Bonelike Apatite Formation Induced on Zirconia Gel in a Simulated Body Fluid and Its Modified Solutions

Formation of bonelike apatite on zirconia gel in a simulated body fluid (SBF) with ion concentrations almost equal to those in human blood plasma, in modified SBF solutions to have increased pH values, and modified SBF solutions to have increased concentrations of calcium and phosphate ions has been investigated. The zirconia gel forms apatite on its surface in SBF, indicating that Zr-OH groups, abundant on the gel, act as effective apatite nucleation centers. Apatite formation is accelerated by increases in pH and in the concentration of calcium and phosphate ions, which is explained by an increase in the ionic activity product of the apatite in the SBF. These results suggest that zirconia ceramics may exhibit a bone-bonding ability by forming an apatite layer on their surfaces in the living body when they are modified to have many Zr-OH groups on their surfaces.     

Non-Chlorine Bleaching of Kraft Pulp II. Ozonation of Methyl 4-O-Ethyl-β-D-glucopyranoside (1) Preparation of Authentic Carbonyl Sugars and Their Analysis by Gas Chromatography and Mass Spectrometry

Methyl 4-O-ethyl-β-D-glucopyranoside (1) was prepared as a model compound for cellulose to investigate the reactions of ozone with polysaccharides during ozone bleaching of kraft pulp. The model compound was converted into authentic carbonyl sugars, methyl 3,6-di-O-acetyl-4-O-ethyl-β-D-arabino-hexopyranosidulose (2), methyl 2,6-di-O-acetyl-4-O-ethyl-β-D-ribo-hexopyranoside-3-ulose (3), methyl 2,3-di-O-acetyl-4-O-ethyl-β-D-gluco-hexodialdo-1,5-pyranoside (4). These carbonyl sugars were converted into O-methyloximes and analyzed by gas chromatography and mass spectrometry.     

n-type conductivity of phosphorus-doped homoepitaxial single crystal diamond on (001) substrate

The macroscopic surface morphology and crystallinity of (001) n-type diamond films, which have been quite recently achieved by P-doping using plasma-enhanced chemical vapor deposition technique, were studied. The observation of diffraction spots, streaks, and Kikuchi patterns in reflection high energy electron diffraction analysis indicated that the surface smoothness and the crystallinity were fine. Regarding the electrical properties of (001) n-type diamond films, Hall-effect measurements over a wide temperature range from 260 to 1000 K were investigated. The conduction band transport without the effect of hopping transport was confirmed within this experimental temperature range.     

Quadrature operators with arbitrary phase and applications to phase-space distribution and quantum communication

Quadrature operators with arbitrary phase are studied from a point of view of the phase-space representation of quantum states, and the results are applied to simultaneous measurement and quantum communication. The Wigner function of arbitrary phase quadrature variables is introduced, which is a generalization of the usual Wigner function of position and momentum. The Kirkwood distribution is also extended for arbitrary phase quadrature variables. The simultaneous measurement of two quadrature operators is investigated using a beam splitter model and a generalized version of the Arthurs-Kelley model. The quantum teleportation of continuous variables is considered in terms of arbitrary phase quadrature variables. A general formula is derived that provides the quantum teleportation channel. The fidelity of the quantum teleportation with an uncontrollable phase is calculated for a coherent state. Furthermore, the mutual information of the quantum dense coding of continuous variables is obtained when classical information is encoded on arbitrary phase quadrature variables. The result is compared with that of the communication system, where information is transmitted using coherent and squeezed states.     

Scattering of a light wave by a thin fiber on or near a prism: experiment and analytical theory

We have performed an experiment of the scattering of the near field on a prism created by a laser wave, evanescent wave (EW), or plane wave (PW) of an incident angle slightly larger than or smaller than the critical angle, by a thin fiber of subwavelength diameter set above the prism, and we made an analytical theory of an adapted model for the experiment. We have been able to analyze the experimental data exactly by the model theory better than any other theory we have ever known. The importance of the multiple interaction of the wave between the fiber and the surface and also the close similarity of the scattering characteristics between the EW and the PW mentioned above have been acknowledged by the analysis of the data obtained.     

Phonon scattering and thermal conduction mechanisms of sintered aluminium nitride ceramics

From thermal diffusivity measurements of sintered AIN at temperatures ranging from 100 to 1000 K, the phonon mean free path of AIN was calculated in order to investigate phonon scattering mechanisms. The calculated mean phonon scattering distance was increased with decreasing temperature. The mean phonon-defect scattering distances were respectively limited to about 50 nm at temperatures ranging from 100 to 270 K and about 30 nm at temperatures ranging from 100 to 700 K, for AIN specimens with a room-temperature thermal conductivity of 220 and 121 Wm^–1 K^–1 containing 0.1 and 1.4 wt % oxygen, respectively. These short phonon-defect scattering distances were considered to correspond to the separation of oxygen-related internal defects in AIN grains. Calculation of the mean phonon scattering frequencies indicated that the phonon scattering is dominated by phonon-defect scattering at temperatures below 270 K for an AIN specimen with an oxygen content of 0.1 wt %, and at temperatures below 350 K for an AIN specimen with an oxygen content of 1.4 wt %.     

