On-site fabrication of ceramics films from solution precursors by ink-jet and spray assisted processes

Solution processing based on Ink-jet and spray technologies is one of low cost on-site ceramic patterns/films fabrication methods at moderate temperatures from precursor solutions. In the present study, we have used ink-jet and spray technologies to fabricate ceramic films of titania directly on glass substrates at 300–400^∘C. The precursor solution was prepared by dissolving Titanium tetraisopropoxide in appropriate solvents (water/ethanol and acetylacetone). A cleaned glass substrate was kept on a hot plate and heated it up to a predetermined temperature. Droplets of the precursor solution produced through a spray gun were traveled towards heated substrate with a atmospheric pressure. When the droplets hit on the heated substrate, precursor started to decompose, nucleate and grow into the TiO₂ film. The anatase pattern was directly obtained by ink-jet method at moderate temperatures.     

Age-dependent dose conversion coefficients for external exposure to radioactive cesium in soil

To estimate effective doses for members of the public exposed to external radiation from radioactive cesium (¹³⁴Cs and ¹³⁷Cs) deposited on the ground by the Fukushima nuclear accident, we calculate the conversion coefficients for converting activity concentration to effective dose rate by using the Particle and Heavy Ion Transport Code System. The data were produced from different age groups within the public (newborns; 1-, 5-, 10-, and 15-year-old children; and adults) for the situations in which radioactive cesium is distributed uniformly in the soil over a planar area and at specific depths of 0.0, 0.5, 2.5, 5.0, 10.0, and 50.0 g/cm². On the basis of the results, we also derive the conversion coefficients for exponentially distributed volumetric sources. In addition, we obtain the conversion coefficients that give the effective dose accumulated over the first and second months, the first year, and over a lifetime (50 years) because of the contamination remaining on the ground. These calculations indicate that the conversion coefficients to obtain the effective dose rate are higher for the younger ages compared with adults, but do not exceed the ambient dose equivalent rate. Furthermore, we find that the difference between the calculated effective dose rates according to the International Commission on Radiological Protection 1990 and 2007 Recommendations is small (7% maximum) for a ground contamination of radioactive cesium.     

Plant designing of ion exchange chemical uranium enrichment and its non-proliferation aspects

The chemical uranium enrichment using ion exchanger had been developed mainly in Japan, but now only the academic studies have been continued at Tokyo Tech. For the purpose of revaluation as the alternative production process of the low enriched uranium for nuclear power plants, the plant design and the non-proliferation aspects of redox ion exchange chemical uranium enrichment (Redox Ion Exchange Method) were studied.The conceptual design of a commercial enrichment plant with a scale of 1400 tSWU/Y was newly performed based on data reported. It is composed of seven enrichment units with two enrichment columns with an inner diameter of 6.5 m and a height of 11 m and redox systems. It is evaluated as having the site area of 97,200 m² including the vacancy to double the production with subsidiary sections of pre-treatment and post-treatment of uranium or the like, a construction cost is 218 billion Japanese yen(JPY), and a cost per enrichment work is 18,000 JPY/kgSWU. As for the nuclear proliferation resistance of this process, it is suggested that the production of highly enriched uranium for weapon use is difficult from the view point of nuclear fission criticality and the lengthy equilibrium time mentioned as following. It is difficult to operate the enrichment plant for the production of highly enriched uranium of 50 wt% of ²³⁵U or higher, because the effective neutron multiplication factor (k_eff) in the enrichment columns becomes 1 or above depending on the enrichment conditions. And the required time for the production of highly enriched uranium of 90 wt% of ²³⁵U is estimated 10 thousands days or more, this means substantially impossible to get highly enriched uranium under the safeguard of IAEA by the Redox Ion Exchange Method.The Redox Ion Exchange Method is suggested to be a promising candidate for an alternative enrichment process to obtain low enriched uranium in the range 3-5 wt% ²³⁵U for nuclear power plant in the world. Furthermore, for the future prospective fuel cycle without UF₆, new front-end system coupled with uranium from seawater and chemical enrichment is proposed.     

Numerical simulation of MFM image of a magnetic nano-contact

A MFM image of a magnetic nano-contact is studied numerically. We show that the ring- or arc-shaped MFM images with diameter of the order of 100 nm appear while the size of a nano-contact is of the order of 1 nm. We also show that the origin of the ring or arc-shaped MFM image is the oscillation of the magnetization of a nano-contact induced by the interaction between the MFM-tip and the nano-contact.     

