Composite materials reinforced with polyoxymethylene whiskers

Various composite samples reinforced with polyoxymethylene (POM) whisker crystals were prepared and their Young's moduli were measured and analysed, on a theoretical equation, to estimate the modulus of the filler itself. Good reinforcement was obtained with matrix resins such as an epoxide and an unsaturated polyester, the results giving the modulus of the whisker to be approximately 1×10¹¹ N m^–2, i.e., almost equivalent to the ideal crystal modulus of POM. Some acoustic properties were investigated for sheet composite materials prepared with a polyolefin polymer for matrix. The sonic velocity attained was more than twice that of the matrix polymer, at larger filler contents, while the internal dynamic loss was maintained at a reasonably high level. Loudspeakers carrying diaphragms of the composite sheets showed improved frequency characteristics in the high-frequency region. Some morphological observations were made for the crystals embedded in resins.     

Evidence that activation of Src family kinase is not required for fertilization-associated [Ca2+]i oscillations in mouse eggs

Recent evidence in marine invertebrate, frog, and zebrafish eggs suggests the involvement of a Src family kinase (SFK) in fertilization-induced Ca2+ release. In the present study, we have investigated whether activation of an SFK is required for initiation of intracellular Ca2+ ([Ca2+]i) oscillations in mouse fertilization. We detected a Hck-like protein and tyrosine-phosphorylated proteins in soluble and insoluble sperm fractions, respectively. However, the presence of these proteins did not correspond to the active fractions of porcine sperm extracts (pSE). Moreover, [Ca2+]i oscillations induced by pSE in mouse eggs were unaltered by pre-incubation of pSE with specific SFK inhibitors such as 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazol[3,4-d]-pyrimidine (PP2) or lavendustin A, despite the fact that the inhibitors were shown to be active both in vivo and in vitro. Another SFK inhibitor, peptide A, blocked oscillations when incubated with pSE prior to injection into eggs, but this inhibition required more than ten times the concentration reportedly required to inhibit SFK activity. In addition, pre-injection or pre-incubation of eggs with these inhibitors did not affect the ability of pSE to trigger [Ca2+]i oscillations in mouse eggs. Microinjection of a recombinant c-Src protein or mRNAs encoding constitutively active Src proteins did not induce [Ca2+]i release. Finally, when sperm and eggs, both of which were pre-treated with PP2, were fertilized, [Ca2+]i oscillations occurred normally. We can therefore conclude that activation of an SFK is neither necessary nor sufficient for triggering fertilization-induced [Ca2+]i oscillations.     

Absorption phenomena in the treatment of cotton with formaldehyde and cyclic oxymethylenes

Monomeric formaldehyde and the cyclic oxymethylenes tetraoxane and pentaoxane were retained by cotton to similar extents at the high temperatures used in textile finishing, but the mechanisms of absorption appeared to differ. Trioxane, however, was not retained by cotton. The absorption of cyclic oxymethylenes did not seem to involve bonding to cellulose by primary valence bonds. The presence of other substances had a greater effect on the absorption of monomeric formaldehyde than of cyclic oxymethylenes, but changes in extent of absorption were not large enough to influence textile properties of treated fabric.     

Chemicofunctional membrane for integrated chemical processes on a microchip

Here we report a design and synthesis of a chemically functional polymer membrane by an interfacial polycondensation reaction and multilayer flow inside a microchannel. Single and parallel dual-membrane structures are successfully prepared by using organic/aqueous two-layer flow and organic/aqueous/organic three-layer flow inside the microchannel followed by an interfacial polycondensation reaction. By using the inner-channel membrane, permeation of ammonia species through the inner-channel membrane is successfully achieved. Furthermore, horseradish peroxidase is immobilized on one side of the membrane surface to integrate the chemical transform function onto the inner-channel membrane. Here substrate permeation through the membrane and subsequent chemical transformation at the membrane surface are realized. The polymer membrane prepared inside the microchannel has an important role in ensuring stable contact of different phases such as gas/liquid or liquid/ liquid and the permeation of chemical species through the membrane. Furthermore, membrane surface modification chemistry allows chemical transformation of permeated chemical species. These methods are expected to lead to development of complicated and sophisticated chemical systems involving membrane permeation and chemical reactions.     

On PH quintic spirals joining two circles with one circle inside the other

The paper derives a spiral condition, for a single Pythagorean hodograph quintic transition curve of G² contact, between two circles with one circle inside the other. A spiral is free of local curvature extrema, making spiral designs an interesting mathematical problem with importance for both physical and aesthetic applications. In the construction of highways or railway routes in particular, it is often desirable to have a transition curve from circle to circle. Here, we treat an open problem on planar quintic spiral segments, called transition curve elements, examine techniques for curve design using the new results, and derive lower and upper bounds for the distance between the two circles. The proposed method is applicable for non-tangent and non-concentric circles.     

