Local stability of composite systems--Frequency-domain condition and estimate of the domain of attraction

This paper is concerned with such composite systems whose subsystems contain one nonlinearity each and whose interconnections are functions of the scalar outputs of subsystems. A frequency-domain condition which assures local asymptotic stability is given under the assumptions that each nonlinearity satisfies a sector condition, that interconnections are linearly bounded, and that linear parts of subsystems may have unstable poles. In deriving the above result, such Lyapunov functions of subsystems are constructed so that their weighted sum is a Lyapunov function of the overall system. A method to estimate the domain Of attraction based on the above Lyapunov functions is also studied. When the bounds on nonlinearities hold true in the entire space and when the linear parts do not have unstable poles, the present condition turns out to be the same with the L2-stability condition which was obtained before by Araki.     

On preventing sugar-coated tablets from browning

The phenomenon of browning occurs gradually in the white sugar-coating layer (comprised of sucrose, talc, and powdered acacia) when the coating is applied on a large scale. We found that this phenomenon is negligible on sugar-coated tablets when they are prepared on a small scale. The smoothing layer prepared on a small scale is nearly as opaque as the subcoating layer. Conversely, the smoothing layer produced on a larger scale is semitransparent. In large-scale operations, the conditions required to make the smoothing layer opaque were established, and it was demonstrated that this method can restrict the browning phenomenon. It is considered that the nitrogen-containing contaminants in powdered acacia may react with heat-inverted sucrose (the Maillard reaction) to make brown substances in the smoothing layer and that the opaque appearance of the layer conceals the color accumulation of the brown substances in the smoothing layer and therefore restricts the browning phenomenon.     

A soft-solution process for recovering rare metals from metal/alloy-wastes by grinding and washing with water

We have developed a novel process for recovering metals from alloy-wastes by using a mechanochemical (MC) reaction. The process consists of co-grinding both alloy and polyvinyl chloride (PVC) samples, followed by washing with water and filtration. The co-grinding of the wastes causes a solid-state MC reaction to form metal chlorides and hydrocarbon in the product. The former products are soluble in water, so they can be recovered from the wastes by washing with water, followed by filtration. The PVC waste plays a significant role as a chlorine source in the MC reaction. After filtration, the solid residue can be used as a fuel, due to the absence of chlorine in the product, and the filtrate is subjected to hydrometallurgical process to extract metals from the solution.     

Reversible Control of Radius and Morphology of Fluorene‐Azobenzene Copolymer Nanowires by Light Exposure

The preparation of photoresponsive polymer nanowires comprising photochromic azobenzene (Azo) and π‐conjugated fluorene (FO) units is reported. Well‐defined and uniform nanowires of the copolymer (PFOAzo) were successfully fabricated by the single particle nanofabrication technique after optimizing the FO:Azo ratio and the development conditions. Azo units in the PFOAzo nanowires underwent reversible trans–cis–trans isomerization upon exposure to ultraviolet or visible light, leading to changes in the radius (between ca. 6 and 8 nm) and morphology (straight or wavy) of the nanowires. The oligo(alkylfluorene) units in the backbone are found to profit the crosslinking efficiency upon high‐energy ion beam irradiation, and more importantly, provide sufficient flexibility to allow reversible photoswitching. This demonstration of the photoluminescence, semiconducting, and mechanical properties of the PFOAzo nanowires is an important advance in the evolution of electro‐mechanical nanomaterials.     

Characterization of Fish Myofibrillar Protein by Conjugation with Alginate Oligosaccharide Prepared Using Genetic Recombinant Alginate Lyase

ABSTRACT: The production of alginate lyase using genetically modified Escherichia coli was superior to the purification of alginate lyase from a culture medium of Pseudoalteromonas elyakovii regarding production efficiency. When alginate oligosaccharide (AO) prepared using genetic recombinant alginate lyase was introduced to fish myofibrillar proteins, the protein obtained high water solubility and improved thermal stability, similarly to AO prepared using wild-type lyase. Therefore, the use of genetic recombinant technology for the production of alginate lyase would be useful for the functional improvement of fish myofibrillar proteins by conjugation with AO.