Fabrication of transparent ceria films by spray deposition without post firing

Most of the existing methods of crystalline ceria (CeO₂) films preparation consume much time and cost. Here we describe a straightforward and relatively cost-effective method of CeO₂ films preparation that involves direct spray deposition process on glass substrates at moderate temperatures (300–400 °C) using cerium acetate precursor in mixture of water and ethanol. X-ray diffraction analysis of obtained films revealed that they were polycrystalline, at least for a certain extent, with cubic fluorite structure and showed the existence of nanocrystallites. Scanning electron microscopic analysis showed that the films were crack-free and consists of nanocrystalline(<10 nm) ceria. Furthermore, the film showed high transparency in the visible and near-infrared region with calculated optical band gap (E _g) value of 3.06–3.08 eV. The film formation mechanism to obtain the transparent film has also been proposed.     

Effects of the alumina matrix on the carbonization process of polymer in the gel-casted green body

We propose a new convenient method for making nanocarbon/ceramic composites, which combines gel casting and firing in an inert atmosphere. The objective of this work was to clarify the effect of the alumina matrix on the carbonization process of the gel content in the gel-casted green body. The presence of the alumina matrix was found to assist the survival of functional groups such as amide groups during the thermal decomposition of the polymers. Consequently, the carbon content was in a form such that it could be easily graphitized at low temperatures. The prevention of the thermal decomposition of amide groups through the interaction between the surface of the ceramic grains and the polymers was found to be important in the graphitization of the carbon content and the attainment of high conductivity during the synthesis of nanocarbon/ceramic composites.     

Studies on the Dehydrogenative Polymerizations of Monolignol β-glycosides. Part 3: Horseradish Peroxidase–Catalyzed Polymerizations of Triandrin and Isosyringin

Abstract

Horseradish peroxidase–catalyzed dehydrogenative polymerizations of the p-hydroxyphenyl monolignol glucoside (triandrin (1P)) and the syringyl monolignol glucoside (isosyringin (1S)) resulted in the formation of water-soluble lignin-like polymers (DHPs). The polymerization of 1P gave highly polymerized DHPs in high yields as did previously reported polymerization of the guaiacyl monolignol glucoside (isoconiferin (1G)). It was shown that the hydrophilic D-glucose units of 1G and 1P contribute to a marked increase in the molecular weights of the resulting DHPs. On the other hand, the homogeneous phase polymerization of 1S, similar to the polymerization of sinapyl alcohol, gave DHPs with extremely low molecular masses in poor yields. Structural characterization indicated that the DHPs from 1P and 1S were lignin-like polymers containing glucosidic units on their sidechains. It was also confirmed that D-glucosyl units introduced onto the γ-position of monolignols do not significantly affect the electrochemical oxidizability and the kinetics of the HRP-catalyzed initial monomer consumption.     

α-Glucosidase Inhibition Activity by Cyclic Diarylheptanoids from Alnus sieboldiana

Abstract

A diarylheptanoid, named 3,17-dihydroxy-tricyclo[12.3.1.1^2,6]nonadeca- 1(18),2,4,6(19),14,16-hexaen-9,11-dione, was newly isolated from the branch wood of Alnus sieboldiana, together with two known diarylheptanoids. The chemical structure of this compound was assigned on the basis of the NMR and MS data, information obtained though 1D- and 2D-NMR analyses. These three diarylheptanoids were found to significantly inhibit the activity of α-glucosidase.     

Sex Pheromone Components of the Pear Fruit Moth, <Emphasis Type="Italic">Acrobasis pyrivorella</Emphasis> (Matsumura)

We analyzed the sex pheromone of the pear fruit moth, Acrobasis pyrivorella, by means of gas chromatography–electroantennographic detection (GC-EAD) and GC–mass spectrometry. Two EAD-active compounds were detected in the pheromone gland extract of females. They were identified as (Z)-9-pentadecenyl acetate (Z9-15:OAc) and pentadecyl acetate (15:OAc). The amounts per female gland (mean ± standard error) of these compounds were 12.9 ± 2.8 and 0.8 ± 0.1 ng, respectively. Synthetic Z9-15:OAc (300 μg) attracted conspecific males in field trapping experiments. When 15:OAc (21 μg; 7% of Z9-15:OAc quantity) was added, the number of males trapped increased significantly. Catch in traps baited with the mixture of these compounds was greater than that in traps baited with 1–3-day-old virgin females. We, therefore, conclude that Z9-15:OAc and 15:OAc are sex pheromone components of this species.