Preparation and Elastic Properties of rf-Sputtered Amorphous Films in the System SiO2-Y2O3

Amorphous films in the SiO₂-Y₂O₃ system were prepared by the rf-sputtering method. Transparent amorphous films were obtained in the region between 0 and 66 mol% Y₂O₃ content, only in an oxygen atmosphere. The densities and elastic constants of the films were determined. As the amount of Y₂O₃ addition increased, density and elastic constants increased up to about 45 mol% Y₂O₃, beyond which it held constant. From the relationship between the bulk modulus and the mean atomic volume, a structural change in the present films seems to occur at about 45 mol% Y₂O₃ content.     

Properties and Network Constitution of rf-Sputtered Amorphous Films in the System Silicon Dioxide–Aluminum Orthophosphate

Amorphous films in the system SiO₂–AlPO₄ were prepared by means of the rf-sputtering method, and their physical properties, such as density, refractive index, and temperature coefficient of Young's modulus, and infrared spectra were measured. Also, the K α X-ray emission spectra of silicon and aluminum were measured in order to investigate the coordination state of these cations in the amorphous films. The density and the refractive index were close to those of amorphous SiO₂ and AlPO₄ and the compositional dependence showed a small deviation from linearity. The temperature coefficients of Young's modulus were positive for all of the samples. The infrared absorption spectra of all of the samples were similar to those of SiO₂ glass and amorphous AlPO₄ film, and there was no evidence of the presence of P═O bonds. The coordination states of silicon and aluminum ions in the present amorphous films were the same as those in fused silica and AlPO₄ crystal, respectively. The results of the properties, infrared absorption spectra, and X-ray emission spectra suggest that SiO₄ tetrahedrons and AlO₄–PO₄ connecting tetrahedral dimers constitute the network of the present amorphous films. A small deviation of the physical properties from an additive rule was thought to result from the difference in the bond character between the newly formed Si–O–Al and Si–O–P bonds and the bonds in the end members, Si–O–Si and Al–O–P.     

Shrinkage Behavior of Knoop Indentations in Silica and Soda–Lime–Silica Glasses

The annealing characteristics of Knoop-indented silica and soda–lime–silica glasses were investigated. These glasses were indented using a Knoop indenter in water, and they were annealed at various temperatures below the glass transition temperature. The major diagonal length of the Knoop indentation was measured before and after annealing, and the change of the diagonal length was determined. The change of diagonal length in silica glass was much larger than that in soda–lime–silica glass. This was attributed to the occurrence of more densification around the Knoop indentation in the silica glass. The activation energy of the shrinkage of the Knoop indentation in the silica glass, estimated from the temperature dependence of the relaxation time, was 46 kJ/mol, which was much less than that of viscous flow in silica glass. This suggested that the shrinkage of the Knoop indentation was caused by the structural relaxation of densified glass around the Knoop indentation.     

Mössbauer Spectroscopy of Borate Glasses Containing Divalent Europium Ions

Borate glasses containing 0.99–30.0 mol% EuO have been prepared under a reducing atmosphere and ¹⁵¹Eu Mössbauer effect measurements have been carried out at room temperature in order to examine the chemical state of Eu²⁺ ions in these glasses. Mössbauer spectra indicate that most of the europium ions are present as the divalent oxidation state. In dilute Eu²⁺-containing borate glasses, spectra are split due to paramagnetic hyperfine interactions in the glasses with low and high sodium contents. In concentrated Eu²⁺-containing borate glasses, line broadening results from the contribution of quadrupole splitting due to asymmetrical oxygen coordination around Eu²⁺ and the contribution of inhomogeneous broadening due to site-to-site variation. The compositional dependence of isomer shift and quadrupole interaction parameter can be related to the structural changes in the borate glass. The variation of the isomer shift has a good correlation with the optical basicity of glass, and the trend can be explained in terms of the covalent admixture with 6 s character. The Eu-O bond in the borate glasses is more ionic than that in EuTiO₃ and EuZrO₃, where the oxygen coordination number for Eu²⁺ is 12. The average coordination number for Eu²⁺ is found to be 12 in all of the present glasses.     

