New approach to environmentally benign epoxidation: the solid-phase-system using urea–H2O2 and recyclable dodecatungstate on apatite

On the basis of new concept using a solid disperse phase we have developed an efficient catalytic solid-phase-system for epoxidations of alkenes using urea–hydrogen peroxide (urea–H₂O₂) complex and cetylpyridinium dodecatungstate ((CetylPy)₁₀[H₂W₁₂O₄₂]) catalyst on fluorapatite (FAp). The recovered solid catalyst phase was reused to keep the catalytic activity after several times. In the conceptual idea it is a key point that in situ solid-phase-activation of the catalyst with urea–H₂O₂ proceeds to form microcrystals of the active species dispersed on the solid phase. The dispersion of the catalyst on FAp in the case of tungstic acid (H₂WO₄) was suggested by EPMA analysis. We proposed the peroxo type of species keeping the parent polyoxometalate framework as novel active species from FT-IR spectroscopic studies. FAp phase plays important roles of dispersing the active species on its surface to have high catalytic activity and of stabilizing the active species to lead to high reusability.     

Radiation tolerance for the SMASH-series front-end chips for a silicon micro-strip detector

The radiation tolerance for prototype front-end chips designed for a silicon micro-strip detector was examined with a ⁶⁰Co irradiation source to establish an allowable range of the radiation dose. The irradiated front-end chips were SMA²SH-64A, a 64-channel preamplifier array; SMA²SH-1, a single-channel preamplifier circuit with a comparator; and Control-C, a digital-control chip for the preamplifiers.     

Crosslinked acrylic pressure sensitive adhesives. 3. Effect of adherend on film formation

The reaction of isocyanate in pressure sensitive adhesive (PSA) films adhered on to various adherends having different surface tensions was monitored by depth profiling using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy.In the latter stages of crosslinking reaction, unreacted isocyanate and its derivatives exist more in the bulk of the PSA than in the interfaces between PSA and adherends which are Teflon sheet and PE film having relatively lower surface tensions. In the case of using stainless steel having relatively higher surface tension as adherend, opposite segregation was observed compared to Teflon and PE.From X-ray photoelectron spectroscopy (XPS), it was revealed that N atoms exist more in surface than in bulk when stainless steel is used as adherend. We conclude that polyisocyanates migrate in the PSA film in order to minimize the magnitude of interfacial free energy between the PSA and the adherend, which leads to the change of surface tension of PSA film.     

Microstructure and mechanical properties of hot extruded Mg–Al–Mn–Ca alloy produced by rapid solidification powder metallurgy

The microstructure and mechanical properties of hot extruded Mg–Al–Mn–Ca alloy was investigated. Both rapid solidified powders and cast billets were extruded at 573, 623 and 673 K to optimize the processing conditions for obtaining better mechanical response. Powder was consolidated to prepare the extrusion billets using both cold compaction and Spark Plasma Sintering at 473 K. The tensile properties of the extruded alloy were then evaluated and correlated to the observed microstructure. The results show that the use of rapid solidified powder could lead to effective grain refinement, which in turn resulted in the improved mechanical response, especially compared to the extruded conventional cast material.     

Determination of γ-glutamyl-valyl-glycine in raw scallop and processed scallop products using high pressure liquid chromatography–tandem mass spectrometry

The determination of the kokumi peptide, γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly) in raw scallop and processed scallop products was carried out using high pressure liquid chromatography–tandem mass spectrometry (LC/MS/MS). The detection of γ-Glu-Val-Gly was achieved using a multiple reaction monitoring (MRM) method. The optimised condition enabled the precise determination of γ-Glu-Val-Gly. Raw scallop contained 0.08 μg/g γ-Glu-Val-Gly, and the γ-Glu-Val-Gly levels in processed scallop products, such as dried-scallop and scallop extract, were measured to be 0.64 and 0.77 μg/g, respectively. This is the first report to confirm the existence of γ-Glu-Val-Gly in foodstuff.     