Estimation of culm volume for bamboo, Phyllostachys bambusoides, by two-way volume equation

We determined a two-way volume equation for estimating the apparent culm volume for Phyllostachys bambusoides Sieb. et Zucc. The culm form analysis indicated that the normal form-factors at 0.6 and 0.9 in relative height were steady at 0.736 and 0.543, respectively. Substituting these normal form-factors and their relative heights into a generalized volume equation from the literature, the coefficients of the volume equation for P. bambusoides were determined. The applicability of the determined volume equation was evaluated using the test data collected from four different districts. The volume equation worked as a good model for estimating apparent culm volume for P. bambusoides, although it provided an underestimation of the culm volume when the site productivity was low. The result also demonstrated that there was a need for distinguishing the volume equation among bamboo species, because of the variability in the culm form. In conclusion, the volume equation presented here is one of the most effective models for evaluating the culm volume or stock for P. bambusoides.     

Formation of a heavily B doped diamond layer using an ion implantation technique

In this report, we present a study on lattice and electronic structures of B doped layers formed using B implantation into diamond. Boron layers were produced using the multiple-energy B ion implantation (total dose: 2.1 × 10¹⁵ to 1.7 × 10¹⁷ cm^− 2) into type IIa diamond at ~ 400 °C. Optical absorption and Hall effects were measured in the range of 80−1000 K for investigating the change of the lattice and electronic structures with the B concentration in diamond. The p-type carrier conduction was observed at 80−1000 K in all the samples. While a lightly B doped sample displays typical semiconductive, temperature-dependent valence-band conduction, heavily B doped samples have the very weak or almost zero temperature dependence of the carrier concentrations, resistivity and Hall mobility in this temperature region, suggesting characteristics of a p-type degenerate semiconductor. In such heavily doped samples, broad optical absorption bands, most likely corresponding to Drude absorption originating from free holes, were observed. The minimum resistivity and the sheet resistance at room temperature among the samples were 1.4 mΩcm and 56 Ω/□, respectively. These results indicate that very low-resistive p-type degenerate semiconducting layers were produced, preserving diamond lattice (preventing graphitization), despite high-dose ion irradiation.     

Fire-suppression characteristics of CF3H in a cup burner

A numerical investigation is performed to understand the inhibition characteristics of CF₃H in a periodically oscillating methane-air jet diffusion flame formed over a cup burner. A detailed chemical kinetic mechanism having 82 species and 1510 elementary-reaction steps is used. Calculations made without adding agent yielded an oscillating flame with a flicker frequency of 11 Hz, which compared well with that obtained in the experiment. The minimum concentration of agent required for extinguishing the cup-burner flame is determined by adding CF₃H to the air stream and by increasing its volume fraction gradually until the flame is completely extinguished. Addition of CF₃H at volume fractions up to 10.05% did not affect the cup-burner flame temperature significantly. Extinction of a cup-burner flame took place as the base of the flame became destabilized, and the unstable flame base moved downstream in search of a new stabilization location. The predicted minimum concentrations of CF₃H for extinguishing the flame obtained by (1) replacing the air with CF₃H and (2) replacing the N₂ in the air with CF₃H are 10.1 and 19.2%, respectively. These concentrations compare favorably with the corresponding measured values of 11.7 and 20.3%, respectively. For validation, calculations are also made for the steady counterflow diffusion flames with different concentrations of CF₃H in the air stream and the predicted volume fractions of agent at extinction are in good agreement with the experimental values published in the literature. Examination of the reaction rates for the cup-burner flames indicates that the reactions with fluorinated species reduce the concentration of chain-carrying radicals in the flame. The effect is stronger at the flame base than further up in the trailing part of the flame, leading to destabilization at the flame base prior to extinction in the trailing region, and yielding the observed blowoff-type extinction.     

Electrical properties of B-doped homoepitaxial diamond (001) film

Relationship between growth condition and quality of homoepitaxially grown B-doped diamond (001) film has been studied using physical measurements of defect density as a function of doping concentration. In particular, electrical properties of the homoepitaxial diamond film were characterized using measurements of conductivity, carrier concentration and mobility. The highest mobility is found to be about 1000 cm²V⁻¹s⁻¹ at 293 K, indicating that the quality of the CVD diamond film is further improved through optimizing the growth condition. The density of the compensation donor was determined from the temperature-dependent hole concentration. The lowest donor density is found to be 8.4 × 10¹⁵ cm⁻³ in the present work. This is an order of magnitude greater than the lowest value measured in natural IIb diamond. Furthermore, it is also found that the donor density increases with increasing doping concentration during the growth. On the other hand, the mobility decreases rapidly with increasing doping concentration. From these results, we speculate that the compensation donor is an origin of an additional scattering center in diamond, and excessive B-doping makes the quality of the CVD diamond worse.