Catechol - an Oviposition Stimulant for Cigarette Beetle in Roasted Coffee Beans

The cigarette beetle, Lasioderma serricorne, is a serious global pest that preys on stored food products. Larvae of the beetle cannot grow on roasted coffee beans or dried black or green tea leaves, although they oviposit on such products. We investigated oviposition by the beetles on MeOH extracts of the above products. The number of eggs laid increased with an increase in dose of each extract, indicating that chemical factors stimulate oviposition by the beetles. This was especially true for \ coffee bean extracts, which elicited high numbers of eggs even at a low dose (0.1 g bean equivalent/ml) compared to other extracts. Coffee beans were extracted in hexane, chloroform, 1-butanol, MeOH, and 20 % MeOH in water. The number of eggs laid was higher on filter papers treated with chloroform, 1-butanol, MeOH, and 20 % MeOH in water extracts than on control (solvent alone) papers. The chloroform extract was fractionated by silica-gel column chromatography. Nine compounds were identified by gas chromatography/mass spectrometry from an active fraction. Of these compounds, only a significant ovipositional response to catechol was observed.     

Dietary Marine-Derived Tocopherol has a Higher Biological Availability in Mice Relative to Alpha-Tocopherol

The biologic availability of two kinds of tocomonoenols, marine-derived tocopherol (MDT) and α-tocomonoenol, was investigated in ICR mice. Vitamin E-deficient ICR mice were fed MDT and α-tocomonoenol together with α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol, and storage in liver, spleen, lung, and brain was quantified using reverse-phase high-performance liquid chromatography. The vitamin E relative biologic availability (VE-RBA) in liver was 100 for α-tocopherol, 26 ± 3 for β-tocopherol, 4 ± 2 for γ-tocopherol, not detected for δ-tocopherol, 49 ± 6 for MDT, and 30 ± 7 for α-tocomonoenol. The VE-RBA in brain was 100 for α-tocopherol, 5 ± 2 for β-tocopherol, not detected for γ-tocopherol and δ-tocopherol, 8 ± 1 for MDT, and 4 ± 1 for α-tocomonoenol. Tocopherols and tocomonoenols did not accumulate in the spleen or lung. MDT and α-tocomonoenol had high VE-RBA values. The VE-RBA value for MDT was much higher than that for β-tocopherol.     

Preparation of Macroporous Titania Films by a Sol-Gel Dip-Coating Method from the System Containing Poly(ethylene glycol)

Macroporous titania (TiO₂) films have been prepared via a sol-gel dip-coating method from a titanium tetraisopropoxide solution that contains poly(ethylene glycol) (PEG). The macroporous morphology-i.e., the size, distribution, and shape of the macropores-is controlled by varying the content and molecular weight of PEG, the withdrawal speed, and the temperature of the dipping solution. The morphology of the TiO₂ film is determined by competitive contributions of the following factors: (i) decrease in fluidity, because of the evaporation of solvent; (ii) network formation by polycondensation reactions; and (iii) domain formation during phase separation into gel phases and solvent phases.     

Communication Gap Management for Fertile Community

In the paper, we first present an approach to extract social networks from message boards on the Internet. Then we propose communication gaps based on structural features of the social networks as an indicator of understanding the state of communication. After we classify 3,000 social networks into three types of communication, i.e., interactive communication, distributed communication, and soapbox communication, we suggest communication gap management to identify the types of communication, the roles of individuals, and important ties, all of which can be used for drawing up a plan for realizing fertile community.     

Influence of aluminum nitride interlayers on crystal orientation and piezoelectric property of aluminum nitride thin films prepared on titanium electrodes

Highly c-axis-oriented aluminum nitride (AlN) thin films have been prepared on titanium (Ti) bottom electrodes by using AlN interlayers. The AlN interlayers were deposited between Ti electrodes and silicon (Si) substrates, such as AlN/Ti/AlN/Si. The crystallinity and crystal orientation of the AlN films and Ti electrodes strongly depended on the thickness of the AlN interlayers. Although the sputtering conditions were the same, the X-ray diffraction intensity of AlN (0002) and Ti (0002) planes drastically increased, and the full-width at half-maximum (FWHM) of the X-ray rocking curves decreased from 5.1° to 2.6° and from 3.3° to 2.0°, respectively. Furthermore, the piezoelectric constant d₃₃ of the AlN films was significantly improved from − 0.2 to − 4.5 pC/N.