Slippage of 4He Films and Precursor Phenomenon of Superfluidity

We have carried out quartz crystal microbalance (QCM) experiments for ⁴He films on an exfoliated single-crystalline graphite using a 32 kHz tuning fork, and have measured the temperature dependence of the resonance frequency and the Q value for various areal densities and oscillation amplitudes. Comparing with the previous experiments for Grafoil, the decoupling of the films due to the slippage or the superfluidity was larger than that of Grafoil, and the competition between the slippage and the superfluidity was observed in three-atom thick films. Furthermore, it was found that the slippage is suppressed gradually at higher temperature than the superfluid onset T _c , and that the relaxation time decreases at low temperatures while it obeys the Arrhenius law at high temperatures. These results suggest a precursor to the superfluidity of ⁴He films.     

Changes in the nitrogen balance in agricultural land in Japan and 12 other Asian Countries based on a nitrogen-flow model

Gross and per unit agricultural land area nitrogen balance (NB _G and NB _A, respectively) in agricultural areas were estimated with a nitrogen-flow model for 13 Asian countries, for regions within a country, and for individual grid cells, from 1970 to 2005. Country- and regional-level estimates showed that NB _A is higher in Japan and South Korea than in other Asian countries, but has recently been stable or decreasing. The contribution of inorganic fertilizer to the nitrogen input is decreasing, whereas that of livestock manure is increasing in these countries. In many other countries, the primary nitrogen source is inorganic fertilizer and its input rate and NB _A have increased sharply since the 1980s. NB _A of some Chinese provinces and Indian states were as high as those of Japan and South Korea. The results suggest that regional-scale estimation is necessary because of the large spatial variability in nitrogen flows within a country. Based on the NB _G estimated for each 0.5°?×?0.5° grid cell, nitrogen outflow from agriculture into major river basins was evaluated. About 20?% of the nitrogen balance flowed into China??s Changjiang River basin, versus 10?% into the Ganges River basin. Uncertainties in the basic data and estimation results, and the use of an alternative measure of a country??s environmental performance were discussed.     

Effect of CNTs on Activation Volume and Mobile Dislocation Exhaustion Rate of CNTs/Al under Compression Loading

In this study, stress relaxation compression tests were performed to investigate the strain rate sensitivity, activation volume and mobile dislocations in carbon nanotubes/aluminum (CNTs/Al) composites. The results reveal that, with the addition of CNTs, the strain rate sensitivity of CNTs/Al increased. Meanwhile, a smaller V^* of CNTs/Al compared with pure Al was attributed mainly to the CNT-Al interfaces and partly to the increased forest dislocations cutting activities in grain interior, which was related to the tendency of short ranges order formation during plastic deformation. The incorporation of CNTs also improved the dislocation storage capability and reduced the dislocation velocity, leading to a lower mobile dislocation exhaustion rate.     

Determination of residual avoparcin in chicken muscle by HPLC with ultraviolet and amperometric detection

An analytical method was developed for determination of residual avoparcin in chicken muscle by measuring alpha- and beta-avoparcin, major components of the pharmaceutical preparation avoparcin, using HPLC with UV and amperometric detectors. The analytical HPLC was run on a Cosmosil 5C18-AR column (4.6 mm x 25 cm) with a gradient formed from A: 2.5% acetic acid, 0.01 mol/L sodium heptane sulfonic acid-acetonitrile (88.5:11.5) (pH 4.0) and B: 2.5% acetic acid-acetonitrile (10:90), using UV and amperometric detection (AMD) with glassy-carbon electrode (+900 mV). Avoparcin was extracted from chicken muscle by homogenization with methanol-0.2 mol/L sulfuric acid (6:4) followed by centrifugation after pH adjustment to 4 with 1 mol/L sodium hydroxide. The supernatant was evaporated to dryness, and the residue was dissolved in water. The aqueous layer was adjusted to pH 4 by adding 1 mol/L sodium hydroxide. Then it was purified on a Sep-Pak tC18 plus ENV cartridge. The cartridge was washed with water, and retained substances were eluted with 50% methanol. The eluate was evaporated to dryness under reduced pressure. The residue was dissolved in water and determined by HPLC. Recoveries of avoparcin spiked in chicken muscle were 73.1-88.1% at levels of 2-10 micrograms/g. The detection limits were 0.5 microgram/g (UV) and 0.2 microgram/g (AMD).