtho[1, 2-b:5, 6-b′] dithiophene (NDT3) and naphtho[2, 1-b:6, 5-b′] dithiophene (NDT4), which are linked at the naphthalene positions, in the polymer backbone. It is interesting that the trend in the ordering structure and thus charge transport properties are quite different from what were observed in the isomeric polymers where the NDT3 and NDT4 cores are linked at the thiophene α-positions. In the thiophene-linked NDT system, the NDT3-based polymer (PNDT3BT) gave the better ordering in thin films and thus the high charge carrier mobility compared to the NDT4-based polymer (PNDT4BT). In the meantime, in the naphthalene-linked NDT system, the NDT4-based polymer (PNDT4iBT) provided the superior properties. Considering that PNDT4iBT has relatively low highest occupied molecular orbital (HOMO) energy level (−5.2 eV) and moderately high mobilities in the order of 10⁻² cm² V⁻¹ s⁻¹, the NDT4 core, when linked at the naphthalene positions, can be a good building unit for the development of high-performance semiconducting polymers for both organic field-effect transistors and photovoltaic devices.     

Effects of gas adsorption on the electrical conductivity of single-wall carbon nanohorns

We present significant electrical conductivity responses of the pelletized as-prepared and oxidized (ox-) single-wall carbon nanohorns (SWNHs) on adsorption of CO(2) and O(2). The morphological and pore structures of both pelletized SWNHs were examined by transmission electron microscopy (TEM) and nitrogen adsorption isotherm, leading to explicit evidences of the formation of nanoscale windows on the wall by oxidation. The SWNH and ox-SWNH induced a semiconducting behavior, strongly responded to CO(2) and O(2) adsorptions, and each exhibited n-type- and p-type-like conductivities. The electrical conductivity increase and decrease for CO(2) and O(2) adsorption, respectively, were observed for SWNH, whereas ox-SWNH showed a marked electrical conductivity drop on CO(2) adsorption and almost no change on O(2) adsorption. The dramatically different electrical conductivity response of ox-SWNH is presumed to be ascribed to the annihilation of pentagons in the single graphene wall by oxidation.     

A Coalgebraic Representation of Reduction by Cone of Influence

The Cone of Influence Reduction is a fundamental abstraction technique for reducing the size of models used in symbolic model checking. We develop coalgebraic representations of systems as composites of state transition maps and connectors. These representations include synchronous systems, asynchronous systems, asynchronous systems with synchronization by channels, and those with shared variables, probabilistic synchronous systems and so on. We schematically show the cone of influence reduction using these coalgebraic representations, which give a unified framework for providing the technique for various kinds of systems.     

Periodic nanovoid structures via femtosecond laser irradiation

We have observed periodically aligned nanovoid structures inside a conventional borosilicate glass induced by a single femtosecond (fs) laser beam for the first time, to our knowledge. The spherical voids of nanosized diameter were aligned spontaneously with a period along the propagation direction of the laser beam. The period, the number of voids, and the whole length of the aligned void structure were controlled by changing the laser power, the pulse number, and the position of the focal point.     

Enhanced spin accumulation and novel magnetotransport in nanoparticles

Spin injection and accumulation are key phenomena supporting a variety of concepts for spin-electronic devices. These phenomena are expected to be enhanced in nanoparticles over bulk structures due to their discrete energy levels and large charging energies. In this article, precise magnetotransport measurements in the single-electron tunnelling regime are performed by preparing appropriate microfabricated devices containing cobalt nanoparticles. Here we provide experimental evidence for characteristic features of spin accumulation in magnetic nanoparticles, such as oscillations of the magnetoresistance with a periodical sign change as a function of bias voltage. Theoretical analysis of the magnetoresistance behaviour clearly shows that the spin-relaxation time in nanoparticles is highly enhanced in comparison with that in the bulk.