Growth monitoring and classification of rice fields using multitemporal RADARSAT-2 full-polarimetric data

Spaceborne synthetic aperture radar (SAR) can be used for agricultural monitoring. In this study, three single-polarimetric and four full-polarimetric observation data sets were analysed. A rice paddy field in northern Japan was used as the study site; the data for this site were obtained using RADARSAT-2, which carries a full-polarimetric C-band SAR. Soybean and grass fields were also present within the paddy fields. The temporal change in the backscattering coefficient of the rice paddy fields for the single-polarization data agreed with the temporal change obtained for a rice growth model based on radiative transfer theory. A three-component decomposition approach was applied to the full-polarimetric data. With each rice growth stage, the volume scattering component ratio increased, whereas the surface scattering component ratio generally decreased. The soybean and grass fields showed a smaller double-bounce scattering component than the rice fields for all the acquired data. The results of this study show that multitemporal observation by full-polarimetric SAR has great potential to be utilized for estimating rice-planted areas and monitoring rice growth.     

Analysis of nonlinear transient responses of piezoelectric resonators

The electric transient response method is an effective technique to evaluate material constants of piezoelectric ceramics under high-power driving. In this study, we tried to incorporate nonlinear piezoelectric behaviors in the analysis of transient responses. As a base for handling the nonlinear piezoelectric responses, we proposed an assumption that the electric displacement is proportional to the strain without phase lag, which could be described by a real and constant piezoelectric e-coefficient. Piezoelectric constitutive equations including nonlinear responses were proposed to calculate transient responses of a piezoelectric resonator. The envelopes and waveforms of current and vibration velocity in transient responses observed in some piezoelectric ceramics could be fitted with the calculation including nonlinear responses. The procedure for calculation of mechanical quality factor Q(m) for piezoelectric resonators with nonlinear behaviors was also proposed.     

Automatic extraction of citation information in Japanese patent applications

The need for academic researchers to retrieve patents and research papers is increasing, because applying for patents is now considered an important research activity. However, retrieving patents using keywords is a laborious task for researchers, because the terms used in patents for the purpose of enlarging the scope of the claims are generally more abstract than those used in research papers. Therefore, we have constructed a framework that facilitates patent retrieval for researchers, and have integrated research papers and patents by analysing the citation relationships between them. We obtained cited research papers in patents using two steps: (1) detection of sentences containing bibliographic information, and (2) extraction of bibliographic information from those sentences. To investigate the effectiveness of our method, we conducted two experiments. In the experiment involving Step 1, we prepared 42,073 sentences, among which a human subject manually identified 1,476 sentences containing citations of papers. For Step 2, we prepared 3,000 sentences, in which the titles, authors, and other bibliographic information were manually identified. We obtained a precision of 91.6%, and a recall of 86.9% in Step 1, and a precision of 86.2% and a recall of 85.1% in Step 2. Finally, we constructed an information retrieval system that provided two methods of retrieving research papers and patents. One method was retrieval by query, and another was from the citation relationships between research papers and patents.     

Successive changes in community structure of an ethylbenzene-degrading sulfate-reducing consortium

The microbial community structure and successive changes in a mesophilic ethylbenzene-degrading sulfate-reducing consortium were for the first time clarified by the denaturing gradient gel electrophoresis (DGGE) analysis of the PCR amplified 16S rRNA gene fragments. At least ten bands on the DGGE gel were detected in the stationary phase. Phylogenetic analysis of the DGGE bands revealed that the consortium consisted of different eubacterial phyla including the delta subgroup of Proteobacteria, the order Sphingobacteriales, the order Spirochaetales, and the unknown bacterium. The most abundant band C was closely related to strain mXyS1, an m-xylene-degrading sulfate-reducing bacterium (SRB), and occurred as a sole band on DGGE gels in the logarithmic growth phase that 40% ethylbenzene was consumed accompanied by sulfide production. During further prolonged incubation, the dominancy of band C did not change. These results suggest that SRB corresponds to the most abundant band C and contributes mainly to the degradation of ethylbenzene coupled with sulfate reduction.     

Fractal dimension of the grain boundary fracture in creep-fracture of cobalt-based heat resistant alloys

The effects of grain boundary configuration and creep conditions on the fractal dimension of the grain boundary fracture (D _f) were investigated using commercial cobalt-based heat resistant alloys, namely, HS-21 and L-605 alloys. Creep-rupture experiments were carried out under the initial creep stresses of 19.6–176 MPa in the temperature range from 1089–1422 K in air. The value of D _f was larger in specimens with serrated grain boundaries than in those with straight grain boundaries in the HS-21 alloy under the same creep condition, and the difference in the value of D _f between these specimens was large in the scale range of the analysis which was less than about one grain boundary length. However, there was almost no difference in the value of D _f between the specimens with serrated grain boundaries and those with straight grain boundaries in the L-605 alloy, because there was no obvious difference in the microstructure between these specimens. The value of D _f increased with decreasing creep stress in the scale range of the fractal analysis larger than about one grain boundary length in both HS-21 and L-605 alloys, while the stress dependence of D _f was larger in the HS-21 alloy. The stress dependence of D _f was explained by the stress dependence on the number of grain boundary microcracks linked to the fracture surface. The value of D _f estimated in the scale range smaller than about one grain boundary length showed essentially no stress dependence in both L-605 and HS-21 alloys.